Departments of Medicine and Radiology, University of Chicago Medical Center, Chicago, IL, United States.
Department of CT Clinical Science, Philips Healthcare, Cleveland, OH, United States.
Eur J Radiol. 2019 May;114:1-5. doi: 10.1016/j.ejrad.2019.02.010. Epub 2019 Mar 2.
Vasodilator stress computed tomography perfusion (sCTP) imaging is complementary to coronary CT angiography (CCTA), used to determine the hemodynamic significance of coronary artery disease. However, it requires a separate image acquisition due to motion artifacts caused by higher heart rates during stress, resulting in increased iodine contrast dose and radiation. We sought to determine whether a novel motion correction algorithm applied to stress images would improve the visualization of the coronary arteries to potentially allow CCTA + sCTP evaluation in a single scan.
28 patients referred for clinically indicated CCTA (iCT, Philips) underwent sCTP imaging (retrospective-gating with dose modulation; 100 kVp and 250 mA; 5.2 ± 4.3 mSv) after regadenoson (0.4 mg, Astellas). Stress images were reconstructed using standard filtered back-projection (FBP) and also processed to generate interaction-free coronary motion-compensated back-projection reconstructions (MCR). Each coronary artery from standard FBP and MCR images was viewed side-by-side by a reader blinded to the reconstruction technique, who graded severity of motion artifact by segment (scale 0-5, with 3 as the threshold for diagnostic quality) and to measure signal-to-noise and contrast-to-noise ratios (SNR, CNR).
Visualization scores were higher with MCR for all coronary segments, including 14/86 (16%) segments deemed as non-diagnostic on FBP images. SNR (7 ± 2) and CNR (15 ± 8) were unchanged by motion-correction (7 ± 3, p = 0.88 and 15 ± 5, p = 0.94, respectively).
MCR improves the visualization of coronary anatomy on sCTP images without degrading image characteristics. This algorithm is an important step towards the combined assessment of coronary anatomy and myocardial perfusion in a single scan, which will reduce study time, radiation exposure and contrast dose.
血管扩张剂应激计算机断层灌注（sCTP）成像与冠状动脉 CT 血管造影（CCTA）互补，用于确定冠状动脉疾病的血流动力学意义。然而，由于应激时心率较高导致运动伪影，需要单独进行图像采集，从而导致碘造影剂剂量和辐射增加。我们旨在确定应用于应激图像的新型运动校正算法是否会改善冠状动脉的可视化效果，从而有可能在单次扫描中同时评估 CCTA+sCTP。
28 例因临床需要而行 CCTA（飞利浦 iCT）检查的患者，在瑞加德松（Astellas，0.4mg）给药后行 sCTP 成像（回顾性门控，剂量调制；100kVp 和 250mA；5.2±4.3mSv）。应激图像采用标准滤波反投影（FBP）重建，也采用生成无相互作用的冠状动脉运动补偿反投影重建（MCR）进行处理。由一位对重建技术不知情的读者对标准 FBP 和 MCR 图像的每根冠状动脉进行并排观察，根据节段对运动伪影的严重程度进行评分（0-5 分，3 分为诊断质量阈值），并测量信号噪声比（SNR）和对比噪声比（CNR）。
对于所有冠状动脉节段，MCR 的可视化评分均高于 FBP，包括 14/86（16%）的节段在 FBP 图像上被认为是不可诊断的。运动校正后 SNR（7±2）和 CNR（15±8）无变化（分别为 7±3，p=0.88 和 15±5，p=0.94）。
MCR 可改善 sCTP 图像上的冠状动脉解剖结构可视化效果，而不会降低图像特征。该算法是在单次扫描中联合评估冠状动脉解剖结构和心肌灌注的重要步骤，这将减少检查时间、辐射暴露和造影剂剂量。
