MRI在前纵隔等密度囊肿与低危型胸腺瘤鉴别诊断中的价值  

The Value of MRI in Differential Diagnosis between Isodensity Cyst in Anterior Mediastinum and Low-Risk Thymoma

作　　者：叶爱华[1] 苗焕民[1] 马新星[1] 胡粟[1] YE Aihua;MIAO Huanmin;MA Xinxing(Department of Radiology,The First Affiliated Hospital of Soochow University,Suzhou,Jiangsu Province 215006,P.R.China)

机构地区：[1]苏州大学附属第一医院放射科,215006

出　　处：《临床放射学杂志》2022年第4期639-643,共5页Journal of Clinical Radiology

摘　　要：目的 探讨MRI定量特征在前纵隔等密度囊肿与低危型胸腺瘤鉴别诊断中的价值。方法 回顾性分析经手术病理确诊的25例前纵隔等密度囊肿与18例低危型胸腺瘤的CT和MRI征象,分析病灶的形态、有无钙化、有无分隔、内部密度及信号特征等;测量并计算病灶各定量参数,包括长径/短径、平扫CT值、CT强化程度、MRI各序列相对值[相对T_(1)值(rT_(1))、相对T_(2)值(rT_(2))、相对表观扩散系数(rADC)、相对T_(1)增强值(rCE)]、角度变化绝对值,对两种类型病变的征象及定量参数进行统计学分析。结果 等密度囊肿和低危型胸腺瘤平扫CT值无统计学差异,长径/短径、CT强化程度、rT_(1)、rT_(2)、rADC、rCE、角度变化绝对值之间的差异均具有统计学意义(P<0.05)。等密度囊肿多表现为无或轻度强化,等或短T_(1)、长T_(2)信号,无扩散受限,且其角度随纵隔形态的改变而明显变化。MRI对等密度囊肿的诊断符合率明显高于CT(P<0.05)。结论 MRI对前纵隔等密度囊肿与低危型胸腺瘤具有较高的鉴别诊断价值,结合T_(1)、T_(2)信号和T_(1)增强信号有助于提高诊断准确率。Objective To investigate the value of MRI quantitative features for differentiating isodensity cyst in anterior mediastinum and low-risk thymoma.Methods Pathologically proved isodensity cysts in anterior mediastinum(n=25) and low-risk thymomas(n=18) were retrospectively reviewed.CT and MRI findings of them were compared with each other.The shape,calcification,separation,internal density and signal features of the lesions were analyzed.Quantitative parameters were measured and calculated respectively,including ratio of long diameter to short diameter,the value of plain CT scan,the degree of CT contrast enhancement,relative signal ratio of each MRI sequence(rT_(1)、rT_(2)、rADC、rCE),and absolute value of angular variation.The features and quantitative data obtained were analyzed statistically.Results The ratio of long diameter to short diameter,the degree of CT contrast enhancement,rT_(1)、rT_(2)、rADC、rCE,and absolute value of angular variation were with statistical significant difference between isodensity cysts and low-risk thymomas(P﹤0.05),except for the value of plain CT scan.Isodensity cysts showed no or mild enhancement,iso-or-hyperintensity on T_(1)WI,hyperintensity on T_(2)WI obviously,no restricted diffusion,and their angles changed significantly following the changes in mediastinal shape.Conclusion The MRI provide effective evidences to distinguish isodensity cyst in anterior mediastinum from low-risk thymoma.The combination of T_(1),T_(2) signal and T_(1) enhanced signal has contributed to improve the diagnostic accuracy.

关 键 词：前纵隔 等密度囊肿 低危型胸腺瘤 体层摄影术 X线计算机 磁共振成像 

分 类 号：R736.3[医药卫生—肿瘤] R445.2[医药卫生—临床医学]