Accuracy of Diffusion Tensor Imaging for Diagnosing Cervical Spondylotic Myelopathy in Patients Showing Spinal Cord Compression

Diffusion Tensor Imaging in Diagnosing and Evaluating Degenerative Cervical Myelopathy: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review.

OBJECTIVE

Degenerative cervical myelopathy (DCM) is a common spinal cord disorder necessitating surgery. We aim to explore how effectively diffusion tensor imaging (DTI) can distinguish DCM from healthy individuals and assess the relationship between DTI metrics and symptom severity.

METHODS

We included studies with adult DCM patients who had not undergone decompressive surgery and implemented correlation analyses between DTI parameters and severity, or compared healthy controls and DCM patients.

RESULTS

57 studies were included in our meta-analysis. At the maximal compression (MC) level, fractional anisotropy (FA) exhibited lower values in DCM patients, while apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) were notably higher in the DCM group. Moreover, our investigation into the diagnostic utility of DTI parameters disclosed high sensitivity, specificity, and area under the curve values for FA (.84, .80, .83 respectively) and ADC (.74, .84, .88 respectively). Additionally, we explored the correlation between DTI parameters and myelopathy severity, revealing a significant correlation of FA (.53, 95% CI:0.40 to .65) at MC level with JOA/mJOA scores.

CONCLUSION

Current guidelines for DCM suggest decompressive surgery for both mild and severe cases. However, they lack clear recommendations on which mild DCM patients might benefit from conservative treatment vs immediate surgery. ADC's role here could be pivotal, potentially differentiating between healthy individuals and DCM. While it may not correlate with symptom severity, it might predict surgical outcomes, making it a valuable imaging biomarker for clearer management decisions in mild DCM.

Cervical Spondylotic Myelopathy: From the World Federation of Neurosurgical Societies (WFNS) to the Italian Neurosurgical Society (SINch) Recommendations

Cervical spondylotic myelopathy (CSM) is a progressively growing pathology to afford by a spinal surgeon due to the aging of the population, associated with better treatment management and the best diagnosis and treatment solutions are greatly discussed. Nowadays that scientific literature is progressively increasing to identify the gold standard in diagnosis and treatment can be very challenging. This is particularly evident in spinal surgery with many different indications not only in different countries but also in the same local reality. In this scenario, many neurosurgical societies works to identify some guideline or recommendations to help spinal surgeons in daily practice. Furthermore, in an era in which legal issues are increasingly present in clinical practice to have some indications globally accepted can be very useful. World Federation of Neurosurgical Societies (WFNS) few years ago starts this process creating a list of recommendations originating from a worldwide steering committee to respect all the local reality. The spinal section of Italian Neurosurgical Society decides to adopt the WFNS recommendations with some revision basing on Italian scenario. The steering committee of the Spinal Section of Italian Neurosurgical Society identify 7 groups to review the literature of the last 10 years about different topics on CSM and to analyses the WFNS recommendations to adapt it to the Italian daily practice. The statements were discussed and voted in 2 sessions to obtain the final version. A list of recommendations on natural course and clinical presentation; diagnostic tests; conservative and surgical treatment; anterior, posterior and combined surgical treatment; role of neurophysiological monitoring and follow-up and outcome was created with only few new or revised statements respect the ones of WFNS. The Spine Section of Italian Neurosurgical Society create a list of recommendations that represent the more contemporary treatment concepts for CSM as presented in the highest quality clinical literature and best clinical practices available on this subject.

Diffusion Tensor Imaging in Spinal Cord Injury: A Review

Magnetic resonance diffusion tensor imaging (DTI) is a recent technique that can measure the direction and magnitude of diffusion of water. It is widely being utilized to evaluate several brain and spinal cord pathologies. The objective of this review is to evaluate the importance of the DTI in patients with spinal cord injury (SCI). It aims to review various articles on DTI SCI and includes both animal and human studies. This will help to describe the current status of the clinical applications of DTI and show its potential as a helpful instrument in clinical practice. The PubMed database was searched for articles relating to the application of DTI in SCI. Relevant articles were also used for the review. A variety of DTI parameters have been studied in various articles. The standard parameters are fractional anisotropy (FA) values, apparent diffusion coefficient (ADC) values, radial diffusivity values, and axial diffusivity values, followed by tractography. FA and ADC values are the most commonly used parameters. The findings observed in most of the studies are increased FA and reduced ADC values following injury to the spinal cord. DTI data metrics possess the potential to become a potent clinical tool in patients with SCI. It is helpful for diagnosis, prognosis, treatment planning, as well as to evaluate the recovery. Nonetheless, to overcome the limitations and determine its reliability clinically, more research has to be performed.

Degeneration of the Sensorimotor Tract in Degenerative Cervical Myelopathy and Compensatory Structural Changes in the Brain

Degenerative cervical myelopathy is a progressive neurodegenerative disease, that has become increasingly prevalent in the aging population worldwide. The current study determined the factors affecting degeneration in the sensorimotor tract with degenerative cervical myelopathy and its relationship with brain structure. We divided patients into hyperintensity (HS) and non-hyperintensity (nHS) groups and measured the fractional anisotropy and apparent diffusion coefficients of the lateral corticospinal tract (CST), fasciculus gracilis and fasciculus cuneatus (FGC). Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) techniques were used to estimate brain structure changes. Correlation of the modified Japanese Orthopaedic Association (mJOA) score, light touch, pinprick, motor score, and fractional anisotropy (FA) ratios of the CST at different levels were analyzed. Compared to healthy controls, the FA ratios of CST in the HS and nHS groups were decreased at all levels, and the apparent diffusion coefficient (ADC) ratio was increased only at C4/5 levels in the HS group. The FA ratio of FGC was decreased at the C3/4 and C4/5 levels in the HS group and only decreased at the C4/5 level in the nHS group. The ADC ratio was decreased only at the C4/5 level in the HS group. VBM analysis revealed that the volume of the precentral gyrus, postcentral gyrus, and paracentral lobule increased in patients compared to controls. TBSS analysis found no statistical significance between the sensory and motor tracts in white matter. The volume of clusters in HS and nHS groups negatively correlated with the C1/2 FA ratio of the CST. The results showed that the degeneration distance of the CST was longer than the FGC, and the degeneration distance was related to the degree of compression and spinal cord damage. Structural compensation and the neurotrophin family may lead to enlargement of the brain.

Ultrahigh-b diffusion-weighted imaging for quantitative evaluation of myelination in shiverer mouse spinal cord

PURPOSE

To perform a quantitative evaluation of myelination on WT and myelin-deficient (shiverer) mouse spinal cords using ultrahigh-b diffusion-weighted imaging (UHb-DWI).

METHODS

UHb-DWI of ex vivo on spinal cord specimens of two shiverer (C3HeB/FeJ-shiverer, homozygous genotype for MbP_shi ) and six WT (Black Six, C3HeB/FeJ) mice were acquired using 3D multishot diffusion-weighted stimulated-echo EPI, a homemade RF coil, and a small-bore 7T MRI system. Imaging was performed in transaxial plane with 75 × 75 μm² in-plane resolution, 1-mm-slice thickness, and radial DWI using b_max = 42,890 s/mm² . Histological evaluation was performed on upper thoracic sections using optical and transmission electron microscopy. Numerical Monte Carlo simulations (MCSs) of water diffusion were performed to facilitate interpretation of UHb-DWI signal-b curves.

RESULTS

The white matter ultrahigh-b radial DWI (UHb-rDWI) signal-b curves of WT mouse cords behaved biexponentially with high-b diffusion coefficient D_H < 0.020 × 10^-3 mm² /s. However, as expected with less myelination, the signal-b of shiverer mouse cords behaved monoexponentially with significantly greater D_H = 0.162 × 10^-3 , 0.142 × 10^-3 , and 0.164 × 10^-3 mm² /s at anterodorsal, posterodorsal, and lateral columns, respectively. The axial DWI signals of all mouse cords behaved monoexponentially with D = (0.718-1.124) × 10^-3 mm² /s. MCS suggests that these elevated D_H are mainly induced by increased water exchange at the myelin sheath. Microscopic results were consistent with the UHb-rDWI findings.

CONCLUSION

UHb-DWI provides quantitative differences in myelination of spinal cords from myelin-deficit shiverer and WT mice. UHb-DWI may become a powerful tool to evaluate myelination in demyelinating disease models that may translate to human diseases, including multiple sclerosis.

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.

Diffusion tensor imaging of the spinal cord status post trauma

Background

Since its development in 1994, diffusion tensor imaging (DTI) has been successfully used to assess structural and functional changes to neurological tissue within the central nervous system. Namely, DTI is a noninvasive magnetic resonance imaging (MRI)-based technique that uses anisotropic diffusion to visualize and estimate the organization of white matter in neuronal tissue. It has been used to study various spinal pathologies including neoplastic diseases, degenerative myelopathy, demyelinating diseases, and infections involving the spinal cord. However, due to technical uncertainties and experimental limitations, DTI has rarely been clinically applied to assess trauma-related spinal pathologies.

Methods

An extensive review of the published literature on DTI was performed utilizing PubMed, OVID Medline, and EMBASE journals. Terms used for the search included DTI and spine trauma.

Results

The search yielded full text English language-related articles regarding DTIs application, limitations, and functional outcomes secondary to spinal trauma.

Conclusion

DTI relies on anisotropy in CNS tissues to determine the spatial orientation of surrounding axon tracts and define anatomical boundaries. Diffusion along three principle axes is used to calculate the following four DTI indices; fractional anisotropy, apparent diffusion coefficient (ADC), longitudinal ADC, and transverse ADC. Using DTI as a diagnostic tool status, post spine trauma has proven useful in examining the morphological and physiological extent of spinal lesions beyond conventional MRI. Experimental studies are now utilizing DTI to analyze the severity of spinal cord trauma during the hyperacute phase and may potentially be used to providing additional diagnostic information for improved treatment efficiency (e.g., as shown during the stem cell therapy trials).

Multi-shot echo-planar diffusion tensor imaging in cervical spondylotic myelopathy

AIMS

The aim of this study was to use diffusion tensor imaging (DTI) to investigate changes in diffusion metrics in patients with cervical spondylotic myelopathy (CSM) up to five years after decompressive surgery. We correlated these changes with clinical outcomes as scored by the Modified Japanese Orthopedic Association (mJOA) method, Neck Disability Index (NDI), and Visual Analogue Scale (VAS).

METHODS

We used multi-shot, high-resolution, diffusion tensor imaging (ms-DTI) in patients with cervical spondylotic myelopathy (CSM) to investigate the change in diffusion metrics and clinical outcomes up to five years after anterior cervical interbody discectomy and fusion (ACDF). High signal intensity was identified on T2-weighted imaging, along with DTI metrics such as fractional anisotropy (FA). MJOA, NDI, and VAS scores were also collected and compared at each follow-up point. Spearman correlations identified correspondence between FA and clinical outcome scores.

RESULTS

Significant differences in mJOA scores and FA values were found between preoperative and postoperative timepoints up to two years after surgery. FA at the level of maximum cord compression (MCL) preoperatively was significantly correlated with the preoperative mJOA score. FA postoperatively was also significantly correlated with the postoperative mJOA score. There was no statistical relationship between NDI and mJOA or VAS.

CONCLUSION

ms-DTI can detect microstructural changes in affected cord segments and reflect functional improvement. Both FA values and mJOA scores showed maximum recovery two years after surgery. The DTI metrics are significantly associated with pre- and postoperative mJOA scores. DTI metrics are a more sensitive, timely, and quantifiable surrogate for evaluating patients with CSM and a potential quantifiable biomarker for spinal cord dysfunction. Cite this article: Bone Joint J 2020;102-B(9):1210-1218.

The Evaluation and Prediction of Laminoplasty Surgery Outcome in Patients with Degenerative Cervical Myelopathy Using Diffusion Tensor MRI

BACKGROUND AND PURPOSE

DTI has been proved valuable for the diagnosis of degenerative cervical myelopathy, whereas its capacity for predicting the outcome of surgery is still under debate. Here we conduct a prospective cohort study to analyze the capacity of DTI for evaluating and predicting laminoplasty surgery outcome for degenerative cervical myelopathy.

MATERIALS AND METHODS

We recruited 55 patients with degenerative cervical myelopathy who underwent DTI before surgery and at 3- and 6-month follow-up stages, and 20 healthy subjects. For clinical assessment, the modified Japanese Orthopedic Association scale was recorded for each patient at different stages. DTI metrics were compared between patients before surgery and healthy subjects. Spearman correlation and receiver operating characteristic were used to analyze the evaluation and prediction capacity of DTI for the modified Japanese Orthopedic Association scale, respectively. We analyzed different vertebral levels: maximal compression level, average of all compression levels, and C2 level.

RESULTS

DTI metrics were significantly different between patients before surgery and healthy subjects. Before surgery, DTI for the maximal compression level or DTI for the average of all compression levels had no significant correlation with the modified Japanese Orthopedic Association scale. For all stages, DTI at the C2 level was correlated with the modified Japanese Orthopedic Association scale. DTI metrics at the C2 level before surgery were significantly correlated with the postoperative modified Japanese Orthopedic Association scale recovery rate. Receiver operating characteristic analysis demonstrated that fractional anisotropy at C2 was capable of predicting the postoperative modified Japanese Orthopedic Association scale recovery rate (P = .04).

CONCLUSIONS

The DTI metrics before laminoplasty surgery, especially fractional anisotropy at the C2 level, have the potential for evaluating and predicting the degenerative cervical myelopathy surgery outcome.

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.

Correlation of Clinical Findings in Acute Spinal Injury Patients with Magnetic Resonance Including Diffusion Tensor Imaging and Fiber Tractography

Introduction

Many types of research are being carried out in the fields of understanding of the pathogenesis, early recognition, and improving the outcomes after spinal cord injury (SCI). Diffusion tensor imaging (DTI) is one of the modalities used in vivo microstructural assessment of SCI. The aim of the present study is to evaluate the role of DTI imaging and fiber tractography in acute spinal injury with clinical profile and neurological outcome.

Methods

The study was carried out on twenty-five patients of acute spinal cord injury who presented within 48 hours of injury and completed minimum of six months follow-up.

Results

The mean age of patients was 37.32±13.31 years and male & female ratio of 18:7. Total MIS score was 91.64±6.0 initially which improved to 96.92±3.68 after 3 months and 99.4±1.35 after 6 months. Total SIS score was similar at all the time intervals i.e. 224±0. Maximum subjects 14(56%) were classified into AIS C and 5(20%) into AIS D whereas only 6(24%) subjects were having no deficit (AIS E). At the end of 6 months, 13(52%) subjects had no deficit (AIS E). Mean fractional anisotropy (FA) initially was 0.451 (± 0.120) but after 6 months, it increased to 0.482 (± 0.097) (p<0.001). The mean apparent diffusion coefficient (ADC) initially was 3.13 (± 2.68) but after 6 months, it decreased to 3.06 (± 2.68) and this change was found to be statistically highly significant (p<0.001). Mean anisotropy index (AI) initially was 0.420 (± 0.245) but after 6 months, it increased to 0.430 (± 3.41) and this change was found to be statistically significant (p<0.01).

Conclusions

DTI is a sensitive tool to detect neurological damage in SCI and subsequent neurological recovery. FA correlated with ASIA impairment scale. It can be useful as an adjunct to conventional MRI for better evaluation and predicting prognosis in SCI patients.

Diffusion Tensor Imaging Characteristics in Hirayama Disease: Case Report and Review of the Literature

BACKGROUND

Hirayama disease (HD) is a rare focal amyotrophy, commonly reported in adolescent Asian males and characterized by unilateral or asymmetric distal upper extremity weakness. This disease exhibits an indolent course of progression over the initial 3-4 years, followed by a stage of stabilization. The diagnosis is confirmed by demonstration of enhanced posterior epidural space and dynamic spinal cord compression on cervical flexion magnetic resonance imaging. Diffusion tensor imaging (DTI) is a functional imaging modality, which can potentially be utilized in the diagnosis of HD.

CASE DESCRIPTION

We hereby report 2 young male patients who had presented to us with bilateral asymmetric upper extremity weakness. In both patients, magnetic resonance imaging of cervical spine revealed spinal cord atrophy or myelomalacia, anterior displacement of posterior thecal sac, and T2 hyperintense posterior epidural space, all of which were more evident in flexed position. On DTI, we could observe reduced fractional anisotropy in cervical flexion, as compared with neutral.

CONCLUSIONS

DTI tractography and reduced fractional anisotropy in cervical flexion can serve as potential indicators for the diagnosis of HD. Large-scale studies in the future are necessary to identify the potential role of this modality in surgical decision-making and in the assessment of prognosis in patients with HD.

The role of diffusion tensor imaging in the diagnosis, prognosis, and assessment of recovery and treatment of spinal cord injury: a systematic review

OBJECTIVEDiffusion tensor imaging (DTI) is an MRI tool that provides an objective, noninvasive, in vivo assessment of spinal cord injury (SCI). DTI is significantly better at visualizing microstructures than standard MRI sequences. In this imaging modality, the direction and amplitude of the diffusion of water molecules inside tissues is measured, and this diffusion can be measured using a variety of parameters. As a result, the potential clinical application of DTI has been studied in several spinal cord pathologies, including SCI. The aim of this study was to describe the current state of the potential clinical utility of DTI in patients with SCI and the challenges to its use as a tool in clinical practice.METHODSA search in the PubMed database was conducted for articles relating to the use of DTI in SCI. The citations of relevant articles were also searched for additional articles.RESULTSAmong the most common DTI metrics are fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity. Changes in these metrics reflect changes in tissue integrity. Several DTI metrics and combinations thereof have demonstrated significant correlations with clinical function both in model species and in humans. Its applications encompass the full spectrum of the clinical assessment of SCI including diagnosis, prognosis, recovery, and efficacy of treatments in both the spinal cord and potentially the brain.CONCLUSIONSDTI and its metrics have great potential to become a powerful clinical tool in SCI. However, the current limitations of DTI preclude its use beyond research and into clinical practice. Further studies are needed to significantly improve and resolve these limitations as well as to determine reliable time-specific changes in multiple DTI metrics for this tool to be used accurately and reliably in the clinical setting.

Plasma VDBP, 25(OH)D, and GSH levels predict surgical outcome in patients with cervical spondylotic myelopathy

This study intends to investigate the predictive values of plasma Vitamin D-binding protein (VDBP), 25-hydroxyvitamin D [25(OH)D], and glutathione (GSH) levels in the outcome of cervical spondylotic myelopathy (CSM) surgery. Surgery outcomes of 236 CSM patients were determined. Recovery rate was calculated according to Japanese Orthopaedic Association (JOA) scores during follow-up. CSM patients with a recovery rate >50% were assigned with good prognosis and the rest were with fair prognosis. Preoperative and postoperative neurologic function scores were compared among groups. Plasma VDBP and 25(OH)D levels, as well as GSH levels were measured by ELISA and glutathione reductase recycling assay, respectively. Pearson's correlation coefficient was performed to analyze the correlation among plasma VDBP, 25(OH)D, and GSH levels. Receiver operating characteristic (ROC) curve was applied to evaluate the predictive value of plasma VDBP, 25(OH)D, and GSH levels for surgical outcome. Logistic regression model was used to analyze risk factors for surgical outcome. Compared with those with fair prognosis, CSM patients with good prognosis group exhibited higher postoperative neurologic function scores, plasma VDBP, 25(OH)D, and GSH levels, and better improvements in spinal cord compression and motions of the cervical vertebra. Plasma VDBP, 25(OH)D, and GSH levels were favorable prognostic factors for CSM surgical outcome. The sensitivity and specificity of plasma VDBP, plasma 25(OH)D, and plasma GSH were 89.8% and 91.7%, 85.8% and 84.4%, and 79.5% and 91.7%, respectively. Our study provides evidence that higher plasma VDBP, 25(OH)D, and GSH levels may predict better surgical outcome in CSM patients.

Predictive value of flexion and extension diffusion tensor imaging in the early stage of cervical myelopathy

PURPOSE

Diffusion tensor imaging (DTI) in flexion (F) and extension (E) may serve as a sensitive diagnostic tool in early symptoms of myelopathy. The aim of this study was to compare values of water diffusion parameters on dynamic cervical DTI in early stage of myelopathy.

METHODS

Study enrolled 10 patients with an early stage of cervical myelopathy, in grade I/II of Nurick classification. All subjects were scanned with flexion-extension 3T MRI. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), RD (radial diffusivity), AD (axial diffusivity) and TRACEW (trace diffusion) were measured at C2, compression level (CL) and C7. Parameters were compared between 3 levels and F and E positions.

RESULTS

Flexion DTI revealed significant difference only for TRACEW between C2 and C7 (105.8 ± 18.9 vs. 83.7 ± 14, respectively; p = 0.0029). Extension DTI showed differences for ADC between CL and C7 (1378.9 ± 381.8 vs. 1227.2 ± 269.2; p = 0.001), reduced FA from 664.6 ± 56.3 at C2 down to 553.1 ± 75.5 (p = 0.001) at CL and 584.7 ± 40.7 at C7 (p = 0.002). Differences of RD in E were significant through all levels and reached 612.9 ± 105.1, 955.3 ± 319.4 and 802.1 ± 194.1 at C2, CL and C7, respectively. TRACEW lowered from 92.3 ± 14.4 at C2 to 66.9 ± 21.1 at CL (p = 0.0001) and 64.4 ± 15.5 at C7 (p = 0.0002). Comparison of DTI between F and E showed differences for all parameters except AD. RD was significantly higher in E at CL (p = 0.003) and C7 (0.013), but TRACEW increased in F at CL by 27.4% (p = 0.001) and at C7 by 23.1% (p = 0.013). FA was reduced at CL in E (p = 0.027) and similarly ADC in F (p = 0.048).

CONCLUSION

Dynamic DTI of the cervical spine is feasible and can detect subtle spinal cord damage of functional relevance in cervical myelopathy. A marked increase of RD and decrease of FA and TRACEW values in extension were found to be indicative for an early structural cord injury in myelopathy.

Usefulness of conventional magnetic resonance imaging, diffusion tensor imaging and neurite orientation dispersion and density imaging in evaluating postoperative function in patients with cervical spondylotic myelopathy

Objective

The objective of this study was to evaluate the usefulness of T2 high signal intensity (T2-HSI) and decreased anteroposterior diameter (APD), diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) in evaluating postoperative cervical cord function.

Methods

The study included 57 postoperative cervical spondylotic myelopathy patients. Clinical evaluation and functional recovery assessments were performed using the modified Japanese Orthopaedic Association (mJOA) score and recovery rate. The presence of T2-HSI and decreased APD was recorded for exploring the relevance. Spearman correlation was applied to investigate the relationships between DTI and NODDI metrics and mJOA score. Multiple comparisons of T2 signal intensity, APD and diffusion metrics were evaluated by using multiple linear regression.

Results

Only the recovery rate was significantly different between T2-HSI and non-T2-HSI (nT2-HSI) patients (χ² = 4.466, p = 0.045). Significant differences were not observed between cervical cords with and without decreased APD. Diffusion metrics, including fractional anisotropy (p = 0.0005), mean diffusivity (p = 0.0008), radial diffusivity (p = 0.0003) and intracellular volume fraction (p = 0.001), were significantly correlated with mJOA score. The ability of T2 signal intensity (p = 0.421) and APD (p = 0.420) to evaluate the postoperative function was inferior to that of fractional anisotropy (p = 0.002), mean diffusivity (p = 0.001), radial diffusivity (p = 0.001) and intracellular volume fraction (p = 0.004).

Conclusion

Conventional magnetic resonance imaging signs could be considered as a reference to make an approximate assessment, whereas DTI and NODDI could be better quantitative tools for evaluating the postoperative function and may help in interpreting residual symptoms.

The translational potential of this article

DTI and NODDI could provide reliable postoperative evaluation and analysis for cervical spondylotic myelopathy patients.

Highly Accurate Analysis of the Cervical Neural Tract of the Elderly Using ZOOM DTI

Background/Aims

To investigate the fractional anisotropy (FA) values of the cervical spinal cord in elderly individuals using zonally magnified oblique multislice (ZOOM) diffusion tensor imaging (DTI).

Methods

Fourteen healthy elderly volunteers (group E) and 10 young volunteers (group Y) were enrolled. We assessed the FA, apparent diffusion coefficient (ADC), and λ₁–λ₃ values using 3-T magnetic resonance imaging. The region of interest was contoured entirely inside the spinal cord, with no gray/white matter distinction, in order to avoid including the cerebrospinal fluid.

Results

As lower cervical levels were approached, the FA values gradually decreased, while the ADC values increased. The mean FA values at each cervical level were as follows in groups E and Y: 0.71 and 0.70 at the C2/3 level, 0.66 and 0.66 at the C3/4 level, 0.63 and 0.62 at the C4/5 level, 0.57 and 0.57 at the C5/6 level, and 0.58 and 0.57 at the C6/7 level, respectively. The mean ADC values in groups E and Y were 1.06 and 0.99 at the C2/3 level, 1.05 and 1.06 at the C3/4 level, 1.14 and 1.06 at the C4/5 level, 1.18 and 1.21 at the C5/6 level, and 1.39 and 1.46 at the C6/7 level, respectively. There were no significant differences between the elderly and young participants.

Conclusion

In both asymptomatic elderly and young individuals, the FA values gradually decreased and the ADC values increased moving towards lower cervical levels. Age did not affect the FA values, even though mild cord compression was evident due to spondylotic changes. ZOOM DTI has the potential to provide more information than conventional DTI.

Selection and Reporting of Statistical Methods to Assess Reliability of a Diagnostic Test: Conformity to Recommended Methods in a Peer-Reviewed Journal

Objective

To evaluate the frequency and adequacy of statistical analyses in a general radiology journal when reporting a reliability analysis for a diagnostic test.

Materials and Methods

Sixty-three studies of diagnostic test accuracy (DTA) and 36 studies reporting reliability analyses published in the Korean Journal of Radiology between 2012 and 2016 were analyzed. Studies were judged using the methodological guidelines of the Radiological Society of North America-Quantitative Imaging Biomarkers Alliance (RSNA-QIBA), and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative. DTA studies were evaluated by nine editorial board members of the journal. Reliability studies were evaluated by study reviewers experienced with reliability analysis.

Results

Thirty-one (49.2%) of the 63 DTA studies did not include a reliability analysis when deemed necessary. Among the 36 reliability studies, proper statistical methods were used in all (5/5) studies dealing with dichotomous/nominal data, 46.7% (7/15) of studies dealing with ordinal data, and 95.2% (20/21) of studies dealing with continuous data. Statistical methods were described in sufficient detail regarding weighted kappa in 28.6% (2/7) of studies and regarding the model and assumptions of intraclass correlation coefficient in 35.3% (6/17) and 29.4% (5/17) of studies, respectively. Reliability parameters were used as if they were agreement parameters in 23.1% (3/13) of studies. Reproducibility and repeatability were used incorrectly in 20% (3/15) of studies.

Conclusion

Greater attention to the importance of reporting reliability, thorough description of the related statistical methods, efforts not to neglect agreement parameters, and better use of relevant terminology is necessary.

Predictors of symptomatic myelopathy in degenerative cervical spinal cord compression

OBJECTIVES

To update a previously established list of predictors for neurological cervical cord dysfunction in nonmyelopathic degenerative cervical cord compression (NMDCCC).

MATERIAL AND METHODS

A prospective observational follow-up study was performed in a cohort of 112 consecutive NMDCCC subjects (55 women and 57 men; median age 59 years, range 40-79 years), either asymptomatic (40 subjects) or presenting with cervical radiculopathy or cervical pain (72 subjects), who had completed a follow-up of at least 2 years (median duration 3 years). Development of clinical signs of degenerative cervical myelopathy (DCM) as the main outcome was monitored and correlated with a large number of demographic, clinical, electrophysiological, and MRI parameters including diffusion tensor imaging characteristics (DTI) established at entry.

RESULTS

Clinical evidence of the first signs and symptoms of DCM were found in 15 patients (13.4%). Development of DCM was associated with several parameters, including the clinical (radiculopathy, prolonged gait and run-time), electrophysiological (SEP, MEP and EMG signs of cervical cord dysfunction), and MRI (anteroposterior diameter of the cervical cord and cervical canal, cross-sectional area, compression ratio, type of compression, T2 hyperintensity). DTI parameters showed no significant predictive power. Multivariate analysis showed that radiculopathy, cross-sectional area (CSA) ≤ 70.1 mm², and compression ratio (CR) ≤ 0.4 were the only independent significant predictors for progression into symptomatic myelopathy.

CONCLUSIONS

In addition to previously described independent predictors of DCM development (radiculopathy and electrophysiological dysfunction of cervical cord), MRI parameters, namely CSA and CR, should also be considered as significant predictors for development of DCM.

Does the Reporting Quality of Diagnostic Test Accuracy Studies, as Defined by STARD 2015, Affect Citation?

Objective

To determine the rate with which diagnostic test accuracy studies that are published in a general radiology journal adhere to the Standards for Reporting of Diagnostic Accuracy Studies (STARD) 2015, and to explore the relationship between adherence rate and citation rate while avoiding confounding by journal factors.

Materials and Methods

All eligible diagnostic test accuracy studies that were published in the Korean Journal of Radiology in 2011–2015 were identified. Five reviewers assessed each article for yes/no compliance with 27 of the 30 STARD 2015 checklist items (items 28, 29, and 30 were excluded). The total STARD score (number of fulfilled STARD items) was calculated. The score of the 15 STARD items that related directly to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 was also calculated. The number of times each article was cited (as indicated by the Web of Science) after publication until March 2016 and the article exposure time (time in months between publication and March 2016) were extracted.

Results

Sixty-three articles were analyzed. The mean (range) total and QUADAS-2-related STARD scores were 20.0 (14.5–25) and 11.4 (7–15), respectively. The mean citation number was 4 (0–21). Citation number did not associate significantly with either STARD score after accounting for exposure time (total score: correlation coefficient = 0.154, p = 0.232; QUADAS-2-related score: correlation coefficient = 0.143, p = 0.266).

Conclusion

The degree of adherence to STARD 2015 was moderate for this journal, indicating that there is room for improvement. When adjusted for exposure time, the degree of adherence did not affect the citation rate.