Abstract
358
Objectives: Cardiac involvement by sarcoidosis may result in arrhythmias, ventricular dysfunction, and sudden death, and is often unsuspected. We have previously reported preliminary findings with cardiac PET perfusion-metabolic imaging in patients with sarcoidosis. The purpose of this study was to determine the frequency of cardiac perfusion and glucose metabolic abnormalities with PET imaging and relate these abnormalities to extracardiac inflammatory changes and LV function.
Methods: 121 patients (63 women and 58 men, mean age 50 years) with systemic sarcoidosis and suspected cardiac sarcoidosis underwent gated resting and pharmacological stress Rb-82 PET perfusion imaging and glucose-loaded F-18 fluorodeoxyglucose (FDG) PET imaging. Segmental perfusion defects and FDG uptake were graded subjectively on a 4 point and 5 point scale, respectively, in each of 9 myocardial segments. FDG uptake in lymph nodes and pulmonary parenchyma were also graded. Frequency of perfusion defects and myocardial FDG uptake were related to LV function and extracardiac uptake.
Results: Of 121 patients, 34% showed abnormalities in rest perfusion, 42% in stress perfusion, 67% in rest/stress perfusion, with patterns of "scarring" in 31%, "ischemia" in 29%, and "reverse ischemia" in 13%. Increased FDG uptake was seen in 58%, FDG defects in 61%, matched FDG- rest perfusion defects in 25%, mismatched defects in 26%, and reversed mismatched defects in 77%, and LVEF <50% in 27%. 50% of patients had increased extracardiac FDG uptake: 26% in pulmonary parenchyma and 35% in lymph nodes. Cardiac abnormalities were not significantly related to extracardiac FDG uptake. Reduced LVEF was most closely related to perfusion abnormalities at rest and stress, matched or mismatched perfusion-FDG abnormalities, but not to increased FDG uptake.
Conclusions: The majority of patients with systemic sarcoidosis and suspected cardiac involvement had abnormal rest and stress perfusion and FDG metabolic PET studies. The most common cardiac abnormalities were: reverse FDG-rest perfusion mismatched defects, increased FDG (inflammation), rest/stress perfusion defects, usually as "scarring" or "ischemia". Cardiac inflammation was common in, but did not correlate with extracardiac FDG uptake. LVEF was inversely related to stress or rest perfusion defects, or FDG defects, but not inflammation. The prognostic significance of these findings remains to be demonstrated.
- Society of Nuclear Medicine, Inc.