~(123)I-FP-CIT SPECTにおける画像再構成方法が定量性と診断能に与える影響

摘要

~(123)I-N-ω-fluoropropyl-2β-carboxymethoxy-3β-(4-iodophenyl)nortropane(~(123)I-FP-CIT)single photon emission computed tomography(SPECT)を用いた線条体イメージングはパーキンソン病ゃレビー小体型認知症の鑑別診断に有用とされている，また，~(123)I-FP-CITの線条体に対する特異的結合を定量的に表したspecific binding ratio(SBR)は，鑑別診断を行う際の客観的診断指標のひとつとして用いられている。%Purpose: This study evaluates the effect of reconstruction strategies for the quantification and diagnostic accuracy of ~(123)I-FP-CIT SPECT. Methods: We evaluated the quantification of ~(123)I-FP-CIT SPECT obtained by several combinations of reconstruction using the striatal phantom. The phantom images were reconstructed using FBP and OSEM with/without attenuation correction (AC) and scatter correction (SC). We calculated the specific binding ratio (SBR) using volume of interest (VOI) analysis on each reconstructed images. For the clinical study, 40 patients who underwent ~(123)T-FP-CIT SPECT were selected. We grouped the patients into the normal binding group and decreased binding group according to their clinical diagnosis. The clinical images were reconstructed under the same conditions as the phantom study. The SBRs were calculated, and a receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic accuracy. Results: The SBRs with AC and SC significantly increased compared with no corrections. In the clinical study, although ROC analysis showed no significant difference in the all combinations of reconstruction, the area under the curve using SC and AC tended to be higher than that obtained by other reconstruction. Conclusions: Quantification of ~(123)I-FP-CIT SPECT was affected by reconstruction strategies. In addition, both the AC and SC improved the diagnostic accuracy of ~(123)I-FP-CIT SPECT. Our results suggest that both the AC and SC are recommended for the improving the quantification and diagnostic accuracy in ~(123)I-FP-CIT SPECT.