支气管源性囊肿CT与MRI表现和误诊分析

CT,MRI Findings and Misdiagnostic Analysis of Bronchogenic Cyst

目的探讨支气管源性囊肿的CT与MRI表现及误诊原因。方法回顾性分析经病理证实的61例BC患者的临床及影像资料。61例行CT平扫,39例行CT增强扫描;1例行MRI平扫,10例行MRI平扫及增强扫描。结果61例均为单发。52例呈类圆形,9例呈分叶形或不规则形。位于前纵隔26例,中纵隔2例,后纵隔20例,肺内、腹腔及肾上腺各3例,甲状腺、胸壁、颈部及胃部各1例。10例囊壁钙化。CT平扫11例呈水样密度(0~20 HU),50例呈软组织密度(21~80 HU)。MRI平扫5例T1WI呈稍高信号,4例呈等信号,2例呈稍低信号,11例T2WI呈高信号,6例DWI呈低信号,5例呈稍高信号,11例ADC序列呈高信号。MRI增强扫描无强化4例,边缘轻度强化6例。误诊为胸腺瘤14例,神经源性肿瘤8例,淋巴管瘤5例,肺癌、肺结核、胃肠道间质瘤、肾上腺腺瘤及畸胎瘤各1例。结论胸部不同部位支气管源囊肿影像学表现具有一定规律性,熟悉和掌握这些规律有助于BC诊断;而平扫CT值高于20 HU可能是影像误诊主要原因之一,增强意识和积累经验十分重要。

Objective To explore the CT and MRI findings of bronchogenic cyst(bronchogenie cyst,BC)and the cau-.ses of misdiagnosis.Methods Clinical and imaging data of 61 patients with pathologially confirmed bronchogenic cysts were retrospectively collected.61 patients underwent plain CT scans in which 39 underwent contrast-enhanced CT scans.1 patient received plain MR scans.10 patients received both plain and contrast-enhanced MR scans.Results All the 61 cases were solitary masses.52 roundish cases and 9 lobulated or irregular were recorded.26 cases were located in the anterior mediastinum,2 in the middle mediastinum,20 in the posterior mediastinum,each 3 in lung,abdominal cavity and adrenal gland,each 1 in thyroid gland,chest wall,neck and stomach.Calcification of cyst wall occurred in 10 cases.On plain CT scans 11 lesions showed water-like density(0-20 HU)and 50 showed soft tissue-like density(21-80 HU).On T,WI,five cases showed slightly hyperintense,4 showed isointense and 2 showed slightly hypointense.11 lesions on T,WI showed hyperintense.6 cases showed hypointense and 5 showed slightly hyperintense on DWI.11 cases on ADC sequence showed hyperintense.4 cases without enhancement and 6 with marginal mild enhancement were observed on contrast-enhanced MR scans.14 were misdiagnosed as thymoma,8 as neurogenic tumors,5 as lymphangiomas,each 1 as lung cancer,pulmonary tuberculosis,gastrointestinal stromal tumor,adrenal adenoma and teratoma.Conclusion There is a certain regularity in imaging findings of BC in chest,which is helpful to its diagnosis.Plain CT attenuation values above 20 HU may be one of the main causes of imaging misdiagnosis.It is significant to enhance awareness and accumulate experience.