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IgG4-Related Disease in the Head and Neck

Introduction Background IgG4-related disease (IgG4-RD) is a relatively recently recognized fibroinflammatory condition of unknown etiology characterized by elevated serum IgG4, plasmacytic infiltration, multifocal tumefactive fibrosis, and clinical improvement by steroid therapy. The association between autoimmune (sclerosing) pancreatitis and elevated serum IgG4 was first described by Hamano et al. in 2001, but it wasn't until 2003 that the systemic nature of IgG4-RD was discovered. After the pancreas, the…

Thyroid-Associated Orbitopathy

Introduction Thyroid-associated orbitopathy (TAO), thyroid eye disease (TED), dysthyroid/TAO, and Graves orbitopathy all refer to a poorly understood autoimmune phenomenon resulting in the adipogenesis of orbital fat. An estimated 40% of patients with Graves disease develop TAO. Up to 20% of patients presenting with thyroid orbitopathy are concurrently diagnosed with Graves disease. Affected populations naturally parallel that of Graves disease, and TAO occurs most commonly in…

Recurrent Suppurative Thyroiditis Due to Piriform Sinus Fistula

Introduction Anomalies arising from the third and fourth branchial cleft remnants are quite rare. In particular, branchial abnormalities related to the pharynx are only a small subset of the already rare collection of branchial cleft lesions. Branchial abnormalities with a sinus tract connecting to the pharynx usually present with acute suppurative thyroiditis and a thyroid abscess. The sinus tract connecting to the pharynx serves as a…

Orbital Infection

Introduction There are various forms of orbital infection, including those listed in the Jain-Rubin classification: 1. Periorbital cellulitis 2. Orbital cellulitis with or without intracranial complications 3. Orbital abscess with or without intracranial complications a. Intraorbital abscess, which may arise from collection of purulent material in an orbital cellulitis b. Subperiosteal abscess, which may lead to true infection of orbital soft tissues In addition, orbital infections…

Dorsal Thoracic Arachnoid Abnormalities

Introduction Deformities along the dorsal aspect of the thoracic spinal cord are occasionally identified on magnetic resonance imaging (MRI), often in patients presenting with myelopathy ( Fig. 36.1 ). A variety of nontumoral etiologies result in deformities of the dorsal thoracic cord, of which many are related to abnormalities of the dorsal arachnoid. These abnormalities include intradural arachnoid cyst as well as dorsal thoracic arachnoid webs,…

Hirayama Disease

Introduction Hirayama disease is a rare, slowly progressive, and self-limiting cervical myelopathy related to neck flexion in young adults. It is characterized by a pure focal amyotrophy in the C7-T1 innervated musculature. It presents classically in an adolescent male with progressive asymmetric upper extremity muscular weakness and atrophy. During neck flexion, forward displacement of the posterior dural sac is thought to result in minimal but additive…

Spinal Cord Astrocytoma

Introduction Spinal cord astrocytomas are quite uncommon and account for only 3% to 4% of all central nervous system (CNS) astrocytomas. Furthermore, although intracranial glioblastomas are the most common primary brain parenchymal neoplasm, spinal cord glioblastomas are exceedingly rare. The characteristic asymmetric location of small spinal cord astrocytomas is due to the location of their peripherally located astrocytic cells of origin, as well as their affinity…

Spinal Cord Ependymoma

Introduction Spinal cord ependymomas are the most common intramedullary tumor in adults and the second most common tumor in children after astrocytomas. Ependymomas typically present within the fourth decade of life and affect men more often than women. A higher incidence of these tumors occurs in patients with neurofibromatosis type II. The presenting symptoms are often insidious and nonspecific, with the majority of patients being symptomatic…

Subacute Progressive Ascending Myelopathy

Introduction Subacute progressive ascending myelopathy (SPAM) is an exceedingly rare and poorly understood complication of spinal cord injury. As the natural history of this process is quite peculiar, it is especially important for the imaging interpreter to be aware of this entity. Following a latent period a few weeks after spinal cord injury, patients usually present with an abrupt ascending neurologic deficit. The sudden onset of…

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…