| Purpose:To evaluate the value of subclinical myocardial dysfunction after radiotherapy in patients with thoracic tumor by two-dimensional speckle tracking imaging,and to explore the dose-effect relationship and the regional distribution characteristics of myocardial injury,so as to provide the basis for cardiac protective treatment.Materials and methods:We selected 51 patients with thoracic tumor,undergoing the first chest radiotherapy with radiation field involving the heart in our hospital from November2019 to December 2020.38 patients finally met the image requirements and completed follow-up,including 14 males and 24 females,aged 30-69 years,had an average age of(52.46±9.60)years,15 breast cancer(13 left,2 right),7 esophageal carcinoma,16 lung cancer(14 left,2 right),9 patients were concomitant with chemotherapy(without anthracyclines and trastuzumab).According to the course of radiotherapy,The 38 patients were divided into three group: Group A: before radiotherapy(control group);Group B: immediately after radiotherapy;Group C: 3 months after radiotherapy.A comprehensive transthoracic echocardiogram was performed at baseline,immediately after RT and 3 months after radiotherapy,Two-dimensional echocardiographic parameters were measured under standard sections:AO、LA、RVIDd、IVSd、LVIDd、LVPWd、LVEDV、LVESV、LVEF、FAC、TAPSE、E、A、E/A、e’(m/l)、E/e’、s’.And obtain 2D grayscale dynamic images of 6 standard sections(mitral valve,papillary muscle,apical short-axis section,and apical twochamber,three-chamber,and four-chamber sections),the frame rate is greater than 100 frames / second,and each view records more than 3 cardiac cycles.Processing acquired images used QLAB 9.0 software CMQ program.We measure GLS、GRS、GCS and GLS in every segments,and calculate the change in GLS from baseline to 3 months after radiotherapy(△GLS).According to the coronary artery supply region corresponding to the left ventricular myocardium,we calculate territorial longitudinal strain(TLS LAD,TLS Cx and TLS RCA).Result:1.Conventional echocardiography parameters comparisonCompared with the baseline values before radiotherapy,the differences of LVIDd、RVIDd、LVEDV、LVESV、IVSd parameters were no statistical significance in the course of radiotherapy(P>0.05).Compared with the baseline,LVEF showed significance differences after radiotherapy and 3 months after radiotherapy(P<0.05).Compared with the baseline,E、A、E/A、e’(m)、e’(l)、E/e’、TAPSE、FAC、s’ showed no significance differences after radiotherapy and 3 months after radiotherapy(P>0.05),But in the course of radiotherapy,e ’(m)and e’(l)show a downward trend,E/ e ’shows an upward trend.2.2D-STI parameters comparisonCompared with the baseline,BAS、BA、MA、MAS、APA showed significance differences after radiotherapy and 3 months after radiotherapy(P<0.05).Compared with the baseline,GLS showed significance differences after radiotherapy(P<0.05)and decreased significantly 3 months after radiotherapy(P<0.01).Compared with the baseline,TLS LAD showed significance differences after radiotherapy(P<0.05)and decreased significantly 3 months after radiotherapy(P<0.01).3.Correlation analysisCorrelation analysis showed positive correlation of △GLS with MHD(r=0.669,P<0.05),also showed positive correlation of △GLS with V30(r=0.729,P<0.05).4.The value of echocardiography in predicting subclinical myocardial dysfunction after radiotherapy.The receiver operating characteristis curve showed using GLS、TLS LAD、LVEF to predict the subclinical myocardial dysfunction 3 months after radiotherapy.In order of the area under the curve: TLS LAD(0.851)>GLS(0.815)>LVEF(0.699).Conclusion:1.2D-STI can early detect radiation-induced subclinical myocardial dysfunction,the left ventricular systolic function is gradually decreased with the increase of radiotherapy dose.2.GLS and TLS LAD can detect radiation-induced subclinical myocardial dysfunction at an early stage,and radiation-induced cardiac injuries have regional distribution characteristics. |
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