Optimization of Parameters for Quantitative Analysis of ¹²³ I-ioflupane SPECT Images for Monitoring of Progression of Parkinson's Disease

摘要： Objectives: Quantitative assessment of dopamine transporter (DAT) imaging can aid in diagnosing Parkinson’s disease (PD) and assessing disease progression in the context of therapeutic trials. Previously, the software program SBRquant was applied to 123I-ioflupane SPECT images acquired on healthy controls and subjects with PD. Earlier work on optimization of the parameters for differentiating between controls and subjects with dopaminergic deficits is extended here for maximizing change measurements associated with disease progression on longitudinally acquired scans. Methods: Serial 123I-ioflupane SPECT imaging for 51 subjects with PD (conducted approximately 1 year apart) were downloaded from the Parkinson’s Progression Markers Initiative database. The software program SBRquant calculates the Striatal Binding Ratio (SBR) separately for the left and right caudate and putamen regions of interest (ROI). Parameters were varied to evaluate the number of summed transverse slices and the positioning of the striatal ROIs for determining signal to noise associated with their annual rate of change in SBR. The parameters yielding the largest change of the lowest putamen's SBR from scan 1 to scan 2 were determined. Results: For the change from scan 1 to scan 2 in the 51 subjects, the largest annual change was observed when the putamen ROI was placed 3 pixels away from the caudate and by summing 5 central striatal slices. This resulted in an 11.2 ± 4.3% annual decrease in the lowest putamen's SBR for the group. Conclusions: Quantitative assessment of DAT imaging for assessing progression of PD requires specific, optimal parameters different than those for diagnostic accuracy.