6,134 results
Article
Thymic sail sign
The thymic sail sign represents a triangular-shaped inferior margin of the normal thymus seen on a neonatal frontal chest radiograph. It is more commonly seen on the right side, but can also be bilateral. It is seen in 3-15% of all cases. This sign should not be confused with the spinnaker sail ...
Article
Halo sign (chest)
The halo sign in chest imaging is a feature seen on lung window settings, ground glass opacity surrounding a pulmonary nodule or mass and represents hemorrhage. It is typically seen in angioinvasive aspergillosis.
Pathology
Histopathologically, it represents a focus of pulmonary infarction sur...
Article
Thumb sign (epiglottitis)
The thumb sign in epiglottitis is a manifestation of an edematous and enlarged epiglottis which is seen on lateral soft-tissue radiograph of the neck, and it suggests a diagnosis of acute infectious epiglottitis. This is the radiographic corollary of the omega sign 1-3.
See also
Thumb sign is ...
Article
Doughnut sign (orbit)
The doughnut sign of optic nerve sheath meningioma refers to the appearance of this tumor on coronal CT/MRI. The meningioma forms a thick cuff of enhancing tumor around the central non-enhancing optic nerve, mimicking the appearance of a ring doughnut. It is the coronal equivalent of the tram-tr...
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
Open ring sign
The open ring sign is a relatively specific sign for demyelination, most commonly multiple sclerosis (MS), and is helpful in distinguishing between the causes of ring-enhancing lesions.
Radiographic features
The enhancing component is thought to represent advancing front of demyelination and ...
Article
Double line sign
The double line sign is a pathognomonic MRI finding seen at the periphery of a region of osteonecrosis or bone infarct, representing the border between the viable and non-viable bone 4. It is best seen on T2 and T2 FS sequences and consists of two serpentine lines: an inner bright line represent...
Article
Twin peak sign
The twin peak sign, also known as the lambda (λ) sign, is the triangular appearance of the chorion insinuating between the layers of the intertwin membrane and strongly suggests a dichorionic diamniotic twin pregnancy. It is best seen in the first trimester (between 10-14 weeks) 5. While the pre...
Article
Cockade sign (disambiguation)
There are several described cockade signs in radiology:
cockade sign (aorto-left ventricular tunnel) 1
cockade sign (appendicitis) 2
cockade sign (GI tumors) 4
cockade sign (hypertrophic pyloric stenosis) 3
cockade sign (intraosseous lipoma)
History and etymology
It is named after a cocka...
Article
Whirlpool sign (disambiguation)
The whirlpool sign, also known as the whirl sign, is seen when a structure twists upon itself resembling the rotating masses of water of a whirlpool. Described whirlpool signs include:
whirlpool sign (mesentery): bowel rotates around its mesentery leading to whirls of the mesenteric vessels
w...
Article
Central dot sign
The central dot sign represents the telltale appearance of intrahepatic portal vein branches surrounded by severely dilated bile ducts, which can be visualized by either CT, MRI, or US.
Pathology
The central dot sign is primarily encountered in congenital intrahepatic bile duct dilatation (Car...
Article
Metaphyseal blanch sign
The metaphyseal blanch sign (or metaphyseal blanch sign of Steel) is one of the signs seen on AP views of the adolescent hip indicating posterior displacement of the capital epiphysis.
It is a crescent-shaped area of increased density, that overlies the metaphysis adjacent to the physis on the ...
Article
Trident sign (neurosarcoidosis)
The trident sign is a radiological (MRI) sign described in spinal cord neurosarcoidosis.
The sign is formed by the axial appearance of a longitudinally extensive transverse myelitis due to spinal cord neurosarcoidosis, whereby on a T1 post-contrast (gadolinium) MRI sequence, there is central ca...
Article
Cingulate island sign
The cingulate island sign is a highly specific radiological sign described in dementia with Lewy bodies.
It refers to the pattern of metabolism seen on FDG-PET in patients with dementia with Lewy bodies 1-3. On FDG-PET, there is occipital hypometabolism with relative sparing of the posterior ci...
Article
Hilum overlay sign
The hilum overlay sign is useful in differentiating whether an opacity on a frontal chest radiograph in the region of the lung hilum is located within the hilum versus anterior or posterior to it. The sign refers to preserved visualization of the hilar vessels, excluding abnormalities that local...
Article
Double panda sign
The double panda sign refers to the combination of the face of the giant panda and face of the miniature panda (cub of the giant panda) seen on T2 weighted images of midbrain and pons respectively, most commonly seen in Wilson disease.
The midbrain face of the giant panda sign consists of norma...
Article
Positive carpal sign
The positive carpal sign is a useful radiographic sign for the diagnosis of Turner syndrome in association with other musculoskeletal manifestations. Abnormality in the shape of the proximal carpal row in the dorsopalmar radiographs of the wrist and hand (taken in the neutral position is key to ...
Article
Snowman sign (disambiguation)
Snowman sign, also sometimes referred to as a figure of 8 sign or dumbell sign, is a radiologic sign related to conditions that have a shape which resembles a snowman. This include:
snowman sign (total anomalous pulmonary venous return) 1
snowman sign (pituitary macroadenoma) 2,3
Article
Double doughnut sign
The double doughnut sign, or double-doughnut sign, is a radiological sign described in MRI of viral encephalitis, typically due to dengue encephalitis.
The double doughnut sign refers to a pattern of signal changes in the bilateral thalami that have a doughnut-like appearance 1-4. This sign is ...
Article
Dagger sign (spine)
The dagger sign is a radiographic feature seen in ankylosing spondylitis as a single central radiodense line on frontal radiographs related to ossification of the supraspinous and interspinous ligaments secondary to enthesitis 1. It is possible for the radiodense line to extend into the sacrum 2...
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