Prospective Coronary CT Angiography 128-MDCT Versus Retrospective 64-MDCT: Improved Image Quality and Reduced Radiation Dose

Objective New technologies for computed tomography coronary arteries imaging aim to reduce the radiation dose whilst maintaining image quality. The purpose of our study was to compare radiation dose and image quality parameters of Coronary Computed Tomography Angiography (CCTA) performed with retrospective 64-MDCT and prospective 128-MDCT. Patients and Methods A series of 77 consecutive patients were first randomised to either retrospective 64-MDCT ( n  = 37) or prospective 128-MDCT ( n  = 40) for CCTA. All patients in the retrospective 64-MDCT group were scanned with tube current modulation as strategy for reduction dose. Data regarding acquisition time and radiation dose were recorded. Two blinded radiologists independently assessed image quality of all coronary segments by using a four-point scale (1, excellent; 4, poor). Discrepancies were settled by consensus. Results No significant differences were found regarding sex, age, body weight and heart rate. CTTA effective radiation dose was 2.1 ± 0.9 vs. 8.2 ± 4 mSv in prospective and retrospective ECG-gating MDCT groups, respectively. Mean image quality score was 2.2 ± 0.9 for prospective 128-MDCT group and 1.4 ± 0.7 points for retrospective 64-MDCT representing a mean difference of 0.8 points (CI: 0.9 to 0.7). Conclusion In selected patients, CCTA using a 128-MDCT with prospective ECG-gating provides higher image quality with significant lower radiation dose when compared to 64-MDCT using retrospective ECG-gating.