Chansik An

Prediction of the histopathological grade of hepatocellular carcinoma using qualitative diffusion-weighted, dynamic, and hepatobiliary phase MRI.

ObjectivesTo investigate the effectiveness of qualitative diffusion-weighted imaging (DWI), subtraction of unenhanced from arterial phase images, and hepatobiliary phase (HBP) images in estimating the histopathological grade of hepatocellular carcinoma (HCC).MethodsWe retrospectively reviewed gadoxetic acid–enhanced magnetic resonance images of 175 patients with 201 surgically resected HCCs. The signal intensity and its relationship with histopathological grade were assessed for each sequence and a combination of sequences.ResultsThere was a tendency towards higher grades in tumours showing restricted diffusion on DWI (P < 0.001) or arterial enhancement on subtraction imaging (P <0.001), but not hepatocyte-defect on HBP images (P = 0.33). When lesions were divided into three groups based on combined findings on DWI and subtraction imaging, a linear trend was observed between group and grade (P < 0.001). The positive predictive value (PPV) of the combination of no restricted diffusion and no arterial enhancement in predicting well-differentiated HCC was 100%, higher than the PPV of individual findings on DWI (74%) or subtraction imaging (81%).ConclusionsDWI and subtraction imaging are helpful for predicting the histopathological grade of HCC, especially when the two sequences are considered together.Key Points• Predicting the histopathological grade of hepatocellular carcinoma (HCC) preoperatively is important.• Diffusion-weighted imaging (DWI) and subtraction imaging are recently developed MR techniques.• Retrospective study showed DWI and subtraction imaging helps predict HCC grades.• Management of patients with HCC becomes more appropriate.

Liver imaging reporting and data system (LI-RADS) version 2014: understanding and application of the diagnostic algorithm

Liver Imaging Reporting and Data System (LI-RADS) is a system for interpreting and reporting of computed tomography and magnetic resonance imaging of the liver in patients at risk for hepatocellular carcinoma (HCC). LI-RADS has been developed to address the limitations of prior imaging-based criteria including the lack of established consensus regarding the exact definitions of imaging features, binary categorization (either definite or not definite HCC), and failure to consider non-HCC malignancies. One of the most important goals of LI-RADS is to facilitate clear communication between all the personnel involved in the diagnosis and treatment of HCC, such as radiologists, hepatologists, surgeons, and pathologists. Therefore, clinicians should also be familiar with LI-RADS. This article reviews the LI-RADS diagnostic algorithm, and the definitions and management implications of LI-RADS categories.

Single Hepatocellular Carcinoma: Preoperative MR Imaging to Predict Early Recurrence after Curative Resection

PURPOSE To identify magnetic resonance (MR) imaging features that enable prediction of early recurrence (<2 years) after curative resection of hepatocellular carcinoma (HCC) and to derive a preoperative prediction model. MATERIALS AND METHODS This retrospective study was approved by the institutional review board. The requirement to obtain written informed consent was waived. A total of 268 patients who underwent hepatic resection for a single HCC from January 2008 to August 2011 were divided into two cohorts: a training cohort, which was used to derive a prediction model (n = 187), and a validation cohort (n = 81). All MR images from the training cohort were reviewed by two radiologists. A prediction model was constructed by using MR imaging features that were independently associated with early recurrence with use of multiple logistic regression analysis. The performance of the prediction model in the validation cohort was evaluated with respect to discrimination (ie, whether the relative ranking of individual predictions of subsequent early recurrence is in the correct order). RESULTS In the training cohort, four MR imaging features were independently associated with early recurrence: rim enhancement (odds ratio [OR] = 3.83; 95% confidence interval [CI]: 1.39, 10.52), peritumoral parenchymal enhancement in the arterial phase (OR = 2.64; 95% CI: 1.27, 5.46), satellite nodule (OR = 4.07; 95% CI: 1.09, 15.21), and tumor size (OR = 1.66; 95% CI: 1.31, 2.09). A prediction model derived from these variables showed an area under the receiver operating characteristic curve (AUC) of 0.788 in the prediction of the risk of early recurrence in the training cohort. When applied to the validation cohort, this model showed good discrimination (AUC, 0.783). CONCLUSION The prediction model derived from rim enhancement, peritumoral parenchymal enhancement, satellite nodule, and tumor size can be used preoperatively to estimate the risk of early recurrence after resection of a single HCC.

Growth rate of early-stage hepatocellular carcinoma in patients with chronic liver disease.

Background/Aims The goal of this study was to estimate the growth rate of hepatocellular carcinoma (HCC) and identify the host factors that significantly affect this rate. Methods Patients with early-stage HCC (n=175) who underwent two or more serial dynamic imaging studies without any anticancer treatment at two tertiary care hospitals in Korea were identified. For each patient, the tumor volume doubling time (TVDT) of HCC was calculated by comparing tumor volumes between serial imaging studies. Clinical and laboratory data were obtained from the medical records of the patients. Results The median TVDT was 85.7 days, with a range of 11 to 851.2 days. Multiple linear regression revealed that the initial tumor diameter (a tumor factor) and the etiology of chronic liver disease (a host factor) were significantly associated with the TVDT. The TVDT was shorter when the initial tumor diameter was smaller, and was shorter in HCC related to hepatitis B virus (HBV) infection than in HCC related to hepatitis C virus (HCV) infection (median, 76.8 days vs. 137.2 days; P=0.0234). Conclusions The etiology of chronic liver disease is a host factor that may significantly affect the growth rate of early-stage HCC, since HBV-associated HCC grows faster than HCV-associated HCC.

Assessment of preoperative magnetic resonance imaging staging in patients with hepatocellular carcinoma undergoing resection compared with the seventh American Joint Committee on Cancer System.

ObjectivesThe aim of this study was to compare the prognostic utility of a staging system using magnetic resonance imaging (MRI) with the seventh American Joint Committee on Cancer (AJCC) staging system in patients with hepatocellular carcinoma (HCC) who underwent hepatic resection. Materials and MethodsA total of 175 consecutive patients with HCC who underwent curative hepatic resection after MRI between January 2000 and December 2007 were analyzed. In lieu of microvascular invasion, which is used by the AJCC staging system, we devised an MRI staging system in which a size criterion of 2 cm was used to differentiate between tumor stages 1 and 2. All patients were retrospectively staged using the seventh AJCC staging system and the preoperative MRI staging system. Differences in disease-free and overall survival rates between different stages by the MRI and AJCC staging systems were analyzed using the Kaplan-Meier method with log-rank testing. The predictive accuracy of the 2 staging systems was directly compared using the time-dependent receiver operating characteristic curve analysis. ResultsMedian follow-up period was 222.9 weeks. During the follow-up period, 74 (42.3%) patients experienced tumor recurrence and 22 (12.6%) died. The median disease-free survival and overall survival were 131.1 and 222.9 weeks, respectively. Both staging systems were excellent for the prediction of disease-free survival across different tumor stages but failed to predict overall survival differences between stages 1 and 2. For disease-free and overall survivals, the time-dependent receiver operating characteristic curve analysis revealed no significant differences in predictive accuracy between the 2 staging systems. ConclusionA preoperative MRI staging system using a size threshold instead of microvascular invasion may predict the prognosis of HCC patients undergoing hepatic resection as accurately as the seventh AJCC tumor-node-metastasis staging system.

Diffusion-Weighted MRI in Intrahepatic Bile Duct Adenoma Arising from the Cirrhotic Liver

A 64-year-old male patient with liver cirrhosis underwent a CT study for hepatocellular carcinoma surveillance, which demonstrated a 1.4-cm hypervascular subcapsular tumor in the liver. On gadoxetic acid-enhanced MRI, the tumor showed brisk arterial enhancement and persistent hyperenhancement in the portal phase, but hypointensity in the hepatobiliary phase. On diffusion-weighted MRI, the tumor showed an apparent diffusion coefficient twofold greater than that of the background liver parenchyma, which suggested that the lesion was benign. The histologic diagnosis was intrahepatic bile duct adenoma with alcoholic liver cirrhosis.

Diagnostic accuracy of prospective application of the Liver Imaging Reporting and Data System (LI-RADS) in gadoxetate-enhanced MRI

ObjectivesTo evaluate the diagnostic performance of the LI-RADS (v2014) on gadoxetate-enhanced MRI prospectively applied in actual practice.MethodsWe retrospectively reviewed the prospectively written radiology reports of 143 treatment-naïve at-risk patients who underwent gadoxetate-enhanced liver MRI from January to December 2014, and identified 202 hepatic observations categorized using the LI-RADS. The diagnostic performances of LI-RADS categories for hepatocellular carcinoma (HCC) and hepatic malignancy were calculated.ResultsTwenty (69.0 %) of 29 LR-4, 73 (97.3 %) of 75 LR-5, and all of five (100 %) LR-5V observations were HCCs. The remaining two (2.7 %) LR-5 observations were combined hepatocellular-cholangiocarcinomas, while 10 (76.9 %) of 13 LR-M observations were HCCs. The sensitivity and specificity of LR-5/5V for HCC were 60.5 % and 97.3 %, respectively. Including LR-M in the diagnostic criteria for HCC increased sensitivity (68.2 %, p = 0.002) but decreased specificity without statistical significance (93.2 %, p = 0.154). LR-5/5V/M yielded sensitivity of 68.9 % and specificity of 100.0 % for hepatic malignancy.ConclusionsLI-RADS v2014 was successfully applied on gadoxetate-enhanced MRI in clinical practice. LR-5/5V was the most specific diagnostic measure for HCC, but most LR-M observations were HCCs and a considerable portion of non-HCC malignancies were categorized as LR-4 or LR-5.Key Points• LR-5/5V provided a highly specific diagnosis for HCC.• Half of non-HCC malignancies were categorized as LR-4 or LR-5.• The majority of LR-M observations were finally diagnosed as HCCs.• More sensitive diagnosis of HCC was feasible with LR-5/5V/M on gadoxetate-enhanced MRI.• Observations in either LR-5/5V or LR-M categories were definitely malignant.

Diagnosis of hepatocellular carcinoma with gadoxetic acid-enhanced MRI: 2016 consensus recommendations of the korean society of abdominal radiology

Diagnosis of hepatocellular carcinoma (HCC) with gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) poses certain unique challenges beyond the scope of current guidelines. The regional heterogeneity of HCC in demographic characteristics, prevalence, surveillance, and socioeconomic status necessitates different treatment approaches, leading to variations in survival outcomes. Considering the medical practices in Korea, the Korean Society of Abdominal Radiology (KSAR) study group for liver diseases has developed expert consensus recommendations for diagnosis of HCC by gadoxetic acid-enhanced MRI with updated perspectives, using a modified Delphi method. During the 39th Scientific Assembly and Annual Meeting of KSAR (2016), consensus was reached on 12 of 16 statements. These recommendations might serve to ensure a more standardized diagnosis of HCC by gadoxetic acid-enhanced MRI.

Prognostic role of magnetic resonance imaging vs. computed tomography for hepatocellular carcinoma undergoing chemoembolization.

Computed tomography (CT) and magnetic resonance imaging (MRI) play important roles in diagnosis and staging of hepatocellular carcinoma (HCC). However, prognostic roles of radiological characteristics are not yet determined.

Usefulness of the Tensile Gallbladder Fundus Sign in the Diagnosis of Early Acute Cholecystitis

OBJECTIVE The purpose of this article is to evaluate the usefulness of the tensile gallbladder fundus sign on CT in diagnosing early acute cholecystitis. MATERIALS AND METHODS The tensile gallbladder fundus sign on CT is defined as the absence of gallbladder fundus flattening by the anterior abdominal wall due to increased gallbladder pressures. Between October 2010 and March 2012, 222 patients with confirmed diagnoses of acute cholecystitis by surgery or follow-up imaging studies underwent CT scans in the emergency department because of right upper quadrant pain. Two radiologists retrospectively reviewed all CT images to determine the presence of the tensile gallbladder fundus sign and other CT findings previously reported to be suggestive of acute cholecystitis. Diagnostic performances were calculated and analyzed using pairwise comparisons of receiver operating characteristic curves. The kappa statistic was calculated to evaluate the interobserver agreement. RESULTS Using the diagnostic criteria in which acute cholecystitis is defined as the presence of three or more classic CT findings, the addition of the tensile gallbladder fundus sign increased the area under the receiver operating characteristic curve (Az) value from 0.693 to 0.739 (p = 0.003). In the subgroup of 91 patients with no other CT features suggestive of acute cholecystitis, the sensitivity, specificity, and Az value of the tensile gallbladder fundus sign for acute cholecystitis were 74.1%, 96.9%, and 0.855, respectively. Interobserver agreement was good with the tensile gallbladder fundus sign (κ = 0.721). CONCLUSION The tensile gallbladder fundus sign may be useful for diagnosing acute cholecystitis, especially in the early stage when other CT findings are absent.