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Background and Purpose: Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks. This study assessed whether the certainty and/or multifocality of CSF leaks is associated with the severity of intracranial sequelae of SIH., Materials and Methods: A retrospective review was completed of patients with suspected SIH that underwent digital subtraction myelogram (DSM) preceded by brain MRI. DSMs were evaluated for the presence or absence of a CSF leak, categorized both as positive/negative/indeterminate and single versus multifocal. Brain MRIs were assessed for intracranial sequelae of SIH based on two probabilistic scoring systems (Dobrocky and Mayo methods). For each system, both an absolute "numerical" score (based on tabulation of findings) and "categorized" score (classification of probability) were tabulated., Results: 174 patients were included; 113 (64.9%) were female, average age 52.0 ± 14.3 years. One or more definite leaks were noted in 76 (43.7%) patients; an indeterminate leak was noted in 22 (12.6%) patients. 16 (16.3%) had multiple leaks. There was no significant difference in the severity of intracranial findings between patients with a single versus multiple leaks ( p values ranged from .36 to .70 using categorized scores and 0.22-0.99 for numerical scores). Definite leaks were more likely to have both higher categorized intracranial scores (Mayo p = .0008, Dobrocky p = .006) and numerical scores ( p = .0002 for Mayo and p = .006 for Dobrocky)., Conclusions: Certainty of a CSF leak on diagnostic imaging is associated with severity of intracranial sequelae of SIH, with definite leaks having significantly more intracranial findings than indeterminate leaks. Multifocal leaks do not cause greater intracranial abnormalities., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Spontaneous intracranial hypotension (SIH) caused by a spinal cerebrospinal fluid (CSF) leak classically presents with orthostatic headache. Digital subtraction myelography (DSM) has a well-established diagnostic yield in the absence of extradural spinal collection. At our institution, DSM is followed by lateral decubitus CT myelogram (LDCTM) in the same decubitus position to increase diagnostic yield of the combined study. We evaluated the incremental diagnostic yield of LDCTM following negative DSM and reviewed patient outcomes., Methods: Retrospective review of consecutive DSMs with subsequent LDCTM from April 2019 to March 2021 was performed. Combined reports were reviewed, and studies with positive DSMs were excluded. Of the exams with negative DSM, only studies with LDCTM reports identifying potential leak site were included. Interventions and follow-up clinical notes were reviewed to assess symptoms improvement following treatment., Results: Of the 83 patients with negative DSMs, 11 (13.2%) had positive leak findings on LDCTMs, and 21 (25.3%) were equivocal. Of 11 positive LDCTMs, 6 leaks were nerve sheath tears (NSTs) and 5 were CSF-venous fistulas (CVFs). 10/11 (90.9%) had intervention and follow-up, with 9/10 (90%) having positive clinical outcome. Of the 21 equivocal LDCTM patients (19 CVFs and 2 NSTs), 15 (71.4%) had interventions and follow-up, with 3/15 (20.0%) with positive clinical outcomes., Conclusion: LDCTM following negative DSM has an incremental diagnostic yield up to 38.6%, with up to 14.5% of positive patient outcomes following treatment. LDCTM should be considered after DSM to maximize diagnostic yield of the combined exam., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

CSF-venous fistulas (CVFs), first described in 2014, are an important cause of spontaneous intracranial hypotension. CVFs can be challenging to detect on conventional anatomic imaging because, unlike other types of spinal CSF leak, they do not typically result in pooling of fluid in the epidural space, and imaging signs of CVF may be subtle. Specialized myelographic techniques have been developed to help with CVF identification, but these techniques are not yet widely disseminated. This article reviews the current understanding of CVFs, emphasizing correlations between venous anatomy and imaging findings as well as potential mechanisms for pathogenesis, and describes current imaging techniques used for CVF diagnosis and localization. These techniques are broadly classified into fluoroscopy-based methods, including digital subtraction myelography and dynamic myelography, and cross-sectional methods, including decubitus CT myelography and MR myelography with intrathecal injection of gadolinium. Knowledge of these various options, including their relative advantages and disadvantages, is critical in the care of patients with spontaneous intracranial hypotension. Investigation is ongoing, and continued advances in knowledge about CVFs as well as in optimal imaging detection are anticipated.

Background: Spontaneous cerebrospinal fluid (CSF) leaks can be an intractable cause of orthostatic headaches but have several treatable causes. CSF-venous fistulas are an increasingly recognized cause of rapid CSF leaks. Although CSF-venous fistulas have been previously reported in the literature, their imaging appearance, associated anomalies, and treatment are incompletely understood. We present a case of a CSF-venous fistula draining to adjacent venous malformations with symptoms responding to surgical treatment. This is the first such case to our knowledge showing enhancement of venous malformations on computed tomography myelography., Case Description: A 61-year-old woman with known soft tissue venous malformations presented with progressive hearing loss, headaches, and nausea. Brain magnetic resonance imaging performed at an outside institution showed findings of CSF hypotension. Her symptoms were refractory to a single-level blood patch. Digital subtraction and computed tomography myelography performed at our institution showed CSF-venous fistulas arising from thoracic nerve root sleeve diverticula and draining to paraspinal venous malformations. She was treated with surgical ligation of the fistula and associated nerve roots. At 3-month follow-up, she reported improvement in her headaches, and magnetic resonance imaging showed resolution of all brain abnormalities., Conclusions: CSF-venous fistulas are a relatively uncommon cause of spontaneous CSF leaks. Though difficult to diagnose, they can respond to surgical treatment as seen in this case. In our experience, decubitus digital subtraction myelography combined with computed tomography myelography is instrumental in making the diagnosis and fully characterizing any abnormalities associated with the fistula. This case also supports the suggested association between CSF-venous fistulas and venous malformations, which is worthy of continued study., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Dynamic CT myelography is used to precisely localize fast spinal CSF leaks. The procedure is most commonly performed in the prone position, which successfully localizes most fast ventral leaks. We have recently encountered a small subset of patients in whom prone dynamic CT myelography is unsuccessful in localizing leaks. We sought to determine the added value of lateral decubitus dynamic CT myelography, which is occasionally attempted in our practice, in localizing the leak after failed prone dynamic CT myelography. We retrospectively identified 6 patients who underwent lateral decubitus dynamic CT myelography, which was performed in each case because their prone dynamic CT myelogram was unrevealing. Two neuroradiologists independently reviewed preprocedural spine MRI and all dynamic CT myelograms for each patient. Lateral decubitus positioning allowed for precise leak localization in all 6 patients. Five of six patients were noted to have dorsal and/or lateral epidural fluid collections on spine MRI. One patient had a single prominent diverticulum on spine MRI (larger than 6 mm), whereas the others had no prominent diverticula. Our study suggests that institutions performing dynamic CT myelography to localize fast leaks should consider a lateral decubitus study if performing the study in the prone position is unrevealing. Furthermore, the presence of dorsal and/or lateral epidural fluid collections on spine MRI may suggest that a lateral decubitus study is of higher yield and could be considered initially. [ABSTRACT FROM AUTHOR]

Keywords: anterior skull base; cerebrospinal fluid leak; radioanatomic study; bone mineral density EN anterior skull base cerebrospinal fluid leak radioanatomic study bone mineral density 804 806 3 03/25/21 20210401 NES 210401 Spontaneous cerebrospinal fluid rhinorrhea (SCSFR) is a distinct clinical entity in which the integrity of skull base has been breached, resulting in leakage of CSF into the nasal cavity.1,2 Although a number of potential contributing etiologies to SCSFR have been addressed,3 elevated intracranial pressure (ICP) is widely considered to be the strongest contributing factor.3-5 It has been hypothesized that chronic elevation of ICP transmits hydrostatic pressure against the cranial base, leading to defects in areas of thinner bone.6 To date, there has been minimal investigation into other factors that may predispose patients with elevated BMI and ICP to develop SCSFR. Anterior skull base thickness, dehiscence, and association with CSF leak The bone of the skull base was thinner in the CSF leak group compared with the matched control groups at each of the points of interest. Right: Sagittal image showing the measurement around the posterior table and planum sphenoidale. gl Results Patients' characteristics Eighty-one patients, including 30 CSF leak patients and 25 nonobese control patients and 26 obese control patients, participated in the study. [Extracted from the article]

To describe clinical and radiographic outcomes of surgical repair of cerebrospinal fluid–venous fistula (CVF), an increasingly recognized cause of spontaneous intracranial hypotension that is poorly responsive to epidural blood patch (EBP). Retrospective review identified adult patients who had lateral decubitus digital subtraction myelography indicative of cerebrospinal fluid leak at Mayo Clinic between November 2018 and February 2020, with clearly localized CVF, followed by surgical treatment. Patients without available imaging before or after surgery were excluded. History of EBP and clinical response to EBP were evaluated along with surgical outcomes. Of 25 patients with CVF who met protocol criteria and were included in the data analysis, 22 (88%) received EBP, but clinical benefit lasting ≥4 weeks occurred in only 2 of 22 (9%). Headache was the most prominent preoperative feature among patients (24/25; 96%). Following surgery, 18 of 24 (75%) patients had complete headache improvement, 4 (17%) had partial improvement, and 2 (8%) had no improvement. Ten of 25 (40%) patients reported cognitive disturbance at baseline; at follow-up, 5 of 10 (50%) had complete improvement, 3 (30%) had partial improvement, and 2 (20%) had no improvement. On postoperative brain magnetic resonance imaging, 6 of 25 (24%) patients had complete resolution of findings by Bern score criteria, 18 (72%) showed partial improvement, and 1 (4%) patient showed no improvement. Adverse events were minor and included surgical site pain and paresthesias. Surgical repair of CVF resulted in improvements in headache and other symptoms, with few side effects. [ABSTRACT FROM AUTHOR]