Magnetic resonance imaging assessment of degenerative cervical myelopathy: a review of structural changes and measurement techniques

Alterations in Intramedullary T2-weighted Increased Signal Intensity following Laminoplasty in Cervical Spondylotic Myelopathy Patients: Comparison Between Pre- and Postoperative Magnetic Resonance Images

STUDY DESIGN

A prospective comparative imaging study.

OBJECTIVE

This study investigated whether the postoperative classification of and alterations in increased signal intensity (ISI) of the spinal cord reflected the postoperative severity of symptoms and surgical outcomes in cervical spondylotic myelopathy (CSM) patients.

SUMMARY OF BACKGROUND DATA

Although ISI on performing magnetic resonance imaging (MRI) is observed in CSM patients, alterations in ISI have not been investigated. The association of postoperative ISI with surgical outcomes in CSM patients remains controversial.

METHODS

Totally, 505 consecutive CSM patients (311 males) with a mean age of 66.6 (range, 41-91) years were enrolled. All were treated with laminoplasty and underwent MRI scans: preoperatively and after an average of 26.5 months postoperatively (range 12-66 months). ISI was classified pre- and postoperatively into three groups based on sagittal T2-weighted magnetic resonance images: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). The patients' pre- and postoperative neurological statuses were evaluated using the Japanese Orthopaedic Association scoring system for cervical myelopathy (JOA score) and other quantifiable tests, including the 10-s grip and release (10-s G&R) test and 10-s step test.

RESULTS

Preoperatively, 168 patients had Grade 0 ISI, 169 had Grade 1, and 168 had Grade 2; postoperatively, 210 patients had Grade 0 ISI, 94 had Grade 1, and 201 had Grade 2. Patients with postoperative Grade 0 ISI had a better postoperative JOA score, recovery rate, and 10-s G&R and 10-s step test scores than those with other grades. The postoperative ISI grade improved in 66 patients (13.1%), worsened in 57 (11.3%), and remained unchanged in 382 (75.6%).

CONCLUSION

Postoperative ISI partially reflects postoperative symptoms and surgical outcomes. Alterations in ISI were observed postoperatively in 123 patients (24.4%) and were not correlated with surgical outcomes.

LEVEL OF EVIDENCE

2.

Degenerative findings on MRI of the cervical spine: an inter- and intra-rater reliability study

Background

Knowledge about the assessment reliability of common cervical spine changes is a prerequisite for precise and consistent communication about Magnetic Resonance Imaging (MRI) findings. The purpose of this study was to determine the inter- and intra-rater reliability of degenerative findings when assessing cervical spine MRI.

Methods

Fifty cervical spine MRIs from subjects with neck pain were used. A radiologist, a chiropractor and a second-year resident of rheumatology independently assessed kyphosis, disc height, disc contour, vertebral endplate signal changes, spinal canal stenosis, neural foraminal stenosis, and osteoarthritis of the uncovertebral and zygapophyseal joints. An evaluation manual was composed containing classifications and illustrative examples, and ten of the MRIs were evaluated twice followed by consensus meetings to refine the classifications. Next, the three readers independently assessed the full sample. Reliability measures were reported using prevalence estimates and unweighted kappa (Κ) statistics.

Results

The overall inter-rater reliability was substantial (Κ ≥ 0.61) for the majority of variables and moderate only for zygapophyseal osteoarthritis (Κ = 0.56). Intra-rater reliability estimates were higher for all findings.

Conclusions

The present classifications for some of the most common cervical degenerative findings yielded mainly substantial inter-rater reliability estimates and substantial to almost perfect intra-rater reliability estimates. .

Trial registration

Regional Data Protection Agency (J.no. 1-16-02-86-16). The letter of exemption from the Regional Ethical Committee is available from the author on request (case no. 86 / 2017).

Tract-Specific Volume Loss on 3T MRI in Patients With Cervical Spondylotic Myelopathy

STUDY DESIGN

Case-control.

OBJECTIVE

The aim of this study was to understand the role of high-resolution magnetic resonance (MR) in identifying regional cord volume loss in cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Preliminary studies suggest that compression of the ventral region of the cord may contribute disproportionately to CSM symptomology; however, tract-specific data are lacking in the CSM population. The current study is the first to use 3T MR imaging (MRI) images of CSM patients to determine specific volume loss at the level of detail of individual descending white matter tracts.

METHODS

Twelve patients with CSM and 14 age-matched were enrolled prospectively and underwent 3-Tesla MRI of the cervical spine. Using the high-resolution images of the spinal cord, straightening and alignment with a template was performed and specific spinal cord tract volumes were measured using Spinal Cord Tool-box version 3.0.7. Modified Japanese orthopedic association (mJOA) and Nurick disability scores were collected in a prospective manner and were analyzed in relation to descending spinal tract volumes.

RESULTS

Having CSM was predicted by anterior/posterior diameter, eccentricity of the cord [odds ratio (OR) 0.000000621, P = 0.004], ventral reticulospinal tract volume (OR 1.167, P = 0.063), lateral corticospinal tract volume (OR 1.034, P = 0.046), rubrospinal tract volume (OR 1.072, P = 0.011), and ventrolateral reticulospinal tract volume (OR 1.474, P = 0.005) on single variable logistic regression. Single variable linear regression showed decreases in anterior/posterior spinal cord diameter (P = 0.022), ventral reticulospinal tract volumes (P = 0.007), and ventrolateral reticulospinal tract volumes (P = 0.017) to significantly predict worsening mJOA scores. Similarly, decreases in ventral reticulospinal tract volumes significantly predicted increasing Nurick scores (P = 0.039).

CONCLUSION

High-resolution 3T MRI can detect tract-specific volume loss in descending spinal cord tracts in CSM patients. Anterior/posterior spinal cord diameter, ventral reticulospinal tract, ventrolateral reticulospinal tract, lateral corticospinal tract, and rubrospinal tract volume loss are associated with CSM symptoms.

LEVEL OF EVIDENCE

2.

Clinico-Radiographic Discordance: An Evidence-Based Commentary on the Management of Degenerative Cervical Spinal Cord Compression in the Absence of Symptoms or With Only Mild Symptoms of Myelopathy

STUDY DESIGN

Narrative review with commentary.

OBJECTIVES

The growing use of magnetic resonance imaging (MRI) often leaves clinicians faced with scenarios where imaging findings are inconsistent with the clinical picture. This is particularly relevant for degenerative cervical spinal cord compression (CSCC). In this article, we provide a focused narrative literature review to address whether (1) surgery should be offered to asymptomatic patients with CSCC and (2) should MRI spinal cord signal changes influence clinical decisions for a patient with mild myelopathy from CSCC?

METHODS

Illustrative cases are presented with expert commentary which is supplemented by a focused literature review.

RESULTS

The literature suggests that CSCC from degenerative pathology is a common incidental radiographic finding. For those without symptoms of myelopathy, the short-term risk of progression is low. There is a lack of evidence to support surgery for asymptomatic individuals with CSCC who have no risk factors for progression. For these patients, the authors suggest non-operative management that includes education on the symptoms of myelopathy, clinical follow-up within 6 to 12 months, and avoidance of high-risk activities. Conversely, symptomatic patients have a notable risk of progression. Surgical intervention improves neurological function and quality of life regardless of severity. The authors support surgery as an option for all patients with mild myelopathy who are appropriate operative candidates. Intramedullary signal change on MRI has not been shown to reliably predict progression.

CONCLUSIONS

While MRI technologies are under evolution, we advise that surgical decisions for patients with CSCC should rely on clinical assessment and not imaging findings.

Application of Diffusion Tensor Imaging Cutoff Value to Evaluate the Severity and Postoperative Neurologic Recovery of Cervical Spondylotic Myelopathy

BACKGROUND

Magnetic resonance imaging (MRI) plays an important role in the assessment of spinal cord status for cervical spondylotic myelopathy (CSM). Diffusion tensor imaging (DTI) also is a novel investigation tool with good sensitivity to detect changes in CSM, but it is not routinely used in spinal cord evaluation.

METHODS

Sixty-six patients with CSM who required surgical decompression were included. All the patients were divided into 4 subgroups according to Japanese Orthopaedic Association (JOA) recovery rate. A 3.0T MR system was applied to obtain DTI of the spinal cord. Clinical assessment was performed with the JOA scores system.

RESULTS

DTI data of 61 patients were available for further analysis in this study. No significant differences in age, sex, cervical curvature, surgical approach, and preoperative JOA score between the 4 subgroups were found (P > 0.05). Significant differences in apparent diffusion coefficient (ADC) (P < 0.0001), mean diffusivity (MD), (P < 0.0001), axial diffusivity (AD) (P = 0.0459), and radial diffusivity (RD) (P < 0.0001) values were found between the 4 groups. The ADC (P < 0.0001), MD (P < 0.0001), AD (P = 0.0434), and RD (P < 0.0001) values were significantly correlated with JOA recovery rate. Cutoff values of ADC, MD, AD, and RD in this study were 1.378*10^-3, 1.378*10^-3, 2.386*10^-3, and 0.894*10^-3 mm²/s, respectively.

CONCLUSION

DTI was closely related to the severity of CSM, and cutoff values of DTI enabled the surgeons to predict the surgical outcomes in patients with CSM. These evaluation metrics may reflect the pathologic conditions of the spinal cord quantitatively, and potentially evaluate the functional status of spinal cords.

Comparison of the Prognostic Value of Different Quantitative Measurements of Increased Signal Intensity on T2-Weighted MRI in Cervical Spondylotic Myelopathy

OBJECTIVE

To investigate whether different quantitative measurements of increased signal intensity (ISI) on T2-weighted magnetic resonance imaging are useful for predicting surgical outcome in patients with cervical spondylotic myelopathy (CSM).

METHODS

We retrospectively reviewed 108 patients with ISI who underwent surgery for CSM. Clinical outcome was evaluated via the Japanese Orthopaedic Association (JOA) score and the recovery rate. Patients were divided into 2 groups based on the JOA recovery rate: good (≥50%) and fair (<50%). The quantitative measurements of ISI included the maximum vertical length and the signal change ratio (SCR). C2-C7 sagittal alignment, C2-C7 sagittal vertical axis, C2-C7 range of motion, maximum spinal cord compression, and maximum canal compromise also were assessed.

RESULTS

There were no significant differences in cervical sagittal alignment parameters between the groups. Multivariate analysis showed that a longer duration of symptoms, a lower preoperative JOA score, a longer preoperative ISI length, and a greater preoperative SCR were negatively associated with clinical outcomes. Receiver operating characteristic curve analysis showed that the best cutoff values of ISI length and SCR as negative predictors of surgical outcome were 15.50 mm and 1.56, respectively, and the areas under the receiver operating characteristic curve of preoperative ISI length, SCR that discriminate recovery rate of JOA score (≥50%, <50%) were 0.8507, 0.8422, respectively, and was 0.8903 for a combination of the 2.

CONCLUSIONS

Duration of symptoms, preoperative JOA score, preoperative ISI length, and SCR can reflect surgical outcome in patients with CSM; however, cervical sagittal alignment may not affect surgical outcome. Combining ISI length and SCR to depict ISI on T2-weighted magnetic resonance imaging is optimal and accurate. Patients with ISI length >15.50 mm and SCR >1.56 have fair surgical recovery.

Postoperative Resolution of Magnetic Resonance Imaging Signal Intensity Changes and the Associated Impact on Outcomes in Degenerative Cervical Myelopathy: Analysis of a Global Cohort of Patients

STUDY DESIGN

Subanalysis of the prospective AOSpine CSM North America and International studies.

OBJECTIVE

To describe the postoperative changes in magnetic resonance imaging (MRI) spinal cord signal intensity in degenerative cervical myelopathy (DCM) patients and to investigate the impact of its postoperative resolution on clinical outcomes.

SUMMARY OF BACKGROUND DATA

When examining the spinal cord, hyperintensity found in MRI T2-weighted images and hypointensity in T1-weighted images are known to correlate with preoperative severity of DCM and to predict postoperative neurological recovery. However, the clinical importance of these signal intensity changes in postoperative images has not been established.

METHODS

Among 757 surgical DCM patients enrolled in two prospective multicenter studies, postoperative MRI images obtained between 6 and 24 months after the operation were examined with a focus on T2 hyper- and T1 hypointensity in the spinal cord. The 2-year postoperative Nurick grade, modified Japanese Orthopaedic Association score and modified Japanese Orthopaedic Association recovery rate (RR) were analyzed between patients with or without resolution of signal intensity changes.

RESULTS

A total of 167 patients with preoperative T2 hyperintensity were included with complete postoperative MRI images. Of these patients, 11% showed resolution of signal intensity changes, 70% retained T2 hyperintensity only, and 19% showed both T2 hyper- and T1 hypointensity postoperatively. There was a stepwise trend toward worse postoperative outcomes, with the no signal intensity change group showing the best outcome and the T1 hypointensity group showing the worst (mean RR: 72% vs. 51% vs. 36%, P = 0.02). Patients who exhibited resolution of T2 hyperintensity showed better outcomes than those who retained it (RR: 72% vs. 47%, P = 0.04), but the resolution of T1 hypointensity was not associated with improved outcomes (RR: 38% vs. 26%, P = 0.36).

CONCLUSION

Postoperative resolution of T2 hyperintensity in patients with DCM was associated with the best clinical outcomes, whereas those with T1 hypointensity showed the worst.

LEVEL OF EVIDENCE

3.

Carotid Atherosclerosis and Cognitive Impairment in Nonstroke Patients

Objective:

As a vascular risk factor, carotid atherosclerosis is crucial to cognitive impairment. While carotid intima-media thickness, carotid artery plaque, and carotid stenosis can reflect carotid atherosclerosis in different stages, this review aimed to explore researches on the role of carotid intima-media thickness, carotid artery plaque, and carotid stenosis in the progress of cognitive impairment in nonstroke patients and tried to illustrate the possible mechanisms.

Data Sources:

We searched the PubMed database for recently published research articles up to July 2017, with the key words of “carotid atherosclerosis,” “carotid intima-media thickness,” “carotid plaque,” “carotid stenosis,” “nonstroke,” and “cognitive impairment.”

Study Selection:

Articles were obtained and reviewed to analyze the role of carotid atherosclerosis such as carotid intima-thickness, carotid plaque, and carotid stenosis in the progress of cognitive impairment in nonstroke patients and the possible mechanisms.

Results:

In recent years, most studies proved that by evaluating carotid atherosclerosis with ultrasonography, carotid atherosclerosis accounts for the development of cognitive decline in nonstroke patients. Carotid atherosclerosis not only impairs the subtle general cognitive function but also decreases the specific domains of cognitive function, such as memory, motor function, visual perception, attention, and executive function. But, it is still controversial. The possible mechanisms of cognitive impairment in nonstroke patients with carotid atherosclerosis can be classified as systemic global cerebrovascular function, small-vessel diseases, and the mixed lesions.

Conclusions:

Carotid atherosclerosis can be used to predict the risk of cognitive impairment. Furthermore, diagnosing and treating carotid atherosclerosis at early stage might help clinicians prevent and treat vascular cognitive impairment in nonstroke patients.

Can microstructural MRI detect subclinical tissue injury in subjects with asymptomatic cervical spinal cord compression? A prospective cohort study

OBJECTIVES

Degenerative cervical myelopathy (DCM) involves extrinsic spinal cord compression causing tissue injury and neurological dysfunction. Asymptomatic spinal cord compression (ASCC) is more common, but its significance is poorly defined. This study investigates if: (1) ASCC can be automatically diagnosed using spinal cord shape analysis; (2) multiparametric quantitative MRI can detect similar spinal cord tissue injury as previously observed in DCM.

DESIGN

Prospective observational longitudinal cohort study.

SETTING

Single centre, tertiary care and research institution.

PARTICIPANTS

40 neurologically intact subjects (19 female, 21 male) divided into groups with and without ASCC.

INTERVENTIONS

None.

OUTCOME MEASURES

Clinical assessments: modified Japanese Orthopaedic Association score and physical examination. 3T MRI assessments: automated morphometric analysis compared with consensus ratings of spinal cord compression, and measures of tissue injury: cross-sectional area, diffusion fractional anisotropy, magnetisation transfer ratio and T2*-weighted imaging white to grey matter signal intensity ratio (T2*WI WM/GM) extracted from rostral (C1-3), caudal (C6-7) and maximally compressed levels.

RESULTS

ASCC was present in 20/40 subjects. Diagnosis with automated shape analysis showed area under the curve >97%. Five MRI metrics showed differences suggestive of tissue injury in ASCC compared with uncompressed subjects (p<0.05), while a composite of all 10 measures (average of z scores) showed highly significant differences (p=0.002). At follow-up (median 21 months), two ASCC subjects developed DCM.

CONCLUSIONS

ASCC appears to be common and can be accurately and objectively diagnosed with automated morphometric analysis. Quantitative MRI appears to detect subclinical tissue injury in ASCC prior to the onset of neurological symptoms and signs. These findings require further validation, but offer the intriguing possibility of presymptomatic diagnosis and treatment of DCM and other spinal pathologies.

Image Diagnostic Classification of Magnetic Resonance T2 Increased Signal Intensity in Cervical Spondylotic Myelopathy: Clinical Evaluation Using Quantitative and Objective Assessment

STUDY DESIGN

A prospective imaging study.

OBJECTIVE

The study investigated whether the classification of increased signal intensity (ISI) using magnetic resonance imaging (MRI) reflects the severity of symptoms in patients with cervical spondylotic myelopathy (CSM).

SUMMARY OF BACKGROUND DATA

Although the ISI on MRI in patients with CSM is observed, the degree of ISI has not been examined. The association between ISI and the surgical outcomes in cervical myelopathy remains controversial.

METHODS

A total of 505 consecutive patients with CSM (311 males; 194 females) were enrolled. The mean age was 66.6 years (range, 41-91 yrs), with an average postoperative follow-up period of 26.5 ± 12.5 months. The ISI was classified into three groups based on sagittal T2-weighted MRI as follows: Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). Pre- and postoperative neurological status was evaluated using the Japanese Orthopedic Association scoring system for cervical myelopathy (JOA score) and quantifiable tests, including the 10-s grip and release test (10-s G&R test) and the 10-s step test.

RESULTS

The preoperative MRI showed 168 patients in Grade 0, 169 patients in Grade 1, and 168 in Grade 2, with no age differences among three groups. Grade 2 patients had a longer duration of symptom compared with the other grades. Grade 0 patients had a better postoperative JOA score and recovery rate compared with the other grades. The preoperative and postoperative scores in the G&R test and steps were better in the Grade 0 patients compared with the other grades. Grade 1 and 2 patients had similar outcomes and recovery rates.

CONCLUSION

ISI on MRI in patients with CSM was prospectively classified into three grades. The ISI grading was not associated with the preoperative severity of myelopathy and outcomes.

LEVEL OF EVIDENCE

2.

The Relationship Between MRI Signal Intensity Changes, Clinical Presentation, and Surgical Outcome in Degenerative Cervical Myelopathy: Analysis of a Global Cohort

STUDY DESIGN

Retrospective analysis of prospective data.

OBJECTIVE

To assess the relationship between MRI signal intensity changes, clinical presentation, and surgical outcome in degenerative cervical myelopathy (DCM).

SUMMARY OF BACKGROUND DATA

Several studies have sought to assess the extent of spinal cord dysfunction and the potential for postoperative neurological recovery through the evaluation of spinal cord signal change on T2-weighted (T2WI) and T1-weighted images (T1WI). There remains ambiguity if T2WI and T1WI signal changes (1) relate to baseline severity, and (2) predict neurological recovery after surgical treatment.

METHODS

Four hundred nineteen MRIs from two prospective multicenter studies were examined. Images were assessed for the presence, levels, and location of spinal cord signal intensity changes and compared with clinical data. Signal changes were also evaluated for the prediction of 2-year postoperative outcome using mJOA parameters.

RESULTS

MRIs were categorized by T1WI and T2WI signal change: no signal change (28.9%), T2WI hyperintensity-only (T2WI-only, 51.8%), and T2WI-hyperintensity and T1WI-hypointensity (T1WI+T2WI, 19.3%). T2WI-hyperintensity was present at multiple levels in 27% of patients overall. Baseline severity increased from no signal change to T2WI-only to T2WI+T1WI (P < 0.0001), and there was an incremental increase in the frequency of signs/symptoms. There were no differences in outcomes between no signal change and T2WI-only groups. The presence of T1WI-hypointensity correlated with reduced recovery ratio (P = 0.03) and likelihood of an optimal surgical outcome (P = 0.005), adjusting for baseline mJOA. A greater number of T2WI-hyperintensity levels was also associated with worse baseline severity (P < 0.0001) and recovery ratio (P = 0.001).

CONCLUSION

This analysis of a global cohort of DCM patients shows a stepwise trend toward increasing impairment from no signal change to T2WI-hypertensity to T1WI-hypointensity. T1WI signal change indicates more permanent injury, portending decreased functional recovery. T2WI-hyperintensity alone does not predict outcomes. Multiple levels of T2WI-hyperintensity suggest additional tissue injury, correlating with worse clinical impairment and recovery potential.

LEVEL OF EVIDENCE

2.

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.

MRI Analysis of the Combined Prospectively Collected AOSpine North America and International Data: The Prevalence and Spectrum of Pathologies in a Global Cohort of Patients With Degenerative Cervical Myelopathy

STUDY DESIGN

An ambispective analysis.

OBJECTIVE

The aim of this study was to report the global prevalence of specific degenerative cervical pathologies in patients with degenerative cervical myelopathy (DCM) through detailed review of magnetic resonance imaging (MRIs).

SUMMARY OF BACKGROUND DATA

DCM encompasses a spectrum of age-related conditions that result in progressive spinal cord injury.

METHODS

MRIs of 458 patients (age 56.4 ± 11.8, 285 male, 173 female) were reviewed for specific degenerative features, directionality of cord compression, levels of spinal cord compression, and signal changes on sagittal T2-weighted imaging (T2WI) and sagittal T1-weighted imaging (T1WI). Data were analyzed for differences between sex using Chi-square tests and geographic variations using Kruskal-Wallis tests.

RESULTS

Spondylosis was frequently present (89.7%) and was commonly accompanied by enlargement of the ligamentum flavum (LF) (59.9%). Single-level disc pathology, ossification of posterior longitudinal ligament (OPLL), and spondylolisthesis had a prevalence of ∼10% each. OPLL was accompanied by spondylosis in 91.7%. Klippel-Feil syndrome was observed in 2.0%. The Asia-Pacific region had more OPLL (29%, P = 3 × 10) and less spondylolisthesis (1.9%, P = 0.002). Females presented more commonly with single-level disc pathology (13.9% vs. 6.7%; P = 0.013), and males with spondylosis (92.3% vs. 85.6%; P = 0.02) and enlargement of LF (61.4% vs. 49.1%; P = 0.01). C5 to C6 was the most frequent maximum compressed site (39.5%) and region for T2WI hyperintensity (38.9%). T2WI hyperintensity more commonly presented in males (82.4% vs. 66.7%; P < 0.001).

CONCLUSION

This is the largest report on the prevalence and spectrum of pathology in patients with DCM. Herein, it has been demonstrated that degenerative features are highly interrelated, that females presented with milder MRI evidence of DCM, and that variations exist in the prevalence of pathologies between geographical regions.

LEVEL OF EVIDENCE

2.

Surgical Outcome of Laminoplasty for Cervical Spondylotic Myelopathy in an Elderly Population - Potentiality for Effective Early Surgical Intervention: A Meta-analysis

A systematic review and meta-analysis was conducted to determine differences in surgical outcomes of laminoplasty for cervical spondylotic myelopathy (CSM) between elderly and non-elderly patients. PubMed and Google Scholar searches were performed using several key words and phrases related to cervical laminoplasty in elderly populations. Included studies were written in English, addressed laminoplasty for cervical spondylotic myelopathy, and evaluated outcomes of the treatment. Statistical analysis was performed using a random-effect model. The heterogeneity of the studies was assessed using Cochran's Q statistic and I² statistic, and a funnel plot was constructed to evaluate publication bias. The search initially identified 255 articles on this topic. Nine clinical studies that met all inclusion criteria were included in the meta-analysis. A total of 1817 patients in these studies underwent cervical laminoplasty. Elderly patients had lower preoperative and postoperative Japanese Orthopedic Association (JOA) scores, and lower recovery rates based on JOA scores. Shorter operation times and reductions in intraoperative blood loss were found in the elderly group compared to the non-elderly group. The incidence of C5 palsy was not different between these groups. We here report the differences in surgical outcomes of laminoplasty for CSM through systematic review and meta-analysis. This report found poor surgical outcomes and lower preoperative JOA scores in elderly patients. Therefore, early surgical intervention may be recommended in elderly patients with CSM.

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

BACKGROUND AND PURPOSE

T2*-weighted imaging provides sharp contrast between spinal cord GM and WM, allowing their segmentation and cross-sectional area measurement. Injured WM demonstrates T2*WI hyperintensity but requires normalization for quantitative use. We introduce T2*WI WM/GM signal-intensity ratio and compare it against cross-sectional area, the DTI metric fractional anisotropy, and magnetization transfer ratio in degenerative cervical myelopathy.

MATERIALS AND METHODS

Fifty-eight patients with degenerative cervical myelopathy and 40 healthy subjects underwent 3T MR imaging, covering C1-C7. Metrics were automatically extracted at maximally compressed and uncompressed rostral/caudal levels. Normalized metrics were compared with t tests, area under the curve, and logistic regression. Relationships with clinical measures were analyzed by using Pearson correlation and multiple linear regression.

RESULTS

The maximally compressed level cross-sectional area demonstrated superior differences (P = 1 × 10^-13), diagnostic accuracy (area under the curve = 0.890), and univariate correlation with the modified Japanese Orthopedic Association score (0.66). T2*WI WM/GM showed strong differences (rostral: P = 8 × 10^-7; maximally compressed level: P = 1 × 10^-11; caudal: P = 1 × 10^-4), correlations (modified Japanese Orthopedic Association score; rostral: -0.52; maximally compressed level: -0.59; caudal: -0.36), and diagnostic accuracy (rostral: 0.775; maximally compressed level: 0.860; caudal: 0.721), outperforming fractional anisotropy and magnetization transfer ratio in most comparisons and cross-sectional area at rostral/caudal levels. Rostral T2*WI WM/GM showed the strongest correlations with focal motor (-0.45) and sensory (-0.49) deficits and was the strongest independent predictor of the modified Japanese Orthopedic Association score (P = .01) and diagnosis (P = .02) in multivariate models (R² = 0.59, P = 8 × 10^-13; area under the curve = 0.954, respectively).

CONCLUSIONS

T2*WI WM/GM shows promise as a novel biomarker of WM injury. It detects damage in compressed and uncompressed regions and contributes substantially to multivariate models for diagnosis and correlation with impairment. Our multiparametric approach overcomes limitations of individual measures, having the potential to improve diagnostics, monitor progression, and predict outcomes.

Axial MR diffusion tensor imaging and tractography in clinical diagnosed and pathology confirmed cervical spinal cord astrocytoma

OBJECTIVE

To evaluate the diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) features of cervical spinal cord astrocytoma.

METHODS

Eleven patients with cervical spinal cord astrocytomas and 10 healthy volunteers were recruited in this study. Conventional magnetic resonance imaging (MRI) and axial DTI were performed on a 3.0T MRI system. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values for the lesions were measured. DTT was performed using the principal diffusion direction method.

RESULTS

ADC values of the lesions and the normal-appearing tissue around the tumour (NATAT) on T2-weighted imaging (T2WI) increased. The ADC values of the lesions were higher. The FA values of the lesions and the NATAT decreased significantly, with the lesions having lower FA values. The RD value (1.36±0.49) of the tumours was significantly higher than those found in the healthy controls, but similar for the AD value (1.84±0.56). There were no differences in ADC or FA values between lesions and NATAT in McCormick Type I vs. Type II patients. Based on the DTT, 7 patients with solid mass tumours were classified as Type I. One patient with a solid mass, 2 patients with cystic degeneration inside the lesions, and 1 patient with a cyst around the mass were classified as Type II.

CONCLUSIONS

FA values of the cervical spinal cord astrocytoma decreased, but the ADC values increased. DTI was sensitive for the evaluation of pathological changes that could not be visualized on T2WI. Our preliminary study indicates that DTT can be used to guide operation planning, and that axial images of DTT may be more valuable.

Cervical compressive myelopathy: flow analysis of cerebrospinal fluid using phase-contrast magnetic resonance imaging

PURPOSE

To evaluate cerebrospinal fluid (CSF) flow in cervical compressive myelopathy (CCM), by both quantitative and qualitative analyses, using 3T cine phase-contrast magnetic resonance imaging (cine MRI).

METHODS

From September, 2014 to June, 2015, we enrolled 45 subjects (18 women and 27 men, mean age, 61.7 ± 13.4 years) to undergo cervical cine MRI. The subjects were divided into three groups: no stenosis and cervical stenosis with and without intramedullary T2 hyperintensity. We measured maximal CSF velocity, and 12 CSF velocity waveforms were plotted per subject. Two readers independently assessed the CSF waveform shape (0 absent; 1 serrated; 2 bi-directional with small amplitude; and 3 normal bi-directional waveform) and the CSF motion pattern (0 absent; 1 interrupted; and 2 intact). The numbers of 12 waveform shapes were summed to yield a CSF waveform score. Linear mixed model and ROC curve analyses were used for statistical analyses.

RESULTS

Maximal CSF velocity was significantly lower in CCM (marginal mean, 2.72 cm/s) than in stenosis without intramedullary T2 hyperintensity (3.27 cm/s, p = 0.027) and no stenosis (3.80 cm/s, p < 0.001). Bi-phasic CSF motion was lost in cervical stenosis. CSF waveform scores of 17 (area under curve (AUC), 0.797; p = 0.003) and 16.5 (AUC, 0.790; p = 0.004) could predict Japanese Orthopedic Association (JOA) score corresponding to CCM.

CONCLUSIONS

Maximal CSF velocity and CSF waveform score on cine MRI decreased in CCM and was correlated with the JOA score. Thus, both quantitative and qualitative analyses using cine MRI could effectively demonstrate CSF flow alterations in CCM.