A1 Refereed original research article in a scientific journal
STIMULATION-ACTIVATION STUDY USING (H2O)-O-15 AND PET - PRINCIPLE AND METHOD
Authors: KANNO I, FUJITA H, IIDA H, LAW I
Publisher: BIOMED RES FOUND
Publication year: 1992
Journal: Biomedical Research
Journal name in source: BIOMEDICAL RESEARCH-TOKYO
Journal acronym: BIOMED RES-TOKYO
Volume: 13
First page : 45
Last page: 50
Number of pages: 6
ISSN: 0388-6107
Abstract
The theoretical principle and method using H-2 O-15 and PET was described. Owing to a short tracer half-life (123 s), we can repeat measurements at a short interval for in vivo investigation of the higher brain functions. The method calculates CBF from time-integration of the H-2 O-15 distribution in brain tissue measured by PET. We have searched the method to optimize single to noise ratio in the temporal and spatial domains to maximize the signal-to-noise ratio. Optimal scantime of accumulation after bolus injection of H-2 O-15 was found to be from 90 to 120 s. A slow input method for temporal smooth of CBF fluctuation did not show any benefit compared to the bolus injection method. In spatial domain, an increase in full-width at half-maximum (FWHM) of reconstruction filter reduced statistical noise more rapidly than the signal deterioration. A phantom experiment directly showed that the larger FWHM gave a higher statistical t-value. In averaging inter-subject data, we transform individual brain into a standard brain atlas. The standardization allows us anatomical registration of activation foci. The Talairach atlas based on the anterior-commissure posterior-commissure (AC-PC) line is most commonly used. This adjusts brain size linearly in x, y and z directions. Non-linear techniques have also been developed by several other groups. Finally, we have described several topics from our experiences with stimulation-activation studies. Somatosensory and motor stimulation clearly activates circumscribed areas. But the language tasks on the other hand provides many weak foci in both hemispheres.
The theoretical principle and method using H-2 O-15 and PET was described. Owing to a short tracer half-life (123 s), we can repeat measurements at a short interval for in vivo investigation of the higher brain functions. The method calculates CBF from time-integration of the H-2 O-15 distribution in brain tissue measured by PET. We have searched the method to optimize single to noise ratio in the temporal and spatial domains to maximize the signal-to-noise ratio. Optimal scantime of accumulation after bolus injection of H-2 O-15 was found to be from 90 to 120 s. A slow input method for temporal smooth of CBF fluctuation did not show any benefit compared to the bolus injection method. In spatial domain, an increase in full-width at half-maximum (FWHM) of reconstruction filter reduced statistical noise more rapidly than the signal deterioration. A phantom experiment directly showed that the larger FWHM gave a higher statistical t-value. In averaging inter-subject data, we transform individual brain into a standard brain atlas. The standardization allows us anatomical registration of activation foci. The Talairach atlas based on the anterior-commissure posterior-commissure (AC-PC) line is most commonly used. This adjusts brain size linearly in x, y and z directions. Non-linear techniques have also been developed by several other groups. Finally, we have described several topics from our experiences with stimulation-activation studies. Somatosensory and motor stimulation clearly activates circumscribed areas. But the language tasks on the other hand provides many weak foci in both hemispheres.
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