Coronary computed tomography angiography during arrhythmia: Radiation dose reduction with prospectively ECG-triggered axial and retrospectively ECG-gated helical 128-slice dual-source CT
Journal of Cardiovascular Computed Tomography, 06/22/2012
Lee AM et al. – In patients with variable heart rates, prospectively electrocardiogram (ECG)–triggered axial dual–source CT (DSCT) with arrhythmia rejection algorithm is feasible and can decrease radiation exposure by –50% versus retrospectively ECG–gated helical DSCT, with preserved image quality.Methods
- This was a retrospective case–control study of 90 patients (43 PT–AAR, 47 RG–TCM) with arrhythmia (defined as heart rate variability [HRV] > 10 beats/min during data acquisition) referred for physician–supervised coronary CTA between April 2010 and September 2011.
- A subset of 22 cases matched for body mass index, HR, HRV, and other scan parameters was identified.
- Subjective image quality (4–point scale) and effective dose (dose length product method) were compared.
- PT–AAR was associated with lower effective dose than RG–TCM (4.1 vs 12.6 mSv entire cohort and 4.3 vs 9.1 mSv matched controls; both P < 0.01).
- Image quality scores were excellent in both groups (3.9 PT–AAR vs 3.6 RG–TCM) and nondiagnostic segment rates were low (0.1% vs 0.6%).
- Significantly higher image quality scores were found with PT–AAR in the entire cohort (P < 0.05), and in matched controls with high HRV > 28 beats/min (P < 0.05).