应变率成像评价胸部放疗对心脏的早期损伤

目的采用应变率成像(SRI)分析左室壁应变率特点,评价其在胸部放疗对心脏早期损伤方面的应用。方法40例胸部全程放疗患者按照放疗进程分为三组:A组:放疗前1～3天;B组:放疗时间2.5～3周、照射剂量26～30Gy;C组:放疗时间5～6周(放疗结束时)、照射剂量50～60Gy。比较3组常规超声心动图测值及前壁、下壁、前间隔、后壁的基底段及中间段8个位点的收缩期最大应变率(s)、舒张早期最大应变率(e)、房缩期应变率(a),取三个心动周期的平均值。结果C组前壁、前间隔、后壁各节段的s、e较A组明显减低且差异有显著性(P<0.01);B组前壁、前间隔、后壁各节段的s、e较A组略减低但差异无显著性(P>0.05);下壁各节段的s、e在各组之间差异无显著性(P>0.05);C组左室舒张功能(E/A)较A组减低有显著性差异(P<0.01);B组的E/A较A组略减低但无显著性差异(P>0.05)。结论应变率成像可定量分析胸部放疗患者心脏的早期损伤。

Strain rate imaging in early assessment of thoracic radiotherapy-induced myocardial damage

Objective To evaluate the value of strain rate imaging (SRI) in detecting early thoracic radiotherapy-induced myocardial damage by studying the characteristics of strain rate in the left ventricular walls. Methods SRI and conventional echocardiographic parameters were performed in 40 patients with thoracic radiotherapy. According to the process of radiotherapy, the patients were divided into three groups: group A: 1-3 days before the radiation treatment; group B: radiotherapy time was 2.5-3 weeks, radiotherapy dose was 26-30 Gy; group C: radiotherapy time was 5-6 weeks, radiotherapy dose was 50-60 Gy. SRI was obtained through the apical window in 2-chamber and long apical views to measure s (systolic strain rate), e (early diastolic strain rate), a (later diastolic strain rate) respectively. Results s, e of group C in anterior wall, anterior septum, posterior wall were significantly lower than those in group A (P<0.01); s, e of group B in anterior wall, anterior septum, posterior wall were lower than those in group A, which had no significant difference (P>0.05); s, e of inferior wall in all groups had no significant difference (P>0.05). Left ventricular diastolic function (E/A) of group C was significantly lower than that in group A (P<0.01); There was no significant difference of E/A between group B and group A(P>0.05). Conclusion SRI can quantitatively detect myocardial damage in patients with thoracic radiotherapy.