Longitudinal quantitative MRI in multiple system atrophy and progressive supranuclear palsy.

OBJECTIVE

MRI has been used in parkinsonism to assess atrophy, tissue water diffusivity, and mineral deposition but usually at a single time-point. However, multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) are progressive diseases. This study assessed the value of longitudinal MRI in characterizing the time course of the degenerative process.

METHODS

Two serial MRIs (mean 23 months apart) were retrospectively analyzed in 12 MSA, 6 PSP, and 18 age and sex matched controls. Assessment included selected cross-sectional areas, regional apparent diffusion coefficient (ADC) and gradient echo (GRE) intensity ratios of the lateral ventricles, caudate, putamen, middle cerebellar peduncle, pons and midbrain.

RESULTS

On follow-up imaging, there was a larger ADC increase in the putamen in PSP over time compared to controls (p = 0.02). In MSA there was greater volume loss in the pons over time compared to controls (p = 0.002). In MSA the changes in middle cerebellar peduncle ADC were correlated with motor symptom severity according to the Unified Parkinson's Disease Rating Scale Part III (p = 0.005).

CONCLUSIONS

Evidence of progressive neurodegeneration can be observed on MRI in MSA and PSP within two years consisting of increasing putaminal ADC in PSP and pontine atrophy in MSA.