Previous studies results were unclear whether myocardial flow reserve (MFR) derived from dynamic perfusion SPECT using the novel SPECT camera (D-SPECT) reflects the severity of coronary atherosclerosis. In the present study, we, therefore, examined the relationship between MFR using D-SPECT and severity of coronary lesions 

Myocardial perfusion imaging is the standard method for evaluating myocardial ischemia in patients with coronary artery disease (CAD). However, ischemia is generally diagnosed by visual evaluation rather than quantitatively.

Further, extensive ischemia with the multi-vessel disease is typically difficult to diagnose using relative evaluation with myocardial single-photon emission computed tomography (SPECT) [4], indicating the importance of developing new methods to quantitatively evaluate coronary circulation.

The study population comprised 40 patients who underwent both a myocardial dynamic perfusion SPECT study and invasive coronary angiography. The severity of coronary atherosclerosis was evaluated using the Gensini score.

Results

All patients underwent a rest/stress SPECT imaging protocol using Tc-99m-sestamibi, and the dynamic acquisition was performed. Stress and rest flow were evaluated, and the global and regional MFR was calculated.

Global MFR showed a significant negative correlation with Gensini score (r = – 0.345, p = 0.037). Multiple linear regression analysis showed that only global MFR was independently related to Gensini score (p = 0.018).

They demonstrated that measurement of global MFR using a novel SPECT camera is useful for assessing global coronary atherosclerosis and that reduced regional MFR suggests the existence of severe coronary stenotic lesions.

Given that SPECT examination is globally established, measurement of MFR by D-SPECT may be particularly useful in the clinic to provide improved prognostic value and decision-making for coronary angioplasty in patients with ischemic heart disease.

Regional MFR was significantly lower in regions with 90% ≤ stenotic lesions compared with regions with < 90% stenotic lesions (p = 0.009). Global MFR derived by dynamic perfusion SPECT using D-SPECT reflects the severity of coronary atherosclerosis. Further, regional MFR is modulated by severe coronary artery stenotic lesions.