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
Lollipop sign (hepatic epithelioid hemangioendothelioma)
The lollipop sign is seen in hepatic epithelioid hemangioendothelioma (HEHE). It represents hepatic/portal vein and/or their tributaries/branches tapering and terminating at or just within the edge of a well defined peripherally enhancing (or non-enhancing) lesion with an avascular core on CT or...
Article
Toothpaste sign
The toothpaste sign in spinal imaging represents an extrusion of an intervertebral disc into the epidural space. It is called after the shape of extruded material relatively to the parent disc in a sagittal plane.
Article
Raccoon eyes sign (base of skull fracture)
Raccoon eyes sign (or panda eyes in the UK and Ireland) refers to periorbital ecchymosis with sparing of the tarsal plate 3 and is a physical examination finding indicative of a base of skull fracture of the anterior cranial fossa.
However it is not pathognomonic for trauma, and there are sever...
Article
Spinnaker sign (mediastinum)
The spinnaker sign (also known as the angel wing sign) is a sign of pneumomediastinum seen on neonatal chest radiographs. It refers to the thymus being outlined by air with each lobe displaced laterally and appearing like spinnaker sails. This is distinct from the sail sign appearance of the nor...
Article
Cloaca (osteomyelitis)
A cloaca (pl. cloacae or cloacas) is a gap in the cortex of a bone affected by chronic osteomyelitis that allows the drainage of pus or other material from the bone into the adjacent tissues.
Terminology
The use of the term cloaca should be reserved for cortical breaches that are the result of...
Article
Teardrop sign (superior mesenteric vein)
The teardrop sign of the superior mesenteric vein is one of the important signs in the local staging of pancreatic adenocarcinoma. Its importance lies in its diagnostic, as well as prognostic, significance. This sign is used in assessing the resectability of pancreatic cancer.
Radiographic feat...
Article
Pseudokidney sign (colonic carcinoma)
The pseudokidney sign is a non-specific sonographic sign that describes the reniform shape of a mass with a hypoechoic region (representing bowel wall thickening) surrounding a central hyperechoic portion or echogenic stripe (which represents the apposition of the mucosal surfaces) 1,2.
It can...
Article
Flashlight sign (B-flow)
The flashlight sign is a B-flow vascular ultrasound sign caused by wall adherent and floating thrombi and emboli in arteries, which appear as bright spots on imaging.
Radiographic features
Ultrasound
The flashlight sign is described as a moving, very bright intraluminal focus of signal on B-f...
Article
Charcot triad
Charcot triad is the finding of pyrexia, right upper quadrant pain and jaundice, and is a traditional clinical sign of acute cholangitis.
A meta-analysis of 4288 patients in 16 studies found that the sensitivity of Charcot triad for acute cholangitis was poor (36.3%) with a much better specific...
Article
Antral nipple sign (pyloric stenosis)
The antral nipple sign refers to redundant pyloric mucosa protruding into the gastric antrum and is seen in hypertrophic pyloric stenosis on ultrasound examination.
See also
cervix sign (pyloric stenosis)
target sign (pyloric stenosis)
Article
Apple core sign (femur)
The apple core sign has been used to describe the circumferential erosion of the femoral neck seen in synovial chondromatosis. Although this is the most common process that may lead to an apple core erosion of the femoral neck, this sign has also been observed with various pathological processes...
Article
Black hole sign (intracerebral hemorrhage)
The black hole sign refers to the non-contrast CT appearance of acute extravasation of blood into a hematoma, for example, an intracerebral hemorrhage, and therefore is a predictor of hemorrhage expansion 3. It can be thought of as an encapsulated swirl sign.
Radiographic features
The black ho...
Article
Perilymphatic fistula
A perilymphatic fistula (also known as a labyrinthine fistula) is a pathologic communication between the fluid-filled space of the inner ear and the air-filled space of the middle ear, most commonly occurring at either the round or oval window.
Clinical presentation
Symptoms of perilymphatic ...
Article
Napkin-ring sign (heart)
The napkin-ring sign is a feature of high-risk coronary artery atherosclerotic plaque on CT coronary angiogram (coronary CTA). It has been shown to possess a high predictive value in predicting future cardiac events and is considered one of the imaging correlates of an unstable plaque. It is one...
Article
Crescent sign of arterial dissection
The crescent sign refers to the high signal crescent seen in the wall of a vessel when dissected. This may be seen both on T1 or T2 sequences depending on the age of the blood (see aging blood on MRI). It is classically referred to in internal carotid artery dissection.
It should not be confuse...
Article
Stener-like lesion of the medial collateral ligament of the knee
Stener-like lesions of the medial collateral ligament (MCL) occur when a tear involves the distal fibers of the superficial medial collateral ligament (sMCL) are displaced superficially to the pes anserinus, which can result in compromised healing.
Pathology
Usually, the sMCL runs deep to the p...
Article
Athelia
Athelia is a rare congenital condition characterized by the absence of the nipple. This may occur unilaterally or bilaterally.
Associations
Poland syndrome
ectodermal dysplasia 2
Article
Absent bow tie sign (knee)
The absent bow tie sign represents the loss of the normal appearance of the menisci on parasagittal MRI images and is suggestive of meniscal injury.
Normally the medial and lateral menisci appear as low signal triangular structures linked by a thin body located between the femoral condyles and ...
Article
Tulip bulb sign
The tulip bulb sign refers to the characteristic appearance of annuloaortic ectasia as seen on CT angiography.
There is symmetric dilatation of the three sinuses of Valsalva, with extension into the ascending aorta and effacement of the sinotubular junction.
It is seen especially in Marfan sy...
Article
Vertebral body squaring (differential)
Vertebral body squaring refers to the loss of normal concavity of the anterior border of the vertebral body. It is seen in a variety of conditions, some of which are listed below.
Differential diagnosis
Ankylosing spondylitis
Ankylosing spondylitis is the most common cause of vertebral body ...
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