Spinal cord atrophy correlates with disability in Friedreich's ataxia.

Although Friedreich's ataxia is characterized by spinal cord atrophy, it remains to be investigated the possible correlation of such atrophy with clinical disability and genetic parameters. Thirty-three patients with Friedreich's ataxia and 30 healthy controls underwent MRI on a 3 T scanner. We used T1-weighted 3D images to estimate spinal cord area and eccentricity at C2/C3 level based on a semi-automatic image segmentation protocol. We quantified severity of ataxia with the Friedreich ataxia rating scale (FARS). Mean cord area in Friedreich's ataxia was smaller than in controls (38 vs 67.9 mm(2), p < 0.001). In contrast, mean cord eccentricity was significantly higher in Friedreich's ataxia when compared to the controls (0.82 vs 0.76, p < 0.001). There was a significant correlation between cord areas and the FARS scores (r = -0.53, p = 0.002). Cord damage in Friedreich's ataxia results in atrophy combined with flattening. Cord area is associated to clinical disability and might be useful as a biomarker in the disease.