不同技术级别超声医师对离体猪横纹肌理化损伤模型超声定性诊断的局限性分析

Analysis of the impact of ultrasographer′s experience in diagnosing porcine striped muscle injury from thermal and chemical factors

目的探讨离体猪横纹肌遭热损伤、化学损伤后超声图像及光镜组织学变化,探讨不同技术级别超声医师对其定性诊断的局限性。方法分别以微波消融、无水乙酸注射损伤离体猪横纹肌作为实验模型,在预先不提供2种不同损伤区域的横纹肌组织病理结果的前提下,比较肌肉超声诊断及消融治疗亚专业组内3名不同技术级别超声医师对各实验组横纹肌超声图像特征独立判读的差异。结果正常离体猪横纹肌在分别遭受热损伤、化学损伤后,高频超声显示损伤区域的横纹肌纹理回声模糊,网络样结构消失,光镜下显示热损伤区域的肌纤维以变性、缩窄、碳化、断裂和脱失为主,而化学损伤区域的肌纤维则以肿胀、变粗、染色变淡、境界模糊、肌纤维间隙变窄或消失、肌纤维融合为特征。主治级别以上超声医师之间(主治医师在亚专业组工作5年,主任医师在亚专业组工作20年)对于描述热损伤及化学损伤组损伤区域的边界、形态、肌纹理清晰度的超声图像特征判读一致性高(Kappa=0.933、0.845、0.789;Kappa=0.790、0.935、0.865,P均<0.05);但主任医师、主治医师分别与住院医师(亚专业组工作1年)相比,描述热损伤组回声强度、肌纹理清晰度的判读一致性差(Kappa=0.323、0.297;Kappa=0.259、0.112)。描述化学损伤组肌纹理清晰度的判读一致性差(Kappa=0.253、0.070)。结论微波与无水乙酸损伤猪横纹肌可致肌纤维发生不同的组织学改变,高频超声虽能清晰显示不同因素致损后横纹肌超声图像特征,但独立定性诊断时受不同技术级别超声医师的主观影响产生判读差异,不能客观定量分析。长期从事肌肉超声诊断及消融治疗工作的主治级别以上医师所做出的超声特征判读一致性程度较高,更贴近其病理组织学变化。

Objective To investigate the ultrasonic and pathological features of porcine striped muscle injury from thermal and chemical factors respectively, and to analyze the limitation of ultrasound diagnosis given by doctors with different skill levels. Methods An experimental study using fresh porcine striped muscle in vitro was designed, where the injury were caused by microwave ablation（2 450 MHz） and Anhydrous acetic acid（99.8%） injection separately. Blind to pathologic results, the two-dimensiona sonograms taken from each model were analyzed by sonographers with different skill levels independently. Finally, the diagnoses were evaluated and compared among them. Results Two-dimensional sonograms showed distinct changes of the textures in both injury models, which was characterized as the disappearance of regular tissue structure. However, the corresponding histopathology revealed obvious differences between the two interventions on ultrasonograms. There was no statistical difference between chief physician and attending doctor（both of them had over 5-year experiences on skeletal muscle ultrasound） in identifying the ultrasonic features of boundary, shape and muscle texture（Kappa=0.933, 0.845, 0.789; Kappa=0.790, 0.935, 0.865, all P〈0.05）. Compared with residents′ diagnosis, there were significant differences in identifying the ultrasonic features of echo level and muscle texture in both injury models： Echo level in thermal injury group： chief physician vs residents, Kappa=0.323; attending doctor vs residents, Kappa=0.297. Texture feature in thermal injury group： chief physician vs residents, Kappa=0.259; attending doctor vs residents, Kappa=0.112. Texture feature in chemical injury group： chief physician vsresidents, Kappa=0.253; attending doctor vs residents, Kappa=0.070. Conclusions Microwave ablation and Anhydrous acetic acid can cause different histopathologic changes in correspondence with various features on two-dimensional sonograms. But ultrasonographers with different skill levels leads to significant variations in identification and qualitative diagnosis, which is impossible to be quantitatively analyzed. Chief physician and attending doctor can draw a consistent conclusion and demonstrate the ultrasounic characteristics in porcine striped muscle injury model from thermal or chemical factors.