The Impact of Different Levels of Adaptive Iterative Dose Reduction 3D on Image Quality of 320-Row Coronary CT Angiography: A Clinical Trial

PurposeThe aim of this study was the systematic image quality evaluation of coronary CT angiography (CTA), reconstructed with the 3 different levels of adaptive iterative dose reduction (AIDR 3D) and compared to filtered back projection (FBP) with quantum denoising software (QDS).MethodsStandard-dose CTA raw data of 30 patients with mean radiation dose of 3.2 ± 2.6 mSv were reconstructed using AIDR 3D mild, standard, strong and compared to FBP/QDS. Objective image quality comparison (signal, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), contour sharpness) was performed using 21 measurement points per patient, including measurements in each coronary artery from proximal to distal.ResultsObjective image quality parameters improved with increasing levels of AIDR 3D. Noise was lowest in AIDR 3D strong (p≤0.001 at 20/21 measurement points; compared with FBP/QDS). Signal and contour sharpness analysis showed no significant difference between the reconstruction algorithms for most measurement points. Best coronary SNR and CNR were achieved with AIDR 3D strong. No loss of SNR or CNR in distal segments was seen with AIDR 3D as compared to FBP.ConclusionsOn standard-dose coronary CTA images, AIDR 3D strong showed higher objective image quality than FBP/QDS without reducing contour sharpness.Trial RegistrationClinicaltrials.gov NCT00967876

研究目的：本研究旨在对采用3种不同等级自适应迭代剂量重建（Adaptive Iterative Dose Reduction, AIDR 3D）算法重建的冠状动脉计算机断层血管造影（Coronary CT Angiography, CTA）图像进行系统性质量评价，并与搭载量子降噪软件（Quantum Denoising Software, QDS）的滤波反投影（Filtered Back Projection, FBP）算法进行对比。
研究方法：本研究纳入30例患者的标准剂量冠状动脉CTA原始数据，其平均辐射剂量为3.2±2.6 mSv。采用轻度、标准、高强度3种等级的AIDR 3D算法进行图像重建，并与FBP/QDS算法的重建结果进行对比。基于每位患者21个测量点位（涵盖各冠状动脉近段至远段的测量点），开展客观图像质量对比分析，包括信号强度、噪声水平、信噪比（Signal-to-Noise Ratio, SNR）、对比信噪比（Contrast-to-Noise Ratio, CNR）及轮廓清晰度等指标。
研究结果：客观图像质量参数随AIDR 3D算法强度提升而改善。在高强度AIDR 3D重建图像中，噪声水平最低（与FBP/QDS相比，21个测量点位中有20个点位的p值≤0.001）。信号强度与轮廓清晰度分析显示，多数测量点位下不同重建算法间无显著差异。高强度AIDR 3D可获得最优的冠状动脉SNR与CNR。与FBP算法相比，采用AIDR 3D算法重建的图像在远端血管节段未出现SNR与CNR下降的情况。
研究结论：在标准剂量冠状动脉CTA图像中，高强度AIDR 3D算法相较于FBP/QDS算法可获得更高的客观图像质量，且未降低图像轮廓清晰度。
试验注册：Clinicaltrials.gov NCT00967876