Restricted diffusion in spinal cord infarction demonstrated by magnetic resonance line scan diffusion imaging

Spontaneous spinal cord infarction: a systematic review

Background and objectives

Spontaneous spinal cord infarction (SCInf) is a rare condition resulting in acute neurological impairment. Consensus on diagnostic criteria is lacking, which may present a challenge for the physician. This review aims to analyse the current literature on spontaneous SCInf, focusing on epidemiology, the diagnostic process, treatment strategies and neurological outcomes.

Methods

The study was performed in accordance with a previously published protocol. PubMed, Web of Science and Embase were searched using the keywords 'spontaneous', 'spinal cord', 'infarction' and 'ischaemic'. The eligibility of studies was evaluated in two steps by multiple reviewers. Data from eligible studies were extracted and systematically analysed.

Results

440 patients from 33 studies were included in this systematic review. Analysis of vascular risk factors showed that hypertension was present in 40%, followed by smoking in 30%, dyslipidaemia in 29% and diabetes in 16%. The severity of symptoms at admission according to the American Spinal Injury Association (ASIA) Impairment Scale was score A 19%, score B14%, score C36% and score D32%. The mean follow-up period was 34.8 (±12.2) months. ASIA score at follow-up showed score A 11%, score B 3%, score C 16%, score D 67% and score E 2%. The overall mortality during the follow-up period was 5%. When used, MRI with diffusion-weighted imaging (DWI) supported the diagnosis in 81% of cases. At follow-up, 71% of the patients were able to walk with or without walking aids.

Conclusion

The findings suggest a significant role for vascular risk factors in the pathophysiology of spontaneous SCInf. In the diagnostic workup, the use of DWI along with an MRI may help in confirming the diagnosis. The findings at follow-up suggest that neurological recovery is to be expected, with the majority of patients regaining ambulation. This systematic review highlights gaps in the literature and underscores the necessity for further research to establish diagnostic criteria and treatment guidelines.

It Looks Like a Spinal Cord Tumor but It Is Not

Differentiating neoplastic from non-neoplastic spinal cord pathologies may be challenging due to overlapping clinical and radiological features. Spinal cord tumors, which comprise only 2-4% of central nervous system tumors, are rarer than non-tumoral myelopathies of inflammatory, vascular, or infectious origins. The risk of neurological deterioration and the high rate of false negatives or misdiagnoses associated with spinal cord biopsies require a cautious approach. Facing a spinal cord lesion, prioritizing more common non-surgical myelopathies in differential diagnoses is essential. A comprehensive radiological diagnostic approach is mandatory to identify spinal cord tumor mimics. The diagnostic process involves a multi-step approach: detecting lesions primarily using MRI techniques, precise localization of lesions, assessing lesion signal intensity characteristics, and searching for potentially associated anomalies at spinal cord and cerebral MRI. This review aims to delineate the radiological diagnostic approach for spinal cord lesions that may mimic tumors and briefly highlight the primary pathologies behind these lesions.

Posterior spinal artery infarct

Posterior spinal artery syndrome has a variable presentation and often poses a clinical challenge. We describe an acute posterior spinal artery syndrome in a man in his 60s with vascular risk factors, who presented with altered sensation in the left arm and left side of his torso but with normal tone, strength and deep tendon reflexes. MR imaging showed a left paracentral T2 hyperintense area affecting the posterior spinal cord at the level of C1. Diffusion-weighted MRI (DWI) showed high signal intensity in the same location. He was medically managed as having ischaemic stroke and made a good recovery. Three-month MRI follow-up showed a persisting T2 lesion but the DWI changes had resolved, consistent with the time course for infarction. Posterior spinal artery stroke has a variable presentation and is probably under-recognised clinically, requiring careful attention to MR imaging for its diagnosis.

Isolated Infarctions of the Conus Medullaris: Clinical Features and Outcomes

OBJECTIVE

This study aims to describe the clinical features and outcomes of patients with isolated infarctions of the conus medullaris, and to identify factors associated with poor functional outcomes.

MATERIALS AND METHODS

We performed a systematic review and retrospective analysis on the clinical characteristics and outcomes of patients with isolated conus medullaris infarctions reported in literature over the past 30 years.

RESULTS

We analyzed a total of 19 cases; 18 identified in literature from January 1991 to June 2021, together with our patient. Their median age was 56 years (range 28-79), with twice as many females as males. Pain was prominent at onset (15/19, 79%), only a third had vascular risk factors (7/19, 37%), and half had no significant preceding activities or events (9/19, 47%). Almost all experienced paraplegia or paraparesis (16/19, 84%), in which upper motor neuron features were rare (3/19, 16%). The underlying cause was unknown in half (10/19, 53%). Functional outcomes appeared fair, with nearly half being capable of unassisted ambulation (9/11, 82%). Patients with vascular risk factors (67% vs 13%, p = 0.024) or with identified underlying causes (78% vs 13%, p = 0.007) were less likely to walk unassisted.

CONCLUSION

Isolated conus medullaris but should be considered in patients with acute cauda equina syndrome, especially in females. Patients with vascular risk factors, or with known causes of infarction, are less likely to walk unassisted. DWI sequences should be included in conventional MRI sequences when evaluating patients with acute cauda equina syndrome.

A Curious Case of Progressive Respiratory Failure Due to Anterior Spinal Cord Infarction in an Adolescent Boy: A Case Report and Review of the Literature

Clinical features of cervical spontaneous spinal cord infarctions (SSCIs) remain poorly described in the literature. The goal of this article was to improve recognition of cervical SSCI, a rare but life-threatening condition. We presented a 15-year-old adolescent male patient who developed neck pain with weakness and numbness in all four limbs half an hour after returning from a hike in the late afternoon. The next morning, he was brought to the emergency room due to persistent weakness, vomiting, and progressive respiratory distress. He was promptly intubated for airway protection. Pupils were 2 mm, sluggishly reactive, and all four extremities were flaccid. He was found to have anterior spinal cord syndrome. Light touch (brush) was normal down to the posterior aspect of shoulders. Cervical magnetic resonance imaging (MRI) showed increased T2/short-tau inversion recovery and decreased T1 signal of the anterior spinal cord from C3 to C7. Four days later, MRI of the spinal cord showed restricted diffusion of anterior spinal cord consistent with radicular artery territory infarction. The work-ups for infection, thrombosis, and cardioembolism were all negative. Three months later, he still had incomplete Brown-Séquard's syndrome, as position sense was preserved. There was in addition bilateral loss of pain and temperature sensations below the clavicles. MRI showed cervical myelomalacia most severe between C3 and C5. Furthermore, MRI showed changes in C3–C4 intervertebral disc, consistent with a fibrocartilaginous embolism via retrograde arterial route into the anterior spinal artery. This article demonstrates the importance of recognizing subtle clinical clues leading to cervical SSCI diagnosis.

ACR Appropriateness Criteria® Myelopathy: 2021 Update

Myelopathy is a clinical diagnosis with localization of the neurological findings to the spinal cord, rather than the brain or the peripheral nervous system, and then to a particular segment of the spinal cord. Myelopathy can be the result of primary intrinsic disorders of the spinal cord or from secondary conditions, which result in extrinsic compression of the spinal cord. While the causes of myelopathy may be multiple, the acuity of presentation and symptom onset frame a practical approach to the differential diagnosis. Imaging plays a crucial role in the evaluation of myelopathy with MRI the preferred modality. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Sulcal artery syndrome: A Three-patient series and review of literature

OBJECTIVE

This study aims to describe the clinical characteristics of patients with sulcal artery syndrome, and between those with vertebral artery dissection against those without.

METHODS

We report three cases of sulcal artery syndrome without vertebral artery dissection, performed a systematic review and retrospective analysis of the characteristics of patients with sulcal artery syndrome in available literature, and compared the clinical features of those with vertebral artery dissection against those without.

RESULTS

We report 3 patients with sulcal artery syndrome, and analysed them with 17 other cases identified in literature between January 1990 till April 2020. The mean age was 47 years (range 10-80), with twice as many males as females. Pain at onset was a prominent feature (17/18, 94.4%). Preceding trauma occurred in less than half (7/18, 38.9%). Most had cervical cord infarctions (18/20, 90%), often over the high cervical cord (16/18, 88.9%). Good functional recovery (mRS 0-2) was observed in 86.7% (13/15). While vertebral artery dissection was the leading aetiology (11/20, 55.5%), about half of the cases were due to other causes. Cervical cord involvement was significantly associated with vertebral artery dissection (p = 0.026).

CONCLUSION

Sulcal artery syndrome should be suspected in patients with acute hemicord syndrome, especially in males with cervical cord involvement or pain at onset. High cervical cord involvement was strongly suggestive of underlying vertebral artery dissection. Additionally, DWI sequences are useful when evaluating acute myelopathies, and its inclusion in conventional MRI sequences is supported in prevailing literature.

Diffusion Tensor Imaging of the Spinal Cord

Spinal cord often is regarded as one of the last territories in the central nervous system where diffusion tensor imaging (DTI) can be used to probe white matter architecture. This article reviews current progress in spinal cord DTI, starting with anatomic properties and technical challenges that make spinal cord DTI a difficult task. Several possibilities offered by advanced pulse sequences that might overcome the difficulties are addressed, with associated trade-offs and limitations. Potential clinical assistance also is discussed in various spinal cord pathologies, such as myelopathy due to external compression, spinal cord tumors, acute ischemia, traumatic injury, and so forth.

Multimodal analysis of the effects of dexamethasone on high-altitude cerebral oedema: protocol for a pilot study

Background

Acute mountain sickness (AMS) is a cluster of symptoms that commonly occur in those ascending to high altitudes. Symptoms can include headaches, nausea, insomnia and fatigue. Exposure to high altitude can also lead to high-altitude cerebral oedema (HACE), which is a potential cause of death whilst mountaineering. Generally, AMS precedes the development of HACE. Historical studies have demonstrated the effectiveness of regular dexamethasone administration in reducing the symptoms of AMS. However, the mechanism by which dexamethasone works to reduce symptoms AMS remains poorly understood. Further studies, simulating altitude using hypoxic tents, have characterised the effect of prolonged exposure to normobaric hypoxia on cerebral oedema and blood flow using MRI. This randomised trial assesses the effect of dexamethasone on hypoxia-induced cerebral oedema in healthy adult volunteers.

Methods/design

D4H is a double-blind placebo-controlled randomised trial assessing the effect of dexamethasone on hypoxia-induced cerebral oedema. In total, 20 volunteers were randomised in pairs to receive either 8.25 mg dexamethasone or normal saline placebo intravenously after 8 h of hypoxia with an FiO₂ of 12%. Serial MRI images of the brain and spinal cord were obtained at hours 0, 7, 11, 22 and 26 of the study along with serum and urinary markers to correlate with the severity of cerebral oedema and the effect of the intervention.

Discussion

MRI has been used to identify changes in cerebral vasculature in the development of AMS and HACE. Dexamethasone is effective at reducing the symptoms of AMS; however, the mechanism of this effect is unknown. If this study demonstrates a clear objective benefit of dexamethasone in this setting, future studies may be able to demonstrate that dexamethasone is an effective therapy for oedema associated with brain and spinal cord ischaemia beyond AMS.

Trial registration

Clinicaltrials.gov, NCT03341676. Registered on 14 November 2017.

Acute ischemic myelopathy treated with intravenous thrombolysis: Four new cases and literature review

Background

Intravenous thrombolysis is a well-established treatment of ischemic stroke within 4.5 h. However, its effectiveness in acute ischemic myelopathy is unknown.

Purpose

We describe a series of four acute ischemic myelopathy patients treated with intravenous thrombolysis within 4.5 h and review the current literature to explore this treatment feasibility, potential safety, and efficacy.

Methods

We reviewed all routinely collected clinical, radiological, and follow-up data of patients with a final acute ischemic myelopathy diagnosis who received acute intravenous thrombolysis in our stroke network. We also reviewed thrombolyzed acute ischemic myelopathy patients in the literature.

Results

Four patients (three women) aged 57 to 83 years presented with acute uni- or bilateral extremity paresis, considered initially as cerebral strokes in two of them. After excluding contraindications by brain imaging in three, spinal computed tomography in one and confirmation of acute ischemic myelopathy on spinal magnetic resonance imaging in one patient, intravenous thrombolysis was administered at 135, 190, 240, and 245 min accordingly. Subacute diffusion-weighted imaging-magnetic resonance imaging confirmed acute ischemic myelopathy in all but one patient. Favorable outcome was achieved in two patients rapidly and in three patients at three-month follow-up. We identified seven other thrombolyzed acute ischemic myelopathy patients in the literature, who showed variable recovery and no hemorrhagic complications.

Conclusions

With appropriate acute imaging, intravenous thrombolysis after acute ischemic myelopathy is feasible and potentially safe within 4.5 h. Given the potential of benefit of thrombolysis in acute ischemic myelopathy, this treatment warrants further efficacy and safety studies.

Imaging of Acute Low Back Pain

Acute low back pain, defined as less than 6 weeks in duration, does not require imaging in the absence of "red flags" that may indicate a cause, such as fracture, infection, or malignancy. When imaging is indicated, it is important to rule out a host of abnormalities that may be responsible for the pain and any associated symptoms. A common mnemonic VINDICATE can help ensure a thorough consideration of the possible causes.

A practical approach to the diagnosis of spinal cord lesions

Every neurologist will be familiar with the patient with atypical spinal cord disease and the challenges of taking the diagnosis forward. This is predominantly because of the limited range of possible clinical and investigation findings making most individual features non-specific. The difficulty in obtaining a tissue diagnosis further contributes and patients are often treated empirically based on local prevalence and potential for reversibility. This article focuses on improving the diagnosis of adult non-traumatic, non-compressive spinal cord disorders. It is structured to start with the clinical presentation in order to be of practical use to the clinician. We aim, by combining the onset phenotype with the subsequent course, along with imaging and laboratory features, to improve the diagnostic process.

Optimizing the Definitions of Stroke, Transient Ischemic Attack, and Infarction for Research and Application in Clinical Practice

BACKGROUND AND PURPOSE

Until now, stroke and transient ischemic attack (TIA) have been clinically based terms which describe the presence and duration of characteristic neurological deficits attributable to intrinsic disorders of particular arteries supplying the brain, retina, or (sometimes) the spinal cord. Further, infarction has been pathologically defined as death of neural tissue due to reduced blood supply. Recently, it has been proposed we shift to definitions of stroke and TIA determined by neuroimaging results alone and that neuroimaging findings be equated with infarction.

METHODS

We examined the scientific validity and clinical implications of these proposals using the existing published literature and our own experience in research and clinical practice.

RESULTS

We found that the proposals to change to imaging-dominant definitions, as published, are ambiguous and inconsistent. Therefore, they cannot provide the standardization required in research or its application in clinical practice. Further, we found that the proposals are scientifically incorrect because neuroimaging findings do not always correlate with the clinical status or the presence of infarction. In addition, we found that attempts to use the proposals are disrupting research, are otherwise clinically unhelpful and do not solve the problems they were proposed to solve.

CONCLUSION

We advise that the proposals must not be accepted. In particular, we explain why the clinical focus of the definitions of stroke and TIA should be retained with continued sub-classification of these syndromes depending neuroimaging results (with or without other information) and that infarction should remain a pathological term. We outline ways the established clinically based definitions of stroke and TIA, and use of them, may be improved to encourage better patient outcomes in the modern era.

Diffusion Tensor Imaging of the Spinal Cord: Clinical Value, Investigational Applications, and Technical Limitations

Although diffusion-weighted imaging (DWI) has become a mainstay in modern brain imaging, it remains less utilized in the evaluation of the spinal cord. Many studies have shown promise in using DWI and diffusion-tensor imaging (DTI) for evaluation of the spinal cord; however, application has been stalled by technical obstacles and artifacts, and questions remain regarding its clinical utility on an individual examination level. This review discusses the background, concepts, and technical aspects of DWI and DTI, specifically for imaging of the spinal cord. The clinical and investigational applications of spinal cord DTI, as well as the practical difficulties and limitations of DWI and DTI for the evaluation of the spinal cord are examined.

Spinal Cord Infarction in the Course of a Septic Shock: About One Case and Review of the Literature

We report the case of a patient admitted to our intensive care unit in the course of a septic shock, secondary to cholangitis. After rapid hemodynamic stabilization, antibiotherapy, and endoscopic extraction of bile ducts stones, she appeared to have developed flaccid paraplegia. The suspected diagnosis of medullar ischemia was confirmed by typical MRI findings. This case stresses the potential pathogenic role of hypotension in medullar ischemia and the place of magnetic resonance imaging (MRI) as a reliable diagnostic tool.

Spinal cord ischemia: aetiology, clinical syndromes and imaging features

INTRODUCTION

The purpose of this study was to analyse MR imaging features and lesion patterns as defined by compromised vascular territories, correlating them to different clinical syndromes and aetiological aspects.

METHODS

In a 19.8-year period, clinical records and magnetic resonance imaging (MRI) features of 55 consecutive patients suffering from spinal cord ischemia were evaluated.

RESULTS

Aetiologies of infarcts were arteriosclerosis of the aorta and vertebral arteries (23.6%), aortic surgery or interventional aneurysm repair (11%) and aortic and vertebral artery dissection (11%), and in 23.6%, aetiology remained unclear. Infarcts occurred in 38.2% at the cervical and thoracic level, respectively, and 49% of patients suffered from centromedullar syndrome caused by anterior spinal artery ischemia. MRI disclosed hyperintense pencil-like lesion pattern on T2WI in 98.2%, cord swelling in 40%, enhancement on post-contrast T1WI in 42.9% and always hyperintense signal on diffusion-weighted imaging (DWI) when acquired.

CONCLUSION

The most common clinical feature in spinal cord ischemia is a centromedullar syndrome, and in contrast to anterior spinal artery ischemia, infarcts in the posterior spinal artery territory are rare. The exclusively cervical location of the spinal sulcal artery syndrome seems to be a likely consequence of anterior spinal artery duplication which is observed preferentially here.

Spinal cord ischemia: practical imaging tips, pearls, and pitfalls

Ischemia of the spinal cord is a rare entity with a poor prognosis. Brain ischemia is no longer a diagnostic challenge; on the contrary, ischemia of the spinal cord remains difficult, particularly in children. In this article, we illustrate the principal causes in children and adults, clinical presentation, different techniques for the diagnosis by MR imaging (diffusion, spinal MR angiography, and 1.5 versus 3T), pathophysiology, and differential diagnosis. We will discuss current knowledge, perspectives, and pitfalls.

Spinal cord infarction and patent foramen ovale: is there a link?

Spinal cord infarction (SCI) is an uncommon but important cause of acute myelopathy. Nevertheless, contrary to cerebral stroke, the discussion about paradoxical embolism as a cause of cryptogenic SCI remains dubious. We describe the case of a 24-year-old woman who developed sudden-onset back pain followed by upper limb paralysis. T2-weighted MRI demonstrated hyperintense signal, extending from C5 to D1 with corresponding restricted diffusion on diffusion-weighted MRI and reduction of the apparent diffusion coefficient. Diagnostic workup, including lumbar puncture, showed no changes. Transcranial Doppler showed a right-to-left shunt with an uncountable number of microembolic signals after Valsalva maneuvers, and a patent foramen ovale (PFO) with an atrial septum aneurysm was identified. We discuss the paucity of evidence of right-to-left shunting in spinal diseases compared to cerebral events and the potential role of paradoxical embolism through PFO as a possible mechanism of SCI.