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Background and Purpose: CSF leaks of the skull base and spine share a common process of CSF volume loss, and yet only the latter has been associated with spontaneous intracranial hypotension (SIH). Despite published claims that only spinal leaks cause SIH, no prior studies have evaluated brain MR imaging in patients with skull base leaks for findings associated with SIH, such as dural enhancement. The purpose of our study was to use a validated brain MR imaging scoring system to evaluate patients with skull base CSF leaks for findings associated with SIH., Materials and Methods: We included patients with confirmed skull base CSF leaks and contrast-enhanced preoperative brain MRI. The preoperative MR images were reviewed for findings associated with SIH by using the Bern score. Patient age, presenting symptoms and their duration, and leak site were also recorded., Results: Thirty-one patients with skull base CSF leaks were included. Mean Bern score was 0.9 (range 0-4, standard deviation 1.1), and only 1 patient (3%) had dural enhancement. Mean age was 53 years (range 18-76). Mean symptom duration was 1.3 years, with 22 patients presenting within 1 year of symptom onset. Twenty-three patients (74.2%) had intraoperative confirmation of leak from the middle cranial fossa, involving the temporal bone, while 7 (22.6%) had leaks from the anterior skull base. One patient, who had dural enhancement, had an infratentorial CSF leak along the petrous segment of the internal carotid artery., Conclusions: Our study provides further evidence that skull base and spinal CSF leaks represent distinct pathophysiologies and present with different brain MRI findings., (© 2024 by American Journal of Neuroradiology.)

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.

Background and Purpose: Spontaneous intracranial hypotension is a condition resulting from a leak of CSF from the spinal canal arising independent of a medical procedure. Spontaneous intracranial hypotension can present with normal brain MR imaging findings and nonspecific symptoms, leading to the underdiagnosis in some patients and unnecessary invasive myelography in others who are found not to have the condition. Given the likelihood that spontaneous intracranial hypotension alters intracranial biomechanics, the goal of this study was to evaluate MR elastography as a potential noninvasive test to diagnose the condition., Materials and Methods: We performed MR elastography in 15 patients with confirmed spontaneous intracranial hypotension from September 2022 to April 2023. Age, sex, symptom duration, and brain MR imaging Bern score were collected. MR elastography data were used to compute stiffness and damping ratio maps, and voxelwise modeling was performed to detect clusters of significant differences in mechanical properties between patients with spontaneous intracranial hypotension and healthy control participants. To evaluate diagnostic accuracy, we summarized each examination by 2 spatial pattern scores (one each for stiffness and damping ratio) and evaluated group-wise discrimination by receiver operating characteristic curve analysis., Results: Patients with spontaneous intracranial hypotension exhibited significant differences in both stiffness and damping ratio (false discovery rate-corrected, Q < 0.05). Pattern analysis discriminated patients with spontaneous intracranial hypotension from healthy controls with an area under the curve of 0.97 overall, and the area under the curve was 0.97 in those without MR imaging findings of spontaneous intracranial hypotension., Conclusions: Results from this pilot study demonstrate MR elastography as a potential imaging biomarker and a noninvasive method for diagnosing spontaneous intracranial hypotension, including patients with normal brain MR imaging findings., (© 2024 by American Journal of Neuroradiology.)

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.

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.

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. [ABSTRACT FROM AUTHOR]

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented. [ABSTRACT FROM AUTHOR]

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]

Klippel-Trenaunay syndrome (KTS) is associated with a wide variety of vascular and neurologic abnormalities, including venolymphatic malformations. A recent report postulated that patients with KTS may also be predisposed to spontaneous intracranial hypotension. We reviewed brain magnetic resonance imaging from 67 patients with KTS and unexpectedly noted findings of cerebrospinal fluid (CSF) hypotension in 4 of them. Patients included a 39-year-old woman with episodic orthostatic headaches, a 62-year-old woman with orthostatic headaches and light-headedness, a 14-year-old girl with a history of headaches for years, and an asymptomatic 20-year-old man. All 4 patients had known KTS, and all had brain magnetic resonance imaging done during their evaluation showing evidence of CSF hypotension. The first 2 patients also had spine imaging demonstrating paraspinal and/or epidural venolymphatic malformations. The second patient had a meningeal diverticulum and underwent surgical repair with intraoperative evidence of a CSF leak. Patients with KTS have an increased incidence of CSF hypotension. While it is possible that intrinsic dural weakness may be responsible for this association, we hypothesize that these patients are also predisposed to developing CSF venous fistulas. Paraspinal and epidural venolymphatic malformations have been described in multiple patients with CSF venous fistulas. Such malformations were present in 2 of our 4 patients who underwent spine imaging. Patients with KTS with orthostatic headaches may benefit from brain and spine magnetic resonance imaging to assess for evidence of CSF hypotension and venolymphatic malformations. Decubitus digital subtraction myelography may also have a role in these patients if CSF venous fistulas are suspected. [ABSTRACT FROM AUTHOR]

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. 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. 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. [ABSTRACT FROM AUTHOR]

Background: Different clinical syndromes can arise from Alzheimer's disease (AD) neuropathology, including dementia of the Alzheimer's type (DAT), logopenic primary progressive aphasia (lvPPA), and posterior cortical atrophy (PCA).Objective: To assess similarities and differences in patterns of white matter tract degeneration across these syndromic variants of AD.Methods: Sixty-four subjects (22 DAT, 24 lvPPA, and 18 PCA) that had diffusion tensor imaging and showed amyloid-β deposition on PET were assessed in this case-control study. A whole-brain voxel-based analysis was performed to assess differences in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity across groups.Results: All three groups showed overlapping diffusion abnormalities in a network of tracts, including fornix, corpus callosum, posterior thalamic radiations, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus. Subtle regional differences were also observed across groups, with DAT particularly associated with degeneration of fornix and cingulum, lvPPA with left inferior fronto-occipital fasciculus and uncinate fasciculus, and PCA with posterior thalamic radiations, superior longitudinal fasciculus, posterior cingulate, and splenium of the corpus callosum.Conclusion: These findings show that while each AD phenotype is associated with degeneration of a specific structural network of white matter tracts, striking spatial overlap exists among the three network patterns that may be related to AD pathology. [ABSTRACT FROM AUTHOR]

Objectives: The logopenic variant of primary progressive aphasia is an atypical clinical variant of Alzheimer’s disease which is typically characterized by left temporoparietal atrophy on magnetic resonance imaging and hypometabolism on F-18 fluorodeoxyglucose positron emission tomography. We aimed to characterize and compare patterns of atrophy and hypometabolism in logopenic primary progressive aphasia, and determine which brain regions and imaging modality best differentiates logopenic primary progressive aphasia from typical dementia of the Alzheimer’s type. Methods: A total of 27 logopenic primary progressive aphasia subjects underwent fluorodeoxyglucose positron emission tomography and volumetric magnetic resonance imaging. These subjects were matched to 27 controls and 27 subjects with dementia of the Alzheimer’s type. Patterns of atrophy and hypometabolism were assessed at the voxel and region-level using Statistical Parametric Mapping. Penalized logistic regression analysis was used to determine what combinations of regions best discriminate between groups. Results: Atrophy and hypometabolism was observed in lateral temporoparietal and medial parietal lobes, left greater than right, and left frontal lobe in the logopenic group. The logopenic group showed greater left inferior, middle and superior lateral temporal atrophy (inferior p = 0.02; middle p = 0.007, superior p = 0.002) and hypometabolism (inferior p = 0.006, middle p = 0.002, superior p = 0.001), and less right medial temporal atrophy (p = 0.02) and hypometabolism (p<0.001), and right posterior cingulate hypometabolism (p<0.001) than dementia of the Alzheimer’s type. An age-adjusted penalized logistic model incorporating atrophy and hypometabolism achieved excellent discrimination (area under the receiver operator characteristic curve = 0.89) between logopenic and dementia of the Alzheimer’s type subjects, with optimal discrimination achieved using right medial temporal and posterior cingulate hypometabolism, left inferior, middle and superior temporal hypometabolism, and left superior temporal volume. Conclusions: Patterns of atrophy and hypometabolism both differ between logopenic primary progressive aphasia and dementia of the Alzheimer’s type and both modalities provide excellent discrimination between groups. [ABSTRACT FROM AUTHOR]