Simplified Quantification of ¹¹C-UCB-J PET Evaluated in a Large Human Cohort.

Abstract

¹¹C-UCB-J ((<i>R</i>)-1-((3-(¹¹C-methyl-¹¹C)pyridin-4-yl)methyl)-4-(3,4,5-trifluorophenyl)pyrrolidin-2-one) is a PET tracer for synaptic vesicle glycoprotein 2A, which may be a marker of synaptic density. To simplify the scan protocol, SUV ratios (SUVRs) were compared with model-based nondisplaceable binding potential (<i>BP</i>_ND) to select the optimal time window in healthy and neuropsychiatric subjects. <b>Methods:</b> In total, 141 scans were acquired for 90 min. Arterial blood sampling and metabolite analysis were conducted. SUVR-1 (centrum semiovale reference region) was computed for six 30-min windows and compared with 1-tissue-compartment model <i>BP</i>_ND Simulations were performed to assess the time dependency of SUVR-1. <b>Results:</b> Greater correlation and less bias were observed for SUVR-1 at later time windows for all subjects. Simulations showed that the agreement between SUVR-1 and <i>BP</i>_ND is time-dependent. <b>Conclusion:</b> The 60- to 90-min period provided the best match between SUVR-1 and <i>BP</i>_ND (-1% ± 7%); thus, a short scan is sufficient for accurate quantification of ¹¹C-UCB-J-specific binding.