Efficacy of diffusion tensor imaging in identification of degenerative cervical spondylotic myelopathy

Utility of Diffusion Tensor Imaging in Predicting Outcomes Following Surgical Treatment of Degenerative Cervical Myelopathy

BACKGROUND

The utility of diffusion tensor imaging (DTI) in predicting surgical outcomes in degenerative cervical myelopathy (DTI) remains controversial.

OBJECTIVE

To identify the preoperative clinical and radiological factors associated with poor outcomes following surgical treatment of DCM.

METHODS AND MATERIAL

This prospective cohort study included patients who underwent surgery for DCM. MRI parameters (compression ratio, CR; transverse area, TA; signal-intensity ratio, SIR) and DTI parameters (fractional anisotropy, FA; apparent diffusion coefficient, ADC; relative anisotropy, RA; volume ratio, VR) were assessed preoperatively. Demographic and operative data were collected. Based on the improvement in modified Japanese Orthopaedic Association (mJOA) score at 4 months, patients were categorized as group A (good surgical outcome) and group B (poor surgical outcome). Univariate and regression analyses were performed to identify risk factors and predictors, respectively, of poor surgical outcome.

RESULTS

Sixty-six patients were included. Thirty-eight patients belonged to group A (good outcome) and 28 patients belonged to group B (poor outcome). There was no significant difference between the two groups in demographic and operative variables. FA was found to be significantly less in group B compared to group A (550 vs. 610, P = 0.04). No significant difference was seen in RA, CR, TA, SIR, ADC, and VR between the two groups. On regression analysis, no independent predictor of poor outcome could be identified.

CONCLUSIONS

Preoperative FA was found to be significantly lower in patients with poor outcome following surgical treatment for DCM.

The apparent diffusion coefficient based on small-field DWI is superior to T2-weighted imaging in evaluating neurological dysfunction of degenerative cervical myelopathy

PURPOSE

To investigate the clinical application of zonally magnified oblique multislice (ZOOM) imaging technology in patients with degenerative cervical myelopathy (DCM) and compare it with T2WI imaging.

METHODS

A total of 111 patients diagnosed with DCM were recruited. According to mJOA, patients with DCM were divided into ND + group with neurological dysfunction and ND- group without neurological dysfunction. Routine MRI and ZOOM-DWI were performed on 3.0 T MRI to obtain sagittal T2WI and apparent diffusion coefficient (ADC) diagram. ADC values of the narrow segment and its adjacent upper and lower segments were measured, and compared between the ND + and ND- groups. The correlation between ADC value of cervical spinal cord and mJOA score was analyzed. Additionally, ROC curves were plotted to calculate the AUC values.

RESULTS

The comparison between ND + and ND- groups shows that there are significant differences in mJOA score, T2WI, anteroposterior diameter of spinal canal, ADC values of narrow, upper and lower segment (P < 0.05). In ND + group, there is a significant difference between ADC values of the narrow and its upper and lower segments (P < 0.001), while with no significant difference in ADC values of the upper and lower segments (P > 0.05). Results of correlation analysis indicate that in the ND + group, neurological dysfunction evaluated by mJOA scores is correlated with increased ADC values of the narrow segment (r = -0.52, P < 0.001), but not significantly correlated with ADC values of the upper and lower segments. Furthermore, T2WI, anteroposterior diameter of the spinal canal, and cervical cord ADC values all has diagnostic efficacy in evaluating neurological dysfunction in DCM (AUC > 0.5, P < 0.05), with the ADC value of the narrow segment being optimal.

CONCLUSION

The ADC value of spinal cord obtained by small-field ZOOM-DWI can be used to evaluate neurological dysfunction in DCM, and is superior to traditional T2WI.

The use of diffusion tensor imaging in spinal pathology: a comprehensive literature review

STUDY DESIGN

We reviewed the available literature systematically without meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

OBJECTIVE

To evaluate contemporary literature on use of spinal diffusion tensor imaging(sDTI) in spinal pathology.

BACKGROUND

sDTI reveals the location and functional state of critical long tracts and is a potentially useful adjunct in disease management.

METHODS

Studies were included if they presented or discussed data from investigative or therapeutic procedures involving sDTI on human subjects in the setting of surgically amenable spinal pathology. Studies were excluded if they were (1) restricted to computational models investigating parameters using data not obtained clinically, (2) about cranial DTI methods, (3) about spinal pathology data not related to surgical management, (4) discussions or overviews of methods/techniques with minimal inclusion of objective experimental or clinical data.

RESULTS

Degenerative pathologies of interest were restricted to either cervical myelopathy (22/29,75.9%) or lumbar spondylosis 7/29,24.1%). Mass-occupying lesions included intradural pathology and discussed preoperative (7/9,77.8%) and intraoperative imaging(2/9,22.2%) as an adjunct to surgery 22.2%. Traumatic pathology focused on spinal cord injury prognosis and severity grading.

CONCLUSIONS

sDTI seems useful in surgical decision making and outcome measurements and in establishing clinical prognoses over a wide range of surgical pathologies. Further research is warranted with longer follow-up and larger population sizes in a prospective and controlled protocol.

Diagnostic value of cervical spine ZOOM-DWI in cervical spondylotic myelopathy

PURPOSE

To investigate the clinical application value of the non-shared incentive diffusion imaging technique (ZOOM-DWI) diagnoses of cervical spondylotic myelopathy (CSM).

METHODS

49 CSM patients who presented from January 2022 to December 2022 were selected as the patient group, and 50 healthy volunteers are recruited as the control group. All subjects underwent conventional MRI and ZOOM-DWI of the cervical spine and neurologic mJOA scores in patients with CSM. The spinal ADC values of segments C2-3, C4-5, C5-6, and C6-7 are measured and analyzed in all subjects, with C5-6 being the most severe level of spinal canal compression in the patient group. In addition, the study also analyzes and compares the relationship between the C5-6 ADC value and mJOA score in the patient group.

RESULTS

The mean ADC shows no significantly different levels in the control group. Among the ADC values at each measurement level in the patient group, except for C4-5 and C6-7 segments are not statistically significant, the remaining pair-wise comparisons all show statistically significant differences (F = 24.368, p < 0.001). And these individuals have the highest ADC value at C5-6. The C5-6 ADC value in the patient group is significantly higher compared with the ADC value in the control group (t = 9.414, p < 0.001), with statistical significance. The ADC value at the patient stenosis shows a significant negative correlation with the mJOA score (r = -0.493, p < 0.001).

CONCLUSION

Cervical ZOOM-DWI can be applied to diagnose CSM, and spinal ADC value can use as reliable imaging data for diagnosing cervical myelopathy.

The usefulness of the apparent diffusion coefficient value in diagnosing acute spinal cord ischemia

The purpose of our study was to assess the usefulness of the apparent diffusion coefficient (ADC) value in differentiating between a normal spinal cord and a spinal cord with acute ischemia. Control group of 113 and 8 acute spinal cord ischemia patients were enrolled in this study. The ADC values were measured when diffusion-weighted imaging was first performed after the onset of acute spinal cord ischemia. The mean ADC value each of the control group and acute spinal cord ischemia patients was 0.99 ± 0.19 × 10-3 mm2/s and 0.70 ± 0.15 × 10-3 mm2/s. The mean ADC value in patients with acute spinal cord ischemia was significantly lower than that in patients with a normal spinal cord (P < 0.01). We found the cutoff ADC value (0.86 × 10-3 mm2/s) to be a useful indicator of acute spinal cord ischemia (sensitivity = 100.0%, specificity = 71.7%, AUC = 0.92). In conclusions, it is suggested that the ADC value may be useful in the diagnosis of acute spinal cord ischemia.

Role of diffusion kurtosis imaging in evaluating microstructural changes in spinal cord of patients with cervical spondylosis

STUDY DESIGN

Analytical cross-sectional study.

PURPOSE

To study the role of diffusion kurtosis imaging (DKI) in evaluating microstructural changes in patients with cervical spondylosis.

OVERVIEW OF LITERATURE

Cervical spondylosis is a common progressive degenerative disorder of the spine. Conventional magnetic resonance imaging (MRI) can only detect the changes in the spinal cord once there are visual signal changes; hence, it underestimates the extent of the injury. Newer imaging techniques like Diffusion Tensor and Kurtosis Imaging can evaluate the microstructural changes in cervical spinal cord before the obvious signal changes appear.

METHODS

Conventional MRI, diffusion tensor imaging (DTI), and DKI scans were performed for 90 cervical spondylosis patients on 1.5-T MR Siemens Magnetom aera after obtaining informed consent. Eight patients were excluded due to poor image quality. Fractional anisotropy (FA) colour maps and diffusion kurtosis (DK) maps corresponding to spinal cord cross sections at C2-C3 intervertebral disc level (control) and at the most stenotic levels were obtained. Modified Japanese Orthopaedic Association (mJOA) scoring was used for clinical assessment of the spinal cord function. The changes in DTI and DKI parameters and their correlation with mJOA scores were analysed by SPSS 23 software.

RESULTS

In our study, mean FA and mean kurtosis (MK) values at the stenotic level (0.54, 1.02) were significantly lower than values at the non-stenotic segment (0.70, 1.27). The mean diffusivity (MD) value at the stenotic segment (1.25) was significantly higher than in the non-stenotic segment (1.09). We also observed a strong positive correlation between mJOA score and FA and MK values and a negative correlation between mJOA score and MD values, suggesting a correlation of FA, MK, and MD with the clinical severity of the disease.

CONCLUSION

Addition of DTI and DKI sequences helps in early identification of the disease without any additional cost incurred by the patient.

Clinical and Research MRI Techniques for Assessing Spinal Cord Integrity in Degenerative Cervical Myelopathy-A Scoping Review

BACKGROUND

Degenerative cervical myelopathy (DCM) manifests as the primary cause of spinal cord dysfunction and is non-traumatic, chronic and progressive in nature. Decompressive surgery is typically utilised to halt further disability and neurological dysfunction. The limitations of current diagnostic options surrounding assessment and prognostic potential render DCM still largely a clinical diagnosis.

AIMS

To outline the limitations of current diagnostic techniques, present evidence behind novel quantitative MRI (qMRI) techniques for assessing spinal cord integrity in DCM and suggest future directions.

METHOD

Articles published up to November 2021 were retrieved from Medline, EMBASE and EBM using key search terms: spinal cord, spine, neck, MRI, magnetic resonance imaging, qMRI, T1, T2, T2*, R2*, DTI, diffusion tensor imaging, MT, magnetisation transfer, SWI, susceptibility weighted imaging, BOLD, blood oxygen level dependent, fMRI, functional magnetic resonance imaging, functional MRI, MRS, magnetic resonance spectroscopy.

RESULTS

A total of 2057 articles were retrieved with 68 articles included for analysis. The search yielded 2 articles on Quantitative T1 mapping which suggested higher T1 values in spinal cord of moderate-severe DCM; 43 articles on DTI which indicated a strong correlation of fractional anisotropy and modified Japanese Orthopaedic Association scores; 15 articles on fMRI (BOLD) which demonstrated positive correlation of functional connectivity and volume of activation of various connections in the brain with post-surgical recovery; 6 articles on MRS which suggested that Choline/N-acetylaspartate (Cho/NAA) ratio presents the best correlation with DCM severity; and 4 articles on MT which revealed a preliminary negative correlation of magnetisation transfer ratio with DCM severity. Notably, most studies were of low sample size with short timeframes within 6 months.

CONCLUSIONS

Further longitudinal studies with higher sample sizes and longer time horizons are necessary to determine the full prognostic capacity of qMRI in DCM.

Filtered Diffusion-Weighted MRI of the Human Cervical Spinal Cord: Feasibility and Application to Traumatic Spinal Cord Injury

BACKGROUND AND PURPOSE

In traumatic spinal cord injury, DTI is sensitive to injury but is unable to differentiate multiple pathologies. Axonal damage is a central feature of the underlying cord injury, but prominent edema confounds its detection. The purpose of this study was to examine a filtered DWI technique in patients with acute spinal cord injury.

MATERIALS AND METHODS

The MR imaging protocol was first evaluated in a cohort of healthy subjects at 3T (n = 3). Subsequently, patients with acute cervical spinal cord injury (n = 8) underwent filtered DWI concurrent with their acute clinical MR imaging examination <24 hours postinjury at 1.5T. DTI was obtained with 25 directions at a b-value of 800 s/mm². Filtered DWI used spinal cord-optimized diffusion-weighting along 26 directions with a "filter" b-value of 2000 s/mm² and a "probe" maximum b-value of 1000 s/mm². Parallel diffusivity metrics obtained from DTI and filtered DWI were compared.

RESULTS

The high-strength diffusion-weighting perpendicular to the cord suppressed signals from tissues outside of the spinal cord, including muscle and CSF. The parallel ADC acquired from filtered DWI at the level of injury relative to the most cranial region showed a greater decrease (38.71%) compared with the decrease in axial diffusivity acquired by DTI (17.68%).

CONCLUSIONS

The results demonstrated that filtered DWI is feasible in the acute setting of spinal cord injury and reveals spinal cord diffusion characteristics not evident with conventional DTI.

A Bibliometric Analysis and Visualization of Current Research Trends in the Treatment of Cervical Spondylotic Myelopathy

STUDY DESIGN

Bibliometric analysis.

OBJECTIVE

Cervical spondylotic myelopathy (CSM) has become the most common cause of spinal cord dysfunction. Many topics of CSM still remain controversial. This study aimed to illustrate the overall knowledge structure and development trends of CSM.

METHODS

Research data sets were acquired from the Web of Science database and the time span was defined as "2000 to 2019." VOS viewer and Citespace software was used to analyze the data and generate visualization knowledge maps. Annual trends of publications, distribution, H-index status, co-authorship status, and research hotspots were analyzed.

RESULTS

A total of 2367 publications met the requirement. The largest number of articles was from the United States, followed by Japan, China, Canada, and India. The highest H-index was found for articles from the United States. The highest number of articles was published in Spine. The cooperation between the countries, institutes, and authors were relatively weak. Cervical sagittal alignment, predictive factor, diffusion tensor imaging, and the natural history of CSM may become a frontier in this research field.

CONCLUSION

The number of publications showed an upward trend with a stable rise. Most of the publications are limited to a few countries and institutions with relatively weak interaction. The United States, Canada, Japan, China, and India have made significant contributions to the field of CSM. The United States is the country with the highest productivity, not only in quality but also in quantity. Cervical sagittal alignment, predictive factor, diffusion tensor imaging, and the natural history of CSM are the research hotspots in the recent years.

Quantitative Evaluation of the Diffusion Tensor Imaging Matrix Parameters and the Subsequent Correlation with the Clinical Assessment of Disease Severity in Cervical Spondylotic Myelopathy

Study Design

We performed a prospective observational study of 52 patients who were clinically suspected of cervical spondylotic myelopathy (CSM), based on the modified Japanese Orthopaedic Association (mJOA) score, and were referred for magnetic resonance imaging (MRI) of the cervical spine.

Purpose

To evaluate the quantitative parameters of the diffusion tensor imaging (DTI) matrix (fractional anisotropy [FA] and apparent diffusion coefficient [ADC] values) and determine the subsequent correlation with the clinical assessment of disease severity in CSM.

Overview of Literature

Conventional MRI is the modality of choice for the identification of cervical spondylotic changes and is known to have a low sensitivity for myelopathy changes. DTI is sensitive to disease processes that alter the water movement in the cervical spinal cord at a microscopic level beyond the conventional MRI.

Methods

DTI images were processed to produce FA and ADC values of the acquired axial slices with the regions of interest placed within the stenotic and non-stenotic segments. The final quantitative radiological derivations were matched with the clinical scoring system.

Results

Total 52 people (24 men and 28 women), mean age 53.16 years with different symptoms of myelopathy, graded as mild (n=11), moderate (n=25), and severe (n=16) as per the mJOA scoring system, underwent MRI of the cervical spine with DTI. In the most stenotic segments, the mean FA value was significantly lower (0.5009±0.087 vs. 0.655.7±0.104, p<0.001), and the mean ADC value was significantly higher (1.196.5±0.311 vs. 0.9370±0.284, p<0.001) than that in the non-stenotic segments. The overall sensitivity in identifying DTI metrics abnormalities was more with FA (87.5%) and ADC (75.0%) than with T2 weighted images (25%).

Conclusions

In addition to the routine MRI sequences, DTI metrics (FA value better than ADC) can detect myelopathy even in patients with a mild grade mJOA score before irreversible changes become apparent on routine T2 weighted imaging and thus enhance the clinical success of decompression surgery.

Microstructural Changes in Compressed Cervical Spinal Cord Are Consistent With Clinical Symptoms and Symptom Duration

STUDY DESIGN

A prospective study.

OBJECTIVE

To investigate the association between microstructural changes measured by diffusion tensor imaging (DTI) and clinical symptoms and their duration in patients with cervical spondylotic myelopathy (CSM) affected by single level.

SUMMARY OF BACKGROUND DATA

No report was reported regarding the association between the microstructural changes and the symptoms and their duration at single-level spinal cord compression.

METHODS

Twenty-nine consecutive patients with CSM and 29 normal subjects were enrolled in this study. DTI with tractography was performed on the cervical spinal cord. Clinical symptoms were evaluated using modified Japanese Orthopaedic Association (mJOA) scores for each patient, and the duration of clinical symptoms was noted based on the earliest instance of limb pain or numbness or weakness or bladder dysfunction. Mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from tractography images.

RESULTS

The mean FA value of the cervical compressed spinal cord was significantly lower than the FA of the normal population (P < 0.001). The mean ADC value in the cervical compressed spinal cord was obviously higher than those of normal cervical spinal cord (P < 0.001). In the CSM patients, a significant positive association was observed between FA values and mJOA scores (P < 0.001). However, there were a notable negative association between mJOA scores and ADC values (P < 0.001), and between mJOA scores and symptom duration (P < 0.001).

CONCLUSION

These results illustrate DTI can measure the micostructural changes of cervical spinal cord and DTI parameters are potential biomarkers for spinal cord dysfunction in patients with CSM.

LEVEL OF EVIDENCE

3.

Apparent diffusion coefficient as an indicator of spinal cord compression due to anterior atlanto-axial subluxation in rheumatoid arthritis patients

PURPOSE

The aim of this retrospective study was to evaluate the apparent diffusion coefficient (ADC) as a potential parameter of spinal cord damage in cervical spine instability at the atlanto-axial level in rheumatoid arthritis (RA) patients.

METHODS

One hundred and six RA patients were included in the study. MRI examinations were performed with 1.5T scanner. The ADC was measured at six locations in the cervical spinal cord at the height of the first six cervical vertebrae (from C-1 to C-6). The ADC values were assessed in 2 groups: with and without anterior atlanto-axial subluxation (AAS) diagnosed on plain radiographs. Correlations between ADC values and radiographic measurements and RA activity indicators were evaluated.

RESULTS

The ADC values at C1 level (ADC₁) was higher in the group with anterior AAS than in the group without AAS (p < 0.001). Statistically significant moderate positive correlation between ADC₁ and anterior atlanto-axial diameter interval AADI (rho = 0.58; p < 0.008) was found as well as statistically significant weak negative correlation between ADC₁ and posterior atlanto-axial diameter interval PADI (rho =  - 0.34; p < 0.008).

CONCLUSIONS

The conducted study demonstrates the applicability of the ADC maps in the identification of spinal cord compression due to anterior AAS in RA patients. The results encourage the practical use of the ADC as an additional parameter in the qualification for surgical treatment. These slides can be retrieved under Electronic Supplementary Material.