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.
86 results found
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
Susceptibility vessel sign
The susceptibility vessel sign is a radiological sign appreciated on susceptibility-sensitive MRI brain sequences that is described in patients with acute ischemic stroke. It correlates well with the hyperdense vessel sign (e.g. hyperdense MCA sign) that may be seen on CT brain, but is considere...
Article
Mickey Mouse sign (disambiguation)
In medical imaging, a Mickey Mouse sign or appearance has been given to imaging features that mimic Mickey Mouse when viewed from the front. It has been described in the following:
anencephaly 2
progressive supranuclear palsy 1
synonymously with a finger in glove sign
the flared shape of the...
Article
String of pearls sign (disambiguation)
String of pearls sign can refer to:
string of pearls sign on an abdominal radiograph of fluid-filled dilated small bowel loops
string of pearls sign on brain MRI in deep border zone infarction
string of pearls sign on brain MRI in Susac syndrome
string of pearls sign on ultrasound in polycys...
Article
Sonographic halo sign (disambiguation)
Sonographic halo sign can be useful in a number of situations:
hypoechoic halo sign (also known as target or bull's eye sign) in liver metastases: used in hepatobiliary imaging, is a concerning feature for malignant lesion if the lesion is a hyperechoic liver lesion 1,2
ultrasound halo in angi...
Article
Beak sign (arterial dissection)
The beak sign of arterial dissection is the acute angle formed at the edge of the false lumen in aortic dissection in axial cross-section. It is formed by the borders of the outer aortic wall and the intimal flap, and may be partially thrombosed (blunted beak). It is a reliable characteristic th...
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
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
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
Hyperdense MCA sign (brain)
The hyperdense MCA sign, also known as Gács sign, is a type of hyperdense vessel sign and refers to focal hyperattenuation of the middle cerebral artery (MCA) on non-contrast brain CT and is due to intraluminal thromboembolic material. It is the earliest visible sign of MCA infarction and is see...
Article
Hypodense vessel sign
The hypodense vessel sign, or hypodense artery sign, is a radiological sign appreciated on non-contrast CT brain in acute ischemic stroke due to the rare entity of fat macroembolism causing large vessel occlusion. Notably, this is a distinct sign to the hyperdense vessel sign.
The sign describe...
Article
Hyperdense vessel sign
The hyperdense vessel sign is a radiological sign appreciated on non-contrast CT brain whereby there is focal hyperattenuation (mean of approximately 55 HU) within an intracranial blood vessel 1,2. Notably, this is a distinct sign to the hypodense vessel sign.
The hyperdense vessel sign is ofte...
Article
Disappearing basal ganglia sign
The disappearing basal ganglia sign is one of the early signs of a middle cerebral artery (MCA) infarction. It is defined as the loss of delineation of the basal ganglia, due to blurring of their grey-white matter interface and hypoattenuation, consequent to cytotoxic edema at the time of an isc...
Article
Cord sign (dural sinus thrombosis)
The cord sign is a type of hyperdense vessel sign and refers to cordlike hyperattenuation within a dural venous sinus on non-contrast enhanced CT of the brain due to dural venous sinus thrombosis. The sign is most commonly seen in the transverse sinus because along the origin of the tentorium it...
Article
Dense vein sign
The dense vein sign is a type of hyperdense vessel sign and refers to hyperattenuating thrombus within a cortical vein or dural venous sinus due to acute venous thrombosis.
When located in the superior sagittal sinus, particularly posteriorly, it is sometimes referred to as the delta, triangle ...
Article
MCA dot sign (brain)
The middle cerebral artery (MCA) dot sign, also known as the Sylvian fissure sign, is a type of hyperdense vessel sign seen on non-contrast brain CT and represents the cross-sectional M2 equivalent of the hyperdense MCA sign. Rather than imaging a length of middle cerebral artery (typically the ...
Article
Murphey's teat
Murphey’s teat, also known as Murphey’s tit or Murphey’s excrescence, refers to the cerebral angiographic finding of a focal outpouching within an intracranial aneurysm that indicates the likely site of rupture in a patient with subarachnoid hemorrhage 1,2. This sign, when present, is particular...
Article
Hair on end sign (mnemonic)
The hair on end sign refers to a radiographic appearance of the diploic space of the skull vault which results from a thickening of trabeculae as the diploic space expands. These trabeculae are perpendicular in orientation, interspersed by radiolucent marrow hyperplasia along with skull vault.
...
Article
Trident sign (persistent primitive trigeminal artery)
The trident sign of a persistent primitive trigeminal artery refers to the appearance of the intracranial circulation on lateral projection. The internal carotid artery, the abnormal vessel and superior portion of the basilar artery resemble the Greek letter tau (thus tau sign). This configurati...
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