Semiautomatic quantitative analysis of F-18 FP-CIT PET in Parkinson’s disease: Comparison with drug-induced parkinsonism and healthy controls

초록

Objectives The aim of this study was to evaluate the differential diagnosis and quantitation of striatal binding of F-18 FP-CIT PET using the semiautomatic quantitative analysis in patients with de novo Parkinson’s disease (PD). Methods Sixty de novo PD (65.6±9.8 y; M:F=26:34), 20 DIP (70.8±6.5 y; M:F=7:13) and 7 HC (65.9±9.4 y; M:F=3:4) who underwent F-18 FP-CIT PET/CT were enrolled. Among the PD group, 9 patients (15%) had visually normal findings, so they were regrouped as scans without evidence of dopaminergic deficit (SWEDDs). Mean counts were obtained using the FP-CIT template-based semiautomatic quantification program as our previous works. Putamen-to-caudate ratio (PCR), asymmetry index (ASI), ratios of specific (striatum, caudate, putamen) to nonspecific (occipital) area; V3(S), V3(C), V3(P) were compared, respectively. Analysis of variance tests, ROC curves and Pearson correlation were performed for each parameter. Results PCR, V3(S), V3(P) in PD were significantly lower than those in DIP and HC groups (P<0.001). Cut-off values for PD were established at 1.05 in PCR (sensitivity:100%, specificity:85%, AUC:0.95) and at 2.44 in V3(P) (93%, 88%, 0.93, respectively). We also found significant differences in PCR, V3(S), V3(P) between SWEDDs and non-SWEDDs (P<0.001). There was a significant inverse correlation with UPDRS motor score and V3(P) in non-SWEDDs group (R=-0.28, p=0.04). In addition, SWEDDs were distinguishable from DIP and HC as well as non-SWEDDs on all quantitative ratios except V3(C). Conclusions This study showed a simple, objective and accurate method to discriminate patients with PD from those with DIP and HC, using the semiautomatic quantitative analysis. Quantitative indexes also provided low striatal FP-CIT uptake even in SWEDDs, compared to DIP and HC groups. These findings could provide clues in understanding the pathophysiology of SWEDDs in a future study.