Classification of cerebellar atrophy using voxel-based morphometry and SPECT with an easy Z-score imaging system

With conventional MRI and single-photon emission computed tomography (SPECT), accurate diagnosis and precise classification of cerebellar atrophy are often difficult. The objective was to verify the utility of MRI voxel-based morphometry (VBM) in combination with SPECT using easy Z-score imaging (eZIS) for diagnosing and classifying cerebellar atrophy.

We assessed gray matter atrophy using VBM and blood perfusion using SPECT with eZIS in fifteen patients with different types of cerebellar atrophy, such as the cerebellar variant of multiple system atrophy (MSA-C), spinocerebellar ataxia type 3 (SCA3), SCA6, and autoimmune cerebellar ataxia (AICA).

In all five MSA-C patients, VBM imaging showed atrophy of the brainstem, the entire cerebellar vermis, and the cerebellar hemispheres, while SPECT using eZIS showed reduced perfusion in the same regions. Regarding SCA3, brainstem atrophy and reduced perfusion were recognized in two of the four patients, but none exhibited abnormal findings in the posterior lobe of the cerebellar vermis. SPECT showed that all four patients had obviously reduced perfusion in the anterior lobe of the vermis, but VBM demonstrated that there was no obvious atrophy of gray matter in any patient, meaning that the results of SPECT and VBM contradicted each other completely. All SCA6 and AICA patients exhibited atrophy and reduced perfusion in the cerebellar hemispheres but not in the brainstem. Only one AICA patient exhibited atrophy and reduced perfusion of the entire cerebellar vermis.

VBM clearly showed characteristic gray matter atrophy in the cerebellum and brainstem in different pathological conditions, thus indicating its high degree of utility in diagnosing and classifying cerebellar atrophy in combination with SPECT using eZIS.