Positron Emission Tomography Offers Diagnostic Value in Myocardial Ischemia

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Researchers compared the diagnostic accuracy of imaging modalities for coronary artery disease diagnosis.
Researchers compared the diagnostic accuracy of imaging modalities for coronary artery disease diagnosis.

Positron emission tomography (PET) offers the greatest diagnostic accuracy for myocardial ischemia when compared with coronary computed tomography angiography (CCTA) and single-photon emission tomography (SPECT), according to a controlled prospective clinical study published in JAMA Cardiology.

Investigators compared imaging modalities with respect to specificity, sensitivity, positive and negative predictive values, and accuracy for the identification of hemodynamically significant coronary artery disease (CAD).

Significant CAD with a fractional flow reserve of ≤0.80 was present in 92 patients (44.2%). Investigators found that sensitivity for CCTA, PET, and SPECT was 90% (95% CI, 82%-95%), 87% (95% CI, 78%-93%), and 57% (95% CI, 46%-67%), respectively.

In addition, specificity was 60% (95% CI, 51%-69%) for CCTA, 84% (95% CI, 75%-89%) for PET, and 94% (95% CI, 88%-98%) for SPECT. Using the noninferiority margin of 10%, the researchers determined that the specificity of SPECT was noninferior to PET (94%; P <.001). SPECT was not found to be noninferior to PET with regard to sensitivity (57%; P >.99).

Overall, PET demonstrated a higher diagnostic accuracy (85%; 95% CI, 80%-90%) compared with SPECT (77%; 95% CI, 71%-83%; P =.02) and CCTA (74%; 95% CI, 67%-79%; P =.003). No significant enhancement in diagnostic accuracy was observed with either hybrid PET and CCTA (84%; 95% CI, 79%-89%; P =.82) or hybrid SPECT and CCTA (76%; 95% CI, 70%-82%; P =.75).

The investigators noted that the results of this study should be interpreted with respect to this particular population; however, their findings may be applicable to patients at low risk for CAD who do not necessarily require a test with high specificity.

Hybrid imaging methods did appear to improve diagnostic accuracy, suggesting "widespread use of CCTA coupled with SPECT or PET will result in increased radiation exposure to the patient and may mitigate its utility in a clinical setting," the researchers concluded.

Reference

Danad I, Raijmakers PG, Driessen RS, et al. Comparison of coronary CT angiography, SPECT, PET, and hybrid imaging for diagnosis of ischemic heart disease determined by fractional flow reserve. JAMA Cardiol [published online August 16, 2017]. doi:10.1001/jamacardio.2017.2471

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