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

Diffusion Weighted Magnetic Resonance Imaging of Spinal Cord Injuries After Instrumented Fusion Stabilization

Diffusion-weighted magnetic resonance imaging (DW-MRI) is a promising technique for assessing spinal cord injury (SCI) that has historically been challenged by the presence of metallic stabilization hardware. This study leverages recent advances in metal-artifact resistant multi-spectral DW-MRI to enable diffusion quantification throughout the spinal cord even after fusion stabilization. Twelve participants with cervical spinal cord injuries treated with fusion stabilization and 49 asymptomatic able-bodied control participants underwent multi-spectral DW-MRI evaluation. Apparent diffusion coefficient (ADC) values were calculated in axial cord sections. Statistical modeling assessed ADC differences across cohorts and within distinct cord regions of the SCI participants (at, above, or below injured level). Computed models accounted for subject demographics and injury characteristics. ADC was found to be elevated at injured levels compared with non-injured levels (z = 3.2, p = 0.001), with ADC at injured levels decreasing over time since injury (z = -9.2, p < 0.001). Below the injury level, ADC was reduced relative to controls (z = -4.4, p < 0.001), with greater reductions after more severe injuries that correlated with lower extremity motor scores (z = 2.56, p = 0.012). No statistically significant differences in ADC above the level of injury were identified. By enabling diffusion analysis near fusion hardware, the multi-spectral DW-MRI technique allowed intuitive quantification of cord diffusion changes after SCI both at and away from injured levels. This demonstrates the approach's potential for assessing post-surgical spinal cord integrity throughout stabilized regions.

Feasibility of diffusion tensor imaging in cervical spondylotic myelopathy using MUSE sequence

BACKGROUND CONTEXT

The most frequent type of spinal cord injury is cervical spondylotic myelopathy (CSM). Conventional structural magnetic resonance imaging (MRI) is the gold diagnosis standard for CSM. Diffusion tensor imaging (DTI) could reflect microstructural changes in the spinal cord by tracing water molecular diffusion in early stages of CSM. However, due to the complex local anatomical structure and small field of view of the spinal cord, the imaging effect of traditional DTI imaging on the spinal cord is limited. MUSE (MUltiplexed Sensitivity-Encoding) -DTI is a novel diffusion-weighted imaging (DWI) sequence that achieves higher signal intensity through multiple excitation acquisition. MUSE sequence may improve the quality of spinal cord DTI imaging.

STUDY DESIGN

Prospective study.

PURPOSE

This study aimed to investigate the clinical diagnosis value of a novel protocol of MUSE-DTI in patients with cervical spondylotic myelopathy (CSM).

PATIENT SAMPLE

From August 2021 to March 2022, a total of 60 subjects (22-71 years) were enrolled, including 51 CSM patients (22 males, 29 females) and 9 healthy subjects (4 males and 5 females). Each subject underwent a MUSE-DTI examination and a clinical Japanese Orthopedic Association (JOA) scale.

OUTCOME MEASURES

We measured values of FA (Fractional Anisotropy), MD (Mean Diffusivity), AD (Axial Diffusivity), and RD (Radial Diffusivity), and collected the clinical JOA scores of each subject before the MR examination.

METHODS

A 3.0T MR scanner (Signa Architect, GE Healthcare) performed the MUSE-DTI sequence on each subject. The cervical canal stenosis of subjects was classified from grade 0 to grade Ⅲ according to the method of an MRI grading system. FA, MD, AD, and RD maps were generated by postprocessing MUSE-DTI data on the GE workstation. Regions of interest (ROIs) were manually drawn at the C2 vertebral body level and C2/3-C6/7 intervertebral disc levels by covering the whole spinal cord. The clinical severity of myelopathy of subjects was assessed by the clinical Japanese Orthopedic Association scale (JOA).

RESULTS

MUSE-DTI can acquire a high-resolution diffusion image compared to traditional DTI. The FAMCL values showed a decreasing trend from grade 0 to grade Ⅲ, while the MDMCL, ADMCL, and RDMCL values showed an overall increasing trend. Significant differences in MDMCL, ADMCL, and RDMCL values were found between adjacent groups among grades Ⅰ-Ⅲ (p<.05). The ADC2 values in CSM patients (grade I-Ⅲ) were significantly lower than in healthy individuals (grade 0) (p=.019). The clinical JOA score has a significant correlation with FAMCL (p=.035), MDMCL (p<.001), ADMCL (p<.001), and RDMCL (p<.001) values.

CONCLUSIONS

MUSE-DTI displayed a better image quality compared to traditional DTI. MUSE-DTI parameters displayed a grade-dependent trend. All the MUSE-DTI parameters at MCL were correlated with the clinical JOA scores. The ADC2 values can reflect the secondary damage of distal spinal cord. Therefore, MUSE-DTI could be a reliable biomarker for clinical auxiliary diagnosis of spinal cord injury severity in cervical spondylotic myelopathy.

Detecting microvascular invasion in hepatocellular carcinoma using the impeded diffusion fraction technique to sense macromolecular coordinated water

OBJECTIVES

Impeded diffusion fraction (IDF) is a novel and promising diffusion-weighted imaging (DWI) technique that allows for the detection of various diffusion compartments, including macromolecular coordinated water, free diffusion, perfusion, and cellular free water. This study aims to investigate the clinical potential of IDF-DWI in detecting microvascular invasion (MVI) in hepatocellular carcinoma (HCC).

METHODS

66 patients were prospectively included. Metrics derived from IDF-DWI and the apparent diffusion coefficient (ADC) were calculated. Multivariate logistic regression was employed to identify clinical risk factors. Diagnostic performance was evaluated using the area under the receiver operating characteristics curve (AUC-ROC), the area under the precision-recall curve (AUC-PR), and the calibration error (cal-error). Additionally, a power analysis was conducted to determine the required sample size.

RESULTS

The results suggested a significantly higher fraction of impeded diffusion (FID) originating from IDF-DWI in MVI-positive HCCs (p < 0.001). Moreover, the ADC was found to be significantly lower in MVI-positive HCCs (p = 0.019). Independent risk factors of MVI included larger tumor size and elevated alpha-fetoprotein (AFP) levels. The nomogram model incorporating ADC, FID, tumor size, and AFP level yielded the highest diagnostic accuracy for MVI (AUC-PR = 0.804, AUC-ROC = 0.783, cal-error = 0.044), followed by FID (AUC-PR = 0.693, AUC-ROC = 0.760, cal-error = 0.060) and ADC (AUC-PR = 0.570, AUC-ROC = 0.651, cal-error = 0.164).

CONCLUSION

IDF-DWI shows great potential in noninvasively, accurately, and preoperatively detecting MVI in HCC and may offer clinical benefits for prognostic prediction and determination of treatment strategy.

Changes in respiratory structure and function after traumatic cervical spinal cord injury: observations from spinal cord and brain

Respiratory difficulties and mortality following severe cervical spinal cord injury (CSCI) result primarily from malfunctions of respiratory pathways and the paralyzed diaphragm. Nonetheless, individuals with CSCI can experience partial recovery of respiratory function through respiratory neuroplasticity. For decades, researchers have revealed the potential mechanism of respiratory nerve plasticity after CSCI, and have made progress in tissue healing and functional recovery. While most existing studies on respiratory plasticity after spinal cord injuries have focused on the cervical spinal cord, there is a paucity of research on respiratory-related brain structures following such injuries. Given the interconnectedness of the spinal cord and the brain, traumatic changes to the former can also impact the latter. Consequently, are there other potential therapeutic targets to consider? This review introduces the anatomy and physiology of typical respiratory centers, explores alterations in respiratory function following spinal cord injuries, and delves into the structural foundations of modified respiratory function in patients with CSCI. Additionally, we propose that magnetic resonance neuroimaging holds promise in the study of respiratory function post-CSCI. By studying respiratory plasticity in the brain and spinal cord after CSCI, we hope to guide future clinical work.

Longitudinal multiparametric MRI of traumatic spinal cord injury in animal models

Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.

Direct jet coaxial electrospinning of axon-mimicking fibers for diffusion tensor imaging

Hollow polymer microfibers with variable microstructural and hydrophilic properties were proposed as building elements to create axon-mimicking phantoms for validation of diffusion tensor imaging (DTI). The axon-mimicking microfibers were fabricated in a mm-thick 3D anisotropic fiber strip, by direct jet coaxial electrospinning of PCL/polysiloxane-based surfactant (PSi) mixture as shell and polyethylene oxide (PEO) as core. Hydrophilic PCL-PSi fiber strips were first obtained by carefully selecting appropriate solvents for the core and appropriate fiber collector rotating and transverse speeds. The porous cross-section and anisotropic orientation of axon-mimicking fibers were then quantitatively evaluated using two ImageJ plugins-nearest distance (ND) and directionality based on their scanning electron microscopy (SEM) images. Third, axon-mimicking phantom was constructed from PCL-PSi fiber strips with variable porous-section and fiber orientation and tested on a 3T clinical MR scanner. The relationship between DTI measurements (mean diffusivity [MD] and fractional anisotropy [FA]) of phantom samples and their pore size and fiber orientation was investigated. Two key microstructural parameters of axon-mimicking phantoms including normalized pore distance and dispersion of fiber orientation could well interpret the variations in DTI measurements. Two PCL-PSi phantom samples made from different regions of the same fiber strips were found to have similar MD and FA values, indicating that the direct jet coaxial electrospun fiber strips had consistent microstructure. More importantly, the MD and FA values of the developed axon-mimicking phantoms were mostly in the biologically relevant range.

Utilizing Deep Learning for X-ray Imaging: Detecting and Classifying Degenerative Spinal Conditions

Background Degenerative spinal conditions (DSCs) involve a diverse set of pathologies that significantly impact health and quality of life, affecting many individuals at least once during their lifetime. Treatment approaches are varied and complex, reflecting the intricacy of spinal anatomy and kinetics. Diagnosis and management pose challenges, with the accurate detection of lesions further complicated by age-related degeneration and surgical implants. Technological advancements, particularly in artificial intelligence (AI) and deep learning, have demonstrated the potential to enhance detection of spinal lesions. Despite challenges in dataset creation and integration into clinical settings, further research holds promise for improved patient outcomes. Methods This study aimed to develop a DSC detection and classification model using a Kaggle dataset of 967 spinal X-ray images at the Department of Neurosurgery of Arrowhead Regional Medical Center, Colton, California, USA. Our entire workflow, including data preprocessing, training, validation, and testing, was performed by utilizing an online-cloud based AI platform. The model's performance was evaluated based on its ability to accurately classify certain DSCs (osteophytes, spinal implants, and foraminal stenosis) and distinguish these from normal X-rays. Evaluation metrics, including accuracy, precision, recall, and confusion matrix, were calculated.  Results The model achieved an average precision of 0.88, with precision and recall values of 87% and 83.3%, respectively, indicating its high accuracy in classifying DSCs and distinguishing these from normal cases. Sensitivity and specificity values were calculated as 94.12% and 96.68%, respectively. The overall accuracy of the model was calculated to be 89%.  Conclusion These findings indicate the utility of deep learning algorithms in enhancing early DSC detection and screening. Our platform is a cost-effective tool that demonstrates robust performance given a heterogeneous dataset. However, additional validation studies are required to evaluate the model's generalizability across different populations and optimize its seamless integration into various types of clinical practice.

Porcine Model of the Growing Spinal Cord-Changes in Diffusion Tensor Imaging Parameters

Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique that has promising applications for the objective assessment of the microstructure of the spinal cord. This study aimed to verify the parameters obtained using DTI change during the growth process. We also wanted to identify if the DTI values change on the course of the spinal cord. The model organism was a healthy growing porcine spinal cord (19 pigs, Polish White, weight 24-120 kg, mean 48 kg, median 48 kg, age 2.5-11 months, mean 5 months, median 5.5 months). DTI parameters were measured in three weight groups: up to 29 kg (five pigs), 30-59 kg (six pigs), and from 60 kg up (eight pigs). DTI was performed with a 1.5 Tesla magnetic resonance scanner (Philips, Ingenia). Image post-processing was done using the Fiber Track package (Philips Ingenia workstation) by manually drawing the regions of interest (nine ROIs). The measurements were recorded for three sections: the cervical, thoracolumbar and lumbar segments of the spinal cord at the C4/C5, Th13/L1, and L4/L5 vertebrae levels. In each case, one segment was measured cranially and one caudally from the above-mentioned places. The values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were obtained for each ROIs and compared. It is shown that there is a correlation between age, weight gain, and change in FA and ADC parameters. Moreover, it is noted that, with increasing weight and age, the FA parameter increases and ADC decreases, whereas the FA and ADC measurement values did not significantly change between the three sections of the spinal cord. These findings could be useful in determining the reference values for the undamaged spinal cords of animals and growing humans.

Denoising of diffusion MRI in the cervical spinal cord - effects of denoising strategy and acquisition on intra-cord contrast, signal modeling, and feature conspicuity

Quantitative diffusion MRI (dMRI) is a promising technique for evaluating the spinal cord in health and disease. However, low signal-to-noise ratio (SNR) can impede interpretation and quantification of these images. The purpose of this study is to evaluate several dMRI denoising approaches on their ability to improve the quality, reliability, and accuracy of quantitative diffusion MRI of the spinal cord. We evaluate three denoising approaches (Non-Local Means, Marchenko-Pastur PCA, and a newly proposed Patch2Self algorithm) and conduct five experiments to validate the denoising performance on clinical-quality and commonly-acquired dMRI acquisitions: 1) a phantom experiment to assess denoising error and bias; 2) a multi-vendor, multi-acquisition open experiment for both qualitative and quantitative evaluation of noise residuals; 3) a bootstrapping experiment to estimate uncertainty of parametric maps; 4) an assessment of spinal cord lesion conspicuity in a multiple sclerosis group; and 5) an evaluation of denoising for advanced parametric multi-compartment modeling. We find that all methods improve signal-to-noise ratio and conspicuity of MS lesions in individual diffusion weighted images (DWIs), but MPPCA and Patch2Self excel at improving the quality and intra-cord contrast of diffusion weighted images - removing signal fluctuations due to thermal noise while improving precision of estimation of diffusion parameters even with very few DWIs (i.e., 16-32) typical of clinical acquisitions. These denoising approaches hold promise for facilitating reliable diffusion observations and measurements in the spinal cord to investigate biological and pathological processes.

Quantifying Intraparenchymal Hemorrhage after Traumatic Spinal Cord Injury: A Review of Methodology

Intraparenchymal hemorrhage (IPH) after a traumatic injury has been associated with poor neurological outcomes. Although IPH may result from the initial mechanical trauma, the blood and its breakdown products have potentially deleterious effects. Further, the degree of IPH has been correlated with injury severity and the extent of subsequent recovery. Therefore, accurate evaluation and quantification of IPH following traumatic spinal cord injury (SCI) is important to define treatments' effects on IPH progression and secondary neuronal injury. Imaging modalities, such as magnetic resonance imaging (MRI) and ultrasound (US), have been explored by researchers for the detection and quantification of IPH following SCI. Both quantitative and semiquantitative MRI and US measurements have been applied to objectively assess IPH following SCI, but the optimal methods for doing so are not well established. Studies in animal SCI models (rodent and porcine) have explored US and histological techniques in evaluating SCI and have demonstrated the potential to detect and quantify IPH. Newer techniques using machine learning algorithms (such as convolutional neural networks [CNN]) have also been studied to calculate IPH volume and have yielded promising results. Despite long-standing recognition of the potential pathological significance of IPH within the spinal cord, quantifying IPH with MRI or US is a relatively new area of research. Further studies are warranted to investigate their potential use. Here, we review the different and emerging quantitative MRI, US, and histological approaches used to detect and quantify IPH following SCI.

Quantitative physical performance tests can effectively detect Degenerative Cervical Myelopathy: A systematic review and meta-analysis

PURPOSE

This review aimed to identify effective physical performance tests (PPT) as clinical outcome indicators for detecting and monitoring degenerative cervical myelopathy (DCM).

METHODS

A comprehensive literature search was performed on seven electronic databases on the effectiveness in detection and monitoring of DCM by PPT. All included studies were reviewed and undergone quality assessments on the risk-of-bias by Newcastle-Ottawa Scale and were pooled by random-effect analysis with level of significance at 0.05. Homogeneity among studies was assessed by I²-statistics and effect of PPT was confirmed by Cohen's d effect size and confidence intervals.

RESULTS

Totally, 3111 articles were retrieved, and 19 studies were included for review and meta-analysis. There were 13 studies investigating PPT regarding the upper limbs and 12 studies regarding the lower limbs. Performance in 10-second-Grip-and-Release Test (G&R) and 9-Hole-Peg Test (9HPT) was studied in 10 and 3 articles, respectively, while 10-second-Stepping Test (SST), 30-meter-Walking Test (30MWT) and Foot-Tapping Test (FTT) for lower limbs were studied in 5, 4, and 3 articles correspondingly. Only 1 study utilized the Triangle-Stepping Test. High-quality study with fair risk-of-bias was revealed from Newcastle-Ottawa scale. Large effect size facilitated detection and monitoring in DCM was unveiling for G&R, 9HPT, SST, and 30MWT. FTT, while also effective, was hindered by a high-degree heterogeneity in the meta-analysis.

CONCLUSION

Effective PPT including G&R, 9HPT, SST, 30MWT, and FTT was identified for disease detection and monitoring in DCM.

Role of diffusion tensor imaging and tractography in spinal cord injury

Spinal cord injuries pose grave medical and socioeconomic burdens warranting measures for early diagnosis, triaging, prognostication and therapeutics. Imaging has since long played a pivotal role in this regard, with continuing research and technological advancements opening newer frontiers. One such advanced Magnetic resonance (MR) technique is Diffusion tensor imaging (DTI) which assesses cord microstructure by tracking the movement of water molecules in biological tissues. DTI utilizes the principle of anisotropy exhibited by the normal compact white matter (WM) tracts of the cord, in which direction-dependent water molecular motion is seen along the axonal axis. Disruption of this complex structure in response to injury alters the movement of these molecules, interrupting anisotropy and thereby DTI metrics. Evaluation of DTI images can be done both by quantitative indices, of which fractional anisotropy (FA) and mean diffusivity (MD) are the most commonly used and by qualitative fiber tracking (tractography) methods in which three-dimensional WM tracts are reconstructed by algorithmic post-processing. Reduced FA is consistently seen at injury sites as a direct consequence of disturbance of anisotropy. Diffusivity values are however more variable with both high and low values recorded across studies. 3D tractography images allow visual assessment of cord integrity, morphology, and orientation. Significant correlation is found between DTI parameters and various spinal injury scores. Furthermore, DTI also helps in accurate lesion mapping and in assessing cord changes distant from injury epicenter providing a holistic evaluation. From its inception, consistent progress in the understanding and application of DTI has effectuated its clinical utility and impact. Incorporation into day-to-day diagnostics is however still challenging, due to suboptimal image acquisition, difficult post-processing, and lack of standardized protocols & image interpretation guidelines. Further research with technical validation, development of normative and disease data sets, and histological confirmation will help establish this novel technique in routine diagnostics.

Spinal Tractography as a Potential Prognostic Tool in Spinal Cord Injury: A Systematic Review

Magnetic resonance imaging is considered the most accurate examination to study the spinal cord. Nevertheless, the use of diffusion tensor imaging (DTI) can demonstrate additional key details about spinal cord lesions. We examined the literature to investigate and discuss the role, limitations, and possible evolution as a prognostic tool of DTI in spinal cord injury (SCI). For this systematic literature review, a detailed search was performed using PubMed (2005-2021), Cochrane Database of Systematic Reviews (2016-2021), and Cochrane Central Register of Controlled Trials (2016-2021). To be included, studies had to report the use of DTI in SCIs, its clinical relevance, and its use as a prognostic tool. We identified 17 studies comprising 299 patients. The mean age of patients was 41.22 ± 10.62 years. There was a prevalence of males (70.9%) compared with females (29.1%). The main spinal cord tract involved and studied in SCIs was the cervical tract (57.5%), followed by conus terminalis (15.4%) and dorsal tract (13.7%). In all studies based on American Spine Injury Association impairment scale score for neurological assessment, a correlation was found between FA values and American Spine Injury Association impairment scale: patients with complete SCI had a statistically significative lower FA value at the injured site compared with patients with incomplete SCI. Published clinical studies showed promising results for the utility of DTI parameters as noninvasive biomarkers in SCI grade evaluation, remaining an evolving area of further investigation.

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.

Role of Whole-Body Computed Tomography Scan to Avoid Missed Foreign Body in Patients with Multiple Stab Injury: A Rare Case of Retained Impaled Knife Blade with Intact Neurology

Nonmissile penetrating spine injury (NMPSI) is usually encountered in young men, secondary to knife-inflicted injuries. Such injuries often present with complete or incomplete neurodeficit. We hereby report a case of NMPSI (due to impaled knife blade) in the cervical spine, who presented with intact neurology. She was managed by foreign body removal, dural repair, and cerebrospinal fluid (CSF) diversion with lumbar drain. We performed postoperative magnetic resonance imaging with diffusion tensor imaging and tractography to ascertain the cord status. The case highlights the importance of whole-body computed tomography in patients with multiple stab wounds and the use of CSF diversion in such situations.

Assessment of acute traumatic cervical spinal cord injury using conventional magnetic resonance imaging in combination with diffusion tensor imaging-tractography: a retrospective comparative study

PURPOSE

The application of conventional magnetic resonance imaging (MRI) in combination with diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) to diagnose acute traumatic cervical SCI has not been studied. This study explores the role of MRI with DTI-DTT in the diagnosis of acute traumatic cervical spinal cord injury (SCI).

METHODS

Thirty patients with acute traumatic cervical SCI underwent conventional MRI and DTI-DTT. Conventional MRI was used to detect the intramedullary lesion length (IMLL) and intramedullary hemorrhage length (IMHL). DTI was used to detect the spinal cord's fractional anisotropy (FA) and apparent diffusion coefficient value, and DTT detected the imaginary white matter fiber volume and the connection rates of fiber tractography (CRFT). Patients' neurological outcome was determined using the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades.

RESULTS

Patients were divided into group A (without AIS grade conversion) and group B (with AIS grade conversion). The IMLL and IMHL of group A were significantly higher than those of group B. The FA and CRFT of group A were significantly lower than those of group B. The final AIS grade was negatively correlated with the IMLL and IMHL, and positively correlated with the FA and CRFT. According to imaging features based on conventional MRI and DTI-DTT, we propose a novel classification and diagnostic procedure.

CONCLUSIONS

The combination of conventional MRI with DTI-DTT is a valid diagnostic approach for SCI. Lower IMLL and IMHL, and higher FA value and CRFT are linked to better neurological outcomes.

Levetiracetam Attenuates the Spinal Cord Injury Induced by Acute Trauma via Suppressing the Expression of Perforin

The spinal cord injury (SCI) is one of the major reasons causing the motor dysfunctions of the patients. At present, few therapeutic strategies can effectively improve the symptom of SCI. Levetiracetam has been confirmed to alleviate the injury of nerve cells, while its functions in SCI remains unclear. In this study, C57BL/6J mice were used to establish SCI models to observe the effect of levetiracetam on SCI. The mice were fed with 180 mg/kg levetiracetam when suffering from SCI, and Basso mouse score (BMS) and CatWalk-assisted gait analysis were used to observe the motor functions of the mice. Nissl staining and TUNEL staining were used to observe the injury of nerve cells. The abundance of inflammatory factors was measured by ELISA. The permeability of blood-spinal cord barrier (BSCB) in mice was detected with macrophage infiltration analysis. Moreover, the abundance of perforin in the tissues was detected by western blot. The results showed that the SCI mice treated with levetiracetam exhibited lighter motor dysfunction compared with the mice treated with saline. Levetiracetam can effectively reduce the inflammatory reactions and alleviate apoptosis of the nerve cells. Moreover, levetiracetam remarkably decreased the BSCB permeability of SCI mice. Besides, it was also found that levetiracetam can significantly inhibit the expression of perforin. In conclusion, this study suggests that levetiracetam can attenuate the injury of BSCB to block the progression of SCI via suppressing the expression of perforin.

Targeting neurotrophin and nitric oxide signaling to treat spinal cord injury and associated neurogenic bladder overactivity

Purpose or the research

Nearly 300,000 people are affected by spinal cord injury (SCI) with approximately 18,000 new cases annually, according to the National SCI Statistics Center. SCI affects physical mobility and impairs the function of multiple internal organs to cause lower urinary tract (LUT) dysfunctions manifesting as detrusor sphincter dyssynergia (DSD) and neurogenic detrusor overactivity (NDO) with detrimental consequences to the quality of life and increased morbidity. Multiple lines of evidence now support time dependent evolution of the complex SCI pathology which requires a multipronged treatment approach of immediate, specialized care after spinal cord trauma bookended by physical rehabilitation to improve the clinical outcomes. Instead of one size fits all treatment approach, we propose adaptive drug treatment to counter the time dependent evolution of SCI pathology, with three small molecule drugs with distinctive sites of action for the recovery of multiple functions.

Principal results

Our findings demonstrate the improvement in the recovery of hindlimb mobility and bladder function of spinal cord contused mice following administration of small molecules targeting neurotrophin receptors, LM11A-31 and LM22B-10. While LM11A-31 reduced the cell death in the spinal cord, LM22B-10 promoted cell survival and axonal growth. Moreover, the soluble guanylate cyclase (sGC) activator, cinaciguat, enhanced the revascularization of the SCI injury site to promote vessel formation, dilation, and increased perfusion.

Major conclusions

Our adaptive three drug cocktail targets different stages of SCI and LUTD pathology: neuroprotective effect of LM11A-31 retards the cell death that occurs in the early stages of SCI; and LM22B-10 and cinaciguat promote neural remodeling and reperfusion at later stages to repair spinal cord scarring, DSD and NDO. LM11A-31 and cinaciguat have passed phase I and IIa clinical trials and possess significant potential for accelerated clinical testing in SCI/LUTD patients.

Clinical Utility of Diffusion Tensor Imaging as a Biomarker to Identify Microstructural Changes in Pediatric Spinal Cord Injury

Background

Lack of clarity about the neurological consequence of spinal cord injury (SCI) in children causes speculation about diagnoses, recovery potential, and treatment effectiveness. Diffusion tensor imaging (DTI) has shown promising results as a biomarker to evaluate spinal cord integrity at a microstructural level.

Objectives

To look at the difference between pediatric participants with and without SCI to determine which DTI metrics best categorize spinal cord tissue damage and to correlate DTI metrics with two clinical measures: Capabilities of the Upper Extremity Test (CUE-T) and Spinal Cord Independence Measure version III (SCIM-III).

Methods

This single-site, prospective study included pediatric participants with SCI (n = 26) and typically developed (TD) control subjects (n = 36). All participants underwent two magnetic resonance imaging (MRI) scans on a 3T MR scanner. Participants with SCI also completed the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), CUE-T, and SCIM-III outcomes measures.

Results

This study found significant strength of association between fractional anisotropy (FA) and upper extremity muscle strength (UEMS) in participants with SCI. Most DTI parameters showed a significant difference between participants with SCI and TD participants and a moderate correlation with the CUE-T total score. Regional effects on group differences were found to be significant.

Conclusion

This study demonstrates the strength of association between DTI parameters and clinical measures in the pedantic SCI population. It illustrates DTI as a potential biomarker of SCI location and severity in the pediatric SCI population.

Peripheral white blood cell responses as emerging biomarkers for patient stratification and prognosis in acute spinal cord injury

PURPOSE OF REVIEW

To date, prognostication of patients after acute traumatic spinal cord injury (SCI) mostly relies on the neurological assessment of residual function attributed to lesion characteristics. With emerging treatment candidates awaiting to be tested in early clinical trials, there is a need for wholistic high-yield prognostic biomarkers that integrate both neurogenic and nonneurogenic SCI pathophysiology as well as premorbid patient characteristics.

RECENT FINDINGS

It is becoming clearer that effective prognostication after acute SCI would benefit from integrating an assessment of pathophysiological changes on a systemic level, and with that, extend from a lesion-centric approach. Immunological markers mirror tissue injury as well as host immune function and are easily accessible through routine blood sampling. New studies have highlighted the value of circulating white blood cells, neutrophils and lymphocytes in particular, as prognostic systemic indicators of SCI severity and outcomes.

SUMMARY

We survey recent advances in methods and approaches that may allow for a more refined diagnosis and better prognostication after acute SCI, discuss how these may help deepen our understanding of SCI pathophysiology, and be of use in clinical trials.

Elderly traumatic central cord syndrome in the United States: a review of management and outcomes

INTRODUCTION

As the incidence of elderly spinal cord injury rises, improved understanding of risk profiles and outcomes is needed. This review summarizes clinical characteristics, management, and outcomes specific to the elderly (≥65-years) with acute traumatic central cord syndrome in the United States.

EVIDENCE AQUISITION

Literature review of the PubMed, Embase, and CINAHL databases (01/2007-03/2020) regarding elderly subjects with acute traumatic central cord syndrome.

EVIDENCE SYNTHESIS

Nine studies met inclusion criteria. Acute traumatic central cord syndrome was more common among married (50%), Caucasian (22-71%) males (63-86%) with an annual income <40,999 U.S. dollars (30%). Mechanisms consisted predominantly of traumatic falls (32-55%) and motor vehicle collisions (15-34%), with admission American Spinal Injury Association Impairment Scale grades D (25-79%) and C (21-51%). Mortality was 2-3%. American Spinal Injury Association Impairment Scale motor score, maximum canal compromise, and extent of parenchymal damage were predictors of one-year recovery. Greater comorbidities (heart failure, weight loss, coagulopathy, diabetes), lower income (<51,000 U.S. dollars), and age ≥80 were predictors of mortality. A substantial cohort underwent surgery (40-45%). Elderly patients were less likely to receive surgical intervention, and surgery timing had variable effects on recovery.

CONCLUSIONS

Elderly patients with acute traumatic central cord syndrome are uniquely at risk due to cumulative comorbidities, protracted recovery times, and unclear effects of surgical timing on outcomes. Prospective research should focus on validating age-specific risk factors, formalizing surgical indications, and delineating the impact of time to surgery on acute and long-term outcomes for this condition.

Evaluating the Severity and Prognosis of Acute Traumatic Cervical Spinal Cord Injury: A Novel Classification Using Diffusion Tensor Imaging and Diffusion Tensor Tractography

STUDY DESIGN

Retrospective observational cohort study.

OBJECTIVE

We explored the relationship between diffusion tensor imaging (DTI) parameters and prognosis in patients with acute traumatic cervical spinal cord injury (ATCSCI).

SUMMARY OF BACKGROUND DATA

DTI has been used to diagnose spinal cord injury; nevertheless, its role remains controversial.

METHODS

We analyzed retrospectively 24 patients with ATCSCI who were examined using conventional T2-weighted imaging and DTI. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were recorded at the injured site. Diffusion tensor tractography (DTT) was used to measure the spinal cord white matter fiber volume (MWFV). American Spinal Injury Association (ASIA) grades were recorded. Correlations between DTI parameters and ASIA scores were evaluated using Spearman correlation coefficients.

RESULTS

FA values at injured sites were significantly lower than those of the control group, whereas ADC values in injured and control groups were not significantly different. DTT revealed that ATCSCI could be divided into four types: Type A1-complete rupture of spinal cord white matter fiber (MWF); Type A2-partial rupture of MWF; Type B-most MWF retained with severe compression or abnormal fiber conduction direction; and Type C-MWF basically complete with slight compression. Preoperative physical examinations revealed complete injury (ASIA A) in patients with A1 (n = 4) and A2 (n = 4). The ASIA grades or scores of A2 were improved to varying degrees, whereas there was no significant improvement in A1. FA values and MWFV of ASIA B, C, and D were significantly higher than those of ASIA A. FA and MWFV were correlated with ASIA motor score preoperatively and at final follow-up.

CONCLUSION

We propose a classification for the severity of ATCSCI based on DTI and DTT that may explain why some patients with ASIA A recover, whereas others do not.Level of Evidence: 4.

Acute Traumatic Spinal Cord Injury

Traumatic spinal cord injury is a common neurologic insult worldwide that can result in severe disability. Early stabilization of the patient's airway, breathing, and circulation as well as cervical and thoracolumbar spinal immobilization is necessary to prevent additional injury and optimize outcomes. Computed tomography (CT) scan and magnetic resonance imaging (MRI) of the spinal column can assist with determining the extent of bony and ligamentous injury, which will guide surgical management. With or without surgical intervention, patients with spinal cord injury require intensive care unit management and close observation to monitor for potential complications.

The Role of Diffusion Tensor Imaging and Diffusion Tensor Tractography in the Assessment of Acute Traumatic Thoracolumbar Spinal Cord Injury

BACKGROUND

This study explored diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) to assess the prognosis of thoracolumbar spinal cord injury (SCI).

METHODS

Twenty patients with acute traumatic thoracolumbar complete SCI (T1-L1, American Spinal Injury Association Impairment Scale [AIS] grade A) underwent conventional magnetic resonance imaging and DTI examinations. DTI measured the fractional anisotropy (FA) and apparent diffusion coefficient adjacent to the lesion epicenter. DTT was used to detect the white matter fiber morphology and measure the imaginary white matter fiber volume and connection rates of fiber tractography (CRFT). The patients' neurological functions were evaluated by the AIS grades.

RESULTS

At the final-follow-up, among the 20 patients with AIS grade A, 15 maintained the AIS grade (group A), and 5 patients showed improvement of AIS grade (group B). Group A's mean FA value was significantly lower than that of group B, whereas the mean apparent diffusion coefficient value among the 2 groups showed no significant difference. The white matter fibers of most patients in group A were completely ruptured (11/15), but the white matter fibers of all patients in group B were retained in different number (5/5). The mean CRFT of group B was significantly higher than that of group A (P < 0.05). The improvement of AIS grade was slightly positively correlated with FA values and highly positively correlated with CRFT.

CONCLUSIONS

The prognosis of complete thoracolumbar SCI may be related to the FA value and the CRFT. The application of DTI and DTT may optimize the diagnosis of thoracolumbar SCI.

Effect of b Value on Imaging Quality for Diffusion Tensor Imaging of the Spinal Cord at Ultrahigh Field Strength

Objective

To explore the optimal b value setting for diffusion tensor imaging of rats' spinal cord at ultrahigh field strength (7 T).

Methods

Spinal cord diffusion tensor imaging data were collected from 14 rats (5 healthy, 9 spinal cord injured) with a series of b values (200, 300, 400, 500, 600, 700, 800, 900, and 1000 s/mm²) under the condition that other scanning parameters were consistent. The image quality (including image signal-to-noise ratio and image distortion degree) and data quality (i.e., the stability and consistency of the DTI-derived parameters, referred to as data stability and data consistency) were quantitatively evaluated. The min-max normalization method was used to process the calculation results of the four indicators. Finally, the image and data quality under each b value were synthesized to determine the optimal b value.

Results

b = 200 s/mm² and b = 900 s/mm² ranked in the top two of the comprehensive evaluation, with the best image quality at b = 200 s/mm² and the best data quality at b = 900 s/mm².

Conclusion

Considering the shortcomings of the ability of low b values to reflect the microstructure, b = 900 s/mm² can be used as the optimal b value for 7 T spinal cord diffusion tensor scanning.

Longitudinal changes in DTI parameters of specific spinal white matter tracts correlate with behavior following spinal cord injury in monkeys

This study aims to evaluate how parameters derived from diffusion tensor imaging reflect axonal disruption and demyelination in specific white matter tracts within the spinal cord of squirrel monkeys following traumatic injuries, and their relationships to function and behavior. After a unilateral section of the dorsal white matter tract of the cervical spinal cord, we found that both lesioned dorsal and intact lateral tracts on the lesion side exhibited prominent disruptions in fiber orientation, integrity and myelination. The degrees of pathological changes were significantly more severe in segments below the lesion than above. The lateral tract on the opposite (non-injured) side was minimally affected by the injury. Over time, RD, FA, and AD values of the dorsal and lateral tracts on the injured side closely tracked measurements of the behavioral recovery. This unilateral section of the dorsal spinal tract provides a realistic model in which axonal disruption and demyelination occur together in the cord. Our data show that specific tract and segmental FA and RD values are sensitive to the effects of injury and reflect specific behavioral changes, indicating their potential as relevant indicators of recovery or for assessing treatment outcomes. These observations have translational value for guiding future studies of human subjects with spinal cord injuries.

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).

Imaging findings of penetrating spinal cord injuries secondary to stab wounds on magnetic resonance imaging in a tertiary trauma unit, South Africa

BACKGROUND

In South Africa, the leading cause of spinal cord injuries is motor vehicle accidents, followed by violence-related injuries, including gunshot injuries and stab wounds. Controversy regarding management persists. Magnetic resonance imaging (MRI) is the gold standard to rule out surgical causes of neurological deficit.

OBJECTIVES

To determine the spectrum of imaging findings in penetrating spinal cord injuries, specifically related to stab wounds, in a Tertiary Academic Hospital in the Free State province and whether these imaging findings influenced immediate surgical decision-making and outcomes of patients.

METHOD

Consecutive sampling was used to retrospectively select patients who presented with spinal penetrating injuries secondary to stab wounds during the period 01 August 2013-30 September 2016 and received MRI investigation. Fifty-six patients were included. Magnetic resonance imaging investigations were reviewed by the authors, with documentation of MRI findings, relevant patient demographics and clinical information into Excel spread sheets. Statistical analysis was performed by the Biostatistics Department of the University of the Free State.

RESULTS

The most common MRI finding was a high signal intensity wound tract (96.6%), followed by cord signal changes (91.1%) and cord oedema (82.1%). Thirty-nine extra-axial collections were diagnosed in 30 penetrating injuries, of which only one had spinal compressive effects. Four patients (7.1%) demonstrated pseudo-meningoceles. None of the included patients had an indication for emergency spinal surgery on review of imaging.

CONCLUSION

Magnetic resonance imaging findings did not alter the surgical course of action in our study patients. Despite this, MRI is a valuable modality in evaluation of penetrating spinal cord injuries in the post-traumatic phase (<24 h) for the presence of pseudo-meningoceles that pose an infection and delayed complication risk.