PT - JOURNAL ARTICLE AU - Burcu Zeydan AU - Christopher G. Schwarz AU - Scott A. Przybelski AU - Timothy G. Lesnick AU - Walter K. Kremers AU - Matthew L. Senjem AU - Orhun H. Kantarci AU - Paul H. Min AU - Bradley J. Kemp AU - Clifford R. Jack, Jr. AU - Kejal Kantarci AU - Val J. Lowe TI - Comparison of <sup>11</sup>C-Pittsburgh Compound B and <sup>18</sup>F-Flutemetamol White Matter Binding in PET AID - 10.2967/jnumed.121.263281 DP - 2022 Aug 01 TA - Journal of Nuclear Medicine PG - 1239--1244 VI - 63 IP - 8 4099 - http://jnm.snmjournals.org/content/63/8/1239.short 4100 - http://jnm.snmjournals.org/content/63/8/1239.full SO - J Nucl Med2022 Aug 01; 63 AB - PET imaging with β-amyloid ligands is emerging as a molecular imaging technique targeting white matter integrity and demyelination. β-amyloid PET ligands such as 11C-Pittsburgh compound B (11C-PiB) have been considered for quantitative measurement of myelin content changes in multiple sclerosis, but 11C-PiB is not commercially available given its short half-life. A 18F PET ligand such as flutemetamol with a longer half-life may be an alternative, but its ability to differentiate white matter hyperintensities (WMH) from normal-appearing white matter (NAWM) and its relationship with age remains to be investigated. Methods: Cognitively unimpaired (CU) older and younger adults (n = 61) were recruited from the community responding to a study advertisement for β-amyloid PET. Participants prospectively underwent MRI, 11C-PiB, and 18F-flutemetamol PET scans. MRI fluid-attenuated inversion recovery images were segmented into WMH and NAWM and registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol PET images were also registered to the T1-weighted MRI. 11C-PiB and 18F-flutemetamol SUV ratios (SUVrs) from the WMH and NAWM were calculated using cerebellar crus uptake as a reference for both 11C-PiB and 18F-flutemetamol. Results: The median age was 38 y (range, 30–48 y) in younger adults and 67 y (range, 61–83 y) in older adults. WMH and NAWM SUVrs were higher with 18F-flutemetamol than with 11C-PiB in both older (P &lt; 0.001) and younger (P &lt; 0.001) CU adults. 11C-PiB and 18F-flutemetamol SUVrs were higher in older than in younger CU adults in both WMH (P &lt; 0.001) and NAWM (P &lt; 0.001). 11C-PiB and 18F-flutemetamol SUVrs were higher in NAWM than WMH in both older (P &lt; 0.001) and younger (P &lt; 0.001) CU adults. There was no apparent difference between 11C-PiB and 18F-flutemetamol SUVrs in differentiating WMH from NAWM in older and in younger adults. Conclusion: 11C-PiB and 18F-flutemetamol show a similar topographic pattern of uptake in white matter with a similar association with age in WMH and NAWM. 11C-PiB and 18F-flutemetamol can also effectively distinguish between WMH and NAWM. However, given its longer half-life, commercial availability, and higher binding potential, 18F-flutemetamol can be an alternative to 11C-PiB in molecular imaging studies specifically targeting multiple sclerosis to evaluate white matter integrity.