MRI of spinal cord infarction

Features of non-traumatic spinal cord infarction on MRI: Changes over time

Background and purpose

Spinal cord infarction (SCI) is difficult to diagnosis using MRI findings. We aimed to suggest the optimal timing of MRI studies for diagnosing SCI.

Materials and methods

This retrospective study was approved by our institutional review board. The requirement for informed consent was waived. MRI scans of SCI patients diagnosed between January 2015 and August 2019 were enrolled in the SCI group and subdivided according to the interval between symptom onset and time of MRI scan (A, within 6 h; B, 6–12 hours; C, 12–24 hours; D, 24–72 hours; E, 3–7 days). Three radiologists analyzed the T2WI scans and evaluated the confidence level of diagnosing SCI using a five-point Likert scale: 1, certainly not; 2, probably not; 3, equivocal; 4, probably yes; 5, certainly yes. Scores of 4 and 5 were defined as “T2WI-positive SCI” and scores of 1–3 were defined as “T2WI-negative SCI”.

Results

The SCI group included 58 MRI scans of 34 patients (mean age, 60.6 ± 14.0 years; 18 women). The T2WI positivity rate was 72.4% (42/58). In contrast to the other subgroups, subgroup A included fewer cases of T2WI-positive SCI (1/4, 25%) than T2WI-negative SCI. A confidence score of 5 was the most common in subgroup D (4/27, 14.8%). Among the 12 patients who underwent MRI studies more than twice, confidence scores increased with time.

Conclusion

In patients with suspected SCI showing equivocal initial MRI findings, follow-up MRI studies are helpful, especially when performed between 24 and 72 hours after symptom onset.

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.

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.

Postoperative Paraplegia Coincident with Single Shot Spinal Anaesthesia

Paraplegia is a rare but serious complication of spinal anaesthesia. We report an 83-year-old patient who developed anterior spinal artery syndrome resulting in paraplegia some 24 hours after undergoing spinal anaesthesia for a Moore's hemiarthroplasty. Return of neurologic function was documented prior to the onset of paralysis, with magnetic resonance imaging evidence suggestive of spinal cord infarction.

Cervical disc herniation as a trigger for temporary cervical cord ischemia

BACKGROUND

Disc herniations are only reported in few case reports as a rare cause of acute spinal ischemia. A surgical treatment has not been described so far in these reports with analysis of diffusion weighted magnetic resonance imaging (DWI/MRI) before and after surgery. The aim of our study is to report a case of cervical spinal cord ischemia caused by cervical disc herniation and discuss the literature concerning diagnostic and treatment options.

METHODS

A 72-year-old female patient developed an acute progressive tetraparesis with emphasis on the upper extremities. MRI showed a disc herniation at the cervical segment 5/6 (C5/6) with consecutive spinal canal stenosis and additional signs of spinal cord ischemia in T2-weighted imaging (T2WI) and DWI reaching from C3 to C5 level. With the MRI being highly suggestive for anterior spinal cord ischemia, we hypothesized that this might be caused by compression of the anterior spinal artery through the significant disc herniation. Therefore, we decided to perform an anterior discectomy and fusion at C5/6 level.

RESULTS

Following surgery, the patient's symptoms showed immediate regression with complete recovery after two months in correspondence with the normalization in the control MRI scan of cervical cord.

CONCLUSIONS

Assumedly our patient suffered from a partial anterior spinal artery syndrome, possibly caused by a disc herniation-related compression that was reversible following surgery. This was accompanied by a complete resolution of spinal cord signal abnormalities in T2WI and DWI.

Spinal cord infarction: a rare cause of paraplegia

Spinal cord infarction is rare and represents a diagnostic challenge for many physicians. There are few reported cases worldwide with a prevalence of 1.2% of all strokes. Circulation to the spinal cord is supplied by a rich anastomosis. The anterior spinal artery supplies the anterior two thirds of the spinal cord and infarction to this area is marked by paralysis, spinothalamic sensory deficit and loss of sphincter control depending on where the lesion is. Treatment of spinal cord infarction focuses on rehabilitation with diverse outcomes. This report presents a case of acute spinal cord infarction with acquisition of MRI to aid diagnosis.

Advanced diffusion-weighted magnetic resonance imaging techniques of the human spinal cord

Unlike those of the brain, advances in diffusion-weighted imaging (DWI) of the human spinal cord have been challenged by the more complicated and inhomogeneous anatomy of the spine, the differences in magnetic susceptibility between adjacent air and fluid-filled structures and the surrounding soft tissues, and the inherent limitations of the initially used echo-planar imaging techniques used to image the spine. Interval advances in DWI techniques for imaging the human spinal cord, with the specific aims of improving the diagnostic quality of the images, and the simultaneous reduction in unwanted artifacts have resulted in higher-quality images that are now able to more accurately portray the complicated underlying anatomy and depict pathologic abnormality with improved sensitivity and specificity. Diffusion tensor imaging (DTI) has benefited from the advances in DWI techniques, as DWI images form the foundation for all tractography and DTI. This review provides a synopsis of the many recent advances in DWI of the human spinal cord, as well as some of the more common clinical uses for these techniques, including DTI and tractography.

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

BACKGROUND AND PURPOSE

We report on the use of line scan diffusion magnetic resonance imaging in the evaluation of spinal cord infarctions.

METHODS

Data on 19 patients with clinical findings consistent with spinal cord infarctions and abnormal findings on line scan diffusion imaging were reviewed. The Apparent Diffusion Coefficient (ADC) measurements for the normal spinal cord and for the areas of abnormality were calculated from trace ADC maps.

RESULTS

Restricted diffusion was found in all 19 patients. Absolute ADC values in the ischemic area ranged between 395.4 and 575.8 × 10(-6) mm(2)/s, with ADC ratios ranging between 39.4% and 57.4%.

CONCLUSIONS

Line scan diffusion imaging is technically feasible and appears to be a reliable method to diagnose spinal cord infarction in the acute setting.

Diffusion-weighted imaging in noncompressive myelopathies: a 33-patient prospective study

Diffusion-weighted imaging (DWI) is frequently used to differentiate cerebral lesions. The aim of our study was to evaluate the diagnostic value of DWI and the measurement of the apparent diffusion coefficient (ADC) in noncompressive myelopathy explorations. Thirty-three patients presenting a spinal cord syndrome due to a noncompressive myelopathy underwent spinal cord MRI between September 2005 and November 2008. For each patient, the ADC was calculated in the pathological spinal cord. ADC values were also measured in the healthy spinal cord of ten control subjects. Statistical analysis was based on the Student's t test. Twenty-one patients presented an inflammatory myelopathy: Nine patients presented multiple sclerosis, three patients presented a parainfectious myelopathy, two patients acute disseminated encephalomyelitis, one patient neuromyelitis optica, one patient systemic lupus erythematosus, and five patients a myelopathy of unknown aetiology. Six patients presented a spinal cord infarction. ADC values were significantly lower in spinal cord infarct (mean ADC = 0.81 +/- 0.08 x 10(-3) mm(2)/s) than in inflammatory spinal cord lesions (mean ADC = 1.37 +/- 0.23 x 10(-3) mm(2)/s) and in healthy control spinal cord (mean ADC = 0.93 +/- 0.07 x 10(-3) mm(2)/s). These results are important to differentiate ischaemic from inflammatory myelopathies, especially at the acute phase when clinical presentation and extensive work-up are not able to show an aetiologic diagnosis. Although these results are similar to those described in cerebral explorations, ADC measurements remain technically limited for the moment.

Diffusion-weighted imaging, diffusion-tensor imaging, and fiber tractography of the spinal cord

In the brain, diffusion-weighted imaging (DWI) is an established and reliable method for the characterization of neurologic lesions. Although the diagnostic value of DWI in the early detection of ischemia has not diminished with time, many new clinical applications of DWI have also emerged. Diffusion-tensor imaging and fiber tractography have more recently been developed and optimized, allowing quantification of the magnitude and direction of diffusion along three principal eigenvectors. Diffusion-tensor imaging and fiber tractography are proving to be useful in clinical neuroradiology practice, with application to several categories of disease, and to be a powerful research tool. This article describes some of the applications of DWI and diffusion-tensor imaging in the evaluation of the diseases of the spinal cord.

Imaging in spinal vascular disease

Spinal vascular diseases are rare and constitute only 1% to 2% of all vascular neurologic pathologies. In this article, the following vascular pathologies of the spine are described: spinal arterial infarcts, spinal cavernomas, and arteriovenous malformations (including perimedullary fistulae and glomerular arterivenous malformations), and spinal dural arteriovenous fistulae. This article gives an overview about their imaging features on MRI, MR angiography, and digital subtraction angiography. Clinical differential diagnoses, the neurologic symptomatology, and the potential therapeutic approaches of these diseases, which might vary depending on the underlying pathologic condition, are given.

Diffusion-weighted MR imaging (DWI) in spinal cord ischemia

INTRODUCTION

Spinal cord infarction is a rare clinical diagnosis characterized by a sudden onset of paralysis, bowel and bladder dysfunction, and loss of pain and temperature perception, with preservation of proprioception and vibration sense. Magnetic resonance imaging (MRI) usually demonstrates intramedullary hyperintensity on T2-weighted MR images with cord enlargement. However, in approximately 45% of patients, MR shows no abnormality. Diffusion-weighted MR imaging (DWI) has been widely used for the evaluation of a variety of brain disorders, especially for acute stroke. Preliminary data suggest that DWI has the potential to be useful in the early detection of spinal infarction.

METHODS

We performed DWI, using navigated, interleaved, multishot echo planar imaging (IEPI), in a series of six patients with a clinical suspicion of acute spinal cord ischemia.

RESULTS

In all patients, high signal was observed on isotropic DWI images with low ADC values (0.23 and 0.86x10(-3) cm(2)/s), indicative of restricted diffusion.

CONCLUSION

We analyzed the imaging findings from conventional MR sequences and diffusion-weighted MR sequences in six patients with spinal cord infarction, compared the findings with those in published series, and discuss the value of DWI in spinal cord ischemia based on current experience. Although the number of patients with described DWI findings totals only 23, the results of previously published studies and those of our study suggest that DWI has the potential to be a useful and feasible technique for the detection of spinal infarction.

Diffusion imaging of the human spinal cord and the vertebral column

During the last decade, diffusion-weighted imaging (DWI) has matured from an experimental tool to a clinically useful modality that has not only significantly impacted the diagnosis of (acute) cerebral stroke but has also shown utility in other abnormalities of the brain. Although DWI should be equally sensitive to changes in the spine, it has been used far less frequently in this region of the body. This is mainly because of the inhomogeneous magnetic environment, the small size of the spinal cord, and increased motion in and around the spine. However, once these limitations are overcome, a whole range of applications can be envisioned. Already now, DWI promises to be able to differentiate between benign and malignant vertebral compression fractures. As in the brain, the immediate reduction of diffusivity following ischemic damage in the spinal cord may provide an early identification of patients with infarction. The study of diffusion anisotropy may open new avenues for the detection and better understanding of damage to the long fiber tracts with important clinical implications for disorders like multiple sclerosis and amyotrophic lateral sclerosis. It may also be possible to address, in a more refined manner, mechanisms of damage such as occur with spondylotic myelopathy. To lay the basis for future research in these areas, we will discuss the most appropriate DWI methods for the spine. Following an overview of the basic principles of DWI and associated pitfalls, the most commonly used imaging methods are addressed. Finally, experimental and clinical applications in the spinal cord and the vertebral column and their clinical relevance thus far are reviewed.

Diffusion tensor imaging in spinal cord: methods and applications - a review

The spinal cord is a clinically eloquent site within the central nervous system, containing important sensorimotor tracts confined within a small cross-sectional area. Damage to the spinal cord may be caused by a wide range of pathologies, and can result in profound functional disability. Characterization of the structural integrity of the spinal cord can be assessed using diffusion tensor imaging methods. Development and application of this technique may improve our understanding of the nature and evolution of structural damage in spinal cord disease. Possible developments include improved detection of ischaemic lesions, clarification of the relationship between clinical disability and structural damage to the cord and monitoring of anti-inflammatory or neuroprotective therapies. In this review current technical aspects, clinical applications and the suggested future development of spinal cord diffusion imaging are discussed.

Feasibility study of non Carr Purcell Meiboom Gill single shot fast spin echo in spinal cord diffusion imaging

The fast spin echo (FPE) sequence is sensitive to the phase of the magnetization, hindering its use in procedures such as diffusion imaging. The current solutions to this problem reduce the available signal by one half. We present the first volunteer study of a sequence which does not suffer from this loss of signal while measuring diffusion coefficients.