 Multiple system atrophy (MSA) is a rare disease characterized by Parkinson-like syndrome and degeneration of three systems (autonomic, cerebellar, and extrapyramidal). When atrophy affects the autonomic nervous system mainly, the disease is called Shy–Drager syndrome. MSA arises typically due to olivopontocerebellar atrophy and striatonigral degeneration. Postmortem findings in MSA reveal gliosis and/or neuronal loss in substantia nigra, putamen, caudate nuclei, cerebellar cortex, pontine nuclei, and inferior olive. Patients with MSA first show signs of Parkinson’s disease in their 40s, do not respond to antiparkinsonian medications, and usually succumb to the disease 7–10 years after symptom onset. Signs on MRI There is characteristic atrophy of three regions: putamen, pons, and cerebellum (the three systems). A characteristic pontine hyperintensity in a cross pattern referred to as hot cross bun sign may be seen, and it is a characteristic of this disease (Fig. 2.10.6). Abnormal decreased signal in the putamen on T1W and T2W images can be found. Fig. 2.10.6 Axial FLAIR brain MR illustrations demonstrate the characteristic “hot cross bun” sign of the multiple system atrophy (MSA) disorder (arrow). Notes: 1.autonomic /ˌɔːtə'nɒmɪk/ /ˌɔtə'nɑmɪk/ adj. 自主的; 不受意志支配的 2.olivopontocerebellar 橄榄桥小脑脚 3.striatonigral 纹状体 4.gliosis /glaɪ'osɪs/ /glaɪ'osɪs/ n. [医]神经胶质过多症 5.substantia nigra /səbˈstænʃiə/ /ˈnaɪɡrə/ n. 黑质 6.pontine nuclei 脚桥核 7.succumb /sə'kʌm/ /sə'kʌm/ vi. 不再抵抗(诱惑、疾病、攻击等);屈从 来源：每天朗读一段医学影像学英语文章 圈主 深圳市人民医院放射科副主任医师杨敏洁 |
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