Purpose: Assessing renal perfusion in-vivo is challenging and quantitativeinformation regarding renal hemodynamics is hardly incorporated in medicaldecision-making while abnormal renal hemodynamics... Show morePurpose: Assessing renal perfusion in-vivo is challenging and quantitativeinformation regarding renal hemodynamics is hardly incorporated in medicaldecision-making while abnormal renal hemodynamics might play a crucial rolein the onset and progression of renal disease. Combining physiological stimuliwith rubidium-82 positron emission tomography/computed tomography (82 RbPET/CT) offers opportunities to test the kidney perfusion under various condi-tions. The aim of this study is: (1) to investigate the application of a one-tissuecompartment model for measuring renal hemodynamics with dynamic 82 RbPET/CT imaging, and (2) to evaluate whether dynamic PET/CT is sensitiveto detect differences in renal hemodynamics in stress conditions compared toresting state.Methods: A one-tissue compartment model for the kidney was applied to car-diac 82 Rb PET/CT scans that were obtained for ischemia detection as part ofclinical care. Retrospective data, collected from 17 patients undergoing dynamicmyocardial 82 Rb PET/CT imaging in rest, were used to evaluate various CT-based volumes of interest (VOIs) of the kidney. Subsequently, retrospectivedata, collected from 10 patients (five impaired kidney functions and five controls)undergoing dynamic myocardial 82 Rb PET/CT imaging, were used to evaluateimage-derived input functions (IDIFs), PET-based VOIs of the kidney, extractionfractions, and whether dynamic 82 Rb PET/CT can measure renal hemodynam-ics differences using the renal blood flow (RBF) values in rest and after exposureto adenosine pharmacological stress.Results: The delivery rate (K1 ) values showed no significant (p = 0.14) differ-ence between the mean standard deviation (SD) K1 values using one CT-basedVOI and the use of two, three, and four CT-based VOIs, respectively 2.01(0.32),1.90(0.40), 1.93(0.39), and 1.94(0.40) mL/min/mL. The ratio between RBF inrest and RBF in pharmacological stress for the controls were overall significantlylower compared to the impaired kidney function group for both PET-based delin-eation methods (region growing and iso-contouring), with the smallest medianinterquartile range (IQR) of 0.40(0.28–0.66) and 0.96(0.62–1.15), respectively(p < 0.05). The K1 of the impaired kidney function group were close to1.0 mL/min/mL. Show less
