无需心电门控与呼吸控制的心脏磁共振实时成像

Real-Time Cardiac Imaging Without Electrocardiogram-Gating and Respiratory Control

目的为解决传统心脏电影成像易受屏气不完全和心律不齐等影响的缺陷,并获得高时间分辨率的心脏图像,本文实现并验证一种无需心电门控与呼吸控制的实时心脏磁共振成像和重建方法。资料与方法使用低秩模型与稀疏约束实现实时成像方法。前瞻性纳入6名健康志愿者及1名心律不齐患者进行心脏磁共振扫描。通过仿真优化成像重建参数;通过健康志愿者实验比较实时方法与传统电影成像方法的一致性;进行心律不齐患者实验以验证实时方法对异常心动周期的捕捉能力。结果模型在参数为阶数L=25、约束系数λ=0.5时表现最佳;实时方法与电影方法对于射血分数、心输出量、每搏输出量指数、左心室质量的皮尔逊相关系数分别为0.9934、0.9997、0.9936、0.9916;Bland-Altman与相关系数分析结果表明,实时方法与电影方法在评估健康志愿者的左心室面积与心功能参数时高度一致,实时方法能够捕捉心律不齐患者的发病状态。结论心脏实时成像方法与传统电影方法具有高度一致性,并能够实现对心律不齐患者的异常心动周期的捕捉,具有进一步研究及临床应用价值。

Purpose To overcome the defects of being susceptible to breath-hold and arrhythmia in conventional cine CMR,and to acquire dynamic cardiac images with high temporal resolution,real-time cardiac MR imaging without ECG gating and respiratory control is achieved and validated.The consistency between the real-time and conventional cine method is compared.The feasibility for arrhythmia is evaluated.Materials and Methods Low-rank model and sparsity constraints were used.Six healthy volunteers and one arrhythmia patient were included prospectively.Simulations were used for parameter optimization.Healthy volunteer experiments were used to compare the consistency between real-time method and conventional cine method.Arrhythmia experiment was used to validate the ability of capturing irregular cardiac cycle.Results The model had better performance with rank L=25 and sparsity parameter λ=0.5.The Pearson correlation coefficient between real-time and cine methods in ejection fraction,cardiac output,stroke volume index and left ventricular mass were 0.9934,0.9997,0.9936 and 0.9916,respectively.According to the results of Bland-Altman analysis and correlation coefficient,the real-time method had great consistency with cine method in healthy volunteer experiments.Real-time method had the possibility of capturing the cardiac cycles of arrhythmia.Conclusion Real-time cardiac MRI has the great consistency with the traditional cine method,and is able to evaluate the abnormal cardiac cycles of arrhythmia patient.