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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

860 results found
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60/60 sign (echocardiography)

The 60/60 sign in echocardiography refers to the coexistence of a truncated right ventricular outflow tract acceleration time (AT <60 ms) with a pulmonary arterial systolic pressure (PASP) of less than 60 mmHg (but more than 30 mmHg). In the presence of right ventricular failure, it is consisten...
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Abnormal bowel wall attenuation patterns

Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories: white enhancement gray enhancement water halo sign fat halo sign black attenuation The first three patterns are seen on contrast studies. White enhancement It is defined as uniform enhancement of th...
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Abnormally eccentric gestational sac

An eccentrically-located gestational sac towards the fundus of the uterus is the normal sonographic appearance; however an abnormally eccentric gestational sac on ultrasound may be apparent due to a number of causes They include interstitial ectopic pregnancy 1 normally implanted pregnancy in...
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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 bow-tie-shaped structures between the femoral condyles and tibial plateaux. As the no...
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Absent nasal bone

In a fetal sonographic assessment, an absent nasal bone is a feature which can sometimes be used as a surrogate marker for fetal aneuploidy. Radiographic assessment Antenatal ultrasound It is assessed on a midline sagittal view. In this section, the nasal bone is often seen as a bright echoge...
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Accordion sign (colon)

The accordion sign (also known as concertina sign) is seen on CT examinations of the abdomen and refers to the similarity between the thickened edematous wall of pseudomembranous colitis and the folds of an accordion. This appearance is the result of hyperemic enhancing mucosa stretched over mar...
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Ace-of-spades sign (heart)

Ace-of-spades sign refers to the pathognomonic configuration of the left ventricle as seen in apical hypertrophic cardiomyopathy 1-3. It consists of marked ventricular wall thickening at the apex resulting in cavity narrowing at the apex with a relatively normal appearance of the mid-ventricula...
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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...
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Air bronchogram

Air bronchogram refers to the phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than air fills the alveoli. Air bronchograms will not ...
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Air bubble sign (tension pneumocephalus)

The air bubble sign is seen on CT of the brain and represents multiple small foci of air within the subarachnoid space, especially the Sylvian fissure.1 Although described as a sign of tension pneumocephalus it is also seen in pneumocephalus without elevated pressures.2 It should not be confus...
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Air crescent sign (lung)

An air crescent sign describes the crescent of air that can be seen in invasive aspergillosis, semi-invasive aspergillosis or other processes that cause pulmonary necrosis. It usually heralds recovery and is the result of increased granulocyte activity. In angioinvasive fungal infection, the no...
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Air trapping

Air trapping in chest imaging refers to retention of excess gas (“air”) in all or part of the lung, especially during expiration, either as a result of complete or partial airway obstruction or as a result of local abnormalities in pulmonary compliance. It may also sometimes be observed in norma...
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A-line (ultrasound)

An a-line is an ultrasonographic artifact appreciated during insonation of an aerated lung. 1 The term may be applied to the horizontal, echogenic long path reverberation artifacts that occur beneath the pleural line at multiples of the distance between the ultrasound probe and the visceral-par...
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Andersson lesion

Andersson lesions refer to an inflammatory involvement of the intervertebral discs by spondyloarthritis. Epidemiology Rheumatic spondylodiskitis is a non-infectious condition that has been shown to occur in about 8% of patients with ankylosing spondylitis, as detected at radiography. Patholog...
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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...
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Animal and animal produce inspired signs

Animal and animal produce inspired signs may sound a little silly, but the radiology literature is replete with such signs, some more fanciful than others. Fish and seafood cluster of black pearls sign endosteal scalloping: medullary cavity masses, e.g. multiple myeloma fish vertebra (also k...
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Aniridia

Aniridia refers to either the clinical sign of a complete/partial absence of the iris, or more specifically to the disease entity classic aniridia. Rarely other genetic conditions may cause this sign. Epidemiology Classic aniridia is inherited as an autosomal dominant condition and is seen in ...
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Anisocoria

Anisocoria is present when an individual's pupils differ in size. If a person's pupils are symmetric there is said to be isocoria. Epidemiology The prevalence of transient physiological anisocoria of >0.4 mm is found in up to 20% population. However persistent anisocoria seems to be rarer, in ...
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Anteater nose sign (foot)

The anteater nose sign refers to an anterior tubular elongation of the superior calcaneus which approaches or overlaps the navicular on a lateral radiograph of the foot. This fancifully resembles the nose of an anteater and is indicative of calcaneonavicular coalition 1,2.  History and etymolog...
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Anterior bronchus sign

The anterior bronchus sign refers to the appearance of the anterior segmental bronchus of the upper lobes as seen on a frontal chest radiograph. Gross anatomy The anterior segment bronchus of the upper lobes courses anteriorly and laterally. When the orientation is predominantly anteriorly the...
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Anterior tibial translocation sign

The anterior tibial translocation sign or anterior drawer sign (a.k.a. anterior translation of tibia) is seen in cases of complete rupture of the anterior cruciate ligament, and refers to anterior translocation (anterior tibial subluxation) of the tibia relative to the femur of >7 mm 1. 
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Antler sign (lung)

The antler sign is an uncommon sign of lung torsion on CT where branches from the main pulmonary artery all arise from a single side, indicating twisting of the lobe or lung. In the normal lung, the main pulmonary arteries are straight and lobar and segmental branches arise from it on both side...
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Antral nipple sign

The antral nipple sign refers to redundant pyloric mucosa protruding into the gastric antrum and is seen in pyloric stenosis. See also cervix sign of pyloric stenosis target sign of pyloric stenosis shoulder sign of pyloric stenosis
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Antral pad sign

The antral pad sign is a feature seen on a spot radiograph of the upper gastrointestinal tract obtained with orally-administered contrast material. It refers to the extrinsic impression or indentation on the posteroinferior aspect of the antrum. The impression is generally arcuate and smooth, an...
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Apple core sign (colon)

The apple core sign, also known as the napkin ring sign (bowel), is most frequently associated with constriction of the lumen of the colon by a stenosing annular colorectal carcinoma. Differential diagnosis The appearance of the apple-core lesion of the colon also can be caused by other diseas...
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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 has also been observed with: pigmented villonodular synovitis ...
Article

Apple-peel intestinal atresia

Apple-peel intestinal atresia, also known as type IIIb or Christmas tree intestinal atresia, is a rare form of small bowel atresia in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply in a spiral resembling an apple peel. Oft...
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Arc sign (CARASIL)

The arc sign has been described in late-stage CARASIL and is seen on axial T2 weighted images. It describes high signal extending from one middle cerebellar peduncle, across the pons, to the contralateral middle cerebellar peduncle 1. 
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Arcuate sign (knee)

The arcuate sign is often a subtle but important finding on knee x-rays and represents an avulsion fracture of the proximal fibula at the site of insertion of the arcuate ligament complex, and is usually associated with cruciate ligament injury (~90% of cases) 2. The fracture fragment is attache...
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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 ...
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Arrowhead sign (cecum)

The arrowhead sign refers to the focal cecal thickening centered on the appendiceal orifice, seen as a secondary sign in acute appendicitis. The contrast material in the cecal lumen assumes an arrowhead configuration, pointing at the appendix.   The arrowhead sign is applicable only when enteri...
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Atoll sign (disambiguation)

The atoll sign in radiology can refer to: reverse halo sign: atoll sign in thoracic CT atoll sign in liver MRI: suggestive of an inflammatory hepatic adenoma
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Atoll sign (liver MRI)

The atoll sign in hepatic imaging has been described when a liver lesion shows a peripheral rim of high T2 signal intensity with the center of the lesion appearing isointense to the background of non-cirrhotic liver on T2WI mimicking an atoll. It is considered a characteristic sign of an inflamm...
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Atrial escape

Atrial escape refers to a chest x-ray sign of massive left atrial enlargement and is an exaggerated version of the double density sign.   Normally, the right border of the left atrium is not visible. As it enlarges it forms a distinct border projecting through the right heart shadow, medial to ...
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Aubergine sign (penis)

The aubergine sign (also known as egg-plant sign or deformity) is a clinical sign of a fractured penis. Hemorrhage beyond the tunica albuginea produces swelling and bruising of the penis simulating the appearance of an aubergine.  
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Baastrup syndrome

Baastrup syndrome (also referred to as kissing spines) results from adjacent spinous processes in the lumbar spine rubbing against each other and resulting in hypertrophy and sclerosis with focal midline pain and tenderness relieved by flexion and aggravated by extension.  Epidemiology It tend...
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Backwash ileitis

Backwash ileitis is seen in patients with ulcerative colitis (UC), where the entire colon is involved. In such cases the terminal ileum is edematous. Backwash ileitis extends contiguously backward from the cecum without skip regions. One source estimates it to occur in 6% of patients with UC, a...
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Ballet sign (eyeball)

The ballet sign refers to the paralysis of voluntary movements of the eyeball with preservation of the automatic movements. Sometimes this sign is present with exophthalmic goiter and hysteria.
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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...
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Balloon on a string sign (ureter)

The balloon on a string sign refers to the appearance of the ureter on intravenous urography in ureteropelvic junction obstruction. It is seen due to the high and eccentric point of the exit of ureter from a dilated renal pelvis. 
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Bamboo spine (ankylosing spondylitis)

Bamboo spine is a radiographic feature seen in ankylosing spondylitis that occurs as a result of vertebral body fusion by marginal syndesmophytes. It is often accompanied by fusion of the posterior vertebral elements as well.  A bamboo spine typically involves the thoracolumbar and/or lumbosacr...
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Banana sign (cerebellum)

The banana sign is one of the many notable fruit inspired signs. This sign is seen on axial imaging through the posterior fossa of fetuses with associated conditions such as  Chiari II malformation and/or spina bifida. In Chiari II malformation, the banana sign describes the way the cerebellum...
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Barbell sign (progressive multifocal leukoencephalopathy)

The barbell sign has been described in a short series of patients with progressive multifocal leukoencephalopathy (PML) 1. This describes confluent FLAIR / T2w parieto-occipital abnormalities with a thin continuation of signal abnormality across the splenium. Given the lack of mass effect typi...
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Bare orbit sign (sphenoid wing)

The bare orbit sign, is described as a characteristic appearance of the orbit, seen when the innominate line is absent. The innominate line is a projection of the greater wing of the sphenoid, and its absence or destruction is responsible for this appearance. It is the classical frontal radiogr...
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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...
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Bat wing 4th ventricle

Bat wing 4th ventricle sign refers to the morphology of the fourth ventricle in the Joubert anomaly and related syndromes. The absence of a vermis with apposed cerebellar hemispheres give the fourth ventricle an appearance reminiscent of a bat with its wings outstretched. It is best demonstrate...
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Bat wing opacities (lungs)

Bat's wing or butterfly pulmonary opacities refer to a pattern of bilateral perihilar shadowing. It is classically described on a frontal chest radiograph but can also refer to appearances on chest CT 3-4. Differential diagnosis Bat's wing pulmonary opacities can be caused by: pulmonary edema...
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Bayonet deformity (wrist)

Bayonet deformity is a term used to describe the shape of the wrist in certain conditions: Madelung deformity hereditary multiple exostosis with pseudo-Madelung deformity retarded bone growth of the distal ulna with outward bowing of the radius with distal radioulnar joint subluxation Colles...
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Beads on a string sign (chronic salpingitis)

The beads-on-a-string sign is used to refer to the classic morphologic changes in the Fallopian tubes as a result of chronic salpingitis.    Terminology The "string" alludes to the notably thin salpingeal wall, while the hyperechoic mural nodules constitute the "beads" 1. Radiographic feature...
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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 wh...
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Beak sign (pyloric stenosis)

Beak sign in pyloric stenosis is one of the fluoroscopic (barium meal) findings which is useful in the diagnosis of congenital hypertrophic pyloric stenosis.  Radiographic features Barium meal A beak-like tapering projection of barium is seen entering into the narrowed and compressed pyloric ...
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Bear paw sign (kidney)

The bear paw sign is seen in xanthogranulomatous pyelonephritis and refers to the cross-sectional appearance of the kidney which is said to resemble the paw of a bear. The renal pelvis is contracted whereas the calyces are dilated, mimicking the toe-pads of the paw.
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Beck triad

Beck triad is a collection of three clinical signs associated with pericardial tamponade which is due to an excessive accumulation of fluid within the pericardial sac. The three signs are: low blood pressure (weak pulse or narrow pulse pressure) muffled heart sounds  raised jugular venous pre...
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Bifid postcentral gyrus sign

The bifid postcentral gyrus sign, also known as the pars deflection sign, is a landmark useful for identifying the central sulcus on cross-sectional imaging. The medial aspect of the postcentral gyrus splits in two before meeting the interhemispheric fissure. The two legs straddle the pars marg...
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Big rib sign

The big rib sign is a sign to differentiate right and left ribs on lateral chest radiographs.  It exploits a technique of magnification differences on lateral projections between right and left ribs. For example, on right lateral projections the left ribs appear larger than right ribs.  This s...
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Bilateral adrenal gland hyperenhancement

Bilateral adrenal gland hyperenhancement or intense adrenal enhancement may be a feature of hypotension and forms part of the CT hypoperfusion complex. Adrenal gland hyperenhancement has been described in pediatric and small adult series or individual cases of hemorrhagic shock, pancreatitis, s...
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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...
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Bird beak sign (esophagus)

The bird's beak sign of the esophagus is used to refer to the tapering of the inferior esophagus in achalasia. The same appearance (although it is difficult to see the similarity) is also referred to as the rat-tail sign. The appearance, although classically occurring in primary achalasia, can ...
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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...
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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 ...
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Black turbinate sign (nasal cavity)

The black turbinate sign refers to an area of non-enhancing mucosa on MRI in a patient with angioinvasive fungal sinus infection / rhinocerebral mucormycosis. Mucormycosis is caused by fungi that include Mucor, Rhizopus, and Absidia species.  It is seen in diabetic and immunocompromised patient...
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Blade of grass sign (Paget disease)

The blade of grass sign, also called the candle flame sign, refers to the lucent leading edge in a long bone seen during the lytic phase of Paget disease of bone.  The blade of grass sign is characteristic of Paget disease of bone. This is akin to osteoporosis circumscripta cranii seen in the s...
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Blend sign (brain)

The blend sign refers to a CT appearance of early intracranial hematoma growth. It is defined as blending of a hypoattenuating area and a hyperattenuating region with a well-defined margin.
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B-line (ultrasound)

The B-line is an artifact relevant in lung ultrasonography. As originally described, it has seven defining features 1: a hydroaeric comet-tail artifact arising from the pleural line hyperechoic well-defined extending indefinitely erasing A-lines  moving in concert with lung sliding, if lung...
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Bone within a bone appearance

Bone within a bone is a descriptive term applied to bones that appear to have another bone within them. There are numerous causes including: normal thoracic and lumbar vertebrae (neonates and infants) growth recovery lines (after infancy) cortical splitting and new periostitis sickle cell d...
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Boomerang sign (disambiguation)

Boomerang sign may refer to: boomerang sign (peroneus brevis tear) boomerang sign (medial meniscal tear) boomerang sign (splenium) History and etymology Boomerang is of course a curved projectile used originally by the Australian Aborigines, one of its various uses was as a hunting weapon 1.
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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...
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Boomerang sign (splenium)

The boomerang sign refers to a boomerang-shaped region of cytotoxic edema in the splenium of the corpus callosum typically seen in cytotoxic lesions of the corpus callosum (CLOCCs) 1-4.  See also boomerang sign in peroneus brevis split syndrome boomerang sign in horizontal meniscal flap tear
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Bouchard node

Bouchard nodes are a clinical sign relating to bony nodules of the 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 associat...
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Bouquet of flowers appearance (medullary sponge kidney)

A bouquet of flowers appearance is a description given to the appearances of medullary sponge kidney on a traditional intravenous pyelogram (IVP) study. The ectatic distal collecting ducts contain the microcalcifications typical of the disease. This is also known as the bunch of grapes appearanc...
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Boutonniere deformity

Boutonniere deformity is one of the musculoskeletal manifestations of rheumatoid arthritis in the hand with: flexion contracture of the proximal interphalangeal (PIP) joints extension of the distal interphalangeal (DIP) joints  The defect appears in the tendon which splays open. The appearanc...
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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...
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Brachytherapy seed migration to the lung

Brachytherapy seed migration to the lung is a known complication of radioactive seed therapy. These seeds are used for localized treatment of malignancies, most commonly prostate cancer. Regarding staging, nearly 79% of the cases are localized, 12% are regional and 5% present with distant disea...
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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...
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Bracket sign (pericallosal lipoma)

The bracket sign refers to a radiographic appearance seen with the tubulonodular variety of pericallosal lipoma. It reflects calcification seen at the periphery of the midline lipoma. It is best seen on coronal imaging and historically was identified on frontal radiographs. It should not be con...
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Breast within a breast sign

The breast within a breast sign refers to the common mammographic appearance of breast hamartomas (fibroadenolipomas). Since these benign lesions are well-circumscribed and contain a mixture of fibrous, glandular and fatty tissue (just like normal breast), it is not surprising that they appear v...
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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...
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Bright dot sign (atypical liver hemangioma)

The bright dot sign refers to the presence of a bright dot within a lesion which remains hyperattenuating on arterial and portal venous phase CT, corresponding to early nodular enhancement seen on dynamic MRI of liver hemangioma.  This can be used as an indicator that the lesion in question is ...
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Bright rim sign (anterior talofibular ligament injury)

The bright rim sign in anterior talofibular ligament injury refers to a sign seen on MRI. A cortical defect with a bright dot-like or curvilinear high-signal-intensity, usually at the fibular attachment site, is seen on MRI. It has been described as an indicator of ATFL injury 1. See also brig...
Article

Bright rim sign (disambiguation)

The bright rim sign in MRI can refer to  bright rim sign in DNETs bright rim sign in ATFL injury 1 putaminal rim sign
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Bright rim sign (DNET)

The bright rim sign, also known as the hyperintense ring sign, has been described in dysembryoplastic neuroepithelial tumors (DNET). It is described as a well defined rim of high signal around the DNET on FLAIR sequences. This T2/FLAIR hyperintense ring, whether complete or in complete, is fair...
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Broken heart sign

The broken heart sign 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 the short process of the incus relative to the head of the malleus 1,2.
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Bronchial cut-off sign

The bronchial cut-off sign refers to the abrupt truncation of a bronchus from obstruction, which may be due to cancer, mucus plugging, trauma or foreign bodies. Typically, there is associated distal lobar collapse. 
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Bronchorrhea

Bronchorrhea is the expectoration of copious amounts of mucus from the lungs. It has been defined as production of more than 100 mL of mucus in 24 hours, which is more than is usually seen in chronic lung disease (e.g. chronic bronchitis typically produces 25 mL/24 hrs) 2. It may be a feature of...
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Brudzinski sign (meningism)

Brudzinski's sign occurs in meningitis (of any etiology) or meningism where passive flexion of a patient's neck elicits reflexive bilateral knee and hip flexion; it was originally known as the "nape of the neck sign" and was one of several physical exam maneuvers concurrently described to be cha...
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Bubbly consolidation

Bubbly consolidation describes internal or central lucencies which represent normal aerated lung lobule within infarcted, consolidated, lung parenchyma. It is one of the highly specific imaging appearances of focal pulmonary hemorrhage or possibly pulmonary infarct secondary to pulmonary embolis...
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Bulging fissure sign (lobar consolidation)

The bulging fissure sign refers to lobar consolidation where the affected portion of the lung is expanded causing displacement of the adjacent fissure. Any type of pneumonia or space-occupying process can lead to bulging (sagging) fissure sign. Classically, it has been described in right upper l...
Article

Bullet and bodkin sign

Bullet and bodkin sign is the appearance of the ureter when there is an abrupt transition in the ureteral caliber. Bullet in the name is represented by the dilated proximal ureteric segment which appears to be perched on the constricted / non-dilated encased ureter which gives an appearance of a...
Article

Bullet-shaped vertebra

Bullet-shaped vertebra refers to the anterior beaking of the vertebral body. It is seen in the following conditions: mucopolysaccharidosis (Morquio disease, Hurler disease) achondroplasia congenital hypothyroidism  See also weapons and munitions inspired signs
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Bunch of grapes sign (disambiguation)

Bunch of grapes sign refers to the ultrasound appearance of multiple cystic spaces or lesions and it has been described in a number of settings: within the uterus as a result of hydropic swelling of trophoblastic villi within a hydatidiform mole in bronchiectasis, where on a chest radiograph, ...
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Bunny waveform sign

Bunny waveform sign refers to the morphology of the spectral waveform in the vertebral artery in early subclavian steal syndrome 1-3.
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Burst lobe

A burst lobe is an uncommonly used description of traumatic lobar intraparenchymal hemorrhage of the brain that ruptures into the subdural space and communicates with subdural hemorrhage 1. As traumatic hemorrhages are more common in the frontal and temporal lobes, these lobes are the most affe...
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Butterfly glioma

Butterfly gliomas are a high grade astrocytoma, usually a glioblastoma (WHO grade IV), which crosses the midline via the corpus callosum. Other white matter commissures are also occasionally involved. The term butterfly refers to the symmetric wing-like extensions across the midline.  Most freq...

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