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Stereotactic body radiation therapy (SBRT) is an emerging locoregional treatment (LRT) modality used in the management of patients with hepatocellular carcinoma (HCC). The decision to treat HCC with LRT is evaluated in a multidisciplinary setting, and the specific LRT chosen depends on the treatment intent, such as bridge-to-transplant, down-staging to transplant, definitive/curative treatment, and/or palliation, as well as underlying patient clinical factors. Accurate assessment of treatment response is necessary in order to guide clinical management in these patients. Patients who undergo LRT need continuous imaging evaluation to assess treatment response and to evaluate for recurrence. Thus, an accurate understanding of expected post-SBRT imaging findings is critical to avoid misinterpreting normal post-treatment changes as local progression or viable tumor. SBRT-treated HCC demonstrates unique imaging findings that differ from HCC treated with other forms of LRT. In particular, SBRT-treated HCC can demonstrate persistent APHE and washout on short-term follow-up imaging. This brief review summarizes current evidence for the use of SBRT for HCC, including patient population, SBRT technique and procedure, tumor response assessment on contrast-enhanced cross-sectional imaging with expected findings, and pitfalls in treatment response evaluation.

Simultaneous pancreas-kidney transplant remains a treatment option for patients with insulin-dependent diabetes mellitus type 1, aimed at restoring normoglycemia, alleviating insulin dependency, avoiding diabetic nephropathy, and thereby improving the quality of life. Imaging remains critical in the assessment of these transplant grafts. Ultrasound with Doppler remains the primary imaging modality for establishing baseline assessment of the graft as well as for evaluating vascular, parenchymal, and perigraft complications. Noncontrast MR imaging is preferred over non-contrast CT for evaluation of parenchymal or perigraft complications in patients with decreased renal function, although contrast-enhanced CT/MR imaging may be obtained following multidisciplinary consultation in cases with high clinical and laboratory suspicion for graft dysfunction. Catheter angiography is reserved primarily for therapeutic intervention in suspected or confirmed vascular complications. An understanding of the surgical techniques and imaging appearance of a normal graft is crucial to identify potential complications and direct timely management. This article provides an overview of surgical techniques, normal imaging appearance, as well as the spectrum of imaging findings and potential complications in pancreas-kidney transplants.

The purpose of this study is to review the recent literature analyzing the performance of Liver Imaging Reporting and Data System (LI-RADS) v2018 diagnostic and treatment response algorithm (TRA) for initial diagnosis and assessment of hepatocellular carcinoma (HCC) following locoregional therapy (LRT). LI-RADS is a comprehensive tool for assessment and reporting of observations in patients at risk of developing HCC. Since HCC is predominantly an imaging diagnosis, it is important to achieve a high sensitivity and specificity for each LR category. Therefore, a multitude of studies have been published over the recent years illustrating the diagnostic yield of both the diagnostic and treatment response algorithms. In addition, the role of abbreviated MRI for screening has also been studied recently. LI-RADS diagnostic algorithm has been validated by a number of recent studies that have provided a high diagnostic reliability for categorizing each observation, when using major as well as combination of major and ancillary features. In addition, LI-RADS TRA is being validated by the emerging literature providing promising results for treatment of HCC following ablation and nonradiation-based arterial therapies. However, further insight and in depth research is required to validate the imaging appearance of radiation-based therapies as well as utilization of ancillary features for response assessment after locoregional therapy.

To determine the long-term natural history of size change in SBRT-treated HCC to identify an imaging biomarker to help assess treatment response. This was a retrospective cohort study of consecutive HCCs treated with SBRT from January 2008 to December 2016 with either 2 years post-treatment MRI follow-up or post-treatment resection histology. Size, major features for HCC, and mRECIST and LI-RADS v.2018 treatment response criteria were assessed at each post-treatment MRI. Local progression, distant progression, and survival were modeled with Kaplan Meier analyses. 56 HCCs met inclusion criteria. Mean baseline HCC diameter was 30 mm (range: 9–105 mm). At 3 months, 76% (N = 43) of treated HCCs decreased in size (mean reduction: 8 mm, range: 5–99 mm) and 0% (N = 0) increased in size. By 24 months, 11% (N = 5) had increased in size and were considered local progression. APHE remained in 77% (43/56) at 3 months, 38% (19/50) at 12 months, and 23% (11/47) at 24 months. mRECIST-defined viable disease was observed in 77% (43/56) at 3 months and 20% (9/47) at 24 months. LI-RADS v.2018 criteria identified viable or equivocal disease in 0% at 3 months and 10% (5/47) at 24 months. Gradual loss of APHE and slow decrease in size are normal findings in HCCs treated with SBRT, and persistent APHE does not indicate viable disease. mRECIST is not accurate in the assessment of HCC after SBRT due to an overreliance on APHE to define viable disease. Increasing mass size or new nodular APHE at the treatment site may indicate local progression.

Spontaneous coronary artery dissection (SCAD) is a nonatherosclerotic cause of myocardial infarction in young and middle-aged women that has gained increasing awareness in recent years. Its diagnosis presents a challenge. Invasive coronary angiography is the primary imaging modality for diagnosing SCAD; however, it carries risk in these patients, who have an increased predisposition to complications. Advances in CT technology enable robust noninvasive evaluation of the coronary arteries at low radiation doses and have been increasingly utilized for the diagnosis or resolution of SCAD, in hemodynamically stable patients or when diagnosis of SCAD is uncertain at invasive angiography, particularly in proximal vessels. However, criteria for the diagnosis of SCAD with use of coronary CT angiography (CCTA) have not been currently established, and sensitivity and specificity for diagnosis have not yet been defined. The appearance of SCAD at CCTA can be subtle and can be missed, especially in distal small-caliber coronary arteries; hence utilization of other noninvasive imaging multimodalities may help solve this diagnostic challenge. Accurate and prompt diagnosis is vital, as management of SCAD differs significantly from that of traditional atherosclerotic acute coronary syndromes, with conservative management preferred for the majority of SCAD patients, and invasive treatment reserved for those with ongoing or recurrent ischemia, heart failure, or hemodynamic compromise. The goal of this review is twofold

The aim of the study was to identify the frequency of isolated pelvic metastasis with the goal of determining the utility of pelvic CT as a surveillance strategy in patients with resected biliary tract cancer (BTC). Study eligibility criteria included patients 18 years or older with BTC who underwent R0 or R1 surgical resection at University of Michigan between 2004 and 2018, with a minimum 6-month disease-free surveillance period. CT and MRI reports were independently graded by two radiologists as positive (organ metastasis, peritoneal carcinomatosis, or enlarged lymph nodes), equivocal (borderline lymph nodes or non-nodular ascites), or negative (absence of or benign findings) in the abdomen and pelvis separately. A 3rd blinded radiologist reviewed all positive and equivocal scans. Clinic notes were reviewed to identify new or worsening signs and symptoms that would warrant an earlier pelvic surveillance scan. A 95% binomial proportion confidence interval was used to find the probability of isolated pelvic metastasis. BTC were anatomically classified as extra-hepatic (distal and hilar) cholangiocarcinoma (38; 25%), intra-hepatic cholangiocarcinoma (57; 38%), and gallbladder cancer (56; 37%). 151 patients met eligibility criteria, of which 123 (81%) had no pelvic metastasis, 51 (34%) had localized upper abdominal metastasis, and 23 (15%) had concomitant abdominal and pelvic metastasis. Median follow-up time was 19.2 months. One (0%) subject with resected BTC (intra-hepatic) developed isolated osseous pelvic metastasis during surveillance (95% CI 0.004–0.1; p = 0.0003). 3 (2%) subjects developed isolated simple ascites (equivocal grade) without concurrent upper abdominal metastasis. Isolated pelvic metastasis is a rare occurrence during surveillance in patients with resected BTCs, and therefore, follow-up pelvic CT in absence of specific symptoms may be unnecessary.

Cross-sectional imaging with contrast-enhanced magnetic resonance imaging (MRI) is routinely performed in patients with hepatocellular carcinoma (HCC) to assess tumor response to locoregional therapy (LRT). Current response assessment algorithms, such as the Liver Imaging Reporting and Data System (LI-RADS) treatment response algorithm (TRA), allow assessment using conventional gadolinium-based extracellular contrast agents (ECA) for accurate tumor response assessment following LRT. MRI with hepatobiliary agents (HBA) allows an acquisition of hepatobiliary phase (HBP), which is proven to increase sensitivity for detection of observations in at-risk patients, particularly for findings

Purpose Intraductal papillary neoplasm of the bile duct (IPNB) is a precursor to invasive carcinoma and is a distinct pathologic diagnosis. The purpose of this study was to evaluate imaging features of IPNB on cross-sectional imaging studies with histopathologic correlation. Materials and methods In this IRB approved, HIPAA compliant retrospective observational analysis of 23 pathology proven IPNB tumors 22 imaging studies were reviewed, 14 CT and 8 MRI scans. Features evaluated in consensus by two subspecialty-trained abdominal radiologists included: presence of specific lesion/mass within the bile duct, location within the biliary tree, size, morphology, enhancement characteristics, and bile duct caliber. Results Majority of the subjects (16/18, 90%) had definite intraluminal mass, of which 7 (39%) had a polypoid mass with upstream diffuse biliary ductal dilation and 5 (28%) had a plaque-like mass with focal stricture and upstream biliary ductal dilatation. 6/18 (33%) subjects had low grade dysplasia, most commonly intestinal subtype, 7/18 (39%) subjects presented with invasive component, commonly pancreaticobiliary subtype, and 5/18 (28%) presented with high grade dysplasia. Conclusion IPNB has increased predilection for extrahepatic bile ducts, commonly presenting as either an intraluminal polypoidal mass with associated upstream biliary ductal dilation or a focal plaque like mass with associated ductal stricture at the site of the tumor.

Nearly 80% of cirrhotic patients diagnosed with hepatocellular carcinoma (HCC) are not eligible for surgical resection and instead undergo local-regional treatment. After therapy for HCC, patients undergo imaging surveillance to assess treatment efficacy and identify potential sites of progressive tumor elsewhere within the liver. Accurate interpretation of posttreatment imaging is essential for guiding further management decisions, and radiologists must understand expected treatment-specific imaging findings for each of the local-regional therapies. Of interest, expected imaging findings seen after radiation-based therapies (transarterial radioembolization and stereotactic body radiation therapy) are different than those seen after thermal ablation and transarterial chemoembolization. Given differences in expected posttreatment imaging findings, the current radiologic treatment response assessment algorithms used for HCC (modified Response Evaluation Criteria in Solid Tumors classification, European Association for the Study of Liver Diseases criteria, and Liver Imaging and Reporting Data System Treatment Response Algorithm) must be applied cautiously for radiation-based therapies in which persistent arterial phase hyperenhancement in the early posttreatment period is common and expected. This article will review the concept of tumor response assessment for HCC, the forms of local-regional therapy for HCC, and the expected posttreatment findings for each form of therapy. Keywords: Abdomen/GI, Liver, MR-Imaging, Treatment Effects, Tumor Response © RSNA, 2020.

Coronary artery disease remains the leading cause of morbidity and mortality in the United States and worldwide. Morphological changes in coronary vasculature can be detected by computed tomography angiography (CTA). Besides qualitative assessment, there has been an increased utilization of quantitative assessment of plaque and stenosis on CTA. For this purpose highly standardized methods have been developed, which are sufficiently reproducible on high quality datasets on a population level. This type of analysis could be potentially useful for not only follow-up of plaque progression but also for enhancing prediction of obstructive coronary arterial lesions and has been validated against current standards such as intra vascular ultrasound, optical coherence tomography, and near-infrared spectroscopy. Studies have demonstrated that types of plaque visualized on CTA have prognostic implications. However, classification of lesions as mild, moderate, or severe might not be enough to answer the clinical question of whether or not the lesion is causing ischemia. Fractional flow reserve computed tomography (CT) and transluminal attenuation gradient are new methods, which have shown great promise in assessment of severity and functional significance of stenosis. Similarly, CT stress testing for assessment of functional significance has been found to be feasible and studies are ongoing to evaluate the accuracy of CT stress perfusion. The promise of cardiovascular CT is to potentially become a comprehensive modality in patients with suspected CAD, by combining plaque imaging, stenosis detection, and the assessment of myocardial ischemia, to provide first-line evaluation in selected patient population.

The presence of calcified plaque in coronary arteries can be quantified by using 0.5-mm isotropic reconstructions from 320-row CT without increased radiation dose. Little is known about reclassification of patients with non-zero Agatston scores and quantitative measures of calcified plaque using 0.5-mm reconstructions.The aim was to compare proportions of zero vs. non-zero Agatston scores (subclinical atherosclerosis) in 0.5-mm isotropic reconstructions vs. standard 3.0-mm and CT angiography (CTA) scans on 320-row CT.Prospectively, we quantified calcified plaque in coronary arteries in 104 patients by using non-contrast-enhanced scans with 0.5 and 3.0 mm. Coronary calcium assessment was determined by 2 observers. Clinically indicated CTA was also performed; coronary calcium assessment findings were compared with CTA. Ranked Wilcoxon test and χ2 test were performed for comparison. Reproducibility for proportion of zero vs non-zero was assessed by κ statistics.Median Agatston score (41.9 [interquartile range (IQR), 3.7-213.6] vs. 5.2 [IQR, 0.0-128.5]), calcium volume (53.6 mm3 [IQR, 8.1-202.3] vs. 5.1 mm(3) [IQR, 0.0-96.8],), and lesion number (10.0 [IQR, 3.5-18.5] vs. 1.0 [IQR, 0.0-6.0]) were significantly higher on 0.5-mm reconstruction (P.0001) than on 3.0-mm reconstruction. More patients with subclinical atherosclerosis were detected on 0.5 mm than on 3.0 mm and CTA scans (76.9% vs. 53.8% vs. 54.8%; P.0001). The κ values for inter-rater agreement were 0.94 and 0.52 on 3.0- and 0.5-mm data sets, respectively. However, when Agatston scores10 were excluded from analysis, the κ value rose to 0.83.Isotropic 0.5-mm reconstruction detected 23.1% and 22.1% more patients with subclinical atherosclerosis than standard 3.0-mm scans and CTA, which may be more sensitive for the detection of subclinical atherosclerosis; its potential clinical utility needs to be validated in large, prospective studies.