The relationship between stress-induced myocardial ischemia and coronary artery atherosclerosis measured by hybrid SPECT/CT camera.

OBJECTIVE

The coronary artery calcium (CAC) score and myocardial perfusion imaging can now be detected simultaneously using a hybrid SPECT/CT camera. However, there has been little evaluation on the relationship between stress-induced ischemia and coronary artery calcification in a Japanese population. The aim of this study was to investigate the relationship between these parameters and to elucidate the diagnostic value of the CAC score as an adjunct to myocardial perfusion imaging (MPI) for the assessment of coronary artery disease (CAD) in an intermediate-risk population.

METHODS

We retrospectively analyzed 105 patients (63% men, mean age 71 years) with CAD or suspected CAD who underwent MPI using SPECT/CT. CAC scanning was performed using a SPECT/CT camera.

RESULTS

There was a significant difference in the CAC score between patients with ischemia (n = 42) and those without ischemia (n = 63) (1353 ± 1524 vs. 332 ± 554, p < 0.01). The frequency of ischemic MPI determined by summed difference score tended to be higher in patients with high CAC (CAC = 0; 0.8 ± 1.3 vs. CAC > 1000; 3.0 ± 2.0). Higher age is related roughly with higher CAC score with no statistical significance (r(2) = 0.1) (<60 years old; 200 ± 692, vs. >80 years old; 1258 ± 1546, ns). The location of calcification was not related to the ischemic area. In a population with a predominately intermediate likelihood of CAD, a calcium score of zero has a possibility of excluding inducible ischemia on MPI. In part, ischemic MPI is associated with a high likelihood of subclinical atherosclerosis as detected by CAC.

CONCLUSION

Hybrid SPECT/CT might be useful for diagnostic assessment and coronary artery with known or suspected CAD.