Prediction of Neurological Impairment in Cervical Spondylotic Myelopathy using a Combination of Diffusion MRI and Proton MR Spectroscopy

Ellingson, Benjamin M.; Salamon, Noriko; Hardy, Anthony J.; Holly, Langston T.

doi:10.1371/journal.pone.0139451

Cited by 45 publications

(38 citation statements)

References 45 publications

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“…This is consistent with previous observations in patients with cervical spondylosis 6,10,12,14,22,23,28 . Additionally, we observed a significant correlation between degree of neurological impairment assessed using the mJOA and DTI measurements including FA and MD, which is also consistent with previous clinical studies 13,23 . Together, these results support the hypothesis that DTI measurements at the site of compression may be valuable for estimating the degree of neurological impairment in patients with cervical spondylosis.…”

Section: Discussionsupporting

confidence: 91%

Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy

Ellingson¹,

Salamon²,

Woodworth³

et al. 2018

Journal of Neurosurgery: Spine

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OBJECTIVEThe purpose of this study was to quantify the reproducibility, temporal stability, and functional correlation of diffusion MR characteristics in the spinal cord in patients with cervical stenosis with or without myelopathy. The association between longitudinal diffusion tensor imaging (DTI) measurements and serial neurological function assessment was explored at both the group and individual level.METHODSSixty-six nonoperatively treated patients with cervical stenosis were prospectively followed (3 months to > 5 years) using synchronous serial MRI and functional outcome assessment. A total of 183 separate MRI examinations were performed, separated by at least 3 months, and each patient had a minimum of 2 MRI scans (range 2–5 scans). Anatomical and DTI measurements were performed within the spinal cord at the C1–2 region as well as at the area of highest compression. Coefficients of variance (COVs) were compared across measurements in both reference tissue and areas of compression for anatomical measurements, fractional anisotropy (FA), and mean diffusivity (MD). The correlation between diffusion MR measures at the site of compression and evaluations of neurological function assessed using the modified Japanese Orthopaedic Association (mJOA) scale at multiple time points was evaluated.RESULTSThe COVs for anatomical measurements (Torg ratio and canal diameter) were between 7% and 10%. The median COV for FA measurements at the site of compression was 9%, and for reference tissue at C1–2 it was 6%. The median COV for MD at the site of compression was approximately 12%, and for reference tissue at C1–2 it was 10%. The FA and MD measurements of C1–2 averaged 0.61 and 0.91 μm2/msec, respectively, whereas the FA and MD measurements at the site of compression averaged 0.51 and 1.26 μm2/msec, respectively. Both FA (slope = 0.037; R2 = 0.3281, p < 0.0001) and MD (slope = −0.074; R2 = 0.1101, p = 0.0084) were significantly correlated with the mJOA score. The FA decreased by approximately 0.032 units per mJOA unit decrease (R2 = 0.2037, p < 0.0001), whereas the MD was increased by approximately 0.084 μm2/msec for every mJOA unit decrease (R2 = 0.1016, p < 0.0001).CONCLUSIONSQuantitative DTI measurements of the spinal cord in patients with cervical stenosis with or without myelopathy have a median COV of 5%–10%, similar to anatomical measurements. The reproducibility of these measurements and significant correlation with functional outcome status suggest a potential role in the evaluation and longitudinal surveillance of nonoperatively treated patients. With respect to the specific DTI measurements, FA within the spinal cord appears slightly more sensitive to neurological function and more stable than measures of MD. Therefore, DTI of the spinal cord may be a clinically feasible imaging technique for longitudinally monitoring patients with cervical spondylotic myelopathy.

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Section: Discussionsupporting

confidence: 91%

Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy

Ellingson¹,

Salamon²,

Woodworth³

et al. 2018

Journal of Neurosurgery: Spine

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“…It is unclear whether these metabolic changes are permanent (suggesting neuronal or axonal loss) or whether reduced NAA indicates mitochondrial dysfunction that is potentially reversible. 7 Of note, similar findings using 1 H-MRS of the cervical spinal cord have been reported by Salamon et al 17 and Ellingson et al, 9 suggesting decreases in NAA account for axonal loss and decreased metabolic function. When comparing decreases in the absolute concentration of NAA between the motor and sensory cortices, a temporal difference was observed.…”

Section: Discussionsupporting

confidence: 69%

N-acetylaspartate in the motor and sensory cortices following functional recovery after surgery for cervical spondylotic myelopathy

Goncalves¹,

Stevens²,

Doyle-Pettypiece

et al. 2016

SPI

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OBJECTIVE Cervical spondylotic myelopathy (CSM) is the most common cause of reversible spinal cord dysfunction in people over the age of 55 years. Following surgery for symptomatic CSM, patients demonstrate motor improvement early in the postoperative course, whereas sensory improvement can lag behind. The authors of the present study hypothesized that changes in the concentration of N-acetylaspartate (NAA) in the motor and sensory cortices in the brain would emulate the time course of neurological recovery following decompression surgery for CSM. Their aim was to compare and contrast how metabolite levels in the motor and sensory cortices change after surgery to reverse downstream spinal cord compression. METHODS Twenty-four patients with CSM and 8 control subjects were studied using proton MR spectroscopy (1H-MRS) images acquired on a 3.0-T Siemens MRI unit. The 1H-MRS data (TE 135 msec, TR 2000 msec) were acquired to measure absolute levels of NAA from the motor and sensory cortices in the cerebral hemisphere contralateral to the side of greater deficit at baseline in each subject. Data were also acquired at 6 weeks and 6 months following surgery. Control subjects were also evaluated at 6 weeks and 6 months following baseline data acquisition. Neurological function was measured in each subject at all time points using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) questionnaire, and the American Spinal Injury Association (ASIA) neurological classification. RESULTS In the motor cortex of patients, NAA levels decreased significantly (p < 0.05) at 6 weeks and 6 months postsurgery compared with baseline levels. In the sensory cortex of patients, NAA levels decreased significantly (p < 0.05) only at 6 months after surgery compared with baseline and 6-week levels. No significant changes in NAA were found in control subjects. Clinical scores demonstrated significant (p < 0.05) motor recovery by 6 weeks, whereas sensory improvements (p < 0.05) appeared at only 6 months. CONCLUSIONS Findings suggest that metabolite changes in both the motor and sensory cortices mimic the time course of functional motor and sensory recovery in patients with CSM. The temporal course of neurological recovery may be influenced by metabolic changes in respective cortical regions.

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“…However, DWI is challenging in the spine because of its limited size, motion and field inhomogeneities. These limit performance for traditional DTI methods in clinical CSM assessment . Using our newly developed technique, high‐resolution DTI can provide DWI images with fewer artifacts and more accurate measurements with an acceptable reproducibility, especially in cases with metal implants (Figures and ), in comparison with ss‐EPI DWI.…”

Section: Discussionmentioning

confidence: 99%

“…This technique has also been applied in various spinal cord diseases: acute spinal cord compression, inflammatory diseases, arteriovenous malformation, ischemia and others . In particular, DTI has been attempted in patients with CSM, and the results have shown that increased apparent diffusion coefficient (ADC) can be detected at stenotic segments . In addition, ADC values have been investigated for their ability to predict clinical recovery after decompression surgery .…”

Section: Introductionmentioning

confidence: 99%

High‐resolution diffusion tensor imaging in cervical spondylotic myelopathy: a preliminary follow‐up study

et al. 2017

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Diffusion imaging is a promising technique as it can provide microstructural tissue information and thus potentially show viable changes in spinal cord. However, the traditional single-shot imaging method is limited as a result of various image artifacts. In order to improve measurement accuracy, we used a newly developed, multi-shot, high-resolution, diffusion tensor imaging (DTI) method to investigate diffusion metric changes and compare them with T -weighted (T2W) images before and after decompressive surgery for cervical spondylotic myelopathy (CSM). T2W imaging, single-shot DTI and multi-shot DTI were employed to scan seven patients with CSM before and 3 months after decompressive surgery. High signal intensities were scored using the T2 W images. DTI metrics, including fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD), were quantified and compared pre- and post-surgery. In addition, the relationship between imaging metrics and neurological assessments was examined. The reproducibility of multi-shot DTI was also assessed in 10 healthy volunteers. Post-surgery, the mean grade of cervical canal stenosis was reduced from grade 3 to normal after 3 months. Compared with single-shot DTI, multi-shot DTI provided better images with lower artifact levels, especially following surgery, as a result of reduced artifacts from metal implants. The new method also showed acceptable reproducibility. Both FA and RD values from the new acquisition showed significant differences post-surgery (FA, p = 0.026; RD, p = 0.048). These changes were consistent with neurological assessments. In contrast, T2W images did not show significant changes before and after surgery. Multi-shot diffusion imaging showed improved image quality over single-shot DWI, and presented superior performance in diagnosis and recovery monitoring for patients with CSM compared with T2W imaging. DTI metrics can reflect the pathological conditions of spondylotic spinal cord quantitatively and may serve as a sensitive biomarker for potential CSM management.

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Prediction of Neurological Impairment in Cervical Spondylotic Myelopathy using a Combination of Diffusion MRI and Proton MR Spectroscopy

Cited by 45 publications

References 45 publications

Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy

Reproducibility, temporal stability, and functional correlation of diffusion MR measurements within the spinal cord in patients with asymptomatic cervical stenosis or cervical myelopathy

N-acetylaspartate in the motor and sensory cortices following functional recovery after surgery for cervical spondylotic myelopathy

High‐resolution diffusion tensor imaging in cervical spondylotic myelopathy: a preliminary follow‐up study

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