Biomedical subjects

Setsu Sakamoto

Publications and source records attributed to Setsu Sakamoto.

6 recordsLinked to original sources

PubMed2003

[Diagnostic imaging--recent progress].

Current advances in the diagnostic imaging for lung cancer includes multidetector-row CT (MDCT), lung cancer screening using low-dose MDCT and fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. There is no question about the clinical usefulness of MDCT, and the further development of the hardware and the software of MDCT will open new horizons for CT diagnosis. PET is not an alternative modality to CT but a supplementary one, which adds metabolic information to the morphology. Recently, experimental research on the refraction imaging of human lung specimens has been performed with synchrotron radiation. With progressive refinement, this technique may come to have some practical purpose in diagnosing lung cancer in vivo.

Carcinoma, Squamous Cell↗

PubMed2002

Differences in cerebral metabolic impairment between early and late onset types of Alzheimer's disease.

UNLABELLED: The purpose of this study was to delineate the specific patterns of cerebral glucose metabolism with regard to the time of onset of Alzheimer's disease (AD). METHODS: Two groups of 20 AD patients with different ages of onset were examined. The early onset (EO) and late onset (LO) groups had mean ages of onset of 53.9 and 72.7 years. Groups of age-matched normal subjects were used as controls. A regional relative cerebral glucose metabolic image of each subject was obtained by 2-[18F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). NEUROSTAT program was used for spatial normalization and voxel-based statistical parametric mapping (SPM) 99 was used for statistical analyses. RESULTS: Both AD groups had significant hypometabolic regions in the bilateral parieto-temporal regions compared with the age-matched groups. The EO group had more severe hypometabolism in the bilateral parietal and posterior cingulate cortices and precuneus region than the LO group. However, LO group showed no significant hypometabolic regions compared to the EO group. CONCLUSION: The effects of time of AD onset were delineated as a double dissociation, that is, EO AD patients have a more severe reduction of glucose metabolism. Our finding suggests the existence of biological subtypes of AD.

Adult↗

PubMed2002

Voxel-based comparison of regional cerebral glucose metabolism between PSP and corticobasal degeneration.

OBJECTIVES: Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are neurodegenerative disorders that may be accompanied by dementia and parkinsonism as clinical symptoms. The purpose of this study was to elucidate cerebral metabolic differences of these two diseases with cognitive impairments by [18F] fluorodeoxyglucose (FDG) and positron emission tomography (PET). METHODS: A total of 12 patients with PSP (age: 62.8+/-6.0 years old, m: 7, f: 5, Mini-Mental State Examination (MMSE): 23.4+/-2.6), 12 patients with CBD (age: 64.8+/-6.3 years old, m: 6, f: 6, MMSE: 22.9+/-4.5), and age-matched healthy subjects (normal control (NC)) (age: 63.8+/-7.7 years old, m: 7, f: 5) were subjected to FDG-PET to obtain glucose metabolic images. We compared regional cerebral metabolic images by a voxel-by-voxel analysis with statistical parametric mapping (SPM) among PSP, CBD, and NC subjects, and evaluated differences of hypometabolic regions. RESULTS: The patients with PSP showed reduced cerebral glucose metabolism in the medial and lateral frontal gyri, basal ganglia, and midbrain compared with NC, whereas the patients with CBD showed significant reduction in the parietal lobes (p<0.001). SPM also revealed parietal hypometabolism in CBD patients compared with PSP patients (p<0.001). CONCLUSIONS: The predominant parietal glucose metabolic reduction in CBD patients was different from previously reported findings. This finding would be the characteristic substance of patients with CBD accompanying cognitive impairments. Our findings suggest that measurement of glucose metabolism by PET and a voxel-based analysis is useful to understand the pathophysiology of these two diseases with cognitive impairments.

Brain↗

PubMed2002

Gender differences in cerebral glucose metabolism: a PET study.

OBJECTIVE: Some studies have examined gender differences in brain function based on cerebral blood flow and cerebral metabolism by using positron emission tomography (PET). However, the findings of these studies are controversial and most of them were analyzed by the regions of interest (ROIs) method. Here, we evaluated gender differences of cerebral glucose metabolism under the resting state in a voxel-based analysis. METHODS: We studied 44 healthy volunteers (22 females, 63.0+/-6.3 years, and 22 males, 63.1+/-8.4 years). Cerebral glucose metabolic images were obtained with (18)F-fluorodeoxyglucose (FDG) and PET. All individual data were transformed to standard brain space and the male and female groups were compared using statistical parametric mapping (SPM). RESULTS: The males had significantly higher glucose metabolism in the right insula, middle temporal gyrus, and medial frontal lobe than the females. Glucose metabolism in the hypothalamus was significantly higher in females than in males. There was a significant correlation between aging and glucose metabolism in the left thalamus in males and in the left caudate nucleus and hypothalamus in females. In males, but not females, there was a significant asymmetry between the bilateral hemispheres. CONCLUSION: We found that there were obvious gender differences in regional cerebral glucose metabolism and this is the first report of higher glucose metabolism in the hypothalamus in females than in males.

Aged↗

PubMed2002

Variation in FDG uptakes in different regions in normal human brain as a function of the time (30 and 60 minutes) after injection of FDG.

OBJECTIVE: The authors' goal was to determine whether FDG uptakes in various regions of the brain are different for early and late scanning time in positron emission tomography (PET). METHOD: F-18 fluorodeoxyglucose (FDG) PET was performed on 15 healthy normal subjects to obtain early and late acquisition glucose metabolic images (30 and 60 min after FDG injection), respectively. The two sets of images were compared in a voxel-by-voxel analysis. RESULTS: In the bilateral posterior cingulate gyrus, parietal and frontal association cortices, and subcallosal cortices, the FDG uptakes were larger on the late scan image than on the early scan image, and the FDG uptakes were larger in the cerebellar hemisphere, vermis and frontal basis on the early scan image than on the late scan image. CONCLUSIONS: These results suggest that there are different regional FDG uptakes depending on the scanning time after FDG injection and we must be careful in replacing conventional FDG PET scanning with early scanning in FDG PET study.

Aged↗

PubMed2002

[Performance evaluation of continuous blood sampling system for PET study: comparison of three detector-systems].

OBJECTIVES: To measure cerebral blood flow with 15O'PET, it is necessary to measure the time course of arterial blood radioactivity. We examined the performance of three different types of continuous blood sampling system. METHODS: Three kinds of continuous blood sampling system were used: a plastic scintillator-based beta detector (conventional beta detector (BETA)), a bismuth germanate (BGO)-based coincidence gamma detector (Pico-count flow-through detector (COINC)) and a Phoswich detector (PD) composed by a combination of plastic scintillator and BGO scintillator. Performance of these systems was evaluated for absolute sensitivity, count rate characteristic, sensitivity to background gamma photons, and reproducibility for nylon tube geometry. RESULTS: The absolute sensitivity of the PD was 0.21 cps/Bq for 68Ga positrons at the center of the detector. This was approximately three times higher than BETA, two times higher than COINC. The value measured with BETA was stable, even when background radioactivity was increased. The count rate characteristic of the PD and COINC was linear up to 8 kcps. The reproducibility of sensitivity for nylon tube geometry of COINC was the smallest (C.V. = 1.00%) among the three. PD was the weights the least (3.5 kg) among the three, which is convenient for clinical use. CONCLUSIONS: Each detector has unique characteristics derived from its own structure. Although the performance of all three detectors meets clinical requirement, PD had the highest physical performance.

Cerebrovascular Circulation↗