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Biomedical subjects

M Kera

Publications and source records attributed to M Kera.

9 recordsLinked to original sources
PubMed1992

[Effect of scattering and spatial resolution on SPECT quantification values: experimental study using phantoms and clinical application].

The relative SPECT values are often inaccurate by the scattering and limited spatial resolution of single photon emission CT (SPECT). These effects were studied using phantoms and some attentions on clinical application were investigated. Using cylindrical phantom divided into six compartments filled with various radioactivities, the linear correlation between SPECT value and radioactivity, and also correlation with partial reduction of radioactivity were identified. But the SPECT value was relatively increased in proportion to the reduction of radioactivity due to the increase of scattering contribution. The SPECT value represented lower radioactivity when the cortical thickness was smaller than two times of FWHM and represented half radioactivity when the cortical thickness was equal to FWHM. Excellent correlation between SPECT value and radioactive partial volume averaging of brain with CSF was recognized using our hand made phantom simulating various degree of atrophic brain. It is very important to compare SPECT image with X-CT or MR image to avoid misreading taking the above mentioned effects due to scattering and limited spatial resolution.

Atrophy↗
PubMed1991

[Simultaneous assessment of wall motion and myocardial perfusion by technetium-99m methoxy isobutyl isonitrile].

The aim of this study was to assess whether or not myocardial uptake of Technetium-99m methoxy isobutyl isonitrile (Tc-MIBI) indicated myocardial viability. We performed simultaneous Tc-MIBI angiography and myocardial SPECT at rest on 12 patients with suspected coronary artery disease. Left ventricle was divided into 3 segments, and regional wall motion was graded as normal, hypokinesis and akinesis/dyskinesis. Myocardial uptake of Tc-MIBI was assessed as normal, reduced and absent in each segment. In segments with normal and reduced Tc-MIBI uptake, 7% (2 of 28) and 33% (2 of 6) showed wall motion abnormalities of akinesis/dyskinesis, respectively. However, all segments with absent Tc-MIBI uptake had asynergy of akinesis/dyskinesis (2 of 2, 100%). Myocardial Tc-MIBI uptake at rest indicated wall motion abnormalities and was considered to be useful for the evaluation of myocardial viability. First-pass radionuclide angiography followed by myocardial SPECT with Tc-MIBI demonstrated to be useful for the simultaneous assessment of the left ventricular wall motion and myocardial perfusion.

Coronary Circulation↗
PubMed1990

[A phase III multi-center clinical trial on 123I-orthoiodohippurate (123I-OIH)].

A multi-center clinical trial was performed to evaluate the clinical usefulness of 123I-orthoiodohippurate (123I-OIH) in patients with renal and urinary disorders. 123I-OIH was evaluated to be "safe" in all 259 cases it was injected. 123I-OIH was useful in all 248 cases analyzed for the overall clinical usefulness evaluated by the investigators. The clinical significance of the drug was also evaluated in terms of renal blood flow function, renal parenchymal function, urinary function and the ability to differentiate between renal and urinary disorders. In the comparison with 123I-OIH (90 cases), 123I-OIH was superior as evaluated by the investigators and the Committee both. In the comparison with 99mTc-DTPA (113 cases), 123I-OIH was evaluated as superior by the investigators, but no significant difference was found by the Committee. In image qualities, 123I-OIH was evaluated as superior to 131I-OIH and equal to 99mTc-DTPA by the Committee. In overall efficiency, 123I-OIH was evaluated as being more valuable than 131I-OIH in 92% of the 90 cases and more valuable than 99mTc-DTPA in 50% of the 113 cases. 123I-OIH was evaluated as being less valuable than 131I-OIH in no cases and less valuable than 99mTc-DTPA in 7% of the 113 cases. These results suggest that 123I-OIH is superior to 131I-OIH and equal or superior to 99mTc-DTPA as a radiopharmaceutical for gamma camera-renography.

Clinical Trials as Topic↗
PubMed1990

[Cerebral blood flow and brain size in healthy subjects--sensitivity to age and gender].

Cerebral blood flow was measured in 56 healthy subjects who ranged in age from 1.3 to 80 years. The Xe-133 inhalation method with ring type single photon emission computed tomography (SPECT); HEADTOME was used. The cerebral blood flow were calculated by the method of Kanno & Lassen. Then the value were corrected for end-tidal CO2 concentration that had an excellent correlation with PaCO2 and was one of the most sensitive factors to change cerebral blood flow. The brain-size index was obtained by measuring the lateral and antero-posterior diameters from the SPECT images. The mean cerebral blood flow in children less than five years of age was 90-100 ml/100 g/min that was approximately twice that found in adults. The mean cerebral blood flow decreased rapidly with age until 24.0 years of age in male and 21.7 in female. Thereafter, there was a slow decrease and a negative correlation with age was found. In adults, the mean value of the cerebral blood flow of females was slightly higher than that of males (p less than 0.01). In contrast, the brain-size index of females was significantly smaller than that in males (p less than 0.01). There was a significant negative correlation to an inverse proportionality of cerebral blood flow and brain-size index (p less than 0.002). But, there was no significant correlation between total flow index that obtained to multiplied mean flow by brain-size index and brain-size index or gender.

Adolescent↗
PubMed1989

[Effect of breathing fluctuations on cerebral blood flow in demented patients and its correction method using end-tidal CO2 concentration].

During mouthpiece respiration of Xe-133 for a measurement of regional cerebral blood flow (rCBF), the breathing pattern of patients fluctuated and it caused a change of end-tidal CO2 concentration that had an excellent correlation with PaCO2 in patient without respiratory disease. The end-tidal CO2 concentration of demented patients varied within lower ranges than senile control group. The range of fluctuation on the end-tidal CO2 concentration was dependent on the type and the degree of dementia, and it fluctuated most widely at the middle stage of Alzheimer disease. Mean cerebral blood flow increased by 13.9% for each 1% increase in end-tidal CO2 concentration (3.6%/mmHg PaCO2) in the case of demented patients without cerebrovascular disease. To improve the reliability of rCBF in demented patients, especially in Alzheimer disease, the correction of rCBF data for end-tidal CO2 concentration should be performed.

Adult↗
PubMed1988

Assessment of demented patients by dynamic SPECT of inhaled xenon-133.

We studied the potential for using dynamic single photon emission computed tomography of inhaled xenon-133 (133Xe) gas in the assessment of demented patients. An advanced ring-type single photon emission computed tomography (SPECT) "HEADTOME" with improved spatial resolution [15 mm in full width at half maximum (FWHM)] was used for tomographic measurement of regional cerebral blood flow (rCBF). All 34 patients underwent a detailed psychiatric examination and x-ray computed tomography scan, and matched research criteria for Alzheimer's disease (n = 13), senile dementia of the Alzheimer type (n = 9), or multi-infarct dementia (n = 12). In comparison with a senile control group (n = 7), mean CBF of both the whole brain and the temporo-parietal region was significantly less in the Alzheimer's disease and senile dementia Alzheimer type groups, but no significant difference was seen between the senile control group and multi-infarct dementia group. The correlation was 0.72 (p less than 0.004) between the mean CBF of the whole brain and the score of Hasegawa's Dementia Scale, and 0.94 (p less than 0.0001) between rCBF of the temporo-parietal region and the scale in Alzheimer's disease. In the senile dementia Alzheimer type group, the correlations were 0.77 (p less than 0.01) and 0.83 (p less than 0.004) respectively. No significant correlations were found in the multi-infarct dementia group. A temporo-parietal reduction in the distribution of the rCBF characteristic in the Alzheimer's disease group and a patchy whole brain reduction characteristic in the multi-infarct dementia group was detected. The ability of our improved SPECT to provide both quantitative measurement of rCBF and characteristic rCBF distribution patterns, makes it a promising tool for research or routine examination of demented patients.

Adult↗
PubMed1986

Fat in the normal cavernous sinus.

The cavernous sinuses of 17 patients examined by metrizamide CT cisternography with 1.5 mm-thick slices were reviewed. Most of the cavernous sinuses contained fatty components. Anterior lateral end and posterior end of the cavernous sinus are the common sites where the fat is visible.

Adipose Tissue↗