Kono M, Adachi S, Kusumoto M, Sakai E
Department of Radiology, Kobe University School of Medicine, Japan.
J Thorac Imaging. 1993 Winter;8(1):18-26.
Magnetic resonance (MR) imaging has both advantages and disadvantages in its application in lung cancer staging. Because of its ability to provide superior contrast resolution and to display structures in many planes, MR imaging is better than computed tomography (CT) for the detection of mediastinal and chest wall invasion. MR imaging also is more sensitive than CT for detection of hilar and mediastinal lymph node enlargement. Multiplanar T1- and T2-weighted images are optimal for differentiating lymph nodes from large vessels without the need for contrast enhancement; in these cases administration of Gd-DTPA provides no more information than plain MR images. MR studies should be used for examining patients with suspected mediastinal or chest wall invasion and those who have equivocal hilar or mediastinal adenopathy. The shortening effect of Gd-DTPA on the T1 value results in a high signal. This effect is dependent upon both the perfusion and diffusion of the contrast agent and the amount of extracellular fluid. The distribution of Gd-DTPA is similar to that of iodinated water-soluble contrast media. Gd-DTPA examination should be tailored to provide information regarding blood flow, vascularity, and permeability, none of which is easily appreciated on CT or plain MR images. Applications for which Gd-DTPA enhancement may be helpful include differentiating between malignant and benign pulmonary masses, differentiating between hilar lung cancer and peripheral postobstructive atlectasis or pneumonia, determining therapeutic effect after radiation therapy, and differentiating between recurrent or residual tumor and radiation pneumonitis.
磁共振（MR）成像在肺癌分期中的应用既有优点也有缺点。由于其能够提供卓越的对比分辨率并在多个平面显示结构，在检测纵隔和胸壁侵犯方面，MR成像比计算机断层扫描（CT）更具优势。在检测肺门和纵隔淋巴结肿大方面，MR成像也比CT更敏感。多平面T1加权和T2加权图像对于区分淋巴结和大血管最为理想，无需对比增强；在这些情况下，给予钆喷酸葡胺（Gd-DTPA）所提供的信息并不比普通MR图像更多。MR研究应用于检查疑似纵隔或胸壁侵犯的患者以及肺门或纵隔淋巴结病不明确的患者。Gd-DTPA对T1值的缩短效应导致高信号。这种效应取决于造影剂的灌注和扩散以及细胞外液的量。Gd-DTPA的分布与碘化水溶性造影剂相似。Gd-DTPA检查应根据具体情况进行，以提供有关血流、血管分布和通透性的信息，而这些在CT或普通MR图像上均不易明确。Gd-DTPA增强可能有帮助的应用包括鉴别恶性和良性肺肿块、鉴别肺门肺癌与周围阻塞性肺不张或肺炎、确定放疗后的治疗效果以及鉴别复发或残留肿瘤与放射性肺炎。
