RESUMO
AIM: The integrated value of coronary calcium scoring added to myocardial perfusion assessment in hybrid PET-CT 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 (>or=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>or=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.
