An In vivo study using MRI-based Volumetry and fractional anisotropy in genetically proven SCA1 of 10 patients within a single subdistrict in Thailand

Abstract

Purposes: To determine the volume of the posterior fossa structures and pattern of fractional anisotropy values in SCA1 patients compared to normal subjects as well as investigate any correlation between degree of ataxia and posterior fossa volume. Materials and methods: After institutional review board approval, a cross sectional analytical study of the patients who were genetically proven SCA1 compared to age- and sex-matched control groups was performed. The patients underwent neurologic examination and ataxic symptoms were accessed using the scale for the assessment and rating of ataxia (SARA). The control group was also neurologically examined to pronounce normal neurological status. The patients and control subjects underwent MRI examination using 1.5 T system in at least following sequences; Sagittal 3DFSPGR, AxialT1WI, PD/T2WI, DWI, FLAIR and DTI. Finally, the data showing the volume of posterior fossa structures and FA values were collected using SPSS 17.0 software to find any statistically significant difference in the volume between the two groups and to assess any correlation of the degree of ataxia and structural volume loss. Results: There are statistically significant differences between the volume of all regions including cerebellar vermis, cerebellar hemispheres and brainstem in SCA1 patients and control subjects. There are also significant negative correlations between the ataxic score (SARA scale) and the volumes of cerebellar vermis and brainstem in SCA1 patients. There are statistically significant differences in the FA values in the regions of corticospinal tract at pons, transverse pontine fiber, superior cerebellar peduncle, middle cerebellar peduncle and cerebellar white matters between SCA1 patients and normal controls. The only exception is the corticospinal tract at cerebral peduncle where the difference is not statistically significant. Conclusion: The MRI-based volumetry correlates well with the severity of the disease and, without doubt, establishes a significant difference between patients and age and sex-matched controls. Additionally, the fractional anisotropy shows findings correspond to the neuropathology of the disease.