The yield of initial conventional MRI in 115 cases of angiographically confirmed spinal vascular malformations

Delayed Diagnosis of Spinal Dural Arteriovenous Fistula: A Case Report and Scoping Review

Spinal dural arteriovenous fistula (SDAVF) is among the most common arterial shunt diseases typically found in middle aged or older men. Herein, we aimed to clarify the reasons for misdiagnoses and delayed diagnoses of SDAVF, determine how these affect prognoses, and establish how they can be prevented. We conducted a PubMed/MEDLINE literature search using "spinal dural arteriovenous fistula", "delayed diagnosis", "late diagnosis", and "misdiagnosis" terms. We identified 18 articles, including 965 SDAVF cases. Patients were predominantly males (71.8-100.0%) (mean age: 53.5-71.0 years). Misdiagnoses rates varied (17.5-100.0%) and encompassed many conditions. The mean time between early manifestations and confirmed diagnosis was approximately 10-15 months and from the first radiologic image revealing dural arteriovenous fistula (DAVF) features to diagnosis was 9.2-20.7 months. Posttreatment outcomes showed a significant improvement in motor functions, gait, and micturition, particularly in patients exhibiting preoperative symptoms over a short period. SDAVF is frequently misdiagnosed or subject to delayed diagnosis, causing poor clinical outcomes. SDAVF symptoms including progressive lower-limb weakness, paresthesia, and vesicorectal dysfunction are indications for spinal magnetic resonance imaging with subsequent spinal angiography, wherein DAVF is evidenced by extensive T2 hyperintensity and flow-void abnormalities. We reported a representative case with delayed diagnosis.

Early diagnosis of thoracic spinal dural arteriovenous fistula using lumbar magnetic resonance imaging: A case report

In middle-aged and older men, clinicians often suspect lumbar spine disease when gait is impaired with intermittent claudication, but spinal dural arteriovenous fistula (SDAVF) may be the etiology. An understanding of the key magnetic resonance imaging findings of SDAVF is necessary for early diagnosis, appropriate treatment, and minimization of complications.

Spinal cord motor disorders

Spinal cord diseases are frequently devastating due to the precipitous and often permanently debilitating nature of the deficits. Spastic or flaccid paraparesis accompanied by dermatomal and myotomal signatures complementary to the incurred deficits facilitates localization of the insult within the cord. However, laboratory studies often employing disease-specific serology, neuroradiology, neurophysiology, and cerebrospinal fluid analysis aid in the etiologic diagnosis. While many spinal cord diseases are reversible and treatable, especially when recognized early, more than ever, neuroscientists are being called to investigate endogenous mechanisms of neural plasticity. This chapter is a review of the embryology, neuroanatomy, clinical localization, evaluation, and management of adult and childhood spinal cord motor disorders.

Identification of specific causes of myelopathy in a large cohort of patients initially diagnosed with transverse myelitis

BACKGROUND AND OBJECTIVES

Identifying the etiologic diagnosis in patients presenting with myelopathy is essential in order to guide appropriate treatment and follow-up. We set out to examine the etiologic diagnosis after comprehensive clinical evaluation and diagnostic work-up in a large cohort of patients referred to our specialized myelopathy clinic, and to explore the demographic profiles and symptomatic evolution of specific etiologic diagnoses.

METHODS

In this retrospective study of patients referred to the Johns Hopkins Myelitis and Myelopathy Center between 2006 and 2021 for evaluation of "transverse myelitis", the final etiologic diagnosis determined after comprehensive evaluation in each patient was reviewed and validated. Demographic characteristics and temporal profile of symptom evolution were recorded.

RESULTS

Of 1193 included patients, 772 (65%) were determined to have an inflammatory myelopathy and 421 (35%) were determined to have a non-inflammatory myelopathy. Multiple sclerosis/clinically isolated syndrome (n = 221, 29%) and idiopathic myelitis (n = 149, 19%) were the most frequent inflammatory diagnoses, while spinal cord infarction (n = 197, 47%) and structural causes of myelopathy (n = 108, 26%) were the most frequent non-inflammatory diagnoses. Compared to patients with inflammatory myelopathies, patients with non-inflammatory myelopathies were more likely to be older, male and experience chronic symptom evolution (p < 0.001 for all). Hyperacute symptom evolution was most frequent in patients with spinal cord infarction (74%), while chronic symptom evolution was most frequent in patients with structural causes of myelopathy (81%), arteriovenous fistula or arteriovenous malformation (81%), myelopathy associated with rheumatologic disorder (71%), and sarcoidosis-associated myelopathy (61%).

CONCLUSIONS

Patients initially diagnosed with "transverse myelitis" are eventually found to have a more specific inflammatory or even non-inflammatory cause, potentially resulting in inappropriate treatment and follow-up. Demographic characteristics and temporal profile of symptom evolution may help inform a differential diagnosis in these patients. Etiological diagnosis of myelopathies would provide better therapeutic decisions.

Clinical heterogeneity of low flow spinal arteriovenous fistulas; a case series

Background

Spinal AVF (SAVF), a potentially treatable cause of myelopathy, remains a challenging diagnosis. Its rarity and non-specific imaging findings often result in misdiagnosis despite a high index of clinical suspicion. The classically described high T2 signal in the spinal cord or prominent vascular flow voids in the intradural space were not infrequently missed on initial imaging, only to be picked up at follow-up imaging after progression of symptoms. Additionally, small sized fistulas(< 1 mm) and SAVF involving less frequent locations like the craniocervical junction in a patient presenting with paraplegia further complicates the diagnosis. On rare occasions, acute atypical presentation following a surgery adds to the conundrum. Definite diagnosis with spinal angiography, the gold-standard modality requires the expertise of highly skilled interventionists which may otherwise lead to false negative findings. We describe four SAVF patients with unconventional presentations, highlighting less described clinical findings.

Case presentation

First was a 50-year-old man presented with spastic paraparesis and was found to have an AVF at the cervical region arising from the vertebral artery. Second, a 45-year-old man with acute paraplegia post-operatively, initially treated for a transverse myelitis before lumbar region AVF was detected. Thirdly, a 27-year-old man presented with subacute lower thoracic myelopathy and deteriorated after corticosteroid treatment. The last patient, who initially appeared to have conus medullaris/cauda equina syndrome had a SAVF at the mid thoracic level. Presentation varied with some exhibiting acute deterioration mimicking other spinal cord pathology such as inflammatory disorders. All patients eventually underwent endovascular treatment with successful embolization of SDAVF. None of them exhibited further neurological deterioration after embolization.

Conclusion

Successful treatment of SAVF is possible provided the diagnosis is made early, allowing timely intervention. Certain clues may aid the diagnosis. Firstly, arteriovenous fistula can be located distant to the clinical localization of myelopathy resulting in the unexpected longitudinally extensive spinal cord signal change. This clinical-radiological discrepancy can be a useful clue in diagnosing SAVF. Secondly, an acute myelopathic presentation immediately post-surgery may be related to SAVF. Other SAVF feature of note includes progressive myelopathy mimicking immune-mediated myelitis among young adults below 30 years of age refractory to immune therapy.

A case series of intracranial dural arteriovenous fistulae mimicking cervical myelitis: a diagnosis not to be missed

Objective

To describe the diagnostic features of intracranial dural arteriovenous fistulae (DAVF) presenting with cervical cord or brainstem swelling.

Methods

Retrospective case note and neuroimaging review of patients with angiographically confirmed DAVF diagnosed during January 2015–June 2020 at a tertiary neuroscience centre (Walton Centre NHS Foundation Trust, Liverpool, UK).

Results

Six intracranial DAVF causing cervical cord or brainstem oedema (all males aged 60–69 years) and 27 spinal DAVF (88% thoracolumbar) were detected over a 5.5-year period. Significantly more patients with intracranial DAVF received steroids for presumed inflammatory myelitis than those with spinal DAVF (5/6 vs 1/27, p = 0.0001, Fisher’s exact test). Several factors misled the treating clinicians: atypical rostral location of cord oedema (6/6); acute clinical deterioration (4/6); absence (3/6) or failure to recognise (3/6) subtle dilated perimedullary veins on MRI; intramedullary gadolinium enhancement (2/6); and elevated CSF protein (4/5). Acute deterioration followed steroid treatment in 4/5 patients. The following features may suggest DAVF rather than myelitis: older male patients (6/6), symptomatic progression over 4 or more weeks (6/6) and acellular CSF (5/5).

Conclusion

Intracranial DAVF are uncommon but often misdiagnosed and treated as myelitis, which can cause life-threatening deterioration. Neurologists must recognise suggestive features and consider angiography, especially in older male patients. Dilated perimedullary veins are an important clue to underlying DAVF, but may be invisible or easily missed on routine MRI sequences.

Spinal vascular malformations: Angiographic evaluation and endovascular management

Spinal vascular malformations (SVM) are classified based on their location (intramedullary, perimedullary, radicular, extradural) and flow pattern (high-flow, low-flow, no arteriovenous shunt). High-flow SVMs are generally congenital lesions diagnosed in children and young patients without gender predominance. They present with hemodynamic disturbances, mass effect, or hemorrhages, but may also be discovered incidentally. Low-flow SVMs tend to be acquired lesions presenting in older men with progressive myelopathy caused by spinal venous hypertension. They are rarely associated with vascular syndromes but may accompany prothrombotic conditions. The sensitivity and specificity of conventional MRI are excellent for high-flow SVMs but poor for low-flow lesions, which are frequently diagnosed with extensive delays reducing the potential for favorable outcomes. The sensitivity of advanced MRI techniques remains unclear, notably for the detection of low-flow shunts without flow voids on conventional MRI. Catheter angiography remains the gold standard modality for the evaluation of the spinal vasculature and its disorders. SVMs can be treated by surgical or endovascular means. Initially plagued by high recurrence rates due to inadequate embolization material, endovascular techniques represent nowadays a valid alternative to surgery, thanks notably to the introduction of liquid embolic agents.

Spinal fistulas documented by contrast enhanced computed tomography during myelopathy workup: a lost opportunity

PURPOSE

Low-flow spinal arteriovenous fistulas (SAVFs) with intradural venous drainage typically manifest with a progressive venous hypertensive myelopathy (VHM) in older patients. VHM is difficult to identify. MRI is often nonspecific, and many cases are initially misdiagnosed, most often as transverse myelitis. The workup of myelopathic patients frequently includes thoracic and/or abdominal contrast-enhanced CT (CECT) that are generally not reviewed by neuroradiologists. The purpose of this work was to investigate how often abnormal enhancing intracanalar structures corresponding to the draining veins of a low-flow SAVF were documented by CECT.

MATERIALS AND METHODS

We evaluated 92 consecutive patients with low-flow SAVFs and VHM treated at our institution between 2009 and 2018. The study group included 22 of these patients with at least one thoracoabdominal CECT available for review. The control group consisted of 20 consecutive myelopathy patients with negative angiography and at least one thoracoabdominal CECT. Intracanalar enhancing structures were classified either as (i) conspicuous or (ii) equivocal or absent.

RESULTS

One CECT in the study group was technically inadequate. Conspicuous intracanalar enhancing structures were observed in 20 of the remaining 21 patients with SAVFs (95.2%) and in 2 of 20 control patients (10%). None of the enhancing intracanalar structures was mentioned in official study reports.

CONCLUSIONS

The presence of enhancing vascular structures within the spinal canal on thoracoabdominal CECT obtained during the workup of myelopathies appears to represent a powerful but currently underappreciated tool for the detection of low-flow SAVFs.

Clinical characteristics, misdiagnosis and outcomes of patients with low-flow spinal arteriovenous fistulas

OBJECTIVE

To describe the clinical characteristics, delay to diagnosis and post-intervention outcomes of patients with low-flow spinal arteriovenous fistulas (SAVFs).

METHODS

In this retrospective observational study, we reviewed all patients with low-flow SAVFs angiographically diagnosed at our institution between 2008 and 2018. Pre- and post-intervention disability levels were recorded using the modified Aminoff and Logue scale (mALS).

RESULTS

One-hundred and five patients were included. Median age was 62 years and 79% were male. Most patients (56%) presented to neurologists and 41% were misdiagnosed with myelitis. Patients underwent unnecessary treatment with corticosteroids (44%), other immunosuppressive therapies (8%) and spinal surgery (10%). Inappropriate corticosteroid treatment led to a precipitous clinical decline in 30% of patients exposed. Only 21% percent of patients were correctly diagnosed after initial evaluation; the median delay to diagnosis in the rest of the cohort was of 12 months (IQR 7 to 24 months). Longer delays to diagnosis were associated with higher levels of disability (p = .002). Treatment of SAVF was endovascular in 64% and surgical in 26%; 13% of patients required further intervention due to incomplete initial treatment or fistula recurrence. Greater than 6 months after intervention, disability scores were improved in 52% and stable in 43% of patients. In individual patients, pre- and post-intervention disability scores were strongly correlated (p < .001).

CONCLUSIONS

Low-flow SAVFs are associated with substantial disability and are frequently misdiagnosed. Timely diagnosis of SAVF needs to improve, as endovascular or surgical treatment results in stabilization or improvement of disability in the vast majority of patients.

The role of spinal angiography in the evaluation and treatment of pediatric spinal vascular pathology: a case series and systematic review

OBJECT

While it has been extensively studied in adults, the role of spinal angiography in children with suspected spinal vascular malformations is not fully characterized. With special implications regarding technique, radiation dose, and pathology, we sought to review our single-center experience with pediatric spinal vascular pathology and use a systematic review of the literature to further identify its role in pediatrics.

METHODS

A retrospective chart review was conducted under IRB approval for all patients age 0-18 years old who underwent spinal angiography at our institution between 2007 and 2018 for concern for spinal vascular pathology. A simultaneous systematic review was conducted via dedicated search terms in two distinct databases and reviewed to identify all studies referring to spinal angiography or angiograms in pediatric patients.

RESULTS

Six patients were included. Three patients (50%) had vascular malformations confirmed on diagnostic angiography and underwent subsequent endovascular treatment. Two patients (33.3%), one with hematomyelia and one with spinal cord infarction, had negative diagnostic angiograms. One patient (16.7%) had a spinal tumor and underwent angiography for further evaluation preoperatively. Spinal angiography was used to aid in diagnosis, preoperative planning, and treatment in these cases. It was demonstrated to be safe in this patient population, with no untoward events, minimal radiation dose, and possible therapeutic applications in select cases. The systematic review identified 11 studies regarding pediatric spinal angiography. These ranged from single case reports to case series of up to 38 patients and highlighted the role of spinal angiography in diagnosis, endovascular treatment, preoperative planning, and postoperative follow-up.

CONCLUSIONS

Spinal angiography may be used in a variety of scenarios to better understand the architecture of vascular spinal lesions and facilitate endovascular intervention. While its application in both adult and pediatric pathology is limited to select cases, spinal angiography remains a key diagnostic procedure when approaching vascular lesions or tumors of the spine, assessing for etiology of spinal cord infarcts, and in the evaluation of unexplained hemorrhage in the spinal canal.

Comparative Analysis of Volumetric High-Resolution Heavily T2-Weighted MRI and Time-Resolved Contrast-Enhanced MRA in the Evaluation of Spinal Vascular Malformations

BACKGROUND AND PURPOSE

Volumetric high-resolution heavily T2-weighted imaging or time-resolved contrast-enhanced MRA is used in the detection and characterization of spinal vascular malformations, though inherent trade-offs can affect their overall sensitivity and accuracy. We compared the efficacy of volumetric high-resolution heavily T2-weighted and time-resolved contrast-enhanced images in spinal vascular malformation diagnosis and feeder characterization and assessed whether a combined evaluation improved the overall accuracy of diagnosis.

MATERIALS AND METHODS

Twenty-eight patients with spinal vascular malformations (spinal dural arteriovenous fistula, spinal cord arteriovenous malformation, and perimedullary arteriovenous fistula) were prospectively enrolled. MR images were separately analyzed by 2 neuroradiologists blinded to the final diagnosis.

RESULTS

Both sequences demonstrated 100% sensitivity and 93.5% accuracy for the detection of spinal vascular malformations. Volumetric high-resolution heavily T2-weighted imaging was superior to time-resolved contrast-enhanced MR imaging for identification of spinal cord arteriovenous malformations (100% versus 90% sensitivity and 96.7% versus 93.5% accuracy), however, for the diagnosis of perimedullary arteriovenous fistula, time resolved contrast enhanced MRI was found to perform better than the volumetric T2 sequence (80% versus 60% sensitivity and 96.7% versus 93.5% accuracy). Both sequences showed equal sensitivity (100%) and accuracy (87%) for spinal dural arteriovenous fistulas. Combined evaluation improved the overall accuracy across all types of spinal vascular malformation. Volumetric high-resolution heavily T2-weighted imaging was superior or equal to time-resolved contrast-enhanced MR imaging for feeder identification of spinal dural arteriovenous fistulas for both observers (90.9% and 72.7% versus 72.7%), which improved to 90.9% when the sequences were combined. Time-resolved contrast-enhanced MR imaging performed better for major and total feeder identification of spinal cord arteriovenous malformation (80% versus 60%) and perimedullary arteriovenous fistula (80% versus 60%-80%).

CONCLUSIONS

Combined volumetric high-resolution heavily T2-weighted imaging and time-resolved contrast-enhanced MR imaging can improve the sensitivity and accuracy of spinal vascular malformation diagnosis, classification, and feeder characterization.

Volumetric T2-weighted MRI improves the diagnostic accuracy of spinal vascular malformations: comparative analysis with a conventional MR study

Background

To date, very little study of the importance of a volumetric T2-weighted MR sequence in the evaluation of spinal vascular malformations (SVMs) has been carried out.

Objective

To determine the utility and accuracy of a volumetric T2 MR sequence compared with conventional T2 in the diagnosis of SVMs.

Methods

Retrospective analysis of all patients who underwent spinal DSA for suspected SVMs was conducted. Conventional T2 and volumetric T2 MR images were analysed for the presence of flow voids and parenchymal changes, and SVMs were characterized. The sensitivity, specificity, and overall diagnostic accuracy of these MRI diagnoses were calculated.

Results

Of 89 subjects included in the final analysis, 70 patients had angiographically proved SVMs (38 patients with spinal cord arteriovenous malformations [SCAVM—intramedullary or perimedullary] and 32 cases of spinal dural arteriovenous fistula (SDAVF)) and the remaining 19 subjects were normal. The sensitivity and specificity for identification of SVMs were 98.1% and 90% for volumetric T2 sequences, compared with 82.8% and 89.4% for conventional T2 MRI, respectively. For characterization of spinal vascular lesions, volumetric MRI showed high sensitivity, specificity, and accuracy for SDAVF (100%, 90%, 97%, respectively) compared with conventional T2 MRI (71.8%, 89%, 79%, respectively). The positive likelihood ratio was high and negative likelihood ratio was zero for volumetric MRI evaluation of SDAVF, while these ratios were comparable between the two sequences for SCAVM.

Conclusion

Volumetric T2 MRI is highly sensitive for the detection of SVMs, especially for SDAVF. Volumetric T2 MRI could be introduced into routine clinical practice in the screening of suspected SVMs.

Intracranial dural arteriovenous fistula mistaken as cervical transverse myelitis

We describe a man with an intracranial dural arteriovenous fistula that presented as a subacute longitudinally extensive cervical myelopathy. The uncommon location of the fistula and the absence of specific radiological signs resulted in initial misdiagnosis as longitudinally extensive transverse myelitis. Neurologists should have a high index of suspicion for dural arteriovenous fistula in older men, especially those with subacute or chronic symptoms, acellular cerebrospinal fluid and, particularly, if there is neurological deterioration soon after corticosteroid treatment. Patients need early angiography to identify this treatable cause of myelopathy.