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Rose-thorn ulcers (terminal ilium)

Rose-thorn ulcers or rose-thorn appearance refers to deep penetrating linear ulcers or fissuring typically seen within stenosed terminal ileum with a thickened wall. They appear as thorn-like extraluminal projections on barium studies and this appearance is one of the typical signs of Crohn dise...

Battle sign (base of skull fracture)

Battle sign is an eponymous term given to mastoid ecchymosis (bruising of the scalp overlying the mastoid process) and is strongly suggestive of a base of skull fracture, most commonly a petrous temporal bone fracture. History and etymology Mr William Henry Battle (1855-1936) was an English s...

Flip-flop effect

The so-called flip-flop effect refers to a confusing MRI appearance of the skeletal system and subcutaneous tissues. It is seen in a variety of severe fat depletion conditions responsible for diffuse bone marrow serous atrophy and modification or loss of the subcutaneous fat. It is not to be co...

Triple bubble sign

The triple bubble sign is the classic radiographic appearance observed in jejunal atresia 1,2. The appearance is due to a proximal obstruction caused by the atretric jejunum. It is equivalent to the double bubble sign, but a third bubble is seen because of proximal jejunal distention.

Intrabiliary rupture of hepatic hydatid cyst

Intrabiliary rupture of hepatic hydatid cyst is a common complication associated with hepatic hydatid cysts. It is important to appreciate the direct and indirect signs of this condition. Radiographic features The radiological features of intrabiliary rupture of a hepatic hydatid cyst can be c...

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...

Argyll Robertson pupil

Argyll Robertson pupil is usually bilateral and presents as bilaterally miotic and irregular pupils, which constrict briskly with accommodation but do not react to bright light therefore displaying light-near dissociation 1. It is a highly specific sign of late neurosyphilis, however can also ...

Periportal free gas sign

The periportal free gas sign has been described as being strongly suggestive for upper gastrointestinal tract perforation. See also bowel perforation (summary) pneumoperitoneum

Cortical vein sign

The cortical vein sign refers to the presence of superficial cortical veins seen on MRI and CT (particularly with contrast injection) traversing an enlarged subarachnoid space, differentiating it from the similar radiological appearance of a subdural hygroma. Although initially proposed as a me...

Angular interface sign

The angular interface sign is used to characterize an exophytic renal mass, in which the exophytic renal mass has an angular interface with the renal parenchyma. In other words, the exophytic lesion has a tapered pyramidal contour or definite apex within the renal parenchyma. Due to its high se...

Sail sign (disambiguation)

There are numerous sail signs in radiology, where a normal structure is displaced or a pathology creates the appearance of a sail: elbow sail sign: the raised anterior fat pad on an elbow radiograph thymic sail sign: normal thymus on a pediatric chest radiograph spinnaker-sail sign (angel win...

Right posterior hepatic notch sign

The right posterior hepatic notch sign is a sharp indentation of the normally smooth posterior right hepatic lobe margin. It is associated with cirrhosis, although the mechanism is not entirely clear. It has been suggested that this may be an indication of relative caudate lobe hypertrophy and d...

Signs article structure

Articles on signs are in general short articles and do not usually require subheadings. ======================================================================= Signs are numerous in radiology and typically relate to a specific appearance or feature that is reminiscent of an object. A named sig...

Grey cortex sign (stress fracture)

The grey cortex sign was described as an early sign of stress (fatigue) fractures on plain radiographs and refers to subtle ill-definition/lucency of the cortex at the site of microfracture. However, plain radiography is insensitive (~25%, range 15-25%) for the detection of early-stage injuries....

Double Oreo cookie sign (glenoid labrum)

The double Oreo cookie sign refers to the presence of two hyperintense lines in the superior glenoid labrum, one of which represents a superior labral tear and the other a physiological sublabral recess 1,2. Terminology This sign should not be confused with the Oreo cookie sign of pericardial ...

Sliver sign (patella)

The sliver sign refers to a curvilinear intra-articular osteochondral fragment in the knee joint on conventional knee radiographs. In the context of acute knee trauma and in association with joint effusion this sign is highly predictive of a recent transient lateral patellar dislocation 1. Path...

Broken heart sign

The broken heart sign, also known as the Y sign in older otorhinolaryngology literature 2,3, describes the appearances of incudomalleolar disarticulation. This sign is identified on CT in the coronal plane, being formed by the widening of the incudomalleolar joint and lateral displacement of th...

Martini glass sign

The Martini glass sign describes the appearance of the globe in persistent hyperplastic primary vitreous (PHPV). On MRI the retrolenticular tissue characteristic of this condition has a triangular shape, like that of a martini glass appearing as low T2 signal against the normal high T2 signal o...

Matterhorn sign

The Matterhorn sign is a descriptive sign for a calcified disc herniation that impales the dural sac and sometimes the cord, typically located in the thoracic spine. History and etymology This sign is named after one of the most iconic mountains in the Alps: the Matterhorn.

Hockey stick sign (thyroid hemiagenesis)

Hockey stick sign has been used to describe the appearance of the thyroid gland in cases of thyroid hemiagenesis when investigated with thyroid scan (Tc-99m) 1. The unilateral lobe and isthmus make a shape reminiscent of a hockey stick. See also hockey stick sign (Creutzfeldt-Jakob disease)

Rat bite erosions (gout)

Rat (or mouse) bite erosions, also known as Martel sign or G sign, are seen in gout and refer to punched out erosions with sclerotic and overhanging margins. History and etymology This characteristic presence of the overhanging margin associated with the erosion in gout was first described by ...

Bird beak sign (disambiguation)

Bird beak sign is used in many contexts to denote a rapid tapering to a point, reminiscent of a bird's beak. Described bird beak signs include: beak sign (arterial dissection) beak sign (pyloric stenosis) bird beak sign (esophagus) bird beak sign (right colon) bird beak sign (sigmoid colon...

Zebra sign (cerebellum)

The zebra sign has been termed to describe the finding of layering of blood in amongst the folia of the cerebellum, particularly in the setting of supratentorial surgeries (temporal lobe resection), neuro-vascular neck surgeries, lumbar spinal surgeries possibly secondary to dural tear and inter...

Thoracic spine sign (ultrasound)

The thoracic spine sign, or spine sign, on lung ultrasound is an indirect indicator of the presence of a pleural effusion or hemothorax. It represents the visualization of the vertebral bodies in the thoracic cavity above the diaphragm which are usually not seen unless there is a fluid collectio...

Thurstan Holland fragment

The Thurstan Holland fragment (or Thurstan Holland sign) is an eponymous radiological sign depicting a triangular portion of the metaphysis remaining with the epiphysis in a physeal fracture. This fragment indicates that a type 2 Salter-Harris fracture has occurred 1. History and etymology It...

Hemorrhage exclusion sign (prostate)

The hemorrhage exclusion sign can be a useful MRI finding following prostate biopsy. Pathology The normal prostate produces high concentrations of citrate, which among other properties, acts as an anticoagulant 1. As tumor cells are dysfunctional, they will produce lower levels of citrate than...

Steinberg sign (Marfan disease)

The Steinberg sign, also known as the thumb sign, is one of the clinical examination tests for Marfan disease in the hands. It is a clinical test in which the tip of the thumb is visible medial to the little finger when it is clasped in the clenched hand. See also thumb sign (disambiguation)

Thumb sign (disambiguation)

The term thumb sign is used to refer to a number of separate radiological appearances, including: thumb sign (Marfan disease) - a clinical sign thumb sign (epiglottitis) thumb sign (chordoma)

Temporal tap maneuver

Temporal tap maneuver consists in tapping over the ipsilateral superficial temporal artery while assessing the carotid bifurcation on Doppler ultrasound aiming to produce a reflected flow in the external carotid artery (ECA) and thus helping to distinguish which vessel is being assessed: externa...

Mercedes-Benz sign (disambiguation)

The Mercedes-Benz sign can refer to different anatomical structures or signs: Mercedes-Benz sign (gallbladder) Mercedes-Benz sign (aorta) If this is not confusing enough as it is, there is also the more recently coined inverted Mercedes-Benz sign

Patent track sign (ultrasound)

Patent track sign is a finding on color Doppler ultrasound, representing blood traveling along the course a biopsy needle track. It can occur after a biopsy of any organ, but is more often seen after liver or kidney biopsies. Radiographic findings linear color Doppler flow along the course of ...

Lincoln sign on bone scintigraphy

Lincoln sign on bone scintigraphy (also known as black beard sign) is one of the signs of Paget disease on the radionuclide bone scan when the disease involves the mandible. The sign might be seen when the extensive mandibular involvement with Paget disease results in the uptake of the radiotrac...

Garrington sign (teeth)

Garrington sign is thickening of the periodontal ligament/membrane space of involved teeth in the setting of gnathic osteosarcoma. Symmetrical widening of the space can be seen early in the disease process due to infiltration of tumor cells.

X-marks-the-spot sign (large bowel volvulus)

The X-marks-the-spot sign of large bowel volvulus refers to the crossing loops of the bowel at the site of the transition. It has been reported to improve diagnostic confidence in detecting cecal and sigmoid volvulus. This is in contrast to the split-wall sign which indicates partial obstruction...

Bird beak sign (sigmoid colon)

Bird's beak sign of the sigmoid is one of the signs of sigmoid volvulus. It represents gradual narrowing/tapering of the sigmoid colon up to the level of obstruction during contrast/barium insertion to the rectum or on CT. When located in the sigmoid colon, it suggests the diagnosis of sigmoid ...

Fluid bronchogram sign

The fluid bronchogram sign can be seen on chest CT or ultrasound as the presence of fluid attenuation material within respiratory bronchioles with surrounding collapsed or consolidated lung. The presence of this sign suggests endobronchial obstruction as a precipitating cause for consolidation/...

Ball of wool sign (hydatid cyst)

The ball of wool sign, also referred to as the yarn sign or congealed water lily sign, is an ultrasound appearance, representing degeneration of hydatid cysts (WHO class CE 4). The inner side of the cyst detaches from the cyst wall and folds on itself, causing a change from anechoic (fluid) to a...

U sign (central sulcus)

The U sign denotes the characteristic U-shaped appearance of the subcentral gyrus which surrounds the inferolateral end of the central sulcus and abuts the lateral (Sylvian) fissure. It has been found, at least in one study, to be the most reliable anatomical feature to identify the central sulc...

Bracket sign (pars marginalis)

The bracket sign of the pars marginalis, also known as the pars bracket sign, refers to the appearances of the superior most extent of the pars marginalis of the cingulate sulcus on axial imaging. It forms two roughly symmetric brackets, open anteriorly. The next sulcus anteriorly is the central...

M sign (inferior frontal gyrus)

The M sign refers to the characteristic "M" configuration of the inferior frontal gyrus, as it forms (from front to back) the pars orbitalis, pars triangularis, and, pars opercularis.

L sign (brain)

The L sign is one of the features useful in identifying the central sulcus on cross-sectional imaging. On axial images, the superior frontal gyrus at its posterior aspect meets the precentral gyrus in an "L" configuration (forwards on the left, backward on the right). The central sulcus is the ...

Lower T sign (central sulcus)

The lower T sign is one of the features useful in identifying the central sulcus on cross-sectional imaging. It relies on identifying the inferior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulcus is the next posteri...

Upper T sign

The upper T sign is one of the features useful in identifying the central sulcus of the cerebral cortex on cross-sectional imaging. It relies on identifying the superior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulc...

Pneumolipohaemarthrosis

Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohemarthrosis. It indicates an open intra-articular fracture.

Teardrop (disambiguation)

A teardrop or teardrop sign is used in several regions of the body: extension teardrop fracture of the cervical spine flexion teardrop fracture of the cervical spine pelvic teardrop teardrop sign (ankle) teardrop sign (inferior orbital wall fracture) teardrop sign (intracapsular breast imp...

Bird beak sign (right colon)

The bird beak sign of the right colon is tapering obstruction of the inferior part of right colon seen on contrast enema or CT scan with rectal contrast indicating cecal volvulus. This sign can help to differentiate cecal volvulus from cecal bascule, in particular on a contrast/barium enema stu...

Inverted "V" sign (pneumoperitoneum)

The inverted "V" sign, also known as the lateral umbilical ligament sign, is a sign of pneumoperitoneum manifested by the visualization of an inverted "V" shape in the pelvis on supine view of abdominal radiographs. It represents free gas outlining the lateral umbilical ligaments. In infants, t...

Tram-track sign (brain)

Tram-track sign in the brain refers to the parallel calcification of the cortex in patients with Sturge-Weber syndrome 1. It should not be confused with other tram-track signs elsewhere in the body.

Stepladder sign (disambiguation)

Stepladder sign may refer to: intracapsular breast implant rupture (ultrasound) gas-fluid levels in obstructed small bowel (erect abdominal radiograph)

Stepladder sign (small bowel obstruction)

Stepladder sign represents the appearance of distended small bowel loops with gas-fluid levels that appear to be stacked on top of each other, typically observed on erect abdominal radiographs in the setting of small bowel obstruction.

Salad oil sign

The salad oil sign, also referred to as the droplet sign, is an MRI sign of breast implant rupture. It is characterized by small rounded high T2 signal foci within a breast implant and represents water droplets or small amounts of gas within the silicone. It also can be characterized as hypoint...

Snowstorm sign (disambiguation)

Snowstorm sign may refer to: snowstorm sign: complete hydatiform mole (ultrasound) snowstorm sign: extracapsular breast implant rupture (ultrasound) snowstorm sign: thyroid pulmonary metastases (chest radiograph)

Snowstorm sign (extracapsular breast implant rupture)

The snowstorm sign on breast ultrasound imaging represents the presence of free silicone droplets mixed with breast tissue giving a characteristic heterogeneous echogenic appearance with dispersion of the ultrasound beam. It is considered the most reliable sign of extracapsular breast implant ru...

Turtleback sign

Turtleback sign, also known as tortoise shell appearance, represents a characteristic appearance of chronic hepatic schistosomiasis in which liver margins are irregular and nodular. Dystrophic calcifications within a polygonal network of fibrous septa are seen in the periphery, often perpendicul...

Caton-Deschamps index (knee)

The Caton-Deschamps index is used to measure patellar height and identify patella alta and patella baja. The Caton-Deschamps index relies upon the length of the patellar articular surface and its distance from the tibia, reducing erroneous measurements in those with long patella bodies, as measu...

Delayed nephrogram

A delayed nephrogram, commonly described on plain film urography, but also visible on CT urography, is when there is absence or reduction of the normal renal parenchymal enhancement on the nephrographic phase images. Terminology A delayed nephrogram is characteristically unilateral and is usua...

Windsock sign (aortic dissection)

The windsock sign refers to appearances seen in type A thoracic aortic dissections on contrast CT. It results from intimointimal intussusception between the true and false dissected lumens of the thoracic aorta. The altering density of contrast between the dissection lumens which taper distally ...

Fat stranding (CT)

Fat stranding is a common sign seen on CT wherever fat can be found. It is most commonly seen in abdomen/pelvis, but can also be seen in retroperitoneum, thorax, neck and subcutaneous tissues. It can be helpful in localizing both acute and chronic pathology. Radiographic features CT Fat stran...

Fat stranding (summary)

This is a basic article for medical students and other non-radiologists Fat stranding is a sign that is seen on CT. It describes the change in attenuation of fat around an inflamed structure and is a very helpful signpost for intra-abdominal pathology. Reference article This is a summary arti...

Mercedes-Benz sign (aorta)

The Mercedes-Benz sign can be seen in aortic dissection on CT 1. It is seen as three distinct intimal flaps that have a triradiate configuration similar to the Mercedes-Benz logo (Figure 1). Two of the three lumens outlined by these intimal flaps belong to the false lumen of aortic dissection....

Double target sign (hepatic abscess)

The double target sign is a characteristic imaging feature of liver abscess on contrast-enhanced CT scans, in which a central, fluid-filled low attenuation lesion is surrounded by a high attenuation inner rim and a low attenuation outer ring 1,2. The inner ring (abscess membrane) demonstrates e...

Zebra spleen

Zebra spleen, also referred to as psychedelic spleen, tigroid splenic enhancement or more correctly inhomogeneous splenic enhancement, refers to the transient heterogeneous parenchymal enhancement of the spleen during the arterial or early portal venous phases of contrast enhancement in CT, MRI,...

Middle cerebellar peduncle sign

The middle cerebellar peduncle (MCP) sign is a feature of a number of conditions, particularly neurodegenerative diseases, and most commonly associated with fragile X-associated tremor/ataxia syndrome (FXTAS) although many other conditions are recognized. It represents high T2 signal in the mi...

Thrombus fissuration sign (aortic aneurysm)

Thrombus fissuration is a sign of impending rupture of an aortic aneurysm. It reflects blood dissecting into the intramural thrombus. This sign is observed on contrast-enhanced CT as a linear contrast infiltration from the aneurysm lumen through the intramural thrombus. Thrombus fissurations ext...

Jejunoileal fold pattern reversal

Jejunoileal fold pattern reversal (a.k.a. jejunization of the ileum) is one of the signs of celiac disease, and is seen on small bowel follow-through studies, CT and MRI 1-4. The pattern is one of increased number of ileal folds and reduced number of jejunal folds 1,2, and is considered positive...

Posterior fat pad sign (elbow)

The posterior fat pad sign is the visualization of a lucent crescent of fat located in the olecranon fossa on a true lateral view of an elbow joint with the elbow flexed at a right angle indicating an elbow joint effusion. Normally, the posterior fat pad will not be seen in this view ref. In t...

Lung point sign

The lung point sign is a highly specific ultrasound sign of pneumothorax. It involves visualizing the point where the visceral pleura (lung) begins to separate from the parietal pleural (chest wall) at the margin of a pneumothorax. In the absence of pneumothorax, the two pleural layers slide a...

Dog leg sign (popliteal artery)

The "dog leg" sign is a secondary angiographic sign on popliteal angiography, which demonstrates an irregular lumen of the popliteal artery with acute bend in the course of the popliteal artery. It is characteristically seen in popliteal artery aneurysms with mural thrombus. It is an important ...

Floating viscera sign

The floating viscera sign is an angiographic sign that occurs when there is visualization of branches of the abdominal aorta (e.g. celiac axis, superior mesenteric artery, and renal arteries) during aortography with little or no visualization of the aortic lumen. The floating viscera sign indic...

Boomerang sign (knee)

The boomerang sign is defined as a small displaced flap from a longitudinal horizontal type medial meniscal tear which is displaced inferiorly into the medial meniscotibial recess. The imaging diagnosis of this type of tear is crucial because it is normally hidden from the surgeon during routine...

Jack and Jill lesion

The Jack and Jill lesion refers to simultaneous bucket handle tears of the medial and lateral menisci with intercondylar notch displacement of the fragments which appear as the quadruple sign on coronal MRI images.

Owl-eyes sign (spinal cord)

The owl-eyes sign, also known as snake-eyes sign or fried-eggs sign, represents bilaterally symmetric circular to ovoid foci of high T2-weighted signals in the anterior horn cells of the spinal cord and is seen on axial MR imaging. The sagittal corollary is a "pencil-like" vertical linear high T...

Fascial tail sign

The fascial tail sign refers to the linear/tapered extension of soft tissue tumors along the fascia. The sign has been classically described in benign fibrous proliferations 1-4: desmoid tumor plantar fibromatosis nodular fasciitis However, the same sign has also been described as the tail ...

Double contour cartilage line

The double contour cartilage line is a sonographic sign specific for gout, which is characterized by an echogenic line on the outer surface of the joint cartilage parallel to the subchondral bone secondary to deposition of monosodium urate crystals on the surface of hyaline articular cartilage.

Ice pick sign

The ice pick sign is a smooth tapered narrowing of the upstream pancreatic duct distal to the pancreatic lesion seen frequently in benign pancreatic lesions such as a focal autoimmune pancreatitis, this is due to the extrinsic narrowing of the duct secondary to periductal fibrosis and inflammati...

Pseudopneumomediastinum

Pseudopneumomediastinum is the false impression, usually on a chest x-ray, of pneumomediastinum. Correctly identifying pneumomediastinum is important, but making the diagnosis in error may lead to further unnecessary investigation and possible treatment. Causes include: Mach band superimposed...

Higoumenakis sign (clavicle)

The Higoumenakis sign is the unilateral enlargement of the sternal end of the clavicle in patients with late congenital syphilis. It was originally described as a clinical sign on physical examination but can also be recognized on chest radiograph 5. Pathology Treponema pallidum becomes readil...

Gage sign

The Gage sign is a V-shaped lucent defect at the lateral portion of the epiphysis and/or adjacent metaphysis. It is pathognomonic for Legg-Calve-Perthes disease. It may occur early in the disease and is one of the five indicators of a worse prognosis, which are: Gage sign calcification latera...

Third mogul sign

The third mogul sign can be seen on frontal chest radiograph in the presence of left atrial enlargement. It refers to an extra mogul or bump along the upper left cardiac silhouette just below the left main bronchus. The third mogul sign commonly represents the enlarged left atrial appendage, pa...

Moguls of the heart

The 'moguls of the heart' refer to the bulges of the cardiomediastinal contour on frontal chest radiographs. The cardiomediastinal bulges are likened to skiing moguls (bumps of packed snow on a mountainside sculptured by turning skis). Awareness of their usual locations and etiologies is helpful...

Bouchard node

Bouchard nodes are a clinical sign relating to bony nodules of the proximal interphalangeal joints and are much less common than Heberden nodes. They generally (but not always) correspond to palpable osteophytes. Clinical presentation They are sometimes painful, and are typically associated wi...

Box-shaped heart

A box-shaped heart is a radiographic description given to the cardiac silhouette in some cases of Ebstein anomaly. The classic appearance of this finding is caused by the combination of the following features: huge right atrium that may fill the entire right hemithorax shelved appearance of th...

Honda sign (sacrum)

The Honda sign (H sign / H pattern) is a term used to describe the appearance of bilateral sacral insufficiency fractures on a radioisotope bone scan. Radiographic features Sacral insufficiency fractures are usually vertically through the sacral alae, paralleling the sacroiliac joint, often wi...

Target sign (tuberculosis)

The target sign of tuberculosis refers to the bull's eye appearance of some parenchymal tuberculomas involving the brain (see: CNS tuberculosis) and solid abdominal organs (see: hepatic and splenic tuberculosis) on cross-sectional imaging. Radiographic features Ultrasound hypoechoic nodules ...

Curlicue ureter sign (sciatic hernia)

The curlicue ureter sign1 was described on intravenous pyelogram studies in cases of ureteral herniation into a sciatic hernia, causing a curled appearance of the herniated ureter. Although very rare, this sign is pathognomonic of sciatic hernia. It can also be seen on CT urogram studies.

Bridging vessel sign

The bridging vessel sign refers to an appearance of vessels coursing from the uterus into an adjoining pelvic mass (a vascular bridge). This sign helps to differentiate a pedunculated subserosal uterine leiomyoma from other juxtauterine masses of ovarian, adnexal or bowel origin. Color and powe...

Ring shadow (disambiguation)

Ring shadows are radiographic signs seen on either chest x-rays or on upper gastrointestinal fluoroscopy: ring shadow (chest) ring shadow (abdomen)

Blend sign (brain)

The blend sign refers to the appearance of intracranial hematoma in non-contrast CT brain. It is a strong predictor of early hematoma expansion in spontaneous intracerebral hemorrhages, which is a prognosticator for poor functional outcomes 1. The blend sign is defined as 2: blending of a rela...

Marcus Gunn pupil

A Marcus Gunn pupil, also known as a relative afferent pupillary defect (RAPD), is a non-specific sign on physical examination that indicates partial optic nerve dysfunction. It is mainly due to unilateral optic neuropathy (e.g. optic neuritis), or rarely optic chiasm or optic tract lesions. Th...

Macaroni sign (arteries)

The macaroni sign is a sign seen in Takayasu arteritis on ultrasound. It represents the smooth, homogeneous and moderately echogenic circumferential thickening of the arterial wall that occurs in Takayasu arteritis. The sign is highly specific for Takayasu arteritis, more commonly noted in the ...

Tensile gallbladder fundus sign

The tensile gallbladder fundus sign is positive when the gallbladder fundus is seen to bulge into, and distort, the anterior abdominal wall and is a feature of acute cholecystitis. It is particularly useful as an early sign of the condition on CT as it has around a 75% sensitivity and 95% speci...

Spoke wheel sign (meningioma)

The spoke wheel sign refers to the pattern of vessels coursing through meningiomas, when seen in cross-section. It is the result of the same phenomenon which results in the sunburst pattern (vessels seen from the side rather than in cross-section). Terminology A similar appearance also referr...

Butterfly sign (choroid plexus)

The butterfly sign refers to the normal appearance of the choroid plexuses on axial imaging of the fetal brain, commonly observed on the antenatal ultrasound. Its absence may suggest holoprosencephaly 1. In the CNS, the term should not be confused with a butterfly glioma, which is a glioblastom...

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