Wang Yiming, Wang Geliang, Huang Xin, Zhao Wenzhe, Zeng Qiang, Li Yanshou, Guo Jianxin
Department of Radiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Quant Imaging Med Surg. 2023 May 1;13(5):2933-2940. doi: 10.21037/qims-22-186. Epub 2023 Mar 9.
Coronary computed tomography angiography (CTA) has been increasingly used to identify the degree of coronary artery stenosis and plaque lesions in vessels. This study evaluated the feasibility of using high-definition (HD) scanning with high-level deep learning image reconstruction (DLIR-H) to improve the image quality and spatial resolution when imaging calcified plaques and stents in coronary CTA as compared to the standard definition (SD) reconstruction mode with adaptive statistical iterative reconstruction-V (ASIR-V).
A total of 34 patients (age 63.3±10.9 years; 55.88% female) with calcified plaques and/or stents who underwent coronary CTA in HD-mode were included in this study. Images were reconstructed with SD-ASIR-V, HD-ASIR-V, and HD-DLIR-H. Subjective image quality with image noise and clarity of vessels, calcifications, and stented lumens was evaluated by 2 radiologists using a 5-point scale. The kappa (κ) test was used to analyze the interobserver agreement. Objective image quality with image noise, signal-to-noise-ratio (SNR), and contrast-to-noise-ratio (CNR) was measured and compared. Image spatial resolution and beam-hardening artifacts (BHAs) were also evaluated using the calcification diameter and CT numbers in 3 points along the stented lumen (inside, at the proximal and distal ends just outside stent).
There were 45 calcified plaques and 4 coronary stents. HD-DLIR-H images had the highest overall image quality score (4.50±0.63) with the lowest image noise (22.59±3.59 HU) and the highest SNR (18.30±4.88) and CNR (26.56±6.33), followed by SD-ASIR-V50% image quality score (4.06±2.49), image noise (35.02±8.09 HU), SNR (12.77±1.59), CNR(15.67±1.92) and HD-ASIR-V50% image quality score (3.90±0.64), image noise (57.7±12.03 HU), SNR (8.16±1.86), CNR (10.01±2.39). HD-DLIR-H images also had the smallest calcification diameter measurement (2.36±1.58 mm), followed by HD-ASIR-V50% (3.46±2.07 mm) and SD-ASIR-V50% (4.06±2.49 mm). HD-DLIR-H images had the closest CT value measurements for the 3 points along the stented lumen, indicating much less BHA. Interobserver agreement on the image quality assessment was good to excellent (HD-DLIR-H: κ value =0.783; HD-ASIR-V50%: κ value =0.789; SD-ASIR-V50%: κ value =0.671).
Coronary CTA with HD scan mode and DLIR-H significantly improves the spatial resolution for displaying calcifications and in-stent lumens while simultaneously reducing image noise.
冠状动脉计算机断层扫描血管造影（CTA）已越来越多地用于识别血管中冠状动脉狭窄程度和斑块病变。本研究评估了与采用自适应统计迭代重建-V（ASIR-V）的标准定义（SD）重建模式相比，使用高清（HD）扫描和高级深度学习图像重建（DLIR-H）来提高冠状动脉CTA中钙化斑块和支架成像时的图像质量和空间分辨率的可行性。
本研究纳入了34例（年龄63.3±10.9岁；55.88%为女性）在HD模式下接受冠状动脉CTA检查且有钙化斑块和/或支架的患者。图像采用SD–ASIR-V、HD–ASIR-V和HD–DLIR-H进行重建。2名放射科医生使用5分制对图像噪声以及血管、钙化和支架内腔清晰度的主观图像质量进行评估。采用kappa（κ）检验分析观察者间的一致性。测量并比较具有图像噪声、信噪比（SNR）和对比噪声比（CNR）的客观图像质量。还使用沿支架内腔3个点（内部、支架近端和远端外侧）的钙化直径和CT值评估图像空间分辨率和束硬化伪影（BHA）。
共有45个钙化斑块和4个冠状动脉支架。HD–DLIR-H图像的总体图像质量评分最高（4.50±0.63），图像噪声最低（22.59±3.59 HU），SNR最高（18.30±4.88）和CNR最高（26.56±6.33），其次是SD–ASIR-V50%图像质量评分（4.06±2.49）、图像噪声（35.02±8.09 HU）、SNR（12.77±1.59）、CNR（15.67±1.92）以及HD–ASIR-V50%图像质量评分（3.90±0.64）、图像噪声（57.7±12.03 HU）、SNR（8.16±1.86）、CNR（10.01±2.39）。HD–DLIR-H图像的钙化直径测量值也最小（2.36±1.58 mm），其次是HD–ASIR-V50%（3.46±2.07 mm）和SD–ASIR-V50%（4.06±2.49 mm）。HD–DLIR-H图像沿支架内腔3个点的CT值测量最接近，表明BHA少得多。观察者间对图像质量评估的一致性良好至优秀（HD–DLIR-H：κ值 =0.783；HD–ASIR-V50%：κ值 =0.789；SD–ASIR-V50%：κ值 =0.671）。
采用HD扫描模式和DLIR-H的冠状动脉CTA显著提高了显示钙化和支架内腔的空间分辨率，同时降低了图像噪声。
