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Spinal Cord Infarction

Introduction The diagnosis of spinal cord infarction (SCI) has changed significantly in the past decade, largely due to the contributions of neuroimaging. Historically SCI was considered to be rare, with the definitive diagnosis requiring postmortem examination and probable diagnosis requiring the appropriate clinical context (usually aortic dissection or surgery) and exclusion of other possibilities. With the advent of spinal cord diffusion-weighted imaging (DWI), however, improved diagnosis…

Syringohydromyelia

Introduction The term syringomyelia was introduced by the French pathologist and clinician Charles-Prosper Ollivier d'Angers in 1827 to described cystic cavities in the spinal cord. More specifically, hydromyelia refers to dilatation of the central canal lined by ependymal cells and syringomyelia refers to a cystic cord cavity separate from the central canal not lined by ependymal cells. This distinction has little practical importance as both entities…

Vertebral Hemangioma

Introduction Vertebral hemangiomas (VHs) are benign vascular tumors frequently encountered as incidental findings on computed tomography (CT) or magnetic resonance imaging (MRI). The vast majority are quiescent, with classic imaging features that are reassuring to radiologists and patients, and are called typical hemangiomas. VHs that are clinically quiescent but do not demonstrate classic imaging features are frequently referred to as atypical hemangiomas. These may produce a…

Chordoma

Introduction Chordomas are unusual tumors with seemingly unconventional traits. Most notably, they are malignant primary bone tumors but not sarcomas. They derive from embryologic cell remnants but predominantly affect late-middle-age adults, and they behave aggressively but grow slowly. Chordomas present with long-standing symptoms related to local mass effect or invasion. At the skull base, they often cause headaches and cranial neuropathies. In the spine, they incite…

Tuberculous Spinal Infection

Introduction Tuberculosis (TB) is classically considered an infectious disease of developing countries; however, it has made a resurgence in other areas of the world with the increased use of immunosuppressive drugs, increased immigration, and the relatively recent appearance of HIV. The musculoskeletal system is the most common extrapulmonary site of TB infection, with spinal involvement seen in 50% of skeletal cases. Tuberculous spondylitis refers to vertebral…

Discitis-Osteomyelitis

Introduction Infections of the spine are not uncommon in clinical practice. There are many terms used to describe essentially the same pathologic entity at different stages of evolution. In adults, pyogenic infections typically spread hematogenously to the vertebral endplate (vertebral osteomyelitis), continue through the intervertebral disc to involve the adjacent vertebral body (discitis-osteomyelitis), and may develop abscesses in paraspinal and epidural spaces (psoas or epidural abscesses)…

Kummel Disease

Introduction Kummel disease was first described by Hermann Kummell in 1891 as delayed posttraumatic vertebral collapse occurring weeks or months after an often minimal injury. The mechanism is still debated. These lesions are most widely believed to be secondary to delayed osteonecrosis of the vertebral body, potentially related to vascular disruption of the anterior watershed territory of the vertebral body following trauma. It is a rarely…

Lumbar Interbody Fusion

Introduction The ultimate goal of lumbar interbody fusion procedures is to relieve debilitating pain or prevent neurologic compromise. Fusion is achieved via the promotion of solid ossification across a lumbar disk space, known as solid arthrodesis ( Fig. 24.1 ). Interbody fusion (in other words, fusion across the disk space) can be performed by various surgical approaches. The aim is to restore and maintain disk space…

Ossification of the Posterior Longitudinal Ligament

Introduction Ossification of the posterior longitudinal ligament (OPLL) is a slowly progressive disorder that can result in spinal stenosis and myelopathy. Myelopathy in patients with OPLL is related to both static and dynamic factors. The most common anatomic location is the cervical spine, although the process may also involve the thoracic and lumbar regions. The prevalence of OPLL increases with age and is most common in…

Hypertrophic Olivary Degeneration

Introduction Hypertrophic olivary degeneration (HOD) is the result of an insult to the dentato-rubro-olivary pathway ( Fig. 22.1 ), otherwise known as the Guillain-Mollaret triangle (GMT). After an insult (infarct, hemorrhage, trauma, tumor, surgery) that disrupts the GMT, hypertrophic degeneration of the affected inferior olivary nucleus (ION) develops. The counterintuitive degenerative hypertrophy (rather than atrophy) of the ION can lead to confusion. Of note, lesions involving…

Pituitary Apoplexy

Introduction Pituitary apoplexy (PA) is a rare clinical condition presenting most commonly with acute headache as well as vomiting, visual impairment, ophthalmoplegia, altered mental state, and potentially panhypopituitarism. Occasionally it may be fatal. The syndrome is caused by hemorrhage into and/or infarction of the pituitary gland. PA is most commonly caused by hemorrhage into a preexisting macroadenoma. Asymptomatic pituitary hemorrhage without clinically defined apoplexy syndrome can…

Rathke Cleft Cyst

Introduction Rathke cleft cysts are cystic sellar and suprasellar lesions arising from remnants of the embryonic Rathke pouch, a structure of ectodermal origin that folds superiorly from the pharynx during the fourth week of gestation. In the sella, Rathke pouch gives rise to the adenohypophysis anteriorly and intermediate lobe of the pituitary gland posteriorly. In the suprasellar cistern, Rathke pouch gives rise to the pars tuberalis.…

Partially Empty Sella

Introduction The empty sella turcica was first described in 1949 as a condition where the sella turcica is only partially filled by the pituitary gland, which appears flattened against the sellar floor ( Fig. 19.1 ). Autopsy studies confirm the high disease prevalence reported to be 5.5% to 20% of the general population. Not surprisingly, many patients who undergo brain imaging will have a partially empty…

Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

Introduction Idiopathic intracranial hypertension (IIH) is a disorder of elevated intracranial pressure (ICP) without apparent inciting etiology. Pseudotumor cerebri (PTC) is also a commonly accepted term describing the same disorder. Many authors advocate limiting the definition of IIH to a truly idiopathic subset of PTC, as PTC encompasses a list of known nontumor conditions resulting in elevated ICP, including the following: cerebrospinal fluid (CSF) malabsorption, superior…

Intracranial Hypotension

Introduction Intracranial hypotension is a clinical manifestation of low cerebrospinal fluid (CSF) volume or pressure caused by a dural CSF leak. It is usually precipitated by dural injury from an iatrogenic event such as a lumbar puncture, recent surgery, overshunting, or trauma. Spontaneous intracranial hypotension (SIH) was first described by Georg Schaltenbrand in 1938 and has been recognized as a rare but significantly underdiagnosed differential consideration…

Hemangioblastoma

Background Hemangioblastoma is a vascular tumor of the central nervous system (CNS). It most commonly occurs within or on the surface of the cerebellum and represents the most common primary tumor of the posterior fossa in adults. Hemangioblastomas may also occur within the spine. Single tumors may be sporadic, but multiple tumors are almost always associated with von Hippel-Lindau (VHL) disease. Sporadic tumors appear in the…

Treated Gliomas

Introduction Due to the wide array of available accepted therapies, as well as the increasing number of experimental treatments undergoing clinical trials for the management of glial neoplasms, the task of the radiologist to make appropriate interpretations can seem daunting. In this chapter, we review the clinical, pathologic, and imaging findings associated with these therapies and offer recommendations on the imaging approach in these scenarios. Surgical…

Neurosarcoidosis

Introduction Sarcoidosis is a chronic idiopathic, noninfectious, granulomatous disease characterized by the formation of noncaseating granulomas. It most commonly involves the lungs, skin, and lymph nodes, although any organ or organ system may be affected. The disease most commonly affects African Americans and persons of Scandinavian descent and has a slight female predilection. There is a bimodal age distribution with the initial peak in the third…

Central Nervous System–Immune Reconstitution Inflammatory Syndrome

Introduction Central nervous system–immune reconstitution inflammatory syndrome (CNS-IRIS) represents a diverse group of disorders, all of which are characterized by an exaggerated inflammatory response to either a dead or dying opportunistic infection, viable pathogen from a persistent infection, or a self-antigen. First described in 1992 and most commonly seen in patients with HIV immunosuppression, CNS-IRIS has also been reported in patients following discontinuation of corticosteroids, anti-TNF-α…

Progressive Multifocal Leukoencephalopathy

Introduction Progressive multifocal leukoencephalopathy (PML) is an opportunistic subacute demyelinating infection of the central nervous system (CNS) first described in 1958. The causative agent is the polyomavirus JC that has tropism for oligodendrocytes. Asymptomatic primary infection occurs in childhood, with the virus remaining latent in the kidneys and lymphoid tissue. With profound cellular immunosuppression, the virus reactivates and spreads to the CNS. Presenting symptoms from most…