Abstract
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Objectives Determine optimal cut-off values for absolute myocardial blood flow (MBF) and to evaluate the diagnostic accuracy of quantitative [15O]H2O PET
Methods A total of 330 patients without a previous cardiac history underwent both quantitative [15O]H2O PET imaging and invasive coronary angiography in conjunction with fractional flow reserve (FFR) measurements. A stenosis > 90% and/or an FFR ≤ 0.80 was considered obstructive, while a stenosis < 30% and/or an FFR > 0.80 was considered non-obstructive.
Results Hemodynamic significant coronary artery disease (CAD) was diagnosed in 116 (41%) out of 281 patients. Resting MBF was 1.00 ± 0.26 and 0.92 ± 0.23 mL/min/g in regions supplied by non-stenosed and significantly stenosed vessels, respectively (p < 0.001). Hyperemic MBF was 3.26 ± 1.05 and 1.78 ± 0.74 mL/min/g, respectively (p<0.001). The optimal hyperemic MBF cut-off value was 2.3 mL/min/g and 2.5 for myocardial flow reserve (MFR). With these cut-off values, sensitivity, specificity and accuracy of hyperemic MBF for the detection of functionally relevant CAD were 87, 84, and 85%, respectively at a per patient analysis and 85, 83 and 84% at a per vessel based analysis. The corresponding values for MFR were 84, 73 and 77% at a per patient level and 79, 80 and 80% at a per vessel level. In addition, gender and age exerted a significant impact on the diagnostic accuracy of quantitative PET.
Conclusions The optimal cut-off values for detecting flow limiting CAD were 2.3 mL/min/g and 2.5 for hyperemic MBF and MFR, respectively. Hyperemic MBF was superior to MFR for diagnosing hemodynamically significant CAD. Absolute MBF measurements provide high diagnostic performance, but both gender and age should be taken into account.