Molina P L, Siegel M J, Glazer H S
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO 63110.
AJR Am J Roentgenol. 1990 Sep;155(3):495-500. doi: 10.2214/ajr.155.3.2117345.
MR imaging is an excellent technique for identifying and defining the extent of thymic tumors. T1-weighted spin-echo MR images (e.g., 600/15 [TR/TE]) best demonstrate tumor extent, and T2-weighted images (e.g., 2500/90 [TR/TE]) help differentiate "cystic" from solid thymic masses. Cyst formation and/or hemorrhage appear as areas of high signal intensity (greater than that of fat) on T2-weighted images. Focal areas of low signal intensity (less than that of muscle) correspond pathologically to fibrous capsules and septa, air, or calcification. In this report, the MR appearance of the normal thymus is reviewed briefly, and the gamut of abnormal thymic masses on MR is illustrated.
磁共振成像（MR）是识别和界定胸腺肿瘤范围的一项出色技术。T1加权自旋回波MR图像（例如，600/15 [重复时间/回波时间]）最能显示肿瘤范围，而T2加权图像（例如，2500/90 [重复时间/回波时间]）有助于区分“囊性”胸腺肿块与实性胸腺肿块。囊肿形成和/或出血在T2加权图像上表现为高信号强度区域（高于脂肪信号强度）。低信号强度的局灶性区域（低于肌肉信号强度）在病理上对应于纤维包膜和间隔、空气或钙化。在本报告中，将简要回顾正常胸腺的MR表现，并展示MR上各种异常胸腺肿块的情况。
