December 2012Multimodal Magnetic Resonance Imaging Assessment of White Matter Aging Trajectories Over the Lifespan of Healthy Individuals.
Bartzokis G, Lu PH, Heydari P, Couvrette A, Lee GJ, Kalashyan G, Freeman F, Grinstead JW, Villablanca P, Finn JP, Mintz J, Alger JR, Altshuler LL.
BACKGROUND: Postmortem and volumetric imaging data suggest that brain myelination is a dynamic lifelong process that, in vulnerable late-myelinating regions, peaks in middle age. We examined whether known regional differences in axon size and age at myelination influence the timing and rates of development and degeneration/repair trajectories of white matter (WM) microstructure biomarkers. METHODS: Healthy subjects (n = 171) 14-93 years of age were examined with transverse relaxation rate (R(2)) and four diffusion tensor imaging measures (fractional anisotropy [FA] and radial, axial, and mean diffusivity [RD, AxD, MD, respectively]) of frontal lobe, genu, and splenium of the corpus callosum WM (FWM, GWM, and SWM, respectively).
December 2012Detection of 2-Hydroxyglutaric Acid in vivo by Proton Magnetic Resonance Spectroscopy in U87 Glioma Cells Overexpressing Isocitrate Dehydrogenase-1 Mutation.
Lazovic J, Soto H, Piccioni D, Lo Ru JR, Li S, Mirsadraei L, Yong W, Prins R, Liau LM, Ellingson BM, Cloughesy TF, Lai A, Pope WB.
The arginine 132 (R132) mutation of isocitrate dehydrogenase -1 (IDH1(R132)) results in production of 2-hydroxyglutarate (2-HG) and is associated with a better prognosis compared with wild-type (WT) in glioma patients. The majority of lower-grade gliomas express IDH1(R132), whereas this mutation is rare in grade IV gliomas. The aim of this study was to noninvasively investigate metabolic and physiologic changes associated with the IDH1 mutation in a mouse glioma model. Using a 7T magnet, we compared MRI and proton magnetic resonance spectroscopy (MRS) in U87 glioma cells overexpressing either the mutated IDH1(R132) or IDH1 wild-type (IDH1(WT)) gene in a mouse flank xenograft model. Flank tumors overexpressing IDH1(R132) showed a resonance at 2.25 ppm corresponding to the 2-HG peak described for human IDH1(R132) gliomas. WT tumors lacked this peak in all cases. IDH1 mutant tumors demonstrated significantly reduced glutamate by in vivo MRS. There were no significant differences in T(2), apparent diffusion coefficient (ADC), or perfusion values between the mutant and IDH1(WT) tumors. The IDH1(R132) mutation results in 2-HG resonance at 2.25 ppm and a reduction of glutamate levels as determined by MRS. Our results establish a model system where 2-HG can be monitored noninvasively, which should be helpful in validating 2-HG levels as a prognostic and/or predictive biomarker in glioma.
December 2012Patients' Willingness to Participate in a Breast Cancer Biobank at Screening Mammogram.
Lee CI, Bassett LW, Leng M, Maliski SL, Pezeshki BB, Wells CJ, Mangione CM, Naeim A.
To characterize patients' willingness to donate a biospecimen for future research as part of a breast cancer-related biobank involving a general screening population. We performed a prospective cross-sectional study of 4,217 women aged 21-89 years presenting to our facilities for screening mammogram between December 2010 and October 2011. This HIPAA-compliant study was approved by our institutional review board. We collected data on patients' interest in and actual donation of a biospecimen, motivators and barriers to donating, demographic information, and personal breast cancer risk factors. A multivariate logistic regression analysis was performed to identify patient-level characteristics associated with an increased likelihood to donate. Mean patient age was 57.8 years (SD 11.1 years). While 66.0% (2,785/4,217) of patients were willing to donate blood or saliva during their visit, only 56.4% (2,378/4,217) actually donated. Women with a college education (OR = 1.27, p = 0.003), older age (OR = 1.02, p < 0.001), previous breast biopsy (OR = 1.23, p = 0.012), family history of breast cancer (OR = 1.23, p = 0.004), or a comorbidity (OR = 1.22, p = 0.014) were more likely to donate. Asian-American women were significantly less likely to donate (OR = 0.74, p = 0.005). The major reason for donating was to help all future patients (42.3%) and the major reason for declining donation was privacy concerns (22.3%). A large proportion of women participating in a breast cancer screening registry are willing to donate blood or saliva to a biobank. Among minority participants, Asian-American women are less likely to donate and further qualitative research is required to identify novel active recruitment strategies to insure their involvement.
December 2012Neuropsychological Function and Cerebral Metabolites in HIV-infected Youth.
Nagarajan R, Sarma MK, Thomas MA, Chang L, Natha U, Wright M, Hayes J, Nielsen-Saines K, Michalik DE, Deville J, Church JA, Mason K, Critton-Mastandrea T, Nazarian S, Jing J, Keller MA.
The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV- youths (13-25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV- controls, HIV+ subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p = 0.016) and higher Scy/total choline (tCho) (+31%, p = 0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p = 0.022) and higher Glu/tCho (+15%, p = 0.048) than controls. HIV+ subjects demonstrated poorer attention/processing speed (p = 0.011, d = 1.03) but similar psychomotor and executive function compared to HIV- controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r = -0.75, p = 0.0019) in the HIV- controls, but not in the HIV+ subjects (Fisher's r-z transformation, p < 0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.
December 20122D MR Spectroscopy Combined with Prior-Knowledge Fitting Is Sensitive to HCV-Associated Cerebral Metabolic Abnormalities.
Nagarajan R, Sarma MK, Thames AD, Castellon SA, Hinkin CH, Thomas MA.
There is an evidence of neurocognitive dysfunction even in the absence of advanced liver disease in chronic hepatitis C virus (HCV) infection. Brain metabolism has been investigated non-invasively using one-dimensional (1D) in vivo Magnetic Resonance Spectroscopy (MRS) over three decades. Even though highly concentrated cerebral metabolites (N-acetylaspartate, creatine, choline, glutamate/glutamine, myo-inositol) have been detected using MRS, other metabolites at low concentrations (~1-3mM or less) including glutathione, aspartate and GABA are quite difficult to observe using 1D MRS. In order to resolve overlapping resonances from a number of metabolites, a remedy is to add a second spectral dimension to the existing 1D MRS. Localized two-dimensional correlated spectroscopy (L-COSY) has been developed over the last decade to enhance the spectral dispersion by using the second spectral dimension. We have evaluated this L-COSY technique in the frontal white/gray matter regions of 14 HCV+ (mean age of 56.2 years) and 14 HCV- (mean age of 46.6 years) subjects. Our preliminary results showed significantly increased myo-inositol and glutathione in the HCV+ compared to the HCV- subjects. Hence, glutathione and myo-inositol should be considered along with other metabolites as important markers of inflammation.
December 2012Pulmonary 64-MDCT Angiography With 30 mL of IV Contrast Material: Vascular Enhancement and Image Quality.
Wu CC, Lee EW, Suh RD, Levine BS, Barack BM.
OBJECTIVE: The objective of our study was to determine whether vascular enhancement and image quality can be preserved in pulmonary CT angiography (CTA) performed on a 64-MDCT scanner with 30 mL of IV contrast material. MATERIALS AND METHODS: This retrospective matched-cohort study compared image quality of pulmonary CTA performed using 30 mL of IV contrast material versus 100 mL of IV contrast material. CT images of 50 patients (46 men, four women; mean age, 66 years) who underwent pulmonary CTA on a 64-MDCT scanner using a low dose (30 mL) of iodixanol 320 and another 50 patients (49 men, one woman; mean age, 65 years) who underwent pulmonary CTA using a regular dose (100 mL) of contrast material during the same time period were selected for review. The 30- and 100-mL pulmonary CTA studies were retrospectively evaluated by two thoracic radiologists in random order. Attenuation values were recorded over the main, right main, selected lobar, segmental, and subsegmental pulmonary arteries. Image quality was also subjectively assessed using visual scores on a scale from 1 (nondiagnostic) to 5 (excellent).
November 2012Direct Thrombus Aspiration Using the Penumbra System for the Treatment of Pediatric Intracranial Dissection.
Fujimoto M, Tateshima S, Ali L, Raychev R, Viñuela F.
We describe a case of a 15-year-old girl who developed a spontaneous intracranial arterial dissection with distal middle cerebral artery (MCA) occlusions. From the digital subtraction angiography provided, the dissection flap appeared to originate at the internal carotid artery terminus with extension into the right M1 segment and occluding the right anterior cerebral artery, A1 segment. CT perfusion study showed salvageable tissue in the posterior MCA territory, including the motor cortex. In order to avoid further injury to the dissection, clot retrieval systems were not a treatment option. We therefore performed selective thrombus aspiration with the Penumbra system for the occluded central and precentral arteries distal to the non-occlusive dissecting lesion. Sufficient recanalization was achieved and the patient made a marked recovery. Although mechanical thrombectomy with the use of retrieval intracranial stent systems has demonstrated satisfactory recanalization rates, the aspiration methodology remains useful for patients with an accompanying proximal vascular lesion.
November 2012Pediatric Epilepsy Surgery: Long-term 5-Year Seizure Remission and Medication Use.
Hauptman JS, Pedram K, Sison CA, Sankar R, Salamon N, Vinters HV, Mathern GW.
BACKGROUND: It is unclear whether long-term seizure outcomes in children are similar to those in adult epilepsy surgery patients. OBJECTIVE: To determine 5-year outcomes and antiepilepsy drug (AED) use in pediatric epilepsy surgery patients from a single institution. METHODS: The cohort consisted of children younger than 18 years of age whose 5-year outcome data would have been available by 2010. Comparisons were made between patients with and without 5-year data (n = 338), patients with 5-year data for seizure outcome (n = 257), and seizure-free patients on and off AEDs (n = 137).
November 2012Primary Carcinoid Tumor of Urinary Bladder Discovered on Pelvic Magnetic Resonance Imaging.
Kaplan AL, Margolis DJ, Said J, Chin AI.
Pure primary carcinoid tumor of the urinary bladder is an exceedingly rare lesion with less than twenty cases reported in the English language literature. These tumors are typically small and rarely invade past the lamina propria. Amenable to transurethral resection alone, they are associated with a favorable prognosis. We present a case of pure primary carcinoid tumor of the bladder discovered on T2-weighted pelvic magnetic resonance imaging.
November 2012Ordering of CT by Emergency Department Provider Type: Analysis of a Nationally Representative Sample.
Lee CI, Ponce NA, Ettner SL, Kahn KL, Bassett LW, Forman HP.
OBJECTIVE: Given the growing concern about CT overutilization, we provide a descriptive trend analysis of CT studies ordered in U.S. emergency departments by nonphysician health care providers and examine whether there is a significant difference in ordering patterns between nonphysicians and physicians. MATERIALS AND METHODS: We used a nationally representative data sample for 2001-2008 to describe trends in CT studies ordered in U.S. emergency departments by nonphysician health care providers. We performed a multivariate logistic regression with hospital fixed effects on the most recently available data to determine whether there is a difference in ordering patterns between the two provider groups.
November 2012Irreversible Electroporation in Porcine Liver: Short- and Long-Term Effect on the Hepatic Veins and Adjacent Tissue by CT With Pathological Correlation.
Lee YJ, Lu DS, Osuagwu F, Lassman C.
OBJECTIVE: The objective of the study was to determine the short- and long-term effects of irreversible electroporation (IRE) on the hepatic veins and the perivascular tissue through serial computed tomography (CT) with pathological correlation. MATERIALS AND METHODS: Multiple IRE lesions were created percutaneously by ultrasound guidance in livers of 11 Yorkshire pigs using a prototype IRE generator. Paired electrodes were used. Three pigs were killed at the same day; 2 pigs, at 2 days; 2 pigs, at 2 weeks; 2 pigs, at 4 weeks; and 2 pigs, at 8 weeks. Contrast-enhanced CT was performed in all pigs initially and thereafter at selected intervals. Pathological sections were performed for correlation. Initial CT scans were analyzed for lesions for degree of circumferential contact (<25%, 26%-50%, 51%-75%, and 76%-100%) to the hepatic veins for analysis of any contour deformity. The hepatic veins were also analyzed for any thrombus and for any narrowing. Those lesions with follow-up scans were also analyzed for changes over time.
November 2012MRI Detection of Intratumoral Fat in Hepatocellular Carcinoma: Potential Biomarker for a More Favorable Prognosis.
Siripongsakun S, Lee JK, Raman SS, Tong MJ, Sayre J, Lu DS.
OBJECTIVE: The purpose of this study was to determine whether the presence of intratumoral fat in hepatocellular carcinoma (HCC) could serve as an imaging biomarker to predict a favorable prognosis. MATERIALS AND METHODS: After a search of the radiology and pathology databases from January 2002 to December 2010, a cohort of patients with fat-containing HCC imaged by chemical-shift MRI techniques was matched with a cohort of patients with nonfat-containing HCC for TNM stage and type of subsequent treatment. The number and type of tumor progression, time to tumor progression (TTP), and overall survival (OS) were determined for each cohort.
November 2012Contrast-Enhanced MR Angiography of Cavopulmonary Connections in Adult Patients With Congenital Heart Disease.
Wagner M, Nguyen KL, Khan S, Mirsadraee S, Satou GM, Aboulhosn J, Finn JP.
OBJECTIVE: The purpose of this study is to evaluate combined time-resolved and high-spatial resolution contrast-enhanced MR angiography (MRA) for assessment of cavopulmonary connections in adult patients with congenital heart disease. MATERIALS AND METHODS: Twenty-eight adults with various surgical cavopulmonary connections (Glenn shunt and Fontan connection) underwent high-spatial-resolution contrast-enhanced MRA (voxel size, 1.95 mm(3); temporal resolution, 22 seconds) and time-resolved contrast-enhanced MRA (voxel size, 6.5-9.3 mm(3); temporal resolution, < 1.2 seconds). Ten patients had 2D phase contrast flow quantification measurements performed at the same setting. Two readers independently assessed anatomic dimensions of cavopulmonary connections (using high-spatial-resolution contrast-enhanced MRA) and pulmonary artery (PA) perfusion patterns (using time-resolved contrast-enhanced MRA).
November 2012Age, Sex, and Hypertension-Related Remodeling Influences Left Ventricular Torsion Assessed by Tagged Cardiac Magnetic Resonance in Asymptomatic Individuals: the Multi-Ethnic Study of Atherosclerosis.
Yoneyama K, Gjesdal O, Choi EY, Wu CO, Hundley WG, Gomes AS, Liu CY, McClelland RL, Bluemke DA, Lima JA.
BACKGROUND: The aim of the present study was to evaluate how torsion is influenced by left ventricular (LV) remodeling associated with age, sex, and hypertension in a large community-based population. METHODS AND RESULTS: Myocardial shortening and torsion were assessed by tagged cardiac magnetic resonance in 1478 participants without clinically apparent cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis (MESA). Torsion was defined as the difference between apical and basal rotation divided by slice distance. In multivariable linear regression models, older age was associated with lower stroke volume (-3.6 mL per decade; P<0.001) and higher LV mass-to-volume ratio (0.03 g/mL per decade; P<0.001), along with lower circumferential shortening (-0.17% per decade; P<0.05). Torsion, however, was greater at older ages (0.14° per decade; P<0.001) and in women (0.37°/cm versus men; P<0.001). Hypertensive participants had higher LV mass and LV mass-to-volume ratio (15.5 g and 0.07 g/mL, respectively; P<0.001 for both). Circumferential shortening was lower in hypertensive (-0.42%; P<0.01), whereas torsion was higher after adjustment for age and sex (0.17°/cm; P<0.05).
October 2012Measuring Radiology's Value in Time Saved.
Lee CI, Enzmann DR.
Because radiology has historically not measured its added value to patient care and thus not communicated it in easily understood terms to all stakeholders, the specialty must correct this to prepare for the eventual transition from the current fee-for-service payment schedule to new value-based reimbursement systems. Given the increasing risk for marginalization, radiologists need to engage clinicians and managers to map the processes and associated costs of episodes of patient care to identify areas for providing and improving integrated diagnostic information and to measure the value thereof. In such time-driven, activity-based costing practices, radiologists should highlight how proper investments in the information generated by imaging and how radiologists' associated consultative and coordination of services can save greater resources downstream, especially in the nonrenewable resource of physician time, an increasingly scarce health care resource. Using physician time in the most efficient way will be a key element for decreasing health care costs at the aggregate level. Therefore, expressing radiology's contribution in terms of downstream physician time saved is a metric that can be easily understood by all stakeholders. In a conceptual framework centered on value, the specialty of radiology must focus more on its most important product, actionable information, rather than on imaging technologies themselves. Information, unlike imaging technologies, does not depreciate with time but rather increases in value the more it is used.
October 2012Obliterative (Constrictive) Bronchiolitis.
Lynch JP 3rd, Weigt SS, Derhovanessian A, Fishbein MC, Gutierrez A, Belperio JA.
Obliterative bronchiolitis (OB) (formerly termed bronchiolitis obliterans), is a rare fibrotic disorder involving terminal and respiratory bronchioles. The term constrictive bronchiolitis is synonymous with OB. Clinically, OB is characterized by progressive (often fatal) airflow obstruction, the absence of parenchymal infiltrates on chest radiographs, a mosaic pattern of perfusion on high-resolution computed tomographic scan, poor responsiveness to therapy, and high mortality rates. Most cases of OB occur in the context of a specific risk factor. Currently, most cases of OB occur in lung transplant recipients with chronic allograft rejection or hematopoietic stem cell transplant (HSCT) recipients with graft versus host disease (GVHD). Other causes of OB include connective tissue disease (CTD) (particularly rheumatoid arthritis); lower respiratory tract infections; inhalation injury; exposure or inhalation of toxic fumes, metals, dusts, particulate matter, or pollutants; occupational exposures; drug reactions; consumption of uncooked leaves of Sauropus androgynus; chronic hypersensitivity pneumonia; diffuse neuroendocrine cell hyperplasia; miscellaneous. When no cause is identified, the term cryptogenic obliterative bronchiolitis is used. This review discusses the salient clinical, radiographic, and histological features of OB and presents a management approach.
October 2012Solitaire Flow Restoration Device Versus the Merci Retriever in Patients with Acute Ischaemic Stroke (SWIFT): a Randomized, Parallel-Group, Non-Inferiority Trial.
Saver JL, Jahan R, Levy EI, Jovin TG, Baxter B, Nogueira RG, Clark W, Budzik R, Zaidat OO; SWIFT Trialists.
BACKGROUND: The Solitaire Flow Restoration Device is a novel, self-expanding stent retriever designed to yield rapid flow restoration in acute cerebral ischaemia. We compared the efficacy and safety of Solitaire with the standard, predicate mechanical thrombectomy device, the Merci Retrieval System. METHODS: In this randomized, parallel-group, non-inferiority trial, we enrolled patients from 18 sites (17 in the USA and one in France). Patients were eligible for inclusion if they had acute ischaemic stroke with moderate to severe neurological deficits and were treatable by thrombectomy within 8 h of stroke symptom onset. We used a computer-generated randomisation sequence to randomly allocate patients to receive thrombectomy treatment with either Solitaire or Merci (1:1; block sizes of four and stratified by centre and stroke severity). The primary endpoint was Thrombolysis In Myocardial Ischemia (TIMI) scale 2 or 3 flow in all treatable vessels without symptomatic intracranial haemorrhage, after up to three passes of the assigned device, as assessed by an independent core laboratory, which was masked to study assignment. Primary analysis was done by intention to treat. A prespecified efficacy stopping rule triggered an early halt to the trial. The study is registered with ClinicalTrials.gov, number NCT 01054560.
October 2012Impact of Merci Device Fracture on Clinical Outcome of Acute Ischemic Stroke after Mechanical Thrombectomy.
Shi ZS, Duckwiler GR, Loh Y, Liebeskind DS, Gonzalez NR, Tateshima S, Jahan R, Saver JL, Viñuela F.
AIMS: To investigate the frequency and predictors of Merci device fracture in patients with acute ischemic stroke treated with mechanical thrombectomy and its impact on clinical outcome. METHODS: We retrospectively analyzed patients with acute ischemic stroke treated by thrombectomy with the Merci Retriever and identified the presence of device fracture. The predictors of device fracture were assessed. We evaluated the impact of device fracture on hemorrhage and clinical outcome.
September 2012Breast Density Legislation and Opportunities for Patient-Centered Outcomes Research.
Lee CI, Bassett LW, Lehman CD.
One important strategy for reducing breast cancer mortality is early detection through screening (1). Despite a reported decline in mortality rates because of mammography, its effectiveness remains heavily debated. Exemplified by the breast imaging community's backlash against the U.S. Preventive Services Task Force (USPSTF) for its recommendation not to routinely screen women aged 40-49 years, the interpretation of available evidence remains a highly charged and emotional issue for many stakeholders (2)...
September 2012Imaging of the Shoulder: a Comparison of MRI and Ultrasound.
Levine BD, Motamedi K, Seeger LL.
Magnetic resonance imaging (MRI) is well established as a powerful imaging modality for the shoulder. In the last decade, ultrasound has emerged as an effective imaging option, alongside MRI, for evaluation of the shoulder. With MRI and ultrasound, clinicians now have two viable advanced imaging options for the diagnostic evaluation of shoulder pain. This article discusses the advantages and disadvantages of ultrasound and MRI for the shoulder. Applications where ultrasound is considered the imaging test of choice, those where MRI is more advantageous, and those where both ultrasound and MRI are viable alternatives for shoulder imaging are discussed.
September 2012Injection of Gadolinium Contrast Through Pediatric Central Venous Catheters: A Safety Study.
Moriarty JM, Kung GL, Ramos Y, Moghaddam AN, Ennis DB, Finn JP.
BACKGROUND: Catheter rupture during CT angiography has prompted policies prohibiting the use of electronic injectors with peripherally inserted central venous catheters (PICCs) not only for CT but also for MRI. Consequently, many institutions mandate hand injection for MR angiography, limiting precision of infusion rates and durations of delivery. OBJECTIVE: To determine whether electronic injection of gadolinium-based contrast media through a range of small-caliber, single-lumen PICCs would be safe without risk of catheter rupture over the range of clinical protocols and determine whether programmed flow rates and volumes were realized when using PICCs for contrast delivery. MATERIALS AND METHODS: Experiments were performed and recorded using the Medrad Spectris Solaris EP MR Injection System. PICC sizes, contrast media and flow rates were based on common institutional protocols.
September 2012Non-Super-Selective Venous Sampling for Persistent Hyperparathyroidism Using a Systemic Hypocalcemic Challenge.
Morris LF, Loh C, Ro K, Wiseman JE, Gomes AS, Asandra A, Wariri S, Yeh MW.
PURPOSE: To describe a new protocol employing an acute systemic hypocalcemic challenge (SHC) aimed at augmenting the parathyroid hormone (PTH) gradient to enable non-super-selective venous sampling (VS) in patients with persistent primary hyperparathyroidism (PHPT). MATERIALS AND METHODS: In a retrospective study, 37 patients (39 studies-20 SHC, 19 super-selective VS) who underwent VS for persistent or recurrent PHPT were examined. Study patients were pretreated with intravenous hydration, diuretics, and bicarbonate to induce temporary relative hypocalcemia and then underwent non-super-selective VS targeted at large vessels within the neck and chest with rapid PTH testing. The traditional VS protocol involved super-selective VS with arteriography.
September 201249-Year-Old Transplant Recipient with Fever and Altered Mental Status.
Mukherjee AK, Solis OE, Salamon N, Mehta RI.
A 49-year-old man presented with fever and altered mental status. He had a complex prior medical history notable for type I diabetes mellitus with end-stage renal disease and peripheral vascular disease. Eight years prior to admission he underwent pancreatic and renal transplantation secondary to diabetes. The renal transplantation procedure was initially complicated by intra-operative myocardial infarction, and subsequently by acute and chronic allograft rejection. Consequently, the patient had been on long-term immunosuppressive therapy. He also suffered from chronic atrial fibrillation requiring warfarin and had undergone cardiac valve replacement one year earlier.
September 2012MR Spectroscopic Imaging and Diffusion-Weighted Imaging of Prostate Cancer with Gleason Acores.
Nagarajan R, Margolis D, Raman S, Sarma MK, Sheng K, King CR, Verma G, Sayre J, Reiter RE, Thomas MA.
PURPOSE: To investigate functional changes in prostate cancer patients with three pathologically proven different Gleason scores (GS) (3+3, 3+4, and 4+3) using magnetic resonance spectroscopic imaging (MRSI) and diffusion-weighted imaging (DWI). MATERIALS AND METHODS: In this study MRSI and DWI data were acquired in 41 prostate cancer patients using a 1.5T MRI scanner with a body matrix combined with an endorectal coil. The metabolite ratios of (Cho+Cr)/Cit were calculated from the peak integrals of total choline (Cho), creatine (Cr), and citrate (Cit) in MRSI. Apparent diffusion coefficient (ADC) values were derived from DWI for three groups of Gleason scores. The sensitivity and specificity of MRSI and DWI in patients were calculated using receiver operating characteristic curve (ROC) analysis.
September 2012Image-Guided Ablative Therapies for Lung Cancer.
Sharma A, Abtin F, Shepard JA.
Lung cancer is the commonest cause of death in adults. Although the treatment of choice is surgical resection with lobectomy, many patients are nonsurgical candidates because of medical comorbidities. Patients may also have recurrent disease after resection or radiotherapy and some patients refuse surgical options. Image-guided ablation has been recently introduced as a safe, alternative treatment of localized disease in carefully selected patients. This article discusses the principles, technique, and follow-up of the 3 main ablative therapies currently used in the lung, radiofrequency ablation, microwave ablation, and percutaneous cryotherapy.
September 2012Stenting in Acute Stroke: Counterpoint.
The act of intracranial stent placement in acute stroke patients with thromboembolic occlusions was justified based on the premise that the FDA-approved devices did not provide an adequately high recanalization rate and/or a good clinical outcome. The patients were put on a dual antiplatelet regime after stent placement despite the potential risk of worsening in the intracranial hemorrhage. Past retrospective clinical series on intracranial stent placement in patients with acute stroke demonstrated higher recanalization rates than the Merci (Stryker / Concentric Medical, Mountain View, CA, USA) and Multi-Merci trials with the use of older generation Merci retrievers, hence the benefits might outweigh the potential risk of hemorrhage for a certain subpopulation of acute stroke patients. The reported recanalization rates and clinical outcomes from medical centers in the USA have not been substantially different among the FDA-approved mechanical thrombectomy or aspiration devices until recently.
September 2012Radiogenomic Analysis of Breast Cancer Using MRI: A Preliminary Study to Define the Landscape.
Yamamoto S, Maki DD, Korn RL, Kuo MD.
OBJECTIVE: Molecular profiling studies have defined the increasing importance of gene expression phenotyping in breast cancer. However, the relationship between global transcriptomic profiles and the information provided by breast MRI remains to be examined. In this pilot study, our aim was to provide a preliminary radiogenomic association map linking MR image phenotypes to underlying global gene expression patterns in breast cancer. MATERIALS AND METHODS: From a multiinstitutional study, a total of 353 patients with a diagnosis of breast cancer were examined for gene expression analysis. Radiogenomic analysis was then performed on a subset of these patients (n = 10) who also underwent breast MRI. Two radiologists evaluated each MRI study across 26 predefined imaging phenotypes. Analyses were performed to correlate the expression and imaging data and to define associations between specific MR image phenotypes and gene sets of interest.
August 2012High-Sensitivity C-Reactive Protein as an Independent Predictor of Progressive Myocardial Functional Deterioration: The Multiethnic Study of Atherosclerosis.
Choi EY, Yan RT, Fernandes VR, Opdahl A, Gomes AS, Almeida AL, Wu CO, Liu K, Carr JJ, McClelland RL, Bluemke DA, Lima JA.
BACKGROUND: Systemic inflammation has been linked to the development of heart failure in population studies including Multi-Ethnic Study of Atherosclerosis (MESA), but little evidence exists regarding potential mechanism of this relationship. In this study, we used longitudinal magnetic resonance imaging follow-up analysis to examine whether C-reactive protein (CRP) levels relate to progressive myocardial functional deterioration as a potential mechanism of incident heart failure. METHODS: Regional myocardial functional data from MESA participants who had baseline CRP measurement and also underwent tagged cardiac magnetic resonance imaging both at baseline and at 5-year follow-up were analyzed. Left ventricular midwall and midslice peak circumferential strain (Ecc), of which a more negative value denotes stronger regional myocardial function, was measured. Circumferential strain change was calculated as the difference between baseline and follow-up Ecc.
August 201218F-FDOPA and 18F-FLT Positron Emission Tomography Parametric Response Maps Predict Response in Recurrent Malignant Gliomas Treated with Bevacizumab.
Harris RJ, Cloughesy TF, Pope WB, Nghiemphu PL, Lai A, Zaw T, Czernin J, Phelps ME, Chen W, Ellingson BM.
The current study examined the use of voxel-wise changes in 18F-FDOPA and 18F-FLT PET uptake, referred to as parametric response maps (PRMs), to determine whether they were predictive of response to bevacizumab in patients with recurrent malignant gliomas. Twenty-four patients with recurrent malignant gliomas who underwent bevacizumab treatment were analyzed. Patients had MR and PET images acquired before and at 2 time points after bevacizumab treatment. PRMs were created by examining the percentage change in tracer uptake between time points in each image voxel. Voxel-wise increase in PET uptake in areas of pretreatment contrast enhancement defined by MRI stratified 3-month progression-free survival (PFS) and 6-month overall survival (OS) according to receiver-operating characteristic curve analysis. A decrease in PET tracer uptake was associated with longer PFS and OS, whereas an increase in PET uptake was associated with short PFS and OS. The volume fraction of increased 18F-FDOPA PET uptake between the 2 posttreatment time points also stratified long- and short-term PFS and OS (log-rank, P < .05); however, 18F-FLT uptake did not stratify OS. This study suggests that an increase in FDOPA or FLT PET uptake on PRMs after bevacizumab treatment may be a useful biomarker for predicting PFS and that FDOPA PET PRMs are also predictive of OS in recurrent gliomas treated with bevacizumab.
August 2012The Dependence of Radiofrequency Induced Pacemaker Lead Tip Heating on the Electrical Conductivity of the Medium at the Lead Tip.
Langman DA, Goldberg IB, Judy J, Paul Finn J, Ennis DB.
Radiofrequency induced pacemaker lead tip heating is one of the main reasons magnetic resonance imaging (MRI) is contraindicated for patients with pacemakers. The objective of this work was to evaluate the dependence of pacemaker lead tip heating during MRI scanning on the electrical conductivity of the medium surrounding the pacemaker lead tip. The effect of conductivity was measured using hydroxyethyl cellulose, polyacrylic acid, and saline with conductivities ranging from 0 to 3 S/m which spans the range of human tissue conductivity. The maximum lead tip heating observed in polyacrylic acid was 50.4°C at 0.28 S/m, in hydroxyethyl cellulose the maximum was 36.8°C at 0.52 S/m, and in saline the maximum was 12.5°C at 0.51 S/m. The maximum power transfer theorem was used to calculate the relative power deposited in the solution based on the characteristic impedance of the pacemaker lead and test solution impedance. The results demonstrate a strong correlation between the relative power deposited and pacemaker lead tip heating for hydroxyethyl cellulose and saline solutions. Maximum power deposition occurred when the impedance of the solution matched the pacemaker lead impedance. Pacemaker lead tip heating is dependent upon the electrical conductivity of the solution at the lead tip and should be considered when planning in vitro gel or saline experiments.
August 2012Endoscopic Removal of Migrated Vascular Embolic Material from the Duodenum with Endovascular Control.
Moriarty JM, Shaw G, Xing M, Kee ST, Farrell JJ.
We describe a case of vascular embolic material erosion through the wall of a hepatic artery aneurysm (HAA) into the lumen of the duodenum, requiring endoscopic retrieval.
August 2012Radical Prostatectomy: Value of Prostate MRI in Surgical Planning
Tan N, Margolis DJ, McClure TD, Thomas A, Finley DS, Reiter RE, Huang J, Raman SS.
The introduction of serum prostate-specific antigen to the prostate cancer screening algorithm has led to an increase in prostate cancer diagnosis as well as a migration toward lower-stage cancer at the time of diagnosis. This stage migration has coincided with changes in treatment options; these include active surveillance, new therapies, and advances in surgical techniques. Use of robot-assisted radical prostatectomy (RARP) as a surgical technique has seen a significant increase over the past several years: the number of patients undergoing RARP has risen from 1% to 40% of all prostatectomies from 2001-2006 to as many as 80% in 2010. The robotic interface provides a 3D magnified view of the surgical field, intuitive instrument manipulation, motion scaling, tremor filtration, and excellent dexterity and range of motion. However, in some cases, the lack of tactile (haptic) feedback may limit the surgeon's decision making ability in assessing malignant involvement of the neurovascular bundles. Pre-operative planning relies on nomograms based on limited clinical and prostate biopsy information. The surgical decision to spare or resect the neurovascular bundles is based on clinical information which is not spatially or anatomically based. Advances in magnetic resonance imaging (MRI) may provide spatially localized information to fill this void and aid surgical planning, particularly for robotic surgeons. In this review, we discuss the potential role of pre-operative MRI in surgical planning for radical prostatectomy.
July 2012Radiofrequency Ablation of Lung Tumors: Imaging Features of the Postablation Zone.
Abtin FG, Eradat J, Gutierrez AJ, Lee C, Fishbein MC, Suh RD.
Radiofrequency ablation (RFA) is used to treat pulmonary malignancies. Although preliminary results are suggestive of a survival benefit, local progression rates are appreciable. Because a patient can undergo repeat treatment if recurrence is detected early, reliable post-RFA imaging follow-up is critical. The purpose of this article is to describe (a) an algorithm for post-RFA imaging surveillance; (b) the computed tomographic (CT) appearance, size, enhancement, and positron emission tomographic (PET) metabolic activity of the ablation zone; and (c) CT, PET, and dual-modality imaging with PET and CT (PET/CT) features suggestive of partial ablation or tumor recurrence and progression. CT is routinely used for post-RFA follow-up. PET and PET/CT have emerged as auxiliary follow-up techniques. CT with nodule densitometry may be used to supplement standard CT. Post-RFA follow-up was divided into three phases: early (immediately after to 1 week after RFA), intermediate (>1 week to 2 months), and late (>2 months). CT and PET imaging features suggestive of residual or recurrent disease include (a) increasing contrast material uptake in the ablation zone (>180 seconds on dynamic images), nodular enhancement measuring more than 10 mm, any central enhancement greater than 15 HU, and enhancement greater than baseline anytime after ablation; (b) growth of the RFA zone after 3 months (compared with baseline) and definitely after 6 months, peripheral nodular growth and change from ground-glass opacity to solid opacity, regional or distant lymph node enlargement, and new intrathoracic or extrathoracic disease; and (c) increased metabolic activity beyond 2 months, residual activity centrally or at the ablated tumor, and development of nodular activity.
July 2012Emphysema Lung Lobe Volume Reduction: Effects on the Ipsilateral and Contralateral Lobes.
Brown MS, Kim HJ, Abtin FG, Strange C, Galperin-Aizenberg M, Pais R, Da Costa IG, Ordookhani A, Chong D, Ni C, McNitt-Gray MF, Tashkin DP, Goldin JG.
OBJECTIVES: To investigate volumetric and density changes in the ipsilateral and contralateral lobes following volume reduction of an emphysematous target lobe. METHODS: The study included 289 subjects with heterogeneous emphysema, who underwent bronchoscopic volume reduction of the most diseased lobe with endobronchial valves and 132 untreated controls. Lobar volume and low-attenuation relative area (RA) changes post-procedure were measured from computed tomography images. Regression analysis (Spearman's rho) was performed to test the association between change in the target lobe volume and changes in volume and density variables in the other lobes.
July 2012Diffusion Tensor Magnetic Resonance Tractography of the Prostate: Feasibility for Mapping Periprostatic Fibers.
Finley DS, Ellingson BM, Natarajan S, Zaw TM, Raman SS, Schulam P, Reiter RE, Margolis D.
OBJECTIVE: To evaluate the feasibility of diffusion tensor imaging (DTI) tractography of the prostate for mapping of periprostatic neurovascular anatomy. METHODS: Eight men with prostate cancer scheduled to undergo nerve-sparing robot-assisted radical prostatectomy (RARP) underwent endorectal multiparametric magnetic resonance imaging (MRI) of the prostate with DTI. Tract mapping was accomplished by positioning spherical regions of interest contiguously along the prostatic capsule at the prostatic apex, midgland, and base.
July 2012Encouraging Women of Color to Enter Academic Medicine.
Guerrero L, Boechat MI.
July 2012Neuroimaging in the Definition and Organization of the Epilepsies: We're Not There Yet.
Hauptman JS, Salamon N, Mathern GW.
Neuroimaging significantly affects the diagnosis and treatment of patients with patients. Despite its importance, magnetic resonance imaging (MRI) has been marginally incorporated into concepts used to define epilepsy etiologies by the International League Against Epilepsy (ILAE) Classification Commission. We propose that Structural etiology be defined as positive neuroimaging abnormalities likely causing the seizures. This would contrast with Genetic and Unknown etiologies, where imaging shows no overt structural abnormality that explains the seizures. It is further recommended that Structural and Metabolic be separated into individual categories, as the outcomes and therapies are different. It is advocated that Structural etiology be subdivided into subgroups based on MRI and surgical syndromes. With this approach, the ILAE should acknowledge that both MRI and electroencephalography (EEG) are necessary diagnostic tools in the classification of epilepsy syndromes and etiologies in the modern era. Promoting the use of neuroimaging into concepts that determine terminology will promote the notion that epilepsy classification should consider structural etiology of the seizures, along with the frequency of the most common epilepsy syndromes, and prognosis for spontaneous and treated remission and cure.
July 2012Normal Left Ventricular Myocardial Thickness for Middle-Aged and Older Subjects with Steady-State Free Precession Cardiac Magnetic Resonance: the Multi-Ethnic Study of Atherosclerosis.
Kawel N, Turkbey EB, Carr JJ, Eng J, Gomes AS, Hundley WG, Johnson C, Masri SC, Prince MR, van der Geest RJ, Lima JA, Bluemke DA.
BACKGROUND: Increased left ventricular myocardial thickness (LVMT) is a feature of several cardiac diseases. The purpose of this study was to establish standard reference values of normal LVMT with cardiac magnetic resonance and to assess variation with image acquisition plane, demographics, and left ventricular function. METHODS & RESULTS: End-diastolic LVMT was measured on cardiac magnetic resonance steady-state free precession cine long and short axis images in 300 consecutive participants free of cardiac disease (169 women; 65.6±8.5 years) of the Multi-Ethnic Study of Atherosclerosis cohort. Mean LVMT on short axis images at the mid-cavity level was 5.3±0.9 mm and 6.3±1.1 mm for women and men, respectively. The average of the maximum LVMT at the mid-cavity for women/men was 7/9 mm (long axis) and 7/8 mm (short axis). Mean LVMT was positively associated with weight (0.02 mm/kg; P=0.01) and body surface area (1.1 mm/m2; P<0.001). No relationship was found between mean LVMT and age or height. Greater mean LVMT was associated with lower left ventricular end-diastolic volume (0.01 mm/mL; P<0.01), a lower left ventricular end-systolic volume (-0.01 mm/mL; P=0.01), and lower left ventricular stroke volume (-0.01 mm/mL; P<0.05). LVMT measured on long axis images at the basal and mid-cavity level were slightly greater (by 6% and 10%, respectively) than measurements obtained on short axis images; apical LVMT values on long axis images were 20% less than those on short axis images.
July 2012The Road Less Traveled: Importance of the Lesser Branches of the Celiac Axis in Liver Embolotherapy.
Lee AJ, Gomes AS, Liu DM, Kee ST, Loh CT, McWilliams JP.
Effective treatment of unresectable hepatic neoplasms depends on the appropriate identification of tumor arterial supply. Because hepatic tumors derive more than 90% of their blood supply from the hepatic arteries, awareness of common hepatic arterial anatomic variants (eg, replaced or accessory left or right hepatic artery), as well as parasitized collateral vessels originating from the celiac axis (eg, right inferior phrenic, omental, and cystic arteries) that can supply hepatic neoplasms—particularly those with a surface location—is important for safe and effective interventional therapy for these tumors. Moreover, recognition of certain nonhepatic branches arising from the hepatic arterial circulation is important for optimizing transarterial therapy and blocking the passage of treatment particles into sensitive structures, thereby preventing unwanted clinical sequelae such as gastrointestinal ulceration, skin ulceration or pain, and, rarely, ischemic cholecystitis.
July 2012Apparent Diffusion Coefficient Histogram Analysis Stratifies Progression-Free and Overall Survival in Patients with Recurrent GBM Treated with Bevacizumab: a Multi-Center study.
Pope WB, Qiao XJ, Kim HJ, Lai A, Nghiemphu P, Xue X, Ellingson BM, Schiff D, Aregawi D, Cha S, Puduvalli VK, Wu J, Yung WK, Young GS, Vredenburgh J, Barboriak D, Abrey LE, Mikkelsen T, Jain R, Paleologos NA, Rn PL, Prados M, Goldin J, Wen PY, Cloughesy T.
We have tested the predictive value of apparent diffusion coefficient (ADC) histogram analysis in stratifying progression-free survival (PFS) and overall survival (OS) in bevacizumab-treated patients with recurrent glioblastoma multiforme (GBM) from the multi-center BRAIN study. Available MRI's from patients enrolled in the BRAIN study (n = 97) were examined by generating ADC histograms from areas of enhancing tumor on T1 weighted post-contrast images fitted to a two normal distribution mixture curve. ADC classifiers including the mean ADC from the lower curve (ADC-L) and the mean lower curve proportion (LCP) were tested for their ability to stratify PFS and OS by using Cox proportional hazard ratios and the Kaplan-Meier method with log-rank test. Mean ADC-L was 1,209 x 10-6mm2/s ± 224 (SD), and mean LCP was 0.71 ± 0.23 (SD). Low ADC-L was associated with worse outcome. The hazard ratios for 6-month PFS, overall PFS, and OS in patients with less versus greater than mean ADC-L were 3.1 (95 % confidence interval: 1.6, 6.1; P = 0.001), 2.3 (95 % CI: 1.3, 4.0; P = 0.002), and 2.4 (95 % CI: 1.4, 4.2; P = 0.002), respectively. In patients with ADC-L <1,209 and LCP >0.71 versus ADC-L >1,209 and LCP <0.71, there was a 2.28-fold reduction in the median time to progression, and a 1.42-fold decrease in the median OS. The predictive value of ADC histogram analysis, in which low ADC-L was associated with poor outcome, was confirmed in bevacizumab-treated patients with recurrent GBM in a post hoc analysis from the multi-center (BRAIN) study.
July 2012Leukoaraiosis Predicts Parenchymal Hematoma After Mechanical Thrombectomy in Acute Ischemic Stroke.
Shi ZS, Loh Y, Liebeskind DS, Saver JL, Gonzalez NR, Tateshima S, Jahan R, Feng L, Vespa PM, Starkman S, Salamon N, Villablance JP, Ali LK, Ovbiagele B, Kim D, Viñuela F, Duckwiler GR.
BACKGROUND & PURPOSE: The purpose of this study was to determine whether leukoaraiosis (LA) predicts hemorrhagic transformation and poor outcome in patients with acute ischemic stroke treated by mechanical thrombectomy. METHODS: We retrospectively analyzed patients with anterior circulation stroke treated with Merci devices and identified LA in the deep white matter (DWM) and periventricular white matter on the preintervention MR images. We dichotomized patients into those with moderate or severe LA in the DWM versus those without. Hemorrhage rates and outcomes were evaluated between 2 groups. We analyzed the association of moderate or severe LA with hemorrhagic transformation and poor outcome.
June 2012Comparison Between Intensity Normalization Techniques for Dynamic Susceptibility Contrast (DSC)-MRI Estimates of Cerebral Blood Volume (CBV) in Human Gliomas.
Ellingson BM, Zaw T, Cloughesy TF, Naeini KM, Lalezari S, Mong S, Lai A, Nghiemphu PL, Pope WB.
PURPOSE: To compare "standardization," "Gaussian normalization," and "Z-score normalization" intensity transformation techniques in dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) estimates of cerebral blood volume (CBV) in human gliomas. DSC-MRI is a well-established biomarker for CBV in brain tumors; however, DSC-MRI estimates of CBV are semiquantitative. The use of image intensity transformation algorithms provides a mechanism for obtaining quantitatively similar CBV maps with the same intensity scaling. MATERIALS & METHODS: The coefficient of variance (CV) in normal-appearing white matter and relative contrast between tumor regions and normal tissue was compared between the three CBV transformations across five different MR scanners in 96 patients with gliomas.
June 2012Application of Compressed Sensing to Multidimensional Spectroscopic Imaging in Human Prostate
Furuyama JK, Wilson NE, Burns BL, Nagarajan R, Margolis DJ, Thomas MA.
The application of compressed sensing is demonstrated in a recently implemented four-dimensional echo-planar based J-resolved spectroscopic imaging sequence combining two spatial and two spectral dimensions. The echo-planar readout simultaneously acquires one spectral and one spatial dimension. Therefore, the compressed sensing undersampling is performed along the indirectly acquired spatial and spectral dimensions, and the reconstruction is performed using the split Bregman algorithm, an efficient TV-minimization solver. The four- dimensional echo-planar-based J-resolved spectroscopic imaging data acquired in a prostate phantom containing metabolites at physiological concentrations are accurately reconstructed with as little as 20% of the original data. Experimental data acquired in six healthy prostates using the external body matrix "receive" coil on a 3T magnetic resonance imaging scanner are reconstructed with acquisitions using only 25% of the Nyquist-Shannon required amount of data, indicating the potential for a 4-fold acceleration factor in vivo, bringing the required scan time for multidimensional magnetic resonance spectroscopic imaging within clinical feasibility.
June 2012Irreversible Electroporation in Eradication of Rabbit VX2 Liver Tumor.
Lee EW, Wong D, Tafti BA, Prieto V, Totonchy M, Hilton J, Dry S, Cho S, Loh CT, Kee ST.
MATERIALS & METHODS: VX2 liver tumor implantation was performed in 35 New Zealand White Rabbits. The rabbits were divided into three groups 1 week after implantation. The control group included 15 rabbits; the remaining 20 rabbits were divided into two IRE treatment groups. For the treatment groups, 10 rabbits underwent ablation with a single IRE application (IRE-S group), and 10 rabbits underwent ablation with multiple IRE applications (IRE-M group). Treatments and outcomes were analyzed using ultrasound, contrast-enhanced computed tomography (CT), and immunohistologic staining (hematoxylin and eosin [H&E], P-53, Ki-67, CD30, and vascular endothelial growth factor receptor [VEGFR] staining, and terminal deoxynucleotidyl-transferase-mediated 2'-deoxyuridine 5'- triphosphate [dUTP]-biotin nick-end labeling [TUNEL] assay).
June 2012Association of Laterality and Size of Perfusion Lesions on Neurological Deficit in Acute Supratentorial Stroke.
Lee M, Saver JL, Alger JR, Hao Q, Salamon N, Starkman S, Ali LK, Ovbiagele B, Kim D, Villablanca JP, Froehler MT, Tenser MS, Liebeskind DS.
BACKGROUND: The influence of lesion size and laterality on each component of the National Institutes of Health Stroke Scale has not been delineated. The objective of this study was to use perfusion-weighted imaging to characterize the association of ischaemic volume and laterality on each component item and the total score of the National Institutes of Health Stroke Scale. METHODS: We analysed consecutive right-handed patients with first-ever supratentorial acute ischaemic strokes who underwent acute perfusion-weighted imaging at a single centre. Perfusion deficits were defined as mean transit time > 10 s. Ordinal regression was used to clarify the relationship between ischaemic volume, laterality, and National Institutes of Health Stroke Scale scores.
June 2012Anterior Choroidal Artery Ischaemic Patterns Predict Outcome of Carotid Occlusion
Lee M, Saver JL, Hao Q, Starkman S, Salamon N, Ali LK, Kim D, Ovbiagele B, Song S, Raychev R, Abcede H, Fiaz R, Liebeskind DS; for the UCLA Stroke Investigators.
OBJECTIVE: To investigate whether anterior choroidal artery (AChA) territory sparing or AChA infarction restricted to the medial temporal lobe (MT), implying good collateral status, predicts good outcome, defined as modified Rankin Scale 0-2, at discharge in acute internal carotid artery (ICA) occlusion. METHODS: The authors studied consecutive patients with acute ICA occlusion admitted to an academic medical centre between January 2002 and August 2010, who underwent MRI followed by conventional angiography. The pattern of AChA involvement on initial diffusion-weighted imaging was dichotomised as spared or MT only versus other partial or full. The association of AChA infarct patterns and good outcome at discharge was calculated by multivariate logistic regression with adjustment.
June 2012Effects of Perianeurysmal Environment during the Growth of Cerebral Aneurysms: A Case Study
Sforza DM, Putman CM, Tateshima S, Viñuela F, Cebral JR.
BACKGROUND AND PURPOSE: The natural history of cerebral aneurysms is thought to be governed by multifactorial processes involving hemodynamics, biomechanics, mechanobiology, and perianeurysmal environment. The purpose of this study was to highlight the importance of considering the influence of contacts with perianeurysmal environment structures on the hemodynamics and geometric evolution of intracranial aneurysms. MATERIALS AND METHODS: A large aneurysm of the basilar artery in contact with bone and observed to grow during a 4-year follow-up period was selected for study. Anatomic models were constructed from longitudinal CTA images acquired at 1-year intervals during the observation period. Computational fluid dynamics simulations were carried out under pulsatile flow conditions to analyze the blood flow pattern and WSS distribution in the aneurysm during its evolution.
June 2012Mutations in the RNA Exosome Component Gene EXOSC3 Cause Pontocerebellar Hypoplasia and Spinal Motor Neuron Degeneration.
Wan J, Yourshaw M, Mamsa H, Rudnik-Schöneborn S, Menezes MP, Hong JE, Leong DW, Senderek J, Salman MS, Chitayat D, Seeman P, von Moers A, Graul-Neumann L, Kornberg AJ, Castro-Gago M, Sobrido MJ, Sanefuji M, Shieh PB, Salamon N, Kim RC, Vinters HV, Chen Z, Zerres K, Ryan MM, Nelson SF, Jen JC.
RNA exosomes are multi-subunit complexes conserved throughout evolution and are emerging as the major cellular machinery for processing, surveillance and turnover of a diverse spectrum of coding and noncoding RNA substrates essential for viability. By exome sequencing, we discovered recessive mutations in EXOSC3 (encoding exosome component 3) in four siblings with infantile spinal motor neuron disease, cerebellar atrophy, progressive microcephaly and profound global developmental delay, consistent with pontocerebellar hypoplasia type 1 (PCH1; MIM 607596). We identified mutations in EXOSC3 in an additional 8 of 12 families with PCH1. Morpholino knockdown of exosc3 in zebrafish embryos caused embryonic maldevelopment, resulting in small brain size and poor motility, reminiscent of human clinical features, and these defects were largely rescued by co-injection with wild-type but not mutant exosc3 mRNA. These findings represent the first example of an RNA exosome core component gene that is responsible for a human disease and further implicate dysregulation of RNA processing in cerebellar and spinal motor neuron maldevelopment and degeneration.
May 2012Current State-of-the-Art 1.5 T and 3 T Extracranial Carotid Contrast-Enhanced Magnetic Resonance Angiography.
Demarco JK, Willinek WA, Finn JP, Huston J 3rd.
Recent advances in magnetic resonance (MR) hardware and software have improved the resolution and spatial coverage of head and neck first-pass contrast-enhanced (CE) MR angiography. Despite these improvements, high-quality submillimeter-resolution 1.5 T and 3 T carotid CE MR angiography is not consistently available in the general radiology practice. This article reviews the important imaging parameters and potential pitfalls that affect carotid CE MR angiography image quality, and the dose and timing of the gadolinium-based contrast agent, and summarizes vendor-specific protocols for high-quality submillimeter-resolution carotid CE MR angiography at 1.5 and 3 T.
May 2012Trabeculated (Noncompacted) and Compact Myocardium in Adults: the Multi-Ethnic Study of Atherosclerosis.
Kawel N, Nacif M, Arai AE, Gomes AS, Hundley WG, Johnson WC, Prince MR, Stacey RB, Lima JA, Bluemke DA.
A high degree of noncompacted (trabeculated) myocardium in relationship to compact myocardium (trabeculated to compact myocardium [T/M] ratio >2.3) has been associated with a diagnosis of left ventricular noncompaction (LVNC). The purpose of this study was to determine the normal range of the T/M ratio in a large population-based study and to examine the relationship to demographic and clinical parameters. The thickness of trabeculation and the compact myocardium were measured in 8 left ventricular regions on long axis cardiac MR steady-state free precession cine images in 1000 participants (551 women; 68.1±8.9 years) of the Multi-Ethnic Study of Atherosclerosis cohort. Of 323 participants without cardiac disease or hypertension and with all regions evaluable, 140 (43%) had a T/M ratio >2.3 in at least 1 region; in 20 of 323 (6%), T/M >2.3 was present in >2 regions. A multivariable linear regression model revealed no association of age, sex, ethnicity, height, and weight with maximum T/M ratio in participants without cardiac disease or hypertension (P>0.05). In the entire cohort (n=1000), left ventricular ejection fraction (β=-0.02/%; P=0.015), left ventricular end-diastolic volume (β=0.01/mL; P<0.0001), and left ventricular end-systolic volume (β=0.01/mL; P<0.001) were associated with maximum T/M ratio in adjusted models, whereas there was no association with hypertension or myocardial infarction (P>0.05). At the apical level, T/M ratios were significantly lower when obtained on short- compared with long-axis images (P=0.017).
May 2012The Penumbra Stroke System: A Technical Review.
Yoo AJ, Frei D, Tateshima S, Turk AS, Hui FK, Brook AL, Heck DV, Hirsch JA.
Major ischemic strokes secondary to proximal artery occlusions are responsible for significant morbidity and mortality. Owing to extensive clot burden, these strokes are poorly responsive to intravenous tissue plasminogen activator. The introduction of endovascular therapy, particularly mechanical devices, has resulted in markedly improved recanalization rates of large vessel occlusions. With increasing experience with the Penumbra Stroke System and the 054 reperfusion catheter, there has been further improvement in TIMI 2 and 3 revascularization rates with faster times to vessel opening. The aim of this technical review is to convey various tips and tricks learnt from this experience.
April 2012A Combined Pulmonary-Radiology Workshop for Visual Evaluation of COPD: Study Design, Chest CT Findings and Concordance with Quantitative Evaluation.
Barr CC, Berkowitz EA, Bigazzi F, Bode F, Bon J, Bowler RP, Chiles C, Crapo JD, Criner GJ, Curtis JL, Dass C, Dirksen A, Dransfield MT, Edula G, Erikkson L, Friedlander A, Galperin-Aizenberg M, Gefter WB, Gierada DS, Grenier PA, Goldin J, Han MK, Hanania NA, Hansel NN, Jacobson FL, Kauczor HU, Kinnula VL, Lipson DA, Lynch DA, Macnee W, Make BJ, Mamary AJ, Mann H, Marchetti N, Mascalchi M, McLennan G, Murphy JR, Naidich D, Nath H, Newell JD Jr, Pistolesi M, Regan EA, Reilly JJ, Sandhaus R, Schroeder JD, Sciurba F, Shaker S, Sharafkhaneh A, Silverman EK, Steiner RM, Strange C, Sverzellati N, Tashjian JH, Beek EJ, Washington L, Washko GR, Westney G, Wood SA, Woodruff PG.
The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring. Methods: Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9-11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements.
April 2012Computer-Aided Quantitative Bone Scan Assessment of Prostate Cancer Treatment Response.
Brown MS, Chu GH, Kim HJ, Allen-Auerbach M, Poon C, Bridges J, Vidovic A, Ramakrishna B, Ho J, Morris MJ, Larson SM, Scher HI, Goldin JG.
Objective: The development and evaluation of a computer-aided bone scan analysis technique to quantify changes in tumor burden and assess treatment effects in prostate cancer clinical trials. Methods: We have developed and report on a commercial fully automated computer-aided detection (CAD) system. Using this system, scan images were intensity normalized, and then lesions were identified and segmented by anatomic region-specific intensity thresholding. Detected lesions were compared against expert markings to assess the accuracy of the CAD system. The metrics Bone Scan Lesion Area, Bone Scan Lesion Intensity, and Bone Scan Lesion Count were calculated from identified lesions, and their utility in assessing treatment effects was evaluated by analyzing before and after scans from metastatic castration-resistant prostate cancer patients: 10 treated and 10 untreated. In this study, patients were treated with cabozantinib, a MET/vascular endothelial growth factor inhibitor resulting in high rates of resolution of bone scan abnormalities.
April 2012Frequent Detection of Pancreatic Lesions in Asymptomatic High-Risk Individuals.
Canto MI, Hruban RH, Fishman EK, Kamel IR, Schulick R, Zhang Z, Topazian M, Takahashi N, Fletcher J, Petersen G, Klein AP, Axilbund J, Griffin C, Syngal S, Saltzman JR, Mortele KJ, Lee J, Tamm E, Vikram R, Bhosale P, Margolis D, Farrell J, Goggins M; American Cancer of the Pancreas Screening (CAPS) Consortium.
The risk of pancreatic cancer is increased in patients with a strong family history of pancreatic cancer or a predisposing germline mutation. Screening can detect curable, noninvasive pancreatic neoplasms, but the optimal imaging approach is not known. We determined the baseline prevalence and characteristics of pancreatic abnormalities using 3 imaging tests to screen asymptomatic, high-risk individuals (HRIs). We screened 225 asymptomatic adult HRIs at 5 academic US medical centers once, using computed tomography (CT), magnetic resonance imaging (MRI), and endoscopic ultrasonography (EUS). We compared results in a blinded, independent fashion.
April 2012Radiology's Value Chain.
A diagnostic radiology value chain is constructed to define its main components, all of which are vulnerable to change, because digitization has caused disaggregation of the chain. Some components afford opportunities to improve productivity, some add value, while some face outsourcing to lower labor cost and to information technology substitutes, raising commoditization risks. Digital image information, because it can be competitive at smaller economies of scale, allows faster, differential rates of technological innovation of components, initiating a centralization-to-decentralization technology trend. Digitization, having triggered disaggregation of radiology's professional service model, may soon usher in an information business model. This means moving from a mind-set of "reading images" to an orientation of creating and organizing information for greater accuracy, faster speed, and lower cost in medical decision making. Information businesses view value chain investments differently than do small professional services. In the former model, producing a better business product will extend image interpretation beyond a radiologist's personal fund of knowledge to encompass expanding external imaging databases. A follow-on expansion with integration of image and molecular information into a report will offer new value in medical decision making. Improved interpretation plus new integration will enrich and diversify radiology's key service products, the report and consultation. A more robust, information-rich report derived from a "systems" and "computational" radiology approach will be facilitated by a transition from a professional service to an information business. Under health care reform, radiology will transition its emphasis from volume to greater value. Radiology's future brightens with the adoption of a philosophy of offering information rather than "reads" for decision making. Staunchly defending the status quo via turf wars is unlikely to constitute a forward-looking, competitive strategy.
April 2012In vitro and in vivo Testing of a Novel, Hyperelastic Thin Film Nitinol Flow Diversion Stent
Kealey CP, Chun YJ, Viñuela FE, Mohanchandra KP, Carman GP, Viñuela F, Levi DS.
A flexible, low profile, flow diversion stent could replace endovascular coiling for the treatment of intracranial aneurysms. Micropatterned-thin film nitinol (TFN) is a novel biomaterial with high potential for use in next-generation endovascular devices. Recent advancements in micropatterning have allowed for fabrication of a hyperelastic thin film nitinol (HE-TFN). In this study, the authors describe in vitro and in vivo testing of novel HE-TFN based flow diverting stents. Two types of HE-TFN with expanded pores having long axes of 300 and 500 μm were used to fabricate devices. In vitro examination of the early thrombotic response in whole blood showed a possible mechanism for the device's function, whereby HE-TFN serves as a scaffold for blood product deposition. In vivo testing in swine demonstrated rapid occlusion of model wide-neck aneurysms. Average time to occlusion for the 300-μm device was 10.4 ± 5.5 min. (N = 5) and 68 ± 30 min for the 500-μm device (N = 5). All aneurysms treated with bare metal control stents remained patent after 240 min (N = 3). SEM of acutely harvested devices supported in vitro results, demonstrating that HE-TFN serves as a scaffold for blood product deposition, potentially enhancing its flow-diverting effect. Histopathology of devices after 42 days in vivo demonstrated a healthy neointima and endothelialization of the aneurysm neck region. HE-TFN flow-diverting stents warrant further investigation as a novel treatment for intracranial aneurysms.a
April 2012Transvenous Creation of a Mesocaval Shunt: Report of Use in the Management of Extrahepatic Portal Vein Occlusion.
Moriarty JM, Kokabi N, Kee ST.
The creation of a transjugular intrahepatic portosystemic shunt (TIPS) has become a standard procedure for the treatment of variceal hemorrhage in the setting of portal hypertension (1). However, TIPS ...
April 2012Relevance of Compartmental Anatomic Guidelines for Biopsy of Musculoskeletal Tumors: Retrospective Review of 363 Biopsies over a 6-Year Period.
Uybico SJ, Motamedi K, Omura MC, Nelson SD, Eilber FC, Eckardt J, Seeger LL.
Purpose: To retrospectively assess percutaneous core needle biopsies performed by radiologists and the association with tumor seeding along the biopsy tract when anatomic compartment guidelines are not consistently observed. Materials and Methods: Retrospective data from computerized patient records and digital images from 363 consecutive computed tomography-guided biopsies of the lower extremity (thigh and leg) performed by radiologists at a single institution from August 2002 to August 2008 were analyzed for breaches of biopsy guidelines.
April 2012The Value of Arterial Spin-Labeled Perfusion Imaging in Acute Ischemic Stroke: Comparison With Dynamic Susceptibility Contrast-Enhanced MRI
Wang DJ, Alger JR, Qiao JX, Hao Q, Hou S, Fiaz R, Gunther M, Pope WB, Saver JL, Salamon N, Liebeskind DS; UCLA Stroke Investigators.
The purpose of this study was to evaluate the potential clinical value of arterial spin-labeled (ASL) perfusion MRI in acute ischemic stroke (AIS) through comparison with dynamic susceptibility contrast (DSC) enhanced perfusion MRI. Pseudocontinuous ASL with 3-dimensional background-suppressed gradient and spin echo readout was applied with DSC perfusion MRI on 26 patients with AIS. ASL cerebral blood flow and multiparametric DSC perfusion maps were rated for image quality and lesion severity/conspicuity. Mean ASL cerebral blood flow and DSC perfusion values were obtained in main vascular territories. Kendall coefficient of concordance was calculated to evaluate the reliability of ratings. Spearman correlation coefficients were calculated to compare ratings and quantitative perfusion values between ASL and DSC perfusion maps.
April 2012The Impact of Thromboemboli Histology on the Performance of a Mechanical Thrombectomy Device
Yuki I, Kan I, Vinters HV, Kim RH, Golshan A, Viñuela FA, Sayre JW, Murayama Y, Viñuela F.
BACKGROUND AND PURPOSE: Recently we published a novel method of thrombus preparation for use in a swine model for evaluation of thrombectomy designs. The clot (fibrin rich clot) is characterized by its similarity in histologic characteristics to the thromboemboli recovered from stroke patients. The purpose of this latest study was to evaluate if the performance of a mechanical thrombectomy device was affected by the histologic characteristics of thromboembolus. Erythrocyte rich clot, which was created using exogenous thrombin, and the novel experimental clot with abundance of fibrin/cellular component were used for comparison. The Merci clot retriever was used for the evaluation and the angiographic outcomes were analyzed. MATERIALS AND METHODS: Two histologically different types of experimental clot, a conventionally used thrombin-induced clot (erythrocyte-rich clot) and a novel experimental clot that is similar in histologic characteristics to the thromboemboli recovered from patients with stroke (fibrin-rich clot), were prepared. Eight extracranial arteries in swine were occluded with erythrocyte-rich clot (group A), and 8 were occluded with fibrin-rich clot (group B), and MT by using the Merci clot retriever device was performed. Angiographic results in each group were evaluated.
March 2012Migration of Intrauterine Devices: Radiologic Findings and Implications for Patient Care.
Boortz HE, Margolis DJ, Ragavendra N, Patel MK, Kadell BM.
Intrauterine devices (IUDs) are a commonly used form of contraception worldwide. However, migration of the IUD from its normal position in the uterine fundus is a frequently encountered complication, varying from uterine expulsion to displacement into the endometrial canal to uterine perforation. Different sites of IUD translocation vary in terms of their clinical significance and subsequent management, and the urgency of communicating IUD migration to the clinician is likewise variable. Expulsion or intrauterine displacement of the IUD leads to decreased contraceptive efficacy and should be clearly communicated, since it warrants IUD replacement to prevent unplanned pregnancy. Embedment of the IUD into the myometrium can usually be managed in the outpatient clinical setting but occasionally requires hysteroscopic removal. Complete uterine perforation, in which the IUD is partially or completely within the peritoneal cavity, requires surgical management, and timely and direct communication with the clinician is essential in such cases. Careful evaluation for intraabdominal complications is also important, since they may warrant urgent or emergent surgical intervention. The radiologist plays an important role in the diagnosis of IUD migration and should be familiar with its appearance at multiple imaging modalities.
March 2012Functional Diffusion Maps (fDMs) Evaluated Before and After Radiochemotherapy Predict Progression-Free and Overall Survival in Newly Diagnosed Glioblastoma.
Ellingson BM, Cloughesy TF, Zaw T, Lai A, Nghiemphu PL, Harris R, Lalezari S, Wagle N, Naeini KM, Carrillo J, Liau LM, Pope WB.
Functional diffusion mapping (fDM) has shown promise as a sensitive imaging biomarker for predicting survival in initial studies consisting of a small number of patients, mixed tumor grades, and before routine use of anti-angiogenic therapy. The current study tested whether fDM performed before and after radiochemotherapy could predict progression-free and overall survival in 143 patients with newly diagnosed glioblastoma from 2007 through 2010, many treated with anti-angiogenic therapy after recurrence. Diffusion and conventional MRI scans were obtained before and 4 weeks after completion of radiotherapy and concurrent temozolomide treatment. FDM was created by coregistering pre- and posttreatment apparent diffusion coefficient (ADC) maps and then performing voxel-wise subtraction. FDMs were categorized according to the degree of change in ADC in pre- and posttreatment fluid-attenuated inversion recovery (FLAIR) and contrast-enhancing regions. The volume fraction of fDM-classified increasing ADC(+), decreasing ADC(), and change in ADC(+/) were tested to determine whether they were predictive of survival. Both Bonferroni-corrected univariate log-rank analysis and Cox proportional hazards modeling demonstrated that patients with decreasing ADC in a large volume fraction of pretreatment FLAIR or contrast-enhancing regions were statistically more likely to progress earlier and expire sooner than in patients with a lower volume fraction. The current study supports the hypothesis that fDM is a sensitive imaging biomarker for predicting survival in glioblastoma.
March 2012ACR Appropriateness Criteria® Acute Respiratory Illness in Immunocompromised Patients.
Heitkamp DE, Mohammed TL, Kirsch J, Amorosa JK, Brown K, Chung JH, Dyer DS, Ginsburg ME, Kanne JP, Kazerooni EA, Ketai LH, Parker JA, Ravenel JG, Saleh AG, Shah RD.
The respiratory system is often affected by complications of immunodeficiency, typically manifesting clinically as acute respiratory illness. Ongoing literature reviews regarding the appropriateness of imaging in these patients are critical, as advanced medical therapies such as stem cell transplantation, chemotherapy, and immunosuppressive therapies for autoimmune disease continue to keep high the population of immunosuppressed patients in our health care system today. This ACR Appropriateness Criteria® topic describes clinical scenarios of acute respiratory illness in immunocompromised patients with cough, dyspnea, chest pain, and fever; in those with negative, equivocal, or nonspecific findings on chest radiography; in those with diffuse or confluent opacities on chest radiography; and in those in whom noninfectious disease is suspected. The use of chest radiography, chest CT, transthoracic needle biopsy, and nuclear medicine imaging are all discussed in the contexts of these clinical scenarios. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
March 2012A Call to Action: Women and Peripheral Artery Disease: A Scientific Statement From the American Heart Association.
Hirsch AT, Allison MA, Gomes AS, Corriere MA, Duval S, Ershow AG, Hiatt WR, Karas RH, Lovell MB, McDermott MM, Mendes DM, Nussmeier NA, Treat-Jacobson D; on behalf of the American Heart Association Council on Peripheral Vascular Disease; Council on Cardiovascular Nursing; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Surgery and Anesthesia; Council on Clinical Cardiology; Council on Epidemiology and Prevention.
Lower extremity atherosclerotic peripheral artery disease (PAD) has a very high prevalence in most nations and in the United States.1-8 Lower extremity PAD is now known to be associated with equal morbidity and mortality and comparable (or higher) health economic costs as coronary heart disease (CHD) and ischemic stroke.9,10 Yet where surveyed, the public and clinicians (as well as health payers and government agencies) do not yet fully recognize the risks associated with PAD.11 For decades, clinicians did not recognize the impact of coronary disease in women.12 As such, women were not informed of their CHD risk. For any common disease, whether infectious, oncological, or traumatic, when more than half of the population at risk is not aware of this risk, and when this risk is not managed, preventable morbid and mortal events are inevitable. Certain health facts are now evident: Women suffer the consequences of PAD at rates at least as high as those observed in men. But major knowledge gaps exist. Clinical research to evaluate gender-based differences that might underlie the delayed, postmenopausal presentation of PAD in women has not been conducted. Whether subtle but important gender-based distinctions in clinical presentations exist is unknown. The relative sensitivity and specificity of PAD diagnostic tests and pathways by gender are unclear. Although there is suggestive evidence that treatment benefits and harms are different in women and men, this cannot yet be confirmed from current clinical trial data because of the limited inclusion...
March 2012Context-Based Electronic Health Record: Toward Patient Specific Healthcare.
Hsu W, Taira RK, El-Saden S, Kangarloo H, Bui AA.
Due to the increasingly data-intensive clinical environment, physicians now have unprecedented access to detailed clinical information from a multitude of sources. However, applying this information to guide medical decisions for a specific patient case remains challenging. One issue is related to presenting information to the practitioner: displaying a large (irrelevant) amount of information often leads to information overload. Next-generation interfaces for the electronic health record (EHR) should not only make patient data easily searchable and accessible, but also synthesize fragments of evidence documented in the entire record to understand the etiology of a disease and its clinical manifestation in individual patients. In this paper, we describe our efforts toward creating a context-based EHR, which employs biomedical ontologies and (graphical) disease models as sources of domain knowledge to identify relevant parts of the record to display. We hypothesize that knowledge (e.g., variables, relationships) from these sources can be used to standardize, annotate, and contextualize information from the patient record, improving access to relevant parts of the record and informing medical decision making. To achieve this goal, we describe a framework that aggregates and extracts findings and attributes from free-text clinical reports, maps findings to concepts in available knowledge sources, and generates a tailored presentation of the record based on the information needs of the user. We have implemented this framework in a system called Adaptive EHR, demonstrating its capabilities to present and synthesize information from neurooncology patients. This paper highlights the challenges and potential applications of leveraging disease models to improve the access, integration, and interpretation of clinical patient data.
March 2012Use of MR Imaging to Determine Preservation of the Neurovascular Bundles at Robotic-assisted Laparoscopic Prostatectomy.
McClure TD, Margolis DJ, Reiter RE, Sayre JW, Thomas MA, Nagarajan R, Gulati M, Raman SS.
The purpose of this study is to determine whether findings at preoperative endorectal coil magnetic resonance (MR) imaging influence the decision to preserve neurovascular bundles and the extent of surgical margins in robotic-assisted laparoscopic prostatectomy (RALP). This study was approved by the investigational review board and was compliant with the HIPAA; the requirement to obtain informed consent was waived. The authors prospectively evaluated 104 consecutive men with biopsy-proved prostate cancer who underwent preoperative endorectal coil MR imaging of the prostate and subsequent RALP. MR imaging was performed at 1.5 T between January 2004 and April 2008 and included T2-weighted imaging (n = 104), diffusion-weighted imaging (n = 88), dynamic contrast-enhanced imaging (n = 51), and MR spectroscopy (n = 91). One surgeon determined the planned preoperative extent of resection bilaterally on the basis of clinical information and then again after review of the final MR imaging report. The differences in the surgical plan before and after review of the MR imaging report were determined and compared with the actual surgical and pathologic results by using logistic regression analysis. Continuous and ranked variables underwent Pearson and Spearman analysis.
March 2012Non-Invasive Detection of 2-Hydroxyglutarate and Other Metabolites in IDH1 Mutant Glioma Patients Using Magnetic Resonance Spectroscopy.
Pope WB, Prins RM, Albert Thomas M, Nagarajan R, Yen KE, Bittinger MA, Salamon N, Chou AP, Yong WH, Soto H, Wilson N, Driggers E, Jang HG, Su SM, Schenkein DP, Lai A, Cloughesy TF, Kornblum HI, Wu H, Fantin VR, Liau LM.
Mutations of the isocitrate dehydrogenase 1 and 2 genes (IDH1 and IDH2) are commonly found in primary brain cancers. We previously reported that a novel enzymatic activity of these mutations results in the production of the putative oncometabolite, R(-)-2-hydroxyglutarate (2-HG). Here we investigated the ability of magnetic resonance spectroscopy (MRS) to detect 2-HG production in order to non-invasively identify patients with IDH1 mutant brain tumors. Patients with intrinsic glial brain tumors (n = 27) underwent structural and spectroscopic magnetic resonance imaging prior to surgery. 2-HG levels from MRS data were quantified using LC-Model software, based upon a simulated spectrum obtained from a GAMMA library added to the existing prior knowledge database. The resected tumors were then analyzed for IDH1 mutational status by genomic DNA sequencing, Ki-67 proliferation index by immunohistochemistry, and concentrations of 2-HG and other metabolites by liquid chromatographymass spectrometry (LCMS). MRS detected elevated 2-HG levels in gliomas with IDH1 mutations compared to those with wild-type IDH1 (P = 0.003). The 2-HG levels measured in vivo with MRS were significantly correlated with those measured ex vivo from the corresponding tumor samples using LCMS (r 2 = 0.56; P = 0.0001). Compared with wild-type tumors, those with IDH1 mutations had elevated choline (P = 0.01) and decreased glutathione (P = 0.03) on MRS. Among the IDH1 mutated gliomas, quantitative 2-HG values were correlated with the Ki-67 proliferation index of the tumors (r2 = 0.59; P = 0.026). In conclusion, water-suppressed proton (1H) MRS provides a non-invasive measure of 2-HG in gliomas, and may serve as a potential biomarker for patients with IDH1 mutant brain tumors. In addition to 2-HG, alterations in several other metabolites measured by MRS correlate with IDH1 mutation status.
March 2012Fourier Analysis of STimulated Echoes (FAST) for the Quantitative Analysis of Left Ventricular Twist.
Reyhan M, Natsuaki Y, Ennis DB.
The purpose of this study is to validate a novel method for the rapid and facile quantification of left ventricular (LV) twist from tagged magnetic resonance images and demonstrate the potential clinical utility in a series of 20 healthy volunteers. Cardiac magnetic resonance imaging (MRI) short-axis images were acquired with tissue tagging in 20 healthy subjects and six canines. The tagged images were processed using a novel Fourier Analysis of the STimulated echoes (FAST) method, which uses a series of Fourier-space operations to measure LV twist with limited user interaction. A subset of eight healthy subjects and the canine data were compared to results from previously validated gold standard software (FindTags). Interobserver and intraobserver coefficients of variation (CVINTER and CVINTRA), linear regression, and BlandAltman analyses were used to assess agreement between observers and methods.
March 2012Is There a Need for Dedicated Bone Imaging in Addition to 18F-FDG PET/CT Imaging in Pediatric Sarcoma Patients?
Walter F, Czernin J, Hall T, Allen-Auerbach M, Walter MA, Dunkelmann S, Federman N.
Purpose: Many children with sarcomas undergo whole body 2-deoxy-2-(18F)fluoro-D-glucose positron emission tomography / computed tomography (18F-FDG PET/CT) and technetium methylene diphosphonate (99Tc-MDP) studies. It is unknown whether the combination of both tests results in more accurate detection of bone lesions than 18F-FDG- PET/CT alone.
Methods: 99Tc-MDP bone and 18F-FDG PET/CT scans were each read by 2 "blinded" observers and then reviewed side-by-side by 3 readers. Bone lesions were graded qualitatively on a 5-point scale (from benign to malignant). Clinical and imaging follow-up (n=21) and bone biopsy results (n=8) served as reference standard.
March 2012Thrombus Branching and Vessel Curvature are Important Determinants of Middle Cerebral Artery Trunk Recanalization with MERCI Thrombectomy Devices.
Zhu L, Liebeskind DS, Jahan R, Starkman S, Salamon N, Duckwiler G, Viñuela F, Tateshima S, Gonzalez N, Villablanca P, Ali LK, Kim D, Ovbiagele B, Froehler M, Tenser M, Saver JL.
Determinants of successful recanalization likely differ for Merci thrombectomy and intra-arterial pharmacological fibrinolysis interventions. Although the amount of thrombotic material to be digested is an important consideration for chemical lysis, mechanical debulking may be more greatly influenced by other target lesion characteristics. In consecutive patients with acute ischemic stroke treated with Merci thrombectomy for middle cerebral artery M1 occlusions, we analyzed the influence on recanalization success and clinical outcome of target thrombus size (length) and shape (curvature and branching) on pretreatment T2* gradient echo MRI.
February 2012Reproducibility of Volume and Densitometric Measures of Emphysema on Repeat Computed Tomography With an Interval of 1 Week.
Chong D, Brown MS, Kim HJ, van Rikxoort EM, Guzman L, McNitt-Gray MF, Khatonabadi M, Galperin-Aizenberg M, Coy H, Yang K, Jung Y, Goldin JG.
The reproducibilities of CT lung volume and densitometric measures of emphysema were assessed over 1 week. The influence of breathhold on reproducibility was assessed. HRCT was performed on 44 subjects at inspiration on two visits with a 7-day interval. CT lung volume, relative area below -950HU (RA950-raw), and 15th percentile density (PD15-raw) were computed. Volume correction was used to obtain RA950-adj and PD15-adj. Reproducibilities between visits were assessed using concordance correlation coefficient (CCC) and repeatability coefficient (RC). Reproducibilities were compared between raw and adjusted measures. Differences between visits were computed for volume and density measures. Correlations were computed for density differences versus volume difference. Subgroup analysis was performed using a 0.25 L volume difference threshold.
February 2012Development of a Research Agenda for the Management of Metastatic Colorectal Cancer: Proceedings from a Multidisciplinary Research Consensus Panel
Janne d'Othe B, Sofocleous CT, Hanna N, Lewandowski RJ, Soulen MC, Vauthey JN, Cohen SJ, Venook AP, Johnson MS, Kennedy AS, Murthy R, Geschwind JF, Kee ST.
Colorectal cancer (CRC), the second leading cause of cancer death in the United States, occurs in an estimated more than 145,000 patients annually, with almost 50,000 deaths each year. Metastatic live...
February 2012Blood—Brain Barrier Permeability Derangements in Posterior Circulation Ischemic Stroke: Frequency and Relation to Hemorrhagic Transformation.
Lee M, Saver JL, Alger JR, Hao Q, Starkman S, Ali LK, Kim D, Ovbiagele B, Vespa PM, Froehler MT, Tenser MS, Salamon N, Villablanca JP, Jahan R, Duckwiler GR, Tateshima S, Gonzalez N, Viñuela F, Liebeskind DS.
Early disruption of the blood—brain barrier (BBB) due to severe ischemia can be detected by MRI T2* permeability imaging. In middle cerebral artery (MCA) infarction, pretreatment T2* permeability derangements have been found in 22% of patients and are powerful predictors of hemorrhagic transformation after revascularization therapy. The frequency, clinical correlates, and relation to hemorrhagic transformation of permeability derangements in posterior circulation have not been previously explored, and may differ as ischemia volume and collateral status are different between vertebrobasilar and MCA infarcts. We analyzed clinical and pretreatment MRI data on consecutive patients undergoing recanalization therapy for acute vertebrobasilar ischemia at a medical center November 2001 through September 2009. Pretreatment MRI permeability images were derived from perfusion source imaging acquisitions. Permeability abnormality was detected as persisting increased signal intensity at later time points in perfusion MRI acquisition, indicating local accumulation of contrast caused by BBB leakage.
February 2012CFD and PIV Analysis of Hemodynamics in a Growing Intracranial Aneurysm.
Raschi M, Mut F, Byrne G, Putman CM, Tateshima S, Viñuela F, Tanoue T, Tanishita K, Cebral JR.
Hemodynamics is thought to be a fundamental factor in the formation, progression, and rupture of cerebral aneurysms. Understanding these mechanisms is important to improve their rupture risk assessment and treatment. In this study, we analyze the blood flow field in a growing cerebral aneurysm using experimental particle image velocimetry (PIV) and computational fluid dynamics (CFD) techniques. Patient-specific models were constructed from longitudinal 3D computed tomography angiography images acquired at 1-y intervals. Physical silicone models were constructed from the computed tomography angiography images using rapid prototyping techniques, and pulsatile flow fields were measured with PIV. Corresponding CFD models were created and run under matching flow conditions. Both flow fields were aligned, interpolated, and compared qualitatively by inspection and quantitatively by defining similarity measures between the PIV and CFD vector fields. Results showed that both flow fields were in good agreement. Specifically, both techniques provided consistent representations of the main intra-aneurysmal flow structures and their change during the geometric evolution of the aneurysm. Despite differences observed mainly in the near wall region, and the inherent limitations of each technique, the information derived is consistent and can be used to study the role of hemodynamics in the natural history of intracranial aneurysms.
February 2012A Method for the Automatic Quantification of the Completeness of Pulmonary Fissures: Evaluation in a Database of Subjects with Severe Emphysema.
van Rikxoort EM, Goldin JG, Galperin-Aizenberg M, Abtin F, Kim HJ, Lu P, van Ginneken B, Shaw G, Brown MS.
The objectives of this study is to propose and evaluate a technique for automatic quantification of fissural completeness from chest computed tomography (CT) in a database of subjects with severe emphysema. Ninety-six CT studies of patients with severe emphysema were included. The lungs, fissures and lobes were automatically segmented. The completeness of the fissures was calculated as the percentage of the lobar border defined by a fissure. The completeness score of the automatic method was compared with a visual consensus read by three radiologists using boxplots, rank sum tests and ROC analysis.
February 2012Peak Skin and Eye Lens Radiation Dose From Brain Perfusion CT Based on Monte Carlo Simulation.
Zhang D, Cagnon CH, Villablanca JP, McCollough CH, Cody DD, Stevens DM, Zankl M, Demarco JJ, Turner AC, Khatonabadi M, McNitt-Gray MF.
The purpose of our study was to accurately estimate the radiation dose to skin and the eye lens from clinical CT brain perfusion studies, investigate how well scanner output (expressed as volume CT dose index [CTDIvol]) matches these estimated doses, and investigate the efficacy of eye lens dose reduction techniques. Peak skin dose and eye lens dose were estimated using Monte Carlo simulation methods on a voxelized patient model and 64-MDCT scanners from four major manufacturers. A range of clinical protocols was evaluated. CTDIvol for each scanner was obtained from the scanner console. Dose reduction to the eye lens was evaluated for various gantry tilt angles as well as scan locations.
January 2012Improved Left Ventricular Mass Quantification with Partial Voxel Interpolation: in vivo and Necropsy Validation of a Novel Cardiac MRI Segmentation Algorithm.
Codella NC, Lee HY, Fieno DS, Chen DW, Hurtado-Rua S, Kochar M, Finn JP, Judd R, Goyal P, Schenendorf J, Cham MD, Devereux RB, Prince M, Wang Y, Weinsaft JW.
Cardiac magnetic resonance (CMR) typically quantifies LV mass (LVM) by means of manual planimetry (MP), but this approach is time-consuming and does not account for partial voxel components myocardium admixed with blood in a single voxel. Automated segmentation (AS) can account for partial voxels, but this has not been used for LVM quantification. This study used automated CMR segmentation to test the influence of partial voxels on quantification of LVM. LVM was quantified by AS and MP in 126 consecutive patients and 10 laboratory animals undergoing CMR. AS yielded both partial voxel (ASPV) and full voxel (ASFV) measurements. Methods were independently compared with LVM quantified on echocardiography (echo) and an ex vivo standard of LVM at necropsy.
January 2012Quantification of Edema Reduction Using Differential Quantitative T2 (DQT2) Relaxometry Mapping in Recurrent Glioblastoma Treated with Bevacizumab.
Ellingson BM, Cloughesy TF, Lai A, Nghiemphu PL, Lalezari S, Zaw T, Motevalibashinaeini K, Mischel PS, Pope WB.
The purpose of the current study was to quantify the reduction in T2 signal abnormality accompanying administration of the anti- angiogenic drug bevacizumab in recurrent glioblastoma (GBM) patients using a voxel-wise differential quantitative T2 (DQT2) mapping technique. Twenty-six patients with recurrent GBM treated with bevacizumab were scanned before and 46 weeks after treatment on a 1.5T clinical MR scanner. Quantitative T2 maps were created from proton density and T2-weighted images acquired using a standard multi-echo fast-spin echo sequence. T2 maps after treatment were co-registered with T2 maps prior to treatment in the same patient, and then voxel-wise subtraction was performed to create DQT2 maps for each patient. Results suggest DQT2 maps allow visualization and quantification of voxel-wise T2 changes resulting from anti-VEGF therapy. Results demonstrated a significant decrease in T2 within pre-treatment T2 abnormal regions (mean reduction = 49.4 ms at 1.5T) following anti-VEGF treatment (Wilcoxon signed rank test, P < 0.0001). An elevated residual, post-treatment, median T2 was predictive of both progression-free (Log-rank, P = 0.0074) and overall survival (Log-rank, P = 0.0393).
January 2012Anatomic Localization of O6-Methylguanine DNA Methyltransferase (MGMT) Promoter Methylated and Unmethylated Tumors: A Radiographic Study in 358 de novo Human Glioblastomas.
Ellingson BM, Cloughesy TF, Pope WB, Zaw TM, Phillips H, Lalezari S, Nghiemphu PL, Ibrahim H, Naeini KM, Harris RJ, Lai A.
Promoter methylation of O6-methylguanine DNA methyltransferase (MGMT) is associated with a favorable prognosis in glioblastoma multiforme (GBM) and has been hypothesized to occur early in tumor transformation of glial cells. Thus, a possible link exists between the site of malignant transformation and MGMT promoter methylation status. Using the Analysis of Differential Involvement (ADIFFI) statistical mapping technique in a total of 358 patients with GBM, we demonstrate that human de novo GBMs occur in a high frequency contiguous with the posterior subventricular zone (SVZ); MGMT promoter methylated GBMs are lateralized to the left hemisphere, while MGMT unmethylated GBMs are lateralized to the right hemisphere; and tumors near the left temporal lobe have a significantly longer overall survival compared with tumors occurring elsewhere, independent of treatment or MGMT methylation status.
January 2012International Association for the Study of Lung Cancer Computed Tomography Screening Workshop 2011 Report.
Field JK, Smith RA, Aberle DR, Oudkerk M, Baldwin DR, Yankelevitz D, Pedersen JH, Swanson SJ, Travis WD, Wisbuba II, Noguchi M, Mulshine JL; IASLC CT Screening Workshop 2011 Participants.
The International Association for the Study of Lung Cancer (IASLC) Board of Directors convened a computed tomography (CT) Screening Task Force to develop an IASLC position statement, after the National Cancer Institute press statement from the National Lung Screening Trial showed that lung cancer deaths fell by 20%. The Task Force's Position Statement outlined a number of the major opportunities to further improve the CT screening in lung cancer approach, based on experience with cancer screening from other organ sites. The IASLC CT Screening Workshop 2011 further developed these discussions, which are summarized in this report. The recommendation from the workshop, and supported by the IASLC Board of Directors, was to set up the Strategic CT Screening Advisory Committee (IASLC-SSAC). The Strategic CT Screening Advisory Committee is currently engaging professional societies and organizations who are stakeholders in lung cancer CT screening implementation across the globe, to focus on delivering guidelines and recommendations in six specific areas: (i) identification of high-risk individuals for lung cancer CT screening programs; (ii) develop radiological guidelines for use in developing national screening programs; (iii) develop guidelines for the clinical work-up of indeterminate nodules resulting from CT screening programmers; (iv) guidelines for pathology reporting of nodules from lung cancer CT screening programs; (v) recommendations for surgical and therapeutic interventions of suspicious nodules identified through lung cancer CT screening programs; and (vi) integration of smoking cessation practices into future national lung cancer CT screening programs.
January 2012Contribution of Myocardium Overlying the Anterolateral Papillary Muscle to Left Ventricular Deformation.
Itoh A, Stephens EH, Ennis DB, Carlhall CJ, Bothe W, Nguyen TC, Swanson JC, Miller DC, Ingels NB Jr.
Previous studies of transmural left ventricular (LV) strains suggested that the myocardium overlying the papillary muscle displays decreased deformation relative to the anterior LV free wall or significant regional heterogeneity. These comparisons, however, were made using different hearts. We sought to extend these studies by examining three equatorial LV regions in the same heart during the same heartbeat. Therefore, deformation was analyzed from transmural beadsets placed in the equatorial LV myocardium overlying the anterolateral papillary muscle (PAP), as well as adjacent equatorial LV regions located more anteriorly (ANT) and laterally (LAT). We found that the magnitudes of LAT normal longitudinal and radial strains, as well as major principal strains, were less than ANT, while those of PAP were intermediate. Subepicardial and midwall myofiber angles of LAT, PAP, and ANT were not significantly different, but PAP subendocardial myofiber angles were significantly higher (more longitudinal as opposed to circumferential orientation). Subepicardial and midwall myofiber strains of ANT, PAP, and LAT were not significantly different, but PAP subendocardial myofiber strains were less. Transmural gradients in circumferential and radial normal strains, and major principal strains, were observed in each region. The two main findings of this study were as follows: 1) PAP strains are largely consistent with adjacent LV equatorial free wall regions, and 2) there is a gradient of strains across the anterolateral equatorial left ventricle despite similarities in myofiber angles and strains. These findings point to graduated equatorial LV heterogeneity and suggest that regional differences in myofiber coupling may constitute the basis for such heterogeneity.
January 2012Electron Microscopic Demonstration and Evaluation of Irreversible Electroporation-Induced Nanopores on Hepatocyte Membranes.
Lee EW, Wong D, Prikhodko SV, Perez A, Tran C, Loh CT, Kee ST.
The purpose of this study is to demonstrate, evaluate, and verify the existence of irreversible electroporation (IRE)ablation induced nanopores on the plasma membrane of hepatocytes. On animal research committee approval, four New Zealand rabbits and two Yorkshire swine underwent IRE ablation of the liver (90 pulses, 100 s per pulse at 2,500 V), and selected ablated liver tissues were harvested, fixed, and air-dried according to the electron microscopy (EM) protocol. A scanning electron microscope (SEM; Nova 230 NanoSEM [FEI, Hillsboro, Oregon] with 80 picoamperes and 10-kV acceleration) was used to visualize and verify IRE-created nanopores. Using NIH image (Bethesda, Maryland) and ImageScope (Aperio Inc., Vista, California), 21 ablated tissues (16 rabbit, 5 swine) were evaluated. Corresponding hematoxylin and eosin (H&E) evaluation was performed to verify IRE-induced cell death.
January 2012MRSI Correlates of Cognitive-Behavioral Therapy in Pediatric Obsessive-Compulsive Disorder.
O'Neill J, Piacentini JC, Chang S, Levitt JG, Rozenman M, Bergman L, Salamon N, Alger JR, McCracken JT.
The brain mechanisms of cognitivebehavioral therapy (CBT), a highly effective treatment for pediatric obsessive-compulsive disorder (OCD), are unknown. Neuroimaging in adult OCD indicates that CBT is associated with metabolic changes in striatum, thalamus, and anterior cingulate cortex. We therefore probed putative metabolic effects of CBT on these brain structures in pediatric OCD using proton magnetic resonance spectroscopic imaging (1H MRSI). Five unmedicated OCD patients (4 ♀, 13.5 ± 2.8) and 9 healthy controls (7 ♀, 13.0 ± 2.5) underwent MRSI (1.5 T, repetition-time/echo-time = 1500/30 ms) of bilateral putamen, thalamus and pregenual anterior cingulate cortex (pACC). Patients were rescanned after 12 weeks of exposure-based CBT. The Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) of OCD symptoms was administered before and after CBT.
January 2012Cholelithiasis and Its Complications in Children and Adolescents: Update and Case Discussion.
Poffenberger CM, Gausche-Hill M, Ngai S, Myers A, Renslo R.
In recent years, gallbladder disease, primarily in the form of cholelithiasis, has been on the rise among infants and children. Although pediatric gallbladder disease is still less prevalent than adult gallbladder disease, physicians and other clinicians who care for children need to be aware of this underappreciated problem and understand the manifestations of biliary disease in the pediatric population. In this article, case discussions will serve as a platform for discussing the clinical spectrum of cholelithiasis and its complications in children as well as discussing the latest evidence related to diagnosis and treatment.
January 20123'-Deoxy-3'-18F-Fluorothymidine PET and MRI for Early Survival Predictions in Patients with Recurrent Malignant Glioma Treated with Bevacizumab.
Schwarzenberg J, Czernin J, Cloughesy TF, Ellingson BM, Pope WB, Geist C, Dahlbom M, Silverman DH, Satyamurthy N, Phelps ME, Chen W.
With the dismal prognosis for malignant glioma patients, survival predictions become key elements in patient management. This study compares the value of 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) PET and MRI for early outcome predictions in patients with recurrent malignant glioma on bevacizumab therapy. Methods: Thirty patients treated with bevacizumab combination therapy underwent 18F-FLT PET immediately before and at 2 and 6 wk after the start of treatment. A metabolic treatment response was defined as a decrease of equal to or greater than 25% in tumor 18F-FLT uptake (standardized uptake values) from baseline using receiver-operating-characteristic analysis. MRI treatment response was assessed at 6 wk according to the Response Assessment in Neurooncology criteria. 18F-FLT responses at different times were compared with MRI response and correlated with progression-free survival and overall survival using Kaplan-Meier analysis. Metabolic response based on 18F-FLT was further compared with other outcome predictors using Cox regression analysis.
January 2012Treatment of High Risk Symptomatic Intracranial Atherosclerosis with Balloon Mounted Coronary Stents and Wingspan Stents: Single Center Experience Over a 10 Year Period.
Tarlov N, Jahan R, Saver JL, Sayre JW, Ali LK, Kim D, Duckwiler GR, Tateshima S, Viñuela F, Liebeskind DS.
Stenting of symptomatic intracranial atherosclerosis remains under investigation, yet this option to potentially avert subsequent stroke has been offered at select centers under humanitarian device exemption and off-label use for several years. Retrospective case series of consecutive patients undergoing stenting with Wingspan and balloon mounted coronary stents for symptomatic intracranial atherosclerosis at a single institution. Recurrent symptomatic ischemia in the territory of the stented artery was ascertained. Rates of recurrent ischemic stroke were calculated per patient-year of follow-up and were compared with medically treated patients in the WarfarinAspirin Symptomatic Intracranial Disease (WASID) trial.