目的 分析脊髓性肌萎缩症(spinal muscular atrophy,SMA)患儿大腿肌肉常规MRI影像表现特点及其临床应用价值.材料与方法 以2022年1月至2022年8月在华中科技大学同济医学院附属武汉儿童医院经基因确诊并进行MRI检查的37例(Ⅰ型5例,Ⅱ型21例,Ⅲ型11例)SMA患儿为研究对象,回顾性分析不同临床分型SMA患儿大腿肌肉MRI影像表现及临床资料.采用改良版Mercuri分级对右侧大腿肌肉脂肪浸润程度进行半定量评估,采用Spearman相关性分析,将脂肪浸润总分与汉默史密斯功能运动-扩展量表(Hammersmith Functional Motor Scale Expanded,HFMSE)评分、病程及存活运动神经元2(survival motor neuron 2,SMN2)基因拷贝数进行相关性分析.结果 SMA患儿表现为双侧大腿肌肉形态学改变,肌肉内部和(或)周围有点状、条状和(或)片状脂肪信号影,致肌肉呈"网状"和(或)"岛屿状";Ⅰ型SMA以肌肉萎缩为主,Ⅱ型SMA伴有肌肉肥大,Ⅲ型SMA以脂肪浸润为主;Mercuri脂肪浸润评分显示股四头肌(肌直肌、股外侧肌、股中间肌及肌内侧肌)、缝匠肌、大收肌、股薄肌受累程度较重,其中缝匠肌的Mercuri评分最高,而长收肌、股二头肌长头、半腱肌和半膜肌受累程度较轻,其中长收肌的Mercuri评分最低,并且明显低于其他肌肉;Ⅲ型SMA患儿肌肉脂肪浸润程度与HFMSE运动功能评分呈负相关(r=−0.917,P<0.001),所有SMA患儿肌肉脂肪浸润程度均与病程呈正相关(r=0.772,P<0.001).结论 SMA患儿常规MRI表现为肌肉萎缩和脂肪浸润为主,且脂肪浸润是进行性的,不同临床表型SMA患儿肌肉受累模式及严重程度不同.此外,SMA累及肌肉是有选择性的,存在相对肌肉保留模式.MRI能可视化评估SMA患儿肌肉受累情况,并与临床指标具有良好的相关性,是一个有潜力的生物标志物.
MRI features and clinical correlation analysis of thigh muscle in children with spinal muscular atrophy
Objective:To analyze the imaging features and clinical application value of MRI of thigh muscles in children with spinal muscular atrophy (SMA). Material and Methods:A total of 37 children with SMA (5 patients with type Ⅰ,21 patients with type Ⅱ,11 patients with type Ⅲ) who were genetically diagnosed and underwent MRI examination in Wuhan Children's Hospital Affiliated to Tongji Medical College Huazhong University of Science and Technology from January 2022 to August 2022 were selected as the study objects. The MRI manifestations and clinical data of thigh muscles in children with different clinical types of SMA were retrospectively analyzed. The degree of muscle fat infiltration in the right thigh was evaluated semi-quantitatively by modified Mercuri grading and Spearman correlation analysis. Total fat infiltration score was compared with Hammersmith Functional Motor Scale Expanded (HFMSE) score,disease duration and survival motor neuron 2 (SMN2) gene copy number correlation analysis.Results:The children with SMA showed the morphological changes of bilateral thigh muscles,and there were dots,strips and (or) flaky fat signal shadows in and around the muscles,resulting in "network" and (or) "island" shape of muscles. Type I SMA is mainly associated with muscle atrophy,type Ⅱ SMA is associated with muscle hypertrophy,and type Ⅲ SMA is mainly associated with fat infiltration. Mercuri fat infiltration score showed that quadriceps femoris (musculus rectus,musculus lateralis,musculus intermedius and musculus medius),sartorius,adductor magnus and musculus gracilis were more heavily involved,among which sartorius had the highest Mercuri score,while the adductor longus,musculus biceps femoris longus,musculus semitendinosus and musculus semimemmembranus were less involved. The Mercuri score of the adductor longus was the lowest,and significantly lower than that of other muscles. The degree of muscle fat infiltration in children with type Ⅲ SMA was negatively correlated with the motor function score of HFMSE (r=−0.917,P<0.001),and the degree of muscle fat infiltration was positively correlated with the course of disease in all children with SMA (r=0.772,P<0.001). Conclusions:The conventional MRI findings of children with SMA are mainly muscle atrophy and fat infiltration,and the fat infiltration is progressive,and the muscle involvement pattern and severity of children with SMA are different in different clinical phenotypes. In addition,SMA muscle involvement is selective,with relative muscle retention patterns. MRI can visually assess muscle involvement in children with SMA and has a good correlation with clinical indicators,which is a potential biomarker.
万方数据
维普
