Chen-Te Chou

Characterization of cirrhotic nodules with gadoxetic acid-enhanced magnetic resonance imaging: The efficacy of hepatocyte-phase imaging

To evaluate the efficacy of hepatocyte‐phase imaging (HP) in characterization of focal hepatic lesions in cirrhotic liver using gadoxetic acid‐enhanced magnetic resonance imaging (MRI).

Gallbladder torsion: preoperative diagnosis by MDCT.

The patient was a 80-year-old female who was diagnosed as having gallbladder torsion preoperatively. To out knowledge, this is the first reported case diagnosed by CT with a multidetector CT scanner. The abdominal CT showed a V-shape distortion of the extrahepatic ducts, twisting cystic artery with “Whirl’s sign”, distended and enlarged gallbladder with wall hemorrhage. A definitive diagnosis of gallbladder torsion was made by CT preoperatively. If treated surgically, gallbladder detorsion before cholecystectomy is a helpful technique to avoid bile duct injury. This condition should be suspected in elderly women with acute abdominal pain of unknown origin, and MDCT with multiplanar reformation is very useful in making a definitive diagnosis.

Characterization of hyperintense nodules on precontrast T1-weighted MRI: utility of gadoxetic acid-enhanced hepatocyte-phase imaging.

To evaluate the utility of gadoxetic acid‐enhanced hepatocyte‐phase magnetic resonance imaging (MRI) in characterization of T1‐weighted hyperintense nodules within cirrhotic liver.

Non-Invasive Evaluation of Hepatic Fibrosis: The Diagnostic Performance of Magnetic Resonance Elastography in Patients with Viral Hepatitis B or C.

Purpose To compare the accuracy of magnetic resonance elastography (MRE) with that of aspartate aminotransferase-to-platelet ratio index (APRI) for estimating the stage of hepatic fibrosis in patients with chronic hepatitis B virus (HBV) or chronic hepatitis C virus (HCV) infection. Materials and Methods We retrospectively enrolled 160 patients with chronic hepatitis and 25 healthy living liver donors. Fibrosis stage (METAVIR, F0 to F4) was determined histopathologically for all patients. APRI was recorded at the time of histopathologic examination and liver stiffness values were measured on MRE quantitative stiffness maps. The cutoff values, sensitivity, and specificity of MRE and APRI for each fibrosis stage were determined using receiver operating characteristic (ROC) analysis. Results MRE had a significantly greater area under the ROC curve than APRI score for discriminating among METAVIR stages F2-F4. Using a cutoff value of 2.80 kPa, MRE had a sensitivity of 94.4% and a specificity of 97.8% for detecting significant fibrosis (≥F2). There were no significant differences in fibrosis stage between patients with HBV and those with HCV infection. For ≥F2, the cutoffs were 2.47 kPa (100% sensitivity), 2.80 kP (maximum sum of sensitivity and specificity), and 3.70 kPa (100% specificity). Conclusions MRE is a more accurate modality than APRI for detecting significant fibrosis in patients with chronic HBV or HCV infection. Antiviral treatment should be considered in patients with liver stiffness values ≥ 2.8 kPa.

Bilateral retrocaval ureters with IVC duplication

We report a rare case of bilateral retrocaval ureters associated with duplicated inferior renal cava. A 69-year-old woman was sent to our emergency room for abdominal pain. Multidetector computed tomogram with multiplanar reconstruction revealed duplicated inferior renal cavae and the bilateral ureters were positioned behind the duplicated inferior vena cava. To our knowledge, coexistence of bilateral retrocaval ureters and duplicated inferior renal cavae has not been reported in the literature.

Hepatic inflammatory pseudotumor mimicking hepatocellular carcinoma

Inflammatory pseudotumor of the liver is a rare tumor. It has variable clinical presentations and image findings. It can mimic benign or malignant hepatic tumors, and may be difficult to diagnose. We present a case in which a hepatic inflammatory pseudotumor was misdiagnosed as hepatocellular carcinoma because the tumor presented a typical enhancing profile and morphology of hepatocellular carcinoma on computed tomography, and the patient had liver cirrhosis. However, a thicker tumor capsule than that of typical hepatocellular carcinoma was noted while reviewing the computed tomography images. A capsule of inflammatory pseudotumor thicker than that of hepatocellular carcinoma has never been reported in the literature before, and could be an important diagnostic clue to differentiate inflammatory pseudotumor from hepatocellular carcinoma.

The utility of gadoxetic acid-enhanced MR imaging to characterize atypical cirrhotic nodules detected on dynamic CT images.

Purpose To evaluate whether gadoxetic acid (Gd-EOB-DTPA)-enhanced MR images of tumors taken during the hepatocyte-specific phase can aid in the differentiation between hepatocellular carcinoma (HCC) and dysplastic nodules (DNs) in patients with atypical cirrhotic nodules detected on dynamic CT images. Materials and Methods Seventy-one patients with 112 nodules showing atypical dynamic enhancement on CT images underwent gadoxetic acid-enhanced MR imaging (MRI) studies. Using a reference standard, we determined that 33 of the nodules were DNs and that 79 were true HCCs. Tumor size, signal intensity on precontrast T1-weighted images (T1WI) and T2WI, and the pattern of dynamic enhancement on MR images taken in the hepatocyte-phase were determined. Results There were significant differences in tumor size, hyperintensity on T2WI, hypointensity on T1WI, typical HCC enhancement pattern on dynamic MR images, or hypointensity on hepatocyte-phase images between DNs and HCC. The sensitivity and specificity were 60.8% and 87.9% for T2WI, 38.0% and 87.9% for T1WI, 17.7% and 100% for dynamic MR imaging, 83.5% and 84.9% for hepatocyte-phase imaging, and 60.8% and 87.9% for tumor size (threshold of 1.7 cm). Conclusion Gd-EOB-DTPA-enhanced hepatocyte-phase imaging is recommended for patients at high risk of HCC who present with atypical lesions on dynamic CT images.

The value of Gd-EOB-DTPA-enhanced MR imaging in characterizing cirrhotic nodules with atypical enhancement on Gd-DTPA-enhanced MR images

Purpose To evaluate the utility of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in characterizing atypically enhanced cirrhotic nodules detected on conventional Gd-DTPA-enhanced MR images. Materials and methods We enrolled 61 consecutive patients with 88 atypical nodules seen on conventional Gd-DTPA-enhanced MR images who underwent Gd-EOB-DTPA-enhanced MRI within a 3-month period. Using a reference standard, we determined that 58 of the nodules were hepatocellular carcinoma (HCC) and 30 were dysplastic nodules (DNs). Tumor size, signal intensity on precontrast T1-weighted images (T1WI), T2-weighted images (T2WI) and diffusion-weighted images (DWI), and the enhancement patterns seen on dynamic phase and hepatocyte phase images were determined. Results There were significant differences between DNs and HCC in hyperintensity on T2WI, hypointensity on T1WI, hypervascularity on arterial phase images, typical HCC enhancement patterns on dynamic MR images, hypointensity on hepatocyte phase images, and hyperintensity on DWI. The sensitivity and specificity were 79.3% and 83.3% for T2WI, 50.0% and 80.0% for T1WI, 82.8% and 76.7% for DWI, 17.2% and 100% for dynamic MR imaging, 93.1% and 83.3% for hepatocyte phase imaging, and 46.8% and 100% when arterial hypervascularity was combined with hypointensity on hepatocyte-phase imaging. Conclusion Gd-EOB-DTPA-enhanced hepatocyte phase imaging is recommended for patients at high risk for HCC who present with atypical lesions on conventional Gd-DTPA-enhanced MR images.

Efficacy of Transarterial Chemoembolization for Hepatocellular Carcinoma in Interlobar Watershed Zone of Liver: Comparison of Unilateral and Bilateral Chemoembolization

PURPOSE To evaluate the treatment efficacy of unilateral versus bilateral transarterial chemoembolization for hepatocellular carcinoma (HCC) based on whether the tumor is located across the Cantlie line within the watershed zone of the liver. MATERIALS AND METHODS Seventy-seven patients with 87 HCCs located in the watershed zone who underwent complete chemoembolization (unilateral, n = 57 [74%]; bilateral, n = 20 [26%]) were included. Tumors located in the watershed zone were further divided into two groups: tumors across the Cantlie line (type A) and tumors not across the line (type B). Comparison of treatment outcomes of unilateral or bilateral chemoembolization for the two groups was performed. The tumor viability (ie, presence of viable component or tumor progression) and position of the viable component on follow-up computed tomography was recorded. RESULTS Tumor viability rates for type A tumors in the unilateral and bilateral chemoembolization groups were 52.2% and 11.1%, respectively; for type B tumors, they were 23.7% and 11.8%, respectively. The tumor viability rate of type A tumors was significantly higher in the unilateral chemoembolization group than in the bilateral chemoembolization group (P = .05), but there was no significant difference for type B tumors (P > .05). CONCLUSIONS The tumor viability rate of HCC tumors across the Cantlie line was higher with unilateral chemoembolization group than with bilateral chemoembolization. In patients with HCC across the Cantlie line, embolization of bilateral hepatic arteries may achieve better treatment efficacy.

Efficacy of gadoxetic acid-enhanced magnetic resonance cholangiography compared with T2-weighted magnetic resonance cholangiography in patients with liver cirrhosis.

Background Gadoxetic acid is one of the hepatobiliary‐specific agents and so can be used for contrast‐enhanced magnetic resonance cholangiography (CE‐MRC). The aim of our study was to compare the performance of CE‐MRC with that of T2‐weighted magnetic resonance cholangiography (T2W‐MRC), and also to ascertain the effectiveness of both modalities combined for visualizing anatomic structures of the biliary tree in patients with liver cirrhosis. Methods Fifty‐six patients underwent CE‐MRC and T2W‐MRC imaging. In the CE‐MRC studies, hepatobiliary phase images were acquired 20 minutes after contrast injection. Two radiologists first evaluated the T2W‐MRC and CE‐MRC images separately in random order, and then they reviewed both images together 8 weeks later. The readers graded the quality of visualization of each biliary duct and the entire biliary tree (overall rating) using a five‐point scale. Images with a grade of 3 or 4 were considered to provide sufficient visualization for clinical application, and those with a grade of 2 or less were considered to provide insufficient visualization. Laboratory data, Child–Pugh classification, and model for end‐stage liver disease score were also recorded. Results The overall rating of T2W‐MRC was significantly higher than that of CE‐MRC (p < 0.001), although combined T2W/CE‐MRC provided better visualization of biliary segments than T2W‐MRC alone (p = 0.025). There were no significant differences between liver function and the overall rating of CE‐MRC. Conclusion CE‐MRC is not superior to conventional T2W‐MRC with respect to biliary visualization in patients with liver cirrhosis. However, a combination of T2W‐MRC and CE‐MRC provides significantly better visualization of biliary structures than T2W‐MRC alone.