From the Department of Neuroradiology (J.K., T.H., A.P., M.J., S.H., M.B.), Division of Child Neurology and Metabolic Medicine (A.Z., A.S.), Center for Child and Adolescent Medicine, Department of Neurology (G.S., W.W., M.W.), and Department of Neuroradiology (S.H.), Division of Experimental Radiology, Heidelberg University Hospital, Germany; Department of Neurology (J.M.H.), University of Michigan, Ann Arbor; Medical Faculty (M.J.), University of Tübingen; and German Cancer Consortium (DKTK) within the German Cancer Research Center (DKFZ) (W.W.), Heidelberg, Germany.
Neurology. 2019 Aug 13;93(7):e653-e664. doi: 10.1212/WNL.0000000000007945. Epub 2019 Jul 10.
To characterize and quantify peripheral nerve lesions and muscle degeneration in clinically, genetically, and electrophysiologically well-classified, nonpediatric patients with 5q-linked spinal muscular atrophy (SMA) by high-resolution magnetic resonance neurography (MRN).
Thirty-one adult patients with genetically confirmed 5q-linked SMA types II, IIIa, and IIIb and 31 age- and sex-matched healthy volunteers were prospectively investigated. All patients received neurologic, physiotherapeutic, and electrophysiologic assessments. MRN at 3.0T with anatomic coverage from the lumbosacral plexus and proximal thigh down to the tibiotalar joint was performed with dual-echo 2D relaxometry sequences with spectral fat saturation and a 3D T2-weighted inversion recovery sequence. Detailed quantification of nerve injury by morphometric and microstructural MRN markers and qualitative classification of fatty muscle degeneration were conducted.
Established clinical scores and compound muscle action potentials discriminated well between the 3 SMA types. MRN revealed that peroneal and tibial nerve cross-sectional area (CSA) at the thigh and lower leg level as well as spinal nerve CSA were markedly decreased throughout all 3 groups, indicating severe generalized peripheral nerve atrophy. While peroneal and tibial nerve T2 relaxation time was distinctly increased at all analyzed anatomic regions, the proton spin density was clearly decreased. Marked differences in fatty muscle degeneration were found between the 3 groups and for all analyzed compartments.
MRN detects and quantifies peripheral nerve involvement in SMA types II, IIIa, and IIIb with high sensitivity in vivo. Quantitative MRN parameters (T2 relaxation time proton spin density, CSA) might serve as novel imaging biomarkers in SMA to indicate early microstructural nerve tissue changes in response to treatment.
通过高分辨率磁共振神经成像（MRN）对临床、遗传和电生理分类明确的非儿科 5q 连锁脊髓性肌萎缩症（SMA）患者的周围神经病变和肌肉变性进行特征描述和定量分析。
前瞻性纳入 31 例经基因证实的 5q 连锁 SMA Ⅱ型、Ⅲa 型和Ⅲb 型成年患者和 31 名年龄和性别匹配的健康志愿者。所有患者均接受神经学、物理治疗和电生理评估。在 3.0T 磁共振扫描仪上使用双回波 2D 弛豫时间测量序列（带频谱脂肪饱和）和 3D T2 加权反转恢复序列进行腰骶丛和大腿近端至踝部的解剖覆盖范围的 MRN。通过形态计量学和微观结构的 MRN 标志物对神经损伤进行详细定量分析，并对脂肪肌肉变性进行定性分类。
既定的临床评分和复合肌肉动作电位可很好地区分 3 种 SMA 类型。MRN 显示，所有 3 组患者的大腿和小腿水平的腓总神经和胫神经横截面积（CSA）以及脊神经 CSA 均明显减小，表明存在严重的全身性周围神经萎缩。虽然所有分析的解剖区域的腓总神经和胫神经 T2 弛豫时间均明显增加，但质子自旋密度明显降低。在 3 组患者之间以及所有分析的节段中均发现明显的脂肪肌肉变性差异。
MRN 以高灵敏度在体内检测和定量 SMA Ⅱ型、Ⅲa 型和Ⅲb 型的周围神经受累。定量 MRN 参数（T2 弛豫时间、质子自旋密度、CSA）可能成为 SMA 的新型影像学生物标志物，以指示早期微观结构神经组织变化对治疗的反应。
