Bildqualität von CT-Angiografien der Koronararterien in Abhängigkeit vom Ausmaß der Koronarverkalkungen bei Einsatz eines Dual-Source-CTs

PURPOSE: To evaluate the influence of severe calcification on image quality of CT angiography (CTA) of coronary arteries acquired with dual source CT. METHOD: 171 dual source CTAs in spiral mode were evaluated. Depending on the Agatston score (CS), patients where divided into four subgroups (I: CS 0 - 200, II: CS 201 - 600, III: CS 601 - 1000, IV: CS > 1000). Image quality was evaluated by two independent, blinded readers using a three-stage scale and the image quality of each subgroup was also shown with the help of an image quality index (BQI). In addition, a comparison with coronary catheter angiography was undertaken in a subgroup. RESULTS: Dual source CTA in spiral mode showed good image quality even in patients with Agatston scores of 601 - 1000 and > 1000. The four classes showed no significant difference in image quality. (BQI = 1,164 [I], BQI = 1,212 [II], BQI = 1,281 [III], BQI = 1,111 [IV]; p = 0,3145). The detailed analysis showed particularly good quality in patients with a heart rate 200 and heart rates > 75 bpm showed a statistically significant reduction in image quality (BQI = 1,625; p = 0,0016). There were no gender differences in the image quality (p = 0,9881) although the calcium scores differed significantly in men (CS = 313 [± 449]) and women (CS = 145 [± 304]). The comparison with coronary catheter angiography showed a good correlation (92 %). CONCLUSION: CTA of coronary arteries performed with dual source CT in spiral mode provides good image quality even in patients with higher calcification scores. The reduction of heart rates > 75 bpm improves the image quality significantly in patients with higher calcification scores.