Diffusion tensor imaging in cervical syringomyelia secondary to Chiari I malformation: preliminary results.

Abstract

A prospective observational analysis. The aim was to perform a quantitative analysis of the neuronal status in cervical syringomyelia secondary to Chiari I malformation (CMI-S) using diffusion tensor imaging. Syringomyelia is a common finding in patients with CMI. Conventional imaging techniques frequently fail to assist clinicians in quantitatively assessing the neural damage in these patients. Twenty-three patients with CMI-S (aged 8-25 yr) were prospectively enrolled from April 2012 to August 2013. Sensitivity encoding single-shot echo-planar imaging was used for the sagittal diffusion tensor imaging. Fractional anisotropy (FA) values in the spinal cord were compared between the patients and normal volunteers and further evaluated with respect to syrinx severity and neurological signs/symptoms. Compared with the normal controls, the FA values were significantly decreased at the level of the syrinx (0.429 ± 0.015 vs. 0.533 ± 0.007; P < 0.001), whereas no significant decreased FA value was measured in the tissue rostral and caudal to the syrinx. Concerning patients with different size of the syrinx, significantly decreased FA values at the syrinx level were observed in patients with a distended syrinx in comparison with those with a nondistended syrinx (0.397 ± 0.013 vs. 0.480 ± 0.018; P < 0.001). Moreover, the FA value at the syrinx level was found to be significantly decreased in the symptomatic group when compared with the nonsymptomatic or control groups (P < 0.05), and there was also a significant difference between the 2 latter groups (P < 0.05). Decreased FA value at the syrinx levels may provide evidence of increased microstructural damage within the spinal cord parenchyma at this area, and changes in this diffusion tensor imaging parameter are significantly related to syrinx size and to the appearance of neurological signs/symptoms. 4.