Clinical advantages of using low tube voltage in third-generation 192-slice dual-source computed tomographic angiography before transcatheter aortic valve implantation

Low-voltage computed tomographic angiography (CTA) is a highly effective technique to reduce contrast media volume. We sought to examine the suitability of low tube voltage CTA with a reduced contrast media volume protocol using third-generation 192-slice dual-source CT in patients undergoing transcatheter aortic valve implantation (TAVI). CTA was performed to aid TAVI planning for 40 consecutive patients with severe aortic stenosis. For the first 10 patients (120/100 kV group), we used a conventional tube voltage combined CTA protocol (an ECG-gated helical scan; 120 kV, non-gated helical scan; 100 kV). For the subsequent 30 patients (70-kV group), we adopted a low tube voltage CTA protocol. We evaluated vascular attenuation, image noise, contrast-to-noise ratio (CNR), and renal function. The mean contrast media (CM) volume was 77.7 ± 17.7 mL in the 120/100-kV group and 30.9 ± 6.3 mL in the 70-kV group (P < 0.001). In the images of the aortic valve complex, the mean attenuation was not significant difference for both groups. In the images of the aorto-femoral arteries, mean attenuation was > 250 Hounsfield Units and CNR was > 10 in all vascular segments for both groups. There was no significant difference in the change of renal function in the 70-kV group, but renal function in the 120/100-kV group decreased within 1-3 months after CTA. Low tube voltage CTA using third-generation dual-source CT is suitable to assess procedural planning for TAVI. This approach maintains image quality and reduces the required CM volume.