Validation of the calculation of the clearance rate constant (k(mono)) of [(11)C]acetate using parametric k(mono) image for myocardial oxidative metabolism.

INTRODUCTION The purpose of this study was to validate the calculation of myocardial oxidative metabolism rate using a parametric clearance rate constant (k(mono)) image. METHODS Fifteen subjects (seven volunteers, eight patients) were studied. Dynamic PET was acquired after intravenous injection of 700 MBq of [(11)C]acetate. The clearance rate constant of [(11)C]acetate (k(mono)) was calculated pixel by pixel to generate the parametric k(mono) image. The k(mono) values from this image and those calculated from the dynamic image were compared in the same regions of interest (ROIs). RESULTS Two different methods showed an excellent correlation except in the very low range. Regression equations were y=0.99x+0.0034 (r(2)=0.86, P<.001) and y=1.16x-0.0077 (r(2)=0.87, P<.001) in normal volunteer and patient groups, respectively, and y=1.07x-0.0019 (r(2)=0.87, P<.001) when combined. CONCLUSIONS Both methods exhibited similar values of k(mono). Parametric k(mono) image may result in better visual understanding of regional myocardial oxidative metabolism.