Measuring hypoxia in chronic limb-threatening ischemia using 18F-FAZA kinetic modelling - a pilot study.

Background: Chronic limb- threatening ischemia (CLTI) is a serious condition that can lead to amputation, and in some cases, it can be associated with mortality. Current clinical evaluation methods have several limitations. Therefore, new methods to assess CLTI are needed to better understand and measure underlying causes and functionality, and hence potentially improve the treatment. In this study, we use dynamic ¹⁸F-FAZA PET-imaging as a method of measuring hypoxia as a marker associated with CLTI, on twelve patients identified with CLTI who underwent ¹⁸F-FAZA PET-MR imaging.

Results: The kinetic modelling goodness-of-fit metrics using AIF from independent limb with the irreversible-2TC3K model distinguished between index and contralateral limbs better than the reversable-2TC4K model. The Spearman correlation coefficients between the standardized uptake value (SUV) SUV-to-SUV_med ratio and the perfusion parameter, [Formula: see text], was r_s = -0.07 for index and r_s = 0.22 for contralateral limbs. For the SUV-to-SUV_med ratio correlation with diffusion parameter, [Formula: see text], it is found to be negative for both index (r_s = -0.16) and contralateral (r_s = -0.11).

Conclusions: The kinetic modelling of ¹⁸F-FAZA dynamic PET-MR was able to differentiate between index and contralateral limbs in CLTI patients, and the diffusion metric from the kinetic modelling can potentially be used as a metric to measure hypoxia in CLTI.

Trial registration: ClinicalTrials.gov, NCT04054609. Registered 20,190,611, https//clinicaltrials.gov/study/NCT04054609.