斑点追踪技术对中晚孕期胎儿二尖瓣环位移特征的研究

Study on the characteristics of mitral annular displacement in middle and late pregnancy fetuses based on speckle tracking imaging

目的应用二维超声斑点追踪(speckle tracking imaging , ST I)技术评价中晚孕期正常胎儿纵向不同方向二尖瓣环位移(mitral annular plane systolic excursion , M APSE)的特征.方法选取76例孕26~32周正常中晚孕胎儿,应用STI技术记录室间隔侧二尖瓣环与心尖横向水平三个不同方向A 、 B 、 C点的时间-位移曲线,并分别记录三点的达峰位移(SEPT‐M APSE‐A 、 SEPT‐M APSE‐B 、SEPT‐M APSE‐C)及达峰时间(the time to peak , T T P : SEPT‐T T P‐A 、 SEPT‐T T P‐B 、 SEPT‐T T P‐C);再记录侧壁侧二尖瓣环与心尖横向水平三个不同方向 A、B、C点的时间位移曲线,分别记录三点的达峰位移(LA T‐M APSE‐A 、 LA T‐M APSE‐B 、 LA T‐M APSE‐C )及达峰时间(LAT‐T T P‐A 、 LA T‐T T P‐B 、 LA T‐T T P‐C);应用解剖M型超声心动图(free angle M‐mode echocardiography , FAM )测量胎儿侧壁侧二尖瓣环位移(FAM‐MAPSE).对所得数据进行统计学分析.结果侧壁侧二尖瓣环A 、 B 、 C点达峰位移[LAT‐MAPSE‐A (3 .62 ± 1 .01) mm , LAT‐MAPSE‐B (3 .95 ± 1 .04) mm , LAT‐MAPSE‐C (4 .45 ± 1 .05) mm]均大于室间隔侧二尖瓣环对应三点的位移[SEPT‐M APSE‐A (3 .41 ± 0 .63 ) mm , SEPT‐M APSE‐B (3 .07 ± 0 .50) mm , SEPT‐M APSE‐C (2 .82 ± 0 .51) mm],二尖瓣环纵向各方向位移以LAT‐MAPSE‐C及SEPT‐M APSE‐A最大, B 、 C点差异具有统计学意义( P <0 .05),A点差异无统计学意义( P >0 .05);LAT‐M APSE‐C小于FAM‐M APSE [(6 .06 ± 1 .35) mm ],差异具有统计学意义(P <0 .05),并具有较好的相关性(r =0.896 ,P <0 .05);室间隔侧二尖瓣环A、B、C点达峰时间[SEPT‐T T P‐A (0 .210 ± 0 .008 ) s , SEPT‐T T P‐B (0 .213 ± 0 .008 ) s , SEPT‐T TP‐C (0 .210 ± 0 .005) s]之间差异无统计学意义( P >0 .05);侧壁侧二尖瓣环A 、 B 、 C点达峰时间[LAT‐TTP‐A (0 .210 ± 0 .008) s 、 LA T‐T T P‐B (0 .213 ± 0 .006) s 、 LA T‐T T P‐C (0 .210 ± 0 .007) s]之间差异无统计学意义(均 P >0 .05).结论中晚孕期胎儿左室壁纵向收缩运动具有较好的同步性,胎儿二尖瓣环纵向运动是多方向不同程度位移的综合运动,以垂直于瓣环方向的运动为最大位移方向;STI技术测定的二尖瓣环位移参数能反映左室纵向收缩功能,对评价胎儿左心室纵向收缩功能具有临床应用价值.

Objective To assess the longitudinal mitral annular plane systolic excursion (MAPSE) of different directions in normal fetuses during mid-late pregnancy based on two-dimensional speckle tracking imaging (STI). Methods Seventy-six normal fetuses during middle and late pregnancy were selected at 26-32 weeks of gestation. The peak MAPSE was measured by free angle M-mode echocardiography (FAM) perpendicular to the lateral annulus in the mitral annular plane. The time-displacement curves of interventricular septal mitral annulus in three different directions including points A, B and C through transverse level of apex were recorded by STI. The peak MAPSE of interventricular septal mitral annulus (SEPT-MAPSE-A, SEPT-MAPSE-B, SEPT-MAPSE-C) in three different directions including points A, B and C and the time to peak (TTP: SEPT-TTP-A, SEPT-TTP-B, SEPT-TTP-C) were recorded respectively. The time-displacement curves of lateral mitral annulus in three different directions including points A, B and C through transverse level of apex were recorded by STI. The peak MAPSE of lateral mitral annulus (LAT-MAPSE-A, LAT-MAPSE-B, LAT-MAPSE-C) in three different directions including points A, B and C, the time to peak(LAT-TTP-A, LAT-TTP-B, LAT-TTP-C) were recorded respectively. Finally, the data were analyzed statistically. Results The peak MAPSE of the lateral mitral annulus in 3 different directions including points A, B and C[LAT-MAPSE-A (3.62±1.01)mm, LAT-MAPSE-B (3.95±1.04)mm, LAT-MAPSE-C (4.45±1.05)mm] were greater than those of the interventricular septum mitral annulus[SEPT-MAPSE-A (3.41±0.63)mm, SEPT-MAPSE-B (3.07±0.50)mm, SEPT-MAPSE-C (2.82±0.51)mm]. LAT-MAPSE-C and SEPT-MAPSE-A were the largest longitudinal excursions of mitral annulus. The differences were statistically significant in points B and C (P<0.05). There was no significant difference in point A (P>0.05). LAT-MAPSE-C was less than FAM-MAPSE[(6.06±1.35)mm]. There was a significant difference between them(P<0.05). Strong correlation was found between them(r=0.896, P<0.05). There were no significant differences in the time to peak of interventricular septal mitral annulus [SEPT-TTP-A (0.210±0.008)s, SEPT-TTP-B (0.213±0.008)s, SEPT-TTP-C (0.210±0.005)s] in directions including points A, B, C(P>0.05). There were no significant differences in time to peak of lateral mitral annulus[LAT-TTP-A(0.210±0.008)s, LAT-TTP-B(0.213±0.006)s, LAT-TTP-C(0.210±0.007)s] in directions inclucling points A, B, C(P>0.05). Conclusions Longitudinal systolic motion of fetal left ventricular wall during mid-late pregnancy has good synchronization. Longitudinal motion of fetal mitral annulus is a comprehensive movement of multiple directions and different degrees of displacement, with the movement perpendicular to the annulus as the maximum displacement direction. The displacement parameters of mitral annulus measured by STI can reflect the left ventricular longitudinal systolic function and have clinical application value in evaluating the left ventricular longitudinal systolic function of fetuses.