Summary

Aim: The integrated value of coronary calcium scoring added to myocardial perfusion assessment in hybrid PETCT imaging remains poorly defined. In the present study, we sought to determine the relationship between calcium burden, other risk factors, and tissue perfusion in a group of patients with chest pain and predominantly intermediate likelihood for coronary artery disease. Patients, methods: In 70 patients, coronary calcium scores (CCS) were obtained in addition to rest/dipyridamole stress 82Rb perfusion images using a GE Discovery Rx hybrid PET-CT system. From static perfusion images, summed rest, stress and difference scores (SRS, SSS, SDS) were calculated using a 20-segment model. Absolute CCS was determined according to Agatston and age-, gender-, and ethnicity-matched CCS percentiles were calculated using the MESA database. Results: SSS, SRS and SDS were abnormal (≥4) in 25 (36%), 17 (24%), and 12 (17%) patients. Mean CCS according to Agatston was 180 ± 446(range 0–2122), and CCS percentile was 42 ± 43(range 0–99). Absolute CCS correlated mildly but significantly with SSS (r = 0.31, p = 0.01), while CCS percentile did not (r = 0.11, p = 0.36). Of 49 patients with normal perfusion, 25 (57%) had CCS = 0, and 8 (18%) had a CCS percentile ≥75th. Of 35 patients with a CCS = 0, 26 (74%) had normal perfusion. Individuals in whom review of patient records revealed events during follow-up (n = 10) had significantly higher SSS than those where no events were recorded (6.0 ± 7.2 versus 2.9 ± 3.1, p = 0.03), and there was a trend towards higher CCS percentiles (62 ± 36 versus 35 ± 43, p = 0.06). Conclusion: Coronary calcifications and myocardial tissue perfusion, as interrogated in a single PET-CT imaging session, show only partial agreement in patients with chest pain. Both tests seem to reflect different pathophysiologic components, and may be complementary for definition of individual disease patterns.