Incremental value of ¹⁸F-FDG cardiac PET imaging over dobutamine stress echocardiography in predicting myocardial ischemia in patients with suspected coronary artery disease

Background: To assess the incremental value of ¹⁸F-fluorodeoxyglucose (FDG) cardiac positron emission tomography (PET) over dobutamine stress echocardiography (DSE) in predicting myocardial ischemia in patients with suspected coronary artery disease (CAD).

Methods: Forty-one patients with suspected CAD underwent within 7 days apart rest-stress cardiac PET with ⁸²Rb and DSE followed by cardiac ¹⁸F-FDG PET imaging. ¹⁸F-FDG images were scored on a 0 (no discernible uptake) to 2 (intense uptake) scale. Logistic regression analysis was performed to identify predictors of stress-induced ischemia. The incremental value of ¹⁸F-FDG PET over DSE in detecting ischemia at ⁸²Rb PET cardiac imaging was assessed by the likelihood ratio chi-square and net reclassification index.

Results: On ⁸²Rb-PET imaging, myocardial ischemia (ischemic total perfusion defect ≥ 5%) was detected in 20 (49%) patients. Inducible ischemia was found in 22 (54%) patients on DSE (biphasic or worsening response pattern in ≥ 1 segment) and in 21 (51%) patients on ¹⁸F-FDG PET (uptake score of 2 in ≥ 1 segment). ¹⁸F-FDG PET resulted as statistically significant predictor of ischemia on ⁸²Rb-PET. The addition of ¹⁸F-FDG PET to DSE increased the likelihood of ischemia on ⁸²Rb-PET (P < .05). ¹⁸F-FDG PET was able to reclassify the probability of stress-induced myocardial ischemia on both patient and vessel analyses.

Conclusion: ¹⁸F-FDG PET performed after dobutamine stress test may provide incremental value to DSE in the evaluation of myocardial ischemia. These results suggest that stress-induced myocardial ischemia can be imaged directly using ¹⁸F-FDG PET after dobutamine stress test.