Background: Brainstem and cerebellar atrophy are the most important features in magnetic resonance imaging (MRI) in spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD). However, the correlation between brainstem and cerebellar atrophy and the clinical features has not been well studied.

Aim: To study the correlation between MRI features of the brainstem and cerebellum and predominant clinical features in SCA3/MJD.

Design and setting: University teaching hospital.

Patients and methods: By using the linear measurement method, we assessed 32 patients with SCA3/MJD to study the correlations between the morphometric data of the brainstem and cerebellum and clinical features: Duration of the disease, age of onset, total international cooperative ataxia rating scale (ICARS) score; total scale for the assessment and rating of ataxia (SARA) score; ICARS subscores, and SARA subscores.

Statistical analysis: Pearson correlation test.

Results: There was a significant inverse correlation between anteroposterior diameter of the midbrain and pons and total ICARS scores, total SARA scores, ICARS and SARA subscores (r = -0.381 approximately -0.57, P < 0.05 or 0.01) and disease duration (r = -0.42 approximately -0.51, P < 0.05 or 0.01). Additionally, superoinferior diameter of the cerebellum was inversely correlated with total SARA scores and ICARS and SARA subscores except for ataxia of posture and gait in both scales (r = - 0.37 approximately -0.44, P < 0.05). The superoinferior diameter of the fourth ventricle was inversely correlated with age of onset (r = -0.45, P < 0.05).

Conclusion: The effect on the cerebellum and brainstem is related to predominant clinical features in SCA3/MJD patients.