Quantifying neurodegeneration of the cervical cord and brain in degenerative cervical myelopathy: A multicentre study using quantitative magnetic resonance imaging.

BACKGROUND AND PURPOSE: Simultaneous assessment of neurodegeneration in both the cervical cord and brain across multiple centres can enhance the effectiveness of clinical trials. Thus, this study aims to simultaneously assess microstructural changes in the cervical cord and brain above the stenosis in degenerative cervical myelopathy (DCM) using quantitative magnetic resonance imaging (MRI) in a multicentre study. METHODS: We applied voxelwise analysis with a probabilistic brain/spinal cord template embedded in statistical parametric mappin (SPM-BSC) to process multi parametric mapping (MPM) including effective transverse relaxation rate (R2*), longitudinal relaxation rate (R1), and magnetization transfer (MT), which are indirectly sensitive to iron and myelin content. Regression analysis was conducted to establish associations between neurodegeneration and clinical impairment. Thirty-eight DCM patients (mean age ± SD = 58.45 ± 11.47 years) and 38 healthy controls (mean age ± SD = 41.18 ± 12.75 years) were recruited at University Hospital Balgrist, Switzerland and Toronto Western Hospital, Canada. RESULTS: Remote atrophy was observed in the cervical cord (p = 0.002) and in the left thalamus (0.026) of the DCM group. R1 was decreased in the periaqueductal grey matter (p = 0.014), thalamus (p = 0.001), corpus callosum (p = 0.0001), and cranial corticospinal tract (p = 0.03). R2* was increased in the primary somatosensory cortices (p = 0.008). Sensory impairments were associated with increased iron-sensitive R2* in the thalamus and periaqueductal grey matter in DCM. CONCLUSIONS: Simultaneous assessment of the spinal cord and brain revealed DCM-induced demyelination, iron deposition, and atrophy. The extent of remote neurodegeneration was associated with sensory impairment, highlighting the intricate and expansive nature of microstructural neurodegeneration in DCM, reaching beyond the stenosis level.

Focal compression of the cervical spinal cord alone does not indicate high risk of neurological deterioration in patients with a diagnosis of mild degenerative cervical myelopathy.

Degenerative Cervical Myelopathy (DCM) is the functional derangement of the spinal cord resulting from vertebral column spondylotic degeneration. Typical neurological symptoms of DCM include gait imbalance, hand/arm numbness, and upper extremity dexterity loss. Greater spinal cord compression is believed to lead to a higher rate of neurological deterioration, although clinical experience suggests a more complex mechanism involving spinal canal diameter (SCD). In this study, we utilized machine learning clustering to understand the relationship between SCD and different patterns of cord compression (i.e. compression at one disc level, two disc levels, etc.) to identify patient groups at risk of neurological deterioration. 124 MRI scans from 51 non-operative DCM patients were assessed through manual scoring of cord compression and SCD measurements. Dimensionality reduction techniques and k-means clustering established patient groups that were then defined with their unique risk criteria. We found that the compression pattern is unimportant at SCD extremes (≤14.5 mm or > 15.75 mm). Otherwise, severe spinal cord compression at two disc levels increases deterioration likelihood. Notably, if SCD is normal and cord compression is not severe at multiple levels, deterioration likelihood is relatively reduced, even if the spinal cord is experiencing compression. We elucidated five patient groups with their associated risks of deterioration, according to both SCD range and cord compression pattern. Overall, SCD and focal cord compression alone do not reliably predict an increased risk of neurological deterioration. Instead, the specific combination of narrow SCD with multi-level focal cord compression increases the likelihood of neurological deterioration in mild DCM patients.

Malignant melanotic schwannoma of the cervical spinal cord: a case report.

Spinal cord malignant melanotic schwannoma (MMNST) is a rare central nervous system tumor that originates from the spinal cord or spinal myelin sheath cells and can produce melanin. This type of tumor is usually highly aggressive and malignant, with a poor prognosis. The clinical manifestations of spinal cord MMNST are mainly pain, paresthesia, muscle weakness, muscle atrophy, etc., and symptoms of spinal cord compression, such as intestinal and bladder dysfunction, paraplegia, etc. Early detection of tumor lesions can facilitate tumor removal, improve patients' quality of life, and prolong patients' survival. In this case report, a 27-year-old young woman was diagnosed with MMNST of the cervical spinal cord due to weakness of her limbs in our hospital, and underwent surgical resection. The patient's limbs returned to normal after surgery. It is worth mentioning that the patient visited our hospital 7 months ago for "right upper limb pain for 3 days" and was diagnosed with a cervical spine space-occupying lesion at the same position this time, but the pathology report was "hemosiderosis". The patient's limbs returned to normal after surgery. It is worth mentioning that the patient visited our hospital 7 months ago for "right upper limb pain for 3 days" and was diagnosed with a cervical spine space-occupying lesion at the same position this time, but the pathology report was "hemosiderosis". This case report aims to raise awareness of the problem of spinal cord MMNST and contribute to greater knowledge of this rare tumor. This case report aims to raise awareness of the problem of spinal cord MMNST and contribute to greater knowledge of this rare tumor.

Strategies and safety simulations for ultrasonic cervical spinal cord neuromodulation.

Objective. Focused ultrasound spinal cord neuromodulation has been demonstrated in small animals. However, most of the tested neuromodulatory exposures are similar in intensity and exposure duration to the reported small animal threshold for possible spinal cord damage. All efforts must be made to minimize the risk and assure the safety of potential human studies, while maximizing potential treatment efficacy. This requires an understanding of ultrasound propagation and heat deposition within the human spine.Approach. Combined acoustic and thermal modelling was used to assess the pressure and heat distributions produced by a 500 kHz source focused to the C5/C6 level via two approaches (a) the posterior acoustic window between vertebral posterior arches, and (b) the lateral intervertebral foramen from which the C6 spinal nerve exits. Pulse trains of fifty 0.1 s pulses (pulse repetition frequency: 0.33 Hz, free-field spatial peak pulse-averaged intensity: 10 W cm-2) were simulated for four subjects and for ±10 mm translational and ±10∘rotational source positioning errors.Main results.Target pressures ranged between 20%-70% of free-field spatial peak pressures with the posterior approach, and 20%-100% with the lateral approach. When the posterior source was optimally positioned, peak spine heating values were below 1 ∘C, but source mispositioning resulted in bone heating up to 4 ∘C. Heating with the lateral approach did not exceed 2 ∘C within the mispositioning range. There were substantial inter-subject differences in target pressures and peak heating values. Target pressure varied three to four-fold between subjects, depending on approach, while peak heating varied approximately two-fold between subjects. This results in a nearly ten-fold range between subjects in the target pressure achieved per degree of maximum heating.Significance. This study highlights the utility of trans-spine ultrasound simulation software and need for precise source-anatomy positioning to assure the subject-specific safety and efficacy of focused ultrasound spinal cord therapies.

[A case of high cervical cord infarction presenting with cardiopulmonary arrest due to respiratory dysfunction].

A 46-year-old man with neck pain and impaired physical mobility called for emergency medical services. The patient was able to communicate with the emergency medical team upon their arrival. However, he went into cardiopulmonary arrest 5 minutes later. Cardiopulmonary resuscitation was immediately performed, and the patient was admitted to our hospital with a Glasgow Coma Scale score of E1V1M1. His respiratory rate was 5 breaths/minute and his partial pressure of carbon dioxide in arterial blood (PaCO2) was 127 |mmHg, necessitating intubation and ventilation. His consciousness improved as the PaCO2 level decreased. However, he was unable to be weaned off the ventilator and breathe independently. Neurological examination revealed flaccid quadriplegia, pain sensation up to the C5 level, absence of deep tendon reflexes, indifferent plantar responses, and absence of the rectoanal inhibitory reflex. Magnetic resonance imaging showed a hyperintense lesion with slight enlargement of the anterior two-thirds of the spinal cord at the C2-C4 level on both T2-weighted and diffusion-weighted images, consistent with a diagnosis of spinal cord infarction. Although the quadriplegia and sensory loss partially improved, the patient was unable to be weaned from the ventilator. Cervical cord infarction of the anterior spinal artery can cause rapid respiratory failure leading to cardiopulmonary arrest. Therefore, cervical cord infarction should be included as a differential diagnosis when examining patients after cardiopulmonary resuscitation.

Mirror movements associated with cervical limited dorsal myeloschisis: a unique case study.

Mirror movements, characterized by involuntary symmetrical movements in contralateral body parts during intentional movements, have been associated with various neurological conditions. Limited dorsal myeloschisis (LDM), a rare form of spinal dysraphism, is defined by a focal closed midline defect and a fibro-neural stalk connecting the skin lesion to the underlying cord. We present a unique case of a 4-year-old girl with cervical LDM exhibiting mirror movements. The patient underwent surgical exploration, skin tag excision, fibrous tract removal, and cervical spinal cord detethering. Post-operatively, there was a partial improvement in mirror movements and a complete resolution of hand grip weakness.

Evaluation of the structural integrity of different spinal cord tracts with magnetization transfer ratio in degenerative cervical myelopathy.

PURPOSE: Degenerative cervical myelopathy (DCM) is a common cause of spinal cord dysfunction. In this study, we explored the potential of magnetization transfer ratio (MTR) for evaluating the structural integrity of spinal cord tracts in patients with clinically significant DCM. METHODS: Fifty-three patients with DCM and 41 patients with cervical radiculopathy were evaluated using high-resolution cervical spinal cord magnetic resonance imaging (MRI), which included the magnetization transfer technique. MRI data were analyzed with the Spinal Cord Toolbox (v5.5); MTR values in each spinal tract were calculated and compared between groups after correction for patient age and sex. Correlations between MTR values and patients' clinical disability rate were also evaluated. RESULTS: A statistically significant reduction in the average MTR of the spinal cord white matter, as well as the MTR of the ventral columns and lateral funiculi, was revealed in the DCM group (adjusted p < 0.01 for all comparisons). Furthermore, reductions in MTR values in the fasciculus cuneatus, spinocerebellar, rubrospinal, and reticulospinal tracts were found in patients with DCM (adjusted p < 0.01 for all comparisons). Positive correlations between the JOA score and the MTR within the ventral columns of the spinal cord (R = 0.38, adjusted p < 0.05) and the ventral spinocerebellar tract (R = 0.41, adjusted p < 0.05) were revealed. CONCLUSION: The findings of our study indicate that demyelination in patients with DCM primarily affects the spinal tracts of the extrapyramidal system, and the extent of these changes is related to the severity of the condition.

Cervical and thoracic spinal cord gray matter atrophy is associated with disability in patients with amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: In amyotrophic lateral sclerosis (ALS), there is an unmet need for more precise patient characterization through quantitative, ideally operator-independent, assessments of disease extent and severity. Radially sampled averaged magnetization inversion recovery acquisitions (rAMIRA) magnetic resonance imaging enables gray matter (GM) and white matter (WM) area quantitation in the cervical and thoracic spinal cord (SC) with optimized contrast. We aimed to investigate rAMIRA-derived SC GM and SC WM areas and their association with clinical phenotype and disability in ALS. METHODS: A total of 36 patients with ALS (mean [SD] age 61.7 [12.6] years, 14 women) and 36 healthy, age- and sex-matched controls (HCs; mean [SD] age 63.1 [12.1] years, 14 women) underwent two-dimensional axial rAMIRA imaging at the inter-vertebral disc levels C2/3-C5/C6 and the lumbar enlargement level Tmax. ALS Functional Rating Scale-revised (ALSFRS-R) score, muscle strength, and sniff nasal inspiratory pressure (SNIP) were assessed. RESULTS: Compared to HCs, GM and WM areas were reduced in patients at all cervical levels (p < 0.0001). GM area (p = 0.0001), but not WM area, was reduced at Tmax. Patients with King's Stage 3 showed significant GM atrophy at all levels, while patients with King's Stage 1 showed significant GM atrophy selectively at Tmax. SC GM area was significantly associated with muscle force at corresponding myotomes. GM area at C3/C4 was associated with ALSFRS-R (p < 0.001) and SNIP (p = 0.0016). CONCLUSION: Patients with ALS assessed by rAMIRA imaging show significant cervical and thoracic SC GM and SC WM atrophy. SC GM area correlates with muscle strength and clinical disability. GM area reduction at Tmax may be an early disease sign. Longitudinal studies are warranted.

Diffusion tensor imaging within the healthy cervical spinal cord: Within- participants reliability and measurement error.

BACKGROUND: Diffusion tensor imaging (DTI) is a promising technique for the visualization of the cervical spinal cord (CSC) in vivo. It provides information about the tissue structure of axonal white matter, and it is thought to be more sensitive than other MR imaging techniques for the evaluation of damage to tracts in the spinal cord. AIM: The purpose of this study was to determine the within-participants reliability and error magnitude of measurements of DTI metrics in healthy human CSC. METHODS: A total of twenty healthy controls (10 male, mean age: 33.9 ± 3.5 years, 10 females, mean age: 47.5 ± 14.4 years), with no family history of any neurological disorders or a contraindication to MRI scanning were recruited over a period of two months. Each participant was scanned twice with an MRI 3 T scanner using standard DTI sequences. Spinal Cord Toolbox (SCT) software was used for image post-processing. Data were first corrected for motion artefact, then segmented, registered to a template, and then the DTI metrics were computed. The within-participants coefficients of variation (CV%), the single and average within-participants intraclass correlation coefficients (ICC) and Bland-Altman plots for WM, VC, DC and LC fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were determined for the cervical spinal cord (between the 2nd and 5th cervical vertebrae). RESULTS: DTI metrics showed poor to excellent within-participants reliability for both single and average ICC and moderate to high reproducibility for CV%, all variation dependent on the location of the ROI. The BA plots showed good within-participants agreement between the scan-rescan values. CONCLUSION: Results from this reliability study demonstrate that clinical trials using the DTI technique are feasible and that DTI, in particular regions of the cord is suitable for use for the monitoring of degenerative WM changes.

Thermal stimulus task fMRI in the cervical spinal cord at 7 Tesla.

Although functional magnetic resonance imaging (fMRI) is widely applied in the brain, fMRI of the spinal cord is more technically demanding. Proximity to the vertebral column and lungs results in strong spatial inhomogeneity and temporal fluctuations in B0 . Increasing field strength enables higher spatial resolution and improved sensitivity to blood oxygenation level-dependent (BOLD) signal, but amplifies the effects of B0 inhomogeneity. In this work, we present the first task fMRI in the spinal cord at 7 T. Further, we compare the performance of single-shot and multi-shot 2D echo-planar imaging (EPI) protocols, which differ in sensitivity to spatial and temporal B0 inhomogeneity. The cervical spinal cords of 11 healthy volunteers were scanned at 7 T using single-shot 2D EPI at 0.75 mm in-plane resolution and multi-shot 2D EPI at 0.75 and 0.6 mm in-plane resolutions. All protocols used 3 mm slice thickness. For each protocol, the BOLD response to 13 10-s noxious thermal stimuli applied to the right thumb was acquired in a 10-min fMRI run. Image quality, temporal signal to noise ratio (SNR), and BOLD activation (percent signal change and z-stat) at both individual- and group-level were evaluated between the protocols. Temporal SNR was highest in single-shot and multi-shot 0.75 mm protocols. In group-level analyses, activation clusters appeared in all protocols in the ipsilateral dorsal quadrant at the expected C6 neurological level. In individual-level analyses, activation clusters at the expected level were detected in some, but not all subjects and protocols. Single-shot 0.75 mm generally produced the highest mean z-statistic, while multi-shot 0.60 mm produced the best-localized activation clusters and the least geometric distortion. Larger than expected within-subject segmental variation of BOLD activation along the cord was observed. Group-level sensory task fMRI of the cervical spinal cord is feasible at 7 T with single-shot or multi-shot EPI. The best choice of protocol will likely depend on the relative importance of sensitivity to activation versus spatial localization of activation for a given experiment. PRACTITIONER POINTS: First stimulus task fMRI results in the spinal cord at 7 T. Single-shot 0.75 mm 2D EPI produced the highest mean z-statistic. Multi-shot 0.60 mm 2D EPI provided the best-localized activation and least distortion.

Spinal fMRI demonstrates segmental organisation of functionally connected networks in the cervical spinal cord: A test-retest reliability study.

Resting functional magnetic resonance imaging (fMRI) studies have identified intrinsic spinal cord activity, which forms organised motor (ventral) and sensory (dorsal) resting-state networks. However, to facilitate the use of spinal fMRI in, for example, clinical studies, it is crucial to first assess the reliability of the method, particularly given the unique anatomical, physiological, and methodological challenges associated with acquiring the data. Here, we characterise functional connectivity relationships in the cervical cord and assess their between-session test-retest reliability in 23 young healthy volunteers. Resting-state networks were estimated in two ways (1) by estimating seed-to-voxel connectivity maps and (2) by calculating seed-to-seed correlations. Seed regions corresponded to the four grey matter horns (ventral/dorsal and left/right) of C5-C8 segmental levels. Test-retest reliability was assessed using the intraclass correlation coefficient. Spatial overlap of clusters derived from seed-to-voxel analysis between sessions was examined using Dice coefficients. Following seed-to-voxel analysis, we observed distinct unilateral dorsal and ventral organisation of cervical spinal resting-state networks that was largely confined in the rostro-caudal extent to each spinal segmental level, with more sparse connections observed between segments. Additionally, strongest correlations were observed between within-segment ipsilateral dorsal-ventral connections, followed by within-segment dorso-dorsal and ventro-ventral connections. Test-retest reliability of these networks was mixed. Reliability was poor when assessed on a voxelwise level, with more promising indications of reliability when examining the average signal within clusters. Reliability of correlation strength between seeds was highly variable, with the highest reliability achieved in ipsilateral dorsal-ventral and dorso-dorsal/ventro-ventral connectivity. However, the spatial overlap of networks between sessions was excellent. We demonstrate that while test-retest reliability of cervical spinal resting-state networks is mixed, their spatial extent is similar across sessions, suggesting that these networks are characterised by a consistent spatial representation over time.

Cervical spinal cord angiography and vessel-selective perfusion imaging in the rat.

Arterial spin labeling (ASL) has been widely used to evaluate arterial blood and perfusion dynamics, particularly in the brain, but its application to the spinal cord has been limited. The purpose of this study was to optimize vessel-selective pseudocontinuous arterial spin labeling (pCASL) for angiographic and perfusion imaging of the rat cervical spinal cord. A pCASL preparation module was combined with a train of gradient echoes for dynamic angiography. The effects of the echo train flip angle, label duration, and a Cartesian or radial readout were compared to examine their effects on visualizing the segmental arteries and anterior spinal artery (ASA) that supply the spinal cord. Lastly, vessel-selective encoding with either vessel-encoded pCASL (VE-pCASL) or super-selective pCASL (SS-pCASL) were compared. Vascular territory maps were obtained with VE-pCASL perfusion imaging of the spinal cord, and the interanimal variability was evaluated. The results demonstrated that longer label durations (200 ms) resulted in greater signal-to-noise ratio in the vertebral arteries, improved the conspicuity of the ASA, and produced better quality maps of blood arrival times. Cartesian and radial readouts demonstrated similar image quality. Both VE-pCASL and SS-pCASL adequately labeled the right or left vertebral arteries, which revealed the interanimal variability in the segmental artery with variations in their location, number, and laterality. VE-pCASL also demonstrated unique interanimal variations in spinal cord perfusion with a right-sided dominance across the six animals. Vessel-selective pCASL successfully achieved visualization of the arterial inflow dynamics and corresponding perfusion territories of the spinal cord. These methodological developments provide unique insights into the interanimal variations in the arterial anatomy and dynamics of spinal cord perfusion.

Limited utility of adding 3T cervical spinal cord MRI to monitor disease activity in multiple sclerosis.

BACKGROUND: Performing routine brain magnetic resonance imaging (MRI) is widely accepted as the standard of care for disease monitoring in multiple sclerosis (MS), but the utility of performing routine spinal cord (SC) MRI for this purpose is still debatable. OBJECTIVE: This study aimed to measure the frequency of new isolated cervical spinal cord lesions (CSLs) in people with MS (pwMS) undergoing routine brain and cervical SC-MRI for disease monitoring and determine the factors associated with the development of new CSLs and their prognostic value. METHODS: We retrospectively identified 1576 pwMS who underwent follow-up 3T brain and cervical SC-MRI over a 9-month period. MRI was reviewed for the presence of new brain lesions (BLs) and CSLs. Clinical records were reviewed for interval relapses between sequential scans and subsequent clinical relapse and disability worsening after the follow-up MRI. RESULTS: In 1285 pwMS (median interval: 13-14 months) who were clinically stable with respect to relapses, 73 (5.7%) had new CSLs, of which 49 (3.8%) had concomitant new BLs and 24 (1.9%) had new isolated CSLs only. New asymptomatic CSLs were associated with ⩾ 3 prior relapses (p = 0.04), no disease-modifying therapy (DMT) use (p = 0.048), and ⩾ 3 new BLs (p < 0.001); ⩾ 3 new BLs (OR: 7.11, 95% CI: 4.3-11.7, p < 0.001) remained independently associated with new CSLs on multivariable analysis. Having new asymptomatic CSLs was not independently associated with subsequent relapse or disability worsening after the follow-up MRI (median follow-up time of 26 months). CONCLUSION: Routine brain and cervical SC-MRI detected new isolated CSLs in only < 2% of clinically stable pwMS. Developing new asymptomatic CSLs was associated with concomitant new BLs and did not confer an independent increased risk of relapse or disability worsening. Performing SC-MRI may not be warranted for routine monitoring in most pwMS, and performing only brain MRI may be sufficient to capture the vast majority of clinically silent disease activity.

Association of Mean Upper Cervical Spinal Cord Cross-Sectional Area With Cerebral Small Vessel Disease: A Community-Based Cohort Study.

BACKGROUND: The purpose of this study was to investigate the association between the mean upper cervical spinal cord cross-sectional area (MUCCA) and the risk and severity of cerebral small vessel disease (CSVD). METHODS: Community-dwelling residents in Lishui City, China, from the cross-sectional survey in the PRECISE cohort study (Polyvascular Evaluation for Cognitive Impairment and Vascular Events) conducted from 2017 to 2019. We included 1644 of 3067 community-dwelling adults in the PRECISE study after excluding those with incorrect, incomplete, insufficient, or missing clinical or imaging data. Total and modified total CSVD scores, as well as magnetic resonance imaging features, including white matter hyperintensity, lacunes, cerebral microbleeds, enlarged perivascular spaces, and brain atrophy, were assessed at the baseline. The Spinal Cord Toolbox was used to measure the upper cervical spinal cord cross-sectional area of the C1 to C3 segments of the spinal cord and its average value was taken as MUCCA. Participants were divided into 4 groups according to quartiles of MUCCA. Associations were analyzed using linear regression models adjusted for age, sex, current smoking and drinking, medical history, intracranial volume, and total cortical volume. RESULTS: The means±SD age of the participants was 61.4±6.5 years, and 635 of 1644 participants (38.6%) were men. The MUCCA was smaller in patients with CSVD than those without CSVD. Using the total CSVD score as a criterion, the MUCCA was 61.78±6.12 cm2 in 504 of 1644 participants with CSVD and 62.74±5.94 cm2 in 1140 of 1644 participants without CSVD. Using the modified total CSVD score, the MUCCA was 61.81±6.04 cm2 in 699 of 1644 participants with CSVD and 62.91±5.94 cm2 in 945 of 1644 without CSVD. There were statistical differences between the 2 groups after adjusting for covariates in 3 models. The MUCCA was negatively associated with the total and modified total CSVD scores (adjusted ß value, -0.009 [95% CI, -0.01 to -0.003] and -0.007 [95% CI, -0.01 to -0.0006]) after adjustment for covariates. Furthermore, the MUCCA was negatively associated with the white matter hyperintensity burden (adjusted ß value, -0.01 [95% CI, -0.02 to -0.003]), enlarged perivascular spaces in the basal ganglia (adjusted ß value, -0.005 [95% CI, -0.009 to -0.001]), lacunes (adjusted ß value, -0.004 [95% CI, -0.007 to -0.0007]), and brain atrophy (adjusted ß value, -0.009 [95% CI, -0.01 to -0.004]). CONCLUSIONS: The MUCCA and CSVD were correlated. Spinal cord atrophy may serve as an imaging marker for CSVD; thus, small vessel disease may involve the spinal cord in addition to being intracranial.

Reproducibility of 3D pH-weighted chemical exchange saturation transfer contrast in the healthy cervical spinal cord.

Spinal cord ischemia and hypoxia can be caused by compression, injury, and vascular alterations. Measuring ischemia and hypoxia directly in the spinal cord noninvasively remains challenging. Ischemia and hypoxia alter tissue pH, providing a physiologic parameter that may be more directly related to tissue viability. Chemical exchange saturation transfer (CEST) is an MRI contrast mechanism that can be made sensitive to pH. More specifically, amine/amide concentration independent detection (AACID) is a recently developed endogenous CEST contrast that has demonstrated sensitivity to intracellular pH at 9.4 T. The goal of this study was to evaluate the reproducibility of AACID CEST measurements at different levels of the healthy cervical spinal cord at 3.0 T incorporating B1 correction. Using a 3.0 T MRI scanner, two 3D CEST scans (saturation pulse train followed by a 3D snapshot gradient-echo readout) were performed on 12 healthy subjects approximately 10 days apart, with the CEST volume centered at the C4 level for all subjects. Scan-rescan reproducibility was evaluated by examining between and within-subject coefficients of variation (CVs) and absolute AACID value differences. The C4 level of the spinal cord demonstrated the lowest within-subject CVs (4.1%-4.3%), between-subject CVs (5.6%-6.3%), and absolute AACID percent difference (5.8-6.1%). The B1 correction scheme significantly improved reproducibility (adjusted p-value = 0.002) compared with the noncorrected data, suggesting that implementing B1 corrections in the spinal cord is beneficial. It was concluded that pH-weighted AACID measurements, incorporating B1-inhomogeneity correction, were reproducible within subjects along the healthy cervical spinal cord and that optimal image quality was achieved at the center of the 3D CEST volume.

Wallerian Degeneration Assessed by Multi-Modal Magnetic Resonance Imaging of Cervical Spinal Cord Is Associated With Neurological Impairment After Spinal Cord Injury.

While Wallerian degeneration (WD) is a crucial pathological process induced with spinal cord injury (SCI), its underlying mechanisms is still understudied. In this study, we aim to assess structural alterations and clinical significance of WD in the cervical cord following SCI using multi-modal magnetic resonance imaging (MRI), which combines T2*-weighted imaging and diffusion tensor imaging (DTI). T2*-weighted images allow segmentation of anatomical structures and the detection of WD on macrostructural level. DTI, on the other hand, can identify the reduction in neuroaxonal integrity by measuring the diffusion of water molecules on the microstructural level. In this prospective study, 35 SCI patients (19 paraplegic and 16 tetraplegic patients) and 12 healthy controls were recruited between July 2020 and May 2022. The hyperintensity voxels in the dorsal column was manually labeled as WD on T2*-weighted images. The mean cross-sectional area (CSA) and mean DTI indexes of WD at the C2 level were calculated and compared between groups. Correlation analysis was used to determine the associations of the magnitude of WD with lesion characteristics and clinical outcomes. Compared with controls, SCI patients showed evident hyperintensity (35/35) and decreased neuroaxonal integrity (p < 0.05) within the dorsal column at the C2 level. A higher neurological level of injury was associated with a larger mean CSA and reduction in neuroaxonal integrity within WD (p < 0.05). Smaller total and dorsal tissue bridges were related to greater mean CSA and lower fractional anisotropy values in WD (p < 0.05), respectively. Moreover, SCI participants with significantly larger CSAs and significantly lower microstructural integrity had worse sensory outcomes (p < 0.05). This comprehensive evaluation of WD can help us better understand the mechanisms of WD, monitor progression, and assess the effectiveness of therapeutic interventions after SCI.

Predictive value of intraoperative contrast-enhanced ultrasound in functional recovery of non-traumatic cervical spinal cord injury.

OBJECTIVES: To evaluate the ability of intraoperative CEUS to predict neurological recovery in patients with degenerative cervical myelopathy (DCM). METHODS: Twenty-six patients with DCM who underwent laminoplasty and intraoperative ultrasound (IOUS) were included in this prospective study. The modified Japanese Orthopaedic Association (mJOA) scores and MRI were assessed before surgery and 12 months postoperatively. The anteroposterior diameter (APD), maximum spinal cord compression (MSCC), and area of signal changes in the cord at the compressed and normal levels were measured and compared using MRI and IOUS. Conventional blood flow and CEUS indices (time to peak, ascending slope, peak intensity (PI), and area under the curve (AUC)) at different levels during IOUS were calculated and analysed. Correlations between all indicators and the neurological recovery rate were evaluated. RESULTS: All patients underwent IOUS and intraoperative CEUS, and the total recovery rate was 50.7 ± 33.3%. APD and MSCC improved significantly (p < 0.01). The recovery rate of the hyperechoic lesion group was significantly worse than that of the isoechoic group (p = 0.016). 22 patients were analysed by contrast analysis software. PI was higher in the compressed zone than in the normal zone (24.58 ± 3.19 versus 22.43 ± 2.39, p = 0.019). ΔPI compress-normal and ΔAUC compress-normal of the hyperechoic lesion group were significantly higher than those of the isoechoic group (median 2.19 versus 0.55, p = 0.017; 135.7 versus 21.54, p = 0.014, respectively), and both indices were moderately negatively correlated with the recovery rate (r = - 0.463, p = 0.030; r = - 0.466, p = 0.029). CONCLUSIONS: Signal changes and microvascular perfusion evaluated using CEUS during surgery are valuable predictors of cervical myelopathy prognosis. CLINICAL RELEVANCE STATEMENT: In the spinal cord compression area of degenerative cervical myelopathy, especially in the hyperechoic lesions, intraoperative CEUS showed more significant contrast agent perfusion than in the normal area, and the degree was negatively correlated with the neurological prognosis. KEY POINTS: • Recovery rates in patients with hyperechoic findings were lower than those of patients without lesions detected during intraoperative ultrasound. • The peak intensity of CEUS was higher in compressed zones than in the normal parts of the spinal cord. • Quantitative CEUS comparisons of the peak intensity and area under the curve at the compressed and normal levels of the spinal cord revealed differences that were inversely correlated to the recovery rate.

Application of the T1w/T2w mapping technique for spinal cord assessment in patients with degenerative cervical myelopathy.

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: To investigate signal changes on T1w/T2w signal intensity ratio maps within cervical cord in patients with degenerative cervical myelopathy (DCM). SETTING: Novosibirsk Neurosurgery Center, Russia. METHODS: A total of 261 patients with DCM and 42 age- and sex-matched healthy controls were evaluated using the T1w/T2w mapping method and spinal cord automatic morphometry. The T1w/T2w signal intensity ratio, which reflects white matter integrity, and the spinal cord cross-sectional area (CSA) were calculated and compared between the patients and the controls. In patients with DCM, the correlations between these parameters and neurological scores were also evaluated. RESULTS: The regional T1w/T2w ratio values from the cervical spinal cord at the level of maximal compression in patients with DCM were significantly lower than those in healthy controls (p < 0.001), as were the regional CSA values (p < 0.001). There was a positive correlation between the regional values of the T1w/T2w ratio and the values of the CSA at the level of maximal spinal cord compression. CONCLUSIONS: T1w/T2w mapping revealed that spinal cord tissue damage exists at the level of maximal compression in patients with DCM in association with spinal cord atrophy according to automatic morphometry. These changes were correlated with each other.