[摘要]  目的：应用剪切波弹性成像技术（SWE）评估A型肉毒毒素注射咬肌瘦脸的治疗效果。方法：20例咬肌肥大患者，共40侧咬肌，接受A型肉毒毒素注射前后分别行二维超声及剪切波弹性成像检查，常规超声测量松弛状态和收缩状态下咬肌的厚度，SWE于两种状态下评估咬肌硬度，通过随访记录注射前、注射后1周、1月、3月、6月的各项指标，评价SWE在A型肉毒毒素注射咬肌中治疗效果评估的价值。结果：A型肉毒毒素注射后1周开始，无论是松弛状态还是收缩状态下咬肌厚度均减小，硬度减低，3月随访测量变化最明显，咬肌厚度明显缩小，松弛状态下平均缩小约22.2%±4.2%，收缩状态下平均缩小约22.8%±5.3%，肌硬度也明显下降，松弛状态下杨氏模量值平均缩小约19.5%±3.4%，收缩状态下平均缩小约60.4%±5.8%，6月时厚度及硬度开始恢复。结论：SWE用于动态观察咬肌的肌张力，结合其厚度变化，定量评价A型肉毒毒素注射瘦脸的药物疗效，为二次注射提供最佳的时间与剂量参考。

Objective: To assess the value of shear wave elastography(SWE) in the evaluation of type A botulinum toxin injection masseter for face-lift. Methods: 20 patients injected type A botulinum toxin in masseter. All the patients were examined by two-dimensional ultrasound and SWE. These two imagine methods measured the thickness and hardness of masseter under the relaxation state and forced occlusal status before injection, and after 1 week, 1 month, 3 months, 6 months. Result: Started 1 week after injection of type A botulinum toxin, the thickness and hardness of masseter muscle were decreased under both relaxation and occlusal condition. Those changes were obvious at 3 months, the mean reduction of relaxation masseter muscle thickness were 22.2%±4.2%, contraction thickness were 22.8%±5.3%, muscle strength was also significantly decreased, the mean reduction of relaxation strength were 19.5%±3.4%, contraction strength were 60.4%±5.8%, the thickness and hardness began to recover on 6 month. Conclusion: SWE and B-ultrasound could effectively reflect the reduction of muscle thickness and herdness after type A botulinum toxin injection. It could provide the best time and dose reference for the second injection.