Zlatkin M B, Greenan T
Department of Radiology, Memorial Hospital, Hollywood, Florida 33021.
Magn Reson Q. 1992 Jun;8(2):65-96.
Magnetic resonance (MR) imaging has developed rapidly as a diagnostic tool in the evaluation of the wrist. In this article, the authors review simple high-resolution technique and appropriate surface coils to aid in wrist evaluation. Evaluation of the wrist is facilitated by an understanding of the anatomy of the carpal ligaments, the triangular fibrocartilage, and the carpal tunnel, and the anatomic features of the distal radioulnar joint. Triangular fibrocartilage tears, which represent an important cause of ulnar wrist pain, are well evaluated on MR. These appear as a linear band of increased signal on the short repetition time/echo time (TR/TE), proton density weighted spin echo, or gradient echo images. True tears should be differentiated from degenerative changes, which do not demonstrate increase in signal on T2 or T2* weighted images. With good technique, accuracies approaching 90% have been reported. MR is also useful in evaluating injuries of the interosseous ligaments and volar and dorsal radiocarpal ligaments and distal radioulnar joint instability. MR also has a role in evaluating the carpal tunnel syndrome. This is especially true with patients for whom symptoms suggest the diagnosis of carpal tunnel syndrome but for whom few objective findings exist. Findings suggestive of carpal tunnel syndrome include diffuse swelling of the median nerve, flattening of the median nerve at the level of the hamate, and increased signal of the median nerve on the long TR/TE images. MR is also indicated in avascular necrosis of the carpal bones and occult carpal fractures. MR is useful in evaluating bone tumors, particularly with regard to their extent. With the advent of more rapid scanning techniques, kinematic studies are feasible. For these, fast gradient echo techniques are employed and serial images are acquired during radial and ulnar deviation. These images may be helpful in observing integrity of intercarpal ligaments and evaluating dynamic instability. With proper attention to technique, and an understanding of wrist pathophysiology, MR is a valuable diagnostic tool.
磁共振（MR）成像作为腕关节评估的诊断工具已迅速发展。在本文中，作者回顾了有助于腕关节评估的简单高分辨率技术和合适的表面线圈。了解腕骨韧带、三角纤维软骨、腕管的解剖结构以及桡尺远侧关节的解剖特征有助于腕关节的评估。三角纤维软骨撕裂是尺侧腕部疼痛的重要原因，在MR上能得到很好的评估。在短重复时间/回波时间（TR/TE）、质子密度加权自旋回波或梯度回波图像上，这些撕裂表现为信号增强的线性带。真正的撕裂应与退变改变相鉴别，退变改变在T2或T2*加权图像上不会显示信号增强。采用良好的技术，报道的准确率接近90%。MR在评估骨间韧带、掌侧和背侧桡腕韧带损伤以及桡尺远侧关节不稳方面也很有用。MR在评估腕管综合征中也有作用。对于症状提示腕管综合征但客观发现较少的患者尤其如此。提示腕管综合征的表现包括正中神经弥漫性肿胀、钩骨水平处正中神经变平以及长TR/TE图像上正中神经信号增强。MR在腕骨缺血性坏死和隐匿性腕骨骨折的评估中也有指征。MR在评估骨肿瘤，特别是在评估其范围方面很有用。随着更快速扫描技术的出现，动态研究变得可行。对于这些研究，采用快速梯度回波技术，并在桡偏和尺偏过程中采集系列图像。这些图像可能有助于观察腕骨间韧带的完整性并评估动态不稳。通过适当关注技术并了解腕关节病理生理学，MR是一种有价值的诊断工具。
