CT angiography for planning transcatheter aortic valve replacement using automated tube voltage selection: Image quality and radiation exposure

Abstract

Purpose: To assess image quality and accuracy of CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning performed with 3rd generation dual-source CT (DSCT).

Material and methods: We evaluated 125 patients who underwent TAVR-planning CTA on 3rd generation DSCT. A two-part protocol was performed including retrospectively ECG-gated coronary CTA (CCTA) and prospectively ECG-triggered aortoiliac CTA using 60mL of contrast medium. Automated tube voltage selection and advanced iterative reconstruction were applied. Effective dose (ED), signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Five-point scales were used for subjective image quality analysis. In patients who underwent TAVR, sizing parameters were obtained.

Results: Image quality was rated good to excellent in 97.6% of CCTA and 100% of aortoiliac CTAs. CTA studies at >100kV showed decreased objective image quality compared to 70-100kV (SNR, all p≤0.0459; CNR, all p≤0.0462). Mean ED increased continuously from 70 to >100kV (CCTA: 4.5±1.7mSv-13.6±2.9mSv, all p≤0.0233; aortoiliac CTA: 2.4±0.9mSv-6.8±2.7mSv, all p≤0.0414). In 39 patients TAVR was performed and annulus diameter was within the recommended range in all patients. No severe cardiac or vascular complications were noted.

Conclusion: 3rd generation DSCT provides diagnostic image quality in TAVR-planning CTA and facilitates reliable assessment of TAVR device and delivery option while reducing radiation dose.

Keywords: Automated tube voltage selection; Dual-source CT; Pre-procedural CT angiography; Radiation dose reduction; Transcatheter aortic valve replacement.