Templeton P A, Zerhouni E A
Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland.
Radiol Clin North Am. 1989 Nov;27(6):1099-111.
CT remains the modality of choice for evaluating patients with a thoracic malignancy. In specific cases MR imaging can provide useful information that cannot be obtained with CT, and thus is useful as a problem solving tool. Advantages of MR imaging include superb demonstration of vessels and vessel/mass relationships, direct multiplanar imaging capability, and the potential for tissue characterization. MR imaging is useful in staging the patient with lung cancer when vascular or mediastinal invasion is in question. Its specific applications in surgical planning include the question of chest wall invasion, brachial plexus involvement, and transgression of the diaphragm, pericardium, or lung apex. Multiplanar imaging is useful in radiation therapy planning, displaying lesion extent in a coronal or sagittal format rather than on multiple axial images. Multiplanar capability also resolves problem areas for CT such as the aortopulmonic window, subcarinal region, and lesions at the cervicothoracic or thoracoabdominal junction. Structures such as the trachea and superior vena cava can be evaluated in their plane of anatomic orientation. Routine spin-echo and fast (GRASS) imaging of mediastinal vessels is useful in the evaluation of venous thrombosis as a result of catheters or tumors. The diagnosis and follow-up are obtained without the use of intravenous contrast material or radiation. When CT cannot evaluate vessels adequately because of surgical clip artifacts or postoperative distortion of anatomy, MR imaging is useful in the determination of vessel patency as well as identification of tumor recurrence. Cardiac masses are very well demonstrated by MR imaging. A unique feature of MR imaging is its potential for tissue characterization and ability to assess disease activity. Lymphoma evaluation is an active area of research. MR imaging can evaluate the radiated patient for tumor response and recurrence. Fibrous tissue remains of low signal intensity on T2-weighted images, whereas tumor has increased signal intensity. MR imaging may detect tumor recurrence before an increase in the size of a residual lymphoma mass and before clinical recurrence is evident. The area of increased signal can also serve as a guide to the appropriate site for biopsy to confirm recurrence. In addition, MR imaging can help characterize some adrenal and liver masses, potentially helping to avoid more invasive diagnostic procedures. At the current time MR spectroscopy does not have a clinical role in thoracic malignancies, but it may be a powerful tool in the future for diagnosis and management.
CT仍然是评估胸部恶性肿瘤患者的首选方式。在特定情况下，磁共振成像（MR成像）可以提供CT无法获得的有用信息，因此作为一种解决问题的工具很有用。MR成像的优点包括对血管及血管与肿块关系的出色显示、直接多平面成像能力以及组织特征分析的潜力。当怀疑有血管或纵隔侵犯时，MR成像对肺癌患者的分期很有用。其在手术规划中的具体应用包括胸壁侵犯、臂丛神经受累以及膈肌、心包或肺尖侵犯的问题。多平面成像在放射治疗规划中很有用，以冠状面或矢状面形式而非多个轴位图像显示病变范围。多平面能力还解决了CT的一些问题区域，如主肺动脉窗、隆突下区域以及颈胸或胸腹交界处的病变。气管和上腔静脉等结构可以在其解剖方向平面上进行评估。纵隔血管的常规自旋回波和快速（梯度回波稳态采集序列，GRASS）成像对评估因导管或肿瘤导致的静脉血栓形成很有用。无需使用静脉造影剂或辐射即可进行诊断和随访。当由于手术夹伪影或术后解剖结构变形导致CT无法充分评估血管时，MR成像在确定血管通畅性以及识别肿瘤复发方面很有用。心脏肿块在MR成像中显示得非常好。MR成像的一个独特特征是其组织特征分析的潜力以及评估疾病活动的能力。淋巴瘤评估是一个活跃的研究领域。MR成像可以评估接受放疗的患者的肿瘤反应和复发情况。纤维组织在T2加权图像上仍呈低信号强度，而肿瘤信号强度增加。MR成像可能在残留淋巴瘤肿块大小增加之前以及临床复发明显之前检测到肿瘤复发。信号增加的区域也可作为指导活检合适部位以确认复发的依据。此外，MR成像可以帮助对一些肾上腺和肝脏肿块进行特征分析，可能有助于避免更具侵入性的诊断程序。目前，磁共振波谱在胸部恶性肿瘤中没有临床作用，但它未来可能成为诊断和管理的有力工具。
