Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
More than 200 results
Article
Second branchial cleft cyst
Second branchial cleft cysts are a cystic dilatation of the remnant of the second branchial cleft (see branchial apparatus), and along with second branchial fistulae and sinuses accounts for 95% of all branchial cleft anomalies.
Clinical presentation
Although a congenital abnormality, they ten...
Article
Aberrant internal carotid artery
Aberrant internal carotid artery is a variant of the internal carotid artery and represents a collateral pathway resulting from involution of the normal cervical portion (first embryonic segment) of the internal carotid artery 5.
Gross anatomy
There is consequent enlargement of the usually sma...
Article
Achondroplasia
Achondroplasia is a congenital genetic disorder resulting in rhizomelic dwarfism and is the most common skeletal dysplasia. It has numerous distinctive radiographic features.
Epidemiology
It occurs due to sporadic mutations in the majority of cases but can be inherited as an autosomal dominan...
Article
Vestibular schwannoma
Vestibular schwannomas, also known as acoustic neuromas, are relatively common tumors that arise from the vestibulocochlear nerve (CN VIII) and represent ~80% of cerebellopontine angle (CPA) masses. Bilateral vestibular schwannomas are strongly suggestive of neurofibromatosis type 2 (NF2).
On i...
Article
Acquired cholesteatoma
Acquired cholesteatomas are far more common than congenital cholesteatomas and are almost always closely related to the tympanic membrane and pneumatized portion of the temporal bone from which most are thought to arise 9.
Cholesteatomas occur far more commonly in the middle ear than in the ext...
Article
Acute mastoiditis
Acute mastoiditis refers to a suppurative infection of the mastoid air cells. It is the most common complication of acute otitis media.
Terminology
In acute otitis media, an inflammatory middle ear effusion is present that can freely move into the mastoid air cells. Consequently, some authors ...
Article
Adenomatoid odontogenic tumor
Adenomatoid odontogenic tumors are rare and differ from most other dentition related lesions in that they more frequently occur in the maxilla.
Epidemiology
They are also seen more frequently in females, most frequently in the second decade of life.
Radiographic features
They present as an e...
Article
Agger nasi cells
Agger nasi air cells are the most anterior ethmoidal air cells lying anterolateral and inferior to the frontal recess and anterior and above the attachment of the middle turbinate. They are located within the lacrimal bone and therefore have as lateral relations the orbit, the lacrimal sac and t...
Article
Ameloblastic fibroma
Ameloblastic fibromas appear as unilocular lucent mandibular lesions, most frequently in the posterior mandible, and are usually associated with impacted teeth, centered on the unerupted crown. They, therefore, appear very similar to unilocular ameloblastomas. They are composed of enamel and emb...
Article
Ameloblastoma
Ameloblastomas are locally aggressive benign tumors that arise from the mandible, or, less commonly, from the maxilla. They usually present as a slowly but continuously growing hard painless lesion near the angle of the mandible in the 3rd to 5th decades of life, which can be severely disfigurin...
Article
Arnold's nerve
Arnold's nerve, also known as the auricular branch or mastoid branch, of the vagus nerve (CN X) is a small sensory nerve supplying the skin of the external acoustic meatus.
Terminology
The greater occipital nerve has also been known in the past - confusingly - as the nerve of Arnold.
The use...
Article
Benign lymphoepithelial lesions
Benign lymphoepithelial lesions (BLL or BLEL), also misleadingly known as AIDS-related parotid cysts (ARPC), are mixed solid and cystic lesions that enlarge the parotid glands, and are usually associated with cervical lymph node enlargement, and nasopharyngeal lymphofollicular hyperplasia.
Term...
Article
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...
Article
Bill bar
Bill bar (TA: crista verticalis) also known as the vertical crest, is a bony anatomical landmark that divides the superior compartment of the internal acoustic meatus into an anterior and posterior compartment. Anterior to Bill bar, in the anterior superior quadrant, are the facial nerve (CN VII...
Article
Calcification of the globe (differential)
Calcification of the globe has many causes, varying from benign to malignant. When calcification is seen in the posterior half of the globe, it could relate to any of the layers (scleral, choroidal or retinal), as it is not possible to separate them out on CT.
Retinal
drusen: 1% population at ...
Article
Calcifying epithelial odontogenic tumor
Calcifying epithelial odontogenic tumor (CEOT), also known as a Pindborg tumor, (previously has been called adenoid adamintoblastoma, unusual ameloblastoma and cystic odontoma) is typically located in the premolar and molar region of the mandible, although up to a third are found in the maxilla....
Article
Capillary hemangioma of the orbit
Capillary hemangiomas of the orbit, also known as strawberry hemangiomas, on account of its coloring, or orbital infantile hemangiomas, are the most common orbital tumors of infancy, and unlike orbital cavernous hemangiomas, they are neoplasms rather than vascular malformations.
Clinical presen...
Article
Caroticocavernous fistula
Caroticocavernous fistulas represent abnormal communication between the carotid circulation and the cavernous sinus. They can be classified as direct or indirect which are separate conditions with different etiologies.
Epidemiology
Direct caroticocavernous fistulas are often secondary to tra...
Article
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...
Article
Cavernous sinus thrombosis
Cavernous sinus thrombosis (CST) is a rare condition, most commonly infectious in nature, and the diagnosis on imaging is not always straightforward. It has high mortality and morbidity rates.
Epidemiology
Cavernous sinus thrombosis is rare, with ~4.5 cases per 1,000,000 per year 5. It is the ...