Comparison of Coronary CT Angiography, SPECT, PET, and Hybrid Imaging for Diagnosis of Ischemic Heart Disease Determined by Fractional Flow Reserve

Abstract

Importance

At present, the choice of noninvasive testing for a diagnosis of significant coronary artery disease (CAD) is ambiguous, but nuclear myocardial perfusion imaging with single-photon emission tomography (SPECT) or positron emission tomography (PET) and coronary computed tomography angiography (CCTA) is predominantly used for this purpose. However, to date, prospective head-to-head studies are lacking regarding the diagnostic accuracy of these imaging modalities. Furthermore, the combination of anatomical and functional assessments configuring a hybrid approach may yield improved accuracy.

Objectives

To establish the diagnostic accuracy of CCTA, SPECT, and PET and explore the incremental value of hybrid imaging compared with fractional flow reserve.

Design, Setting, and Participants

A prospective clinical study involving 208 patients with suspected CAD who underwent CCTA, technetium 99m/tetrofosmin–labeled SPECT, and [ ¹⁵O]H ₂O PET with examination of all coronary arteries by fractional flow reserve was performed from January 23, 2012, to October 25, 2014. Scans were interpreted by core laboratories on an intention-to-diagnose basis. Hybrid images were generated in case of abnormal noninvasive anatomical or functional test results.

Main Outcomes and Measures

Hemodynamically significant stenosis in at least 1 coronary artery as indicated by a fractional flow reserve of 0.80 or less and relative diagnostic accuracy of SPECT, PET, and CCTA in detecting hemodynamically significant CAD.

Results

Of the 208 patients in the study (76 women and 132 men; mean [SD] age, 58 [9] years), 92 (44.2%) had significant CAD (fractional flow reserve ≤0.80). Sensitivity was 90% (95% CI, 82%-95%) for CCTA, 57% (95% CI, 46%-67%) for SPECT, and 87% (95% CI, 78%-93%) for PET, whereas specificity was 60% (95% CI, 51%-69%) for CCTA, 94% (95% CI, 88%-98%) for SPECT, and 84% (95% CI, 75%-89%) for PET. Single-photon emission tomography was found to be noninferior to PET in terms of specificity ( P < .001) but not in terms of sensitivity ( P > .99) using the predefined absolute margin of 10%. Diagnostic accuracy was highest for PET (85%; 95% CI, 80%-90%) compared with that of CCTA (74%; 95% CI, 67%-79%; P = .003) and SPECT (77%; 95% CI, 71%-83%; P = .02). Diagnostic accuracy was not enhanced by either hybrid SPECT and CCTA (76%; 95% CI, 70%-82%; P = .75) or by PET and CCTA (84%; 95% CI, 79%-89%; P = .82), but resulted in an increase in specificity ( P = .004) at the cost of a decrease in sensitivity ( P = .001).

Conclusions and Relevance

This controlled clinical head-to-head comparative study revealed PET to exhibit the highest accuracy for diagnosis of myocardial ischemia. Furthermore, a combined anatomical and functional assessment does not add incremental diagnostic value but guides clinical decision-making in an unsalutary fashion.

Abstract

This head-to-head comparative study evaluates the diagnostic accuracy of coronary computed tomography angiography, single-photon emission tomography, and positron emission tomography and explores the incremental value of hybrid imaging compared with fractional flow reserve.

Key Points

Question

What are the diagnostic performances of coronary computed tomography angiography, single-photon emission tomography, [ ¹⁵O]H ₂O positron emission tomography, and hybrid imaging for the diagnosis of myocardial ischemia using fractional flow reserve as a reference standard?

Findings

In this head-to-head comparative study of 208 adults, sensitivity was 90% for coronary computed tomography angiography, 57% for single-photon emission tomography, and 87% for positron emission tomography, whereas specificity was 60% for coronary computed tomography angiography, 94% for single-photon emission tomography, and 84% for positron emission tomography. Positron emission tomography exhibited the highest diagnostic accuracy compared with single-photon emission tomography and coronary computed tomography angiography.

Meaning

Coronary computed tomography angiography and [ ¹⁵O]H ₂O positron emission tomography are both useful in the diagnosis of myocardial ischemia, while single-photon emission tomography and hybrid imaging guide clinical decision making in an unsalutary fashion.