血流向量成像技术在判断冠状动脉狭窄程度中的应用价值

Application value of vector flow mapping in assessing the degrees of coronary artery stenosis

目的应用血流向量成像（VFM）技术定量评价冠状动脉不同狭窄程度患者在心动周期不同时相左室腔内血流流场状态，探讨VFM定量参数在判断冠状动脉狭窄程度中的应用价值。方法选取84例经冠脉造影证实的冠状动脉狭窄患者为病例组，并依据造影结果将其分为轻度狭窄组（Ⅰ组）、中度狭窄组（Ⅱ组）、重度狭窄组（Ⅲ组），另选45例健康志愿者作为对照组。比较病例组与对照组间左室循环参数（循环强度、涡旋面积）、总体及各节段的平均能量损耗（aEL）在整个心动周期不同时相的变化。将aEL、循环强度、涡旋面积与侧壁E／e’（L）、间隔E／e’（S）进行相关性分析。结果①与对照组相比，Ⅲ组在等容舒张期、缓慢充盈期、心房收缩期及等容收缩期，Ⅱ组在缓慢充盈期、心房收缩期及等容收缩期左心室总体及部分节段aEL均增高（P〈0．05）；Ⅰ组左心室在缓慢充盈期中间段aEL增高（P〈0．05）；②与对照组相比，Ⅲ组在等容舒张期、缓慢充盈期、心房收缩期及等容收缩期左心室涡旋面积及循环强度均增高（P〈0．05）；③病例组在快速充盈期总体、基底段、中间段及房缩期总体、基底段aEL与E／e’（L）及E／e’（S）均呈正相关。缓慢充盈期及心房收缩期涡旋面积及循环强度与E／e’（L）及E／e’（S）呈正相关。结论VFM技术可直观地反映左室血流流场情况，在一定程度上反映冠状动脉狭窄程度。

Objective To quantify the left ventricular flow field characteristics of different phases of cardiac cycle in patients with different degrees of coronary artery stenosis by using vector flow mapping （VFM）, and explore the value of quantitative parameters of VFM in diagnosis of degrees of coronary artery stenosis in patients with coronary heart disease. Methods Eighty-four patients with coronary artery stenosis showed by coronary angiography served as case group. According to the results of coronary angiography, all the patients of case group were divided into 3 groups：mild stenosis group, moderate stenosis group and severe stenosis group. Forty-five healthy adult volunteers were selected as control group. The quantitative parameters, including average energy loss （EL-base, EL-mid, EL-apex） and circulation （vortex area, circulation）, were measured in the different periods of VFM mode. The difference of parameters were evaluated between case group and control group during different periods. E/e＇ was derived via dual-Doppler imaging technology and correlation was analyzed between aEL, circulation, E/e＇ （L） and E/e＇ （S）, separately. ROC curve was used to analyze aEL in severe stenosis group, and to evaluate the diagnostic efficacy of aEL in different cardiac cycles. Results ①Compared with the control group, aEL in global and regional segment of left ventricle in the severe stenosis group were significantly increased during isovolumetric relaxation period, reduced filling period, atrial systolic phase and isovolumic contraction period （all P 〈0.05）. And the aEL in global and regional segment of left ventricular in the moderate stenosis group were significantly increased during reduced filling period, atrial systolic phase and isovolumic contraction period （all P 〈0.05）. And the aEL in middle segment of left ventricular in the mild stenosis group was significantly increased during reduced filling period （ P 〈0.05）. ②Compared with the control group, the vortex area and circulation intensity in left ventricular of the severe stenosis group were significantly increased during isovolumetric relaxation period, reduced filling period, atrial systolic phase and isovolumic contraction period（ P 〈0.05）. ③In case group, there were positive correlations between aEL with E/e＇ （L） or E/e＇（S） at global and regional segment of rapid filling phase and atrial systolic phase. And there were positive correlations between the vortex area or circulation intensity and E/e＇ （L） or E/e＇ （S） during reduced filling period and atrial systolic phase. Conclusions VFM can effectively evaluate the flow field characteristics of left ventricle in patients with coronary heart disease. The quantitative parameters of VFM can reflect the extent of coronary artery stenosis in some extent.