T. Gabata

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.

Transjugular intrahepatic portosystemic shunt after previous recanalization of a chronically thrombosed portal vein via a transmesenteric approach

We report a cirrhotic patient with complete occlusion of the portal vein with marked cavernous transformation due to chronic thrombosis in whom a transjugular intrahepatic portosystemic shunt (TIPS) was success-fully created after direct minilaparotomy mesenteric vein catheterization, lysis and aspiration of the thrombus, and stenting in the portal vein. The methods used, we believe, provide a new technique for performing TIPS in chronically thrombosed portal veins in which previously no effective surgical therapeutic options were available.

Peribiliary cysts in cirrhotic liver: observation on computed tomography.

Abstract.Background: To analyze the frequency and number of suspected peribiliary cysts in cirrhotic liver on computed tomography (CT). Methods: Three hundred forty-six cases with clinically diagnosed liver cirrhosis (LC) and 307 cases with clinically diagnosed non-LC were subjected to the study. The frequency and number of suspected peribiliary cysts on CT were compared between the two groups. The existence of peribiliary cysts was suggested when a cyst was observed around the second- to fourth-order branches of the intrahepatic portal vein. Results: Peribiliary cysts were suggested on CT in 31 of 346 cirrhotic livers (9.0%) and 10 of 307 noncirrhotic livers (3.3%). This difference in the frequency of peribiliary cysts was statistically significant (χ2, p < 0.01). Multiple peribiliary cysts were seen in 71% of cirrhotic patients with peribiliary cyst. The size of peribiliary cysts was smaller than 1.5 cm in diameter. Conclusion: Peribiliary cyst is radiologically observed more frequently in cirrhotic liver than in noncirrhotic liver and is occasionally multiple.

Peritumoral spared area in fatty liver: correlation between opposed-phase gradient-echo MR imaging and CT arteriography.

AbstractBackground: The purpose of the present study was to evaluate the magnetic resonance findings of a spared area of fatty liver caused by hepatic tumors and clarify the etiology of this phenomenon by computed tomographic (CT) arteriography. Methods: Six patients with hepatic tumors (metastases from colon cancer, n= 3; breast cancer, n= 2; hepatocellular carcinoma, n= 1) were examined. In-phase (IP) and opposed-phase (OP) T1-weighted spoiled gradient-echo images were obtained. CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) were also performed. Pathologic confirmation was obtained in three patients with metastases from colon cancer. Results: In all six patients, peritumoral ringlike or wedge-shaped hyperintense areas in relation to the tumor and the surrounding steatotic liver parenchyma were clearly visualized on OP images alone. This area appeared as a perfusion defect on CTAP and ringlike or wedge-shaped enhancement on CTHA. Pathologically, the peritumoral hyperintense areas on OP images were compatible with the spared area of fatty liver. Conclusion: A peritumoral spared area can be demonstrated with OP images. The etiology of the phenomenon is correlated with decreased portal flow and increased arterial flow in the peritumoral hepatic parenchyma.

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.

MR imaging of focal splenic extramedullary hematopoiesis in polycythemia vera: case report.

We report a case with focal mass–like lesion of the spleen in polycythemia vera. Magnetic resonance imaging of the lesion showed homogeneous hyperintensity on T2-weighted images, with progressive enhancement on dynamic magnetic resonance images after bolus injection of gadolinium. The magnetic resonance features of focal splenic extramedullary hematopoiesis have not been previously reported.

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.

Intrahepatic biliary calculi: correlation of unusual MR findings with pathologic findings

We report a case of intrahepatic biliary calculi. A localized dilated intrahepatic duct of the left lateral segment of the liver was filled with material that showed marked hyperintensity on T1- and T2-weighted magnetic resonance (MR) images. These MR findings are unusual for intrahepatic stones. Pathologically, the stones were muddy bilirubin calculi, the chemical and physical characteristics of which are surmised to have been the cause of the unusual MR findings.

Imaging of multistep human hepatocarcinogenesis.

In Japan, there are approximately 32 000 deaths (∼30 deaths per 100 000) per year due to hepatocellular carcinoma (HCC), and it is the third most common cancer in men and fifth in women. Approximately 90% of them are associated with chronic liver diseases due to hepatitis C or B virus infection. Therefore, it has become possible to detect small early stage HCC by the periodic screening in these high‐risk patients group. During the screening imaging diagnosis of HCC, various kinds of hepatocellular nodules are also frequentlydetected. To characterize them is very important for the early diagnosis and treatment of HCC. For this purpose, it is necessary to understand the concept of multistep hepatocarcinogenesis and the sequential changes of imaging findings.

Cystic duct remnant carcinoma with widespread invasion along the extrahepatic bile duct wall: dynamic CT findings

AbstractWe report a case of remnant cystic duct carcinoma with widespread invasion along the common bile duct wall. Thin-slice dynamic computed tomography showed circumferential wall thickening of the extrahepatic bile duct (from the common hepatic duct to the intrapancreatic common bile duct) and the remnant cystic duct. Pathologically, the extrahepatic bile duct wall was thickened due to submucosal tumor infiltration by cystic duct papillary adenocarcinoma.