Biomedical subjects
Publications and source records attributed to M Kadoya.
We report a case of segmental hepatic iron deposition in the parenchyma peripheral to a tumor-thrombosed intrahepatic portal vein. On MR imaging, especially fast low-angle shot image, the liver parenchyma was demonstrated as a hypointense area with segmental and wedge-shaped configuration. Absence of portal blood flow may cause such segmental hepatic iron deposition.
We report a histological analysis of the areas of high density in the postequilibrium and delayed phase CT in 43 focal hepatic lesions. The cases consisted of 16 cholangiocellular carcinomas, 9 hepatocellular carcinomas (including a sclerosing type of hepatocellular carcinoma and a combined hepatocellular-cholangiocellular carcinoma), 13 metastases, 2 granulomas, an inflammatory pseudotumor, a malignant lymphoma, and an epithelioid hemangioendothelioma. Computed tomography was performed after hepatic angiography using 40-50 g iodine and arteriographic CT using 35 g iodine. The areas of delayed enhancement corresponded histologically to fibrotic tissues, from inflammatory change to extensive fibrosis.
OBJECTIVE: The enhancement of ascites following intravenous administration of Gd-DTPA on MRI was investigated. MATERIALS AND METHODS: Magnetic resonance imaging was performed in 20 patients with ascites (8 peritoneal carcinomatosis, 2 tuberculous peritonitis, 8 liver cirrhosis, 1 nephrotic syndrome, 1 peritoneal adhesion), and T1-weighted SE images were obtained before and 15-20 min following intravenous administration of Gd-DTPA (0.1 mmol/kg). RESULTS: There were 10 exudative ascites and 10 transudative ascites. Eight of 10 exudative ascites showed enhancement, in contrast to none of 10 transudative ascites. The precontrast signal intensity ratios (SIRs) of exudative ascites were significantly higher (p < 0.05) than those of transudative ascites, and the postcontrast SIRs of exudative ascites were significantly higher (p < 0.01) than those of transudative ascites. This difference was thought to be caused by increased peritoneal permeability and higher protein concentration in the cases with exudative ascites in this study. CONCLUSION: It is concluded that enhancement of ascites on MRI obtained 15-20 min after intravenous administration of Gd-DTPA is not an uncommon finding in exudative ascites (especially associated with peritoneal carcinomatosis).
OBJECTIVE: We report the imaging features of hepatic peribiliary cysts (PC) and the course of their development on CT. MATERIALS AND METHODS: Both CT and US findings were correlated with histopathologic findings in two patients with PC at autopsy. Five patients with cysts around the portal vein on CT but without histologic correlation were also included in this study. In six patients the course of PC development was observed. RESULTS: In the two autopsy cases cystic dilatation of the peribiliary glands was confirmed. The cases showed continuous small cysts along the portal veins reflecting the periportal collar seen on CT and the abnormal MR signal intensity of the periportal area. Ultrasound (US) showed round or tubular anechoic lesions around the large portal tracts mimicking dilatation of the bile ducts. Clustered cysts and echogenic dots or bands around PC were also seen. In three of six cases the PCs gradually enlarged and increased in number. CONCLUSION: In patients with liver cirrhosis PCs can be demonstrated by CT, US, and MRI in the vicinity of the hepatic hilum. Peribiliary cysts enlarge gradually and must be differentiated from dilatation of bile ducts or edema of portal tracts.
OBJECTIVE: The purpose of this study is to demonstrate the relation between focal hepatic fatty infiltration and aberrant gastric venous drainage (AGVD) in the posterior edge of the medial segment (PEMS) of the liver. MATERIALS AND METHODS: We present two cases of focal hepatic fatty infiltration with AGVD in the PEMS and discuss their imaging features. RESULTS: In both cases the focal fatty infiltration areas were hyperechoic on sonography, hypodense on CT, and hyperintense on T1-weighted MRI. Computed tomography during arterial portography (CTAP) showed nodular perfusion defects corresponding to the areas in both cases, and early enhancement of the area was observed with dynamic MRI in one case. Although the findings on CTAP and dynamic MRI suggested a neoplastic nature for the lesions, focal fatty infiltration was confirmed with surgical resection in one case and with imaging follow-up in the other. Aberrant gastric venous drainage into the area was demonstrated on arteriography in both cases. CONCLUSION: The variation in blood supply caused by AGVD may play an important role in fatty metabolism in the PEMS of the liver and may influence imaging features.
OBJECTIVE: To demonstrate the imaging findings seen in two cases of mucinous type of cholangiocellular carcinoma of the liver. MATERIALS AND METHODS: The CT and MR findings of two patients with pathologically proven mucinous type of cholangiocellular carcinoma were analyzed. RESULTS: One of them showed calcification, both cases had no enhancing on the arterial dominant phase of dynamic CT, but showed enhancement in the periphery and internal septations on the equilibrium phase. The internal signal intensity was homogenous, and extremely hypo- and hyperintense on T1- and T2-weighted images, respectively. CONCLUSION: Imaging findings were unique reflecting the characteristic pathological features that cancer cell nests are suspended in a large mucinous lake, and the specific diagnosis was considered to be possible by the integrated imaging diagnosis.
PURPOSE: The purpose of our study was to assess the efficacy of single-level dynamic CT during hepatic arteriography (D-CTA) in the differentiation between hypervascular hepatocellular carcinoma (HCC) and hypervascular pseudolesion. METHOD: D-CTA was performed in nine cases with HCC and nine cases with pseudolesion. Findings on D-CTA were retrospectively analyzed. RESULTS: The transition of the stain of pseudolesion on D-CTA was divided into three phases: (1) inflow of the contrast material into the portal vein within the lesion, (2) lesion staining, and (3) fading out of the stain; that of HCC was divided into four phases: (1) inflow of CM into tumor, (2) tumor staining, (3) inflow of CM into the adjacent liver, and (4) coronal stain of adjacent liver. The coronal stain was seen in all HCCs but not in any pseudolesions. CONCLUSION: The present study suggest that D-CTA is a helpful option in the differentiation between HCC and pseudolesion.
PURPOSE: The goal of our study was to assess the prevalence of pseudolesion in segment IV of the liver on MRI in patients with and without liver cirrhosis. METHOD: Patients were divided into three groups: 10 patients with angiographically confirmed aberrant gastric venous drainage and liver cirrhosis (Group 1), 250 consecutively selected patients with liver cirrhosis (Group 2), and 250 with normal liver (Group 3). The signal intensity of pseudolesion in segment IV on T1- and T2-weighted MRI in the 510 patients was analyzed. RESULTS: In Group 1, five pseudolesions were visible and hyperintense on T1-weighted images. On T2-weighted images, four were visible and hypointense. In Group 2, 11 were seen (4.4%). All were hyperintense on T1-weighted images. Five were hypointense on T2-weighted images. In Group 3, one pseudolesion was seen (0.4%). CONCLUSION: The prevalence of pseudolesion in segment IV on MRI is higher in liver cirrhosis than in normal liver. The lesion is hyperintense on T1-weighted images when visible.
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We report three cases of pseudolesions caused by aberrant right gastric venous drainage (AGVD) in segment II/III of the liver as demonstrated on CT during arterial portography (CTAP). On CTAP, the lesions were seen as wedge-shaped perfusion defects, and on hepatic arteriography, AGVD directed to the area with the perfusion defect was visible in all three cases. When a perfusion defect is detected at the edge of segments II/III at CTAP, a pseudolesion caused by AGVD should be suspected.
We studied the electrophysiological effects of amiodarone on isolated rabbit heart muscles by conventional microelectrode techniques. It significantly suppressed not only sinus node functions (basic cycle length, sinus recovery time, and corrected sinus recovery time) but also atrioventricular node functions (AH interval, effective refractory period, and functional refractory period) by both superfusion (10 micrograms/ml amiodarone in Tyrode solution) and long-term oral administration (50 mg/day for 2 weeks, then 25 mg/day for 4-6 weeks). On the other hand, oral administration significantly lengthened the action potential duration and effective refractory period of the left atrium and the right ventricle, while superfusion did not. The maximum rate of depolarization, action potential amplitude, and diastolic resting potential were not changed by either route of administration. It is thought that the action of amiodarone on the sinus node and on the atrioventricular node is mainly due to its noncompetitive sympathetic inhibition, and that its action on the left atrium and on the right ventricle is mainly due to reduction of serum triiodothyronine, which requires long-term administration of amiodarone.
We experienced a case of focal fatty infiltration in the anteromedial edge of the medial segment of the liver adjacent to the falciform ligament associated with advanced esophageal cancer. By using CT during selective right internal thoracic arteriography, we confirmed that the inferior vein of Sappey drained into the area of focal fatty infiltration. This is the first case to directly establish the relationship between drainage of the inferior vein of Sappey and occurrence of focal fatty infiltration of the liver.
This report describes three patients whose cystic portions were filled with intravenously injected Gadolinium-DTPA. Four cystic portions showed contrast enhancement of the whole wall on early MR images and enhancement of the content on delayed MR images. Two cystic portions showed no enhancement of content. We speculate that the difference is based upon the composition of the cyst walls.
A total of 155 cases of hepatocellular carcinoma smaller than 3 cm in greatest diameter were studied, and the survival rates obtained with various treatment methods were calculated. Patients were divided into an operated group (72 cases), transcatheter arterial embolization (TAE) group (52 cases), percutaneous ethanol injection therapy (PEIT) group (five cases), and a miscellaneous group (26 cases) according to the treatment received. The miscellaneous group included intraarterial chemotherapy, systemic chemotherapy, and no therapy. The survival rates of the operated and TAE groups were significantly higher than those of the miscellaneous group, but the survival rates of the TAE group decreased after two years had passed, and TAE showed limited long-term survival. In the PEIT group, the survival rates after three years were higher than those of the TAE group. TAE is effective for inoperable small HCC, but the indications for PEIT should be considered actively.
Olfactory bulbs are easily detected on coronal T1-weighted MR images. They are situated almost symmetrically opposite either side of the lower end of the olfactory sulci, and, on sagittal images, they are observed as thin soft-tissue bands immediately beneath the frontal lobe base. On axial images they are shown as oval, paramedian structures of intermediate intensity. Visualization of the olfactory tract, however, is not always possible. Our study reveals that, on axial images, detection of the olfactory bulb depends on technical factors; we recommend a 256 x 256 matrix, a 3-mm-thick slice, and less than a 0.6-mm gap. Despite the lack of complete visualization of olfactory bulbs and tracts, MR may be effective in demonstrating diseases of these entities.
In this report, the relationship of acoustic neuromas to the adjacent cranial nerves is discussed. On T1-weighted images, the trigeminal nerve was detected in all 13 cases. Mild to marked compression of these nerves by the tumors was observed in eight cases. The extent of compression did not always correspond to the clinical symptoms. In four cases with a maximum tumor diameter of 2 cm or less, the 7th and 8th cranial nerves were identified. There was no facial palsy in these patients. Two patients with a tumor diameter of more than 2 cm also had no facial palsy. All patients, including those with small tumors, complained of hearing loss and/or tinnitus. While MR imaging has some limitations, it is an effective imaging modality for showing the relationship between tumors and nerves.
Computed tomography (CT) during arterial portography was performed in two cases of idiopathic portal hypertension (IPH). Multiple patchy low-density areas with unclear margins and abnormally short distances between some of the medium-sized portal branches and the liver surface were demonstrated. These findings were distinctly different from those of liver cirrhosis. CT during arterial portography was useful for differentiating IPH from liver cirrhosis.
Magnetic resonance imaging (MRI) was performed in ten patients with intracranial lymphoma. Seven were pathologically confirmed and three were clinically diagnosed. Nineteen lesions were found among the ten cases. None had acquired immunodeficiency syndrome (AIDS) or had received immunosuppression therapy. Two lesions were in the lateral and third ventricles, and the others were predominantly in the corpus callosum, deep white matter, or central gray matter. Four patients had multiple lesions. All had mild to severe edema. On T1-weighted images, all lesions showed hypointensity. On T2-weighted images, three lesions showed definite hypointensity to gray matter, and the others showed hyperintensity. The contour of all lesions was well demarcated from the surrounding edema. Eight cases were scanned before and after intravenous administration of 0.1 mmol/kg of gadolinium-dimethylene triaminepentaacetic acid (Gd-DTPA), and all exhibited homogeneous enhancement. Three cases showed blurred enhancement margins. Four cases showed hemorrhage, and the frequency of hemorrhage was higher than in previous reports. Pathological examination was performed in seven cases. All showed dense concentric lymphoma cells without necrosis. There was no pathological difference between the hyperintense and hypointense lesions on T2-weighted images.