Feasibility study of using low-kilovoltage, prospective gating, high-pitch, dual-source computed tomography prior to transcatheter aortic valve replacement: analysis of image quality and radiation dose.

Abstract

Computed tomography (CT) scans before transcatheter aortic valve replacement (TAVR) are used to evaluate the aortic valve and guide the selection of appropriate valve stents. Accurate imaging evaluation can ensure the success rate of surgery while reducing the incidence of complications. Multiple studies have adopted a protocol of coronary artery, aortic valve, and total aortic scan, with the patients receiving higher radiation doses. The aim of this study was to evaluate the image quality, radiation dose, and diagnostic performance of dual-source computed tomography (DSCT) with high-pitch spiral scanning for TAVR. A total of 240 patients being evaluated for TAVR were continuously enrolled. Based on the differences in electrocardiography (ECG) gating and tube voltage, the patients were divided into 4 groups: group A, 70-kV prospective ECG gating, high-pitch helical; group B, 70-kV retrospective ECG gating; group C, 100-kV prospective ECG gating, high-pitch helical; and group D, 120-kV prospective ECG gating, high-pitch helical. Image quality was evaluated on a 4-point scale. The image signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for objective evaluation. The radiation doses of all patients were recorded. The image quality and radiation dose of each group were compared. There were no differences in age, body mass index (BMI), subjective image quality scores, CT values between the aorta and the coronary artery, or image CNR between the 4 groups. The mean radiation doses of groups A-D were 4.13±0.69, 4.79±0.58, 12.00±1.62, and 15.01±1.90 mSv, respectively. The mean radiation dose in group A (70-kV prospective ECG gating) decreased significantly (P<0.05). Using low-kilovoltage, high-pitch DSCT can provide comparable image quality for TAVR evaluation and significantly reduce the radiation dose.