Abstract
Background The specific binding ratio (SBR), an objective indicator of N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-[123I] iodophenyl) nortropane ([123I]FP-CIT) single photon emission computed tomography (SPECT) could be used for the diagnosis of Parkinson' disease and dementia with Lewy bodies. One of the problems of SBR analysis is the setting position of the volume of interest (VOI) might contain cerebral ventricles and cerebral groove. These areas become prominent in analysis with brain atrophy, however these studies have not been done sufficiently. Results We examined the influence of brain atrophy in SBR analysis using Monte Carlo simulation. The brain atrophy model (BAM) which set the simulate of brain atrophy to 5 stages was prepared using morphological operation. Projection data was created based on BAM, and SPECT reconstruction was carried out. The counts of striatal VOI decreased as brain atrophy progresses. Similarly, the counts of the reference VOI also decreased as brain atrophy progressed. In the striatal VOI counts and the reference VOI counts, the reference VOI counts was more affected by brain atrophy than striatal VOI counts. The SBR calculated from these values was overestimated as brain atrophy progresses. Conclusions It was suggested that the SBR could be overestimated in the secular change of the case in which brain atrophy advanced.
Influence of Brain Atrophy using Semi-quantitative Analysis in [123I ]FP-CIT Single Photon Emission Computed Tomography: A Monte Carlo Simulation Study