摘要目的:探讨超声对英夫利西单抗治疗儿童克罗恩病维持期继发性失应答的诊断价值。方法:回顾性分析2017年1月至2021年12月在首都医科大学附属北京儿童医院接受英夫利西单抗治疗且临床应答的克罗恩病患儿51例，并在维持期观察是否有继发性失应答的发生。收集治疗第14周超声检查结果，以了解超声检查肠壁及肠周愈合情况与继发性失应答的相关性。结果:治疗随访至54周，51例患儿中共15例(29.4%)发生继发性失应答。相较于持续应答患儿，继发性失应答患儿在治疗第14周时肠壁更厚[5.0(3.8，6.0)mm比3.0(2.0，4.0)mm， P<0.001]，肠壁分层结构消失比例更高[8/15(53.33%)比3/36(8.33%)， P<0.001]，肠壁厚度>3.0 mm时，敏感性为0.955，特异性为0.483。肠壁分层是否清晰诊断继发性失应答的敏感性为0.727，特异性为0.825。联合诊断继发性失应答的敏感性为0.933，特异性为0.611。 结论:克罗恩病儿童英夫利西单抗治疗第14周超声测量肠壁厚度>3.0 mm和肠壁层次不清晰，可为药物继发性失应答诊断提供重要信息。

abstractsObjective:To investigate the value of ultrasound in the diagnosis of secondary loss of response in children with Crohn′s disease at maintenance stage treated with Infliximab.Methods:From January 2017 to December 2021, 51 children with Crohn′s disease who received Infliximab treatment and clinical response in the Beijing Children′s Hospital Affiliated to Capital Medical University were retrospectively analyzed, and whether there was secondary loss of response during the maintenance period was observed. The ultrasound examination results at the 14th week of treatment were collected to understand the correlation between ultrasound examination of intestinal wall and peri-intestinal healing and secondary loss of response.Results:A total of 15 out of 51 patients (29.4%) experienced secondary loss of response during treatment follow-up up to 54 weeks. Compared to children with continuous response, children with secondary loss of response had a thicker intestinal wall at week 14 of treatment [5.0 (3.8, 6.0)mm compared to 3.0 (2.0, 4.0)mm, P<0.001], and a higher proportion of intestinal wall stratified structure disappearance [8/15 (53.33%) compared to 3/36 (8.33%), P<0.001]. When intestinal wall thickness>3.0 mm, the sensitivity was 0.955, and the specificity was 0.483. The sensitivity and specificity of clear diagnosis of secondary loss of response in intestinal wall stratification were 0.727 and 0.825, respectively. The sensitivity and specificity of combined diagnosis for secondary loss of response were 0.933 and 0.611, respectively. Conclusions:At the 14th week of treatment with Infliximab in children with Crohn′s disease, the thickness of intestinal wall measured by ultrasound being more than 3.0 mm and the disappearance of intestinal wall statified structure provide important information for the diagnosis of secondary loss of response.