Yang Ching-Ching, Law Wei-Yip, Lu Kun-Mu, Wu Tung-Hsin
1Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan.
2Department of Radiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
Br J Radiol. 2019 Sep;92(1101):20180945. doi: 10.1259/bjr.20180945. Epub 2019 Jul 29.
This study aimed to evaluate the relationship between heart rate (HR) and optimal reconstruction phase in prospectively electrocardiogram (ECG)-triggered coronary CT angiography (CCTA) performed on a newly introduced 256-slice multidetector CT (MDCT).
All the cases were selected retrospectively from the patients scheduled for CCTA in our department between January and April 2017. The scanner selected the optimal exposure phase based on 10 s ECG recordings. To ensure the success of CCTA, the operator also checked patient's age, breathing control, emotional status and past medical history to decide whether the automatically selected scan phase needs manual adjustment or not. Images were reconstructed in 1% steps of the RR interval to determine the cardiac phase with least coronary motion. If CCTA images showed moderate motion blurring or discontinuity in the course of coronary segments, a cardiac motion correction algorithm was applied to the reconstructed images. Subjective diagnostic image quality was evaluated with 4-point grading scale.
A total of 87 consecutive CCTA examinations were investigated in this study. Diastolic reconstruction was applied to all vessel segments in patients with HR <63 bpm, where 36.5 and 77.8% of vessel segments were reconstructed with the use of motion correction in HR ≤57 and 58-62 bpm, respectively. As for patients with HR ≥63 bpm, 89.3 and 71.7% of vessel segments were reconstructed in diastole in HR 63-67 and ≥68 bpm, respectively, while 81 and 100% of vessel segments were reconstructed with the use of motion correction in the same HR groups.
Based on our results, a HR less than 67 bpm can be used to identify appropriate patients for diastolic reconstruction. Although the motion correction algorithm is an effective approach to reduce the impact of cardiac motion in CCTA, HR control is still important to optimize the image quality of CCTA. The relationship between HR and optimal reconstruction phase established in this study could be further used to tailor the ECG pulsing window for dose reduction in patients undergoing CCTA performed on the 256-slice MDCT.
The HR thresholds to identify patients who are the best suitable candidates for diastolic or systolic reconstruction are scanner specific. This study investigated the relationship between HR and optimal reconstruction phase in prospectively ECG-triggered CCTA for a newly introduced 256-slice MDCT. Once the relationship is established, it could be used to tailor the ECG pulsing window for radiation dose reduction.
本研究旨在评估在新引进的256层多排螺旋CT（MDCT）上进行的前瞻性心电图（ECG）触发冠状动脉CT血管造影（CCTA）中，心率（HR）与最佳重建期之间的关系。
所有病例均回顾性选取自2017年1月至4月在我科计划行CCTA的患者。扫描仪根据10秒的ECG记录选择最佳曝光期。为确保CCTA成功，操作人员还检查患者的年龄、呼吸控制、情绪状态和既往病史，以决定自动选择的扫描期是否需要手动调整。图像以RR间期的1%步长重建，以确定冠状动脉运动最小的心动周期。如果CCTA图像在冠状动脉节段过程中显示中度运动模糊或不连续，则对重建图像应用心脏运动校正算法。主观诊断图像质量采用4分制评分。
本研究共调查了87例连续的CCTA检查。HR<63次/分的患者，所有血管节段均采用舒张期重建，其中HR≤57次/分和58 - 62次/分的患者分别有36.5%和77.8%的血管节段采用运动校正重建。HR≥63次/分的患者，HR 63 - 67次/分和≥68次/分的患者分别有89.3%和71.7%的血管节段在舒张期重建，而在相同HR组中分别有81%和100%的血管节段采用运动校正重建。
根据我们的结果，HR小于67次/分可用于识别适合舒张期重建的患者。虽然运动校正算法是减少CCTA中心脏运动影响的有效方法，但HR控制对于优化CCTA图像质量仍然很重要。本研究中建立的HR与最佳重建期之间的关系可进一步用于为在256层MDCT上进行CCTA的患者调整ECG脉冲窗口以降低辐射剂量。
识别最适合舒张期或收缩期重建患者的HR阈值因扫描仪而异。本研究调查了新引进的256层MDCT前瞻性ECG触发CCTA中HR与最佳重建期之间的关系。一旦建立这种关系，就可用于调整ECG脉冲窗口以降低辐射剂量。
