Advances in imaging of vertebral and spinal cord injury

Value of MRI in the cervical spine imaging series of trauma patients: A state-of-the-art review

INTRODUCTION

Clinical decision protocols for evaluation and assessment of traumatic cervical spine injuries (TCSI) lean more towards the use of CT imaging. Investigation with MRI is therefore considered unnecessary following negative CT findings according to some local protocols. This review aims to explore what benefits MRI may offer in the clinical management of TCSI patients.

METHODS

A systematic search of the literature was conducted in the following databases: AMED, CINAHL, EMBASE and MEDLINE using defined key terms and synonyms optimised for each database. The eligible articles were subjected to data extraction and thematic synthesis.

RESULTS

The initial electronic search yielded 2527 articles. Of these, 15 articles remained following the application of a pre-defined inclusion criteria and full-text assessment. Four themes (mechanism of injury, type of patient, injuries detected on MRI, significance of injuries detected on MRI) were developed relating to the usage and value of MRI in the management of CSI.

DISCUSSION

Our findings indicate that MRI may be very valuable in some situations for the evaluation of TCSI, however, its usage must be cautiously considered on a case-by-case basis in light of additional clinical benefit, patient safety and resource availability following a normal CT scan or in conjunction with CT or projection radiography where appropriate.

IMPLICATIONS FOR PRACTICE

MRI may serve as a confirmatory test in the management pathway of TCSI based on individual clinical needs. Consideration for key limitations (e.g., patients' cooperation) and accessibility challenges (e.g., cost) against the clinical benefit to the patient must be noted. Development of centre-specific policies from standard trauma imaging protocols may be essential for the timely management of TCSI.

Determination of the Efficiency of Magnetic Resonance Imaging in the Evaluation of Compressive Myelopathy

Background The phrase "compressive myelopathy" refers to compression of the spinal cord, either internally or externally. This compression might arise from various sources such as a herniated disc, post-traumatic compression, and epidural abscess as well as epidural or intradural neoplasms. Magnetic resonance imaging (MRI) plays a crucial role in differentiating between compressive and non-compressive myelopathy. After eliminating compressive lesions, attention is directed toward intrinsic cord-related causes of acute myelopathy including vascular, infectious, and inflammatory pathologies. Aims The study aimed to assess different etiologies of compressive myelopathy, analyze the MRI features of spinal cord compressive lesions, classify the lesions depending on site, and correlate MRI findings with intraoperative findings and histopathology in operated cases. Material & methods A total of 50 patients, who exhibited clinical symptoms indicative of compressive myelopathy sent to the Radiology department, Rangaraya Medical College (RMC), Kakinada for MRI spine were included in the study. It's an observational cross-sectional study. Statistical Package for Social Sciences (SPSS) version 22.0 (IBM Corp., Armonk, USA) was used for statistical calculations. Result Among the 50 cases of compressive myelopathy, the etiologies are distributed as follows: trauma (22 cases), infection (12 cases), primary neoplasm (eight cases), and secondary neoplasm (eight cases); extradural compressive lesions (84%) and Intradural-extramedullary lesions (16%). Conclusion Utilizing MRI successfully assessed the spinal cord integrity and characterized spinal tumors. Consequently, the study concludes that MRI is a highly definitive, sensitive, and accurate tool for evaluating compressive myelopathy.

The Spine is the Tree of Life: A Systematic Review and Meta-Analysis of the Radiographic Findings Related to Spinal Injuries in Athletes

This review article explores spinal injuries in athletes participating in various sporting activities. It also highlights the various mechanisms of injuries that contribute to spinal injuries in each sport. Electronic databases such as PubMed, Cochrane Library, Web of Science, Embase, MEDLINE Ovid, and Google Scholar were searched for articles from 2000 to 2022 on spine injuries in sports and radiological studies discussing the various injury patterns among athletes. Studies were scoured in accordance with the inclusion criteria, and relevant data such as the number of participants, sporting activities, spine injuries, and outcomes were retrieved. Fifteen articles that met the inclusion criteria were included in the study. Cervical spine injuries are common in athletes who participate in contact sports such as football. Similarly, athletes in collision sports such as football, rugby, and hockey are likely to suffer stingers due to traction and compression injuries. Players engaged in such as soccer, baseball, and swimming, are likely to suffer from spondylolysis. Soccer players are more prone to multiple lesions compared to athletes in sports such as baseball because the sport involves training exercises such as jogging and running without kicking any ball. In swimmers, spondylolysis is common in breaststroke and butterfly styles since they involve repeated flexion and hyperextension of the lumbar spine. CT is essential for diagnosing spondylolysis as it demonstrates the lesions more accurately. Ice hockey is associated with a significant incidence of cervical spine injuries, mostly due to players being constantly checked/pushed from behind. Spine injuries are common in elite athletes across several sports. About 10% of spinal injuries in the United States result from sports activities. In diagnosing spine injuries, imaging modalities such as MRI, CT, or plain radiographs are essential. From a radiologist's perspective, these tests help immensely in deciding which treatment is required for a particular athlete or how the injury can be optimally managed. Achieving recovery from a specific spine injury usually depends on the kind of injury and the rehabilitation process the athletes undergo before returning to play.

Acute cervical spinal cord injury after head and neck surgery: A CARE case report

OBJECTIVE

To describe and analyze a case of acute spinal cord injury after head and neck surgery.

DESCRIPTION

One hour after left lobo-isthmectomy under laryngeal neuromonitoring for a 3-cm EU-TIRADS 4 - Bethesda 4 thyroid nodule in a 48-year-old euthyroid male without any known comorbidity, left hemiparesis occurred. Cervical spine MRI showed an anteromedial herniated C6-7 disk with medullary compression. The disk was resected, compression was released and C6-7 fusion was performed via an anterior cervical approach on postoperative day 1. Postoperative course was unremarkable, with complete recovery of motion within 2 days. One month later, neurological clinical examination was normal and interview revealed left cervicalgia with onset a few days prior to lobo-isthmectomy. One year later, at the time of writing, the patient was doing fine.

CONCLUSION

Otorhinolaryngologists and head and neck surgeons must be aware of the risk of acute cervical spinal injury after cervical mobilization in head and neck surgery, and should take all measures to avoid this exceptional but dramatic complication.

Tethered spinal cord tension assessed via ultrasound elastography in computational and intraoperative human studies

BACKGROUND

Tension in the spinal cord is a trademark of tethered cord syndrome. Unfortunately, existing tests cannot quantify tension across the bulk of the cord, making the diagnostic evaluation of stretch ambiguous. A potential non-destructive metric for spinal cord tension is ultrasound-derived shear wave velocity (SWV). The velocity is sensitive to tissue elasticity and boundary conditions including strain. We use the term Ultrasound Tensography to describe the acoustic evaluation of tension with SWV.

METHODS

Our solution Tethered cord Assessment with Ultrasound Tensography (TAUT) was utilized in three sub-studies: finite element simulations, a cadaveric benchtop validation, and a neurosurgical case series. The simulation computed SWV for given tensile forces. The cadaveric model with induced tension validated the SWV-tension relationship. Lastly, SWV was measured intraoperatively in patients diagnosed with tethered cords who underwent treatment (spinal column shortening). The surgery alleviates tension by decreasing the vertebral column length.

RESULTS

Here we observe a strong linear relationship between tension and squared SWV across the preclinical sub-studies. Higher tension induces faster shear waves in the simulation (R2 = 0.984) and cadaveric (R2 = 0.951) models. The SWV decreases in all neurosurgical procedures (p < 0.001). Moreover, TAUT has a c-statistic of 0.962 (0.92-1.00), detecting all tethered cords.

CONCLUSIONS

This study presents a physical, clinical metric of spinal cord tension. Strong agreement among computational, cadaveric, and clinical studies demonstrates the utility of ultrasound-induced SWV for quantitative intraoperative feedback. This technology is positioned to enhance tethered cord diagnosis, treatment, and postoperative monitoring as it differentiates stretched from healthy cords.

Recommendations for neuroradiological examinations in children living with achondroplasia: a European Society of Pediatric Radiology and European Society of Neuroradiology opinion paper

Children living with achondroplasia are at an increased risk of developing neurological complications, which may be associated with acute and life-altering events. To remediate this risk, the timely acquisition of effective neuroimaging that can help to guide clinical management is essential. We propose imaging protocols and follow-up strategies for evaluating the neuroanatomy of these children and to effectively identify potential neurological complications, including compression at the cervicomedullary junction secondary to foramen magnum stenosis, spinal deformity and spinal canal stenosis. When compiling these recommendations, emphasis has been placed on reducing scan times and avoiding unnecessary radiation exposure. Standardized imaging protocols are important to ensure that clinically useful neuroimaging is performed in children living with achondroplasia and to ensure reproducibility in future clinical trials. The members of the European Society of Pediatric Radiology (ESPR) Neuroradiology Taskforce and European Society of Neuroradiology pediatric subcommittee, together with clinicians and surgeons with specific expertise in achondroplasia, wrote this opinion paper. The research committee of the ESPR also endorsed the final draft. The rationale for these recommendations is based on currently available literature, supplemented by best practice opinion from radiologists and clinicians with subject-specific expertise.

Development of a Machine Learning-Based Model for Accurate Detection and Classification of Cervical Spine Fractures Using CT Imaging

Cervical spine fractures represent a significant healthcare challenge, necessitating accurate detection for appropriate management and improved patient outcomes. This study aims to develop a machine learning-based model utilizing a computed tomography (CT) image dataset to detect and classify cervical spine fractures. Leveraging a large dataset of 4,050 CT images obtained from the Radiological Society of North America (RSNA) Cervical Spine Fracture dataset, we evaluate the potential of machine learning and deep learning algorithms in achieving accurate and reliable cervical spine fracture detection. The model demonstrates outstanding performance, achieving an average precision of 1 and 100% precision, recall, sensitivity, specificity, and accuracy values. These exceptional results highlight the potential of machine learning algorithms to enhance clinical decision-making and facilitate prompt treatment initiation for cervical spine fractures. However, further research and validation efforts are warranted to assess the model's generalizability across diverse populations and real-world clinical settings, ultimately contributing to improved patient outcomes in cervical spine fracture cases.

Beyond Pain Relief: An In-Depth Review of Vertebral Height Restoration After Balloon Kyphoplasty in Vertebral Compression Fractures

This comprehensive review delves into the intricate landscape of vertebral height restoration after balloon kyphoplasty in cases of vertebral compression fractures. With a comprehensive examination of procedural intricacies, radiological evaluations, clinical outcomes, and influential factors, a nuanced comprehension unfolds. Beyond its immediate alleviation of pain, vertebral height restoration emerges as a linchpin in enhancing spinal alignment, fostering functional recuperation, and augmenting the overall quality of life. This review underscores the pivotal role of balloon kyphoplasty, transcending its mere medical utility to become a conduit for renewed independence and well-being among individuals grappling with vertebral compression fractures. The ongoing advancements in medical science and the continued pursuit of research stand poised to amplify the significance of vertebral height restoration, manifesting a promising horizon for individuals seeking respite from pain, a revitalised capacity for movement, and a life unburdened by its constraints.

The Role of Magnetic Resonance Imaging and Computed Tomography in Spinal Cord Injury

Traumatic injuries of the spine are associated with long-term morbidity and mortality. Timely diagnosis and appropriate management of mechanical instability and spinal cord injury are important to prevent further neurologic deterioration. Spine surgeons require an understanding of the essential imaging techniques concerning the diagnosis, management, and prognosis of spinal cord injury. We present a review in the role of computed tomography (CT) including advancements in multidetector CT (MDCT), dual energy CT (DECT), and photon counting CT, and how it relates to spinal trauma. We also review magnetic resonance imaging (MRI) and some of the developed MRI based classifications for prognosticating the severity and outcome of spinal cord injury, such as diffusion weighted imaging (DWI), diffusion tractography (DTI), functional MRI (fMRI), and perfusion MRI.

Machine learning in clinical diagnosis, prognostication, and management of acute traumatic spinal cord injury (SCI): A systematic review

Background

Machine learning has been applied to improve diagnosis and prognostication of acute traumatic spinal cord injury. We investigate potential for clinical integration of machine learning in this patient population to navigate variability in injury and recovery.

Materials and methods

We performed a systematic review using PRISMA guidelines through PubMed database to identify studies that use machine learning algorithms for clinical application toward improvements in diagnosis, management, and predictive modeling.

Results

Of the 132 records identified, a total of 13 articles met inclusion criteria and were included in final analysis. Of the 13 articles, 5 focused on diagnostic accuracy and 8 were related to prognostication or management of traumatic spinal cord injury. Across studies, 1983 patients with spinal cord injury were evaluated with most classifying as ASIA C or D. Retrospective designs were used in 10 of 13 studies and 3 were prospective. Studies focused on MRI evaluation and segmentation for diagnostic accuracy and prognostication, investigation of mean arterial pressure in acute care and intraoperative settings, prediction of ambulatory and functional ability, chronic complication prevention, and psychological quality of life assessments. Decision tree, random forests (RF), support vector machines (SVM), hierarchical cluster tree analysis (HCTA), artificial neural networks (ANN), convolutional neural networks (CNN) machine learning subtypes were used.

Conclusions

Machine learning represents a platform technology with clinical application in traumatic spinal cord injury diagnosis, prognostication, management, rehabilitation, and risk prevention of chronic complications and mental illness. SVM models showed improved accuracy when compared to other ML subtypes surveyed. Inherent variability across patients with SCI offers unique opportunity for ML and personalized medicine to drive desired outcomes and assess risks in this patient population.

Degenerative Cervical Myelopathy: A Practical Approach to Diagnosis

STUDY DESIGN

Narrative Review.

OBJECTIVES

The objective of this review is to provide a stepwise approach to the assessment of patients with potential symptoms of degenerative cervical myelopathy (DCM).

METHODS

N/A.

RESULTS

DCM is an overarching term used to describe progressive compression of the cervical spinal cord by age-related changes to the spinal axis. These alterations to normal anatomy narrow the spinal canal, reduce the space available for the spinal cord, and may ultimately compress the ascending and descending neural tracts. Patients with DCM present with a wide range of symptoms that can significantly impact quality of life, including bilateral hand numbness and paresthesia, gait impairment, motor weakness of the upper and lower extremities, and bladder and bowel dysfunction. Unfortunately, DCM is often misdiagnosed, resulting in delayed assessment and management by the appropriate specialist. The proper evaluation of a patient with suspected DCM includes obtaining a detailed patient history, conducting a comprehensive neurological examination, and ordering appropriate tests to rule in or out other diagnoses.

CONCLUSION

This review summarizes a stepwise approach to the diagnosis of patients with DCM.

Aortic Impingement in Displaced Traumatic Spine Fracture with Complete Spinal Cord Transection: A Case Report

Aortic impingement associated with traumatic thoracic spinal fractures is a rare and potentially lethal complication that creates management challenges in an already complex clinical problem. Traumatic aortic injury is one of the leading causes of death in blunt trauma. Magerl divided thoracic and lumbar fractures into 3 categories; the primary focus of this report, type C fractures, describes rotational injury and is one of the less common types, especially associated with aortic impingement as such. In this case, a young man was admitted following a near-fatal fall resulting in blunt force trauma to the midthoracic region. Emergency CT revealed a type C complete transection at the level of T11 and a grade I aortic injury. Definitive fixation of the spinal injury was delayed in favor of preventing further vascular injury by prioritizing the securing of hemodynamic stability. In traumatic thoracolumbar injuries, blunt traumatic aortic injury is often managed conservatively. However, blunt thoracic aortic injury is one of the leading causes of death from trauma, and each case requires its own case-by-case multidisciplinary management. In this occasion, management of the vascular insult was paramount to ensuring patient survival and favorable outcome.

Vertebrae, IVD and spinal canal boundary extraction on MRI, utilizing CT-trained active shape models

PURPOSE

Vertebrae, intervertebral disc (IVD) and spinal canal (SC) displacements are in the root of several spinal cord pathologies. The localization and boundary extraction of these structures, along with the quantification of their displacements, provide valuable clues for assessing each pathological condition. In this work, we propose a computational method for boundary extraction of vertebrae, IVD and SC in magnetic resonance images (MRI).

METHOD

Vertebrae shape priors derived from computed tomography (CT) images are used to guide vertebrae, IVD and SC boundary extraction in MRI. This strategy is dictated by three considerations: (1) CT is the modality of choice for highlighting solid structures such as vertebrae, (2) vertebrae boundaries indirectly impose constraints on the boundaries of neighbouring structures (IVD and SC), and (3) it can be observed that edges are similarly located in CT and MR images; therefore, gradient profiles and shape priors learned by active shape models (ASMs) from CT are also valid in MRI.

RESULTS

Experimental comparisons on two MR image datasets demonstrate that the proposed approach obtains segmentation results, which are comparable to the state of the art. Moreover, the adopted bimodal strategy is validated by demonstrating that CT-derived shape priors lead to more accurate boundary extraction than MRI-derived shape priors, even in the case of MR image applications.

CONCLUSION

Unlike existing bimodal methods, the proposed one is not dependent on the availability of CT/MR image pairs, which are not usually acquired from the same patient. In addition, unlike state-of-the-art deep learning-based methods, it is not dependent on large amounts of training data. The proposed method requires a limited amount of user intervention.

Nanoparticles in traumatic spinal cord injury: therapy and diagnosis

Nanotechnology has been previously employed for constructing drug delivery vehicles, biosensors, solar cells, lubricants and as antimicrobial agents. The advancement in synthesis procedure makes it possible to formulate nanoparticles (NPs) with precise control over physico-chemical and optical properties that are desired for specific clinical or biological applications. The surface modification technology has further added impetus to the specific applications of NPs by providing them with desirable characteristics. Hence, nanotechnology is of paramount importance in numerous biomedical and industrial applications due to their biocompatibility and stability even in harsh environments. Traumatic spinal cord injuries (TSCIs) are one of the major traumatic injuries that are commonly associated with severe consequences to the patient that may reach to the point of paralysis. Several processes occurring at a biochemical level which exacerbate the injury may be targeted using nanotechnology. This review discusses possible nanotechnology-based approaches for the diagnosis and therapy of TSCI, which have a bright future in clinical practice.

Whole body measurements using near-infrared spectroscopy in a rat spinal cord contusion injury model

BACKGROUND

Spinal cord injuries cause great damage to the central nervous system as well as the peripheral vasculature. While treatments for spinal cord injury typically focus on the spine itself, improvements in the function of the peripheral vasculature after spinal cord injury have shown to improve overall neurological recovery.

OBJECTIVE

This study focused on the use of near-infrared spectroscopy (NIRS) as a mode to monitor cerebral and peripheral vascular condition non-invasively during the recovery process.

DESIGN

Animal research study.

METHODS

Rats underwent spinal contusion or sham injury and relative concentrations of de-/oxyhemoglobin (Δ[HbO]/Δ[Hb]) over time were measured over the cerebral, spinal, and pedal regions via NIRS. Correlational relationships across the body were determined. Rats received 1 NIRS measurement before injury and 3 after injury: 4, 7, and 14 days post.

RESULTS

Correlational relationships between signals across the body, between animals with and without spinal cord injury, indicate that NIRS was able to detect patterns of vascular change in the spine and the periphery occurring secondary to spinal cord injury and evolving during subsequent recovery. Additionally, NIRS determined an overall correlational decrease within the central nervous system, between spinal and cerebral measurements.

CONCLUSION

NIRS was able to closely reflect physiologic changes in the rat during recovery, demonstrating a promising method to monitor whole body hemodynamics after spinal cord injury.

Whole-body magnetic resonance imaging: technique, guidelines and key applications

Whole-body magnetic resonance imaging (WB-MRI) is an imaging method without ionising radiation that can provide WB coverage with a core protocol of essential imaging contrasts in less than 40 minutes, and it can be complemented with sequences to evaluate specific body regions as needed. In many cases, WB-MRI surpasses bone scintigraphy and computed tomography in detecting and characterising lesions, evaluating their response to therapy and in screening of high-risk patients. Consequently, international guidelines now recommend the use of WB-MRI in the management of patients with multiple myeloma, prostate cancer, melanoma and individuals with certain cancer predisposition syndromes. The use of WB-MRI is also growing for metastatic breast cancer, ovarian cancer and lymphoma as well as for cancer screening amongst the general population. In light of the increasing interest from clinicians and patients in WB-MRI as a radiation-free technique for guiding the management of cancer and for cancer screening, we review its technical basis, current international guidelines for its use and key applications.

Nonmissile penetrating spinal injuries: Mechanisms, expectations, and management

Background:

Nonmissile penetrating spinal injury (NMPSI) is an uncommon form of traumatic injury to the spine. Here, we present a comprehensive and contemporary literature review that provides insight into NMPSI-type injuries, their mechanisms, clinical practice, management, and expectations.

Methods:

An extensive review of the published literature was conducted in PubMed, OVID Medline, and EMBASE journals for studies of nonmissile penetrating spine injuries. Terms for search included NMPSI and nonmissile penetrating spinal cord injury. No date restrictions were used.

Results:

The search yielded only 17 related articles. Cross-checking of articles was conducted to exclude duplicate articles. The 17 articles were screened for their full text and English language availability. We finalized those articles pertaining to the topic.

Conclusion:

The mechanism of injury in NMPSI occurs in two different stages. Immediate injury is caused by direct damage to the neurological structures. The delayed injury response is caused by damage to the spinal vasculature and activated immune response pathways. Computed tomography (CT) angiograms or formal diagnostic angiograms are indicated to identify vascular injury or development of pseudoaneurysm and can be performed both preoperatively and postoperatively. Surgically, decompressive procedures include laminectomies and hemilaminectomies. Dural exploration may be indicated if a cerebrospinal fluid leak with fistula develops from dural puncture. Further research and technologies are being developed to provide patients who have suffered NMPSI with more resources for a better quality of life.

Imaging of the Spine: A Bibliometric Analysis of the 100 Most-Cited Articles

STUDY DESIGN

A bibliometric review of the literature.

OBJECTIVE

The aim of this study was to identify the most highly cited articles relating to imaging of the spine and to analyze the most influential papers and evolving trends in spinal imaging research.

SUMMARY OF BACKGROUND DATA

Spinal imaging is being performed with increasing frequency and is an essential step in the diagnosis and treatment planning of spinal pathology. A comprehensive review of the most influential articles in spinal imaging has not been performed, until now.

METHODS

A selection of search terms and keywords were inputted into the "Web of Science" database and the most highly cited articles in spinal imaging were selected from high impact factor journals. The top 100 articles were analyzed for year of publication, authorship, publishing journals, institution and country of origin, subject matter, article type, and level of evidence. In addition to total citation count, the number of annual citations was also calculated. Citation counts from Scopus and Google Scholar were also obtained for comparison across other citation index platforms.

RESULTS

The most highly cited articles in spinal imaging were published over 30 years, between 1983 and 2013. Total citation count ranged from 98 to 1243 with annual citation count ranging from 3.8 to 91.8. The greatest number of highly cited articles was produced in the United States (n = 49), involved magnetic resonance (n = 73) or multimodal (n = 17) imaging and focused on the lumbar spine (n = 42). The journals that contributed the most articles were Spine and Radiology each publishing 26 articles.

CONCLUSION

Our study provided an extensive list of the most historically significant spinal imaging articles, acknowledging the key contributions made to the advancement of this specialist field.

LEVEL OF EVIDENCE

5.

Radiological protocol in spinal trauma: literature review and Spinal Cord Society position statement

PURPOSE

The Spinal Cord Society constituted a panel tasked with reviewing the literature on the radiological evaluation of spinal trauma with or without spinal cord injury and recommend a protocol. This position statement provides recommendations for the use of each modality, i.e., radiographs (X-rays), computed tomography (CT), magnetic resonance imaging (MRI), as well as vascular imaging, and makes suggestions on identifying or clearing spinal injury in trauma patients.

METHODS

PubMed was searched for the corresponding keywords from January 1, 1980, to August 1, 2017. A MEDLINE search was subsequently undertaken after applying MeSH filters. Appropriate cross-references were retrieved. Out of the 545 articles retrieved, 105 relevant papers that address the present topic were studied and the extracted content was circulated for further discussions. A draft position statement was compiled and circulated among the panel members via e-mail. The draft was modified by incorporating relevant suggestions to reach a consensus.

RESULTS AND CONCLUSION

For imaging cervical and thoracolumbar spine trauma patients, CT without contrast is generally considered to be the initial line of imaging and radiographs are required if CT is unavailable or unaffordable. CT screening in polytrauma cases is best done with a multidetector CT by utilizing the reformatted images obtained when scanning the chest, abdomen, and pelvis (CT-CAP). MRI is indicated in cases with neurological involvement and advanced cervical degenerative changes and to determine the extent of soft tissue injury, i.e., disco-ligamentous injuries as well as epidural space compromise. MRI is also usually performed when X-rays and CT are unable to correlate with patient symptomatology. These slides can be retrieved under Electronic Supplementary Material.

Epidemiology of non-traumatic spinal cord injury in Uganda: a single center, prospective study with MRI evaluation

BACKGROUND

A few reliable national data concerning the etiology of non-traumatic spinal cord injury (SCI) in sub-Sahara Africa exists, mainly because of the limitations of diagnostic imaging. These are both expensive and mostly unavailable in several resource-limited settings. Only a few studies have employed the magnetic resonance imaging (MRI) in documenting non-traumatic SCI and most of these studies are from South Africa. We sought to describe the clinical presentation, MRI radiological patterns, and one-year survival among subjects with non-traumatic SCI in Uganda.

METHODS

We enrolled a prospective cohort of 103 participants with non-traumatic SCI at Mulago National Referral Hospital Kampala, Uganda in 2013-2015. Participants received standard of care management, with surgical intervention as needed, with one-year follow up. Data were analyzed using Descriptive statistics.

RESULTS

In 103 participants with non-traumatic SCI, the median (IQR) age was 37 (18, 85) years and 25% of the participants were HIV-infected. Paraplegia/paraparesis was the most common clinical presentation in 70% (n = 72). Severe disease was present in 82% (n = 85) as per American Spinal Injury Association (ASIA) scale A-C. On MRI, 50% had extradural lesions. However, bone lesions accounted for only 75% of all the extradural lesions. More than 60% of the patients had lesions that could only be diagnosed on MRI. Deaths occurred in 42% (n = 44) of participants, with the highest mortality among those with extradural lesions (60%).

CONCLUSION

The mortality following non-traumatic spinal cord injuries in Uganda is high. We demonstrated an equal distribution between extradural and intradural lesions, which differs from the historical predominance of extradural lesions. Increased utilization of MRI particularly among young age groups is needed to make a diagnosis.

Retained Glass Fragment in the Cervical Spinal Canal in a Patient with Acute Transverse Myelitis: A Case Report and Literature Review

A 50-year-old male presented with a one-day history of right leg weakness, numbness, and urinary retention. Weakness was present for two weeks but worsened significantly during the last 24 hours. On the right there was sensory loss in the leg and below the Th8 dermatome. On the left there was sensory loss below the Th10 dermatome and distal loss of temperature sensation. Past medical history revealed a cervical trauma 30 years ago when a glass chip lodged into the left side of the neck. The patient did not seek medical attention after removing it himself. No neurological symptoms followed the incident. No cervical manipulation or other physical trauma occurred before current symptom onset. Magnetic resonance (MR) imaging showed features consistent with myelitis at the level of C4–Th3. At the level of C6–C7, a T1 and T2 hypointense lesion was noted. On computed tomography, this lesion was hyperdense and occupied the spinal canal and the left intervertebral foramen. It was deemed to be a glass fragment. Surgical removal was withheld because the fragment was clinically silent for 30 years, the risk of surgical removal would outweigh the benefits and the patient did not prefer surgical treatment. Acute demyelinating transverse myelitis was diagnosed and treated with methylprednisolone. 10 months later MR features of myelitis resolved and the patient's neurological condition improved. Our case shows that foreign bodies in the cervical spinal canal can remain asymptomatic for up to 30 years. In the case of a long asymptomatic retention period the need for surgical removal of a foreign body must be carefully evaluated, taking into account the probability that a foreign body is the cause of current symptoms, risk of a foreign body causing damage in the future, risk of damage to the spinal cord during removal, and probability of therapeutic success.

MANF attenuates neuronal apoptosis and promotes behavioral recovery via Akt/MDM-2/p53 pathway after traumatic spinal cord injury in rats

The aim of this study was to investigate the potential effect and mechanism of action of MANF in attenuating neuronal apoptosis following t-SCI. A clip compressive model was used to induce a crush injury of the spinal cord in a total of 230 rats. The Basso, Beattie, and Bresnahan (BBB) score, spinal cord water content, and blood spinal cord barrier (BSCB) permeability were evaluated. The expression levels of MANF and its downstream proteins were examined by western blotting. Immunofluorescence staining of MANF, NeuN, GFAP, Iba-1, cleaved caspase-3, and TUNEL staining were also performed. Cells were counted in six randomly selected fields in the gray matter regions of the sections from two spinal cord sites (2 mm rostral and caudal to the epicenter of the injury) per sample. A cell-based mechanical injury model was also conducted using SH-SY5Y cells. Cell apoptosis and viability were assessed by flow cytometry, an MTT assay, and trypan blue staining. Subcellular structures were observed by transmission electron microscopy. MANF was mainly expressed in neurons. The expression levels of MANF, and its downstream target, p-Akt, were gradually increased and after t-SCI. Treatment with MANF increased Bcl-2 and decreased Bax and CC-3 levels; these effects were reversed on treatment with MK2206. The BBB score, spinal cord water content, and BSCB destruction were also ameliorated by MANF treatment. MANF decreases neuronal apoptosis and improves neurological function through Akt/MDM-2/p53 pathway after t-SCI. Therefore, MANF might be a potential treatment for patients with t-SCI.© 2018 BioFactors, 2018.

Role of CT scan in theranostic and management of traumatic spinal cord injury

Traumatic spinal cord injury (TSCI) is a condition with suffering of neural structures from acute trauma with short-term or permanent sensory and motor problems. This study was conducted with the aim of determining the prevalence of TSCI in Tehran with emphasis on demographic characteristics of patients and to evaluate the effect of computed tomography (CT) in determining fracture type and severity grade of injury among TSCI patients. In a cross-sectional study, all TSCI and spinal fracture patients (N = 520) who referred to the main trauma center in Tehran, Iran, in 2013 and 2014 were selected. Radiography and CT scan were prepared and reported blindedly by two radiologists. Majority of the patients was 21-30 years male, married and their most common occupation was car driver. A significant difference was observed between gender and etiology (P = 0.001). The main etiology was traffic accident followed by falling from height. While the most common location of injury for males was thoracic vertebrae followed by lumbar vertebrae; for females it was lumbar followed by thoracic. Majority of patients had ASIA (American Spinal Injury Association) impairment scale of E (normal), followed by B (sensory incomplete). Most of the cases were hospitalized less than one week. Age of the patient and duration of hospitalization had a significant association (P = 0.015). The results showed that in traumatic spinal cord events, traffic accident and falling from height are the main etiologies; hence, authorities in Iranian health system could consider preventive policies to decline the load and TSCI effects in hospitals and population.

A study of predictors for hyponatraemia in patients with cervical spinal cord injury

STUDY DESIGN

A retrospective study.

OBJECTIVES

The objectives of the study were to investigate the predictors for hyponatraemia in patients with cervical spinal cord injuries (CSCIs) and to define the relationship between magnetic resonance imaging (MRI) scans and hyponatraemia.

SETTING

The study was carried out at The First Affiliated Hospital of Anhui Medical University.

METHODS

A total of 292 patients with CSCIs were retrospectively reviewed to determine the predictors of hyponatraemia. Fourteen variables were extracted from the medical records: age, sex, blood pressure (BP), tracheostomy, serum potassium, serum chloride, serum bicarbonate, serum albumin, intravenous fluid intake and urine volume for 24 h, haematocrit, haemoglobin, neurological assessment and four MRI signal patterns. Univariate and multivariate analyses were used to determine the effect of each variable on hyponatraemia.

RESULTS

Eighty-two of the 270 patients (30%) developed hyponatraemia. Univariate analyses indicated that the following variables were significant predictors of hyponatraemia: tracheostomy; the initial American Spinal Injury Association (ASIA) Impairment Scale (AIS) A assessment; and haemorrhage changes on T2-weighted MRI scans, and low BP. Multivariate regression analyses revealed two variables were significant predictors of hyponatraemia: haemorrhage changes on T2-weighted MRI scans and low BP.

CONCLUSIONS

Haemorrhage changes on MRI scans were closely associated with the onset of hyponatremia and could provide objective data for forecasting hyponatraemia in CSCI patients. Low BP was also a reasonable predictor of hyponatremia.

Myelopathy

Myelopathy is an inclusive term, referring to pathology leading to a neurologic deficit related to the spinal cord. The clinical diagnosis of myelopathy requires a detailed history and physical examination to define the clinical syndrome. Neuroimaging is indicated in most instances of new-onset myelopathy. It is indicated also when the worsening of a myelopathy is unexplained. Advances in neuroimaging have proved to play a vital role in diagnosis. Appropriate diagnosis and treatment are dependent upon an adequate imaging evaluation to establish the presence of mechanical stability, extrinsic spinal cord compression, or an intramedullary lesion. The most frequent etiology of myelopathy is related to degenerative disease of the spine from osteophyte or extruded disc material causing compression of the spinal cord in the cervical or thoracic spine. The next common etiologies are spinal cord compression due to extradural masses caused by metastatic disease to bone or blunt trauma. In these cases, emergency imaging should be performed to assess the nature of the lesion causing the myelopathy and plan the most appropriate treatment. Also urgent imaging should be performed when an abscess in the spinal canal is suspected. Less urgent is imaging of primary neoplasms of the meninges, roots, or spinal cord, as well as noninfectious inflammatory processes, such as multiple sclerosis, and neurodegenerative, vascular, nutritional, or idiopathic disorders leading to myelopathy. Although a survey of the entire spinal cord can be performed with imaging, it is more appropriate to define from the clinical findings what levels of the spine and spinal cord should be imaged. This approach helps limit the likelihood of false-positive imaging findings that may encourage needless attempts to fix what is not broken. Similarly, the most appropriate imaging study and protocol should be selected in order to provide a timely and accurate diagnosis. To do so requires detailed knowledge regarding the strengths and limitations of the multiple imaging modalities available. This chapter outlines an approach to proper study selection based on the likely etiology of myelopathy from the clinical findings. Chapters 33-39 cover these disorders in detail.

Magnetic resonance imaging tractography as a diagnostic tool in patients with spinal cord injury treated with human embryonic stem cells

Introduction Spinal cord injury is a cause of severe disability and mortality. The pharmacological and non-pharmacological methods used, are unable to improve the quality of life in spinal cord injury. Spinal disorders have been treated with human embryonic stem cells. Magnetic resonance imaging and tractography were used as imaging modality to document the changes in the damaged cord, but the magnetic resonance imaging tractography was seen to be more sensitive in detecting the changes in the spinal cord. The present study was conducted to evaluate the diagnostic modality of magnetic resonance imaging tractography to determine the efficacy of human embryonic stem cells in chronic spinal cord injury. Materials and methods The study included the patients with spinal cord injury for whom magnetic resonance imaging tractography was performed before and after the therapy. Omniscan (gadodiamide) magnetic resonance imaging tractography was analyzed to assess the spinal defects and the improvement by human embryonic stem cell treatment. The patients were also scored by American Spinal Injury Association scale. Results Overall, 15 patients aged 15-44 years with clinical manifestations of spinal cord injury had magnetic resonance imaging tractography performed. The average treatment period was nine months. The majority of subjects ( n = 13) had American Spinal Injury Association score A, and two patients were at score C at the beginning of therapy. At the end of therapy, 10 patients were at score A, two patients were at score B and three patients were at score C. Improvements in patients were clearly understood through magnetic resonance imaging tractography as well as in clinical signs and symptoms. Conclusion Magnetic resonance imaging tractography can be a crucial diagnostic modality to assess the improvement in spinal cord injury patients.

Effect of lycopene on the blood-spinal cord barrier after spinal cord injury in mice

The current study aimed to investigate the effect of lycopene on the blood-spinal cord barrier (BSCB) after spinal cord injury (SCI) in a mouse model. Lycopene inhibited lipid peroxidation and oxidative DNA damage as a highly efficient antioxidant and free radical scavenger. Lycopene (4 mg/kg/d) was administrated immediately following SCI. The permeability of the BSCB and water content in the spinal cord tissue were evaluated. Additionally, levels of expression of tight junction proteins and heme oxygenase-1 (HO-1) were determined with Western blotting. An enzyme-linked immunosorbent assay analysis of spinal cord tissue homogenates was performed 48 h after SCI to evaluate the expression of inflammation-related cytokines. In addition, recovery of motor function was assessed 1 d, 2 d, 5 d, 10 d, and 15 d after SCI using the Basso Mouse Scale to score locomotion. Compared to the group with an untreated SCI, mice with an SCI treated with lycopene had significantly reduced spinal cord tissue water content and BSCB permeability. Furthermore, motor function of mice with an SCI was also greatly improved by lycopene administration. The expression of the proinflammatory factors TNF-α and NF-kB increased markedly 48 h after SCI, and their upregulation was significantly attenuated by lycopene treatment. The expression of molecules that protect tight junctions, zonula occluden-1 and claudin-5, was upregulated by lycopene treatment after SCI. Taken together, these results clearly indicate that lycopene attenuated SCI by promoting repair of the damaged BSCB, so lycopene is a novel and promising treatment for SCI in humans.

Thoracic spine trauma: advanced imaging modality

Technological advances in diagnostic imaging make the diagnosis of spinal trauma more accurate both in the acute and in the chronic settings. Improvements in medical care and in diagnostic imaging lead to an increasing prevalence of patients' surviving injuries. The management of these patients depends on early and appropriate radiological evaluation in the acute phase. The aim of this work was to review advanced imaging modalities employed to study thoracic spine and spinal cord in injured patients.

Large animal models of human cauda equina injury and repair: evaluation of a novel goat model

Previous animal studies of cauda equina injury have primarily used rat models, which display significant differences from humans. Furthermore, most studies have focused on electrophysiological examination. To better mimic the outcome after surgical repair of cauda equina injury, a novel animal model was established in the goat. Electrophysiological, histological and magnetic resonance imaging methods were used to evaluate the morphological and functional outcome after cauda equina injury and end-to-end suture. Our results demonstrate successful establishment of the goat experimental model of cauda equina injury. This novel model can provide detailed information on the nerve regenerative process following surgical repair of cauda equina injury.

Marrow edema variability in acute spine fractures

BACKGROUND CONTEXT

The presence or absence of marrow edema is used in the assessment of fracture acuity in magnetic resonance imaging (MRI). We have observed variability in the degree of marrow edema in acute trauma. Our aim was to characterize the utility of marrow edema in fracture detection and fracture acuity on MRI. We hypothesized that only vertebral body compression injuries reliably generate marrow edema and that distraction injuries or fractures without compression do not reliably generate marrow edema and may give a false negative MRI examination.

PURPOSE

To characterize the utility of marrow edema in fracture detection and fracture acuity on MRI.

STUDY DESIGN

Two-year single-center retrospective review of marrow edema in patients evaluated by both computed tomography (CT) and MRI in acute trauma setting.

PATIENT SAMPLE

The final study cohort consisted of 163 patients (mean age, 54.5 years; standard deviation, 23.5 years; range, 8-94 years; 85 men and 78 women).

OUTCOME MEASURES

A physiologic measure of marrow edema as assessed by T2-signal hyperintensity on short tau inversion recovery sequence MRI examination.

METHODS

After institutional review board approval, we conducted a retrospective review of 1,215 patients who were evaluated at our hospital for suspected spine trauma with a combination of CT and MRI. Patients were assessed for fracture presence, location, type, and absence or degree of marrow edema.

RESULTS

The investigation identified 189/1,215 patients who had acute fractures on CT, subsequently imaged within 48 hours by MRI. A total of 94/288 acute fractures did not generate marrow edema. There were 63 patients (83 acute fractures) whose mechanism of injury resulted exclusively in acute fractures with no marrow edema. A statistically significant difference in marrow edema was observed with acute vertebral body compression fractures compared with acute fractures with distraction or fractures without compression. Moreover, certain fracture types were identified that often generate little or no marrow edema in acute trauma setting.

CONCLUSIONS

There is variability in the presence or degree of marrow edema on MRI evaluation after traumatic injury. Only fractures derived from vertebral body compression reliably generate marrow edema. Fractures without compression and/or fractures with distraction do not reliably generate marrow edema and can lead to a false negative MRI. An awareness of fracture types that produce more or less marrow edema can be beneficial when evaluating fractures by MRI.

Melatonin treatment protects against acute spinal cord injury-induced disruption of blood spinal cord barrier in mice

The spinal cord microcirculation plays a critically important role in maintaining the normal function of spinal cord neurons, glial cells, and axons. Previous researches were largely focused on improved neurological manifestations of spinal cord injury (SCI) while ignoring to improve spinal cord microcirculation disorder after melatonin treatment. Therefore, the mechanism of melatonin that affects blood spinal cord barrier (BSCB) integrity and microcirculation in SCI remains unclear. The present study was performed to investigate the effect of melatonin on the BSCB in a SCI mice model. Melatonin (5, 10, 25, 50, 100 mg/kg i.p.) was administered to mice immediately following SCI. Compared to the 48 h post-SCI group, mice treated with melatonin (50 mg/kg) exhibited significantly reduced BSCB permeability. Additionally, melatonin treatment restrained microvessel loss; attenuated edema; protected the tight junction proteins, endothelial cells, and pericytes; decreased the number of cell apoptosis; and reduced MMP3/AQP4/HIF-1α/VEGF/VEGFR2 expression after SCI. Above all, our results clearly demonstrated that melatonin could stabilize microvascular barrier function and microcirculation of SCI, whose mechanism was to promote the repair of the damaged BSCB.

The reliability of red flags in spinal cord compression

Background:

Acute low back pain is a common cause for presentation to the emergency department (ED). Since benign etiologies account for 95% of cases, red flags are used to identify sinister causes that require prompt management.

Objectives:

We assessed the effectiveness of red flag signs used in the ED to identify spinal cord and cauda equine compression.

Patients and Methods:

It was a retrospective cohort study of 206 patients with acute back pain admitted from the ED. The presence or absence of the red flag symptoms was assessed against evidence of spinal cord or cauda equina compression on magnetic resonance imaging (MRI).

Results:

Overall, 32 (15.5%) patients had compression on MRI. Profound lower limb neurologic examination did not demonstrate a statistically significant association with this finding. The likelihood ratio (LR) for bowel and bladder dysfunction (sensitivity of 0.65 and specificity of 0.73) was 2.45. Saddle sensory disturbance (sensitivity of 0.27 and specificity of 0.87) had a LR of 2.11. When both symptoms were taken together (sensitivity of 0.27 and specificity of 0.92), they gave a LR of 3.46.

Conclusions:

The predictive value of the two statistically significant red flags only marginally raises the clinical suspicion of spinal cord or cauda equina compression. Effective risk stratification of patients presenting to the ED with acute back pain is crucial; however, this study did not support the use of these red flags in their current form.

The effect of cigarette smoke exposure on spinal cord injury in rats

In this study, we examined whether cigarette smoke has neuroprotective or toxic effects on spinal cord injury (SCI). Male Sprague-Dawley rats were included in the study and received either cigarette smoke exposure or fresh air exposure. Twenty-four hours after the last cigarette smoke or fresh air exposure, all rats were injured at thoracic level 12 (T12), using an established static compression model. Our data showed that the cigarette smoke group had higher water content; higher permeability of the blood-spinal cord barrier (BSCB); higher malondialdehyde (MDA) levels, aquaporin-4 (AQP4) and hypoxia-inducible factor 1-alpha (HIF-1α) protein expression, and mRNA levels; and lower glutathione (GSH) levels than the control group values at 12 h, 24 h, and 48 h after SCI. There was no significant difference in these between the cigarette smoke group and the control group at 0 h after SCI. The results of the Basso, Beattie, and Bresnahan (BBB) hindlimb locomotor rating scale showed that rats in the cigarette smoke group had greater dysfunction in hindlimb movement than did rats in control group from 2 to day 6 after SCI. The extent of recovery did not make any difference from day 7 to day 10 after SCI between the cigarette smoke group and the control group. These results suggested that cigarette smoke can reinforce the oxidative stress injury via HIF-1α and AQP4 in the early stage after SCI. It is possible that cigarette smoke exposure does not affect SCI recovery in the long term; however, it can aggravate the edema and deteriorate BSCB disruption via HIF-1α and AQP4 in the early stage after SCI. More studies will be essential to consider this hypothesis and elucidate the mechanisms involved.

Flexible image evaluation: iPad versus secondary-class monitors for review of MR spinal emergency cases, a comparative study

RATIONALE AND OBJECTIVES

Studies have highlighted the potential of handheld viewing devices for rapid diagnosis and increased smartphone usage among physicians and radiologists is known as is the clinical applicability of hand-held devices for computed tomography (CT) spinal injury cases. Magnetic resonance (MR), however, is the accepted gold standard for spinal imaging, providing visualization of both ligament and spinal cord pathology. This study investigated the diagnostic accuracy of the iPad, the most probable alternative display device outside the radiology environment and financially viable alternative, when reviewing emergency spinal MR images, in comparison with secondary-class LCD devices in the case of the interpretation of CT and MR imaging examinations.

MATERIALS AND METHODS

In total 31 MR cases including both positives (n = 13) containing one of four possible presentations: spinal cord compression, cauda equine syndrome, spinal cord hemorrhage, or spinal cord edema and controls (n = 18) were reviewed. Ziltron iPad software facilitated the display of cases and the receiver operating characteristic (ROC) analysis. Thirteen American Board of Radiology board-certified radiologists reviewed all cases on both displays. Standardized viewing conditions were maintained.

RESULTS

Dorfman-Berbaum-Metz multireader-multicase (DBM MRMC) analysis was performed including random readers/random cases, fixed readers/random cases and random readers/fixed cases. No differences of statistical significance (P ≤ .05) could be found in terms of area under the curve, sensitivity and specificity between the iPad and secondary-class display.

CONCLUSION

The iPad performed with equal diagnostic accuracy when compared with the secondary-class LCD device after DBM MRMC analysis, demonstrating the iPad as an option to aid initial review of MR spinal emergency cases.

Clinical review: Spinal imaging for the adult obtunded blunt trauma patient: update from 2004

PURPOSE

Controversy exists over how to 'clear' (we mean enable the clinician to safely remove spinal precautions based on imaging and/or clinical examination) the spine of significant unstable injury among clinically unevaluable obtunded blunt trauma patients (OBTPs). This review provides a clinically relevant update of the available evidence since our last review and practice recommendations in 2004.

METHODS

Medline, Embase. Google Scholar, BestBETs, the trip database, BMJ clinical evidence and the Cochrane library were searched. Bibliographies of relevant studies were reviewed.

RESULTS

Plain radiography has low sensitivity for detecting unstable spinal injuries in OBTPs whereas multidetector-row computerised tomography (MDCT) approaches 100%. Magnetic resonance imaging (MRI) is inferior to MDCT for detecting bony injury but superior for detecting soft tissue injury with a sensitivity approaching 100%, although 40% of such injuries may be stable and 'false positive'. For studies comparing MDCT with MRI for OBTPs; MRI following 'normal' CT may detect up to 7.5% missed injuries with an operative fixation in 0.29% and prolonged collar application in 4.3%. Increasing data is available on the complications associated with prolonged spinal immobilisation among a population where a minority have an actual injury.

CONCLUSIONS

Given the variability of screening performance it remains acceptable for clinicians to clear the spine of OBTPs using MDCT alone or MDCT followed by MRI, with implications to either approach. Ongoing research is needed and suggestions are made regarding this. It is essential clinicians and institutions audit their data to determine their likely screening performances in practice.

Comparative study of lumbar magnetic resonance imaging and myelography in young soldiers with herniated lumbar disc

OBJECTIVE

This study was undertaken to compare the diagnostic performances of magnetic resonance imaging (MRI), MR myelography (MRM) and myelography in young soldiers with a herniated lumbar disc (HLD).

METHODS

Sixty-five male soldiers with HLD comprised the study cohort. A visual analogue scale for low back pain (VAS-LBP), VAS for leg radiating pain (VAS-LP), and Oswestry disability index (ODI) were applied. Lumbar MR, MRM, and myelographic findings were checked and evaluated by four independent radiologists, respectively. Each radiologist was asked to score (1 to 5) the degree of disc protrusion and nerve root compression using modified grading systems devised by the North American Spine Society and Pfirrmann and the physical examination rules for conscription in the Republic of Korea. Correlated coefficients between clinical and radiological factors were calculated. Interpretational reproducibility between MRI and myelography by four bases were calculated and compared.

RESULTS

Mean patient age was 20.5 ± 1.1. Mean VAS-LBP and VAS-LP were 6.7 ± 1.6 and 7.4 ± 1.7, respectively. Mean ODI was 48.0 ± 16.2%. Mean MRI, MRM, and myelography scores were 3.3 ± 0.9, 3.5 ± 1.0, and 3.9 ± 1.1, respectively. All scores of diagnostic performances were significantly correlated (p < 0.05). However, none of these scores reflected the severity of patients' symptoms. There was no statistical difference of interpretational reproducibility between MRI and myelography.

CONCLUSION

Although MRI and myelography are based on different principles, they produce similar interpretational reproducibility in young soldiers with a HLD. However, these modalities do not reflect the severity of symptoms.

Mapping lipid alterations in traumatically injured rat spinal cord by desorption electrospray ionization imaging mass spectrometry

Desorption electrospray ionization (DESI) mass spectrometry (MS) is used in an imaging mode to interrogate the lipid profiles of 15 μm thin tissue cross sections of injured rat spinal cord and normal healthy tissue. Increased relative intensities of fatty acids, diacylglycerols, and lysolipids (between +120% and +240%) as well as a small decrease in intensities of lipids (-30%) were visualized in the lesion epicenter and adjacent areas after spinal cord injury. This indicates the hydrolysis of lipids during the demyelination process due to activation of phospholipase A(2) enzyme. In addition, signals corresponding to oxidative degradation products, such as prostaglandin and hydroxyeicosatetraenoic acid, exhibited increased signal intensity by a factor of 2 in the negative ion mode in lesions relative to the normal healthy tissue. Analysis of malondialdehyde, a product of lipid peroxidation and marker of oxidative stress, was accomplished in the ambient environment using reactive DESI mass spectrometry imaging. This was achieved by electrospraying reagent solution containing dinitrophenylhydrazine as high-velocity charged droplets onto the tissue section. The hydrazine reacts selectively and rapidly with the carbonyl groups of malondialdehyde, and signal intensity of twice the intensity was detected in the lesions compared to healthy spinal cord. With a small amount of tissue sample, DESI-MS imaging provides information on the composition and distribution of specific compounds (limited by the occurrence of isomeric lipids with very similar fragmentation patterns) in lesions after spinal cord injury in comparison with normal healthy tissue allowing identification of the extent of the lesion and its repair.

2-Methoxyestradiol inhibits the up-regulation of AQP4 and AQP1 expression after spinal cord injury

The study investigated the mechanism of the up-regulation of aquaporin-4 (AQP4) and aquaporin-1 (AQP1) expression induced by spinal cord injury (SCI). Using adult rat spinal cord injury model, it was found that up-regulation of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), AQP4, and AQP1 in response to spinal cord injury was greatly antagonized by 2-methoxyestradiol (2ME2), which can post-transcriptionally inhibit the expression of HIF-1α. VEGF alone significantly increased the extravasation of Evans blue and up-regulated the levels of AQP4 protein expression in the injured spinal cord issue, but the levels of AQP1 expression were not significantly changed. Taken together, our results suggest that expression of AQP4 and AQP1 is correlated with up-regulation of HIF-1α after SCI through the mechanisms that were dependent and independent of the VEGF signaling pathway, respectively. And the inhibitor of HIF-1α is a novel promising therapeutic agent for human SCI-induced edema in the future.