Items tagged “refs”

2,936 results found
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Bezold abscess

A Bezold abscess is a complication of acute otomastoiditis where the infection erodes through the cortex medial to the attachment of the sternocleidomastoid muscle, at the attachment site of the posterior belly of the digastric muscle, and extends into the infratemporal fossa. It is impalpable b...
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Bifid rib

A bifid or forked or bifurcated rib is a congenital skeletal abnormality of the rib cage with the cleaved sternal end into two. They are thought to occur in ~0.2% of the population and there may be a female as well as right-sided predilection 2. Epidemiology Associations Bifid ribs can be see...
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Bilateral megalencephaly

Bilateral megalencephaly refers to megalencephaly affecting both cerebral hemispheres. Pathology Associations achondroplasia acromegaly Alexander disease Canavan disease mucopolysaccharidoses neurofibromatosis type 1 (NF1) Proteus syndrome Tay-Sachs disease tuberous sclerosis (TS) va...
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Bochdalek hernia

Bochdalek hernias , also known as pleuroperitoneal hernias, (alternative plural: herniae) are the commonest type of congenital diaphragmatic hernia. They occur posteriorly and are due to a defect in the posterior attachment of the diaphragm when there is a failure of pleuroperitoneal membrane cl...
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Bony humeral avulsion of the glenohumeral ligament lesion

Bony humeral avulsion of the glenohumeral ligament (BHAGL) lesion is just like its slightly shorter relative HAGL lesion, except as the name suggests a bony avulsion fracture is seen at humeral insertion of the inferior glenohumeral ligament. It is often associated with a subscapularis tear, an...
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Bovine arch

Bovine arch is the most common variant of the aortic arch and occurs when the brachiocephalic (innominate) artery shares a common origin with the left common carotid artery.  A bovine arch is apparent in ~15% (range 8-25%) of the population and is more common in individuals of African descent. ...
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Brain tumors in infancy

Common brain tumors in infancy (i.e. under one year of age) are quite different from those of brain tumors in adulthood. Most are located in the supratentorial region (~65%) and they carry a poor prognosis. The frequency of these tumors varies according to studies, but the most common brain tum...
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Bright rim sign (DNET)

The bright rim sign, also known as the hyperintense ring sign, has been described in dysembryoplastic neuroepithelial tumors (DNET). It is described as a well-defined rim of high signal around the DNET on FLAIR sequences. This T2/FLAIR hyperintense ring, whether complete or incomplete, is fairly...
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CREST syndrome

CREST syndrome (also known as limited systemic sclerosis or limited scleroderma) is a variant of progressive systemic sclerosis (PSS) and stands for C - calcinosis R - Raynaud phenomenon E - oesophageal dysmotility S - sclerodactyly T - telangiectasia See also systemic sclerosis
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Cataract

Cataracts are an opacification or thickening of the lens within the globe and are the leading cause of blindness in the world.  Clinical presentation Visual deterioration occurs with increasing degrees of severity, and left untreated may present as complete blindness. The diagnosis is made cli...
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Cerebrovascular malformations

Cerebrovascular malformations are vascular malformations related to the vessels that supply the brain and other cranial structures. Classification Over the years, cerebral vascular malformations have been classified in a variety of ways by many authors, often on the basis of the presence or ab...
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Cervical intraepithelial neoplasia (staging)

Cervical intraepithelial neoplasia (CIN) (also known as cervical dysplasia) is the potentailly premalignant stage in the dysplastic changes in the squamous epithelium of the cervix.  Grading of CIN is based on the degree of dysplasia seen in a sample of cervical tissue: CIN I similar to condy...
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Chemical shift artifact

Chemical shift artifact or misregistration is a type of MRI artifact. It is a common finding on some MRI sequences and used in MRS. This artifact occurs in the frequency-encoding direction and is due to spatial misregistration of fat and water molecules.  Chemical shift is due to the difference...
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Chemotherapy induced cholangitis

Chemotherapy induced cholangitis is caused when intra-arterial chemotherapy is introduced to treat liver metastases. This causes strictures of the common hepatic duct and main ducts, but spares distal and proximal (i.e. common bile duct and intrahepatic ducts).  Radiographic features similar t...
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Cholesteatoma

Cholesteatomas are histologically equivalent to an epidermoid cyst and are composed of desquamated keratinizing stratified squamous epithelium forming a mass. Clinical presentation They may be asymptomatic, or may present with conductive hearing loss, dizziness, or otorrhea. Pathology The ma...
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Chronic bilateral airspace opacification (differential)

Chronic bilateral airspace opacification is a subset of the differential diagnosis for airspace opacification. An exhaustive list of all possible causes of chronic bilateral airspace opacities is long, but a useful framework is as follows: inflammatory sarcoidosis granulomatosis with polyangi...
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Chronic unilateral airspace opacification (differential)

Chronic unilateral airspace opacification is a subset of the differential diagnoses for airspace opacification. An exhaustive list of all possible causes of chronic unilateral airspace opacities is long, but a useful framework is as follows: neoplastic post obstructive lymphoma lymphocytic ...
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Circle of Willis

The Circle of Willis is an arterial polygon (heptagon) formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk in the suprasellar cistern. This communicating pathway allows equalization of blood-flow between the two sides of...
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CSF cleft sign

The CSF cleft sign in neuroimaging can be used to distinguish an extra-axial lesion from an intra-axial lesion and is typically used in the description of a meningioma. Classically, the cleft was regarded as representing a thin rim of CSF between a tumor and brain parenchyma. However, it often ...
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Clinically isolated syndrome

Clinically isolated syndrome (CIS) is the first episode suggestive of demyelination 1,2. It can either be monofocal (single lesion) or multifocal 1,2. Not all patients with CIS will go on to develop multiple sclerosis however if at presentation there are changes on MRI suggestive of MS, then the...