Relative Flow Reserve Derived From Quantitative Perfusion Imaging May Not Outperform Stress Myocardial Blood Flow for Identification of Hemodynamically Significant XXXX .

@entity1 @entity296 @entity1009 @entity26 @entity453
BACKGROUND: Quantitative myocardial perfusion imaging is increasingly used for the diagnosis of @entity453 . Quantitative perfusion imaging allows to noninvasively calculate fractional flow reserve (FFR). This so-called relative flow reserve (RFR) is defined as the ratio of @entity296 flow ( @entity296 ) in a stenotic area to hyperemic @entity296 in a normal perfused area. The aim of this study was to assess the value of RFR in the detection of significant @entity453 . METHODS AND RESULTS: From a clinical population of @entity1 with suspected @entity453 who underwent @entity26 -15-labeled water cardiac positron emission tomography and invasive coronary angiography, 92 @entity1 with single- or 2-vessel disease were included. Intermediate lesions (diameter stenosis, 30%-90%; n=75) were interrogated by FFR. Thirty-eight (41%) vessels were deemed hemodynamically significant (>90% stenosis or FFR  <=0.80). Hyperemic @entity296 , coronary flow reserve, and RFR were lower for vessels with a hemodynamically significant lesion (2.01  0.78 versus 2.90  1.16 mL  @entity1009 )  g(-1); P<0.001, 2.27  1.03 versus 3.10  1.29; P<0.001, and 0.67  0.23 versus 0.93  0.15; P<0.001, respectively). The correlation between RFR and FFR was moderate (r=0.54; P<0.01). Receiver operator characteristic curve analysis showed an area under the curve of 0.82 for RFR, which was not significantly higher compared with that for hyperemic @entity296 and coronary flow reserve (0.76; P=0.32 and 0.72; P=0.08, respectively). CONCLUSIONS: Noninvasive estimation of FFR by quantitative perfusion positron emission tomography by calculating RFR is feasible, yet only a trend toward a slight improvement of diagnostic accuracy compared with hyperemic @entity296 assessment was determined.
