Background: 82 Rb kinetics may distinguish scar from viable but dysfunctional (hibernating) myocardium. We sought to define the relationship between 82 Rb kinetics and myocardial viability compared with conventional 82 Rb and 18 F-fluorodeoxyglucose (FDG) perfusion-metabolism PET imaging. Methods: Consecutive patients (N = 120) referred for evaluation of myocardial viability prior to revascularization and normal volunteers (N = 37) were reviewed. Dynamic 82 Rb 3D PET data were acquired at rest. 18 F-FDG 3D PET data were acquired after metabolic preparation using a standardized hyperinsulinemic-euglycemic clamp. 82 Rb kinetic parameters K 1 , k 2 , and partition coefficient (KP) were estimated by compartmental modeling Results: Segmental 82 Rb k 2 and KP differed significantly between scarred and hibernating segments identified by Rb-FDG perfusion-metabolism (k 2 , 0.42 ± 0.25 vs. 0.22 ± 0.09 min −1 ; P <.0001; KP, 1.33 ± 0.62 vs. 2.25 ± 0.98 ml/g; P <.0001). As compared to Rb-FDG analysis, segmental Rb KP had a c-index, sensitivity and specificity of 0.809, 76% and 84%, respectively, for distinguishing hibernating and scarred segments. Segmental k 2 performed similarly, but with lower specificity (75%, P <.001) Conclusions: In this pilot study, 82 Rb kinetic parameters k 2 and KP, which are readily estimated using a compartmental model commonly used for myocardial blood flow, reliably differentiated hibernating myocardium and scar. Further study is necessary to evaluate their clinical utility for predicting benefit after revascularization.
- cardiac rubidium-82 3D PET
- hibernating myocardium
- Ischemic cardiomyopathy
- kinetic modeling
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Cardiology and Cardiovascular Medicine