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Biomedical subjects

O Matsui

Publications and source records attributed to O Matsui.

At least 37 records · Page 2Linked to original sources
PubMed2001

Improved cerebral perfusion and metabolism after stenting for basilar artery stenosis: technical case report.

OBJECTIVE: Recent advances in stent technology have allowed the introduction of more flexible stents that may be tracked more easily in the intracranial vessels. We present a patient with improved cerebral blood flow and metabolism as assessed by positron emission tomography after stent-assisted angioplasty for symptomatic basilar artery stenosis. CLINICAL PRESENTATION: A 62-year-old man, who had undergone left superficial temporal artery to middle cerebral artery bypass surgery for left internal carotid artery occlusion 10 years previously, presented with dizziness, blurred vision, and memory disturbance. Angiography revealed severe stenosis of the proximal basilar artery. Positron emission tomographic scans revealed decreased cerebral blood flow associated with increased oxygen extraction fraction in the entire brain, particularly in the posterior circulation and the left middle cerebral artery territory. Despite medical treatment, the patient experienced worsening visual disturbance and right-sided motor weakness. INTERVENTION: Ticlopidine and aspirin were used as antiplatelet agents. In addition, we used argatroban, which is a direct thrombin inhibitor, as an anticoagulant during the procedure. Predilation with a coronary artery balloon was performed, followed by placement of a GFX 3- by 8-mm stent (Arterial Vascular Engineering, Santa Rosa, CA), with excellent angiographic results. The patient made a good neurological recovery, and the postoperative positron emission tomographic scan demonstrated increases in both cerebral blood flow and cerebral metabolic rate of oxygen with a normalization of oxygen extraction fraction. CONCLUSION: Stent-assisted angioplasty can provide a favorable clinical course as well as improved cerebral perfusion and metabolism for a patient with basilar artery stenosis. Long-term follow-up data and additional clinical experience are required to assess the durability of this approach.

Brain↗
PubMed2001

Thymic lesions in patients with myasthenia gravis: characterization with thallium 201 scintigraphy.

PURPOSE: To assess thallium 201 ((201)Tl) single photon emission computed tomography (SPECT) for evaluation of thymic lesions associated with myasthenia gravis (MG), including lymphoid follicular hyperplasia (LFH) and thymoma. MATERIALS AND METHODS: (201)Tl SPECT and computed tomography (CT) were performed preoperatively in 46 patients with MG who had undergone thymectomy. SPECT was conducted 15 (early image) and 180 (delayed image) minutes after (201)Tl injection. Results were visually assessed, and (201)Tl uptake ratios (thymic lesion count density/lung count density) were measured for quantitative analysis. Uptake was analyzed among the normal thymus, LFH, and thymoma patient groups. RESULTS: Histopathologic results indicated a normal thymus, LFH, and thymoma in 19, 16, and 11 patients, respectively. Mean uptake ratios in the normal thymus, LFH, and thymoma were 0.96 (95% CI: 0.90, 1.03), 1.14 (95% CI: 1.04, 1.25), and 1.87 (95% CI: 1.56, 2.25), respectively, on early images and 1.09 (95% CI: 1.00, 1.18), 1.65 (95% CI: 1.48, 1.85), and 2.03 (95% CI: 1.65, 2.50), respectively, on delayed images. Thymoma showed more intense (201)Tl accumulation than did the normal thymus (P <.001) and LFH (P <.001) on early images. Both thymoma (P <.001) and LFH (P <.001) displayed more intense uptake than did the normal thymus on delayed images. CONCLUSION: (201)Tl SPECT can enable differentiation between normal thymus, LFH, and thymoma in patients with MG.

Adult↗
PubMed2001

Pseudolesion in segment IV of the liver adjacent to the falciform ligament caused by drainage of the paraumbilical vein: demonstration by power Doppler ultrasound.

A case of a pseudolesion in segment IV of the liver, adjacent to the falciform ligament, was observed on conventional CT and CT during arterial portography. The pseudolesion was caused by drainage of the paraumbilical vein. Power Doppler ultrasound was helpful in recognizing this pseudolesion by depicting that the paraumbilical vein was connected to vessels in this area. Although the direction of flow could not be determined, power Doppler ultrasound is a useful method for confirming non-invasively the aetiology of pseudolesions in this area.

Adult↗
PubMed2001

Myxedema accompanied by huge portal-systemic shunt without portal hypertension.

A 43-year-old woman with a huge portal-systemic shunt accompanied by myxedema showed slow speech and behavior. Several imaging studies revealed a bold portal-systemic shunt from the splenic vein to the left renal vein. In addition, hypothyroidism caused by chronic thyroiditis was diagnosed, and synthesized thyroxine replacement was effective for the symptoms. However, the serum ammonia and indocyanin green retention remained in the abnormal range, nevertheless the portal vein pressure was normal and findings of liver cirrohsis were not recognized histologically. Surgical shunt closure was performed, resulting in normalized serum ammonia levels and serum branched chain amino acids /aromatic amino acids ratio, and improvement of the ammonia tolerance test.

Adult↗
PubMed2001

Dynamic CT of hepatic abscesses: significance of transient segmental enhancement.

OBJECTIVE: The purpose of this study was to evaluate dynamic CT findings of hepatic abscesses, especially segmental hepatic enhancement, and to clarify the cause. MATERIALS AND METHODS: Twenty-four abscesses in eight patients were examined by early (30 sec) and late phase (90 sec) dynamic CT. Patients underwent abscess drainage (n = 1), hepatic resection (n = 2), or antibiotic therapy (n = 5). CT during arterial portography and CT during hepatic arteriography were performed in one patient. We retrospectively observed the frequency and changes of segmental hepatic enhancement on dynamic CT and determined its cause using radiologic and pathologic correlation. RESULTS: Sixteen abscesses (67%) showed transient segmental hepatic enhancement and three abscesses showed only segmental hepatic enhancement in the early phase. Four abscesses in one patient who underwent CT during arterial portography and CT during hepatic arteriography showed a segmental perfusion defect on CT during arterial portography and segmental enhancement on CT during hepatic arteriography. On follow-up dynamic CT performed 10-17 days after the initial CT, segmental hepatic enhancement surrounding hepatic abscesses decreased or disappeared in all abscesses. Pathologic examination of two patients showed marked inflammatory cell infiltration with stenosis of portal venules within the portal tracts surrounding hepatic abscesses without definite inflammation in the liver parenchyma. CONCLUSION: Segmental hepatic enhancement on dynamic CT is frequently associated with hepatic abscesses and may be caused by decreased portal flow resulting from inflammation of the portal tracts.

Aged↗
PubMed2001

[Angio CT].

Explore the source record for details and available documents.

Angiography↗
PubMed2000

Breast cancer in dense breast: detection with contrast-enhanced dynamic MR imaging.

The purpose of this study was to identify contrast enhancement patterns of dense breast parenchyma and to investigate the ability of dynamic magnetic resonance imaging (MRI) to detect cancer in the dense breast. Thirty-two patients with breast cancer in dense breast underwent gadolinium-enhanced dynamic MRI. The detectability of cancer by dynamic MRI, mammography, and physical examination was compared. Two parenchymal enhancement patterns could be identified. One was increasingly multiple patchy enhancement found predominantly in the periphery (type A), and the other was faint enhancement without any nodular opacification (type B). Type A was thought to reflect severe proliferative fibrocystic change (PFC). For both patterns, the detection rate of primary cancers by dynamic MRI was found to be superior to that by other modalities. Dynamic MRI also could detect multifocal cancers, which could not be found with other modalities, although the detectability of these small cancers might be reduced in patients with severe PFC.

Adenocarcinoma↗
PubMed2000

Cerebellar hemorrhage after coil embolization for a ruptured vertebral dissecting aneurysm.

BACKGROUND: We present a case of ruptured vertebral dissecting aneurysm that exhibited cerebellar hemorrhage after successful embolization of the vertebral artery including the dissected site. CASE PRESENTATION: A 59-year-old man suffered a sudden onset of severe occipital headache when he looked up. Computed tomography demonstrated subarachnoid hemorrhage. Angiography revealed a right vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery. Endovascular embolization of the aneurysm was performed with preservation of the posterior inferior cerebellar artery. The next day, the patient suffered a cerebellar hemorrhage in the vermis. The intracranial pressure was controlled by external ventricular drainage. The patient was discharged with mild cerebellar ataxia and bilateral abducens nerve palsy. CONCLUSION: In a case of vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery, blood circulation in the vertebral arterial system may change after embolization of the aneurysm. In our case, the preserved posterior inferior cerebellar artery might have been hemodynamically stressed postoperatively, resulting in cerebellar hemorrhage. Therefore, strict control of blood pressure is essential in the acute stage after occlusion of the aneurysm.

Aneurysm, Ruptured↗
PubMed2000

Evidence of the participation of peribiliary mast cells in regulation of the peribiliary vascular plexus along the intrahepatic biliary tree.

Our pilot study disclosed that tryptase-positive mast cells (MC) were densely distributed around the intrahepatic bile ducts (peribiliary MC). In this study, the pathophysiologic roles of these MC were examined with respect to the microcirculation around the bile duct in 71 cases of histologically normal liver, 24 cases of chronic hepatitis, and 45 cases of liver cirrhosis. The tryptase-positive MC were very close to the microvessels of the peribiliary vascular plexus (PVP), which supply the intrahepatic biliary tree. The tryptase-positive MC were frequently found adjacent to vascular smooth muscle cells, including pericytes. The location of the tryptase-positive MC was confirmed by ultrastructural analysis. In cirrhosis, the numbers of both microvessels of PVP and peribiliary MC increased in parallel. Peribiliary MC were immunoreactive for endothelin 1 (ET-1), and were variably immunoreactive for histamine, chymase, inducible nitric oxide synthase (iNOS), and endothelin A and B (ET(A) and ET(B)) receptors, particularly in cirrhotic livers. On vascular endothelial cells of PVP, endothelial nitric oxide synthase (eNOS) and ET-1 were consistently detectable, and ET(A) receptors, ET(B) receptors, and iNOS were variably detectable. Pericytes of PVP expressed ET(A) and ET(B) receptors in addition to ET-1 and iNOS. Biliary epithelial cells also focally expressed iNOS, ET-1, and ET(A) and ET(B) receptors. These vasoactive substances were strongly expressed on the cellular components in cirrhotic liver. By in situ hybridization, iNOS mRNA signals were observed on iNOS-immunoreactive cell components, including peribiliary MC. These morphologic and immunohistochemical findings suggest that the cellular components displaying vasoactive substances in the milieu of the intrahepatic biliary tree are very dynamic in the vasoregulation of PVP in normal livers, even more so in cirrhosis, and that peribiliary MC exert local effects on the microcirculation of PVP, directly and indirectly.

Bile Ducts, Intrahepatic↗
PubMed2000

Nonfunctioning islet cell carcinoma of the pancreas with high serum CEA & CA19-9, K-ras codon 12 mutation, and microsatellite instability.

A 55-year-old man with nonfunctioning islet cell carcinoma showing elevation of serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels is described with genetic analyses. Pathological examination of the resected specimen revealed two independent islet cell carcinomas, one in the body and the other in the tail of the pancreas. It was proved immunohistochemically that the tumor cells, particularly those in the tail, were immunoreactive to CEA and CA 19-9 and had the property of duct cells, as well as endocrine cells. Gastrin was demonstrated immunohistochemically in these tumor cells, although its level in serum was not elevated. Genetic analyses of the fresh specimens from the tumor in the body revealed K-ras codon 12 mutation and microsatellite instability. These findings are consistent with its progressive clinical course and strongly suggest that these tumors originate, not from the islet cells of Langerhans, but from protodifferentiated cells, capable of giving rise to all the pancreatic cell types.

Biomarkers↗
PubMed2000

Juxtaglomerular cell tumor of the kidney treated with nephron-sparing surgery.

A case of juxtaglomerular cell tumor of the right kidney is reported. A 30-year-old woman visited us with a complaint of headaches. Severe hypertension and an elevated level of plasma renin activity was seen at the initial evaluation. Computerized tomographic angiography revealed tumor vessels in the low-density mass in the right kidney. The preoperative diagnosis was renin-secreting tumor of the kidney, and nephron-sparing surgery was performed. The pathological findings showed a juxtaglomerular cell tumor. Postoperatively, prompt normalization of blood pressure and a reduced plasma renin activity level were observed.

Adenocarcinoma↗
PubMed2000

Hemodynamics of small hepatic focal nodular hyperplasia: evaluation with single-level dynamic CT during hepatic arteriography.

OBJECTIVE: We examined the usefulness of single-level dynamic CT during hepatic arteriography to observe the hemodynamics of small hepatic focal nodular hyperplasia. CONCLUSION: Single-level dynamic CT during hepatic arteriography revealed not only centrifugal blood supply through the fibrous stellate scar, but also the drainage to dilated veins in or near the focal nodular hyperplasia nodule and directly to the hepatic sinusoid in the surrounding liver.

Adult↗
PubMed2000

Malignant colonic obstruction due to extrinsic tumor: palliative treatment with a self-expanding nitinol stent.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of self-expanding nitinol stents for palliative treatment of malignant colorectal obstruction caused by unresectable extrinsic tumor, colorectal metastasis, or peritoneal seeding. SUBJECTS AND METHODS: One covered stent and 10 uncovered stents were deployed in eight patients with colorectal obstruction due to extrinsic tumor under fluoroscopic guidance. The sites of obstruction were located in the rectum (n = 5), in the rectosigmoid colon (n = 2), and from the transverse colon to the descending colon (n = 1). Clinical usefulness and complications were analyzed. RESULTS: Stents were placed successfully in all patients. Minor modifications of the delivery system were required in the tortuous rectosigmoid and lower rectum strictures. Symptoms of obstruction were initially resolved in all but one patient. In that patient, the presence of other points of obstruction was suspected. Bowel obstruction recurred in two patients: one obstruction was due to migration of a covered stent 4 days after the procedure, and the other obstruction was due to peritoneal seeding 33 days after the procedure. Both required colostomy or ileostomy. All patients died 12-111 days after stent placement (mean, 56 days). In five patients (63%), colonic obstruction was palliated by placing a stent until the patients' death between 39 and 111 days after stent placement (mean, 62 days). Six complications occurred in four patients and included stent migration (n = 1), anal bleeding (n = 2), anal pain that required analgesia (n = 1), and fever (n = 2). CONCLUSION; This self-expandable nitinol stent adequately palliated 63% of patients with colonic obstruction due to extrinsic tumor in this small series. Patient selection is very important to the success of this treatment.

Alloys↗
PubMed2000

Ruptured irregularly shaped aneurysms: pseudoaneurysm formation in a thrombus located at the rupture site.

OBJECT: The authors describe the clinical, radiological, and pathological findings of ruptured cerebral aneurysms with irregular configurations. METHODS: Eight patients with subarachnoid hemorrhage due to ruptured irregularly shaped aneurysms were examined. The preoperative radiological findings in these cases were compared with the pathological and operative findings of endovascular or open surgery. All of the aneurysms exhibited delayed opacification and delayed washout of contrast medium from the irregularly shaped portion of the aneurysm on digital subtraction angiography and/or helical computerized tomography scanning. Endovascular embolization with platinum coils was attempted in the first four patients who underwent treatment. In three of these patients the aneurysm ruptured again during the endovascular procedure. In the fourth patient an intraaneurysm thrombus was observed during the procedure and clipping was performed. In the subsequent four patients, three underwent clipping without complication and one underwent partial aneurysm embolization because of poor general status. A thrombus adjacent to the aneurysm dome was observed in the patients who underwent open surgery. Pathological examination of the operative specimens revealed a pseudoaneurysm-like cavity in the thrombus that was adherent to the aneurysm. CONCLUSIONS: Ruptured irregularly shaped aneurysms may be accompanied by fragile pseudoaneurysm-like cavities located at the rupture point. Because these aneurysms have a high risk of repeated rupture during an endovascular procedure, advancing microinstruments to the weaker portion of the aneurysm should be avoided.

Adult↗