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.

47 results found
Article

Anteater nose sign

The anteater nose sign refers to an anterior tubular prolongation 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 an indication of calcaneonavicular coalition 1-2.  History and ety...
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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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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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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 (in infants) growth recovery lines (after infancy) sickle cell disease / thalassaemia autosomal dominant osteopet...
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Bracket sign

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.
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Butterfly vertebra

Butterfly vertebra is a type of vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochordal tissue between them. Pathology Associations an anterior spina bifida, with or without an anterior meninogocoele can be part ...
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Cervix sign of pyloric stenosis

The cervix sign of pyloric stenosis describes indentation of the pylorus into the fluid-filled antrum, seen in pyloric stenosis. See also antral nipple sign target sign of pyloric stenosis shoulder sign of pyloric stenosis
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Copper beaten skull

Copper beaten skull, also known as beaten brass skull, refers to the prominence of convolutional markings (gyral impressions on the inner table of the skull) seen throughout the skull vault. Demographics and clinical presentation The appearance of copper beaten skull is associated with raised ...
Article

Corkscrew sign

The corkscrew sign describes the spiral appearance of the distal duodenum and proximal jejunum seen in midgut volvulus. It has been identified as a diagnostic indicator of midgut volvulus1. In patients with malrotation and volvulus, the distal duodenum and proximal jejunum do not cross the midl...
Article

Coxa valga

Coxa valga describes a deformity of the hip where there is increased angle between the femoral neck and femoral shaft.  Pathology Coxa valga is often associated with shallow acetabular angles and femoral head subluxation.  Aetiology bilateral neuromuscular disorders, e.g. cerebral palsy of...
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Crescent in a doughnut sign

The crescent in a doughnut sign refers to the transverse ultrasound appearance of intestinal intussusception, and is a variation of the target sign (which is also known as the doughnut sign) The doughnut is formed by concentric alternating echogenic and hypoechogenic bands. The echogenic b...
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Double bubble sign

The double bubble sign is seen in infants and represents dilatation of the proximal duodenum and stomach. It is seen in both radiographs and ultrasound, and can be identified antenatally 2. Pathology Causes include 1,2: congenital obstruction duodenal web duodenal atresia duodenal stenosis...
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Double density sign of osteoid osteoma

The double density sign, also sometimes clumsily referred to as the hotter spot within hot area sign, is a bone scan sign of an osteoid osteoma. It refers to a central focus of intense uptake (the nidus) within a surrounding lower, but nonetheless increased uptake, rim. See also double densit...
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Double track sign of pyloric stenosis

The double track sign is a radiological sign described in pyloric stenosis on various imaging modalities.  Barium study Double streaks of barium passing through the narrow pylorus.1 Ultrasound On fluid aided real-time examination, Pyloric fluid compressed into smaller tracks as it is impinge...
Article

Echogenic fetal bowel

Echogenic fetal bowel is an observation in antenatal ultrasound imaging, in which fetal bowel appears to be brighter than it is supposed to be. It is a soft marker for trisomy 21 and has several other associations. When observed, it needs to be interpreted in the context of other associated abno...
Article

Egg-on-a-string sign

Egg-on-a-string sign, also referred as egg on its side, refers to the cardiomediastinal silhouette seen in transposition of the great arteries (TGA). The heart appears globular due to an abnormal convexity of the right atrial border and left atrial enlargement and therefore appears like an egg...
Article

Flat floor of fourth ventricle sign

The flat floor of fourth ventricle sign is useful in detecting a pontine mass and is a sign of mass effect. The normal floor of the fourth ventricle (remember that the floor is anterior) normally slopes upwards towards the midline, with the facial colliculi visible on either side.  It is a non-...
Article

Gage sign

Gage sign is a V-shaped lucent defect at the lateral portion of the epiphysis and/or adjacent metaphysis. It is pathognomonic to 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 lateral t...
Article

Harlequin eye deformity

The harlequin eye deformity may seen in unilateral (plagiocephaly) or bilateral (brachycephaly) coronal suture synostosis, and refers to the elevation of the superolateral corner of the orbit.
Article

Harrison's sulcus

Harrison's sulcus refers to a groove at the lower end of the rib cage seen in young children / infants with abnormally weak bones (e.g. rickets) or chronic respiratory disease (e.g. severe asthma). The lower chest is drawn in with flaring of the rib margin. The exact cause is controversial altho...
Article

Haystack sign

The haystack sign on chest x-rays in paediatric patients is indicative of pneumomediastinum. The paediatric heart is surrounded above and below with air and giving it an appearance of a haystack from Monet's paintings. 
Article

J shaped sella

A J-shaped sella is a variant configuration of the sella turcica, where the tuberculum sellae is flattened, thus forming the straight edge of the "J". The dorsum sellae remains rounded and forms the loop of the "J". Differential diagnosis Differential diagnosis for a J-shap...
Article

Keyhole sign

The keyhole sign is an ultrasonographic sign seen in boys with posterior urethral valves. It refers to the appearance of posterior urethra which is dilated, and associated thick walled distended bladder which on ultrasound may resemble a key hole.
Article

Kirner deformity

Kirner deformity is characterised by a curvature of the distal phalynx of the 5th digit in both a palmar and radial direction. Epidemiology The deformity typically presents in late childhood to early adolescence, although a mild deformity may be present at birth. Both sexes are affected, altho...
Article

Medial stripe sign

Medial stripe sign refers to an area of increased lucency at the interface of the medial lung and the mediastinum in case of medial pneumothorax. A small volume of pneumothorax generally accumulates anteriorly or medially which can be difficult to detect hence this sign holds a certain significa...
Article

Mushroom sign of pyloric stenosis

The mushroom sign (also called umbrella sign) is a radiological sign described in pyloric stenosis on barium examination. This sign refers to the impression made by the hypertrophic pylorus on the duodenal cap. See also shoulder sign cervix sign of pyloric stenosis target sign of pyloric st...
Article

Neuhauser sign

Neuhauser sign refers to a soap bubble appearance seen in the distal ileum in cases of meconium ileus, related to the air mixed with meconium. It may be seen with barium enema if contrast passes beyond the ileocaecal valve or with small-bowel follow-through. Although classically described with ...
Article

Non-accidental injuries

Non-accidental injuries (NAI) represent both ethical and legal challenges to treating physicians. Radiologists are often the first to suspect NAI when confronted with particular injury patterns, and a knowledge of these is essential if the opportunity to save a child from future neglect is not ...
Article

Omega sign

The omega sign refers to the thickened aryepiglottic folds and epiglottis seen in epiglottitis, when the larynx is seen endoscopically or via laryngoscope, and not to the appearance on lateral plain films. CT would show the finding, but placing a child with epiglottitis supine to CT their neck i...
Article

Pseudokidney of intussusception

The pseudokidney of intussusception refers to the longitudinal ultrasound appearance of the intussuscepted segment of bowel. The fat containing mesentary which is dragged into the intussusception, containing vessels, is reminiscent of the renal hilum, with the renal parenchyma formed by the oe...
Article

Pulmonary plethora

Pulmonary plethora is a term used to describe the appearances of increased pulmonary perfusion on chest radiographs. It is commonly used in paediatric radiology.  Pathology Usually a left-to-right shunt of 2:1 is required for pulmonary plethora to occur 2,3. Increased pulmonary perfusion occur...
Article

Rachitic rosary

Rachitic rosary refers to expansion of the anterior rib ends at the costochondral junctions and is most frequently seen in rickets as nodularity at the costochondral junctions. Differential diagnosis Other causes of this appearance include:  scurvy:  the costochondral junction is more angula...
Article

Radiocapitellar line

The radiocapitellar line is one of the key lines used to assess alignment on the elbow radiograph. It is particularly useful in the paediatric setting. The rule A line drawn down the neck of the radius should intersect the capitellum. It is important to ensure that you draw the line down the r...
Article

Shoulder sign of pyloric stenosis

The shoulder sign of pyloric stenosis is seen during barium examination and refers to the bulging of the hypertrophied pyloric muscle into the lumen of the antrum. It is closely related to the cervix sign of pyloric stenosis.  See also cervix sign of pyloric stenosis target sign of pyloric ...
Article

Snowman sign: total anomalous pulmonary venous return

Snowman sign refers to the configuration of the heart and the superior mediastinal borders resembling a snowman. This is seen in total anomalous pulmonary venous return (TAPVR) type I (supracardiac type). It is an abnormality of the fetal circulation wherein the entire pulmonary venous flow is ...
Article

Steeple sign

The steeple sign, also called wine bottle sign, refers to the tapering of the upper trachea on a frontal chest radiograph reminiscent of a church steeple. The appearance is suggestive of croup, which should be obvious clinically. A corresponding lateral x-ray would show narrowing of the subglott...
Article

Strawberry skull

Strawberry skull refers to the shape of the head on an antenatal ultrasound. Epidemiology Associations In general, strawberry skull is considered one of the nonspecific 'soft markers' for abnormal fetal development. It is considered more closely associated with trisomy 18 (Edward syndrome). ...
Article

Target sign of intussusception

There are many target signs, one of which the the appearance of intestinal intussusception, also known as the doughnut sign. The appearance is generated by concentric alternating echogenic and hypoechogenic bands. The echogenic bands are formed by mucosa and muscularis whereas the submucosa is ...
Article

Target sign of pyloric stenosis

The target sign of pyloric stenosis is a sign seen due to hypertrophied hypoechoic muscle surrounding echogenic mucosa, seen in pyloric stenosis. This is likened to that of a target. See also antral nipple sign cervix sign of pyloric stenosis shoulder sign of pyloric stenosis
Article

Tectal beaking

Tectal beaking refers to fusion of midbrain colliculi into a single beak pointing posteriorly and invaginating into cerebellum. It is seen with a Chiari type II malformation.
Article

Thumb sign of epiglottitis

The thumb sign is a manifestation of an oedematous 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.  Terminology Thumb sign is a term also...
Article

Thymic notch sign

The thymic notch sign represents normal thymus in newborn on a frontal chest radiograph. Interruption of the cardiac silhouette forms a notch, which may be seen on either side, but more frequently seen on left side. 
Article

Thymic sail sign

The thymic sail sign represents a triangular-shaped inferior margin of the normal thymus seen on neonatal frontal chest radiograph. It is more commonly seen on the right side, and can also be bilateral. It is seen in 3-15% of all cases. This sign should not be confused with the spinnaker sail si...
Article

Triangular cord sign

The triangular cord sign is a triangular or tubular echogenic cord of fibrous tissue seen in the porta hepatis at ultrasonography and is relatively specific in the diagnosis of  biliary atresia1,2. This sign is useful in the evaluation of infants with cholestatic jaundice, helping for the diffe...
Article

Wimberger ring sign

Wimberger ring sign refers to a circular calcification surrounding the osteoporotic epiphyseal center of ossification in scurvy, which may result from bleeding. It must not be confused with Wimberger sign, pathognomonic of congenital syphilis.
Article

Wimberger sign

The Wimberger sign, also called Wimberger corner sign, refers to localised bilateral metaphyseal destruction of the medial proximal tibias. It is a pathognomonic sign for congenital syphilis. It must not be confused with Wimberger ring sign seen in scurvy, which is sometimes also referred to as...
Article

Zebra stripe sign

The zebra stripe sign occurs where children with osteogenesis imperfecta have been treated with cyclical bisphosphonate therapy, e.g. pamidronate. When the drug is delivered in cycles, dense bone is formed while treatment is being given. This results in dense stripes across the metaphyses of bon...

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