Relative 11C-PiB Delivery as a Proxy of Relative CBF: Quantitative Evaluation Using Single-Session 15O-Water and 11C-PiB PET

Y. J. Chen, B. L. Rosario, W. Mowrey, C. M. Laymon, X. Lu, O. L. Lopez, W. E. Klunk, B. J. Lopresti, C. A. Mathis, J. C. Price
2015 Journal of Nuclear Medicine  
The primary goal of this study was to assess the suitability of 11 C-Pittsburgh compound B ( 11 C-PiB) blood-brain barrier delivery (K 1 ) and relative delivery (R 1 ) parameters as surrogate indices of cerebral blood flow (CBF), with a secondary goal of directly examining the extent to which simplified uptake measures of 11 C-PiB retention (amyloid-b load) may be influenced by CBF, in a cohort of controls and patients with mild cognitive impairment (MCI) and Alzheimer disease (AD). Methods:
more » ... eteen participants (6 controls, 5 AD, 8 MCI) underwent MR imaging, 15 O-water PET, and 11 C-PiB PET in a single session. Fourteen regions of interest (including cerebellar reference region) were defined on MR imaging and applied to dynamic coregistered PET to generate time-activity curves. Multiple analysis approaches provided regional 15 O-water and 11 C-PiB measures of delivery and 11 C-PiB retention that included compartmental modeling distribution volume ratio (DVR), arterial-and reference-based Logan DVR, simplified reference tissue modeling 2 (SRTM2) DVR, and standardized uptake value ratios. Spearman correlation was performed among delivery measures (i.e., 15 O-water K 1 and 11 C-PiB K 1 , relative K 1 normalized to cerebellum [Rel-K 1-Water and Rel-K 1-PiB ], and 11 C-PiB SRTM2-R 1 ) and between delivery measures and 11 C-PiB retention, using the Bonferroni method for multiple-comparison correction. Results: Primary analysis showed positive correlations (r ≈0.2-0.5) between 15 O-water K 1 and 11 C-PiB K 1 that did not survive Bonferroni adjustment. Significant positive correlations were found between Rel-K 1-Water and Rel-K 1-PiB and between Rel-K 1-Water and 11 C-PiB SRTM2-R 1 (r ≈0.5-0.8, P , 0.0036) across primary cortical regions. Secondary analysis showed few significant correlations between 11 C-PiB retention and relative 11 C-PiB delivery measures (but not 15 O-water delivery measures) in primary cortical areas that arose only after accounting for cerebrospinal fluid dilution. Conclusion: 11 C-PiB SRTM2-R 1 is highly correlated with regional relative CBF, as measured by 15 O-water K 1 normalized to cerebellum, and cross-sectional 11 C-PiB retention did not strongly depend on CBF across primary cortical regions. These results provide further support for potential dual-imaging assessments of regional brain status (i.e., amyloid-b load and relative CBF) through dynamic 11 C-PiB imaging.
doi:10.2967/jnumed.114.152405 pmid:26045309 pmcid:PMC4730871 fatcat:z2yong35bvh3rauuik2pzxozii