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
Signs of pulmonary embolus on chest radiography
There are several described signs of pulmonary embolus on chest radiography which are suggestive of this diagnosis. None are pathognomonic and need to be interpreted with caution with close regard to the clinical presentation.
Chang sign
Fleischner sign
Hampton hump (strictly a sign of pulmon...
Article
Ependymal dot-dash sign
The ependymal dot-dash sign has been described as an early MRI imaging feature of multiple sclerosis before other more florid white matter changes (e.g. Dawson's fingers) become evident 1. It has also been suggested as a feature that can be used to distinguish multiple sclerosis from neuromyelit...
Article
Stag's antler sign (lungs)
The stag's antler sign, also known as the hands-up or inverted moustache sign, refers to upper lobe pulmonary venous diversion in pulmonary venous hypertension or pulmonary edema as seen on an erect frontal chest radiograph.
The prominence of upper lobe pulmonary veins resembles a stag's antler...
Article
Clot meniscus sign (angiography)
The clot meniscus sign, or simply the meniscus sign, is a radiological sign appreciated on digital subtraction angiography in the setting of endovascular clot retrieval for acute ischemic stroke caused by large vessel occlusion.
The sign describes the angiographic appearance of the proximal occ...
Article
Bagel sign (disambiguation)
A bagel sign has been named in multiple contexts:
bagel sign in MRI spine of neuro-Behçet disease-associated myelitis
bagel sign in ultrasound of tubal ectopic pregnancy
Article
Onion sign (disambiguation)
Due to its distinctive morphology and its layered internal structure the onion has given rise to a number of signs in imaging:
onion bulb appearance: Baló concentric sclerosis
onion bulb nerves: Charcot-Marie-Tooth type 1A and chronic inflammatory demyelinating polyneuropathies (CIDP)
onion ...
Article
Notch sign (primary CNS lymphoma)
The notch sign refers to an abnormally deep depression at the tumor margin in contrast-enhanced MRI in primary CNS lymphoma 1. It is not an uncommon sign in primary CNS lymphoma and can be seen in both immunocompetent and immunocompromised patients. It suggests an irregular growth pattern as wel...
Article
Ivy sign (brain)
The ivy sign refers to the MRI brain appearance of patients with moyamoya disease or moyamoya syndrome. Prominent leptomeningeal collaterals result in high signal on FLAIR due to slow flow and vivid contrast enhancement on post-contrast T1 1-3. The sign may be more reliably seen on post-contrast...
Article
Meniscus sign (disambiguation)
A meniscus sign has been named in multiple contexts:
air meniscus sign in chest imaging most commonly due to invasive aspergillosis 1
Carman meniscus sign in barium studies due to an ulcerated gastric cancer 2
clot meniscus sign in angiography due to large vessel occlusion acute ischemic stro...
Article
Claw sign (disambiguation)
A claw sign has been named in multiple contexts:
claw sign indicating the organ of origin of a mass
claw sign of degenerative spondylosis
claw sign in large vessel occlusion acute ischemic stroke
lobster claw sign of renal papillary necrosis
Article
Double beak sign
The double beak sign refers to the sudden tapering that two adjacent intestinal loops show in the internal hernia at the transition point of the closed loop obstruction.
The marked reduction in caliber results in distension of the afferent and efferent intestinal loops.
History and etymology
I...
Article
Flat tyre sign (globe rupture)
The flat tyre sign, also known as the mushroom sign, is one of the most specific signs of ruptured eye globe, due to the similarity between the abnormal contour of injured globe and the appearance of a flat tyre 1. It is classically described on CT but may be seen on ultrasound or MRI 2.
The mo...
Article
Boutonnière deformity
Boutonnière deformity is the eponymous name of a musculoskeletal manifestation of rheumatoid arthritis presenting in a digit, with the combination of:
flexion contracture of a proximal interphalangeal (PIP) joint
extension of a distal interphalangeal (DIP) joint
Pathology
Boutonnière deformi...
Article
Swan neck deformity (fingers)
Swan neck deformity is a musculoskeletal manifestation of rheumatoid arthritis presenting in a digit of the hand, due to the combination of:
hyperextension of a proximal interphalangeal (PIP) joint
flexion of a distal interphalangeal (DIP) joint
Pathology
The swan neck deformity, characteriz...
Article
Water lily sign (hydatid cyst)
The water lily sign, also known as the camalote sign, is seen in hydatid infections when there is detachment of the endocyst membrane which results in floating membranes within the pericyst that mimic the appearance of a water lily.
It is classically described on plain radiographs (mainly chest...
Article
Prominent vessel sign
The prominent vessel sign, or prominent hypointense vessel sign, is a radiological sign appreciated on susceptibility weighted imaging (SWI) that is described most commonly in patients with acute ischemic stroke.
The sign describes hypointense blooming artifact seen on SWI brain MRI within mult...
Article
Whirlpool sign (ovarian torsion)
The whirlpool sign or whirl sign of ovarian torsion is characterized by the appearance of a twisted ovarian pedicle, which can be seen on ultrasound, CT, and MRI 1,2.
Terminology
The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation).
Radiographic features
It...
Article
Whirlpool sign (mesentery)
The whirlpool sign of the mesentery, also known as the whirl sign, is seen when the bowel rotates around its mesentery leading to whirls of the mesenteric vessels.
Terminology
The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation).
Radiographic features
It is...
Article
Salted pretzel sign (CT head)
The salted pretzel sign is an uncommon sign of the presence of numerous small (<3 mm) calcific foci in the distal branches of a cerebral artery on non-contrast CT head that represent a shower of calcified cerebral emboli 1. Cerebral calcified emboli may be the initial manifestation of significan...
Article
Trethowan sign
The Trethowan sign is used to diagnose slipped capital femoral epiphysis (also called slipped upper femoral epiphysis). In this sign, the line of Klein passes above the femoral head 1.
It is best seen on the frontal projection 2. On the AP view of a normal hip, the Klein line intersects a small...
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