J Nucl Cardiol. 2026 Jan;55:102536. doi: 10.1016/j.nuclcard.2025.102536. Epub 2025 Oct 24.
ABSTRACT
BACKGROUND: The clinical significance of single-photon emission computed tomography (SPECT)-derived increase ratio (IR) remains unclear. This study aimed to investigate whether SPECT- IR can diagnose significant coronary artery disease (CAD), correlate with positron emission tomography (PET)-derived myocardial flow reserve (MFR), and predict the composite endpoint.
METHODS: We retrospectively analyzed 60 patients with known or suspected coronary heart disease (CHD) who underwent stress-rest 99mTc-sestamibi myocardial perfusion SPECT and 13N-ammonia PET. Global and regional SPECT-IR and PET-MFR were measured. The endpoint of this study was a composite of all-cause mortality and major adverse cardiovascular events.
RESULTS: Global and regional IR predicted significant CAD, and IR correlated with their respective MFRs (global: r = .43, r2 = .18, P < .001; regional: r = .34, r2 = .12, P < .001). The global IR decreased with advancing CAD severity, as did global MFR. Among nonstenotic vessels, regional IR was significantly lower in patients with MFR <2.0 than in those with MFR ≥2.0. The SPECT-IR may also predict the need for early revascularization as well as PET-MFR. During a median follow-up of 765 days, nine primary events occurred. Using an IR threshold of 1.13, corresponding to an MFR of 2.0, eight of nine patients with events had IR < 1.13. The receiver operating characteristic (ROC) curve analysis of IR showed good predictive ability for adverse events.
CONCLUSION: SPECT-IR is associated with PET-MFR and CAD severity. The SPECT-IR may be a potential predictor of adverse outcomes in patients with known or suspected CHD.
PMID:41591947 | DOI:10.1016/j.nuclcard.2025.102536