Abstract 2753: Predicting Success of Prospective Gating in Dual Source Coronary CTA: Development of a Model and Initial Experience
Background: Prospectively gated (PG) coronary CTA (PG-CCTA) with dual source CT (DSCT) allows dramatic reduction of radiation burden, but requires prospective phase selection and assessment of likelihood of adequate image quality. We developed and tested the model for predicting success of PG-CCTA
Methods: Retrospectively gated (RG) CCTA was acquired with DSCT in 103 consecutive pts. Two experienced assessed by consensus whether diagnostic quality images could have been obtained in a single predefined phase (70% of RR interval), thereby identifying pts in whom PG scan would be successful. Potential predictors of success entered in a model included age, BMI, coronary calcium score (CCS), beta-blocker use, average HR (HR), and HR variation during CCS acquisition before CCTA. The model was subsequently applied in 9 consecutive pts
Results: Of 1633 coronary segments (segs) assessed in 103 pts with RG-CCTA, 28 (0.2%) in 12 pts were unevaluable, and 63 segs (0.4%) in 16 pts required phase change. HR was ≤ 70 BPM during CCS acquisition in 83 pts (80.6%), of whom 59 (71%) could be analyzed with a single 70% RR phase compared to only 10% of pts with HR>70. By logistic regression HR ≤ 70 ( OR= 0.024, p<0.0001), HR variation / 5 BPM ( OR = 0.88, p=0.04), CCS / 100 ( OR=0.84, p=0.01) and BMI (OR 0.9, p=0.04) were independent predictors of a successful single phase CCTA. Over 90% of pts with HR<70 and CCS<100 could be analyzed with 70% RR phase (Figure⇓). Applying this model, 9 consecutive pts had excellent PG CCTA with low radiation dose (3.1±0.4 mSv) vs 15.9±5.2mSv for RG-CCTA (p<.0001).
Conclusion: PG-CCTA drastically reduces radiation dose and is feasible with HR 3 70, low pre-scan HR variation and low CCS.