Osamu Matsui

Delayed MR imaging of the liver: correlation of delayed enhancement of hepatic tumors and pathologic appearance

Abstract.Background: The value of delayed magnetic resonance (MR) imaging (6 min) and ultradelayed MR imaging (1–4 h) for differentiating of hepatic tumors was studied. Methods: Postcontrast delayed and ultradelayed MR images were obtained after administration of 0.1 mmol/kg of Gd-DTPA in 30 patients with various malignant hepatic tumors. Results: Delayed enhancement in the center of the tumors was seen in 13 patients on the delayed MR images and in 22 patients on the ultradelayed MR images. On the ultradelayed images, peripheral hypointense rim was seen in 12 patients and central focal hypointense area was seen in eight patients. Pathologically, the portion showing delayed enhancement corresponded to abundant fibrous stroma, the hypointense rim to rich proliferation of tumor cells, and the central hypointense areas to coagulative necrosis. Conclusion: Ultradelayed MR imaging can characterize different tissue components within various hepatic tumors.

Differentiation of hypervascular hepatic pseudolesions from hepatocellular carcinoma: value of single-level dynamic CT during hepatic arteriography.

PURPOSE The purpose of our study was to assess the efficacy of single-level dynamic CT during hepatic arteriography (D-CTA) in the differentiation between hypervascular hepatocellular carcinoma (HCC) and hypervascular pseudolesion. METHOD D-CTA was performed in nine cases with HCC and nine cases with pseudolesion. Findings on D-CTA were retrospectively analyzed. RESULTS The transition of the stain of pseudolesion on D-CTA was divided into three phases: (1) inflow of the contrast material into the portal vein within the lesion, (2) lesion staining, and (3) fading out of the stain; that of HCC was divided into four phases: (1) inflow of CM into tumor, (2) tumor staining, (3) inflow of CM into the adjacent liver, and (4) coronal stain of adjacent liver. The coronal stain was seen in all HCCs but not in any pseudolesions. CONCLUSION The present study suggest that D-CTA is a helpful option in the differentiation between HCC and pseudolesion.

Gallbladder varices : demonstration of direct communication to intrahepatic portal veins by color Doppler sonography and CT during arterial portography

Abstract. Gallbladder varices were correctly diagnosed by color Doppler sonography and computed tomography during arterial portography (CTAP) in two patients with portal vein thrombosis. One patient with multiple hepatocellular carcinomas showed extrahepatic and intrahepatic portal vein occlusion by a tumor thrombus. The other patient, with liver cirrhosis, had a portal vein thrombosis. Color Doppler sonography clearly showed the portal vein occlusion, cavernous transformation of collateral veins, and gallbladder varices that drained into the intrahepatic portal venous branches. The intrahepatic portal venous branch, connecting to the gallbladder varices, exhibited reverse flow from the periphery to the hilum of the liver. CTAP also demonstrated gallbladder varices communicating directly with the intrahepatic portal vein branches in both patients. Gallbladder varices developed as a venous collateral because of extrahepatic portal vein occlusion. Color Doppler sonography and CTAP are useful for detecting these varices and planning biliary surgery in patients with portal vein thrombosis.

CTAP in Budd-Chiari syndrome: evaluation of intrahepatic portal flow

Abstract.Background: To assess the intrahepatic portal flow in patients with Budd-Chiari syndrome (BCS) by computed tomography (CT) during arterial portography (CTAP). Methods: Five patients with BCS [with (n = 3) and without (n = 2) inferior vena cava (IVC) obstruction] underwent both CTAP and postcontrast CT following CTAP. CTAP and postcontrast CT after angioplasty were also performed in one patient. Findings on CTAP and postcontrast CT were analyzed retrospectively. Results: Patients with IVC obstruction and a patent large hepatic vein showed homogeneous hepatic enhancement on CTAP. Patients without IVC obstruction and with no patent large hepatic veins showed heterogeneous hepatic enhancement, which consisted of patchy enhancement and more definite enhancement in the central part of the liver. On postcontrast CT, the patchy enhancement was enlarged compared with that on CTAP in these patients. The heterogeneous hepatic enhancement became homogeneous in the patient who underwent angioplasty. Conclusion: We suggest that the more marked the blood congestion, the more heterogeneous the hepatic enhancement becomes on CTAP. Heterogeneous hepatic enhancement on CTAP is seen in such cases without any patent hepatic veins.

Pseudolesion in segment IV of the liver on MRI: prevalence and morphology in 250 cirrhotic livers compared with 250 normal livers.

PURPOSE The goal of our study was to assess the prevalence of pseudolesion in segment IV of the liver on MRI in patients with and without liver cirrhosis. METHOD Patients were divided into three groups: 10 patients with angiographically confirmed aberrant gastric venous drainage and liver cirrhosis (Group 1), 250 consecutively selected patients with liver cirrhosis (Group 2), and 250 with normal liver (Group 3). The signal intensity of pseudolesion in segment IV on T1- and T2-weighted MRI in the 510 patients was analyzed. RESULTS In Group 1, five pseudolesions were visible and hyperintense on T1-weighted images. On T2-weighted images, four were visible and hypointense. In Group 2, 11 were seen (4.4%). All were hyperintense on T1-weighted images. Five were hypointense on T2-weighted images. In Group 3, one pseudolesion was seen (0.4%). CONCLUSION The prevalence of pseudolesion in segment IV on MRI is higher in liver cirrhosis than in normal liver. The lesion is hyperintense on T1-weighted images when visible.

Giant hyperplasia of the caudate lobe of the cirrhotic liver: correlation with an anomaly of the caudate portal branch

Different imaging appearances of giant hyperplastic change of the caudate lobe of the liver are presented in a patient with liver cirrhosis. The mass like caudate lobe was isoechoic on ultrasound, hypodense on postcontrast computed tomography (CT), hyperintense on T1-weighted magnetic resonance, images and isointense on T2-weighted images. These imaging findings are similar to those of dysplastic nodule in cirrhotic liver. The caudate lobe received normal portal flow on CT during arterial portography, but superior mesenteric arteriography showed precocious or early division of the caudate portal branch. We suspect that caudate hyperplastic change may be correlated to anomalous caudate portal vein branch.

Fatty infiltration of the liver distal to a metastatic liver tumor

Abstract. We report a case of focal fatty infiltration of the liver parenchyma adjacent to a metastatic liver tumor from an islet cell tumor. The decreased portal flow by the tumor and insulin produced by the tumor cells might be causes of focal fatty infiltration.