The influence of motion artifacts conditioned by reconstruction, on the coronary calcium score in multislice spiral CT.

Purpose: A major problem of the quantification of coronary calcifications i s a high variability of the coronary calcium score between recurrent examin ations and different observers. Aim of our study is to evaluate the influen ce of different RR-intervals on the coronary calcium score utilizing retros pectively gated Multislice Spiral CT (MSCT) data sets. Materials and Method : 50 consecutive patients underwent MSCT examination (Somatom Volume Zoom, Siemens, Forchheim, G) utilizing a standardized scan protocol (4 x 2.5 mm c ollimation, 3 mm increment, tube current 133 mAs, tube voltage 120 kV). Ret rospectively gated image reconstruction was performed every 10% of the RR i nterval. Coronary calcification was evaluated by the Agatston score. Corona ry risk assessment was performed in all patients with image reconstruction beginning at 80% of the RR interval. The reconstruction intervals with the least motion artifacts were identified and chosen as reference for a reeval uation of the coronary risk. The results of different reconstruction times were compared. Results: The mean calcium score was 551.6. The calcium score varied between 512.2 (90%) and 571.7 (70%), depending on the image reconst ruction interval. Compared to the mean calcium score a new classification o f the coronary risk was necessary in 7/50 of the patients at 80% reconstruc tion interval, and in 2/50 of the patients at 50% of the RR interval, respe ctively. Conclusion: Movement of the coronary arteries at different image r econstruction intervals has an important influence on the coronary calcium score. Based on our data, we propose image reconstruction at 50% of the RR interval for evaluation of the coronary calcium score by MSCT.