Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients.

The aim of our study was to evaluate attenuation-based tube current adaptation in coronary calcium scoring using ECG-gated multi-detector-row CT (MDCT). A total of 262 patients underwent non-enhanced cardiac MDCT. Group 1 was scanned using a standard protocol with 120 kV and 150 mAs(eff). Groups 2-4 were scanned using an attenuation-based dose-adaptation template (CARE Dose) with different effective reference mAs settings (150, 180, 210 mAs(eff)). Body-mass index (BMI) and CT-dose index values were calculated for each patient. Image noise and subjective image quality were assessed. Regression analysis was performed, and the variation coefficient of image noise was determined. Compared to the standard scan protocol a dose reduction of 31.1% for group 2 and 20.1% for group 3 was observed. Measurement variation of image noise was smaller for the attenuation-based dose adaptation protocols (group 2-4) (16.2-17.1%) compared to the standard scan protocol (32.3%). Regression analysis of groups 2-4 showed better correlation with improved dose usage based on BMI (all P <or= 0.001). Median image quality was "excellent" in groups 2-4 and "good" in group 1. Automated attenuation-based tube current adaptation in coronary calcium scoring is technically feasible, can decrease patient dose, and reduces variation in image noise as a sign of improved dose usage.