February 2017Percutaneous Cryoablation for the Treatment of Recurrent Malignant Pleural Mesothelioma: Safety, Early-Term Efficacy, and Predictors of Local Recurrence.
Abtin F, Quirk MT, Suh RD, Hsu W, Han SX, Kim GJ, Genshaft S, Sandberg JK, Olevsky O, Cameron RB.
PURPOSE: To determine safety and early-term efficacy of CT-guided cryoablation for treatment of recurrent mesothelioma and assess risk factors for local recurrence. MATERIALS AND METHODS: During the period 2008-2012, 24 patients underwent 110 cryoablations for recurrent mesothelioma tumors in 89 sessions. Median patient age was 69 years (range, 48-82 y). Median tumor size was 30 mm (range, 9-113 mm). Complications were graded using Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v4.0). Recurrence was diagnosed on CT or positron emission tomography/CT by increasing size, nodular enhancement, or hypermetabolic activity and analyzed using the Kaplan-Meier method. Cox proportional hazards model was used to determine covariates associated with local tumor recurrence.
February 2017Light-sheet Fluorescence Imaging to Localize Cardiac Lineage and Protein Distribution.
Ding Y, Lee J, Ma J, Sung K, Yokota T, Singh N, Dooraghi M, Abiri P, Wang Y, Kulkarni RP, Nakano A, Nguyen TP, Fei P, Hsiai TK.
Light-sheet fluorescence microscopy (LSFM) serves to advance developmental research and regenerative medicine. Coupled with the paralleled advances in fluorescence-friendly tissue clearing technique, our cardiac LSFM enables dual-sided illumination to rapidly uncover the architecture of murine hearts over 10 by 10 by 10 mm3 in volume; thereby allowing for localizing progenitor differentiation to the cardiomyocyte lineage and AAV9-mediated expression of exogenous transmembrane potassium channels with high contrast and resolution. Without the steps of stitching image columns, pivoting the light-sheet and sectioning the heart mechanically, we establish a holistic strategy for 3-dimentional reconstruction of the "digital murine heart" to assess aberrant cardiac structures as well as the spatial distribution of the cardiac lineages in neonates and ion-channels in adults.
February 2017Prostate Artery Embolization for Benign Prostatic Hyperplasia: Current Status.
Mirakhur A, McWilliams JP.
Prostate artery embolization has garnered much attention as a promising treatment for lower urinary tract symptoms secondary to benign prostatic hyperplasia. We aim to provide an up-to-date review of this minimally invasive technique, including discussion of potential benefits and technical challenges. Current evidence suggests it is a safe and effective option for patients with medication-refractory urinary obstructive symptoms who are poor surgical candidates or refuse surgical therapy. Larger, randomized studies with long-term follow-up data are needed for this technique to be formally established in the treatment paradigm for benign prostatic hyperplasia.
February 2017Radiographic and Magnetic Resonance Imaging Identification of Thoracolumbar Spine Variants with Implications for the Positioning of the Conus Medullaris in Rhesus Macaques.
Ohlsson M, Nieto JH, Christe KL, Villablanca JP, Havton LA.
The anatomy of the vertebral column in mammals may differ between species and between subjects of the same species, especially with regards to the composition of the thoracolumbar spine. We investigated, using several noninvasive imaging techniques, the thoracolumbar spine of a total of 44 adult rhesus macaques of both genders. Radiographic examination of the vertebral column showed a predominant spine phenotype with 12 rib-bearing thoracic vertebrae and 7 lumbar vertebrae without ribs in 82% of subjects, whereas a subset of subjects demonstrated 13 rib-bearing thoracic vertebrae and 6 lumbar vertebrae without ribs. Computer tomography studies of the thoraco-lumbar spine in two cases with a pair of supernumerary ribs showed facet joints between the most caudal pair of ribs and the associated vertebra, supporting a thoracic phenotype. Magnetic resonance imaging (MRI) studies were used to determine the relationship between the lumbosacral spinal cord and the vertebral column. The length of the conus medullaris portion of the spinal cord was 1.5 ± 0.3 vertebral units, and its rostral and caudal positions in the spinal canal were at 2.0 ± 0.3 and 3.6 ± 0.4 vertebral units below the thoracolumbar junction, respectively (n = 44). The presence of a set of supernumerary ribs did not affect the length or craniocaudal position of the conus medullaris, and subjects with13 rib-bearing vertebrae may from a functional or spine surgical perspective be considered as exhibiting12 thoracic vertebrae and an L1 vertebra with ribs.
February 2017Bone Age and Mineral Density Assessments Using Plain Roentgenograms in Tenofovir-exposed Infants in Malawi and Brazil Enrolled in HIV Prevention Trials Network 057.
Osorio LE, Boechat MI, Mirochnick M, Kumwenda N, Kreitchmann R, Emel L, Pinto J, Joao E, Santos B, Swenson M, George K, Sato P, Mofenson L, Nielsen-Saines K; HIV Prevention Trials Network (HPTN) 057 Protocol Team..
BACKGROUND: Tenofovir disoproxil fumarate (TDF) use during pregnancy has been increasing, and studies linking bone toxicity with exposure to TDF have raised concern for its use in infants. METHODS: Hand/wrist and spine radiographs were obtained at 3 days and 12 weeks of age in infants born to HIV-infected pregnant women enrolled in the HIV Prevention Trials Network 057 pharmacokinetic study of TDF conducted in Malawi and Brazil assigned to 3 TDF dosing cohorts. In cohort 1, mothers received 600 mg of TDF during labor. In cohort 2, infants received 4 mg/kg dose on days 0, 3 and 5. In cohort 3, a 900 mg maternal dose was given during labor, followed by a 6 mg/kg infant dose on days 0, 3 and 5 of life.
February 2017Magnetic Resonance Imaging Underestimation of Prostate Cancer Geometry: Use of Patient Specific Molds to Correlate Images with Whole Mount Pathology.
Priester A, Natarajan S, Khoshnoodi P, Margolis DJ, Raman SS, Reiter RE, Huang J, Grundfest W, Marks LS.
PURPOSE: We evaluated the accuracy of magnetic resonance imaging in determining the size and shape of localized prostate cancer. MATERIALS AND METHODS: The subjects were 114 men who underwent multiparametric magnetic resonance imaging before radical prostatectomy with patient specific mold processing of the specimen from 2013 to 2015. T2-weighted images were used to contour the prostate capsule and cancer suspicious regions of interest. The contours were used to design and print 3-dimensional custom molds, which permitted alignment of excised prostates with magnetic resonance imaging scans. Tumors were reconstructed in 3 dimensions from digitized whole mount sections. Tumors were then matched with regions of interest and the relative geometries were compared.
February 2017A Bayesian Model for Estimating Multi-state Disease Progression.
Shen S, Han SX, Petousis P, Weiss RE, Meng F, Bui AA, Hsu W.
A growing number of individuals who are considered at high risk of cancer are now routinely undergoing population screening. However, noted harms such as radiation exposure, overdiagnosis, and overtreatment underscore the need for better temporal models that predict who should be screened and at what frequency. The mean sojourn time (MST), an average duration period when a tumor can be detected by imaging but with no observable clinical symptoms, is a critical variable for formulating screening policy. Estimation of MST has been long studied using continuous Markov model (CMM) with Maximum likelihood estimation (MLE). However, a lot of traditional methods assume no observation error of the imaging data, which is unlikely and can bias the estimation of the MST. In addition, the MLE may not be stably estimated when data is sparse. Addressing these shortcomings, we present a probabilistic modeling approach for periodic cancer screening data. We first model the cancer state transition using a three state CMM model, while simultaneously considering observation error. We then jointly estimate the MST and observation error within a Bayesian framework. We also consider the inclusion of covariates to estimate individualized rates of disease progression. Our approach is demonstrated on participants who underwent chest x-ray screening in the National Lung Screening Trial (NLST) and validated using posterior predictive p-values and Pearson's chi-square test. Our model demonstrates more accurate and sensible estimates of MST in comparison to MLE.
January 2017Baseline Pretreatment Contrast Enhancing Tumor Volume Including Central Necrosis is a Prognostic Factor in Recurrent Glioblastoma: Evidence from Single and Multicenter Trials.
Ellingson BM, Harris RJ, Woodworth DC, Leu K, Zaw O, Mason WP, Sahebjam S, Abrey LE, Aftab DT, Schwab GM, Hessel C, Lai A, Nghiemphu PL, Pope WB, Wen PY, Cloughesy TF.
BACKGROUND: The prognostic significance of baseline contrast enhancing tumor prior to second- or third-line therapy in recurrent glioblastoma (GBM) for overall survival (OS) remains controversial, particularly in the context of repeated surgical resection and/or use of anti-angiogenic therapy. In the current study, we examined recurrent GBM patients from both single and multicenter clinical trials to test whether baseline enhancing tumor volume, including central necrosis, is a significant prognostic factor for OS in recurrent GBM. METHODS: Included were 497 patients with recurrent GBM from 4 data sources: 2 single-center sites (University of Toronto, University of California Los Angeles) and 2 phase II multicenter trials (AVF3708G, Bevacizumab ± Irinotecan, NCT00345163; XL184-201, Cabozantinib, NCT00704288). T1 subtraction maps were used to define volume of contrast enhancing tumor, including central necrosis. Cox multivariable and univariate analyses were used to evaluate the relationship between tumor volume prior to second- or third-line therapy and OS.
January 2017Patient Size-Specific Analysis of Dose Indexes From CT Lung Cancer Screening.
Fujii K, McMillan K, Bostani M, Cagnon C, McNitt-Gray M.
OBJECTIVE: The U.S. Centers for Medicare & Medicaid Services (CMS) recently approved the use of low-dose CT for lung cancer screening and described volumetric CT dose index (CTDIvol) requirements. These were based on the National Lung Screening Trial, which used only fixed-tube-current techniques. The aim of this study was to evaluate dose index data from a lung cancer screening program using automatic exposure control (AEC) techniques to ensure compliance with requirements and to correlate dose index values with patient size. MATERIALS AND METHODS: CTDIvol, dose-length product (DLP), and body mass index (BMI) data were collected for 563 lung cancer screening examinations performed with AEC between January 1, 2014, through August 31, 2015. CTDIvol and DLP were analyzed according to the patient's BMI classification. Results were compared with the CMS requirement that the CTDIvol for a standard-sized patient (height, 170 cm; weight, 70 kg) be 3.0 mGy or less, with adjustments for patients of different sizes. For a subset of patients, the average water-equivalent diameter and size-specific dose estimate were estimated.
January 2017Percutaneous Lung Biopsy in the Molecular Profiling Era: A Survey of Current Practices.
Lee C, Guichet PL, Abtin F.
PURPOSE: This study aimed to assess the current practice patterns of radiologists performing percutaneous lung biopsies. MATERIALS AND METHODS: This cross-sectional study used a web-based survey sent to the Society of Thoracic Radiology membership from August to October 2015. Responses were collected anonymously, and results were tallied.
January 2017Multi-delay ASL Can Identify Leptomeningeal Collateral Perfusion in Endovascular Therapy of Ischemic Stroke.
Lou X, Yu S, Scalzo F, Starkman S, Ali LK, Kim D, Rao NM, Hinman JD, Vespa PM, Jahan R, Tateshima S, Gonzalez NR, Duckwiler GR, Saver JL, Yoo B, Salamon N, Lyu J, Ma L, Wang DJ, Liebeskind DS.
BACKGROUND AND PURPOSE: Multi-delay arterial spin-labeling (ASL) perfusion imaging has been used as a promising modality to evaluate cerebral perfusion. Our aim was to assess the association of leptomeningeal collateral perfusion scores based on ASL parameters with outcome of endovascular treatment in patients with acute ischemic stroke (AIS) in the middle cerebral artery (MCA) territory. MATERIALS AND METHODS: ASL data at 4 post-labeling delay (PLD) times (PLD = 1.5, 2, 2.5, 3 s) were acquired during routine clinical magnetic resonance examination on AIS patients prior to endovascular treatment. A 3-point scale of leptomeningeal collateral perfusion grade on 10 anatomic regions was determined based on arterial transit times (ATT), cerebral blood flow (CBF), and arterial cerebral blood volume (CBV), estimated by the multi-delay ASL protocol. Based on a 90-day modified Rankin Scale (mRS), the patients were dichotomized to moderate/good (mRS 0-3) and poor outcome (mRS 4-6) and the regional collateral flow scores were compared.
January 2017Utilization of Emergent Neuroimaging for Thrombolysis-Eligible Stroke Patients.
Sanossian N, Fu KA, Liebeskind DS, Starkman S, Hamilton S, Villablanca JP, Burgos AM, Conwit R, Saver JL.
BACKGROUND: Advances in diagnostic imaging of stroke include multimodal techniques such as noninvasive angiography and perfusion imaging. We aimed to characterize trends in neuroimaging utilization among acute stroke patients. Utilization of multimodal imaging for acute stroke in the community has remained largely uncharacterized despite its increased adoption at academic medical centers. METHODS: We quantified neuroimaging utilization in the emergency department (ED) for 1,700 hyperacute stroke patients presenting <2 hours after symptom onset who participated in the National Institutes of Health Field Administration of Stroke Therapy-Magnesium (FAST-MAG) study throughout Los Angeles and Orange Counties. FAST-MAG provided no recommendation as to imaging utilization.
January 2017Evaluating Small-Airways Disease in Asthmatic Patients: The Utility of Quantitative Computed Tomography.
Tashkin DP, Kim HJ, Zeidler M, Kleerup E, Goldin J.
The tracheobronchial tree comprises a branching system of airways, beginning with the trachea, in which each airway divides mostly dichotomously into 2 smaller airways of progressively smaller diameter and, in most cases, shorter length, down to the smallest airway (a respiratory bronchiole) before terminating after approximately 23 divisions in the distal air sacs and alveoli. Historically, the lower respiratory tract has been divided into large and small airways, the latter defined as airways of 2 mm in diameter or smaller and corresponding to approximately the seventh or eighth generation and beyond of branching airways. In view of the exponential increase in the number of airways with each successive generation, most of the tracheobronchial tree is comprised of small airways, the total cross-sectional area of which is much greater than that of the larger airways, resulting in a relatively low resistance to airflow in the healthy lung.
January 2017Clear Cell Renal Cell Carcinoma: Identifying the Gain of Chromosome 12 on Multiphasic MDCT.
Young JR, Coy H, Douek M, Lo P, Sayre J, Pantuck AJ, Raman SS.
PURPOSE: To determine whether multiphasic MDCT enhancement can help identify the gain of chromosome 12 in clear cell renal cell carcinomas (RCCs). METHODS: With IRB approval for this HIPAA-compliant case control study, we derived a cohort of 65 clear cell RCCs with preoperative four-phase renal mass MDCT from October 2000 to August 2013. Each lesion was segmented in its entirety on axial images in all phases. A computer-assisted detection (CAD) algorithm selected a 0.5-cm-diameter region of maximal attenuation within each lesion in each phase. Attenuation in each phase between clear cell RCCs with and without the gain of 12 was compared using t-tests.