University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg, Germany.
Eur J Radiol. 2012 Nov;81(11):3568-76. doi: 10.1016/j.ejrad.2011.06.055. Epub 2011 Jul 23.
To assess the impact of body mass index (BMI)-adapted protocols and iterative reconstruction algorithms (iDose) on patient radiation exposure and image quality in patients undergoing prospective ECG-triggered 256-slice coronary computed tomography angiography (CCTA).
Image quality and radiation exposure were systematically analyzed in 100 patients. 60 Patients underwent prospective ECG-triggered CCTA using a non-tailored protocol and served as a 'control' group (Group 1: 120 kV, 200 mAs). 40 Consecutive patients with suspected coronary artery disease (CAD) underwent prospective CCTA, using BMI-adapted tube voltage and standard (Group 2: 100/120 kV, 100-200 mAs) versus reduced tube current (Group 3: 100/120 kV, 75-150 mAs). Iterative reconstructions were provided with different iDose levels and were compared to filtered back projection (FBP) reconstructions. Image quality was assessed in consensus of 2 experienced observers and using a 5-grade scale (1=best to 5=worse), and signal- and contrast-to-noise ratios (SNR and CNR) were quantified.
CCTA was performed without adverse events in all patients (n=100, heart rate of 47-87 bpm and BMI of 19-38 kg/m2). Patients examined using the non-tailored protocol in Group 1 had the highest radiation exposure (3.2±0.4 mSv), followed by Group 2 (1.7±0.7 mSv) and Group 3 (1.2±0.6 mSv) (radiation savings of 47% and 63%, respectively, p<0.001). Iterative reconstructions provided increased SNR and CNR, particularly when higher iDose level 5 was applied with Multi-Frequency reconstruction (iDose5 MFR) (14.1±4.6 versus 21.2±7.3 for SNR and 12.0±4.2 versus 18.1±6.6 for CNR, for FBP versus iDose5 MFR, respectively, p<0.001). The combination of BMI adaptation with iterative reconstruction reduced radiation exposure and simultaneously improved image quality (subjective image quality of 1.4±0.4 versus 1.9±0.5 for Group 2 reconstructed using iDose5 MFR versus Group 1 reconstructed using FBP, p<0.05).
Prospective ECG-triggered 256-slice CCTA allows for visualization of the coronary artery tree with high image quality within a wide range of heart rates and BMIs. The combination of BMI-adapted protocols with iterative reconstruction algorithms can reduce radiation exposure for the patients and simultaneously improve image quality.
评估体重指数（BMI）适应方案和迭代重建算法（iDose）对接受前瞻性心电图触发 256 层冠状动脉计算机断层血管造影（CCTA）的患者的辐射暴露和图像质量的影响。
系统分析了 100 例患者的图像质量和辐射暴露。60 例患者接受非量身定制方案的前瞻性心电图触发 CCTA，作为“对照组”（第 1 组：120kV，200mAs）。40 例连续疑似冠心病（CAD）患者接受前瞻性 CCTA，使用 BMI 适应管电压和标准（第 2 组：100/120kV，100-200mAs）与降低管电流（第 3 组：100/120kV，75-150mAs）。提供不同的 iDose 水平的迭代重建，并与滤波反投影（FBP）重建进行比较。图像质量由 2 名经验丰富的观察者进行共识评估，并使用 5 级评分（1=最佳至 5=最差）进行评估，并量化信号和对比噪声比（SNR 和 CNR）。
所有患者（n=100，心率为 47-87 次/分，BMI 为 19-38kg/m2）均成功完成 CCTA，无不良事件发生。第 1 组中使用非量身定制方案的患者辐射暴露最高（3.2±0.4mSv），其次是第 2 组（1.7±0.7mSv）和第 3 组（1.2±0.6mSv）（分别减少 47%和 63%的辐射，p<0.001）。迭代重建提供了更高的 SNR 和 CNR，尤其是当应用更高的 iDose 水平 5 与多频重建（iDose5 MFR）时（14.1±4.6 与 21.2±7.3 用于 SNR，12.0±4.2 与 18.1±6.6 用于 CNR，分别用于 FBP 与 iDose5 MFR，p<0.001）。BMI 适应与迭代重建相结合可降低辐射暴露，同时提高图像质量（第 2 组使用 iDose5 MFR 重建的主观图像质量为 1.4±0.4，第 1 组使用 FBP 重建的主观图像质量为 1.9±0.5，p<0.05）。
前瞻性心电图触发 256 层 CCTA 可在广泛的心率和 BMI 范围内实现冠状动脉树的可视化，具有较高的图像质量。BMI 适应方案与迭代重建算法的结合可降低患者的辐射暴露，同时提高图像质量。
