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Biomedical subjects

M Kowada

Publications and source records attributed to M Kowada.

226 records · Page 13Linked to original sources
PubMedDate not supplied

Three-dimensional computed tomography in the head and neck diseases with bony abnormalities.

The purpose of this study was to define the role of three-dimensional (3D) computed tomography (CT) in the head and neck diseases with bony abnormalities. Thirty-two patients were examined with a low dose radiation technique. Three-dimensional CT clearly delineated bony lesions in 27 of 32 patients. Three-dimensional CT could not demonstrate subtle bony erosions infiltrated by tumor, a temporal bone fracture, and a blow-out fracture, although two-dimensional (2D) images obtained before the 3D reconstructions clearly depicted those lesions. These two kinds of CT technique were thought to be complimentary.

Bone Diseases↗
PubMedDate not supplied

Increased blood flow in human brain tumor after administration of angiotensin II: demonstration by PET.

To evaluate the changes of regional cerebral blood flow (CBF) in artificial hypertensive state, we investigated vascular responses to changes of arterial carbon dioxide tension (PCO2) and blood pressure by means of positron emission tomography (PET). The subjects were eight brain tumors which were histologically proven. We calculated CBF changes in hypercapnic and hypocapnic state, and then using those results, CBF changes in hypertensive state were corrected. Every patient represented a selective increase of tumor blood flow in hypertensive state induced by angiotensin II, demonstrating a loss of autoregulation in tumor. Our results suggested the possibility of enhancement of chemotherapy for brain tumors.

Adult↗
PubMedDate not supplied

Computed tomography of an intracranial lipoma confined in the suprasellar cistern.

A case of large intracranial lipoma involving the suprasellar cistern is presented in a 50-yr-old man with a history of occipital headaches. Evaluations by routine computed tomography (CT) combined with metrizamide CT cisternography were extremely useful in the diagnosis of this rare condition. Intracranial lipomas are reviewed in the literature and the role of CT evaluations is discussed.

Brain Neoplasms↗
PubMedDate not supplied

Orbital hemangiopericytoma: CT, MR, and angiographic findings.

A case of orbital hemangiopericytoma is reported in a 20-yr-old man presenting with decreased vision and painless proptosis of the left eye. This rare orbital tumor is reviewed in the literature, and in particular the neuroradiological findings, including those of computerized tomography (CT), magnetic resonance imaging (MRI), and angiography are detailed in the presented case. MRI was found to be useful both in delineating precise anatomical relationships between the optic nerve and the tumor, and in differentiating from cavernous hemangiomas, the most common vascular tumors of the orbit, with the combination of CT and angiography.

Adult↗
PubMedDate not supplied

Early delineation of cerebral glioma using amino acid positron tracers.

A 56-yr-old housewife with cerebral astrocytoma was reported with positron emission tomography findigns using 11C-methyl-L-methionine (11C-Met) and 18F-fluorophenylalanine (18F-Phe) tracers. 11C-Met and 18F-Phe accumulated intensely in tumor lesions, although CT scans showed only a foggy low-density area. Five years and one month after, an enhancing mass appeared on CT scans. Thus, amino acid tracers may play a important role in the early diagnosis of gliomas.

Astrocytoma↗
PubMedDate not supplied

Positron emission tomographic evaluations in the diagnosis and therapy of multifocal glioblastoma. Report of a pediatric case.

A pediatric case of multifocal glioblastoma is reported with special reference to positron emission tomography (PET) evaluations in the diagnosis and therapy. A PET scan employing 15O and 18F positron tracers disclosed a right thalamic lesion high in regional cerebral blood flow, cerebral blood volume and metabolic glucose rate, suggesting a malignant tumor. In contrast, a left frontal lesion with low regional cerebral blood flow, cerebral blood volume and metabolic glucose rate was presumed to be rather hypodynamic and hypometabolic. Histological examination of these isolated masses showed both to be glioblastomas, and, as predicted by the PET findings, there were minor histological distinctions. In repeated PET scans following postoperative combined radiochemotherapy, metabolic glucose rate values at the thalamic tumor decreased to about 50% the levels before therapy, although there was no distinguishable change in tumor size on the concurrent computerized tomography scans. This therapeutic efficacy on tumor metabolism was highly consistent with the period of clinical relief.

Brain Neoplasms↗
PubMedDate not supplied

Demonstration of cerebral radiation injury with metabolic positron emission tomography images.

A 2-year-old girl with medulloblastoma who had postoperative radiotherapy and intrathecal administration of methotrexate is reported. Five months after radiation and chemotherapy, she developed involuntary movement. Positron emission tomography (PET) demonstrated that the metabolic rate of glucose was depressed markedly in the temporal and occipital lobes, indicative of metabolic depression induced by radiation. Prompt initiation of steroid therapy ameliorated the patient's neurological symptoms. Follow-up PET revealed an increase in 18F-fluorodeoxyglucose uptake in the entire brain, including temporal and occipital lesions. No areas with high accumulation of (11C-methyl)-L-methionine were detectable. We concluded that PET may be useful in establishing an early diagnosis of radiation injury of the brain and in monitoring metabolic changes following radiation in brain tumor patients.

Blood Glucose↗
PubMedDate not supplied

Superselective angio-CT of brain tumors.

PURPOSE: To determine the efficacy of superselective angio-CT in the diagnosis of astrocytoma. METHODS: Nineteen patients with astrocytoma had superselective angio-CT before chemotherapeutic agents were administered via superselective intraarterial infusion. CT was performed after contrast material was delivered through a microcatheter, which had been advanced into the feeding arteries of the tumor. Superselective angio-CT scans were compared with digital subtraction angiograms, conventional contrast-enhanced CT scans, and contrast-enhanced T1-weighted MR images. RESULTS: Superselective angio-CT scans depicted contrast enhancement of the tumor in all of the patients and the medullary veins of the tumors in 32% of the patients. Digital subtraction angiograms showed tumor stains in 68% of the patients and the medullary veins in only 5%. Conventional CT scans and MR images showed contrast enhancement of the tumor in 89% of the patients. Superselective angio-CT scans confirmed the proper position of the catheter tip for the infusion of a chemotherapeutic agent. CONCLUSIONS: Superselective angio-CT can be used to depict contrast enhancement of tumors and the vascular structures that are characteristic of astrocytomas.

Adult↗
PubMedDate not supplied

Central neurocytoma with clinically malignant behavior.

We describe two cases of central neurocytoma that did not show histopathologic features of anaplasia but did show tumor dissemination after surgery and radiation therapy. CT and MR imaging before surgery depicted extraventricular extension of the tumors. The importance of radiologic findings is stressed.

Adult↗