Patterns of papillary muscle ischemia in myocardial PET

Purpose: Conventional nuclear medicine equipment lacks sufficient spatial resolution to reliably visualize the papillary muscles (PM). Positron emission tomography (PET), however, can adequately visualize these structures using various positron emitters. Methods and Patients: We present various patterns of PM observed on myocardial PET imaging in 4 patients. These patterns demonstrate different pathologic conditions such as PM ischemia of varying severity, as well as hibernation, using both N-13 NH3 and F-18 FDG as perfusion and metabolic agents, respectively. These patterns of infarction, stress-induced myocardial ischemia, or hibernation can be identified in one or both PM using PET scanning. Normal PM visualization on chest F-18 FDG PET images is also presented. Conclusion: This report illustrates the potential ability of myocardial PET as a noninvasive modality to study the perfusion and metabolic abnormalities of the PM.