Impact of SPECT MPI, PET MPI, CCTA and Stress Echo on Downstream Healthcare Utilization in CAD

This large real-world database study used insurance claims data from approximately 2.5 million U.S. patients with coronary artery disease to compare downstream healthcare utilization following four cardiac imaging modalities: SPECT myocardial perfusion imaging (MPI), PET MPI, coronary CT angiography (CCTA), and stress echocardiography.

PET MPI was associated with lower downstream healthcare utilization than SPECT MPI — fewer hospitalizations, fewer invasive coronary angiography procedures, and fewer acute cardiac events following the index test. CCTA and stress echocardiography fell between the two nuclear modalities in most utilization metrics.

The findings are consistent with the known advantages of PET over SPECT: higher spatial resolution, better attenuation correction, and the ability to quantify myocardial flow reserve — reducing the rate of equivocal results that drive downstream testing. A PET result, when clearly positive or clearly negative, is more likely to generate an appropriately definitive clinical pathway than SPECT.

The limitations of a claims-based analysis apply: selection bias is substantial (PET is ordered preferentially in higher-risk or more obese patients), confounding by indication is nearly impossible to fully adjust for, and the database cannot capture imaging quality or physician decision-making.

We rate the evidence moderate. A large real-world study suggesting PET MPI results in more efficient downstream resource use than SPECT — useful for informing imaging selection policy, though subject to claims-data limitations.