目的 探讨肥大性下橄榄核变性 (hypertrophic olivary degeneration, HOD)影像学征象与病理学机制的关系，旨 在提高对本病认识和诊断水平。方法 回 顾性分析6例经临床及影像证实的肥大性 下橄榄核变性的临床特征及MRI表现，并 对HOD的临床特征、影像学特征与病理学 机制复习文献进行分析。结果 1例原发病 变位于一侧脑桥被盖束及对侧小脑齿状核 /小脑上脚，引起同侧HOD；2例原发病变 位于一侧桥脑被盖束，引起同侧HOD；2例 原发病变累及双侧桥脑被盖束，其中1例 引起双侧HOD，1例引起单侧HOD；1例原发 病变累及一侧小脑上脚，引起双侧HOD。 6例HOD的MRI均表现为延髓腹外侧局限性 体积增大，T2WI及FLAIR均呈高、稍高信 号；T1WI等信号者5例，稍高信号者1例。 结论 肥大性下橄榄核变性有较为特征性 的临床表现、发病部位及影像学表现，结 合其上游原发病变可作出诊断。

Objective To investigate the relationship between imaging properties of hypertrophic olivary degeneration (HOD) and its underlying pathologic mechanism, thus to enhance the cognition and clinical diagnosis performance. Methods 6 clinically and radiologically diagnosed cases of HOD were retrospectively observed according to their clinical features and MRI findings. Review the literature to analyze the corresponding clinical manifestations, MRI findings and pathologic mechanism. Results HOD was observed ipsilaterally with primary lesions when unilateral pontine central tegment tract was involved (2 cases) and unilateral pontine central tegment tract and contralateral dentate nucleus were both involved (1 case), while bilaterally when primary lesions involved unilateral superior cerebellar peduncle (1 case). Primary lesions of 2 cases involved bilateral pontine central tegment tract, one was observed bilateral HOD while the other unilaterally. All the 6 cases manifested as enlargement of ventral lateral part of medulla. The lesions presented hyper-intensity signal on T2weighted images and fluid-attenuated inversion-recovery (FLAIR) images. The T1weighted images revealed iso-intensity signal in 5 cases and slightly high signal in 1 case. Conclusion HOD has specific clinical and radiological features and usually occurs in particular anatomical sites. Correct diagnosis could be made if the primary lesions are taken into consideration.