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.
1,141 results found
Article
Pseudodysraphism
A pseudodysraphism refers to the splayed appearance of a normal spine created due to excessive craniocaudal angulation during sonographic evaluation. This can erroneously lead to the diagnosis of a spinal neural tube defect.
Article
Pneumolipohaemarthrosis
Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohemarthrosis. It indicates an open intra-articular fracture.
Article
Phantom calyx
A phantom calyx is a solitary calyx which fails to opacify with contrast amidst an otherwise well-opacified pelvicalyceal system. It is due to an intrarenal process which has infiltrated and caused obliteration of the involved collecting system element.
It may be seen in:
tumor: especially tra...
Article
Perirenal cobweb
Perirenal cobwebs are the presence of prominent perinephric septa. It is best appreciated on CT images.
Pathology
The cobweb is considered to be due to engorged venous collaterals or due to edema and fluid extravasation into the perirenal space 1.
Perirenal cobwebs may be seen in many benign ...
Article
Fleischner sign (disambiguation)
Fleischner sign can refer to two distinctly separate signs:
Fleischner sign (enlarged pulmonary artery)
Fleischner sign (tuberculosis of ileocecal junction)
Article
Infundibulum sign (pituitary)
The infundibulum sign is helpful in distinguishing an empty pituitary sella from a cystic lesion of the pituitary region 1.
In the former, although the sella is enlarged, there is no mass as such and the pituitary infundibulum traverses the enlarged sella to its floor where residual pituitary ...
Article
Lhermitte sign (spinal cord)
Lhermitte sign or the barber chair phenomenon is an electrical shock sensation running down the spine and into the limb on neck flexion. It suggests compression of the upper cervical spinal cord and/or brainstem.
Pathology
It is typically seen with multiple sclerosis but is also associated wit...
Article
Adie pupil
Adie pupil (also known as tonic pupil) is caused by idiopathic degeneration of the ciliary ganglion, which sometimes occurs following a viral or bacterial illness. It is usually unilateral and typically affects young females 1.
Adie pupil represents a large dilated "tonic pupil", which does not...
Article
Panzerherz (heart)
Panzerherz (or armoured heart) is a term used to describe the appearance of the heart in calcified constrictive pericarditis.
The pericardium becomes circumferentially thickened with calcification, limiting the ability of the heart to contract. The rim of dense calcification describes how the h...
Article
Lucent liver sign
The lucent liver sign is represented by a reduction of hepatic radiodensity on supine radiograph when there is a collection of free intraperitoneal gas located anterior to the liver.
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Lateral crescent sign (inguinal hernia)
The lateral crescent sign is a useful diagnostic sign of a direct inguinal hernia on CT scan, the hernia causing compression and lateral displacement of the inguinal canal contents (ductus deferens, testicular vessels, fat, etc.) to form a semicircle of tissue that resembles a moon crescent seen...
Article
Hyoid elevation
Hyoid elevation on a modified barium swallow study indicates that the pharyngeal muscles are contracting appropriately.
Radiographic features
Modified barium swallow
With real time fluoroscopy (or videofluoroscopy) during the act of swallowing, the larynx moves upward and forward when there i...
Article
Onion peel sign
The onion peel sign (also called the Cumbo sign or double arch sign) is a feature seen with complicated pulmonary hydatid cyst in which the gas lining between the endocyst and pericyst has the appearance of an onion peel. It is pathognomonic for a ruptured hydatid cyst.
History and etymology
I...
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Hutchinson teeth
Hutchinson teeth are smaller and more widely spaced than normal and are notched on their biting surfaces.
It is a sign of congenital syphilis and should not be confused with:
Hutchinson triad
Hutchinson pupil
Hutchinson freckle
Hutchinson sign
Hutchinson syndrome
History and etymology
Na...
Article
Hutchinson pupil
Hutchinson pupil is a fixed and dilated pupil caused by compression of the oculomotor nerve (CN III) as a result of uncal herniation.
It should not be confused with any of the following:
Hutchinson triad
Hutchinson freckle
Hutchinson teeth
Hutchinson sign
Hutchinson syndrome
History and e...
Article
Hampton line
The Hampton line is a thin millimetric radiolucent line seen at the neck of a gastric ulcer in barium studies (profile view), indicating its benign nature. It is caused by a thin line of mucosa overhanging the ulcer's crater.
History and etymology
It was originally described by Aubrey Otis Ham...
Article
Guttman test (larynx)
The Guttman test is a clinical test relating to the function of the larynx.
In normal subjects, frontal pressure on the thyroid cartilage lowers the tone of voice produced and lateral pressure produces a higher tone of voice. The opposite is true with paralysis of the cricothyroid muscle.
Article
Ghost sign (cervical spine)
The ghost sign is a feature that has been described in a clay shoveler fracture as seen on the AP projection of a cervical spine radiograph. It is caused by the appearance of a "double spinous process" on C6 or C7 resulting from caudal displacement of the avulsed spinous process fragment, giving...
Article
Funnel trachea
Funnel trachea is a colloquialism for a congenital long-segment intrathoracic tracheal stenosis.
The diameter of the trachea immediately below the cricoid is normal, and becomes progressively more stenotic caudally. The posterior, membranous portion of the trachea may be partially or completel...
Article
Floating head appearance
A floating head appearance refers to imaging features observed typically on antenatal ultrasound with certain skeletal dysplasias such as achondrogenesis.
Against the background of a poorly-mineralized spine, a normally ossified skull is seen giving an impression of a floating head.
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