Abstract
1870
Objectives To evaluate the role of 18F FDG as a stress ischemia imaging agent.
Methods 33 patients (27 males; mean age 50 yrs) with clinical suspicion of coronary artery disease without history of myocardial infarction were prospectively included in the study. All patients underwent conventional stress rest SPECT MPI with physical stress using tread mill test (TMT) following a one day protocol. Stress FDG imaging was done on another day, within 7 days. All patients underwent coronary angiogram within 30 days of imaging. Suppression of physiological FDG uptake in myocardium was achieved by high fat, high protein, low carbohydrate diet. Blood glucose levels were measured immediately before stress FDG. 5mCi of 18F FDG was injected intravenously at peak stress and gated cardiac PET study was acquired in 3D mode, 60 min later in a hybrid PET CT scanner.
Results 20 patients had history of hypertension, and 3 patients had history of diabetes mellitus. Mean blood glucose level was 107mg% (73-297mg %). All patients had adequate (>7 METS) and similar amount stress in both the PET and SPECT studies. 21 patients had abnormal angiography (at least one coronary artery with >50% stenosis). 13 patients had single vessel, 4 patients each had double and triple vessel disease. When the vascular territories with 50-70% stenosis of coronary artery were analysed the sensitivity of stress FDG and stress MPI was 70% and 17% respectively whereas when vascular territories with >70% stenosis of coronary artery were analysed both stress FDG and stress MPI had a sensitivity of 67%. The sensitivity is significantly higher for stress FDG compared to stress MPI when compared territory wise (Mcnemar p value =0.001) and patient wise (Mcnemar p value <0.05).
Conclusions Stress FDG is as good as stress MPI SPECT in detecting ischemia in patients with >70% stenosis of the coronary artery and has much higher sensitivity than conventional stress MPI in detection of ischemia in patients with 50-70% stenosis