Yuji Itai

Case report: Enormous intrahepatic communication between the portal vein and the hepatic vein

A case of enormous intrahepatic shunt between the portal vein and the hepatic vein is described. The lesion was successfully treated by embolisation using stainless steel coils on two occasions, after demonstration by percutaneous transhepatic portography (PTP).

MR Imaging of hepatocellular carcinoma

Forty-two patients with hepatocellular carcinoma (HCC) were examined by magnetic resonance (MR) imaging. The presence of tumor was suggested in 41 of 42 cases by a high-intensity area on T2 weighted spin-echo (SE) images with a repetition time (TR) of 1.6 s. Specific findings of HCC such as the presence of a capsule, mosaic pattern, and tumor thrombus in major veins were noted in 10, two, and seven cases, respectively. In six cases the tumor pattern changed from a well-defined mass to an irregular, ill-defined one according to pulse sequence (SE: echo time 35 and 70 ms; TR 1.6 and 0.4 s). In our early experience MR was almost equal to conventional X-ray CT in the detection of main or daughter lesions and in the determination of extent and characterization of HCC.

Pancreatic Cysts Caused by Carcinoma of the Pancreas: A Pitfall in the Diagnosis of Pancreatic Carcinoma

Pancreatic cysts were diagnosed on computed tomography (CT) in 6 (8%) of 73 histologically proven pancreatic carcinomas. In three of a total of seven cases studied, the initial CT diagnosis was pancreatitis. The CT features of cysts secondary to pancreatic carcinoma were identical to those of pseudocysts in pancreatitis. All cases had masses of varying sizes suggestive of carcinoma or pancreatitis. Even in retrospect, two cases were difficult to differentiate from pancreatitis with pseudocysts. Our results indicate that whenever pancreatic cysts are encountered in patients of cancer age without a history of pancreatitis, further examinations including percutaneous aspiration biopsies should be performed to exclude malignancy.

MR imaging of hepatoma treated by embolization

The magnetic resonance findings of two hepatomas treated by embolization are presented. The T2-weighted spin echo images showed an increase in signal intensity in the tumor after embolization. This phenomenon corresponded to a decrease in tumor density on CT and to necrosis observed histologically. Magnetic resonance also demonstrated gas bubbles as low signal foci within the embolized tumor.

Portosystemic collaterals on MR imaging

Fourteen patients with various portosystemic collaterals (seven esophageal varices, three paraumbilical veins, two splenorenal shunts, and two mesenteric varices) were imaged with magnetic resonance (MR) imaging using a superconducting imager. Collateral pathways were demonstrated as tortuous structures of no or low signal intensity on spin-echo image, and flow related enhancement did not cause any difficulty in evaluation. Direct sagittal images are especially useful for paraumbilical vein and coronal images for esophageal and mesenteric varix. The clinical role of MR in the assessment of portosystemic collaterals is discussed also in comparison with CT and ultrasound.

Lobar Intensity Differences of the Liver on Mr Imaging

Differences in signal intensity involving lobes of the liver were noted in seven cases of liver tumor. The clinical significance and possible cause of these differences in lobar intensity are discussed.

CT and MR appearance of focal nodular hyperplasia of the liver in children with biliary atresia

Two children with biliary atresia are described in whom focal nodular hyperplasia of the liver occurred following portoenterostomy. The lesions were low-or iso-dense on unenhanced CT and became hypodense post-contrast enhancement. There was normal 99mTc phytate on hepatic colloid scintigraphy. On T2-weighted spin echo MR images, there was increased signal intensity within the masses, and the surrounding liver parenchyma was divided by linear septa in one of the two cases.

Hepatic cavernous hemangioma in patients at high risk for liver cancer.

Cavernous hemangioma of the liver occurring in patients at high risk for liver cancer has been reviewed. Twenty-four patients with hemangioma were encountered during the past 4 years. Five lesions over 3 cm in diameter were correctly diagnosed with enhanced CT alone. Definite CT findings were however obtained in only 6 out of 19 lesions smaller than 3 cm in diameter. Ultrasonography was the most sensitive method for picking up small liver tumors even when compared with angiography, but the findings were non-specific (an echogenic mass was noted in 14 of the 19 lesions). Magnetic resonance imaging (MRI) had almost the same sensitivity as ultrasound in detecting small hemangiomas, and a prolonged T2 was highly suggestive of the diagnosis (T2 over 80 ms in 8 of 11 lesions). The results suggest that combined use of non-invasive diagnostic modalities has sufficient reliability to make a diagnosis of cavernous hemangioma even in small hepatic lesions, in patients at high risk for liver cancer.

Pseudomyxoma peritonei with progressive calcifications: CT findings

Development of abdominal calcifications due to pseudomyxoma peritonei is rare. The authors present three cases whereby computed tomographic (CT) studies during or after chemotherapy for pseudomyxoma peritonei demonstrated development and progression of punctate calcifications in the abdomen. The clinical and CT findings of these cases are presented together with a brief review of the pertinent literature.

Imaging Diagnosis with Computed Tomography

The image obtained by X-ray computed tomography (CT) is a computer-assisted reconstruction of averaged X-ray attenuation in the individual pixel of the matrix. Therefore, CT reflects essentially the same information as the conventional X-ray photograph. The advantage and characteristics of CT are seen in better contrast resolution in a true tomogram. With the conventional film-screen system, a normal organ and its neoplasm show a similar X-ray attenu-ation and cannot be distinguished without the aid of contrast material. CT is capable of distin-guishing a 0.5% difference in contrast expressed in Hounsfield units or numbers (which are set at 0 for water and —1000 for air), whereas the conventional film-screen system can barely distinguish ascites from the liver (about 6% contrast).