Biomedical subjects
Publications and source records attributed to K Ohtomo.
We present a case of hemorrhage into an intralobar pulmonary sequestration in which magnetic resonance imaging (MRI) clearly demonstrated a mass of high signal intensity on both T1- and T2-weighted images, indicative of hemorrhage.
Among 123 cases of hepatic cavernous hemangioma examined by CT, MRI, and/or angiography, four were considered atypical from the viewpoint of differential diagnosis on individual modalities: two cases of nonenhanced tumor, one of diffuse, homogeneous staining and rapid disappearance associated with arterioportal shunt on dynamic CT and/or angiography, and one with a large, internal, high-intensity area on MRI. Although hepatic cavernous hemangiomas are usually accurately diagnosed by the various imaging modalities, some show atypical features.
The potential utility of spectroscopic imaging by dephasing amplitude changing (SIDAC) was evaluated in fatty infiltration in rats induced by cholesterol and ethanol. There was an excellent correlation between the in vivo fat-to-water ratio obtained from SIDAC and that in liver specimens from in vitro measurement (r = 0.97). SIDAC is a promising method for semiquantitative analysis of fatty infiltration of the liver.
Sixty-four pelvic CT studies of 38 patients with pelvic malignancies were obtained at various times (21 to 678 days) following fast neutron radiotherapy. Multiple scans (2 to 3) were available in 19 cases. Fractionated neutron radiotherapy was delivered over four to seven weeks to a total dose of 54 Gy to 60 Gy photon equivalent. Radiation-induced changes on CT were symmetrical thickening of the perirectal fascia (87%), widening of the presacral space (82%), and thickening of the walls of the bladder and rectum (21% and 11%, respectively). Serial CT studies showed that these changes became stable after 12 weeks from radiotherapy in 13 of 14 patients (93%). CT manifestations of radiation-induced changes in the pararectal area were rather regular and would be easy to differentiate from local recurrence or secondary disease.
Five cases with primary Budd-Chiari syndrome due to membranous obstruction of the hepatic segment of the inferior vena cava were examined by CT. In all cases, CT demonstrated caudate lobe enlargement, reticular low density within the liver parenchyma, splenomegaly, and collaterals via the ascending lumbar veins and azygous system. Pathological study revealed liver cirrhosis or fibrosis in all cases. In two cases, calcification was shown in the region of the hepatic segment of the inferior vena cava. Our results suggested that the CT appearance of primary Budd-Chiari syndrome was rather characteristic and useful in diagnosis, although membranous obliteration could not be shown directly on CT.
Four cases of traumatic renal artery occlusion are reported. A direct blow to the abdomen was considered to have caused renal artery occlusion in two cases. They were severely injured and had macroscopic hematuria. Aortography revealed an abrupt cut-off type of obstruction of the renal artery. In the other two, a rapid decelerating-type of injury resulted in damage to the intima of the renal artery. They showed almost no outward signs of injury and no macroscopic hematuria. Aortography disclosed a tapered occlusion of the renal artery. CT showed the rim sign between the seventh day and sixth week before the compromised kidney became apparent. It had disappeared by the time follow-up CT revealed contraction. One patient developed hypertension, which subsided after nephrectomy. CT findings of the patient suggested the possibility of predicting hypertension as a sequelae of acute renal artery occlusion.
Intraarterial digital subtraction arteriography (IADSA) was performed in 94 patients with hepatic tumors and evaluated on the following subjects: 1) visualization of small arteries in arterial phase, compared with film study, 2) visualization of faint tumor stains in hepatogram phase, compared with film study, 3) visualization of portal venous branches by intraarterial digital subtraction portography (IADSP). Interventional angiography was performed in 76 patients. Contrast dose and injection rate of IADSA was approximately a third of film study without dilution. The position of the catheter was identical in IADSA and film study. IADSPs were performed with 15-20 ml of 76% Urografin, which was injected into the superior mesenteric artery at the rate of 5 ml/sec after infusion of prostaglandin E1. Comparison in arterial phase of 67 patients showed 24 (36%) IADSAs were equal to film study. Thirty-nine (58%) were inferior but adequate for the diagnosis of hepatic tumors. Comparison in hepatogram phase showed 24 (38%) IADSAs were superior to film study and all were satisfactory for the diagnostic purposes. Ninety-eight percent of 86 IADSPs gave information about the patency of the main portal vein. Fifty-five percent of IADSPs opacified third-order portal vein branches or further. IADSA of hepatic tumors not only save time and contrast dose but was also satisfactory in image quality for interventional angiography.
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CT and angiographic features of nine incidentally discovered small renal adenocarcinomas are reviewed. They were all discovered by CT or US during screening procedures or examinations targeting the liver or pancreas. In our institute, they constituted 56 percent of renal adenocarcinomas whose diameters were 4 cm or less. CT without contrast enhancement detected abnormality in seven of the nine, but two were negative or equivocal. Postcontrast CT delineated all tumors as relatively low-density areas, since the normal parenchyma of the kidney showed intense contrast enhancement. We believe that isodense or nearly isodense masses that show relatively low density after contrast are diagnostic of small solid renal tumors. Dynamic study with a bolus injection of contrast medium added information about the vascularity of the tumors. Angiography revealed hypervascularity in only four of the tumors. The rest were avascular or hypovascular. Four tumors that were avascular in the AP arteriographic view were shown to be hypovascular by a tailored oblique view in which adequate obliquity of the angiographic projection was determined by referring to CT, so that the tumors would be seen in profile and would not be superimposed on by normal parenchyma or vertebral shadows.
Early experience in magnetic resonance (MR) images of the liver tumors is reported, based on 25 cases examined by a 0.35T superconducting machine (Magnetom, Siemens) using the spin echo technique. All main liver tumors were demonstrated as high intensity areas of varying degree in the spin echo image with a TR of 1,600 msec and a TE of 70 msec. All of them had prolonged T2 and T1. The smallest lesion detected on MR was 0.8 cm in diameter in the cases of multiple liver cysts and 1.5 cm in the cases of a solitary solid tumor. Normal vasculature of the liver was well-delineated, despite a far longer acquisition time compared with respiratory holding period. MR is a promising modality for liver imaging.
We report an unusual case of multilocular cystic hepatocellular carcinoma. The patient was a 42-year-old woman without liver cirrhosis but who had three multicystic mass lesions in the liver. Transcatheter arterial embolization was very effective and a survival time of more than 19 months was obtained.
Intraarterial digital subtraction portography (IADSP) via the superior mesenteric artery was performed in 50 patients with liver tumors. In most cases IADSPs provided images as good as conventional arterial portography through the superior mesenteric artery and they produced important information as to whether patients should be treated by transcatheter arterial embolization, surgical resection or chemotherapy. IADSP helps to reduce the examination time, the number of films and contrast material used, as well as the pain suffered by patients.
Intraarterial digital subtraction angiography (IADSA) of peripheral arteries with isotonic contrast material, which was prepared by diluting meglumine amidotrizoate (65% Angiografin), was performed in ten patients. In six, both IADSA and conventional screen-film arteriography were performed for comparison. Painless peripheral arteriography was achieved by IADSA with isotonic contrast material. Five IADSAs were safely done on an outpatient basis. Visualization of arteries by IADSA was satisfactory, but the details of smaller arteries were better shown by screen-film arteriography. Visualization of faint stains was better in IADSA. The authors believe that IADSA with isotonic contrast material is a method of choice for the diagnosis of vascular diseases and tumorous conditions of extremities, as well as for the purpose of preoperative vascular mapping. It is safely performed with smaller dose of contrast material on outpatient basis, and with less discomfort and cost for the patient.
Sclerosing hepatic carcinoma (SHC) is one of the variant primary liver carcinomas and is characterized by intense fibrosis which surrounds slender cords of neoplastic cells. We report on a 53-year-old male patient with SHC describing the radiological findings and clinical course after a transcatheter arterial embolization. To our knowledge, this was only the second reported case of SHC in Japan.
Chondroitin sulfate iron colloid (CSIC) is a therapeutic agent for iron deficiency anemia. The potential of CSIC to decrease liver signal intensity at magnetic resonance (MR) imaging has already been tested. Enhanced detection of liver carcinoma by CSIC at MR imaging was studied in vivo. Our purpose was to determine the time period required to obtain the maximum contrast enhancement from CSIC at different dose levels. We performed MR imaging of eight rats with hepatic carcinoma before and after CSIC administration. For all dose groups it was found that on T2-weighted images the maximum contrast to noise ratio (C/N) was at 4-8 hours after the drug administration, while on proton density-weighted images the maximum C/N was at 2-8 hours.
To define the frequency of decreased signal intensity (DSI) in cerebral cortex on T2-weighted images relative to aging and to the incidence of identifying white matter pathology, T2-weighted MR brain images of 906 patients consecutively examined between July 1989 and June 1991 were reviewed. MR images of cerebral cortex were divided into five areas: frontal lobe (F), pre- and postcentral gyri (C), parietal lobe (P), occipital lobe (O) and temporal lobe (T). Each area was separately and independently evaluated for the presence or absence of DSI. The frequency of DSI in each area was plotted against patients' ages. The severity of leukoaraiosis was evaluated in relation with DSI in each cortical area. Patients with DSI in area F numbered 61 (5.7%), in area C 236 (26.0%), in area P 174 (15.9%), in area O 428 (47.2%), and in area T 10 (1.1%). The number of patients with DSI in each area increased with age. The greater the severity of leukoaraiosis, the greater the chance of finding DSI of the cerebral cortex. The incidence of DSI in the cerebral cortex increased with the patient's age as well as with the severity of co-existent white matter pathology.
We report the imaging and pathological findings of a rare case of intraosseous ganglion communicating with extraosseous counterpart. Both counterparts contain air and show rim-enhancement on T1-weighted images. Histopathologically, the enhanced-rim consists of reactive proliferation of capillary vessels due to degeneration.
The purpose of this study was to compare Turbo-FLAIR imaging, T2-weighted imaging, and double-dose gadolinium-enhanced MR imaging in the detection of brain metastasis. Using the three sequences, 20 consecutive patients with brain metastases were prospectively studied with a 1.5-Tesla system. Three independent, blinded readers assessed the images for the presence, size, number, and location of metastatic lesions. In the detection of large lesions (> 0.5 cm), Turbo-FLAIR imaging (38/48, 79%) was not significantly different from gadolinium-enhanced imaging (42/48, 88%) (p = 0.273). T2-weighted imaging (31/48, 65%), however, was inferior to gadolinium-enhanced imaging (p < 0.05). There was no difference between Turbo-FLAIR imaging and gadolinium-enhanced imaging in the accuracy of detecting solitary brain metastasis (4/4, 100%). In conclusion, Turbo-FLAIR imaging is a useful, noninvasive screening modality for brain metastasis. Its use may lead to cost savings in the diagnosis of brain metastases and may impact positively the cost-effectiveness of treatment.