Application of low tube voltage combined with low iodine load iso-osmolar contrast in CT angiography for thanscatheter aortic valve replacement planning

Abstract

Objective To investigate the feasibility, image quality, and safety of low-tube-voltage, low iodine load iso-osmolar contrast comprehensive cardiac and aortoiliac CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning. Methods Ninety-eight consecutive TAVR candidates prospectively underwent combined contrast-enhanced CTA of the aortic root complex and vascular access route. Patients were assigned to group A (2nd generation dual-source CT, 100 kV, contrast 270 mgI/ml iodixanol) or group B (2nd generation dual-source CT, 120 kV, contrast 370 mgI/ml). Mean vascular attenuation, noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of aorta including aortic root, aortic arch, descending aorta at level of diaphragm, abdominal aorta at level of renal artery and femoral artery were compared. Patient creatinine levels before the examination of CTA and during follow-up (24—48 h) were measured. Results The image quality score of aortic root and whole aorta was (4.2±0.7) and (4.3±0.4) respectively in experimental group, (4.3±0.6) and (4.3±0.3) in control group. No significant difference in subjective image quality score between two groups including aortic root image and whole aorta image (t=-0.130,-0.155,P=0.694, 0.822). The image noise of aortic root and femoral artery were higher in experimental group than that in control group (P<0.05). Radiation dose in experimental group was higher than that in control group [(6.1±0.4) vs. (8.0±0.4) mSv, t=-9.253, P=0.001]. There were no significant changes in creatinine levels among groups during the follow-up. Conclusion TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low iodine load iso-osmolar contrast using low-tube-voltage acquisition. Key words: Thanscatheter aortic valve replacement; Tomography, X-ray computed; Iso-osomolar contrast; Low tube voltage