Giant Arachnoid Granulations: Diagnostic Workup and Characterization in Three Symptomatic Adults.

Giant arachnoid granulations (GAGs) are poorly investigated. Here, we document clinical findings associated with five new GAGs and illustrate the anatomical composition of these structures as well as diagnostic considerations in three symptomatic adults. The GAGs ranged from 1.1 to 3.6 cm (mean, 2.2 cm) in maximum dimension and manifested in middle-aged individuals who presented with long-standing brain mass and/or chronic headache. On imaging examinations, the tissues appeared as irregular parasagittal and/or perisinus structures that demonstrated heterogeneous internal elements. The GAGs abutted dura, extended through calvarial marrow spaces, and impinged on dural venous sinuses, causing their stenosis. The histologic workup of two GAG specimens resected from separate individuals revealed central collagen with pronounced internal vascular proliferation. One specimen additionally exhibited reactive changes within the lesion, including venous thrombosis, hemorrhage, and conspicuous inflammation. The salient immune component consisted of a foam cell-rich infiltrate that obstructed subcapsular and internal sinusoidal GAG spaces. Within this specimen, meningothelial hyperplasia was also appreciated. Notably, proliferated lymphatic vascular elements were additionally observed within the structure, extending into deep central collagen regions and engulfing many extravasated erythrocytes in the subcapsular space. In both surgically treated patients, symptoms resolved completely following resection. This report is the first to definitively depict reactive vascular and immunological changes within GAGs that were clinically associated with headache. The frequency of reactive changes within these meningeal structures is unclear in the literature, as GAGs are rarely sampled and investigated. Further systematic analyses are warranted to elucidate the causes and consequences of GAG genesis and their roles in physiology and disease states.

Radiological abnormalities in progressive multifocal leukoencephalopathy: Identifying typical and atypical imaging patterns for early diagnosis and differential considerations.

Progressive multifocal leukoencephalopathy (PML) is a rare viral central nervous system (CNS) demyelinating disease primarily associated with a compromised immune system. PML is seen mainly in individuals with human immunodeficiency virus, lymphoproliferative disease, and multiple sclerosis. Patients on immunomodulators, chemotherapy, and solid organ or bone marrow transplants are predisposed to PML. Recognition of various PML-associated typical and atypical imaging abnormalities is critical for early diagnosis and differentiating it from other conditions, especially in high-risk populations. Early PML recognition should expedite efforts at immune-system restoration, allowing for a favorable outcome. This review aims to provide a practical overview of radiological abnormalities in PML patients and address differential considerations.

Finding MRI features to obviate the need of repeat spinal biopsies in clinically suspected persistent or recurrent spinal osteomyelitis.

Purpose: The aim of this study was to determine magnetic resonance imaging (MRI) features that could help differen-tiate the bone destruction due to persistent/recurrent spine infection from worsening bone destruction due to mechanical factors, which could help obviate the need for repeat spine biopsy. Material and methods: A retrospective study was performed on selected subjects who were more than 18 years of age, were diagnosed with infectious spondylodiscitis, underwent at least 2 spinal interventions for the diagnosis at the same level, and had MRI prior to each image-guided intervention. Both MRI studies were analysed for vertebral body changes, paravertebral collections, epidural thickening and collections, bone marrow signal changes, loss of vertebral body height, abnormal signal in intervertebral disc, and loss of disc height. Results: We observed that worsening of changes in paravertebral and epidural soft tissue were statistically more significant predictors of recurrent/persistent spine infection (p< 0.05). However, worsening destruction of vertebral body and intervertebral disc, abnormal vertebral marrow signal changes, and abnormal signal in intervertebral disc did not necessarily indicate worsening infection or recurrence. Conclusions: In patients of infectious spondylitis with suspected recurrence, the most common and pronounced MRI findings of worsening osseous changes can be deceiving and can result in negative repeat spinal biopsy. Changes in paraspinal and epidural soft tissues are more helpful in identifying the cause of worsening bone destruction. Correlation with clinical examination, inflammatory markers, and observing soft tissue changes on follow-up MRI is a more reliable way to identify patients who may benefit from repeat spine biopsy.

Chronic inflammatory demyelinating polyneuropathy: A unique case of chronic disease with atypical features.

We present a unique case of diffusely extensive Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Typically affecting the peripheral nervous system and manifesting with muscle weakness, breakdown or paresthesia, we present a case that additionally demonstrates; cranial nerve involvement, central nervous system parenchymal lesions, and chronic osseous remodeling of the nerve tracts. Cranial nerve involvement to this extent has only been described in one other case report to our knowledge. Central nervous system parenchymal lesions are extremely rare in CIDP and no discrete discussion about osseous remodeling has been presented, thus far, in the literature. The findings illustrated in this case may spur further understanding of imaging characteristics most associated with chronic CIDP disease and care measures that could help stratify patients most at risk for severe symptomologies.

Striatal dominant lupus encephalitis-Is it vasculitis or an autoimmune process? Literature review & new case report with vessel wall imaging.

Neurological and psychiatric symptoms are highly prevalent in the initial manifestation of systemic lupus erythematosus (SLE) and is classified as neuropsychiatric systemic lupus erythematosus (NPSLE). Despite the high prevalence rate of this condition, it is still very poorly understood and often delayed in its diagnosis due to its variety in clinical manifestations. For our case, an eighteen-year-old male who was recently diagnosed with SLE presented with progressive confusion, visual and auditory hallucinations, in addition to high fevers, diarrhea, abdominal and flank pain. Upon initial presentation, he was treated for sepsis while trying to identify a source of infection. However, with the help of laboratory tests like CSF analysis and autoantibody serum studies as well as neuroradiologic imaging, we were able to rule out infectious causes and diagnose our patient with lupus induced striatal encephalitis. We present the first case of striatal encephalitis with vessel wall imaging to ultimately rule out lupus associated vasculitis. The importance of MRI imaging and identification of specific patterns associated with autoimmune encephalitis allowed rapid diagnosis and initiated immediate treatment in the hopes of reducing long term affects from neuroinflammation in our young patient.

Retrospective Comparative Analysis of Fluoroscopic-Guided Lumbar Puncture in the Routine Prone Versus Lateral Decubitus Position.

OBJECTIVE: We sought to investigate patient outcomes such as success rate, fluoroscopy time, and radiation dose for fluoroscopic-guided lumbar puncture procedures performed in the prone position versus the lateral decubitus (LD) position. METHODS: Retrospective chart analysis was performed at a single institution from 2013 to 2019. Cases were separated by performance in the prone or lateral decubitus positions. Data collected include patient characteristics, fluoroscopy time, radiation dose (DAP), puncture level, indication, opening pressure, and success rate. Exclusion criteria include trainee participation and procedures where positioning was unspecified. Mean fluoroscopy time, DAP, and procedure success rate were calculated and compared between groups. RESULTS: Mean fluoroscopy time (min) was 0.97 and 1.07 in the LD and prone groups respectively (p = 0.21). Mean DAP (mGy) was 43.18 and 42.06 in the LD and prone groups respectively (p = 0.38). Success rate was 98.3% and 89.1% in the LD and prone groups respectively (p = 0.04). Room time (minutes) was 64.46 and 77.77 in the LD and prone groups respectively (p = 0.04). CONCLUSION: Our study found no statistically significant difference in terms of fluoroscopic time or radiation dose when comparing fluoroscopic-guided lumbar punctures in the prone versus lateral decubitus positions. Further analysis did show a statistically significant increased success rate and a shorter room time for the lateral decubitus position.

Hypervascular vestibular schwannoma: A case report and review of the literature.

Vestibular schwannomas, also known as acoustic neuromas, are benign tumors that arise from Schwann cells near the transition from glial cells to Schwann cells. While most vestibular schwannomas are hypovascular tumors, a small percentage constitute the hemorrhagic and/or hypervascular vestibular schwannomas (HVS) subtype. We describe a case of a 36-year-old female who presented with nausea, vomiting, and an acute decrease in vision in her right eye. Computed tomography of the head demonstrated a hemorrhagic lesion in the right hemisphere with evidence of ventricular effacement. Follow-up magnetic resonance imaging revealed a mass in the right cerebellopontine angle that was hypointense on T1-weighted imaging and mild hyperintense heterogeneous signal on T2-weighted imaging, suggestive of a hemorrhagic vestibular schwannoma. It is important for radiologists to recognize the unique clinical and radiological features of HVS in the initial diagnostic assessment of cerebellopontine angle tumors and to distinguish it from common (hypovascular) vestibular schwannomas and other related pathologies. A preoperative diagnosis of HVS allows clinicians to become familiar with the unique characteristics of the tumor and to devise a feasible operative strategy prior to surgical resection.

Clinical, Pathologic, and Radiologic Features of Orbital Solitary Fibrous Tumors and Meningiomas.

A wide variety of benign and malignant tumors can arise from different structures in the orbital and peri-orbital area, affecting the eye and the optic nerve. This spectrum of tumors includes primary and metastatic carcinomas, lymphomas, melanomas, soft tissue tumors, and primary tumors of the retina, optic disc, and optic nerve. These also extend to relatively rare entities such as solitary fibrous tumor and meningioma of the orbit and optic nerve, which can present with very similar clinical and radiologic features, although the tumor grades, treatment plans, and outcomes can vary widely. In this report, we present two clinical cases of solitary fibrous tumor [central nervous system (CNS) World Health Organization (WHO) grade 2 and 3) and compare their clinical presentation, radiologic and histologic features, treatment, and clinical outcomes to a group of three orbital meningiomas (CNS WHO grade 1 and 2). In the context of these five cases of orbital lesions, we review the current clinical, pathologic, and radiologic literature on orbital tumors, focusing primarily on solitary fibrous tumors and meningiomas, along with an expanded discussion on the diagnostic criteria of both entities, as well as the treatment and prognosis of these lesions.

Case 284: Posterior Quadrantic Dysplasia.

History A 36-year-old left-handed woman with a history of developmental delay and medical refractory seizures since birth most recently presented with continuous simple partial seizures and occasional breakthrough complex partial seizures with postictal migraines. These were described as the patient "becoming pale with sinking to the floor and staring for approximately 1 minute with confusion thereafter." The patient had years of reported seizure freedom until 2010 when she was evaluated for intractable headaches, and electroencephalography revealed her focal subclinical status. At that time, ambulatory electroencephalography findings showed asymmetric left parietal-occipital high-amplitude spike-and-wave discharges in her best awake and alert state. Since that time, the patient developed and continues to have complex partial seizures every 2-3 months that are persistent despite the implementation of several medical regimens. At the time of recent presentation, the patient initially underwent unenhanced head CT in the emergency department followed by unenhanced MRI of the brain due to increased seizure activity at the patient's group home despite continued compliance with her antiepileptic regimen. Contrast material-enhanced imaging was not available at the time of recent presentation, so comparison was made with gadolinium-enhanced brain MRI performed approximately 9 years earlier.

Case 284.

History A 36-year-old left-handed woman with a history of developmental delay and medical refractory seizures since birth most recently presented with continuous simple partial seizures and occasional breakthrough complex partial seizures with postictal migraines. These were described as the patient "becoming pale with sinking to the floor and staring for approximately 1 minute with confusion thereafter." The patient had years of reported seizure freedom until 2010 when she was evaluated for intractable headaches, and electroencephalography revealed her focal subclinical status. At that time, ambulatory electroencephalography findings showed asymmetric left parietal-occipital high-amplitude spike-and-wave discharges in her best awake and alert state. Since that time, the patient developed and continues to have complex partial seizures every 2-3 months that are persistent despite the implementation of several medical regimens. At the time of recent presentation, the patient initially underwent unenhanced head CT in the emergency department followed by unenhanced MRI of the brain due to increased seizure activity at the patient's group home despite continued compliance with her antiepileptic regimen. Contrast material-enhanced imaging was not available at the time of recent presentation, so comparison was made with gadolinium-enhanced brain MRI performed approximately 9 years earlier (Figs 1-5).

Cost-Effectiveness of Computed Tomography Angiography in Management of Tiny Unruptured Intracranial Aneurysms in the United States.

Background and Purpose- Our study aims to evaluate the cost-effectiveness of computed tomography angiography (CTA) for surveillance of tiny unruptured intracranial aneurysms and the impact of CTA radiation-induced brain tumor on the overall effectiveness of CTA. Methods- A Markov decision model was constructed from a societal perspective starting with patients 30-, 40-, or 50-year-old, with incidental detection of unruptured intracranial aneurysm ≤3 mm and no prior history of subarachnoid hemorrhage. Five different management strategies were assessed (1) annual CTA surveillance, (2) biennial CTA, (3) CTA follow-up every 5 years, (4) coiling and subsequent magnetic resonance imaging follow-up, and (5) annual CTA surveillance for the first 2 years, followed by every 5-year CTA follow-up. Probabilistic, 1-way, and 2-way sensitivity analyses were performed. Results- The base case calculation shows every 5-year CTA follow-up to be the most cost-effective strategy, and the conclusion remains robust in probabilistic sensitivity analysis. It remains the dominant strategy when the annual rupture risk of nongrowing unruptured intracranial aneurysms is smaller than 2.66% or the rupture risk in growing aneurysms is <57.4%. The radiation-induced brain cancer risk is relatively low, and sensitivity analysis shows that the radiation-induced cancer risk does not influence the conclusions unless the risk exceeds 663-fold of the base case values. Conclusions- Given the current literature, every 5-year CTA imaging follow-up is the cost-effective strategy in patients with aneurysms ≤3 mm, resulting in better health outcomes and lower healthcare spending. Patients with aneurysms at high risk of rupture might need more aggressive management.

Neuroimaging of Pediatric Arteriopathies.

Pediatric arteriopathies are increasingly recognized in school-aged children with a variety of presenting symptoms ranging from headache, seizures, encephalopathy, and neuropsychiatric symptoms as well as focal neurologic deficits due to acute ischemic strokes. However, unlike the adult stroke population, there are differences in the clinical manifestations, the stroke mechanism, and risk factors in pediatric ischemic stroke. There has been increasing awareness and recognition of pediatric cerebral arteriopathies as a predominant stroke etiology. Prompt diagnosis of arteriopathies is essential to limit injury and prevent recurrent stroke. Based on predominant vessels involved and clinical symptoms, these arteriopathies can be broadly divided into two categories: large-medium size arteriopathies and small vessel arteriopathies. Each category can be further divided into inflammatory and noninflammatory according to their etiologies. The ability to distinguish between inflammatory and noninflammatory etiologies carries major prognostic implications for acute management and secondary stroke prevention as well as screening for systemic complications and counseling.

Pediatric Congenital Cerebrovascular Anomalies.

Congenital cerebrovascular anomalies in the pediatric age group are myriad with diverse etiologies. The purpose of this paper is to provide an imaging overview of congenital vascular malformations and vascular tumors, as these conditions are varied and the characteristic vascular abnormality may even suggest the underlying systemic condition in helping to guide further management. For example, the identification of an arterial anomaly such as agenesis/hypoplasia/duplication may warrant further evaluation for an associated syndrome. Recognition of other pertinent findings, such as persistent carotid-vertebrobasilar anastomoses for instance, would be particularly important for the planning of potential embolization/coiling of associated vascular malformation and/or aneurysm. Awareness of congenital dural sinus anomalies, including hypoplasia, aplasia, and or duplication, prevents the incorrect or overdiagnosis of sinus thrombosis. Moreover, multiple developmental venous anomalies in a patient may require further investigation for its familial association. In a similar context, there may be familial association with multiple cavernous malformations and children with central nervous system vascular malformations may have an association with other vascular conditions, eg, hereditary hemorrhagic telangiectasia, etc. An accurate description of vascular lesions is critical for understanding the natural history of the disease process and ultimately for guiding treatment. An important example of this includes Sturge-Weber syndrome, which is often incorrectly viewed as an arteriovenous malformation, but actually a type of venous malformation. Another example which is important to recognize includes the differentiation between an infantile hemangioma and a vascular malformation, particularly as the course of the pathology and the treatment is so different between the two.

Remote Cerebellar Haemorrhage: A Potential Iatrogenic Complication of Spinal Surgery.

We report the case of a 51-year-old man with no significant past medical history, who underwent elective revision spinal surgery and subsequently developed intracranial hypotension, remote cerebellar haemorrhage (RCH), and mild hydrocephalus on the fourth postoperative day. Remote cerebellar haemorrhage is a known complication of supratentorial surgery. This iatrogenic phenomenon may also occur following spinal surgery, due to dural tearing and rapid cerebral spinal fluid (CSF) leakage, resulting in intracranial hypotension and cerebellar haemorrhage. This complication may result in severe permanent neurologic sequelae; hence, it is of pertinence to diagnose and manage it rapidly in order to optimise patient outcome.

Clinical Significance of T2*gradient-recalled Echo/susceptibility-weighted Imaging Sequences in Evaluating Superficial Siderosis in the Setting of Intracerebral Tumors: Pilocytic Astrocytoma.

Superficial siderosis is the slow accumulation of hemosiderin on the pial surfaces of the brain and spinal cord. The most common cause of intracranial superficial siderosis is secondary to subarachnoid hemorrhage. Rarely, superficial siderosis can also be caused by tumors. Superficial siderosis presents clinically as hearing loss and gait instability that progressively worsen. The diagnosis is primarily made by magnetic resonance imaging; however, susceptibility-weighted imaging (SWI) and T2* gradient echo (GRE) sequences demonstrate the highest sensitivity in detecting this condition. To the best of our knowledge, there has been only one previous case of superficial siderosis secondary to a pilocytic astrocytoma of the spine. However, we present a case of intracerebral pilocytic astrocytoma resulting in superficial siderosis, with emphasis on acquisition and use of T2*GRE/SWI sequences.

Perfusion Imaging in Autoimmune Encephalitis.

Encephalitis is characterized by inflammation of brain tissue and has various infectious and noninfectious causes. CSF analysis and MRI usually reveal inflammatory changes although sometimes brain imaging may be normal. Autoimmune encephalitis is caused by antibodies against neuronal synaptic receptors, surface proteins, or intracellular proteins. In this case report, we present a 65-year-old female who presented with a fall and altered mental status. Workup for infectious etiologies was negative and MRI of the brain displayed focal restricted diffusion with corresponding T2-FLAIR hyperintensity involving gray matter structures, making the diagnosis unclear. CT perfusion of the brain demonstrated increased cerebral blood volume and cerebral blood flow in the left parietooccipital gray matter, with corresponding normal mean transit time. Following treatment failure with acyclovir, antibiotics, and steroids, the patient was found to be positive for GAD65 antibodies and diagnosed with autoimmune encephalitis. Symptoms markedly improved with plasmapheresis. Autoimmune encephalitis rarely causes restricted diffusion and this is the first case report to describe corresponding hyperperfusion on CT perfusion study.

Survival prediction based on qualitative MRI diffusion signature in patients with recurrent high grade glioma treated with bevacizumab.

BACKGROUND: Bevacizumab was approved by the FDA for the treatment of recurrent or progressive glioblastoma (GBM). Imaging responses are typically assessed by gadolinium-enhanced MRI. We sought to determine the significance of qualitative diffusion signature (manifest as variable degree of dark signal) on ADC maps in recurrent gliomas after treatment with bevacizumab. METHODS: We performed an institutional review board (IRB) approved retrospective study on patients who underwent MRI of the brain after 8 weeks of receiving bevacizumab for recurrent glioma. Patients were divided into three groups based on qualitative diffusion signature: (I) lesion not bright on diffusion weighted imaging (DWI) suggestive of no restricted diffusion (FDR0); (II) lesion bright on DWI with corresponding homogenous dark signal on apparent diffusion coefficient (ADC) maps suggestive of focal restricted diffusion likely due to bevacizumab induced necrosis (FDRn); and (III) lesion bright on DWI with corresponding homogenous faint dark signal on ADC maps suggestive of focal restricted diffusion likely due to viable tumor or heterogeneous spectrum of dark and faint dark signals on ADC maps suggestive of focal restricted diffusion likely due to viable tumor surrounding the bevacizumab induced necrosis (FDRt). RESULTS: Based on the qualitative signal on diffusion weighted sequences after bevacizumab therapy, total number of patients in group (I) were 14 (36%), in group (II) were 17 (44%); and in group (III) were 8 (20%). The median overall survival (OS) from the time of recurrence in patients belonging to group (II) was 364 days vs. 183 days for those with group (I) vs. 298 days for group (III). On simultaneous comparison of survival differences in all three groups by Kaplan-Meier analysis, group (II) was significant in predicting survival with P values for the log-rank tests <0.033. CONCLUSIONS: In patients with recurrent glioma treated with bevacizumab, the presence of homogenous dark signal (FDRn) on ADC maps at 8 weeks follow-up MRI correlated with a longer survival. Thus, use of this qualitative diffusion signature in adjunct to contrast enhanced MRI may have the widest potential impact on routine clinical care for patients with recurrent high-grade gliomas. However, prospective studies analysing its predictive value are warranted.

Dedifferentiated parosteal osteosarcoma of the calvaria.

Dedifferentiated parosteal osteosarcoma is a rare tumor and is even rarer when involving the skull bones. We present a case of a 57-year-old man with a partially ossified progressive enlarging left skull mass in the left temporoparietal region, with erosion of the outer table. Radiological diagnosis of dedifferentiated parosteal osteosarcoma was suggested, and histopathology confirmed the diagnosis.