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Biomedical subjects

N Yashiro

Publications and source records attributed to N Yashiro.

At least 91 records · Page 5Linked to original sources

Computed tomography of cavernous hemangioma of the liver.

Twelve cases of hepatic hemangioma were examined by computed tomography (CT). Dense accumulations of rapidly injected contrast material in or near the periphery of the lesions were demonstrated in early postcontrast scans. They invaded the area of low density and diminished in attenuation value with time. This marked decrease of the low density area noticed in the precontrast scan was also seen in the later postcontrast scan. These findings were recognized in all 10 cases of hemangioma examined with contrast enhancement, while no cases of hepatoma showed such a peripheral high density zone. Most hepatic hemangiomas could be correctly diagnosed by CT alone.

Adult↗

Computed tomography of gallbladder carcinoma.

Twenty-seven gallbladder carcinomas were examined by computed tomography (CT). All patients had abnormal CT findings, suggesting a gallbladder lesion in 26. Based on the major CT findings, gallbladder cancer was classified as "massive," "thickened wall," or "intraluminal." Twenty cases were diagnosed correctly as cancer: on retrospect, definite findings of gallbladder cancer were observed in 24 and equivocal or misleading signs in 3. Some cases of chronic cholecystitis and liver tumor were difficult to differentiate from gallbladder cancer. Direct hepatic extension was easily seen, but lymph-node metastases and bile-duct extension were difficult to distinguish.

Adenocarcinoma↗

Usefulness of gradient-echo T2*-weighted MR imaging in evaluation of transorbital penetrating cerebral injury.

Transorbital penetrating cerebral injury can cause severe morbidity if not identified and treated. After the removal of the object and without the clinical information, even the chance of suspicion of penetrating cerebral injury might be missed in the first investigation. We report a case of transorbital penetrating cerebral injury caused by a metal rod and diagnosed by MRI including gradient-echo T2*-weighted imaging.

Accidental Falls↗

MR imaging of portal vein thrombus in hepatocellular carcinoma.

This report describes the magnetic resonance (MR) demonstration of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma (HCC). In two cases of HCC with PVTT diagnosed by angiography, MR demonstrated PVTT as areas of increased MR signal in the portal vein. Our limited experience suggests the potential utility of MR imaging for diagnosis of PVTT.

Carcinoma, Hepatocellular↗

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.

Adenoma, Bile Duct↗

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.

Adult↗

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.

Adult↗

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.

Carcinoma, Hepatocellular↗

Fast spin echo imaging with suspended respiration: gadolinium enhanced MR imaging of liver tumors.

Magnetic resonance (MR) imaging of 43 patients with hepatic tumor was performed during suspended respiration using a fast scan spin echo (SE) technique (SE 200/40) with a single excitation. The resulting images were superior in terms of image quality to conventional ones. Due to the lack of soft tissue contrast, 38 patients received Gd-diethylenetriaminepentaacetic acid (DTPA) at 0.05 mmol/kg and serial scanning (CE-MR) was repeated. Twelve of 14 hepatomas showed isointensity or slightly reduced intensity compared with the liver in unenhanced MR. All metastases (nine patients) showed low signal intensity that was statistically significant (p less than 0.001) in differentiating between hepatomas and metastatic liver tumors. With contrast enhanced MR, both hepatomas and metastases showed changes that cannot be further classified until more cases have been examined. In all 12 cavernous hemangioma cases, Gd-DTPA pooling was observed with extremely high contrast, which was a pathognomonic sign. In fact, four cavernous hemangiomas in two patients with a diameter of 1.0 cm were successfully imaged.

Adult↗

CT and MR imaging of fatty tumors of the liver.

The presence of fat in hepatic masses narrows the range of differential diagnoses down to hepatic angiomyolipoma, lipoma, adenoma, hepatoma, metastatic fatty tumors of the liver, focal fatty infiltration of the liver, and extrahepatic fatty masses such as intraperitoneal implants from malignant teratomas, and packed omentum. We report six hepatic tumors containing fat (lipoma, hepatocellular carcinoma, and calcified mass with fat-fluid level) with CT and magnetic resonance (MR) imaging. The distribution of fat was diffuse in the lipomas and some hepatocellular carcinomas and localized in other hepatocellular carcinomas and fat-fluid masses. The density ranged from - 100 to 0 HU. High intensity areas on both T1- and T2-weighted MR images corresponded to the hypodense areas on CT.

Adult↗

Diffuse intrasinusoidal liver metastasis of small cell lung cancer causing fulminant hepatic failure: CT findings-a case report.

A 65-year-old man with small cell lung cancer treated with two courses of chemotherapy manifested appetite loss and abdominal distention 10 days before admission. Helical CT scanning of the abdomen and pelvis disclosed marked hepatomegaly without any visible nodular lesion in the hepatic parenchyma. He died of severe liver dysfunction with multiorgan failure on the 20th hospital day. Autopsy revealed diffuse invasion of tumor cells into the sinusoid throughout the liver.

Aged↗