Prospective ECG-gated coronary 320-MDCT angiography with absolute acquisition delay strategy for patients with...

The purpose of this study was to evaluate image quality and radiation dose when patients with atrial fibrillation undergo coronary CT angiography (CTA) using prospectively ECG-gated 320-MDCT technology with an absolute-delay strategy.

A cohort of 75 consecutive patients (60 men and 15 women; age (± SD), 71 ± 10 years) who underwent prospectively ECG-gated coronary CTA using a 320-MDCT scanner during atrial fibrillation was matched with 75 control patients imaged in sinus rhythm. All coronary CTA for the atrial fibrillation cohort used absolute-delay strategy. Subjective image quality score and the dose-length product (DLP) were compared between the two cohorts and, for the atrial fibrillation cohort, among those patients imaged over a different number of heartbeats. The accuracy of stenosis detection was evaluated in 17 studies of the atrial fibrillation cohort using catheter angiography as a reference standard.

For those patients imaged in atrial fibrillation, one- and two-beat acquisitions were performed in 26.7% (n = 20) and 40% (n = 30) of patients, respectively. There was no significant difference in image quality between the atrial fibrillation (2.9 ± 0.4) and sinus rhythm (2.9 ± 0.3) cohorts, nor was there a difference in image quality with respect to the number of heartbeats used in the acquisition. The atrial fibrillation cohort had an 80% higher DLP (680 ± 470 vs 372 ± 236 mGy × cm, p < 0.0001). The patient-based sensitivity and negative predictive value for stenosis detection were both 100%.

Using an absolute-delay strategy, two thirds of patients who underwent prospectively ECG-gated coronary CTA using a 320-MDCT scanner were imaged within two heartbeats or fewer. Compared with patients imaged in sinus rhythm, the image quality was comparative and the radiation dose was 1.8-fold higher.