FRIEDREICHS ATAXIA - MR FINDINGS INVOLVING THE CERVICAL PORTION OF THE SPINAL-CORD

OBJECTIVE. Loss of myelinated fibers and gliosis in the posterior and lateral columns of the spinal cord are histopathologic hallmarks of Fr iedreich's ataxia. These are accompanied by atrophy of the upper porti on of the spinal cord. We performed a study to determine if MR imaging can be used to detect signal changes in the white matter tracts of th e cervical spinal cord in these patients. SUBJECTS AND METHODS. The ce rvical spinal cord was imaged with a 0.5-T MR imaging system in 10 pat ients with Friedreich's ataxia and in 14 patients with cerebellar atax ias, who served as control subjects. In all of them, the examination p rotocol included sagittal T1-weighted spin-echo images, sagittal short TI inversion-recovery images, and axial cardiac-gated long TR spin-ec ho or ungated low-flip-angle (20 degrees) gradient-recalled-echo image s from C2 to C6. The anteroposterior diameter of the spinal cord at th e level of C3 on axial images was measured on the display console in p atients and control subjects. Two observers who did not know the clini cal diagnosis were then asked to evaluate hard copies of the entire im age set for each subject for possible intramedullary signal abnormalit ies. RESULTS. The anteroposterior diameter of the spinal cord was decr eased in all but one of the patients with Friedreich's ataxia. Abnorma l signal in the posterior or lateral columns of the spinal cord was ob served on sagittal and axial images in nine patients with Friedreich's ataxia and in none of the control subjects. CONCLUSION. MR images of the cervical spinal cord in patients with Friedreich's ataxia show thi nning and intramedullary signal changes in the cervical portion of the spinal cord, consistent with degeneration of posterior and lateral wh ite matter tracts. These MR findings might be helpful for differential diagnosis in patients with progressive ataxia of uncertain clinical t ype.