Diffusion tensor imaging in injuries of the cervical spine in children

Abstract

Introduction. The technique of diffusion tensor imaging (DTI) is widely used in brain examination. However, DTI application for examining the spinal cord, especially in children, is not easy: small dimensions of the spinal cord with a typical low signal-to-noise ratio, artifacts from the respiration and pulsation of the heart and large vessels, as well as from swallowing movements. EPI sequences used to obtain diffusion indices cause eddy current distortions.Objective. To study changes in  DTI parameters of the spinal cord in children with cervical spinal cord injury.Material and methods. 56 children aged 2–17 years with cervical spine injury (CSI) and 20 children without CSI were examined with  Phillips Achieva3 T magnetic resonance scanner. The protocol consisted of sagittal STIR, sagittal and axial T1- and T2WI SE and axial DTI. To assess DTI, the following parameters were calculated: apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial (AD) and radial (RD) diffusion coefficients.Results. By ASIA criteria, 29 (51%) children out of 56 had CSI with neurological complications; 27 (49%) had no complications. Neurological dysfunction of degree A was in 13 patients; B – in 3; C – in 9; D – in 4; E – in 27. Average values of  diffusion in patients were: ADC = 0.74 ± 0.12 • 10−3 mm2/s−1, FA = 0.36 ± 0.07, BP = 1.15 + 0.28 • 10−3 mm2/s−1, RD = 0.52 + 0.32 • 10−3 mm2/s−1.Conclusion. DTI can detect changes which cannot be detected by conventional MRI. Low ADC values in the acute injury may indicate spinal cord injury and predict a negative functional outcome.