PT  - JOURNAL ARTICLE
AU  - Young, Juan J.
AU  - O’Dell, Ryan S.
AU  - Naganawa, Mika
AU  - Toyonaga, Takuya
AU  - Chen, Ming-Kai
AU  - Nabulsi, Nabeel B.
AU  - Huang, Yiyun
AU  - Cooper, Emma
AU  - Miller, Alyssa
AU  - Lam, Jessica
AU  - Bates, Kara
AU  - Ruan, Audrey
AU  - Nelsen, Kimberly
AU  - Salardini, Elaheh
AU  - Carson, Richard E.
AU  - van Dyck, Christopher H.
AU  - Mecca, Adam P.
TI  - Validation of a Simplified Tissue-to-Reference Ratio Measurement Using SUVR to Assess Synaptic Density Alterations in Alzheimer Disease with [<sup>11</sup>C]UCB-J PET
AID  - 10.2967/jnumed.124.267419
DP  - 2024 Sep 19
TA  - Journal of Nuclear Medicine
PG  - jnumed.124.267419
4099  - http://jnm.snmjournals.org/content/early/2024/09/19/jnumed.124.267419.short
4100  - http://jnm.snmjournals.org/content/early/2024/09/19/jnumed.124.267419.full
AB  - Simplified methods of acquisition and quantification would facilitate the use of synaptic density imaging in multicenter and longitudinal studies of Alzheimer disease (AD). We validated a simplified tissue-to-reference ratio method using SUV ratios (SUVRs) for estimating synaptic density with [11C]UCB-J PET. Methods: Participants included 31 older adults with AD and 16 with normal cognition. The distribution volume ratio (DVR) using simplified reference tissue model 2 was compared with SUVR at short scan windows using a whole-cerebellum reference region. Results: Synaptic density was reduced in AD participants using DVR or SUVR. SUVR using later scan windows (60–90 or 70–90 min) was minimally biased, with the strongest correlation with DVR. Effect sizes using SUVR at these late time windows were minimally reduced compared with effect sizes with DVR. Conclusion: A simplified tissue-to-reference method may be useful for multicenter and longitudinal studies seeking to measure synaptic density in AD.