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medRxiv
MEDRXIV
medRxiv
Cold Spring Harbor Laboratory

10.1101/2024.08.30.24312867
preprint
1
Article
Quantitative Total-Body Imaging of Blood Flow with High Temporal Resolution Early Dynamic 18 F-Fluorodeoxyglucose PET Kinetic Modeling
Chung Kevin J. http://orcid.org/0000-0003-4031-4365

Chaudhari Abhijit J. http://orcid.org/0000-0002-4211-1900

Nardo Lorenzo
Jones Terry
Chen Moon S.
Badawi Ramsey D.
Cherry Simon R.
Wang Guobao
31 8 2024
2024.08.30.24312867https://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which allows reusers to copy and distribute the material in any medium or format in unadapted form only, for noncommercial purposes only, and only so long as attribution is given to the creator.
http://medrxiv.org/lookup/doi/10.1101/2024.08.30.24312867
nihpp-2024.08.30.24312867.pdf
Abstract

Quantitative total-body PET imaging of blood flow can be performed with freely diffusible flow radiotracers such as 15 O-water and 11 C-butanol, but their short half-lives necessitate close access to a cyclotron. Past efforts to measure blood flow with the widely available radiotracer 18 F-fluorodeoxyglucose (FDG) were limited to tissues with high 18 F-FDG extraction fraction. In this study, we developed an early-dynamic 18 F-FDG PET method with high temporal resolution kinetic modeling to assess total-body blood flow based on deriving the vascular transit time of 18 F-FDG and conducted a pilot comparison study against a 11 C-butanol reference.

Methods

The first two minutes of dynamic PET scans were reconstructed at high temporal resolution (60×1 s, 30×2 s) to resolve the rapid passage of the radiotracer through blood vessels. In contrast to existing methods that use blood-to-tissue transport rate (K 1 ) as a surrogate of blood flow, our method directly estimates blood flow using a distributed kinetic model (adiabatic approximation to the tissue homogeneity model; AATH). To validate our 18 F-FDG measurements of blood flow against a flow radiotracer, we analyzed total-body dynamic PET images of six human participants scanned with both 18 F-FDG and 11 C-butanol. An additional thirty-four total-body dynamic 18 F-FDG PET scans of healthy participants were analyzed for comparison against literature blood flow ranges. Regional blood flow was estimated across the body and total-body parametric imaging of blood flow was conducted for visual assessment. AATH and standard compartment model fitting was compared by the Akaike Information Criterion at different temporal resolutions.

Results

18 F-FDG blood flow was in quantitative agreement with flow measured from 11 C-butanol across same-subject regional measurements (Pearson R=0.955, p<0.001; linear regression y=0.973x–0.012), which was visually corroborated by total-body blood flow parametric imaging. Our method resolved a wide range of blood flow values across the body in broad agreement with literature ranges (e.g., healthy cohort average: 0.51±0.12 ml/min/cm 3 in the cerebral cortex and 2.03±0.64 ml/min/cm 3 in the lungs, respectively). High temporal resolution (1 to 2 s) was critical to enabling AATH modeling over standard compartment modeling.

Conclusions

Total-body blood flow imaging was feasible using early-dynamic 18 F-FDG PET with high-temporal resolution kinetic modeling. Combined with standard 18 F-FDG PET methods, this method may enable efficient single-tracer flow-metabolism imaging, with numerous research and clinical applications in oncology, cardiovascular disease, pain medicine, and neuroscience.
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pmc
