Background: Wallerian degeneration (WD) of bilateral middle cerebellar peduncles (MCPs) can occur following pontine infarction, but its characteristics have not yet been clarified because of the low incidence. Thus, the present study discussed the clinical and radiological features to improve the awareness of this disease.
Methods: Clinical and radiological information from consecutive individuals diagnosed with WD of bilateral MCPs following pontine infarction in three hospitals over the past 4 years between October 2012 and October 2016 were retrospectively investigated and compared with a control group (patients with pontine infarction had no secondary WD).
Results:: This study involved 30 patients with WD of MCPs, with a detection rate of only 4.9%. The primary infarctions (χ2 =24.791, P = 0.001, vs. control group) were located in the paramedian pons in 21 cases (70.0%), and ventrolateral pons in nine cases (30.0%). WD of the MCPs was detected 8-24 weeks after pons infarction using conventional magnetic resonance imaging (MRI); all secondary WDs were asymptomatic and detected incidentally. All WD lesions exhibited bilateral, symmetrical, and boundary blurring on MRI. The signal features were hypointense on T1-weighted imaging, hyperintense on T2-weighted imaging and fluid-attenuated inversion recovery, and slightly hyperintense or isointense on diffusion-weighted imaging and apparent diffusion coefficient maps. Secondary brainstem atrophy was found in six (20.0%) cases. A Modified Rankin Scale score 0-2 was found in 10 (33.3%) cases and score >2 in 20 (66.7%) cases at 90 days after discharge, and the short-term prognosis was worse than that in control group (χ2 =12.814, P = 0.001).
Conclusions: Despite the rarity of bilateral and symmetrical lesions of MCPs, secondary WD should be highly suspected if these lesions occur within 6 months after pontine infarction, particularly paramedian pons. Conventional MRI appears to be a relatively sensitive method for detecting WD of MCPs, which might affect the short-term prognosis.
继发于脑桥梗塞的双侧小脑中脚华勒氏变性的临床及影像学特征摘要目的：探讨脑桥梗塞后继发性双侧小脑中脚（middle cerebellar peduncles，MCPs）华勒氏变性（Wallerian degeneration，WD）的临床及影像学特征。 方法：回顾性联合分析国内三家医院神经科过去4年间脑桥梗塞后双侧MCPs继发性WD患者的临床及影像学资料，并与对照组 (同期脑桥梗塞无继发性WD者）对比分析。 结果：本研究共纳入30例WD患者，仅占脑桥梗塞的4.9%，其中原发脑桥梗塞位于旁正中21例（70.0%）、腹外侧9例（30.0%），病变部位构成比与对照组有显著差异（χ2=24.791,P = 0.001）。常规MRI发现WD距原发脑桥梗塞的时间不等（8-24周），但均无临床症状。其在MRI上表现为双侧对称性类圆形病变，边界模糊，信号特点为T1低信号、T2及Flair高信号、DWI及ADC轻度高信号或等信号，另外6例（20.0%）患者伴同侧下位脑干萎缩。随访发现病例组出院90天时mRS评分（0-2分）者占10例 （33.3%），2分以上者占20例 （66.7%），其短期不良预后显著高于对照组 (χ2=12.814,P = 0.001)。 结论：尽管双侧MCPs对称性病变罕见，但如出现在脑桥梗塞后6个月之内，临床应高度怀疑继发性WD。常规MRI检查是诊断该病较为敏感的方法。另外，该变性可能与脑桥卒中后短期预后不良相关。.
Keywords: Magnetic Resonance Imaging; Middle Cerebellar Peduncles; Neurological Prognosis; Pontine Infarction; Wallerian Degeneration.