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Correction for partial-volume effects on brain perfusion SPECT in healthy men
Hiroshi Matsuda1, Takashi Ohnishi, Takashi Asada
1Department of Radiology, National Center Hospital for Mental, Nervous, and Muscular Disorders, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashi, Kodaira, 187-8551 Tokyo, Japan. matsudah@ncnpmusashi.gr.jp
Summary
Partial-volume effects (PVEs) in SPECT brain imaging can be corrected to improve accuracy. This study found that PVE correction enhances the homogeneity of regional cerebral blood flow (rCBF) measurements and reveals age-related changes in specific brain regions.
Area of Science:
- Neuroimaging
- Nuclear Medicine
- Radiology
Background:
- Single-photon emission computed tomography (SPECT) has limited spatial resolution, leading to partial-volume effects (PVEs) that underestimate radiotracer concentration in small brain structures.
- These PVEs can affect the accuracy of regional cerebral blood flow (rCBF) measurements in brain SPECT studies.
Purpose of the Study:
- To identify brain structures most affected by PVEs in SPECT studies of healthy volunteers.
- To investigate the impact of aging on SPECT measurements after PVE correction.
Main Methods:
- Brain perfusion SPECT using 99mTc-ethylcysteinate dimer was performed on 52 healthy men (18-86 years old).
- Regional cerebral blood flow (rCBF) was measured noninvasively using graphical analysis.
- SPECT images were corrected for PVEs using gray-matter volume segmented from MRI, and correlations with age were examined before and after correction. A phantom experiment validated the correction method.
Main Results:
- PVE correction significantly reduced the coefficient of variation for SPECT counts and improved the homogeneity of rCBF distribution, decreasing intersubject variability.
- Significant negative correlations between age and adjusted rCBF were observed in bilateral perisylvian and medial frontal areas, persisting after PVE correction.
- PVE correction shifted positive age-related rCBF correlations from medial temporal to sensorimotor and parietal areas.
Conclusions:
- SPECT imaging reflects both brain volume loss and functional changes.
- PVE correction in brain perfusion SPECT enables more accurate rCBF determination, even in healthy individuals.