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.

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.

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.

The preliminary radiogenomics association between MR perfusion imaging parameters and genomic biomarkers, and their predictive performance of overall survival in patients with glioblastoma.

The radiogenomics association of neovascularization is important for overall survival (OS) in glioblastoma patients and remains unclear. The purpose of this study is to assess the association between MR perfusion imaging derived parameters and genomic biomarkers of glioblastoma, and to evaluate their prognostic value. This retrospective study enrolled 41 patients with newly diagnosed glioblastoma. The mean and maximal relative cerebral blood volume (rCBV) ratio (rCBVmean and rCBVmax), derived from MR perfusion weighted imaging, of the enhancing tumor, as well as maximal rCBV ratio of peri-enhancing tumor area (rCBVperi-tumor) were measured. The ki-67 labeling index, mammalian target of rapamycin (mTOR) activation, epidermal growth factor receptor (EGFR) amplification, isocitrate dehydrogenase (IDH) mutation and TP53 were assessed. There was a significant correlation between rCBVmax and mTOR based on Pearson's correlations with Benjamini-Hochberg adjustment for controlling false discovery rate, p = 0.047. The rCBVperi-tumor showed significant correlation with mTOR (p = 0.0183) after adjustment of gender and EGFR status. The mean rCBVperi-tumor value of the patients with OS shorter than 14 months was significantly higher than patients with OS longer than 14 months, p = 0.002. The rCBVperi-tumor and age were the two strongest predictors of OS (hazard ratio = 1.29 and 1.063 respectively) by Cox regression analysis. This study showed that hemodynamic abnormalities of glioblastoma were associated with genomics activation status of mTOR-EGFR pathway, however, the radiogenomics associations are different in enhancing and peri-enhancing area of glioblastoma. The rCBVperi-tumor has better prognostic value than genomic biomarkers alone.

Toxins in Brain! Magnetic Resonance (MR) Imaging of Toxic Leukoencephalopathy - A Pictorial Essay.

Toxic leukoencephalopathy results from damage to the white matter caused by various toxins. It manifests itself as white matter signal abnormalities with or without the presence of restricted diffusion. These changes are often reversible if the insulting agent is removed early, with the exception of posthypoxic leukoencephalopathy that can manifest itself 1-2 weeks after the initial insult. However, many other potential causes of white matter signal abnormalities can mimic the changes of toxic leukoencephalopathy. Thus, familiarity with the causes, clinical presentation and particularly imaging findings of toxic leukoencephalopathy is critical for early treatment and improved prognosis. The purpose of this pictorial essay is to familiarize the reader with the various causes of toxic leukoencephalopathy along with its differential diagnoses and mimics.

Cerebral convexity subarachnoid hemorrhage: various causes and role of diagnostic imaging.

Computed tomography (CT) and magnetic resonance imaging (MRI) have made it relatively easy to diagnose cortical convexity subarachnoid hemorrhages (cSAH); however, the evaluation of these hemorrhages should not be limited to size and location. It is imperative that possible underlying etiologies be identified so that clinicians may properly treat and prevent this potentially catastrophic event. The goal of this article is to review etiologies of cortical convexity subarachnoid hemorrhages, from common causes such as cerebral amyloid angiopathy to less common causes such as reversible cerebral vasoconstriction syndrome and moyamoya. The specific imaging findings of each etiology that may be responsible for these hemorrhages are described in this article so that the radiologist may properly aid in the diagnosis of the underlying cause.

Correlation between progression free survival and dynamic susceptibility contrast MRI perfusion in WHO grade III glioma subtypes.

The purpose of this study was to determine whether dynamic susceptibility contrast MR perfusion relative cerebral blood volume (rCBV) correlates with prognosis of World Health Organization (WHO) grade III glial tumors and their different subtypes. Retrospective evaluation of pre-treatment tumor rCBV derived from dynamic susceptibility contrast MR perfusion was performed in 34 patients with histopathologically diagnosed WHO grade III glial tumors (anaplastic astrocytomas (n = 20), oligodendrogliomas (n = 4), and oligoastrocytomas (n = 10)). Progression free survival was correlated with rCBV using Spearman rank analysis. ROC curve analysis was performed to determine the operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time. For all grade III tumors (n = 34) the mean rCBV was 2.51 with a progression free survival of 705.5 days. The mean rCBV of anaplastic astrocytomas was 2.47 with progression free survival 495.2 days. In contrast, the mean rCBV for oligodendroglial tumors was 2.56 with a progression free survival of 1005.6 days. Although there was no significant correlation between rCBV and progression free survival among all types of grade III gliomas (P = 0.12), among anaplastic astrocytomas there was a significant correlation between pretreatment rCBV and progression free survival with correlation coefficient of -0.51 (P = 0.02). The operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time (446.5 days) was 2.86 with 78 % accuracy and there was a significant difference between the survival of patients with anaplastic astrocytomas in the dichotomized groups (P = 0.0009). Pre-treatment rCBV may serve as a prognostic imaging biomarker for anaplastic astrocytomas, but not grade III oligodendroglioma tumors.

CT perfusion in acute stroke: know the mimics, potential pitfalls, artifacts, and technical errors.

The CT perfusion (CTP) imaging of brain has been established as a clinically useful tool in multimodality imaging of acute stroke. All abnormalities seen on perfusion CT are not specifically related to acute infarct. There are many neurologic diseases causing symptoms simulating cerebrovascular disease produce an alteration of brain perfusion and thus can result in perfusion CT abnormalities. There are many pitfalls and artifacts in acquiring the data, calculation of maps and choosing arterial input function. We analyze and classify all these aspects, to allow the technician and the radiologist to know exactly what to avoid and what to choose, and we indicate the way to improve the quality of examination. The knowledge of mimics and pitfalls in acute stroke imaging can be helpful in accurate interpretation of these examinations.

Choroid Plexitis and Obstructive Hydrocephalus Secondary to Cryptococcal Meningoencephalitis in an Immunocompetent Individual With Remarkable Imaging Findings: A Case Report.

Cryptococcus is an invasive and opportunistic fungus usually associated with immunocompromised individuals. Invasion of the choroid plexus by Cryptococcus is rare. This report presents the radiologic findings of a previously healthy male with bilateral choroid plexus invasion complicated by obstructive hydrocephalus.

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.

Diffusion-weighted imaging for differentiating benign from malignant skull lesions and correlation with cell density.

OBJECTIVE: The objective of our study was to determine the utility of diffusion-weighted imaging (DWI) and cell density for differentiating benign from malignant skull lesions. MATERIALS AND METHODS: A retrospective review was performed. Minimum apparent diffusion coefficient (ADC) values were measured and normalized to white matter, which we refer to as "normalized ADC," in 24 skull lesions (12 malignant and 12 benign) in 18 patients. In addition, cell densities were measured in 15 cases and correlated with ADC values. RESULTS: The average minimum ADC in malignant tumors was 0.70 × 10(-3) mm(2)/s versus 1.11 × 10(-3) mm(2)/s in benign tumors (p = 0.0037). Similarly, the average normalized ADC for malignant tumors was 1.03, whereas the average normalized ADC for benign tumors was 1.65 (p = 0.0012). Receiver operating characteristic curve analysis yielded optimal normalized ADC and ADC thresholds of 1.23 (accuracy, 84.6%; sensitivity, 75.0%; specificity, 92.3%) and 1.01 × 10(-3) mm(2)/s (accuracy, 83.7%; sensitivity, 83.3%; specificity, 84.6%), respectively. There was a significant inverse correlation between cell density and normalized ADC (r = -0.58; p = 0.023). The low cellularity in chordoma and low-grade chondrosarcoma and high cellularity in eosinophilic granuloma may explain the DWI features of these lesions. CONCLUSION: ADC values in skull lesions correlate with cell density and can potentially narrow the differential diagnoses for indeterminate skull lesions. Understanding the histopathologic features of skull lesions can refine interpretation of DWI.

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.

Border zone infarcts: pathophysiologic and imaging characteristics.

Border zone or watershed infarcts are ischemic lesions that occur in characteristic locations at the junction between two main arterial territories. These lesions constitute approximately 10% of all brain infarcts and are well described in the literature. Their pathophysiology has not yet been fully elucidated, but a commonly accepted hypothesis holds that decreased perfusion in the distal regions of the vascular territories leaves them vulnerable to infarction. Two types of border zone infarcts are recognized: external (cortical) and internal (subcortical). To select the most appropriate methods for managing these infarcts, it is important to understand the underlying causal mechanisms. Internal border zone infarcts are caused mainly by hemodynamic compromise, whereas external border zone infarcts are believed to result from embolism but not always with associated hypoperfusion. Various imaging modalities have been used to determine the presence and extent of hemodynamic compromise or misery perfusion in association with border zone infarcts, and some findings (eg, multiple small internal infarcts) have proved to be independent predictors of subsequent ischemic stroke. A combination of several advanced techniques (eg, diffusion and perfusion magnetic resonance imaging and computed tomography, positron emission tomography, transcranial Doppler ultrasonography) can be useful for identifying the pathophysiologic process, making an early clinical diagnosis, guiding management, and predicting the outcome.

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.

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.

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.