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Biomedical subjects

F Shishido

Publications and source records attributed to F Shishido.

At least 109 records · Page 6Linked to original sources
PubMed1986

Positron emission tomography in patients with a primary intracerebral hematoma.

Using positron emission tomography, the regional cerebral blood flow (CBF), oxygen extraction fraction (OEF) and oxygen consumption (CMRO2) were studied in 21 patients with hypertensive intracerebral hematomas. The study showed a very localized decrease of CBF and CMRO2 around a hematoma, and revealed in two cases (9.1%) distinct luxury perfusion around it. There was diffuse reduction of CBF with increased OEF in hematomas larger than 4.5 cm in diameter. The results suggested that surgical evacuation should be considered for hematomas with a diameter exceeding 4.5 cm.

Adult↗
PubMed1986

Regional cerebral blood flow and metabolism in patients with chronic obstructive carotid disease.

Regional cerebral blood flow (CBF), oxygen extraction fraction (OEF) and oxygen consumption (CMRO2) were studied by PET in 26 patients with chronic occlusion(s) or severe stenosis of the internal carotid or middle cerebral artery(ies) without a large (greater than 2 cm) infarction. Most of them showed a coupled decrease of CBF and CMRO2 in the internal carotid distribution. In 5 patients (19%), the CBF in the least perfused but structurally normal tissue was reduced to critically low values while maintaining CMRO2, considerably increasing OEF. Since detection of a lesion with hemodynamic insufficiency was important for the indication for an EC/IC bypass operation, only 19 per cent of the present series would have had an indication for surgery.

Blood Volume↗
PubMed1986

[In vivo measurements of regional cerebral hemocirculation and metabolism in gliomas using 15O and 18F-fluorodeoxyglucose positron emission tomography].

A high resolution PET-HEADTOME III has been employed to quantitate regional cerebral hemodynamics and metabolism in gliomas using O-15 and 18FDG tracers, and to evaluate histological malignancy preoperatively. Hemodynamic and metabolic indices of regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen consumption (rCMRO2), oxygen extraction (rOEF), and glucose consumption (rCMRGl) were studied on thirteen preoperative gliomas involving one recurrent case. Regions of interest (ROIs) on PET were placed over the corresponding lesions in CT scans. In high grade gliomas, ROIs were also focused on the corresponding parts of central low density area, contrast enhanced area, and peritumoral low density area. rCBF and rCBV were variable and unrelated in both low and high grade gliomas. rCMRGl values were 5.99 +/- 3.99 mg/100 ml/min for high grade gliomas, and 3.01 +/- 0.48 mg/100 ml/min for low grade gliomas. Lesions with high uptake of radioisotope were proved to be high grade gliomas. lesions with low uptake being low grade gliomas. In comparison with the contralateral gray matter around the sylvian fissure, rCBV was significantly higher(p less than 0.02) in high grade gliomas, and rCMRGl was lower (p less than 0.05) in low grade gliomas. rCMRO2 and rOEF values were reduced markedly (p less than 0.01) in both low and high grade gliomas. These results support that anaerobic glycolysis increased with malignancy in the metabolism of gliomas. The hemodynamics and metabolism of central low density area and peritumoral low density area reflect the pathophysiological state of necrosis and edema respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Glucose metabolism in ischemic myocardium: quantitative imaging using positron emission tomography].

We determined the myocardial metabolic rate for glucose (MMRGlc) in the ischemic or infarcted myocardium using 18-F-fluorodeoxyglucose (18-FDG) with positron emission tomography (PET), and studied energy metabolism in the ischemic myocardium. In some cases, we compared glucose metabolism images by 18-FDG with myocardial blood flow images using 15-oxygen water. Two normal subjects, seven patients with myocardial infarction and four patients with angina pectoris were studied. Coronary angiography was performed within two weeks before or after the PET study to detect ischemic areas. PET studies were performed for patients who did not eat for 5 to 6 hours after breakfast. Cannulation was performed in the pedal artery to measure free fatty acid, blood sugar, and insulin. After recording the transmission scan for subsequent correction of photon attenuation, blood pool images were recorded for two min. after the inhalation of carbon monoxide (oxygen-15) which labeled the red blood cells in vivo. After 20 min., oxygen-15 water (15 to 20 mCi) was injected for dynamic scans, and flow images were obtained. Thirty min. after this procedure, 18-FDG (5 to 6 mCi) was injected, and 60 min later, a static scan was performed and glucose metabolism images were obtained. Arterial blood sampling for the time activity curve of the tracer was performed at the same time. According to the method of Phelps et al, MMRGlc was calculated in each of the region of interest (ROI) which was located in the left ventricular wall. MMRGlc obtained from each ROI was 0 to 17 mg/100 ml/min. In normal subjects MMRGlc was 0.4 to 7.3 mg/100 ml/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Positron CT imaging using a high resolution PCT device (Positologica-I), 11CO, 13NH3, and 18FDG in clinical evaluation of cerebrovascular diseases.

Positron computed tomography (PCT) was performed in 3 normal volunteers and 21 patients with cerebrovascular diseases using a high resolution PCT device 'Positologica-I' and three tracers 11CO, 13NH3, and 18FDG. Relatively early lesions showed various accumulation patterns, and metabolism and perfusion mismatches were clearly shown by this measurement. One type of mismatch is luxury perfusion which had a slight increase of blood volume. Another type of uncoupling is misery perfusion. Remote effects of ischemic lesions also appeared on PCT with 18FDG and 13NH3. From our clinical results, the PCT method with a high resolution device and radiopharmaceuticals such as 11CO, 13NH3, and 18FDG is very useful in the assessment of cerebrovascular diseases and in defining circulatory dysfunction in man.

Adolescent↗