Clinical Correlates of High Cervical Fractional Anisotropy in Acute Cervical Spinal Cord Injury

Abstract

Objective: Fractional anisotropy (FA) of the high cervical cord (C1-C2), rostral to the injury site, correlates with upper limb function in patients with chronic cervical spinal cord injury (SCI). In acute cervical SCI, this relationship has not been investigated. The objective of this study was to identify functional correlates of FA of the high cervical cord in a series of patients with acute cervical SCI. Methods: Traumatic cervical SCI patients who underwent presurgical cervical spine diffusion tensor imaging at our institution were reviewed for this study. FA of the whole cord as well as the lateral corticospinal tracts (CSTs) was calculated on axial images from C1-C2. Upper limb motor (C5-T1) and sensory (C2-T1) function scores were extracted from the admission American Spinal Injury Association (ASIA) examinations. Correlation analysis for FA with ASIA examinations was performed using a Pearson correlation. Results: Twelve subjects (9 men, 3 women; mean age 54.7 ± 4.0 years) underwent cervical spine diffusion tensor imaging at a mean duration of 3.6 ± 0.9 days postinjury. No patient had cord compression or intramedullary T2-weighted hyperintensities within the C1-C2 segments. FA correlated with upper limb motor score (whole cord: r = 0.59, P = .04; CST: 0.67, P = .01) and the ASIA grade (whole cord: r = 0.61, P = .03; CST: r = 0.71, P = .009). No correlation was found between FA and sensory scores. Conclusions: FA of the whole cervical cord as well as the CST, rostral to the injury site, is associated with preserved upper limb motor function as well as superior ASIA grades after acute cervical SCI. FA of the high cervical cord is a potential biomarker of neural injury after acute cervical SCI.

Use of Spinal Cord Diffusion Tensor Imaging to Quantify Neural Ablation and Evaluate Outcome after Percutaneous Cordotomy for Intractable Cancer Pain

“…Animal studies of experimental spinal cord injury have shown an early decrease in FA after the injury [15]. Human studies in acute spinal cord injury have also described a significant decrease in FA in early spinal cord DTI after the injury [8, 16]. In the present study, changes in FA were sensitive to the number of ablations performed during the procedure.…”

“…DTI is able to characterize microstructural changes within neural tissues, such as the spinal cord, and has been used to assess spinal cord lesions after spinal cord injury [7, 8] as well as microstructural changes in patients with cervical spondylotic myelopathy [9, 10]. To date, the role of DTI in characterizing the lesion produced by cordotomy has not been explored.…”

A Novel MRI Biomarker of Spinal Cord White Matter Injury: T2*-Weighted White Matter to Gray Matter Signal Intensity Ratio

“…This region is also potentially useful for the prediction of outcomes in acute SCI, with a postoperative scan in the days to weeks following early surgical decompression. 38 The caudal region consistently showed the weakest results, likely due to respiratory motion, susceptibility artifacts from the lungs, and increased partial volume effects due to the angle between sections and the SC (in subjects with irreducible cervical lordosis). Despite these issues, T2*WI WM/GM and FA showed some utility in this region.…”

“…7 It was encouraging to also find strong results rostrally for T2*WI WM/GM, which has been previously reported for FA. 14,38 This finding has important clinical implications because this region avoids the aforementioned issues and can be used for postoperative assessment rostral to metallic implants in most patients with DCM. This region is also potentially useful for the prediction of outcomes in acute SCI, with a postoperative scan in the days to weeks following early surgical decompression.…”

Diffusion MRI of the spinal cord: from structural studies to pathology

“…Therefore it is not surprising that, in recent years, much effort has focused on imaging of traumatic SCI . Diffusion MRI in general and DTI in particular have been extensively used to study traumatic SCI both ex vivo and in vivo in experimental models and also in human subjects . Early work focused more on ex vivo diffusion MRI studies of traumatic SCI, but more recently in vivo studies have been conducted.…”