Fig. 1
Final Software Processing of 2-[18F]FDG Myocardial uptake analysis. Top panel: short-axis, horizontal long-axis and vertical long-axis images from 2-[18F]FDG PET/CT with LV volume of interest (VOI) superimposed as defined in the perfusion PET. A VOI in the LV cavity was drawn to determine blood pool activity. The 2-[18F]FDG threshold was calculated as the blood pool activity (SUV mean) multiplied by a factor of 1.1. Middle panel: Left: Rest [13N]NH3 perfusion polar plots. The first plot shows average perfusion, percentage wise, per region. The blackout areas in the second plot indicate abnormally low perfusion. Right: 2-[18F]FDG uptake (metabolism) polar plots. The third plot indicates the average SUV for each region. The black areas in the fourth plot indicate abnormally high 2-[18F]FDG uptake (SUV exceeds the threshold). Bottom panel: Integration of the rest [13N]NH3 perfusion and 2-[18F]FDG myocardial uptake analysis identifies distinct patterns: Scar (green): Reduced perfusion and no significant 2-[18F]FDG uptake (referred to, in the text, as fibrosis). Inflammatory myocardium (blue): Normal perfusion and increased 2-[18F]FDG uptake (referred to, in the text, as hypermetabolic myocardium). These patterns are expressed as percentages of the total left ventricle and further categorized according to five regions: apex, septum, anterior wall, inferior wall, and lateral wall. In the example provided, the patient exhibited 33% normal myocardium, 46% inflammatory (hypermetabolic) myocardium and 3% scar (fibrosis) extension.
