April 2018Assessing the Effect of Lifetime Contralateral Breast Cancer Risk on the Selection of Contralateral Prophylactic Mastectomy for Unilateral Breast Cancer.
Hegde JV, Wang X, Attai DJ, DiNome ML, Kusske A, Hoyt AC, Hurvitz SA, Weidhaas JB, Steinberg ML, McCloskey SA.
INTRODUCTION: Contralateral prophylactic mastectomy (CPM) rates are rising, with fear implicated as a contributing factor. This study used a contralateral breast cancer (CBC) risk stratification tool to assess whether the selection of CPM is reflective of future CBC risk. PATIENTS AND METHODS: This retrospective study evaluated 404 women with unilateral breast cancer treated with breast conservation, unilateral mastectomy, or bilateral mastectomy within a single multidisciplinary clinic. Women were evaluated by the Manchester risk tool to calculate lifetime CBC risk. Logistic regression analysis was used to evaluate whether CBC risk was associated with CPM, and the clinical rationale for prophylactic mastectomy justification was recorded.
April 2018Spectral Resolution and High-flux Capability Tradeoffs in CdTe Detectors for Clinical CT.
Hsieh SS, Rajbhandary PL, Pelc NJ.
PURPOSE: Photon-counting detectors using CdTe or CZT substrates are promising candidates for future CT systems but suffer from a number of nonidealities, including charge sharing and pulse pileup. By increasing the pixel size of the detector, the system can improve charge sharing characteristics at the expense of increasing pileup. The purpose of this work is to describe these considerations in the optimization of the detector pixel pitch. METHODS: The transport of x rays through the CdTe substrate was simulated in a Monte Carlo fashion using GEANT4. Deposited energy was converted into charges distributed as a Gaussian function with size dependent on interaction depth to capture spreading from diffusion and Coulomb repulsion. The charges were then collected in a pixelated fashion. Pulse pileup was incorporated separately with Monte Carlo simulation. The Cramér-Rao lower bound (CRLB) of the measurement variance was numerically estimated for the basis material projections. Noise in these estimates was propagated into CT images. We simulated pixel pitches of 250, 350, and 450 microns and compared the results to a photon counting detector with pileup but otherwise ideal energy response and an ideal dual-energy system (80/140 kVp with tin filtration). The modeled CdTe thickness was 2 mm, the incident spectrum was 140 kVp and 500 mA, and the effective dead time was 67 ns. Charge summing circuitry was not modeled. We restricted our simulations to objects of uniform thickness and did not consider the potential advantage of smaller pixels at high spatial frequencies.
April 2018Understanding Brain Penetrance of Anticancer Drugs.
Levin VA, Ellingson BM.
This paper explicates the impact of tumor capillary permeability for glioma World Health Organization (WHO) grades II to IV on brain-penetrant drug entry and distribution within the tumor and the brain adjacent to tumor (leading edge). In addition, we consider the distribution of non-brain penetrant drugs and how, in some cases, large-molecular-weight drugs might achieve good distribution into tumor and brain adjacent to tumor.
April 2018Engineering a Clinically Translatable Bioartificial Pancreas to Treat Type I Diabetes.
Orive G, Emerich D, Khademhosseini A, Matsumoto S, Hernández RM, Pedraz JL, Desai T, Calafiore R, de Vos P.
Encapsulating, or immunoisolating, insulin-secreting cells within implantable, semipermeable membranes is an emerging treatment for type 1 diabetes. This approach can eliminate the need for immunosuppressive drug treatments to prevent transplant rejection and overcome the shortage of donor tissues by utilizing cells derived from allogeneic or xenogeneic sources. Encapsulation device designs are being optimized alongside the development of clinically viable, replenishable, insulin-producing stem cells, for the first time creating the possibility of widespread therapeutic use of this technology. Here, we highlight the status of the most advanced and widely explored implementations of cell encapsulation with an eye toward translating the potential of this technological approach to medical reality.
April 2018The Synergy of Scaffold-Based and Scaffold-Free Tissue Engineering Strategies.
Ovsianikov A, Khademhosseini A, Mironov V.
Tissue engineering (TE) is a highly interdisciplinary research field driven by the goal to restore, replace, or regenerate defective tissues. Throughout more than two decades of intense research, different technological approaches, which can be principally categorized into scaffold-based and scaffold-free strategies, have been developed. In this opinion article, we discuss the emergence of a third strategy in TE. This synergetic strategy integrates the advantages of both of these traditional approaches, while being clearly distinct from them. Its characteristic attributes, numerous practical benefits, and recent literature reports supporting our opinion, are discussed in detail.
April 2018Increased Affinity of Endothelial Cells to NiTi Using Ultraviolet Irradiation: An in Vitro Study.
Tateshima S, Kaneko N, Yamada M, Duckwiler G, Vinuela F, Ogawa T.
Nickel-titanium alloy (NiTi) is one of the most popular materials used endovascularly because of its shape memory and superelasticity. The NiTi device needs to be covered by endothelial cells after being placed in the blood vessel to reduce ischemic complications. The objective of this study was to examine the impact of ultraviolet (UV) irradiation on the biocompatibility of NiTi surfaces with endothelial cells. NiTi sheets were treated with UV irradiation for 48 h and human aorta derived endothelial cells were used in this study. UV irradiation converted the NiTi surface to hydrophilic state and increased albumin adsorption. The number of endothelial cell migration, attachment, proliferation as well as their metabolic activity were significantly increased on UV treated NiTi. This study provides the first evidence of the photoactivation of NiTi surfaces by UV irradiation and demonstrates improved biocompatibility of UV-treated NiTi surfaces with vascular endothelial cells. These results suggest that UV irradiation may promote endothelialization of NiTi devices in blood vessels.
April 2018An Expert Consensus for the Management of Chronic Hepatitis B in Asian Americans.
Tong MJ, Pan CQ, Han SB, Lu DS, Raman S, Hu KQ, Lim JK, Hann HW, Min AD.
BACKGROUND: Hepatitis B virus (HBV) infection is common with major clinical consequences. In Asian Americans, the HBsAg carrier rate ranges from 2% to 16% which approximates the rates from their countries of origin. Similarly, HBV is the most important cause of cirrhosis, hepatocellular carcinoma (HCC) and liver related deaths in HBsAg positive Asians worldwide. AIM: To generate recommendations for the management of Asian Americans infected with HBV. METHODS: These guidelines are based on relevant data derived from medical reports on HBV from Asian countries as well as from studies in the HBsAg positive Asian Americans. The guidelines herein differ from other recommendations in the treatment of both HBeAg positive and negative chronic hepatitis B (CHB), in the approach to HCC surveillance, and in the management of HBV in pregnant women.
April 2018Feasibility and Safety of Intrathoracic Biopsy and Repeat Biopsy for Evaluation of Programmed Cell Death Ligand-1 Expression for Immunotherapy in Non-Small Cell Lung Cancer.
Tsai EB, Pomykala K, Ruchalski K, Genshaft S, Abtin F, Gutierrez A, Kim HJ, Li A, Adame C, Jalalian A, Wolf B, Garon EB, Goldman JW, Suh R.
Purpose To determine feasibility and safety of biopsy and repeat biopsy for assessment of programmed cell death ligand-1 (PD-L1) status. Materials and Methods This retrospective analysis reviewed 101 patients who underwent transthoracic core needle biopsy for the KEYNOTE-001 (MK-3475) clinical trial of pembrolizumab, an antiprogrammed cell death-1 therapy for non-small cell lung cancer, from May 2012 to September 2014. Sixty-one male patients (mean age, 66.1 years; range 36-83 years) and 40 female patients (mean age, 66.8 years; age range, 36-90 years) were included. Data collected included population characteristics, treatment history, target location, size, and depth from pleura. Adequacy of the tissue sample for diagnostic testing and rates of biopsy-related complications were assessed. Statistical analysis was performed by using univariate and multivariate generalized linear models to determine significant risk factors for biopsy complications. Results A total of 110 intrathoracic biopsies were performed, and 101 (91.8%) were performed as repeat biopsies subsequent to a previous percutaneous or bronchoscopic biopsy or previous surgical biopsy or resection. More than 84.5% (93 of 110) of biopsies were performed in patients who had undergone previous local or systemic therapy. Specimens were adequate for evaluation of PD-L1 expression in 96.4% of biopsies. Procedure-related complications occurred in 28 biopsies (25.4%); pneumothorax was most common (22.7%). Overall mean number of core needle biopsy samples obtained was 7.9 samples. Conclusion Image-guided transthoracic core needle biopsy is an effective method for obtaining tissue for PD-L1 expression analysis.
March 2018Semi-automated Pulmonary Nodule Interval Segmentation Using the NLST Data.
Balagurunathan Y, Beers A, Kalpathy-Cramer J, McNitt-Gray M, Hadjiiski L, Zhao B, Zhu J, Yang H, Yip SSF, Aerts HJWL, Napel S, Cherezov D, Cha K, Chan HP, Flores C, Garcia A, Gillies R, Goldgof D.
PURPOSE: To study the variability in volume change estimates of pulmonary nodules due to segmentation approaches used across several algorithms and to evaluate these effects on the ability to predict nodule malignancy. METHODS: We obtained 100 patient image datasets from the National Lung Screening Trial (NLST) that had a nodule detected on each of two consecutive low dose computed tomography (LDCT) scans, with an equal proportion of malignant and benign cases (50 malignant, 50 benign). Information about the nodule location for the cases was provided by a screen capture with a bounding box and its axial location was indicated. Five participating quantitative imaging network (QIN) institutions performed nodule segmentation using their preferred semi-automated algorithms with no manual correction; teams were allowed to provide additional manually corrected segmentations (analyzed separately). The teams were asked to provide segmentation masks for each nodule at both time points. From these masks, the volume was estimated for the nodule at each time point; the change in volume (absolute and percent change) across time points was estimated as well. We used the concordance correlation coefficient (CCC) to compare the similarity of computed nodule volumes (absolute and percent change) across algorithms. We used Logistic regression model on the change in volume (absolute change and percent change) of the nodules to predict the malignancy status, the area under the receiver operating characteristic curve (AUROC) and confidence intervals were reported. Because the size of nodules was expected to have a substantial effect on segmentation variability, analysis of change in volumes was stratified by lesion size, where lesions were grouped into those with a longest diameter of <8 mm and those with longest diameter ≥ 8 mm.
March 2018Synergistic Interplay Between the Two Major Bone Minerals, Hydroxyapatite and Whitlockite Nanoparticles, for Osteogenic Differentiation of Mesenchymal Stem Cells.
Cheng H, Chabok R, Guan X, Chawla A, Li Y, Khademhosseini A, Jang HL.
The inorganic part of human bone is mainly composed of hydroxyapatite (HAP: Ca10(PO4)6(OH)2) and whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12) minerals, where the WH phase occupies up to 20-35% of total weight. These two bone minerals have different crystal structures and physicochemical properties, implying their distinguished role in bone physiology. However, until now, the biological significance of the presence of a certain ratio between HAP and WH in bone is unclear. To address this fundamental question, bone mimetic scaffolds are designed to encapsulate human mesenchymal stem cells (MSCs) for assessing their osteogenic activity depending on different ratios of HAP and WH. Interestingly, cellular growth and osteogenic differentiation are significantly promoted when MSCs are grown with a 3-1 ratio of HAP and WH nanoparticles, which is similar to bone. One of the reasons for this synergism between HAP and WH in hydrogel scaffolds is that, while WH nanoparticles can enhance osteogenic differentiation of MSCs compared to HAP, WH counterintuitively decreases the mechanical stiffness of nanocomposite hydrogels and hinders the osteogenic activity of cells. Taken together, these findings identify the optimal ratio between two major minerals in bone mimetic scaffolds to maximize the osteogenic differentiation of MSCs.
March 2018Evidence and Context of Use for Contrast Enhancement as a Surrogate of Disease Burden and Treatment Response in Malignant Glioma.
Ellingson BM, Wen PY, Cloughesy TF.
The use of contrast enhancement within the brain on CT or MRI has been the gold standard for diagnosis and therapeutic response assessment in malignant gliomas for decades. The use of contrast enhancing tumor size, however, remains controversial as a tool for accurately diagnosing and assessing treatment efficacy in malignant gliomas, particularly in the current, quickly evolving therapeutic landscape. The current article consolidates overwhelming evidence from hundreds of studies in the field of neuro-oncology, providing the necessary evidence base and specific contexts of use for consideration of contrast enhancing tumor size as an appropriate surrogate biomarker for disease burden and as a tool for measuring treatment response in malignant glioma, including glioblastoma.
March 2018Radiologic Progression of Glioblastoma Under Therapy-an Exploratory Analysis of AVAglio.
Nowosielski M, Ellingson BM, Chinot OL, Garcia J, Revil C, Radbruch A, Nishikawa R, Mason WP, Henriksson R, Saran F, Kickingereder P, Platten M, Sandmann T, Abrey LE, Cloughesy TF, Bendszus M, Wick W.
BACKGROUND: In this exploratory analysis of AVAglio, a randomized phase III clinical study that investigated the addition of bevacizumab (Bev) to radiotherapy/temozolomide in newly diagnosed glioblastoma, we aim to radiologically characterize glioblastoma on therapy until progression and investigate whether the type of radiologic progression differs between treatment arms and is related to survival and molecular data. METHODS: Five progression types (PTs) were categorized using an adapted algorithm according to MRI contrast enhancement behavior in T1- and T2-weighted images in 621 patients (Bev, n = 299; placebo, n = 322). Frequencies of PTs (designated as classic T1, cT1 relapse, T2 diffuse, T2 circumscribed, and primary nonresponder), time to progression (PFS), and overall survival (OS) were assessed within each treatment arm and compared with molecular subtypes and O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status.
March 2018Electrically Driven Microengineered Bioinspired Soft Robots.
Shin SR, Migliori B, Miccoli B, Li YC, Mostafalu P, Seo J, Mandla S, Enrico A, Antona S, Sabarish R, Zheng T, Pirrami L, Zhang K, Zhang YS, Wan KT, Demarchi D, Dokmeci MR, Khademhosseini A.
To create life-like movements, living muscle actuator technologies have borrowed inspiration from biomimetic concepts in developing bioinspired robots. Here, the development of a bioinspired soft robotics system, with integrated self-actuating cardiac muscles on a hierarchically structured scaffold with flexible gold microelectrodes is reported. Inspired by the movement of living organisms, a batoid-fish-shaped substrate is designed and reported, which is composed of two micropatterned hydrogel layers. The first layer is a poly(ethylene glycol) hydrogel substrate, which provides a mechanically stable structure for the robot, followed by a layer of gelatin methacryloyl embedded with carbon nanotubes, which serves as a cell culture substrate, to create the actuation component for the soft body robot. In addition, flexible Au microelectrodes are embedded into the biomimetic scaffold, which not only enhance the mechanical integrity of the device, but also increase its electrical conductivity. After culturing and maturation of cardiomyocytes on the biomimetic scaffold, they show excellent myofiber organization and provide self-actuating motions aligned with the direction of the contractile force of the cells. The Au microelectrodes placed below the cell layer further provide localized electrical stimulation and control of the beating behavior of the bioinspired soft robot.
March 2018Gadolinium Deposition in the Paediatric Brain: T1-weighted Hyperintensity within the Dentate Nucleus Following Repeated Gadolinium-based Contrast Agent Administration.
Young JR, Orosz I, Franke MA, Kim HJ, Woodworth D, Ellingson BM, Salamon N, Pope WB.
AIM: To determine whether repeated gadolinium-based contrast agent administration (GBCA) in children is associated with the development of increased T1-weighted signal intensity within the cerebellar dentate nucleus. MATERIALS AND METHODS: With institutional review board approval for this The Health Insurance Portability and Accountability Act-compliant retrospective study, a cohort of 41 patients under the age of 18 years who underwent at least four contrast-enhanced magnetic resonance imaging (MR) examinations of the brain from 2005 to 2015 were identified. For each examination, both dentate nuclei were manually contoured, and the mean dentate nucleus-to-pons signal intensity (DN-P SI) ratio was calculated. The DN-P SI ratios from the last to first MRI examination were compared, and the correlation between DN-P SI ratio and cumulative gadolinium dose was calculated using a linear mixed effect model to control for potentially confounding variables.
March 2018ASPECTS-based Reperfusion Status on Arterial Spin Labeling is Associated with Clinical Outcome in Acute Ischemic Stroke Patients.
Yu S, Ma SJ, Liebeskind DS, Yu D, Li N, Qiao XJ, Shao X, Yan L, Yoo B, Scalzo F, Hinman JD, Sharma LK, Rao N, Jahan R, Tateshima S, Duckwiler GR, Saver JL, Salamon N, Wang DJ.
The purpose of this study was to develop and evaluate a scoring system for assessing reperfusion status based on arterial spin labeled (ASL) perfusion MRI in acute ischemic stroke (AIS) patients receiving thrombolysis and/or endovascular treatment. Pseudo-continuous ASL with background suppressed 3D GRASE was acquired along with DWI in 90 patients within 24 h post-treatment. An automatic reperfusion scoring system (auto-RPS) was devised based on the Alberta Stroke Program Early CT Score (ASPECTS) template, and compared with manual RPS and DWI-ASPECTS. TICI (thrombolysis in cerebral infarction) scores were graded in 48 patients who received endovascular treatment. Favorable outcomes were defined by a modified Rankin Scale score of 0-2 at three months. Auto-RPS was positively correlated with DWI-ASPECTS (ρ = 0.6, P < 0.001) and was on average 1 point lower than DWI-ASPECTS ( P < 0.001). The area under the receiver operating characteristic curve for discriminating poor functional outcome (n = 90) was 0.75 (95% CI, 0.64-0.86) for manual RPS, 0.85 (95% CI, 0.76-0.94) for auto-RPS, and 0.81 (95% CI, 0.71-0.90) for DWI-ASPECTS. Multiple logistic regression analysis in the TICI-graded patients (n = 48) showed that auto-RPS is highly associated with functional outcome (OR = 25.2, 95% CI 4.02-496, P < 0.01). Post treatment auto-RPS within 24 h provides a useful tool to predict functional outcome in AIS patients.
February 2018Cardiac Magnetic Resonance Imaging Using Wideband Sequences in Patients with Nonconditional Cardiac Implanted Electronic Devices.
Do DH, Eyvazian V, Bayoneta AJ, Hu P, Finn JP, Bradfield JS, Shivkumar K, Boyle NG.
BACKGROUND: Magnetic resonance imaging (MRI) has been performed safely in patients without MRI-conditional cardiac implantable electronic devices (CIEDs), but experience specifically with cardiac magnetic resonance imaging (CMR) is limited in this patient population. OBJECTIVE: Evaluate the safety of CMR in non-MRI-conditional CIEDs and the interpretability of images using wideband sequences. METHODS: We performed 114 consecutive CMR studies in 111 patients (mean age 59 ± 14 years, with 12 pacemakers, 73 implantable cardioverter defibrillators, 29 biventricular defibrillators) using a wideband pulse sequence for late gadolinium enhancement (LGE) imaging. A standardized protocol for device management and patient monitoring was followed. Patients were evaluated for major clinical adverse events and device parameter changes immediately after CMR and at clinical follow-up.
February 2018Diagnostic Criteria for Idiopathic Pulmonary Fibrosis: a Fleischner Society White Paper.
Lynch DA, Sverzellati N, Travis WD, Brown KK, Colby TV, Galvin JR, Goldin JG, Hansell DM, Inoue Y, Johkoh T, Nicholson AG, Knight SL, Raoof S, Richeldi L, Ryerson CJ, Ryu JH, Wells AU.
This Review provides an updated approach to the diagnosis of idiopathic pulmonary fibrosis (IPF), based on a systematic search of the medical literature and the expert opinion of members of the Fleischner Society. A checklist is provided for the clinical evaluation of patients with suspected usual interstitial pneumonia (UIP). The role of CT is expanded to permit diagnosis of IPF without surgical lung biopsy in select cases when CT shows a probable UIP pattern. Additional investigations, including surgical lung biopsy, should be considered in patients with either clinical or CT findings that are indeterminate for IPF. A multidisciplinary approach is particularly important when deciding to perform additional diagnostic assessments, integrating biopsy results with clinical and CT features, and establishing a working diagnosis of IPF if lung tissue is not available. A working diagnosis of IPF should be reviewed at regular intervals since the diagnosis might change. Criteria are presented to establish confident and working diagnoses of IPF.
February 2018A Structured Global Health Training Program for Radiology Residents.
Pool KL, Culp MP, Mollura DJ, Suh R.
The World Health Organization (WHO) increasingly recognizes the need and utility for quality diagnostic tests. Historically, imaging has played a key role for diagnosis and treatment plans for global health infectious diseases, like tuberculosis and human immunovirus (HIV) and acquired immunodeficiency syndrome. However, according to the WHO, there is a global rise in noncommunicable diseases, such as cancer and cardiovascular diseases, for which imaging has been an integral part of care in areas of high access to health care for decades . In analysis of WHO member states, a wide gap is shown between nations that have imaging and related treatment services and those that have minimal to no access . This background supports the increasing trend for radiology to be part of global health initiatives and underscores the dire need for medical imaging services in areas that currently lack access and human capacity ...
February 2018Investigating the Minimum Scan Parameters Required to Generate Free-breathing Motion Artefact-free Fast-helical CT.
Thomas DH, Tan J, Neylon J, Dou T, O'Connell D, McNitt-Gray M, Lee P, Lamb J, Low DA.
OBJECTIVE: A recently proposed "5DCT" protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artefacts, which arise when tissue motion is greater than scan speed. METHODS: Using a unique set of digital phantoms based on patient data and verified with a motion phantom, this work identifies the minimum scanner parameters required to successfully generate free-breathing artefact-free fast-helical scans. A motion phantom and 5 patients were imaged 25 times under free-breathing conditions in alternating directions with a 64-slice CT scanner employing a low-dose fast-helical protocol. A series of high temporal resolution (0.1 s) 5DCT scan data sets was generated in each case. A simulated CT scanner was used to "image" each free-breathing data set. Various CT scanner detector widths and rotation times were simulated, and verified using the motion phantom results. Motion-induced artefacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices.
January 2018Quantitative Bone Scan Lesion Area as an Early Surrogate Outcome Measure Indicative of Overall Survival in Metastatic Prostate Cancer.
Brown MS, Kim GHJ, Chu GH, Ramakrishna B, Allen-Auerbach M, Fischer CP, Levine B, Gupta PK, Schiepers CW, Goldin JG.
A clinical validation of the bone scan lesion area (BSLA) as a quantitative imaging biomarker was performed in metastatic castration-resistant prostate cancer (mCRPC). BSLA was computed from whole-body bone scintigraphy at baseline and week 12 posttreatment in a cohort of 198 mCRPC subjects (127 treated and 71 placebo) from a clinical trial involving a different drug from the initial biomarker development. BSLA computation involved automated image normalization, lesion segmentation, and summation of the total area of segmented lesions on bone scan AP and PA views as a measure of tumor burden. As a predictive biomarker, treated subjects with baseline BSLA [Formula: see text] had longer survival than those with higher BSLA ([Formula: see text] and [Formula: see text]). As a surrogate outcome biomarker, subjects were categorized as progressive disease (PD) if the BSLA increased by a prespecified 30% or more from baseline to week 12 and non-PD otherwise. Overall survival rates between PD and non-PD groups were statistically different ([Formula: see text] and [Formula: see text]). Subjects without PD at week 12 had longer survival than subjects with PD: median 398 days versus 280 days. BSLA has now been demonstrated to be an early surrogate outcome for overall survival in different prostate cancer drug treatments.
January 2018Improved Spatiotemporal Resolution of Dynamic Susceptibility Contrast Perfusion MRI in Brain Tumors Using Simultaneous Multi-Slice Echo-Planar Imaging.
Chakhoyan A, Leu K, Pope WB, Cloughesy TF, Ellingson BM.
DSC perfusion MR imaging in brain tumors requires a trade-off between spatial and temporal resolution, resulting in less spatial coverage to meet the temporal resolution requirements for accurate relative CBV estimation. DSC-MR imaging could potentially benefit from the advantages associated with simultaneous multi-slice imaging, including increased spatiotemporal resolution. In the current article, we demonstrate how simultaneous multi-slice EPI can be used to improve DSC-MR imaging spatiotemporal resolution in patients with glioblastoma.
January 2018Evaluating Casama: Contextualized Semantic Maps for Summarization of Lung Cancer Studies.
Garcia-Gathright JI, Matiasz NJ, Adame C, Sarma KV, Sauer L, Smedley NF, Spiegel ML, Strunck J, Garon EB, Taira RK, Aberle DR, Bui AAT.
OBJECTIVE: It is crucial for clinicians to stay up to date on current literature in order to apply recent evidence to clinical decision making. Automatic summarization systems can help clinicians quickly view an aggregated summary of literature on a topic. Casama, a representation and summarization system based on "contextualized semantic maps," captures the findings of biomedical studies as well as the contexts associated with patient population and study design. This paper presents a user-oriented evaluation of Casama in comparison to a context-free representation, SemRep. MATERIALS AND METHODS: The effectiveness of the representation was evaluated by presenting users with manually annotated Casama and SemRep summaries of ten articles on driver mutations in cancer. Automatic annotations were evaluated on a collection of articles on EGFR mutation in lung cancer. Seven users completed a questionnaire rating the summarization quality for various topics and applications.
January 2018Nature's Wastebasket: The Role of the External Carotid Artery in Acute Stroke.
Jones J, Liang CW, Ramezan-Arab N, Duckwiler G, Tateshima S.
We describe a novel technical approach to acute stroke illustrated by the case of a 41 year old male who presented with tandem right common carotid artery (CCA) and M1 occlusions. His NIHSS was 17 and Alberta stroke programe early CT score (ASPECTs) was 8. Thrombectomy initially proved challenging due to large volume CCA thrombus that repeatedly occluded the aspiration catheters. However, by inflating a balloon distally and pulling clot into the adjacent ECA, we were able to quickly restore distal contrast flow to the intracranial circulation and achieve Thrombolysis In Cerebral Infarction/Arterial Occlusive Lesion (TICI2C/AOL3) revascularization.
January 2018Low-dose CT Perfusion with Projection View Sharing.
Martin T, Hoffman J, Alger JR, McNitt-Gray M, Wang DJ.
PURPOSE: CT Perfusion (CTP) is a widely used clinical imaging modality. However, CTP typically involves the use of substantial radiation dose (CTDIvol ≥~200 mGy). The purpose of this study is to present a low-dose CTP technique using a projection view-sharing reconstruction algorithm originally developed for dynamic MRI - "K-space Weighted Image Contrast" (KWIC). METHODS: The KWIC reconstruction is based on an angle-bisection scheme. In KWIC, a Fourier transform was performed along each projection to form a "k-space"-like CT data space, based on the central-slice theorem. As a projection view-sharing technique, KWIC preserves the spatiotemporal resolution of undersampled CTP data by progressively increasing the number of projection views shared for more distant regions of "k-space". KWIC reconstruction was evaluated on a digital FORBILD head phantom with numerically simulated time-varying objects. The numerically simulated scans were undersampled using the angle-bisection scheme to achieve 50%, 25%, and 12.5% of the original dose (288, 144, and 72 projections, respectively). The area-under-the-curve (AUC), time-to-peak (TTP), and full width half maximum (FWHM) were measured in KWIC recons and compared to fully sampled filtered back projection (FBP) reconstructions. KWIC reconstruction and dose reduction was also implemented for three clinical CTP cases (45 s, 1156 projections per turn, 1 s/turn, CTDIvol 217 mGy). Quantitative perfusion metrics were computed and compared between KWIC reconstructed CTP data and those of standard FBP reconstruction.
January 2018High Resolution Three-Dimensional Delayed Contrast MRI Detects Endolymphatic Hydrops in Patients With Vertigo and Vestibular Schwannoma.
Moayer R, Ishiyama GP, Karnezis S, Sepahdari AR, Ishiyama A.
OBJECTIVE: Advances in high resolution magnetic resonance imaging (MRI) have enabled the detection of endolymphatic hydrops (EH), a pathological ballooning of the endolymphatic fluid system, known to be associated with Menière's disease. When a patient has a known diagnosis of vestibular schwannoma and develops recurrent episodic vertigo spells, many surgeons recommend surgical intervention, attributing the vestibular symptoms to the vestibular schwannoma. The aim of this study is to evaluate the clinical outcome in patients with vestibular schwannoma and EH, treated medically, for recurrent spells of vertigo. PATIENTS: Two patients with EH and vestibular schwannoma who presented with recurrent spells of vertigo are included. Both had characteristic low frequency hearing loss ipsilateral to the schwannoma. INTERVENTION: MRI sequences with 3T scanner (Skyra, Siemens Healthcare, Erlangen, Germany) using high resolution three-dimensional delayed postcontrast protocol included "cisternographic" T2 and delayed intravenous-enhanced three-dimensional fluid-attenuation inversion recovery (DIVE-3D-FLAIR) sequences, performed with 2350ms (bright perilymph) and 2050ms (bright endolymph) inversion times and with subtracted images.
January 2018Ferumoxytol-enhanced MR Angiography for Vascular Access Mapping before Transcatheter Aortic Valve Replacement in Patients with Renal Impairment: A Step Toward Patient-specific Care.
Nguyen KL, Moriarty JM, Plotnik AN, Aksoy O, Yoshida T, Shemin RJ, Suh WM, Finn JP.
PURPOSE: To assess the technical feasibility of the use of ferumoxytol-enhanced (FE) magnetic resonance (MR) angiography for vascular mapping before transcatheter aortic valve replacement in patients with renal impairment. MATERIALS AND METHODS: This was an institutional review board-approved and HIPAA-compliant study. FE MR angiography was performed at 3.0 T or 1.5 T. Unenhanced computed tomographic (CT) images were used to overlay vascular calcification on FE MR angiographic images as composite fused three-dimensional data. Image quality of the subclavian and aortoiliofemoral arterial tree and confidence in the assessment of calcification were evaluated by using a four-point scale (4 = excellent vascular definition or strong confidence). Signal intensity nonuniformity as reflected by the heterogeneity index (ratio between the mean standard deviation of luminal signal intensity and the mean luminal signal intensity), signal-to-noise ratio, and consistency of luminal diameter measurements were quantified. Findings at FE MR angiography were compared with pelvic angiograms.
January 2018Brain Metastases: Neuroimaging.
Magnetic resonance imaging (MRI) is the cornerstone for evaluating patients with brain masses such as primary and metastatic tumors. Important challenges in effectively detecting and diagnosing brain metastases and in accurately characterizing their subsequent response to treatment remain. These difficulties include discriminating metastases from potential mimics such as primary brain tumors and infection, detecting small metastases, and differentiating treatment response from tumor recurrence and progression. Optimal patient management could be benefited by improved and well-validated prognostic and predictive imaging markers, as well as early response markers to identify successful treatment prior to changes in tumor size. To address these fundamental needs, newer MRI techniques including diffusion and perfusion imaging, MR spectroscopy, and positron emission tomography (PET) tracers beyond traditionally used 18-fluorodeoxyglucose are the subject of extensive ongoing investigations, with several promising avenues of added value already identified. These newer techniques provide a wealth of physiologic and metabolic information that may supplement standard MR evaluation, by providing the ability to monitor and characterize cellularity, angiogenesis, perfusion, pH, hypoxia, metabolite concentrations, and other critical features of malignancy. This chapter reviews standard and advanced imaging of brain metastases provided by computed tomography, MRI, and amino acid PET, focusing on potential biomarkers that can serve as problem-solving tools in the clinical management of patients with brain metastases.
January 2018Myeloablative Autologous Stem-Cell Transplantation for Severe Scleroderma.
Sullivan KM, Goldmuntz EA, Keyes-Elstein L, McSweeney PA, Pinckney A, Welch B, Mayes MD, Nash RA, Crofford LJ, Eggleston B, Castina S, Griffith LM, Goldstein JS, Wallace D, Craciunescu O, Khanna D, Folz RJ, Goldin J, St Clair EW, Seibold JR, Phillips K, Mineishi S, Simms RW, Ballen K, Wener MH, Georges GE, Heimfeld S, Hosing C, Forman S, Kafaja S, Silver RM, Griffing L, Storek J, LeClercq S, Brasington R, Csuka ME, Bredeson C, Keever-Taylor C, Domsic RT, Kahaleh MB, Medsger T, Furst DE; SCOT Study Investigators.
BACKGROUND: Despite current therapies, diffuse cutaneous systemic sclerosis (scleroderma) often has a devastating outcome. We compared myeloablative CD34+ selected autologous hematopoietic stem-cell transplantation with immunosuppression by means of 12 monthly infusions of cyclophosphamide in patients with scleroderma. METHODS: We randomly assigned adults (18 to 69 years of age) with severe scleroderma to undergo myeloablative autologous stem-cell transplantation (36 participants) or to receive cyclophosphamide (39 participants). The primary end point was a global rank composite score comparing participants with each other on the basis of a hierarchy of disease features assessed at 54 months: death, event-free survival (survival without respiratory, renal, or cardiac failure), forced vital capacity, the score on the Disability Index of the Health Assessment Questionnaire, and the modified Rodnan skin score.
January 2018Visual Aids for Patient, Family, and Physician Decision Making About Endovascular Thrombectomy for Acute Ischemic Stroke.
Tokunboh I, Vales Montero M, Zopelaro Almeida MF, Sharma L, Starkman S, Szeder V, Jahan R, Liebeskind D, Gonzalez N, Demchuk A, Froehler MT, Goyal M, Lansberg MG, Lutsep H, Schwamm L, Saver JL.
BACKGROUND AND PURPOSE: Rapid decision making optimizes outcomes from endovascular thrombectomy for acute cerebral ischemia. Visual displays facilitate swift review of potential outcomes and can accelerate decision processes. METHODS: From patient-level, pooled randomized trial data, 100 person-icon arrays (Kuiper-Marshall personographs) were generated showing beneficial and adverse effects of endovascular thrombectomy for patients with acute cerebral ischemia and large vessel occlusion using (1) automated (algorithmic) and (2) expert-guided joint outcome table specification.
January 2018Lung Cancer Radiogenomics: The Increasing Value of Imaging in Personalized Management of Lung Cancer Patients.
Vardhanabhuti V, Kuo MD.
Radiogenomics provide a large-scale data analytical framework that aims to understand the broad multiscale relationships between the complex information encoded in medical images (including computational, quantitative, and semantic image features) and their underlying clinical, therapeutic, and biological associations. As such it is a powerful and increasingly important tool for both clinicians and researchers involved in the imaging, evaluation, understanding, and management of lung cancers. Herein we provide an overview of the growing field of lung cancer radiogenomics and its applications.