Role of Advanced MR Imaging in Diagnosis of Neurological Malignancies: Current Status and Future Perspective.

Lesions of the central nervous system (CNS) can present with numerous and overlapping radiographical and clinical features that make diagnosis difficult based exclusively on history, physical examination, and traditional imaging modalities. Given that there are significant differences in optimal treatment protocols for these various CNS lesions, rapid and non-invasive diagnosis could lead to improved patient care. Recently, various advanced magnetic resonance imaging (MRI) techniques showed promising methods to differentiate between various tumors and lesions that conventional MRI cannot define by comparing their physiologic characteristics, such as vascularity, permeability, oxygenation, and metabolism. These advanced MRI techniques include dynamic susceptibility contrast MRI (DSC), diffusion-weighted imaging (DWI), dynamic contrast-enhanced (DCE) MRI, Golden-Angle Radial Sparse Parallel imaging (GRASP), Blood oxygen level-dependent functional MRI (BOLD fMRI), and arterial spin labeling (ASL) MRI. In this article, a narrative review is used to discuss the current trends in advanced MRI techniques and potential future applications in identifying difficult-to-distinguish CNS lesions. Advanced MRI techniques were found to be promising non-invasive modalities to differentiate between paraganglioma, schwannoma, and meningioma. They are also considered promising methods to differentiate gliomas from lymphoma, post-radiation changes, pseudoprogression, demyelination, and metastasis. Advanced MRI techniques allow clinicians to take advantage of intrinsic biological differences in CNS lesions to better identify the etiology of these lesions, potentially leading to more effective patient care and a decrease in unnecessary invasive procedures. More clinical studies with larger sample sizes should be encouraged to assess the significance of each advanced MRI technique and the specificity and sensitivity of each radiologic parameter.

Resection of a large thoracolumbar intradural ependymoma: a 2D operative video.

In this video, the authors present the resection of a large thoracolumbar intradural ependymoma in a 33-year-old female. The patient underwent T9-L3 laminectomies, intradural tumor resection, and posterior instrumented fixation and fusion. The surgical procedure aimed to relieve the mass effect, obtain a diagnosis, prevent further neurological decline, and achieve a potential curative resection. The pathology confirmed a myxopapillary ependymoma, a rare tumor with a preference for the conus medullaris, cauda equina, or filum terminale. The video provides insights into the case, surgical steps, clinical outcomes, and background information on myxopapillary ependymomas and treatment options.

Clival intraosseous myxoma treated with an endoscopic endonasal approach: illustrative case.

BACKGROUND: Solitary lesions of the clivus, especially nonchordomatous ones, are exceptionally rare pathologies representing only 0.1%-0.2% of intracranial tumors that may present diagnostic and therapeutic challenges. Intraosseous myxomas are benign tumors arising from mesenchymal cells with an unknown pathophysiology. OBSERVATIONS: In this article, a 15-year-old male with clival intraosseous myxoma who was treated via an endoscopic endonasal surgical approach is presented. The patient became symptomatic after a baseball struck his head, leading to throbbing headaches and visual difficulties for tracking objects. Examination noted diplopia, cranial nerve VI palsy, and ptosis. After imaging revealed a tumor extending to the left cavernous sinus with bulging of the dorsal clivus against the basilar artery/ventral pons, resection was performed. Postoperatively, the patient noted ocular motility and alignment improvement without further complications. LESSONS: Clival masses present with symptoms from compromised neurovascular structures including visual disturbances and trigeminal sensory deficits. Given the rarity of these entities, patients may postpone further treatment until workup; this patient was misdiagnosed for possible concussion until several weeks passed. A PubMed database review of cranial myxoma cases was conducted to identify solitary clival intraosseous myxoma cases. This case is one of the few in which this pathology was treated through an endoscopic endonasal operative approach without complications, demonstrating its safety and effectiveness.

Lead toxicity due to retained intracranial bullet fragments: illustrative case.

BACKGROUND: Lead toxicity (plumbism) secondary to retained lead bullet fragments is a rare complication in patients with gunshot wounds. To the authors' knowledge, there has been no definitive case reported of lead toxicity due to retained intracranial bullet fragments. OBSERVATIONS: The authors reported the case of a 23-year-old man who presented after being found down. Computed tomography scanning of the head revealed bullet fragments within the calvaria adjacent to the left transverse sinus. During follow-up, he developed symptoms of plumbism with paresthesias in his bilateral hands and thighs, abdominal cramping, labile mood, and intermittent psychosis. Plumbism was confirmed with sequentially elevated blood lead levels (BLLs). The patient opted for surgical removal of the bullet fragments, which led to reduction in BLLs and resolution of his symptoms. LESSONS: Although rare, lead toxicity from retained intracranial bullet fragments should be considered in patients who have suffered a gunshot wound to the head and have symptoms of lead toxicity with elevated BLLs. For safe and accessible intracranial bullet fragments in patients with plumbism, surgical intervention may be indicated.

COVID-19 Testing in the Era of Modern Neurosurgery: Mitigating Risk in Our Vulnerable Patient Populations.

BACKGROUND: The respiratory illness identified as coronavirus disease 2019 (COVID-19) has resulted in a pandemic illness that has changed the face of healthcare. As the COVID-19 pandemic continues, patients have continued to require neurosurgical interventions, and the endoscopic endonasal approach for surgery has continued to be a mainstay treatment of pituitary tumors and anterior skull base lesions. METHODS: We sought to highlight the current lack of recommendations regarding testing protocols for neurosurgical patients. RESULTS: We implemented a novel testing protocol for our patient populations at increased risk and have proposed a model that can be used at other institutions to mitigate the risk of complications associated with some forms of COVID-19 testing. CONCLUSION: Patients with anterior skull base defects may be at risk with current COVID-19 testing protocols, and may benefit from alternative specimen collection strategies.

Understanding Variable Motor Responses to Direct Electrical Stimulation of the Human Motor Cortex During Brain Surgery.

Direct electrical stimulation of the brain is the gold standard technique used to define functional-anatomical relationships during neurosurgical procedures. Areas that respond to stimulation are considered "critical nodes" of circuits that must remain intact for the subject to maintain the ability to perform certain functions, like moving and speaking. Despite its routine use, the neurophysiology underlying downstream motor responses to electrical stimulation of the brain, such as muscle contraction or movement arrest, is poorly understood. Furthermore, varying and sometimes counterintuitive responses can be seen depending on how and where the stimulation is applied, even within the human primary motor cortex. Therefore, here we review relevant neuroanatomy of the human motor system, provide a brief historical perspective on electrical brain stimulation, explore mechanistic variations in stimulation applications, examine neurophysiological properties of different parts of the motor system, and suggest areas of future research that can promote a better understanding of the interaction between electrical stimulation of the brain and its function.