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Cerebrospinal fluid leaks are important to recognize because they can cause debilitating symptoms for patients and have life-threatening complications. Leakage of cerebrospinal fluid (CSF) from the subarachnoid space can occur at the cranial or spinal level, with distinct clinical presentations, diagnostic evaluations, and treatment modalities depending on the type and location of the leak. Spontaneous, traumatic, and iatrogenic spinal CSF leaks cause reduced intracranial CSF volume and the clinicoradiologic syndrome commonly called “intracranial hypotension”. This review discusses the clinical presentations, etiologies, and risk factors of spinal and cranial CSF leaks.

Spinal cerebrospinal fluid (CSF) leaks require advanced myelographic techniques for precise localization, which is in turn necessary for optimal treatment. Here, we will discuss the various myelographic techniques that have become available in recent years for CSF leak localization. Each of these can be used to detect many different types of spinal CSF leaks, although each modality has unique advantages and disadvantages, which will be outlined here.

CT myelography has been traditionally used to evaluate post-operative paraspinal fluid collections to discern CSF leaking into a pseudomeningocele versus a contained seroma. Rather than performing a lumbar puncture and injecting intrathecal contrast for myelography, we present the first report of direct contrast injection into a post-operative paraspinal pseudomeningocele for CSF leak confirmation and localization. This is a simple procedure that has several advantages over a conventional CT myelogram for the evaluation of post-operative paraspinal fluid collections.

Cerebrospinal fluid-venous fistula (CVF) is an important cause of spontaneous intracranial hypotension (SIH), a condition characterized by low cerebrospinal fluid (CSF) volume and orthostatic headaches. The pathogenesis of CVF is thought to be direct connection of the spinal dura to one or more veins in the epidural space, allowing unregulated flow of CSF into the venous system. Herein, we provide a comprehensive review of the endovascular management of CVF in patients with SIH. We also focus on the various techniques and devices used in endovascular treatment, as well as the pathogenesis, diagnosis, and alternative treatment options of CVF.

Cauda Equina Neuroendocrine Tumors (CE-NET), previously referred to as paragangliomas are a rare subset of spinal tumors, with limited data on imaging. Herein, we present a retrospective review of clinical and imaging findings of CE-NETs in ten patients who were evaluated at our institution over the past two decades. All patients had well-defined intradural lesions in the lumbar spine which demonstrated slow growth. A review of imaging findings revealed the presence of an eccentric vascular pedicle along the dorsal aspect of the tumor in 8 of the 10 patients (eccentric vessel sign), a distinctive finding that has not previously been reported with this tumor and may help improve the accuracy of imaging-based diagnosis. In all cases, a gross-total resection was performed, with resolution of symptoms in most of the cases.

Purpose Imaging changes in the pituitary volume during pregnancy remains scantly researched. This study set out to assess the differences in total, anterior, and posterior pituitary volume in pregnant women compared to nulliparous and post-partum women.Materials and Methods A retrospective review was completed of women that had undergone MRI imaging of the brain. Patients were divided into three cohorts: pregnant, nulliparous, and post-partum (defined as being within 12 months of delivery). Anterior and posterior pituitary volumes were manually measured.Results 171 patients were included, of which 68 were pregnant, 52 were post-partum, and 51 were nulliparous. The average anterior (621.0 ± 171.6 mm3) and total (705.4 ± 172.2 mm3) pituitary volumes were significantly larger in pregnant patients than nulliparous women (522.6 ± 159.8 mm3and 624.5 ± 163.7 mm3, respectively) (p= .002 and p= .01, respectively). The posterior pituitary volume was significantly smaller in pregnant women (84.4 ± 32.9 mm3) compared to both post-partum (101.2 ± 42.0 mm3) and nulliparous (102.0 ± 46.1 mm3) women (p= .02 for both).Conclusions The anterior and total pituitary volumes are significantly larger during pregnancy persisting into the post-partum period. The posterior pituitary volume, conversely, decreases during pregnancy, and returns to its normal size in the post-partum period.

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.

Superficial siderosis refers to hemosiderin deposition along the pial surface of the brain and spinal cord. It results from chronic and repetitive low-grade bleeding into the subarachnoid space. Dural tears are a common cause of superficial siderosis. Although such tears typically occur in the spine, dural tears can also occur in the posterior fossa. In many cases, posterior fossa dural tears are iatrogenic, and patients may present with neuroimaging evidence of postoperative pseudomeningoceles. We present a case of superficial siderosis caused by a persistent posterior fossa dural leak. The patient presented with superficial siderosis 30 years after a Chiari I malformation repair. A pinhole-sized dural tear was identified preoperatively using computed tomography cisternography. The dural defect was successfully repaired. An additional small tear that was not seen on imaging was also identified at surgery and successfully repaired.

Peripheral neuropathies are a recognized complication of labor in the post-partum period. Herein, we describe an uncommon presentation of sciatic mononeuropathy due to ischiofemoral impingement during labor. A 29-year-old, gravida 4 para 2, female presented post-partum with acute left lower limb paresthesia and left foot drop, following spontaneous vaginal delivery of twins. Neurological examination demonstrated no activation of the left sciatic-innervated muscles and sensory loss in the same distribution. Electromyography (EMG) demonstrated an acute complete left sciatic mononeuropathy. MRI of the lumbosacral plexus and sciatic nerve showed a narrowed quadratus femoris space with mild edema of the muscle, consistent with ischiofemoral impingement syndrome. In addition, there was flattening of the sciatic nerve as it passed through the ischiofemoral space. She was treated conservatively, and at 7-month follow-up, there was marked improvement in muscle strength with ongoing sensory impairment. Repeat EMG demonstrated reinnervation in all sciatic-innervated muscles. This case highlights the risk of a sciatic mononeuropathy secondary to ischiofemoral impingement in the peripartum setting. Future studies are needed to determine if women with a narrow ischiofemoral space at baseline are at increased risk for peripheral nerve injury during labor.

BackgroundWe report outcomes of spontaneous intracranial hypotension (SIH) patients who underwent transvenous embolization of cerebrospinal fluid-venous fistulas (CSFVFs) confirmed on digital subtraction myelography (DSM) performed at our institution.MethodsThis is a retrospective evaluation of a prospectively collected database of SIH patients who underwent transvenous embolization of CSFVFs. Only patients who had fistulas confirmed on DSM performed at our institution were included. All patients had a baseline MRI and an MRI performed at least 90 days post-embolization, as well as clinical evaluation using the six item Headache Impact Test (HIT-6) and the Patient Global Impression of Change (PGIC) scales. Paired t-test was used to report changes in Bern MRI scores and HIT-6 scores at follow-up.Results40 patients were included (29 female, 11 male). Mean age was 57.4±10.3 years. Mean Bern score improved from 5.7±3.0 at baseline to 1.3±2.0 at follow-up (p<0.0001). Mean HIT-6 score at baseline was 67.2±11.1 and at follow-up was 41.5±10.1 (p<0.0001). Median PGIC was 1, with 36 patients (90.0%) reporting at least minimal improvement and 32 patients (82.5%) reporting much or very much improvement. Complications included persistent local site pain in 12 patients (30%), suspected rebound intracranial hypertension requiring medical intervention in 7 patients (17.5%), and asymptomatic tiny Onyx emboli to the lungs in 3 patients (7.5%).ConclusionsTransvenous embolization of CSFVFs using Onyx is safe and effective, resulting in significant improvement in headache and overall clinical outcomes in nearly 90% of patients, and substantial improvements in brain MRI abnormalities.

Torus mandibularis is a benign osseous overgrowth arising from the lingual surface of the mandible. It is a common, incidental finding on imaging due to its relatively high prevalence. In the majority of cases, mandibular tori are asymptomatic. We report a novel presentation of a giant torus mandibularis causing bilateral obstruction of the submandibular ducts and consequent sialadenitis. Our patient presented with progressive pain centered in the floor of his mouth and had bilateral submandibular glandular enlargement on exam. Computed tomography showed a giant right torus mandibularis, which was causing obstruction and dilation of the bilateral submandibular ducts. Although conservative management was attempted, he ultimately underwent surgical resection of his torus with symptomatic improvement. This patient highlights a novel complication of torus mandibularis and illustrates successful treatment. Though not previously described, this complication may be underreported and should be considered in the appropriate clinical setting.

ObjectiveCochleovestibulopathy is a distinguishable paraneoplastic phenotype. In this study, we evaluate clinical presentation, serological/cancer associations and outcomes of paraneoplastic cochleovestibulopathy.MethodsRetrospective chart review of patients with hearing impairment and/or vestibulopathy who underwent serological evaluations for paraneoplastic antibodies between January 2007 and February 2021 was performed.ResultsTwenty-six patients were identified (men, n=23; median age, 45 years, range: 28–70). Biomarkers detected included: KLHL11-IgG (n=20, 77% (coexisting LUZP4-IgG, n=8)), ANNA1-IgG (n=3, 12%), amphiphysin-IgG (n=2, 8%) and LUZP4-IgG (n=1, 4%). Most common neoplastic association was testicular/extra-testicular seminoma (n=13, 50%). Hearing impairment (bilateral, 62%) was present in all patients. Fifteen patients (58%) had cochleovestibular dysfunction as their initial presentation before rhombencephalitis/encephalomyelitis manifestations (hearing loss, four; acute vertigo, eight; both, three). Brain MRI demonstrated internal auditory canal enhancement in four patients. Audiometry commonly revealed severe-profound bilateral sensorineural hearing loss. Most patients had a refractory course despite immunotherapy and/or cancer treatment.ConclusionCochleovestibulopathy commonly presents with rapidly progressive bilateral hearing loss and/or acute vertigo. However, in some patients, these symptoms present along with or following brainstem/cerebellar manifestations. KLHL11-IgG and seminoma are the most common serological and cancer associations, respectively. Recognition of this phenotype may aid in earlier diagnosis of paraneoplastic autoimmunity and associated cancer.

Tolosa–Hunt syndrome is characterized by unilateral retro-orbital headaches and cranial nerve palsies, usually involving cranial nerves III–VI. It is rare for other cranial nerves to be involved, although this has previously been reported. We report a 19-year-old woman presenting with typical features of Tolosa–Hunt syndrome but ultimately developing bilateral facial nerve palsies and enhancement of both facial nerves on magnetic resonance imaging. The patient presented with unilateral retro-orbital headaches and palsies of cranial nerves III–VI. She was diagnosed with Tolosa–Hunt syndrome but was non-compliant with her corticosteroid treatment due to side effects. She returned with progressive left followed by right facial nerve palsy. Her corresponding follow-up magnetic resonance imaging scans showed sequential enhancement of the left and right facial nerves. She ultimately had clinical improvement with IV methylprednisolone. To our knowledge, Tolosa–Hunt syndrome associated with bilateral facial nerve palsy and corroborative facial nerve enhancement on magnetic resonance imaging has not previously been described. Moreover, our patient’s clinical course is instructive, as it demonstrates that this atypical presentation of Tolosa–Hunt syndrome can indeed respond to corticosteroid treatment and should not be mistaken for other entities such as Bell’s palsy.

A 69-year-old female presented with subacute onset ascending weakness and paraesthesias. She was initially diagnosed with Guillain–Barré syndrome (GBS) based on her clinical presentation and cerebrospinal fluid (CSF) analysis showing albuminocytological dissociation. However, she was later found to have anti-neuronal nuclear antibody 1 (ANNA-1/anti-Hu)-positive CSF and was subsequently diagnosed with small-cell lung cancer. Her neurological symptoms were ultimately attributed to ANNA-1/anti-Hu-associated paraneoplastic polyneuropathy. During the course of her evaluation, she had magnetic resonance imaging findings of dorsal predominant cauda equina nerve root enhancement, which has not been previously described. The only previously reported case of cauda equina enhancement due to ANNA-1-associated polyneuropathy described ventral predominant findings. The distinction between ventral and dorsal enhancement is important, since it suggests that different patterns of nerve root involvement may be associated with this paraneoplastic syndrome. Therefore, ANNA-1-associated paraneoplastic inflammatory polyneuropathy can be considered in the differential diagnosis of cauda equina nerve root enhancement with ventral and/or dorsal predominance. This can potentially be helpful in differentiating ANNA-1 polyneuropathy from GBS, which classically has ventral predominant enhancement.

Stem cell treatment outside of studied and approved medical indications can have unforeseen adverse consequences. Here, we present a 74-year-old male that underwent such therapy. The patient presented to our institution with progressive lower extremity weakness and urinary incontinence. He had previously undergone intrathecal stem cell therapy in Moscow, Russia for weakness and fatigue. Magnetic resonance imaging of his thoracic and lumbar spine showed marked enlargement of the cauda equina nerve roots and abnormal mass-like soft tissue involving the thoracolumbar thecal sac. Surgical biopsy of the intrathecal soft tissue showed polyclonal lymphocytic and glial cell proliferation. The patient’s symptoms did not improve with medical treatment or radiation, and he is currently under observation after multidisciplinary evaluation. Our patient’s experience illustrates one of the potential risks of “stem cell tourism” and exemplifies the imaging and histopathologic features of this rare entity. We also compare our patient’s treatment with other similar examples of stem cell treatments in our institution and others. These have had a wide spectrum of results. In some instances, intrathecal stem cells have caused abnormal imaging findings without any associated patient symptoms. In extreme examples, however, stem cell treatments have resulted in central nervous system neoplasms. Our patient’s lesion is quite unique, with only one similar lesion having been previously published.

Intrathecal blood after a percutaneous epidural blood patch is a known complication, one that has been previously attributed to inadvertent needle tip position in the subarachnoid space. We present two cases with imaging confirmation of an alternative mechanism, one that includes blood transferring from the epidural space to the subarachnoid space through a pre-existing dural defect.

CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. These fistulas usually occur without any preceding major trauma, surgery, or other iatrogenic cause. Occasionally, patients have a history of minor trauma, though such cases are usually still considered spontaneous. Little is known about predisposing factors that cause patients to develop spontaneous CVFs. Most patients with CVFs have multiple meningeal diverticula on spine imaging, and fistulas usually arise in association with a diverticulum. In the vast majority of cases, the culprit diverticulum from which the CVF arises is atraumatic in origin, presumably on the spectrum of normal variation in spinal anatomy. Here, we present two cases of CVFs that arose in association with posttraumatic pseudomeningoceles. To our knowledge, this phenomenon has not yet been reported, and it potentially represents a novel etiology for CVFs that furthers understanding of their pathogenesis.

Epidural steroid injections are commonly performed using fluoroscopic or CT guidance. With both modalities, the injection of contrast material is necessary before steroid administration to ensure adequate epidural flow and exclude non-epidural flow. While fluoroscopic guidance is conventional, CT is utilized at some centers and can be particularly helpful in the setting of challenging or postoperative anatomy. It is important for proceduralists to be adept at evaluating contrast media flow patterns under both modalities. The goal of this review article is to describe and provide examples of epidural and non-epidural flow patterns on both conventional fluoroscopy and CT. Specific non-epidural patterns discussed include intrathecal flow, intradural/subdural flow, vascular uptake, flow into the retrodural space of Okada, inadvertent facet joint flow, and intradiscal flow.

Dilated perivascular spaces (PVSs) are common and easily recognized on imaging. However, rarer giant tumefactive PVSs (GTPVSs) can have unusual multilocular cystic configurations, and are often confused for other pathologic entities, including neoplasms, cystic infarctions, and neuroepithelial cysts. Because GTPVSs are scarcely encountered and even more infrequently operated upon, many radiologists are unaware of the imaging and pathologic features of these lesions. Here, a case of a resected GTPVS is presented, highlighting both its radiologic and histologic characteristics, and discussing how such lesions can be differentiated from their closest mimickers on imaging.

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 (pvalues 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.

Background As the myriad clinical and radiographic presentations of spontaneous intracranial hypotension are increasingly recognized, disease prevalence appears to rise. True incidence data remain insufficient. We sought to calculate the incidence of spontaneous intracranial hypotension among the residents of Olmsted County, Minnesota.Methods Our institution is a quaternary care center for spontaneous intracranial hypotension evaluation and provides primary neurologic care for local residents. All patients who were evaluated at our institution from 2019 to 2021 for spontaneous intracranial hypotension were reviewed, and cases of spontaneous intracranial hypotension with advanced imaging work-up using digital subtraction myelography or dynamic computed tomography myelography were identified. Patients who were residents of Olmsted County were identified.Results Fourteen patients with spontaneous intracranial hypotension were identified in Olmsted County during the study period, all of whom were adults and underwent our institution's standard spontaneous intracranial hypotension work-up. In Olmsted County, the incidence of spontaneous intracranial hypotension was 3.8 per 100,000 adult population, including 3.2 per 100,000 adult females and 2.5 per 100,000 adult males. Seven of 14 patients (50%) had a cerebrospinal fluid-venous fistula.Conclusion This study uniquely presents the incidence rate of spontaneous intracranial hypotension in the general population of Olmsted County, Minnesota. Spontaneous intracranial hypotension is more common in women than men and has an overall incidence roughly equivalent to that of aneurysmal subarachnoid hemorrhage in Olmsted County, a widely known neurologic condition. Approximately half the cases of spontaneous intracranial hypotension are due to cerebrospinal fluid-venous fistulas, which generally require specialty expertise for diagnosis and treatment.

Transvenous Onyx embolization was recently described as an effective treatment of spontaneous intracranial hypotension caused by CSF-venous fistulas. Patients with CSF-venous fistulas can present with a wide spectrum of clinical and imaging findings, sometimes including spontaneous subdural hematomas, subdural hygromas, or a combination of both. Here, we describe four patients with spontaneous intracranial hypotension complicated by subdural fluid collections caused by CSF-venous fistulas. The patients were treated with transvenous Onyx embolization of their CSF-venous fistulas and transarterial particle embolization of the bilateral middle meningeal arteries, with both procedures performed in a single treatment session. All four patients had clinical improvement and decreased size or resolution of their subdural fluid collections. Based on our findings, we believe that middle meningeal embolization could be a useful adjunct to CSF-venous fistula embolization. A case-control study comparing patients who did or did not undergo middle meningeal embolization will be necessary to validate this supposition.

Background Computed tomography (CT) angiography collateral score (CTA-CS) is an important clinical outcome predictor following mechanical thrombectomy for ischemic stroke with large vessel occlusion (LVO). The present multireader study aimed to evaluate the performance of e-CTA software for automated assistance in CTA-CS scoring.Materials and Methods Brain CTA images of 56 patients with anterior LVO were retrospectively processed. Twelve readers of various clinical training, including junior neuroradiologists, senior neuroradiologists, and neurologists graded collateral flow using visual CTA-CS scale in two sessions separated by a washout period. Reference standard was the consensus of three expert readers. Duration of reading time, inter-rater reliability, and statistical comparison of readers’ performance metrics were analyzed between the e-CTA assisted and unassisted sessions.Results e-CTA assistance resulted in significant increase in mean accuracy (58.6% to 67.5%, p = 0.003), mean F1 score (0.574 to 0.676, p = 0.002), mean precision (58.8% to 68%, p = 0.007), and mean recall (58.7% to 69.9%, p = 0.002), especially with slight filling deficit (CTA-CS 2 and 3). Mean reading time was reduced across all readers (103.4 to 59.7 s, p = 0.001), and inter-rater agreement in CTA-CS assessment was increased (Krippendorff's alpha 0.366 to 0.676). Optimized occlusion laterality detection was also noted with mean accuracy (92.9% to 96.8%, p = 0.009).Conclusion Automated assistance for CTA-CS using e-CTA software provided helpful decision support for readers in terms of improving scoring accuracy and reading efficiency for physicians with a range of experience and training backgrounds and leading to significant improvements in inter-rater agreement.

We present an updated ultrafast dynamic computed tomography myelography technique that can be used for the localization of spontaneous spinal cerebrospinal fluid leaks in the setting of spontaneous intracranial hypotension. This has over twice the temporal resolution of previously described techniques at the same radiation dose output.

Background and purpose Radiation therapy is an important component of treatment in patients with malignancies of the head, neck, and spine. However, radiation to these regions has well-known potential side effects, many of which can be encountered on imaging. In this manuscript, we review selected radiographic manifestations of therapeutic radiation to the head, neck, and spine that may be encountered in the practice of radiology.Methods We conducted an extensive literature review of known complications of radiation therapy in the head, neck, and spine. We excluded intracranial and pulmonary radiation effects from our search. We selected complications that had salient, recognizable imaging findings. We searched our imaging database for illustrative examples of these complications.Results Based on our initial literature search and imaging database review, we selected cases of radiation-induced tumors, radiation tissue necrosis (osteoradionecrosis and soft tissue necrosis), carotid stenosis and blowout secondary to radiation, enlarging thyroglossal duct cysts, radiation myelopathy, and radiation-induced vertebral compression fractures.Conclusions We describe the clinical and imaging features of selected sequelae of radiation therapy to the head, neck, and spine, with a focus on those with characteristic imaging findings that can be instrumental in helping to make the diagnosis. Knowledge of these entities and their imaging findings is crucial for accurate diagnosis. Not only do radiologists play a key role in early detection of these entities, but many of these entities can be misinterpreted if one is not familiar with them.