Archer John Matthew, Ahuja Jitesh, Strange Chad D, Shroff Girish S, Gladish Gregory W, Sabloff Bradley S, Truong Mylene T
Department of Thoracic Imaging, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Mediastinum. 2023 May 8;7:27. doi: 10.21037/med-22-53. eCollection 2023.
A wide variety of neoplastic and nonneoplastic conditions occur in the mediastinum. Imaging plays a central role in the evaluation of mediastinal pathologies and their mimics. Localization of a mediastinal lesion to a compartment and characterization of morphology, density/signal intensity, enhancement, and mass effect on neighboring structures can help narrow the differentials. The International Thymic Malignancy Interest Group (ITMIG) established a cross-sectional imaging-derived and anatomy-based classification system for mediastinal compartments, comprising the prevascular (anterior), visceral (middle), and paravertebral (posterior) compartments. Cross-sectional imaging is integral in the evaluation of mediastinal lesions. Computed tomography (CT) and magnetic resonance imaging (MRI) are useful to characterize mediastinal lesions detected on radiography. Advantages of CT include its widespread availability, fast acquisition time, relatively low cost, and ability to detect calcium. Advantages of MRI include the lack of radiation exposure, superior soft tissue contrast resolution to detect invasion of the mass across tissue planes, including the chest wall and diaphragm, involvement of neurovascular structures, and the potential for dynamic sequences during free-breathing or cinematic cardiac gating to assess motion of the mass relative to adjacent structures. MRI is superior to CT in the differentiation of cystic from solid lesions and in the detection of fat to differentiate thymic hyperplasia from thymic malignancy.
纵隔可发生各种各样的肿瘤性和非肿瘤性疾病。影像学在纵隔病变及其类似病变的评估中起着核心作用。将纵隔病变定位到某个分区，并对其形态、密度/信号强度、强化情况以及对邻近结构的占位效应进行特征描述，有助于缩小鉴别诊断范围。国际胸腺恶性肿瘤研究小组（ITMIG）建立了一种基于横断面成像和解剖学的纵隔分区分类系统，包括血管前（前）、内脏（中）和椎旁（后）分区。横断面成像在纵隔病变评估中不可或缺。计算机断层扫描（CT）和磁共振成像（MRI）有助于对X线检查发现的纵隔病变进行特征描述。CT的优点包括广泛可用、采集时间短、成本相对较低以及能够检测钙化。MRI的优点包括无辐射暴露、软组织对比分辨率高，能够检测肿块跨越组织层面的侵犯情况，包括胸壁和膈肌、神经血管结构受累情况，以及在自由呼吸或电影式心脏门控期间进行动态序列成像以评估肿块相对于相邻结构的运动情况。在区分囊性病变与实性病变以及检测脂肪以鉴别胸腺增生与胸腺恶性肿瘤方面，MRI优于CT。
