Biomedical subjects
Publications and source records attributed to T Kokubo.
A case of "innocent" pancreatic gas is reported. The patient had cystic dilatation of the main pancreatic duct limited to the head. Air entered through the patulous ampulla of Vater. Pancreatic gas can be present without abscess or fistula.
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.
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Transient hepatic attenuation differences (THAD) are occasionally noted on dynamic CT in patients with portal vein obstruction, arterioportal shunt, liver tumor, and liver abscess. We report four additional cases of THAD with unreported and/or unexplained etiology.
A fluid-fluid level was observed in three cases of liver hemangioma and in two cases of liver cancer. The patients with hemangioma of the liver did not show enhancement on dynamic CT and the fluid-fluid levels were not detected by ultrasound in two of these patients. Fluid-fluid levels detected by CT but not by ultrasound strongly suggested the diagnosis of nonenhancing hemangioma of the liver.
Four cases of postnecrotic liver scar were examined by dynamic CT or MR imaging or both. Postnecrotic scars appeared as low-density areas on plain CT, showed marked and prolonged enhancement on single level dynamic CT, and became isodense on postcontrast scan. On T2-weighted images, postnecrotic scar were as hyperintense as the spleen. Postnecrotic liver scar is an example of localized attenuation or intensity difference not corresponding to mass lesion. It should be distinguished from mass lesions associated with lobar or segmental attenuation (or intensity) difference of the liver as well as nonmass lesions such as irregular fatty infiltration, radiation hepatitis, and hepatic infarction.
We present a case of intraosseous beta-2-microglobulin amyloidosis of a patient receiving long-term hemodialysis. Magnetic resonance imaging clearly demonstrated intraosseous amyloid deposits as hypointense masses in the femoral head.
In some patients with avascular necrosis of the femoral head (ANFH), an area of signal intensity similar to that of subcutaneous fat tissue is found within or proximal to the hypointense zone of spin echo MR images. We refer to these MR findings as the "fat intensity" sign. This fat intensity sign was positive in 62 (47%) of 133 MR examinations of femoral heads with radiographically proven ANFH; this sign was negative in all hips with other diseases including degenerative joint disease, transient osteoporosis, rapidly destructive coxoarthrosis, and rheumatoid arthritis.
A functional MR study was performed using a 0.064 T permanent magnet MR system. The shoulder joints, elbow joints, hip joints, and knee joints of three volunteers (mean height and weight, 176 cm and 71 kg, respectively) were examined at incremental joint angles in three to eight stages during flexion-extension, abduction-adduction, or pronation-supination movement. Each set of 16 images was obtained in 4 min, 49 s using three-dimensional Fourier transformation methods with gradient echo pulse sequences. The images were evaluated in static mode and sometimes in cine mode. The findings obtained about the physiology of these normal joints was generally compatible with findings previously accumulated in the field of kinesiology. The study suggests that this method can be useful for in vivo study of kinesiology and pathogenesis of diseases and that patients with most types of contracture or deformity can be examined by MR imaging.
We present a case of intrahepatic cystic cholangiocarcinoma with unusual radiologic appearance. Computed tomography, ultrasonography, and magnetic resonance imaging showed a cystic mass with thick wall, that mimicked liver abscess, and cystic or necrotic metastasis. The fluid in the cyst was not mucinous and was negative bacteriologically. Histologic examination showed cholangiocarcinoma with large cavities resulting from necrosis.
A case of retrocaval ureter associated with double inferior vena cava, an exceedingly rare venous anomaly, is reported. This anomaly was correctly diagnosed by CT. CT after intravenous contrast injection showed the double inferior vena cavae on both sides of the abdominal aorta and the right ureter crossing the right inferior vena cava posteriorly. CT is a good diagnostic modality with which to demonstrate such a vascular anomaly, and the clinical usefulness of CT is stressed.
The coronary vein has few variations. We describe a case of coronary vein with an unusual course. In this case, the coronary vein entered the umbilical portion of the left portal vein directly, whereas it usually flows into the portal trunk or splenic vein. The angiographic appearance is presented.
Three cases of multiple, different liver tumors in the same patient were examined with CT and MR imaging. Two patients with coexistent hepatocellular carcinoma and cavernous hemangioma were correctly diagnosed by the following characteristic findings on dynamic CT and/or MR images; spreading and markedly prolonged enhancement in cavernous hemangioma, and the presence of capsule and/or transient diffuse enhancement in hepatocellular carcinoma. The third case of hepatocellular carcinoma and cholangiocarcinoma showed typical findings of hepatocellular carcinoma in one tumor and unusual complex enhancement in the other. CT and MR imaging may enable correct diagnosis to be made even in patients with multiple liver tumors of different kinds.
We developed a multi-purpose catheter for visceral arteriography. The outer diameter of the catheter is 5 Fr and the inner diameter admits a 3 Fr catheter. The catheter is made of soft nylon, with a shaft enforced with stainless wire mesh to improve torque transmission. The head is shaped into a three-dimensional configuration, enabling the superselective catheterization that is required for interventional technique as well as arteriography of first-order branches of the abdominal aorta, e.g. the celiac artery and superior mesenteric artery. Using the catheter, we performed 275 arteriographies in 100 cases (first-order-branch arteriography in 190; superselective technique in 85). Arteriography of first-order branches was successful in all cases. The superselective technique was successful without using any other catheters in 89% of cases.
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.
Transcatheter arterial embolization (TAE) was performed in 20 patients with ruptured hepatocellular carcinoma (HCC). Bleeding was improved in all patients, but only four survived for over three months. Rerupture occurred in seven patients (35%) and the prognosis was extremely poor. TAE should be considered the treatment of choice for ruptured HCC; however, long-term survival was limited to those patients without portal extension of HCC. The severity of rupture also influenced the prognosis.
Among 224 hepatomas treated with transcatheter arterial embolization, ten patients who survived for three years are presented. All cases had nodular lesions and the volume ratio of tumor to liver was less than 10% in nine cases. Eight cases had no large venous extension, however, one had 90% occlusion of the portal trunk and the other had tumor thrombus within the inferior vena cava. Laboratory data showed liver function was largely spared in eight cases, whereas the other two had severe liver cirrhosis. CT and/or angiography showed an increase in tumor volume in eight cases after three years of survival. Beneficial factors for long-term survival and the limitations of embolization are also discussed.
Dynamic magnetic resonance imaging (MRI) was performed in two patients with hepatic tumors (one cavernous hemangioma and one hepatoma). A sequential timed scanning technique with spin echo images (TR: 100 msec; TE: 20 msec; data acquisition time: 26 sec) was used with a bolus injection of 0.05 mmol/kg gadolinium DTPA. Dynamic MRI findings in the two cases were similar to those obtained with dynamic CT and angiography using iodinated contrast medium. Our early experience suggested that the less invasive technique of dynamic MRI could replace conventional dynamic CT in assessing the hemodynamics of hepatic tumors.