Partial-volume correction increases estimated dopamine D2-like receptor binding potential and reduces adult age...

Area of Science:

• Neuroimaging
• Radiochemistry
• Gerontology

Background:

• Positron emission tomography (PET) spatial resolution limits can cause partial volume effects (PVEs).
• PVEs may lead to underestimation of binding potential (BPND), particularly in aging brains with grey matter loss.
• This can result in overestimation of age-related changes in dopamine D2-like receptors.

Purpose of the Study:

• To investigate the impact of partial volume correction (PVC) on BPND estimates.
• To assess how PVC affects the observed age-related differences in dopamine D2-like receptor availability.
• To compare the efficacy of PVC across different PET scanner resolutions and radioligands.

Main Methods:

• Two independent studies utilizing different D2-like radioligands (18F-Fallypride, 11C-FLB457) and PET scanner resolutions (∼5mm, 2.5mm).
• Application of PVC to PET data to correct for PVEs.
• Analysis of BPND changes and age effects before and after PVC.
• Comparison with uncorrected data controlling for grey matter volume.

Main Results:

• PVC consistently increased estimated BPND across both datasets.
• PVC reduced, but did not eliminate, age-related effects on BPND.
• The impact of PVC was more pronounced with lower-resolution PET data.
• Grey matter volume correction in uncorrected data partially mimicked PVC effects in some regions.

Conclusions:

• PVC enhances BPND quantification in PET imaging.
• PVC is crucial for accurately assessing age-related changes in dopamine D2-like receptor availability, especially with lower-resolution scanners.
• Previous research on dopamine receptor availability, often lacking PVC, may have overestimated aging effects.