PT - JOURNAL ARTICLE AU - Joachim Mazère AU - Willy Mayo AU - Guillaume Pariscoat AU - Jürgen Schulz AU - Michele Allard AU - Philippe Fernandez AU - Frédéric Lamare TI - Simplified Quantification Method for In Vivo SPECT Imaging of the Vesicular Acetylcholine Transporter with <sup>123</sup>I-Iodobenzovesamicol AID - 10.2967/jnumed.114.147074 DP - 2015 Jun 01 TA - Journal of Nuclear Medicine PG - 862--868 VI - 56 IP - 6 4099 - http://jnm.snmjournals.org/content/56/6/862.short 4100 - http://jnm.snmjournals.org/content/56/6/862.full SO - J Nucl Med2015 Jun 01; 56 AB - 123I-iodobenzovesamicol is a SPECT radioligand selective for the vesicular acetylcholine transporter (VAChT) and used to assess the integrity of cholinergic pathways in various neurologic disorders. The current noninvasive method for quantitative analysis of 123I-iodobenzovesamicol, based on multilinear reference tissue model 2 (MRTM2), requires repeated scans for several hours, limiting its application in clinical trials. Our objective was to validate a simplified acquisition method based on a single 123I-iodobenzovesamicol static scan preserving the quantification accuracy. Three acquisition times were tested comparatively to a kinetic analysis using MRTM2. Methods: Six healthy volunteers underwent a dynamic SPECT acquisition comprising 14 frames over 28 h and an MR imaging scan. MR images were automatically segmented, providing the volumes of 19 regions of interest (ROIs). SPECT datasets were coregistered with MR images, and regional time–activity curves were derived. For each ROI, a complete MRTM2 pharmacokinetic analysis, using the cerebellar hemispheres as the reference region, led to the calculation of a 123I-iodobenzovesamicol-to-VAChT binding parameter, the nondisplaceable binding potential (BPND-MRTM2). A simplified analysis was also performed at 5, 8, and 28 h after injection, providing a simplified BPND, given as BPND-t = CROI − Ccerebellar hemispheres/Ccerebellar hemispheres, with C being the averaged radioactive concentration. Results: No significant difference was found among BPND-5 h, BPND-8 h, and BPND-MRTM2 in any of the extrastriatal regions explored. BPND-28 h was significantly higher than BPND-5 h, BPND-8 h, and BPND-MRTM2 in 9 of the 17 regions explored (P &lt; 0.05). BPND-5 h, BPND-8 h, and BPND-28 h correlated significantly with BPND-MRTM2 (P &lt; 0.05; ρ = 0.99, 0.98, and 0.92, respectively). In the striatum, BPND-28 h was significantly higher than BPND-5 h and BPND-8 h. BPND-5 h differed significantly from BPND-MRTM2 (P &lt; 0.05), with BPND-5 h being 43.6% lower. Conclusion: In the extrastriatal regions, a single acquisition at 5 or 8 h after injection provides quantitative results similar to a pharmacokinetic analysis. However, with the highest correlation and accuracy, 5 h is the most suitable time to perform an accurate 123I-iodobenzovesamicol quantification. In the striatum, none of the 3 times has led to an accurate quantification.