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The Assessment of Neuronal Status in Normal and Cervical Spondylotic Myelopathy Using Diffusion Tensor Imaging

Rajasekaran, S. PhD*; Yerramshetty, Janardhan S. PhD; Chittode, Vishnuprasath S. FNB; Kanna, Rishi M. FNB*; Balamurali, Gopalakrishnan MD*; Shetty, Ajoy Prasad MS*

doi: 10.1097/BRS.0000000000000369
Cervical Spine

Study Design. A prospective observational analysis of diffusion tensor imaging (DTI) datametrics collected from control and patients with cervical spondylotic myelopathy (CSM).

Objective. The aims were to study the use of DTI in CSM and to probe whether DTI datametrics and tractography will correlate with magnetic resonance imaging and clinical findings.

Summary of Background Data. Magnetic resonance imaging is the current “gold standard” in the assessment of cord status in CSM; however, various parameters such as extent of compression and presence of signal intensity changes do not correlate well with clinical status. DTI is a novel investigation tool with proven applications in brain pathologies but is not routinely used in spinal cord evaluation.

Methods. Patients with CSM (n = 35) who required surgical decompression (mean age = 48 yr) and 40 normal individuals (mean age = 38 yr) were included. Diffusion Tensor Imaging of the cervical spine was obtained using a 1.5T magnetic resonance image. Apparent diffusion coefficient, fractional anisotropy, and eigenvalues (E1, E2, and E3) were obtained at each cervical level. The DTI datametrics of CSM patients were compared with normal volunteers and correlated with individual and grouped Nurick grades, which indicate the neurological status of patients.

Results. There was significant difference in DTI datametrics between patients with myelopathy and control (P < 0.05), with decrease in fractional anisotropy (0.49 ± 0.081 vs. 0.53 ± 0.07) and increase in apparent diffusion coefficient (1.8 ± 0.315 vs. 1.44 ± 0.145) and eigenvalues (E1: 2.82 ± 0.395 vs. 2.37 ± 0.221, E2: 1.64 ± 0.39 vs. 1.18 ± 0.198, E3: 0.956 ± 0.277 vs. 0.76 ± 0.142). There was also a significant difference between increasing grades of myelopathy when individuals were grouped as—control, self-ambulant (Nurick grades 1 and 2), and dependent (Nurick grades 3, 4, and 5).

Conclusion. The study shows that DTI is a promising and useful investigational tool in evaluation of CSM. There was a significant difference in all DTI values between control and patients with CSM, and there was a significant trend of change in values between control, self-ambulant, and dependent patients. Our results encourage further investigation of this important modality.

Level of Evidence: 3

Magnetic resonance imaging, used for diagnosis and prognosis of spine-related problems, cannot quantify severity, especially in patients with cervical spondylotic myelopathy. Our study documented that correlation between diffusion tensor imaging datametrics and neurological status and tractography was able to identify the main level that was causing the symptoms, in case of multilevel compression.

*Ganga Hospital, Coimbatore, Tamil Nadu, India; and

Ganga Orthopaedic Research and Education Foundation, Tatabad, Coimbatore, Tamil Nadu, India.

Address correspondence and reprint requests to S. Rajasekaran, PhD, Ganga Hospital, 313 Mettupalayam Rd, Coimbatore, Tamil Nadu, India 641043; E-mail: sr@gangahospital.com

Acknowledgment date: December 25, 2013. Revision date: February 24, 2014. Acceptance date: March 27, 2014.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Ganga Orthopaedic Research and Education Foundation, Coimbatore, India; Department of Biotechnology, New Delhi, India; and AOSpine Foundation (Asia Pacific), Kowloon, Hong Kong, funds were received to support this work.

Relevant financial activities outside the submitted work: grants/grants pending.

© 2014 by Lippincott Williams & Wilkins