Causes of Intracranial Hypotension: Spontaneous, Traumatic, and Iatrogenic Cerebrospinal Fluid Leaks
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.
Intrathecal Contrast-enhanced Computed Tomography and MR Cisternography for Skull Base Cerebrospinal Fluid Leaks and Other Intracranial Applications
Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. The initial assessment of rhinorrhea or otorrhea, which may be suspected owing to an acquired skull base CSF leak, requires integration of clinical assessment and biochemical confirmation of CSF. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to intrathecal contrast-enhanced cisternography may be necessary. We also review various other applications for diagnosis of intracranial abnormalities using contrast-enhanced cisternography.
Image-guided Epidural Blood Patching and Fibrin Glue Occlusion of Cerebrospinal Fluid Leaks and Venous Fistulas
There have been major advances in the diagnosis and treatment of spontaneous intracranial hypotension (SIH). While once thought to be a rare condition, the occurrence is not uncommon if diagnosed adequately. Our greater understanding of SIH is based on three main points: (1) awareness of the various types of spontaneous spinal cerebrospinal fluid (CSF) leaks; (2) advanced myelography with the precision to detect dural tears and CSF-venous fistulas; and (3) updated treatment techniques of epidural patching, embolization, and surgery. This review discusses the various types of epidural patching for CSF leaks.
The Subarachnoid Space: Percutaneous Access for Diagnosis and Image-Guided Therapies
Image-guided Access to the Spinal Subarachnoid Space in Children
Image guidance is becoming standard of practice for cerebrospinal fluid sampling in children to improve success rates and avoid complications. This article discusses various imaging guidance techniques available in the pediatric age group. For neonates and infants, imaging guidance using ultrasound is the technique of choice, and for older children, fluoroscopy or even cone beam computed tomography can be used when anatomy is complex.
Standard Fluoroscopic and Computed Tomography-Guided Lumbar Punctures
Image-guided lumbar puncture (LP) remains an important part of the modern practice of neuroradiology. This review outlines the relevant anatomy, safety considerations, and techniques in performing fluoroscopic and computed tomography-guided LPs.
Alternative Percutaneous Dural Puncture Routes: Cervical, Thoracic, Lumbar, and Sacral
Patients requiring lumbar punctures (LPs) are frequently challenging or may be impossible to do through a standard lower lumbar route. Therefore, if clinically indicated, consideration of alternative anatomic access routes to the spinal subarachnoid space may be necessary. However, some of these approaches are unpopular or seldom used, may be challenging to perform, or are associated with potential significant complications especially when combined with limited operator experience. Here we review the techniques and drawbacks of multiple different approaches for percutaneous insertion of spinal needles into the spinal dural sac as alternatives to standard interlaminar low LPs.
Cerebrospinal Fluid Pressure Measurement and Infusion Studies Using Lumbar Puncture
Lumbar puncture provides an easy way of accessing the subarachnoid space. Measuring of the opening cerebrospinal fluid pressure is the most commonly used method of evaluating intracranial pressure but provides basic snapshot information only. Further insights into cerebrospinal fluid dynamics can be obtained through infusion studies, which rely on measurement of the degree of pressure change in response to addition of fluid volume into the subarachnoid space. The authors describe applications of these 2 techniques pertinent to a practicing neuroradiologist, who may be asked to assist with fluoroscopy-guided lumbar puncture in patients with increased body mass index or difficult spine anatomy.
Dural Puncture Complications
Dural puncture, commonly referred to as lumbar puncture (LP), carries the risk of rare but serious complications including post-dural puncture headache, hemorrhage, herniation, and infection. These complications can lead to suboptimal patient outcomes including significant morbidity and mortality in some instances. This review comprehensively examines potential LP complications, including their incidence, pathophysiology, risk factors, clinical presentations, imaging findings, preventative measures, and treatment strategies. Familiarity with these complications will equip clinicians to effectively manage these complications through prompt recognition, timely diagnosis, and implementation of appropriate preventative measures.
Lumbar Transforaminal Injections of Nusinersen in Spinal Muscular Atrophy Patients
Following a review of spinal muscular atrophy pathogenesis and current therapeutics, a comprehensive review of transforaminal lumbar injections is provided. Patient preparation, special considerations, procedural technique, complications, and alternative approaches are discussed.
Fluoroscopic, Computed Tomographic, and Magnetic Resonance Myelography
Despite all the advantages of magnetic resonance (MR) imaging, there still exist contraindications or limitations to its use. Thus, MR imaging has not entirely replaced fluoroscopic or computed tomographic (CT) myelography to depict the outline of the spinal cord and its nerve roots after intrathecal injection of contrast medium. The growing recent interest of neuroradiologists to accurately diagnose and treat cerebrospinal fluid leaks has also driven a resurgent need for familiarity with this image-guided procedure. This article reviews the numerous technical and periprocedural aspects of fluoroscopic and CT myelography, and the use of noninvasive MR myelography in certain clinical scenarios.
Imaging Anatomy of the Cerebrospinal Fluid Spaces
The cerebrospinal fluid spaces of the spine and brain are an intricate network of tissues with complex anatomic relationships. Understanding the normal imaging anatomy and variants of these spaces is crucial for accessing the spinal subarachnoid space and evaluating patients with suspected CSF leaks. This article reviews the imaging anatomy of the cerebrospinal fluid spaces in the spine and brain with emphasis on clinically relevant anatomy for percutaneous needle access to the spinal subarachnoid space and management of patients with CSF leak.
Myelographic Techniques for the Localization of Cerebrospinal Fluid 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.
Image-Guided Percutaneous Access of the Subarachnoid Space Comes of Age
Arterial Ischemic Stroke in Children
Arterial ischemic stroke (AIS) in children has a high mortality and life-long disability rate in surviving patients. Diagnostic delays are longer and risk factors are different compared with AIS in the adult population. Congenital heart disease, cervical arterial dissection, and intracranial arteriopathies are the main causes of AIS in children. New revascularization time windows in children require the definition of diagnostic protocols for stroke in each referral center. In this article, we discuss the neuroimaging techniques and protocols, describe the main underlying causes, and review the current treatment options for pediatric and perinatal AIS.
Intracranial Arterial Aneurysms in Childhood
Intracranial arterial aneurysms in children are rare. They differ from adult aneurysms in their etiology, natural history, and management approach. Unruptured asymptomatic aneurysms in children can often be observed for growth over time. Endovascular treatment has become the primary interventional modality in children with intracranial aneurysms. The authors discuss the management approach to pediatric intracranial aneurysms.
Steno-occlusive Intracranial Large Vessel Arteriopathies in Childhood: A Pattern Oriented Approach to Neuroimaging Diagnosis
Intracranial steno-occlusive large vessel arteriopathies refer to abnormalities of the arterial wall that typically express luminal stenosis. Notably, some entities that can find themselves within this category may also express luminal dilation, and/or aneurysm formation as an alternative phenotype. Intracranial steno-occlusive large vessel arteriopathies are a leading cause of arterial ischemic stroke (AIS) in children, often progress, and can predispose to recurrent brain infarction. Intracranial arterial dissections account for a subset of cases expressing the focal cerebral arteriopathy (FCA) phenotype because the affected arterial segment, clinical presentation, and AIS patterns are very similar to the inflammatory subtype of FCA.
Imaging of Hemorrhagic Stroke in Children
Hemorrhagic stroke (HS) is an important cause of neurologic morbidity and mortality in children and is more common than ischemic stroke between the ages of 1 and 14 years, a notable contradistinction relative to adult stroke epidemiology. Rapid neuroimaging is of the utmost importance in making the diagnosis of HS, identifying a likely etiology, and directing acute care. Computed tomography and MR imaging with flow-sensitive MR imaging and other noninvasive vascular imaging studies play a primary role in the initial diagnostic evaluation. Catheter-directed digital subtraction angiography is critical for definitive diagnosis and treatment planning.
Pediatric Spinal Vascular Abnormalities: Overview, Diagnosis, and Management
Hemangioblastomas are true benign vascular neoplasms arising from pluripotent mesenchymal stem cells that give rise to vascular endothelial cells and are most commonly found in the cerebellum, spinal cord, brainstem, and retina. These tumors may be isolated sporadic lesions or may be associated with hereditary genetic factors in the case of von Hippel-Lindau (VHL) syndrome. Spinal cord haemangioblastomas constitute 1.1% to 2.4% of all central nervous system tumors105, with the majority being single tumors that present in the fourth decade of life 106. In the pediatric population, sporadic spinal cord hemangioblastomas are exceedingly rare. The prevalence of spinal cord hemangioblastomas in children is increased among those with VHL syndrome. The thoracic cord is the most common site for spinal cord hemangioblastomas, followed by the cervical cord. Although these tumors are benign, they cause disabling symptoms due to spinal cord compression, syringomyelia, or hemorrhage from the tumor itself or from aneurysms that form on tumor-feeding arteries or intra-tumoral vessels.