低管电压在 CCTA 中的应用：来自 PROTECTION VI 研究的结果。
Application of Low Tube Potentials in CCTA: Results From the PROTECTION VI Study.
机构信息
Medizinische Klinik und Poliklinik I, Ludwig Maximilians-Universität, Munich, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany.
University of British Columbia, Vancouver, Canada.
出版信息
JACC Cardiovasc Imaging. 2020 Feb;13(2 Pt 1):425-434. doi: 10.1016/j.jcmg.2019.03.030. Epub 2019 Jun 12.
OBJECTIVES
The aim of this study was to assess the use of low tube potentials for coronary computed tomography angiography (CCTA) in worldwide clinical practice and its influence on radiation exposure, contrast agent volume, and image quality.
BACKGROUND
CCTA is frequently used in clinical practice. Lowering of tube potential is a potent method to reduce radiation exposure and to economize contrast agent volume.
METHODS
CCTAs of 4,006 patients from 61 international study sites were analyzed regarding very-low (≤80 kVp), low (90 to 100 kVp), conventional (110 to 120 kVp), and high (≥130 kVp) tube potentials. The impact on dose-length product (DLP) and contrast agent volume was analyzed. Image quality was determined by evaluation of the diagnostic applicability and assessment of the objective image parameters signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR).
RESULTS
When compared with conventional tube potentials, low tube potentials were used in 56% of CCTAs (≤80 kVp: 9%; 90 to 100 kVp: 47%), which varied among sites from 0% to 100%. Tube potential reduction was associated with low-cardiovascular risk profile, low body mass index (BMI), and new-generation scanners. Median radiation exposure was lowered by 68% or 50% and median contrast agent volume by 25% or 13% for tube potential protocols of ≤80 kVp or 90 to 100 kVp when compared with conventional tube potentials, respectively (all p < 0.001). With the use of lower tube potentials, the frequency of diagnostic scans was maintained (p = 0.41), whereas SNR and CNR significantly improved (both p < 0.001). Considering BMI eligibility criteria, 58% (n = 946) of conventionally scanned patients would have been suitable for low tube potential protocols, and 44% (n = 831) of patients scanned with 90 to 100 kVp would have been eligible for very-low tube potential CCTA imaging of ≤80 kVp.
CONCLUSIONS
This large international registry confirms the feasibility of tube potential reduction in clinical practice leading to lower radiation exposure and lower contrast volumes. The current registry also demonstrates that this strategy is still underused in daily practice. (PROspective multicenter registry on radiaTion dose Estimates of cardiac CT angIOgraphy iN daily practice in 2017 [PROTECTION-VI]; NCT02996903).
目的
本研究旨在评估在全球临床实践中使用低管电压进行冠状动脉 CT 血管造影（CCTA）的情况，及其对辐射暴露、对比剂用量和图像质量的影响。
背景
CCTA 在临床实践中经常使用。降低管电压是降低辐射暴露和节约对比剂用量的有效方法。
方法
对来自 61 个国际研究地点的 4006 例患者的 CCTA 进行分析，分为极低（≤80 kVp）、低（90 至 100 kVp）、常规（110 至 120 kVp）和高（≥130 kVp）管电压组。分析剂量长度乘积（DLP）和对比剂用量的影响。通过评估诊断适用性和测量客观图像参数信噪比（SNR）和对比噪声比（CNR）来确定图像质量。
结果
与常规管电压相比，低管电压在 56%的 CCTA 中（≤80 kVp：9%；90 至 100 kVp：47%）得到应用，不同研究点的使用率为 0%至 100%。管电压降低与心血管风险低、低体重指数（BMI）和新一代扫描仪有关。与常规管电压相比，≤80 kVp 或 90 至 100 kVp 管电压方案可使辐射暴露中位数降低 68%或 50%，对比剂用量中位数降低 25%或 13%（均 p<0.001）。使用较低的管电压时，诊断扫描的频率保持不变（p=0.41），而 SNR 和 CNR 则显著提高（均 p<0.001）。根据 BMI 合格标准，58%（n=946）的常规扫描患者适合低管电压方案，44%（n=831）的 90 至 100 kVp 扫描患者适合≤80 kVp 的超低管电压 CCTA 成像。
结论
本大规模国际注册研究证实了在临床实践中降低管电压的可行性，可降低辐射暴露和对比剂用量。目前的注册研究还表明，该策略在日常实践中仍未得到充分应用。（前瞻性多中心注册研究 2017 年心脏 CT 血管造影的辐射剂量估计在日常实践中[PROTECTION-VI]；NCT02996903）。
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