Multiple system atrophy
Patient presented with progressive difficulty in walking, urinary incontinence, abnormal behavior, mild cognitive impairment and sleep disturbances for 3 years duration. On examination Mini mental score was 26/30. Cerebellar ataxia was present with rebound phenomenon. Hypertonia was observed in both upper and lower limbs with brisk tendon reflexes and extensor plantar reflex. There was no significant muscle wasting.
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Typical cruciform linear hyperintensity ("Hot Cross Bun" appearance) is seen in the pons specially on FLAIR and T2 weighted axial images. There is also atrophy of pons and middle cerebellar peduncles. The cerebellar hemispheres also appear atrophic and diffusely hyperintense on T2 wighted images. No restriction seen on Diffusion Weighted Images. Sagittal image show pontine and cerebellar atrophy. T2 coronal images demostrate mild hyperintensity of lateral margins of putamina.
Multiple system atrophy (MSA) is a adult onset, sporadic, progressive neurodegenerative disease of unknown aetiology, characterised clinically by parkinsonism, ataxia, cerebellar signs, and autonomic failure in any combination. In central nervous system imaging, hallmarks of multiple system atrophy occur due to selective loss of myelinated transverse pontocerebellar fibers and neurons in the pontine raphe with relative sparing of the cortico-spinal tracts and the pontine tegmentum. This appears on MRI as hot cross bun sign and is seen in the pons. This sign has also seen described with other neurodegenerative diseases such as spinocerebellar atrophy and parkinsonism. In a compatible clinical setting, detection of these changes on MRI is useful to confirm a diagnosis of MSA.
Contributed by Dr. Aruna Pallewatte, Dr. Madhavi Jayachandra
- 1. Naka H, Ohshita T, Murata Y et al. Characteristic MRI findings in multiple system atrophy: comparison of the three subtypes. Neuroradiology. 2002 Mar;44(3):204-9. .
- 2. Shrivastava A,The Hot Cross Bun Sign,Radiology 2007 245:2, 606-607