先天性支气管囊肿的影像诊断

目的：探讨先天性支气管囊肿的影像学表现特征。方法：回顾性分析24例经手术病理证实的先天性支气管囊肿的 CT 和 MRI 图像。18例行 CT 增强扫描，6例行 CT 平扫，其中5例加行 MRI 平扫，2例行 PET-CT 扫描。结果：24例先天性支气管囊肿包括肺内型5例和纵隔型19例。病灶呈圆形、椭圆形、“D”字形或分叶形；11例病变位于典型部位，包括右侧气管7例和隆突下4例；13例病变位于不典型部位，包括前纵隔4例、食管旁2例、脊柱旁1例、心包旁1例和两下肺5例。以 CT 值20 HU 为囊、实性病变分界值，5例为囊性（CT 值＜20 HU），19例为实性（CT 值＞20 HU）；边缘钙化3例；内部分层4例。病变 T1 WI 呈低、等或高信号，T2 WI 均呈显著高信号，3例显示分层。24例中误诊10例，术前诊断符合率为58．3％。结论：先天性支气管囊肿的 CT 和 MRI 表现特征有助于其诊断和鉴别诊断，并指导进一步的治疗。

Imaging diagnosis of congenital bronchial cyst

Objective:To study the imaging features of congenital bronchial cyst.Methods:The clinical,CT and MRI materials of 24 patients with surgery and pathology proved congenital bronchial cysts were retrospectively analyzed.18 pa-tients underwent pre-and post-contrast CT scanning and 6 patients only had plain CT.5 patients had additional MRI and 2 patients had PET-CT.Results:Of the 24 patients,there were intrapulmonary bronchogenic cysts (5 patients)and mediasti-nal bronchogenic cysts (19 patients).Bronchogenic cysts can demonstrate as round,ovoid,"D"shape and lobulated lesions. 11 lesions located at"typical position"including right side of trachea (7 cases)and infra-carina (4 cases).13 lesions located at "atypical position"including anterior mediastinum (4 cases),para-esophagus (2 cases),para-spinal (1 case)para-pericar-dium (1 case)and the lower lobe of lung (5 cases).Taking 20HU as the threshold deferentiating cystic and solid density, there were 5 lesions having cystic density and 19 lesions showed solid density.Marginal calcification was found in 3 lesions and fluid to fluid level was found in 4 lesions.On MRI,the cysts were iso-or hypo-intensity on T1 WI and hyperintensity on T2 WI.10 of the 24 patients were misdiagnosed before surgery,the diagnosis accuracy was 58.3%.Conclusion:There were certain imaging characteristics of congenital bronchial cyst,which were valuable for diagnosis and guidance of treatment.