Comparison of 11C-Pittsburgh Compound B and 18F-Flutemetamol White Matter Binding in PET

• Published in: The Journal of nuclear medicine (1978) Vol. 63; no. 8; pp. 1239 - 1244
• Main Authors: Zeydan, Burcu, Schwarz, Christopher G, Przybelski, Scott A, Lesnick, Timothy G, Kremers, Walter K, Senjem, Matthew L, Kantarci, Orhun H, Min, Paul H, Kemp, Bradley J, Jack, Clifford R, Kantarci, Kejal, Lowe, Val J
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.08.2022
• Subjects: Adults; Age; Amyloid; Binding; Cerebellum; Clinical Investigation; Demyelination; Fluorine isotopes; Half-life; Imaging techniques; Integrity; Ligands; Magnetic resonance imaging; Multiple sclerosis; Myelin; Older people; Positron emission; Substantia alba; Tomography; United States > US; Pittsburgh Pennsylvania
• ISSN: 0161-5505; 1535-5667
• DOI: 10.2967/jnumed.121.263281

PET imaging with ß-amyloid ligands is emerging as a molecular imaging technique targeting white matter integrity and demyelination. ß-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 ß-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 < 0.001) and younger (P < 0.001) CU adults. 11C-PiB and 18F-flutemetamol SUVrs were higher in older than in younger CU adults in both WMH (P < 0.001) and NAWM (P < 0.001). 11C-PiB and 18F-flutemetamol SUVrs were higher in NAWM than WMH in both older (P < 0.001) and younger (P < 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.