Scar imaging using multislice computed tomography versus metabolic imaging by F-18 FDG positron emission tomography:...

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) FDG PET is an established metabolic imaging technique to assess myocardial viability. Delayed iodinated contrast enhancement (DE) of myocardium on computed tomography (CT) has also been shown to be an anatomical marker of nonviable myocardium. A pilot study was undertaken to determine quantitative and qualitative agreement between metabolic viability imaging and scar imaging using FDG PET and multislice CT respectively.

Fifteen patients with coronary artery disease and left ventricular dysfunction were recruited in the study. All patients underwent same day FDG PET and DECT to evaluate myocardial viability. The images were analyzed quantitatively and qualitatively using a 17 segment model.

DECT diagnosed viability in 57% (146/255) whilst PET in 51% (129/255) of segments. The per-segment agreement between DECT and FDG PET on qualitative analysis was 70% (Kappa: 0.40). The agreement in quantitative measurements between the two techniques for viability showed modest correlation [Pearson ρ: 0.63; P<0.0001] on scatter plot and the Passing-Bablok regression analysis. Higher agreement (70 vs 77%; P=0.051; Kappa: 0.40 vs 0.53) was obtained with quantitative compared to qualitative DECT.

DECT may be useful in characterizing myocardial scar, and preliminary results correlate modestly with metabolic FDG PET, both qualitatively and quantitatively. Although in our study quantitative analysis offered superior agreement compared to qualitative with DECT, further studies are needed to determine its incremental value.