PT  - JOURNAL ARTICLE
AU  - Kuwabara, Hiroto
AU  - Comley, Robert A.
AU  - Borroni, Edilio
AU  - Honer, Michael
AU  - Kitmiller, Kelly
AU  - Roberts, Joshua
AU  - Gapasin, Lorena
AU  - Mathur, Anil
AU  - Klein, Gregory
AU  - Wong, Dean F.
TI  - Evaluation of <sup>18</sup>F-RO-948 PET for Quantitative Assessment of Tau Accumulation in the Human Brain
AID  - 10.2967/jnumed.118.214437
DP  - 2018 Dec 01
TA  - Journal of Nuclear Medicine
PG  - 1877--1884
VI  - 59
IP  - 12
4099  - http://jnm.snmjournals.org/content/59/12/1877.short
4100  - http://jnm.snmjournals.org/content/59/12/1877.full
SO  - J Nucl Med2018 Dec 01; 59
AB  - The availability of tau PET radioligands enables quantitative assessment of tau density and distribution in the human brain. We evaluated the kinetics of a novel radioligand, 18F-RO-948 (previously referred to as 18F-RO6958948), and its ability to identify tau positivity in individual patients with mild Alzheimer disease (AD). Methods: Eleven subjects with amyloid-positive mild AD, 5 amyloid-negative older control subjects (OC), and 5 younger control subjects (YC) completed 1 or 2 (4 AD and 5 OC) PET scans with 18F-RO-948 for 90, 120, or 200 min. The kinetics of the radioligand was evaluated with standard compartmental and noncompartmental models (with plasma data in 70% of cases), tissue-reference methods, and SUV ratio. These approaches were applied to assess the ability of 18F-RO-948 to discriminate AD subjects from OC subjects. Results: The plasma reference graphical analysis appeared to be the optimal method of quantification for 18F-RO-948, yielding strictly time-consistent values of distribution volume and distribution volume ratio at 90 min against the analyses at 120 and 200 min. The reference tissue graphical analysis and SUV ratio were cross-validated against plasma reference graphical analysis. Test–retest evaluation showed excellent reproducibility. A proposed novel index of tau load, the regional tau-positive fraction, showed high values in the medial and lateral temporal and parietal regions in AD and successfully separated AD subjects from OC and YC subjects with a significant margin. Conclusion: 18F-RO-948 appears to be a promising radioligand for quantitative imaging of tau in the brain of AD patients.