Improved Performance of PET Myocardial Perfusion Imaging Compared to SPECT in the Evaluation of Suspected CAD

When a doctor wants to see whether the heart muscle is getting enough blood, the long-standing workhorse has been SPECT imaging. This review makes the case that its newer sibling, PET, simply does the job better — and asks why adoption lags.

Comparing the two myocardial perfusion techniques across the literature, the authors find PET ahead on most axes that matter: sharper diagnostic accuracy, better image quality, shorter scan protocols, and lower radiation exposure. PET’s particular edge is quantitative — it can measure absolute myocardial blood flow, which lets it detect not only the classic obstructed artery but the diffuse microvascular disease that SPECT tends to miss entirely.

The practical implication is straightforward where PET is available: more accurate diagnosis and cleaner risk stratification in people with suspected coronary disease. The obstacle is just as practical — many centers are heavily invested in SPECT equipment and expertise, and PET scanners are costlier and scarcer, which is where the resistance to switching lives.

We rate the evidence moderate. This is a well-referenced review — 88 citations — but a narrative one, summarizing a growing consensus rather than generating new data. Its clinical significance is similarly moderate: the advantages are real and the microvascular insight genuinely useful, but limited availability and higher cost keep PET from being the default for now. The direction of travel is clear; the infrastructure simply hasn’t caught up.