136 Diffusion Tensor Imaging for the Assessment of Cord Compression in Degenerative Cervical Stenosis.

This study aims to test the value of diffusion tensor (DT) magnetic resonance (MR) imaging and fractional anisotropy (FA) mapping in detection of early cord dysfunction due to cervical spondilotic myelopathy before myelopathy is apparent on T2 weighted MR images Methods Totally 21 patients with neurological signs and symptoms of degenerative cervical stenosis enrolled in the study. None of the participants had hyperintense signal changes on T2 weighted MR images suggestive of myelopathy. The spinal cord dysfunction is defined by delayed somatosensory evoked potential (SEP) responses. The magnetic resonance (MR) examinations were performed on a 1,5-T MR imaging system. Apparent diffusion coefficient (ADC) and axial fractional anisotropy (FA) maps were generated. The ADC and FA measurements in each individual were made at the level of most severe cervical canal stenosis and at nonstenotic levels. Student’s t test was used to compare FA and ADC values of the spinal cord in stenotic and nonstenotic segments. Results All patients showed statistically significant decrease in FA values and statistically significant increase in ADC values in stenotic segments (p<0.001). In addition, distortions of spinal cord diffusion in stenotic segments were visualized on sagittally reformatted colored FA maps. The impairment in SEP responses correlated with decreases in diffusion values. CHANGES IN ADC AND FA VALUES IN NON STENOTIC, STENOTIC AND MYELOMALASIC SEGMENTS