心脏磁共振四维血流成像评价肥厚型心肌病患者左心室舒张功能的可行性研究

Feasibility study of cardiac magnetic resonance four-dimensional flow imaging in evaluating left ventricular diastolic function in patients with hypertrophic cardiomyopathy

目的采用心脏磁共振四维血流(cardiac magnetic resonance four-dimensional flow,CMR 4D Flow)序列对舒张功能障碍的肥厚型心肌病(hypertrophic cardiomyopathy,HCM)患者左心室血流进行测量,探究采用左心室血流动力学特点评价舒张功能的可行性。材料与方法前瞻性纳入45例HCM患者和31例健康对照者,两组人群均进行了3.0 T磁共振稳态自由进动序列及CMR 4D Flow序列扫描。采用CVI42后处理软件测量两组人群左心室基本功能参数及左心室流入流出道层面舒张早期(左心室抽吸)及晚期(左心房主动收缩)的二尖瓣水平平均血流速度(cm/s)。采用独立样本t检验或Mann-Whitney U检验对两组受试者临床资料及影像学参数进行比较;并对舒张早期平均血流速度(E)与左心室质量(left ventricular mass,LV_(mass))、舒张期整体室壁峰值厚度(global peak wall thickness,GPWT)进行Spearman相关性分析。结果HCM组LV_(mass)及GPWT相较健康对照组明显增大[LV_(mass):(163.70±52.18)vs.(87.27±21.01),单位:g;GPWT:(19.64±3.85)vs.(9.99±2.00),单位:mm;HCM组vs.健康对照组,P<0.001];对于二尖瓣水平舒张期平均血流速度:HCM组舒张早期平均血流速度峰值(E峰)小于健康对照组[29.70(17.90)vs.50.50(16.90),单位:cm/s;HCM组vs.健康对照组,P<0.001];HCM组舒张晚期平均血流速度峰值(A峰)与健康对照组差异无统计学意义;HCM组E/A值较健康对照组明显减低[(1.26±0.70)vs.(1.80±0.85),P=0.003]。结论采用CMR 4D Flow序列能够对左心室内血流进行可视化,能够准确区分心脏在舒张早期及晚期心室内血流运动轨迹,并且二尖瓣水平舒张早期平均血流速度峰值(E峰)及E/A值降低有助于定量评价HCM患者左心室舒张功能障碍,为患者制订个体化治疗方案提供参考依据。

Objective:Cardiac magnetic resonance four-dimensional flow(CMR 4D Flow)was used to measure left ventricular blood flow in patients with hypertrophic cardiomyopathy(HCM)with impaired diastolic function relaxation and to explore the feasibility of using left ventricular hemodynamic characteristics to evaluate diastolic function.Materials and Methods:A total of 45 HCM patients and 31 healthy controls were retrospectively collected.All subjects in both groups underwent a 3.0 T magnetic resonance steady-state free entry sequence and CMR 4D Flow sequence scan.The CVI42 post-processing software was used to measure the basic functional parameters of the left ventricle and the average blood flow velocity(cm/s)at the mitral valve level in the early(left ventricular aspiration)and late(left active atrial contraction)levels of the left ventricular inflow and outflow tract in the two groups.The independent samples t-test or Mann-Whitney U test were used to compare the clinical data and imaging parameters of the two groups;and Spearman correlation analysis was performed on the average blood flow velocity in early diastole,left ventricular myocardial mass,and peak diastolic thickness of the left ventricular wall.Results:The left ventricular mass(LV_(mass))and the global peak wall thickness(GPWT)in the HCM group were significantly higher than those in the healthy control group[LV_(mass):(163.70±52.18)vs.(87.27±21.01),unit:g;GPWT:(19.64±3.85)vs.(9.99±2.00),unit:mm;HCM group vs.healthy control group,P<0.001];for the average diastolic blood flow velocity at the level of the mitral valve,the average blood flow velocity in the early diastole of the HCM group was lower than that of the healthy control group[29.70(17.90)vs.50.50(16.90),unit:cm/s;HCM group vs.healthy control group,P<0.001];the mean blood flow velocity in late diastole between HCM patients and the control group was not statistically different;the E/A value of the HCM group was significantly lower than that of the healthy control group[(1.26±0.70)vs.(1.80±0.85),HCM group vs.healthy control group,P=0.003].Conclusions:The use of CMR 4D Flow can visualize the blood flow in the left ventricle,accurately distinguish the intraventricular blood flow trajectory of the heart in the early and late diastole.In addition,the decrease of mean flow velocity in the early diastolic stage of mitral valve level(E peak)and E/A value is helpful for quantitative evaluation of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy,and provides a reference for patients to formulate individualized treatment plans.