应用心肌速度梯度评价胸部放疗患者左室功能的研究

Myocardial velocity gradient in assessment of left ventricular function in patients with thoracic radiotherapy

目的探讨定量组织速度成像心肌速度梯度技术在评价胸部放疗患者左室功能方面的临床价值。方法应用定量组织速度成像(QTVI)技术离线分析40例胸部肿瘤放疗患者和20例正常人(对照组)左心室各心肌节段长轴方向和短轴方向上的速度曲线,并将40例胸部肿瘤放疗患者按照放疗进程分为2组:A组治疗2.7～3.3周,照射剂量30～40 Gy;B组治疗4.1～5.5周,照射剂量50～60 Gy。测量2组收缩期峰值速度(Vs)及舒张早期峰值速度(Ve)、舒张晚期峰值速度(Va),并分别计算左心室长轴方向收缩期和舒张早期、晚期心肌速度梯度MVG1、MVG2参数及短轴方向上收缩期和舒张早期、晚期心肌速度梯度MVGs、MVGE和MVGA参数。结果 A组、B组左室二尖瓣口血流速率(E/A)比值较对照组减低(P均<0.05);B组的E/A比值较A组减低(P<0.05)。A组、B组前壁、前间隔、后壁各节段MVG1、MVG2及MVG等参数均较对照组明显减低(P均<0.05);B组前壁、前间隔、后壁各节段MVG1、MVG2及MVG等参数较A组减低(P均<0.05);A组、B组侧壁、后间隔、下壁各节段MVG1、MVG2及MVG等参数在3组之间比较均无显著性差异(P>0.05)。结论胸部放疗患者左心室长轴和短轴方向局部心肌收缩及舒张功能均存在一定程度的降低,心肌速度梯度可作为一种新方法对其评价。

Objective It is to evaluate the clinic experimental value of quantitative tissue velocity imaging （QTVI） in early assessment of thoracic radiotherapy-induced myocardial damage. Methods There were 40 patients with thoracic radiotherapy and 20 healthy controls in this study. Myocardial velocity gradient（MVG） and conventional echocardiographic parameters were performed in 60 subjects. According to the process of radiotherapy , the 40 patients were divided into two groups ： group A in which radiotherapy time was 2.7 - 3.3 weeks, radiotherapy dose was 30 - 40 Gy, group B in which radiotherapy time was 4.1 - 5.5 weeks, radiotherapy dose was 50 - 60 Gy. Off line profiles of the left ventricular regional diastolic velocity along long axis in the 40 patients and 20 healthy subjects were analyzed by QTVI. Regional diastolic velocities（ Ve ,Va） were measured at each segment of left ventricular basal, middle and apical levels. MVG were calculated respectively. Results Left ventricular inflow velocity index （E/A） of group A and group B was significantly lower than that in control group （ P 〈 0.05 ）. There was signifi- cant difference in E/A ratio between group B and group A（ P 〈 0.05 ）. MVG1 ,MVG2 and MVG of group A and group B in an- terior, anterior septal, posterior walls were significantly lower than those in control group （P 〈 0.05） ; MVG1 , MVG2 and MVG of group B in anterior, anterior septal, posterior walls were lower than those in group A （P 〈 0.05） ; MVG1 ,MVG2 and MVG of group A and group B in left lateral, posterior septal, inferior walls in all groups had no significant （ P 〉 0.05 ）. Con- clusion Regional left ventricular systolic and diastolic function were decreased in patients with thoracic radiotherapy. MVG could offer a new approach for evaluation regional left ventricular function.