Relationship of coronary calcium and myocardial perfusion in individuals with chest pain

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.

Zusammenfassung

Ziel: Die ergänzende Wertigkeit von Koronarkalk und Myokardperfusion in der Hybrid-PET-CT-Bildegbung ist schlecht definiert. In dieser Studie wurde der Zusammenhang zwischen Koronarkalk, anderen Risikofaktoren und Perfusion in einer Gruppe von Patienten mit Thoraxschmerz und intermediärer Wahrscheinlichkeit für koronare Herzerkrankung definiert. Patienten, Methoden: Bei 70 Patienten wurde unter Verwendungf eines GE Discovery Rx PET-CT Scanners ein Kalzium Score in Ergänzung zu einer Ruhe/Dipyridamol 82Rb PET Perfusionsstudie akquiriert. Summed Stress, Rest und Difference Scores (SSS, SDS, SRS) für die Myokardperfusion wurden anhand eines 20-Segment-Models berechnet. Koronarkalk wurde mittels Agatston-Score und anhand Geschlechts-, Alters- und Rassen-spezifischer Perzentilen (MEAS Datenbank) quantifiziert. Ergebnisse: SSS, SRS und SDS waren abnormal in 25 (36%), 17 (24%) und 12 (17%) Patienten. Agatston-Scores waren 180±446 (0–2122) und Kalkperzentilen waren 42±43% (0–99). Das Agatston Score korrelierte mild aber signifikant mit dem SSS (r=0.31, p=0.01), die Kalkperzentile jedoch nicht. Von 49 Patienten mit normaler Perfusion hatten 25 (57%) ein Kalkscore von 0, und 8 (18%) eine Kalkperzentile >75%. Von 35 Patienten mit einem Kalkscore von 0 hatten 26 (74%) eine normale Myokardperfusion. Patienten bei denen die Krankenaktendurchsicht ein Ereignis in der Nachbeobachtung ergab (n=10) hatten ein signifikant höheres SSS und einen Trend zu einer höheren Kalkperzentile. Schlussfolgerung: Koronarkalk und Myokardperfusion, gemessen in einer einzigen PET-CT Sitzung, zeigen nur eine teilweise übereinstimmung bei Patienten mit Thorxschmerz. Beide Tests scheinen somit verschiedene pathophysiologische Komponenten zu erfassen und scheinen komplementär zur Beschreibung individueller Krankheitsmuster.

Keywords

PET-CT - hybrid imaging - rubidium-82 - coronary calcium - myocardial perfusion

Schlüsselwörter

PET-CT - Hybridbildgebung - Rubidium-82 - Koronarkalk - Myokardperfusion

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