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Biomedical subjects

I Isomoto

Publications and source records attributed to I Isomoto.

At least 19 recordsLinked to original sources
PubMed2001

Successful treatment of bleeding due to ileal varices in a patient with hepatocellular carcinoma.

This case report concerns a 62-year-old female who was known to have cirrhosis. An endoscopic examination showed no evidence of haemorrhaging due to either oesophageal or gastric varices. Angiographic studies demonstrated extravasation from the ileal varices. There was a prominent arterio-portal shunt in the liver, and the shunt was considered to be a contributing factor to induce portal hypertension and variceal bleeding in the ileum. Therefore, transcatheter arterial embolization was performed, but was unsuccessful. As a result, the patient underwent a laparotomy, and a dilatating ileocaecal vein and a communicating ovarian vein were selectively ligated. Following the procedure, the haemorrhaging stopped and she then recovered. The patient is doing well 21 months after surgery at the time of writing.

Carcinoma, Hepatocellular↗
PubMed2001

Unenhanced CT findings of vascular compromise in association with intussusceptions in adults.

OBJECTIVE: The purpose of this study was to evaluate unenhanced CT findings for predicting the degree of vascular compromise in intussusception observed at surgery. MATERIALS AND METHODS: The imaging studies, clinical records, and surgical and pathologic findings in 25 patients with intussusception were reviewed retrospectively. We evaluated six CT findings based on the abnormalities of each component of intussusception. Presence or absence of these findings was compared with the degree of vascular compromise as observed on pathologic examination, such as edema, ischemia, or necrosis. RESULTS: The hypodense layer was observed in 16 of 18 intussusceptions with various degrees of vascular compromise. A fluid collection surrounded by the returning wall, which was revealed to correspond to trapped peritoneal fluid, was observed in eight of nine intussusceptions with ischemia or necrosis. A gas collection surrounded by the returning wall was observed in two of four intussusceptions with necrosis. Free peritoneal fluid coexisted with a fluid collection surrounded by the returning wall in all the intussusceptions except one. Bowel obstruction was observed in six of nine intussusceptions with ischemia or necrosis. The maximum wall thickness was not related to the degree of vascular compromise. CONCLUSION: The CT findings of a hypodense layer in the returning wall, fluid collection in the space surrounded by the returning wall, and gas collection in the space surrounded by the returning wall can be useful in predicting the degree of vascular compromise in intussusception.

Adolescent↗
PubMed2000

Evaluation of aberrant bile ducts before laparoscopic cholecystectomy: helical CT cholangiography versus MR cholangiography.

OBJECTIVE: The purpose of our study was to compare the accuracy of helical CT cholangiography and that of MR cholangiography in the diagnosis of aberrant bile ducts or cystic ducts before laparoscopic cholecystectomy. SUBJECTS AND METHODS: A total of 120 consecutive patients, including 114 patients with cholecystolithiasis and six with gallbladder polyps, were treated using laparoscopic cholecystectomy between November 1996 and August 1998. Eighteen (15%) of the 120 patients were suspected of having aberrant bile ducts or cystic ducts on helical CT cholangiography, and 16 of these 18 patients were subsequently examined on MR cholangiography. For the 16 patients who underwent both imaging examinations, findings from helical CT cholangiography and MR cholangiography were compared with intraoperative cholangiography. RESULTS: Aberrant bile ducts in 13 patients and aberrant cystic ducts in three patients were divided into six types on the basis of the results of intraoperative cholangiography. Although these types were clearly identified using helical CT cholangiography in all 16 patients, the anatomic variants were not correctly identified in seven (44%) of the 16 patients with MR cholangiography. False-negative findings were mainly a result of the insertion sites of the cystic ducts or aberrant bile ducts being obscured by aberrant bile ducts or duodenum. Two (2%) of the 120 patients developed mild adverse reactions to the contrast material, but neither required treatment. CONCLUSION: Helical CT cholangiography clearly showed aberrant bile ducts and cystic ducts, but visualization of these structures on MR cholangiography was unsatisfactory because of overlapping duodenum and hepatic ducts.

Adult↗
PubMed2000

[Gradually enhancing breast cancer on dynamic MRI].

PURPOSE: The aim of our study was to evaluate the frequency and the radiologic and pathologic features of gradually enhancing breast cancers on contrast enhanced dynamic MRI. MATERIAL AND METHODS: 83 patients with pathologically proven breast cancer underwent contrast enhanced dynamic MRI. Breast cancers that showed a gradually enhancing pattern were selected, and their pathological features and the findings in other imaging modalities were retrospectively analyzed. RESULTS: Of 83 lesions, 8 lesions (10%) showed a gradually enhancing pattern on dynamic MRI. The lesions included 3 papillotubular carcinomas, 3 scirrhous carcinomas, one solid-tubular carcinoma, and one mucinous carcinoma. All of them had imaging features suggesting malignancy on mammography and ultrasonography. Histopathologically, all 7 invasive ductal carcinomas showed prominent fibrosis in the stroma, and one showed many dilated ducts. One mucinous carcinoma showed large mucinous pools. CONCLUSION: Some breast cancers may show a gradually enhancing pattern on dynamic MRI. Other imaging features should be taken into account in the differential diagnosis of breast tumors.

Adult↗
PubMed1998

Granular Cell Tumor of the Breast: A Case Report Describing Dynamic MR Mammography.

A case of granular cell tumor of the breast in a 36-year-old woman is reported. The patient presented with a hard mass,1.5 cm in diameter in the upper-outer quadrant of the left breast. Physical examination and ultrasonography suggested the presence of breast carcinoma. An aspiration biopsy cytology(ABC)specimen wasevaluated as class II, and dynamic magnetic resonance(MR)mammography indicated a benign tumor. Granular cell tumor was finally diagnosed on examination of an excisional biopsy specimen. Granular cell tumor of the breast can mimic breast carcinoma on physical examination, mammography, ultrasonography, and even gross inspection. Dynamic MR mammography has the potential distinguish this condition from carcinoma. Awareness of this disease and prudent use of diagnostic procedures, including MR mammography, will help prevent misdiagnosis and unnecessary surgery.

Journal Article↗
PubMed1998

[Differentiation between benign and malignant breast lesions using fat-suppressed dynamic MR imaging].

PURPOSE: To assess the value and problems of fat-suppressed dynamic MR imaging in differentiating between benign and malignant lesions. MATERIALS AND METHODS: In twenty-nine patients who underwent excisional biopsy or surgical resection, fat-suppressed dynamic MR imaging was performed with a 0.5 T superconducting magnet. Pre-and postcontrast 3D-spoiled gradient echo sequences were employed with fat suppression. We calculated and evaluated the contrast-to-noise ratio (CNR) and contrast enhancement ratio (CER) at each contrast determination time (CDT), which is the intermediate time in the scan. RESULTS: Time intensity curves of CNR showed no statistically significant difference between cancers and other benign lesions. The difference in CER between malignant and benign disease was highly significant (P = .006) at CDT 45 sec., but there was great overlap in the time intensity curve of CER after CDT 45 sec. CONCLUSION: When we attempt to differentiate malignant from benign breast lesions by dynamic MR imaging, comparison of CNR is impertinent, and we should evaluate the differential diagnosis of cancer versus benign lesions by means of CER at CDT points of about 45 sec.

Adolescent↗
PubMed1998

[Diagnosis of common bile duct stones by MR imaging, mainly MR cholangiopancreatography].

We evaluated the accuracy of MR imaging (MRI), mainly MR cholangiopancreatography (MRCP), in the diagnosis of choledocholithiasis in comparison with ultrasound (US), computed tomography (CT), direct cholangiography, and intravenous cholangiography (DIC). Thirty-seven patients with biliary disease diagnosed by surgery and direct cholangiography underwent MRI with T1-weighted images (T1-WI), T2-weighted images (T2-WI), and MRCP (source images and projection images). The rate of stone detection was evaluated for each MRI image and modality. Fifteen of 37 patients were found to have common bile duct stones at surgery. The depiction rate of T1-WI, T2-WI, source images, and projection images were 7%, 67%, 93%, and 53%, respectively. The depiction rate of MR, US, CT, direct cholangiography, and DIC were 100% (15/15), 25% (3/12), 64% (9/14), 71% (5/7), and 57% (4/7), respectively. In addition, there were two false-positive cases, one of duodenal diverticulum (Lemmel's syndrome) and the other of hemobilia. MRI had a sensitivity of 100%, specificity of 91%, and accuracy of 94% in the diagnosis of common bile duct stones. In conclusion, MRI is useful for evaluating suspected choledocholithiasis. In spite of the high depiction rate of the source images, other images should also be taken into consideration in the diagnosis of choledocholithiasis.

Adult↗
PubMed1997

[Efficacy of respiratory-triggered fast spin-echo 3 dimensional-MR cholangiopancreatography on middle magnetic field MR imaging].

We compared the image quality of three-dimensional (3D) MR cholangiopancreatography (MRCP) and two-dimensional (2D) MRCP on middle magnetic field MR imaging, using a respiratory-triggered fast spin-echo technique in 10 volunteers and 69 patients suspected of having biliary and pancreatic diseases. The bile ducts (BDs) and main pancreatic ducts (MPDs) are, if dilatated, are almost always depicted by 3D-MRCP and 2D-MRCP. The depiction rates by 3D-MRCP of non-dilatated intrahepatic ducts (IHDs), hepatic ducts (HDs), common hepatic ducts, common BDs, cystic ducts (CDs) and MPDs were 57%, 90%, 95%, 95%, 100% and 77%, respectively. The respective rates for 2D-MRCP were 26%, 95%, 100%, 95%, 74% and 38%. Non-dilatated IHDs, CDs, and MPDs were better visualized on 3D-MRCP than on 2D-MRCP, because of the high contrast to-noise ratio and high spatial resolution in the slice-section direction of 3D-MRCP. In conclusion, respiratory triggered fast spin-echo 3D-MRCP on middle magnetic field MR imaging is useful in the evaluation of biliary and pancreatic diseases.

Adult↗
PubMed1996

[Efficacy of respiratory-triggered fast spin echo MR cholangiopancreatography on intermediate MR imaging].

MR cholangiopancreatography (MRCP) using a respiratory-triggered fast spin-echo technique was performed on intermediate MR imaging in 26 patients with suspected biliary disease. In almost all of 12 patients without dilated biliary tract, the hilum of the liver and extrahepatic bile duct were clearly visualized. All of 11 cases of cholelithiasis were demonstrated. In all 4 cases of obstructive jaundice, dilatation and obstruction of the bile ducts were clearly demonstrated. Respiratory-triggered fast spin-echo MRCP is a non-invasive technique for visualization of the biliary tract and biliary disease on intermediate MR imaging.

Bile Ducts↗
PubMed1994

Multiple intrahepatic aneurysms following transcatheter arterial embolization. Work in progress.

PURPOSE: To discuss the mechanism of multiple intrahepatic aneurysm formation after transcatheter arterial embolization (TAE) performed in five patients with hepatocellular carcinoma. MATERIALS AND METHODS: TAE was performed with gelatin sponge particles and iodized oil as embolic materials. Mitomycin C was also used in four cases. RESULTS: Three to 14 aneurysms 1-6 mm in diameter were found in third-to sixth-order branches of the hepatic arteries at repeat angiography performed 25-45 days after TAE. Follow-up angiograms in three cases revealed that most aneurysms were no longer apparent except in one patient in whom two aneurysms remained and were larger than before. In none of the five cases were any signs of aneurysm rupture noted. CONCLUSION: Radiologists should be aware of this complication of TAE. It is speculated that the main cause of aneurysm formation in these patients was the embolic agents used.

Aneurysm↗
PubMed1994

Locked-in syndrome and abnormal orientation of the right vertebral artery in a young man.

A 35-year-old man developed a cerebral infarction and experienced transient ischemic attacks originating from the vertebrobasilar artery, as well as locked-in syndrome. He recovered with minimal neurological deficit. On cerebral angiography, the orientation of the right vertebral artery was markedly abnormal as it entered the foramina of the transverse process at the level of the third cervical vertebra. We concluded that the abnormal orientation of the vertebral artery caused the thrombosis and that the transient ischemic attacks, locked-in syndrome and cerebral infarction were brought about by thromboemboli originating in this artery.

Adult↗
PubMed1993

[CT findings of invaginated mesentery in adult intussusception].

The CT findings of invaginated mesentery in adult intussusception were analyzed in 12 patients (three patients with four small bowel intussusceptions and nine patients with nine large bowel intussusceptions). In all small bowel intussusceptions, the neck was located near the superior mesenteric artery and vein (SMA & SMV) and showed a medial opening, and the vessels in the neck showed a continuity to the left side of SMA & SMV. In most of the large bowel intussusceptions, the neck was located distant from SMA & SMV, and the vessels in the neck did not show continuity to SMA & SMV. The difference in CT findings between small and large bowel intussusception is attributed to the difference in mesenteric anatomy; the small bowel and its mesentery move freely in the peritoneal cavity, whereas the large bowel is partially fixed to the retroperitoneum.

Adult↗
PubMed1992

[Reevaluation of US and CT findings in adult intussusception].

Computed tomographic (CT) and ultrasonographic (US) findings of 10 adult patients with 11 intussusceptions were retrospectively analyzed. Through close scrutiny of wall structures of intussusceptums and mesenteric fat, new features of adult intussusceptions were found: 1. The returning walls were thicker than the entering walls in 10 of 11 intussusceptums. 2. The neck of the returning wall was thicker than its head in eight of nine intussusceptums. 3. Longitudinal compression of the wall and venous congestion resulting from an inside out turning of the wall structure were thought to be the cause of thickening of the returning wall. 4. Invaginated mesenteric fat tended to be located at the head (apex) in two of seven intussusceptions, making differentiation from intussusception caused by lipoma difficult. 5. The leading masses were detectable as apical soft tissue density masses in eight of 10 intussusceptions. These findings contradict those of previous reports on adult intussusceptions.

Adult↗
PubMed1991

[Radiologic manifestations of peritoneal mesothelioma].

We report four cases of histologically proved peritoneal mesothelioma and describe the radiographic (mainly CT and angiographic) findings. There were three malignant diffuse tumors and one benign localized tumor. In one case, the lesion extended to the omentum and entrapped the fat tissue, and differentiation from peritonitis carcinomatosa was difficult. In the other three cases, reflecting necrotic change within the tumor, CT showed hypodensity throughout most of the mass. In two cases with hemorrhage, CT showed hyperdensity in the center of the mass. Angiography showed slight or medium neovascularity in the periphery of the tumor, but most of the tumor was avascular. Angiography was helpful for topographic diagnosis, but it was difficult to make a specific diagnosis or differentiate between malignant and benign types. We emphasize that it is important to consider peritoneal mesothelioma in the differential diagnosis when a mass of unknown origin is found in the abdomen, particularly when it is accompanied by necrosis and hemorrhage.

Aged↗
PubMed1991

[Bile lake: a complication of transcatheter hepatic arterial infusion and embolization therapy (TAI, TAE)].

A 74-year-old man with hepatocellular carcinoma developed cholangitis and bile lake in the liver after repeated TAI (anticancer drug-lipiodol suspension) and gelfoam TAE. Despite percutaneous transhepatic drainage, he died of hepatic failure 34 months after the first TAI and TAE. We speculate that cholangitis and bile lake were caused by chemical toxicity of highly concentrated anticancer drug to the bile duct and compression of the proximal bile duct by the tumor.

Aged↗
PubMed1990

[CT and sonographic diagnosis of retained surgical sponge].

Seven cases of pathologically proven retained surgical sponge were reviewed and classified into four types, depending on CT and US findings. Type I: CT shows a mass with tiny gas bubbles, and sonogram shows an echogenic area with strong posterior shadow. Type II: CT shows an irregular high density mass with no gas bubble, and sonogram shows an echogenic area with strong posterior shadow. Type III: CT shows a low density mass with irregular internal high density areas, and sonogram shows a cystic mass with zigzag internal components. Type IV: CT shows an elliptic high density mass with low density area internally. Judging from the experiment and operative findings, these patterns were decided by the number and status of the gauze, volume of the exudate and hematoma, and status of the granulation. The author concludes that these characteristic CT and US findings, together with a history of surgery, permit the correct diagnosis of retained surgical sponge.

Adult↗