Biomedical subjects

T Kamano

Publications and source records attributed to T Kamano.

95 records · Page 6Linked to original sources

PubMedDate not supplied

Quantitation of cerebral blood volume by 99mTc-DTPA-HSA SPECT.

The characteristics of technetium-99m diethylenetriaminepentaacetic acid human serum albumin (99mTc-DTPA-HSA) as an agent for quantitation of cerebral blood volume (CBV) were examined. The radioactivity after decay correction as a percentage of the activity at 10 minutes was 84.3 +/- 1.3% at 120 minutes after the injection of 99mTc-DTPA-HSA. Radioactivity was found exclusively in plasma, with little in blood cells. The blood retention of 99mTc-DTPA-HSA is sufficient, and its use in the quantitation of CBV omits the need for centrifugation of the blood sample. CBV quantified using the tracer and a SPECT system with a single-head rotating gamma camera was 4.09 +/- 0.60 ml/100 g brain, similar to values reported previously. Two serial SPECT scans provided similar images, and the CBV values determined by the two scans were closely correlated (p < 0.001). The high reproducibility suggests that the method may be used to monitor the cerebrovascular response to drugs. It was concluded that 99mTc-DTPA-HSA has useful properties for quantitative CBV measurement and that quantitation of CBV by 99mTc-DTPA-HSA SPECT is feasible using a system with a single-head rotating gamma camera.

Adult↗

PubMedDate not supplied

A new method for monitoring the cerebrovascular response to acetazolamide using 99mTc-DTPA-HSA.

We developed a new method for monitoring the cerebrovascular response to acetazolamide using technetium-99m diethylenetriaminepentaacetic acid human serum albumin (99mTc-DTPA-HSA). We infused 740 M Bq (20 mCi) of 99mTc-DTPA-HSA intravenously and carried out dynamic scanning of the anterior view of the head for 50 minutes. Ten minutes after the start of scanning, 1,000 mg of acetazolamide was injected intravenously. In three normal volunteers, the radioactivity in brain increased for an average of 8 minutes after the injection of acetazolamide and then remained relatively stable. The average of dilatation index [(peak count/the count just before acetazolamide injection-1)x 100] was 16.1. Our method enabled us to observe vasodilation caused by acetazolamide straight, and may be of value in assessing cerebral perfusion reserve easily and quantitatively.

Acetazolamide↗

PubMedDate not supplied

The optimum Butterworth-Wiener filter for I-123 IMP brain SPECT.

The optimum Butterworth-Wiener filter (BWF) for the preprocessing of N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) SPECT was determined by a simulation experiment. Sixty-four images of the brain phantom containing 14.8 MBq of I-123 IMP were collected with a gamma camera equipped with a slant hole collimator during a 360-degree rotation. The images were processed with 27 BWFs of different shapes, followed by SPECT image reconstruction and visual comparison. The optimum BWF had a cutoff frequency of 0.25/pixel, FWHM of four pixels, and constant of 0.05. The image quality was greatly affected by the cutoff frequency of BWF used for preprocessing.

Brain↗

PubMedDate not supplied

Measurement of cerebral blood flow with two-dimensional cine phase-contrast mR imaging: evaluation of normal subjects and patients with vertigo.

PURPOSE: The purpose of this study was to determine whether or not the vertebral flow of patients with vertigo and normal brain magnetic resonance (MR) images was decreased in comparison with normal controls. MATERIALS AND METHODS: Cerebral blood flow (CBF) was quantitatively measured by a two-dimensional phase contrast cine MR imaging technique in 24 normal controls (mean age, 38.6 years; range, 12-70) and 23 patients (mean age, 53.7 years; range, 19-76) with a 1.5 Tesla MR imaging unit. RESULTS: Inter- and intraobserver variation in blood flow measurements was small (r = 0.970, standard error of the estimate [SEE] = 2.9 ml, n = 80; r = 0.963, SEE = 4.6 ml, n = 40, respectively). In the normal group, mean summed vertebral flow (171 ml/min, SD = 40.6) was significantly less than mean summed carotid flow (523 ml/min, SD = 111). Right vertebral flow (80.2 ml/min, SD = 30.5) was less than left vertebral flow (91.2 ml/min, SD = 38.2), but the difference was not statistically significant (p < 0.05). In the 23 patients, although the summed vertebral flows of two patients (63.3, 88.8 ml/min) were significantly less than that of the normal group, mean summed vertebral flow (165 ml/min, SD = 59.1) showed no significant difference from that of the normal group (p < 0.05). CONCLUSIONS: In this study, the majority of patients had normal CBF. This method is clinically useful for estimating CBF.

Adolescent↗

PubMedDate not supplied

Influence of endotoxemia on hepatic energy metabolism in rats with obstructive jaundice.

BACKGROUND/AIMS: A secondary insult in patients with obstructive jaundice can lead to multiple system organ failure. We evaluated the influence of endotoxin on hepatic energy metabolism and hepatic tissue blood flow in obstructive jaundiced rats. MATERIAL AND METHODS: Male Sprague-Dawley rats were divided into a control group, an endotoxin administration group, an obstructive jaundice group, and an obstructive jaundice with endotoxin administration group. To evaluate hepatic energy metabolism, we have measured arterial blood ketone body ratio, and arterial blood total ketone body concentration. Hepatic tissue blood flow was determined by laser Doppler velocimetry. RESULTS: In the endotoxin administration group, no change was observed in hepatic energy metabolism. However, the obstructive jaundice group was associated with decreased hepatic tissue blood flow shortly after the outset of jaundice, while no change was observed in hepatic energy metabolism until 3 weeks later. In the obstructive jaundice with endotoxin administration, a significant decrease in hepatic tissue blood flow and an increase in hepatic energy metabolism were measured. CONCLUSION: Endotoxin administration alone had no influence on hepatic energy metabolism, while endotoxin administration in the presence of obstructive jaundice results in a rapid decrease in hepatic energy metabolism. This occurred as a result of the secondary insult of endotoxin in the setting of decreased hepatic tissue blood flow caused by obstructive jaundice.

Animals↗