Myocardial CT perfusion imaging outperforms SPECT in CAD diagnosis

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Myocardial CT perfusion imaging performed higher than SPECT in the diagnosis of anatomic coronary artery disease (CAD), according to a study published online May 26 by Radiology.

As myocardial CT perfusion imaging has developed, research has demonstrated its potential in accurately diagnosing CAD in comparison with a variety of reference standards. Lead author Richard T. George, MD, of Johns Hopkins University in Baltimore, and colleagues conducted a prespecified, secondary analysis of the multicenter diagnostic accuracy study, Combined Coronary Atherosclerosis and Myocardial Perfusion Evaluation Using 320-Detector Row CT (CORE320), to compare the diagnostic performance of CT perfusion imaging and SPECT perfusion imaging in the diagnosis of anatomic CAD as depicted at invasive coronary angiography.

The study included 381 patients who enrolled in 16 centers between November 2009 and July 2011. The patients underwent rest and adenosine stress CT perfusion imaging, rest, and either exercise or pharmacologic stress SPECT before and within 60 days of coronary angiography. The images from CT perfusion imaging, SPECT, and coronary angiography were interpreted at blinded, independent core laboratories. Using a 13-segment myocardial model, the two observers scored rest and stress myocardial segments on a scale of zero to three. The reference standard was a stenosis of at least 50 percent at coronary angiography, as determined using quantitative methods.

CAD was diagnosed in 60 percent, or 229 of the 381 patients. The per-patient sensitivity and specificity for the diagnosis of CAD were 88 percent and 55 percent for CT perfusion imaging and 62 percent and 67 percent for SPECT. The area under the receiver operating characteristic curve was 0.78 for CT perfusion imaging and 0.69 for SPECT.

For perfusion imaging, the sensitivity for single and multivessel CAD for left main, three-vessel, two-vessel, and one-vessel disease was 92 percent, 92 percent, 89 percent and 83 percent, respectively. In comparison, the sensitivity for SPECT was respectively 75 percent, 79 percent, 68 percent and 41 percent.

“This study demonstrates that CT perfusion imaging is a viable alternative to SPECT myocardial perfusion imaging for the detection of CAD,” wrote George and colleagues. “CT perfusion imaging maintains sensitivity for detecting coronary disease in patients with left main and multivessel disease.”