There is a theoretical risk of volume overestimation if prostate AP dimension is taken on axial imaging given the anatomic obliquity of the gland on axial plane. This is analogous to slicing a salami sausage diagonally rather than perpendicularly to obtain larger slices. The most recent PI-RADS update (v2.1) now recommends obtaining the anterior-posterior measurement on sagittal imaging to mitigate the theoretical risk of the so called salami effect when using the ellipsoid formula for volume calculations. The authors of the recent article Comparison of PI-RADS Versions 2.0 and 2.1 for MRI-based Calculation of the Prostate Volume found the theoretical salami effect may not be as significant as originally thought, and perhaps slight overestimation of the AP diameter on axial measurements may yield more accurate volume estimates. Future validation studies are needed for to validate their findings. In this contemporary study, there is excellent interreader agreement among radiologist three dimensional measurements-confirming manual calculation can be reliably replicated in practice settings where of software-based segmentation tools are not available.

LEVEL OF EVIDENCE:5 TECHNICAL EFFICACY: Stage 1 J. Magn. Reson. Imaging 2020;52:587-588.

The current algorithm for the imaging diagnosis of hepatocellular carcinoma accurately detects large, progressed tumors displaying the classical imaging features of arterial hyperenhancement with 'washout' and/or 'capsule' appearance. Liver MRI with the relatively newer hepatobiliary agent, gadoxetate disodium, provides information on hepatocellular function in addition to vascularity, facilitates detection of small progressed tumors, as well as early/vaguely nodular tumors, and shows promise for characterizing hepatocellular carcinoma biology. Prediction of tumor grade, presence of biliary and stem cell markers, microvascular invasion, future hypervascularization and post-treatment recurrence have all been studied with gadoxetate disodium-enhanced MRI with encouraging results. Incorporation of gadoxetate disodium-enhanced MRI into standard diagnostic and management algorithms will likely unfold in the future.

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy, and represents a significant global health burden with rising incidence rates, despite a more thorough understanding of the etiology and biology of HCC, as well as advancements in diagnosis and treatment modalities. According to emerging evidence, imaging features related to tumor aggressiveness can offer relevant prognostic information, hence validation of imaging prognostic features may allow for better noninvasive outcomes prediction and inform the selection of tailored therapies, ultimately improving survival outcomes for patients with HCC.

Chronic liver disease, irrespective of cause, can eventually lead to cirrhosis, which is the primary risk factor for developing hepatocellular carcinoma (HCC). In patients with cirrhosis or appropriate risk factors, HCC can be diagnosed by imaging with high specificity using liver imaging reporting and data system v2017, obviating the need for histologic confirmation. Confident recognition of cirrhosis by conventional imaging alone can be challenging, as radiologists are not always provided with the requisite information to determine if the patient has cirrhosis or other risk factors for HCC. Moreover, cirrhosis-associated abnormalities may impair the diagnostic accuracy of imaging for HCC. This article addresses the diagnosis of cirrhosis by non-invasive imaging and the implications of cirrhosis for imaging interpretation and accuracy.

Hepatocellular carcinoma (HCC) is a leading cause of mortality worldwide and a major healthcare burden in most societies. Computed tomography (CT) and magnetic resonance imaging (MRI) play a pivotal role in the medical care of patients with or at risk for hepatocellular carcinoma (HCC). When stringent imaging criteria are fulfilled, CT and MRI allow for diagnosis, staging, and assessment of response to treatment, without the need for invasive workup, and can inform clinical decision making. Owing to the central role of these imaging modalities in HCC management, standardization is essential to facilitate proper imaging technique, accurate interpretation, and clear communication among all stakeholders in both the clinical practice and research settings. The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system that provides standardization across the continuum of HCC imaging, including ordinal probabilistic approach for reporting that directs individualized management. This review discusses the up-to-date role of CT and MRI in HCC imaging from the LI-RADS perspective. It also provides a glimpse into the future by discussing how advances in knowledge and technology are likely to enrich the LI-RADS approach.

Patients with hepatocellular carcinoma (HCC) may be eligible for liver transplantation. Liver transplant candidates with HCC compete for the same deceased donor organs as those without HCC. These scarce organs must be allocated fairly and justly to those who will benefit most. Unlike most other cancers, HCC is often diagnosed noninvasively by imaging without biopsy confirmation. Therefore, radiologists play an important role in diagnosing definite HCC (i.e., LR-5 category) that counts toward staging and determination of liver transplant eligibility. This review explains the conversion of LI-RADS observation categories to organ procurement and transplantation network classes, illustrates the radiologic T-staging systems, reviews selection criteria for liver transplant eligibility, and discusses prioritization of liver transplant candidates with HCC. In addition, this review summarizes imaging requirements, including contrast agents accepted, minimum specifications for dynamic CT or MRI of the liver, and modalities accepted for assessment of extrahepatic spread or metastatic disease in liver transplant candidates with HCC.

Introduction

The use of multi-parametric (MP) MRI to diagnose prostate cancer has been the subject of intense research, with many studies showing positive results. The purpose of our study is to better understand the accessibility, role, and perceived accuracy of MP-MRI in practice by surveying practicing urologists.

Materials and methods

Surveys were sent to 7,400 practicing American Urological Association member physicians with a current email address. The survey asked demographic information and addressed access, accuracy, cost, and role of prostate MRI in clinical practice.

Results

Our survey elicited 276 responses. Respondents felt that limited access and prohibitive cost of MP-MRI limits its use, 72% and 59% respectively. Academic urologists ordered more MP-MRI studies per year than those in private practice (43.3% vs. 21.1%; p<0.001). Urologists who performed more than 30 prostatectomies a year were more likely to feel that an MP-MRI would change their surgical approach (37.5% vs. 19.6%, p-value=0.002). Only 25% of respondents agreed or strongly agreed that MP-MRI should be used in active surveillance. For patients with negative biopsies and elevated PSA, 39% reported MP-MRI to be very useful.

Conclusions

Our study found that MP-MRI use is most prominent among practitioners who are oncology fellowship-trained, practice at academic centers, and perform more than 30 prostatectomies per year. Limited access and prohibitive cost of MP-MRI may limit its utility in practice. Additionally, study participants perceive a lack of accuracy of MP-MRI, which is contrary to the recent literature.

Use of gadoxetate disodium, a hepatobiliary gadolinium-based agent, in patients with chronic parenchymal liver disease offers the advantage of improved sensitivity for detecting hepatocellular carcinoma (HCC). Imaging features of liver observations on gadoxetate-enhanced MRI may also serve as biomarkers of recurrence-free and overall survival following definitive treatment of HCC. A number of technical and interpretative pitfalls specific to gadoxetate exist, however, and needs to be recognized when protocoling and interpreting MRI exams with this agent. This article reviews the advantages and pitfalls of gadoxetate use in patients at risk for HCC, and the potential impact on Liver Imaging Reporting and Data System (LI-RADS) imaging feature assessment and categorization. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:1236-1252.