Abstract: Objective　To investigate the reversed halo sign （RHS） on chest high-resolution CT（HRCT） scan findings and identify the distinguishing features among the patients with various causes.Methods　We retrospectively studied the chest HRCT scans of patients who were admitted in Respiratory Department of Hang Zhou Red Cross Hospital from 2013 to 2015.Clinical data of all the 17 cases with RHS on HRCT were collected.Two chest radiologists reviewed the HRCT scans with RHS and described the appearance,respectively.The CT scan findings were determined by consensus.The morphologic characteristics,number of lesions,focis characters and accompanied lesions of RHS were recorded.Results　There were 9 cases of infectious diseases （invasive pulmonary aspergillosis 1 case,pulmonary tuberculosis 4 cases,pneumonia 4 cases） and 8 cases of noninfectious diseases （cryptogenic organizing pneumonia 1 case,pneumonia associated with systemic lupus erythematosus 1 case,pulmonary sarcoidosis 1 case,pulmonary adenocarcinoma 1 cases,lymphoma 1 case,vasculitides 1 case,organized pneumonia after infectious 2 cases）.There were 13 cases with smooth wall and 4 cases with nodular wall.There were multiple miliary nodules on the walls or inside the halos in all patients with active pulmonary tuberculosis,while no nodules in other infectious and noninfectious diseases.Conclusion　The presence of small nodules on the wall or within the PHS highly suggested granulomatous diseases,especially active pulmonary tuberculosis rather than COP or other pulmonary infectious and noninfectious diseases.

Key words: Lung diseases, Tomography,spiral computed, Thorax, Reversed

摘要： 目的　分析17例不同疾病患者胸部高分辨CT的反晕征特点,以提高对可能产生反晕征的不同病因的鉴别能力。方法　回顾性分析2013—2015年在杭州市红十字会医院呼吸科就诊的17例胸部高分辨CT表现为反晕征患者的临床资料，由2位放射科医生分别独立阅读CT影像结果，并对结果进行描述，且意见一致。记录反晕征的形态、数量、病灶特点及其他伴随病变。结果　17例患者中感染性疾病9例（侵袭性肺曲霉菌病1例、肺结核4例、肺炎4例），非感染性疾病8例（隐源性机化性肺炎1例、系统性红斑狼疮肺炎1例、结节病1例、肺腺癌1例、淋巴瘤1例、血管炎1例、感染后机化性肺炎2例）。反晕征壁光滑 13例，反晕征壁内或周围有结节4例。活动性肺结核患者反晕征壁内或周围均可见多发粟粒状小结节，其他感染性疾病或非感染性疾病所致反晕征壁内或周围均未见有小结节。结论　反晕征壁内或周围有小结节多提示肉芽肿性疾病，肺结核可能性大，而不应考虑隐源性机化性肺炎或其他感染性肺疾病及非感染性肺疾病。

关键词: 肺疾病, 体层摄影术,螺旋计算机, 胸部, 反晕征