Assessing Spinal Cord Injury Area in Patients with Tethered Cord Syndrome by Diffusion Tensor Imaging

OBJECTIVE: We evaluated the spinal cord injury range in patients with tethered cord syndrome (TCS) who had urinary incontinence. METHODS: We included 30 subjects in the present study, 15 with tethered cord syndrome and urinary incontinence and 15 normal volunteers. All 30 subjects underwent magnetic resonance diffusion tensor imaging (DTI). Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated from a region of interest). All the patients and volunteers were measured 4 segments above the conus medullaris. RESULTS: All the FA values and ADC values could be measured from the DTI scans in the normal volunteers and patients. The average ADC value was 1.244 +/- 0.061 in the control group and 1.052 +/- 0.045 in the TCS group. The difference was statistically significant (P < 0.05). The average FA value was 0.866 +/- 0.030 in the control group and 1.079 +/- 0.049 in the TCS group, with a statistically significant difference (P < 0.05). The differences in the ADC values in each segment were statistically significant in the 2 groups, although only the difference in the FA value of the fourth segment above the conus medullaris was statistically significant in the 2 groups. CONCLUSION: DTI can detect the spinal cord damage range in patients with TCS. In the patients with urinary incontinence, the spinal cord damage was widespread, and the most severe lesion was at the fourth segment above the conus medullaris. This might indicate that decompression of the spinal cord should at least include the fourth segment above the conus medullaris.