Gender influence on dose saving allowed by prospective-triggered 64-slice multidetector computed tomography coronary angiography as compared with retrospective-gated mode

BACKGROUND/OBJECTIVES:
To assess the gender influence on radiation dose saving allowed by prospective ECG-triggered MDCT coronary angiography (P-MDCT-CA) in comparison with retrospective ECG-gated MDCT-CA (R-MDCT-CA). The influence of kilovoltage and body mass index on radiation dose and the impact of different parameters on image quality (IQ) and diagnostic confidence (DC), were also determined.
METHODS:
64-slice MDCT-CA was performed in 176 patients: 66 R-MDCT-CA and 110 P-MDCT-CA. Effective dose was determined using ImpactDose software based on Monte Carlo method. Three point scales were used to assess IQ and DC on a segmental basis.
RESULTS:
Patients were divided into 4 groups according with the examination performed: group A (90 pts, coronary tree assessment with P-MDCT-CA); group B (55 pts, coronary tree assessment with R-MDCT-CA); group C (20 pts, bypass grafts assessment with P-MDCT-CA); and group D (11 pts, bypass grafts assessment with R-MDCT-CA). Effective dose was 68% lower for P-MDCT-CA than R-MDCT-CA for coronary artery studies (Gr. A=4.7 ± 1.69 mSv and Gr. B=14.9 ± 4.4 mSv; p<0.05) and 63% lower for by-pass studies. Effective dose resulted significantly higher in women than in men who underwent R-MDCT-CA; conversely, no gender impact was observed on effective dose of P-MDCT-CA. As a result, dose saving with prospective gating was more pronounced in women (73%; R-MDCT-CA:16.3 mSv, P-MDCT-CA:4.5 mSv,) than in men (60%; R-MDCT-CA:12.8 mSv, P-MDCT-CA:4.8 mSv). IQ and DC of P-MDCT-CA were better or comparable than R-MDCT-CA
CONCLUSIONS: P-MDCT-CA provides at least comparable IQ and DC than R-MDCT-CA with significant dose saving. This study highlights the important advantage offered by using P-MDCT-CA in female patients.