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.

729 results found
Article

Cervicothoracic sign

The cervicothoracic sign, a variation of the silhouette sign, helps to localize a mass in the superior mediastinum on frontal chest radiographs as either anterior or posterior.  As the anterior mediastinum ends at the level of the clavicles, the upper border of an anterior mediastinal lesion ca...
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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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Champagne glass pelvis (achondroplasia)

The champagne glass pelvis is a helpful sign in achondroplasia in which the iliac blades are flattened, giving rise to a pelvic inlet that resembles a champagne glass. The acetabular angles are flattened (horizontal) and the sacrosciatic notch is small.
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Chang sign (pulmonary embolism)

The Chang sign refers to the dilatation and abrupt change in calibre of the main pulmonary artery due to pulmonary embolism 1.  History and etymology It is named after C. H. Joseph Chang, (July 7 1929 - November 15 2017) an American radiologist, who first described it in 1965 2. See also knu...
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Chasing the dragon sign (toxic leukoencephalopathy)

Chasing the dragon sign is seen in toxic leukoencephalopathy caused by the inhalation of heroin fumes.  Clinical presentation Three stages are recognised: cerebellar signs and motor restlessness pyramidal and pseudobulbar signs spasms, hypotonic paresis, and ultimately death Only a minorit...
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Cheerio sign (pulmonary nodule)

Cheerio sign in thoracic imaging relates to pulmonary nodules with a central lucent cavity as seen on CT. It is due to proliferation of (malignant or non-malignant) cells around an airway. They are so named because of their resemblance to the breakfast cereal, Cheerios 1-2.  The Cheerio sign (p...
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Cheerio sign (shoulder)

The Cheerio sign has been described as a sign seen in a type III superior labral anterior posterior tear (SLAP lesion) of the glenoid labrum. In the cheerio sign, a rounded core of soft tissue is surrounded by a rim of contrast material and gas.  SLAP type III is the bucket handle tear of the s...
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Chorionic bump

Chorionic bump is a finding that can be uncommonly seen in a first-trimester scan. It may represent a small haematoma bulging into the gestational sac or an anembryonic (failed) second pregnancy that is being resorbed. It is also seen in some patients undergoing infertility treatment. Epidemiol...
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Cingulate sulcus sign

The cingulate sulcus sign has been proposed as being useful as an MRI feature of idiopathic normal pressure hydrocephalus (NPH). It denotes the posterior part of the cingulate sulcus being narrower than the anterior part. The divider between the anterior and posterior parts of the sulcus being a...
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Claw sign (mass)

The claw sign is useful in determining whether a mass arises from a solid structure or is located adjacent to it and distorts the outline. It refers to the sharp angles on either side of the mass, which the surrounding normal parenchyma forms when the mass has arisen from the parenchyma. As suc...
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Cloaca (osteomyelitis)

A cloaca (pl. cloacae/cloacas) can be found in chronic osteomyelitis. The cloaca is an opening in an involucrum which allows drainage of purulent and necrotic material out of the dead bone. If the tract extends to the skin surface, the portion extending beyond the involucrum to the skin surface...
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Cloverleaf skull

Cloverleaf skull, also known as kleeblattschädel, refers to a type of severe craniosynostosis which gives the skull a cloverleaf shape. It is very rare, with less than 130 case reports globally. It typically results from intrauterine premature closure of the sagittal, coronal and lambdoid suture...
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Cobblestone appearance (hollow viscera)

Cobblestoning (having a cobblestone appearance) can occur in a number of hollow organs with mucosa, most commonly the bowel, in the setting of Crohn disease.  Longitudinal and circumferential fissures and ulcers separate islands of mucosa, giving it an appearance reminiscent of cobblestones.  ...
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Cobra head sign (ureter)

The cobra head sign (or spring onion sign) refers to dilatation of the distal ureter, surrounded by a thin lucent line, which is seen in patients with an adult-type ureterocoele. The cobra head appearance indicates an uncomplicated ureterocele. The lucent "hood" of the cobra represents the comb...
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Cobweb sign of arterial dissection

The cobweb sign is seen in cases of arterial dissection (usually aortic dissection) on CT angiogram (CTA) examinations and represents strands or ribbons of media crossing the false lumen, and appearing as thin filiform filling defects. Although it is a specific sign for the false lumen, it is i...
Article

Coca-Cola bottle sign (thyroid eye disease)

The Coca-Cola bottle sign refers to the appearance of the muscles of the orbit in thyroid eye disease.  The belly of the muscle enlarges with sparing of the tendinous insertion, giving the appearance of the traditional Coca-Cola bottle. The enlargement of the muscles follows the I'M SLOW format...
Article

Cockade sign (intraosseous lipoma)

The cockade sign is a classic appearance of an intraosseous lipoma of the calcaneus which presents as a well-defined lytic lesion with a central calcification resembling a cockade.  It is named after a cockade, which is a badge, usually in the form of a rosette or knot, generally worn on the hat.
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Codman triangle periosteal reaction

Codman triangle is a type of periosteal reaction seen with aggressive bone lesions. With aggressive lesions, the periosteum does not have time to ossify with shells of new bone (e.g. as seen in single layer and multilayered periosteal reaction), so only the edge of the raised periosteum will oss...
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Coffee-bean sign (sigmoid colon)

The coffee-bean sign (also known as the kidney bean sign or bent inner tube sign 4) is a sign on an abdominal plain radiograph of a sigmoid volvulus although some authors have also used the term to refer to closed loop small bowel obstructions. Caecal volvulus may be mistaken with sigmoid volvul...
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Cogwheel sign

The cogwheel sign refers to an imaging appearance in pelvic imaging of thickening loops of the Fallopian tube seen on cross-section. There are infolding projections (sometimes looking like nodules) into the Fallopian tube lumen which is likened to that of a cogwheel. The sign is typically descri...
Article

Coin lesion (lung)

Coin lesion refers to a round or oval, well-circumscribed solitary pulmonary lesion. It is usually 1-5 cm in diameter and calcification may or may not be present 1,3. Typically, but not always, the patient is asymptomatic 1.  Differential diagnosis The differential diagnosis for such lesions i...
Article

Colon cut-off sign

Colon cut-off sign describes gaseous distension seen in proximal colon associated with narrowing of the splenic flexure in cases of acute pancreatitis. Though originally described in abdominal radiographs, this sign has also been demonstrated in contrast enemas and computed tomography 1. This a...
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Comb sign (mesentery)

The comb sign refers to the hypervascular appearance of the mesentery in active Crohn disease.  Fibrofatty proliferation and perivascular inflammatory infiltration outline the distended intestinal arcades. This forms linear densities on the mesenteric side of the affected segments of small bowel...
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Comet tail sign (chest)

The comet tail sign is a finding that can be seen on CT scans of the chest. It consists of a curvilinear opacity that extends from a subpleural "mass" toward the ipsilateral hilum. The comet tail sign is produced by the distortion of vessels and bronchi that lead to an adjacent area of round ate...
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Comet tail sign (phleboliths)

Comet tail sign (in urological imaging) is helpful in distinguishing a ureteric calculus from a phlebolith and strongly favours the latter.  The sign refers to a tail of soft tissue extending from a calcification, representing the collapsed/scarred/thrombosed parent vein. When well seen it is s...
Article

Concentric ring sign

The concentric ring sign is a pathognomonic sign for a subacute haematoma on MRI. A subacute haematoma may show 3 characteristic layers of signal intensity: a thin peripheral rim of low signal intensity on all pulse sequences corresponding to haemosiderin. an inner peripheral high-signal inte...
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Cone-shaped caecum (differential)

A cone-shaped caecum refers to a loss of the normal rounded appearance of the caecum, which instead becomes narrow and cone-shaped with the apex pointing towards the base of the appendix. It is encountered in a number of conditions including: inflammatory infective blastomycosis amoebiasis ...
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Continuous diaphragm sign

The continuous diaphragm sign is a chest radiograph sign of pneumomediastinum or pneumopericardium if lucency is above the diaphragm, or of pneumoperitoneum if lucency is below the diaphragm.  Normally the central portion of the diaphragm is not discretely visualised on chest radiographs as it ...
Article

Convoluted cerebriform pattern

A convoluted cerebriform pattern is a term used to denote the appearance of a sinonasal inverted papilloma on MRI. The appearance is seen on both T2 and post contrast T1 images and appears as alternating roughly parallel lines of high and low signal intensity. This sign has been reported as pre...
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Cookie bite skeletal metastases

Cookie bite metastases are characterised by small focal eccentric lytic external cortical destruction in long tubular bones. This type of destruction is typically described for metastases from bronchogenic carcinoma, however they can also occur with other tumours.
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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. Clinical presentation The appearance of copper beaten skull is associated with raised intracranial pres...
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Cord sign (dural sinus thrombosis)

The cord sign 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 runs approximately in the axial plane s...
Article

Corduroy sign (vertebral haemangioma)

The corduroy sign refers to vertically-oriented, thickened trabeculae seen in intraosseous haemangiomas of the spine. It is the sagittal/coronal equivalent of the polka-dot sign seen on axial imaging.  It is caused by the replacement of the normal cancellous bone by thickened vertical trabecula...
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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 volvulus 1. In patients with malrotation and volvulus, the distal duodenum and proximal jejunum do not cross the mid...
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Cortical rim sign

The cortical rim sign is useful in distinguishing acute pyelonephritis from a segmental renal infarct and is seen on contrast enhanced CT or MRI. The wedges of reduced enhancement seen in the setting of acute pyelonephritis represent oedema and ischaemia which involves the whole wedge of renal ...
Article

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...
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Cottage loaf sign (liver)

The cottage loaf sign occurs as a result of a right-sided diaphragmatic rupture with partial herniation of the liver through the diaphragmatic defect. The herniated component is separated by a waist at the diaphragm from the larger intra-abdominal component. This shape is reminiscent of a cottag...
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Cotton wool appearance (bone)

The cotton wool appearance is a plain film sign of Paget disease and results from thickened, disorganized trabeculae which lead to areas of sclerosis in a previously lucent area of bone, typically the skull. These sclerotic patches are poorly defined and fluffy. See also Other Paget disease re...
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Courvoisier sign (hepatobiliary)

Courvoisier sign or Courvoisier-Terrier sign states that in a patient with painless jaundice and an enlarged gallbladder (or right upper quadrant mass), the cause is unlikely to be gallstones and therefore presumes the cause to be an obstructing pancreatic or biliary neoplasm until proven otherw...
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Coxa magna

Coxa magna is the asymmetrical, circumferential enlargement and deformation of the femoral head and neck. Definitions in the literature vary but enlargement with asymmetry >10% in size is a reasonable cut-off for diagnosis 1.  Pathology Aetiology Legg-Calve-Perthes disease transient synoviti...
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Coxa profunda

Coxa profunda refers to a deep acetabular socket. On pelvis x-rays it is seen as the acetabular fossa being medial to the ilioischial line. It should be differentiated from protrusio acetabuli, where the femoral head is seen additionally medial to the ilioischial line. Coxa profunda is much more...
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Coxa valga

Coxa valga describes a deformity of the hip where there is an 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 ...
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Craniotabes

Craniotabes is defined as a softening of the skull bones that may be normally present in newborns.    
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Crazy paving

Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular reticular thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.  Pathology Aetiology Common causes: acute respira...
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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 bands ...
Article

Crescent sign of arterial dissection

The crescent sign refers to the high signal crescent seen in the wall of a vessel when dissected. This may be seen both on T1 or T2 sequences depending on the age of the blood (see ageing blood on MRI). It is classically referred to in internal carotid artery dissection. It should not be confus...
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Crescent sign of avascular necrosis

The crescent sign of avascular necrosis is seen on conventional radiographs and refers to a linear area of subchondral lucency seen most frequently in the anterolateral aspect of the proximal femoral head (which is optimally depicted on the frog-leg radiographic view). It indicates imminent arti...
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Crossing sign (knee)

The crossing sign is seen on true lateral plain radiographs of the knee when the line of the trochlear groove crosses the anterior border of one of the condyle trochlea. It is a predictor of trochlear dysplasia. Trochlear dysplasia has been linked to recurrent patellar dislocation1,2,4. The cros...
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Crow feet sign (round atelectasis)

Crow feet sign is a characteristic but uncommon feature seen in round atelectasis. On CT, this is seen as linear bands radiating from a mass into adjacent lung tissue resembling the feet of a crow. This sign should not be confused with fibrotic changes occurring in the lung.
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CSF cleft sign

The CSF cleft sign in neuroimaging can be used to distinguish an extra-axial lesion from an intra-axial lesion, and is typically used in the description of a meningioma. Classically, the cleft was regarded as representing a thin rim of CSF between tumour and brain parenchyma. However, it often ...
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C sign (talocalcaneal coalition)

The C sign is an important radiological sign which may be seen on a lateral radiograph of the ankle in those with a tarsal coalition (talocalcaneal coalition).  Radiographic appearance A continuous C-shaped arc is seen on a lateral ankle radiograph which is formed by the medial outline of the ...
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CT angiogram sign (lungs)

The CT angiogram sign refers to vessels appearing prominent during a contrast enhanced CT as they traverse an airless low attenuation portion of consolidated lung. Although initially thought to be specific for bronchoalveolar carcinoma, it has now been recognised as a generic appearance provided...
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CT angiographic spot sign

The CT angiographic (CTA) spot sign is defined as unifocal or multifocal contrast enhancement within an acute primary intracerebral haemorrhage (ICH) visible on CTA source images and discontinuous from adjacent normal or abnormal blood vessels 1. It should not be present on pre-contrast images. ...
Article

CT comma sign

The CT comma sign is a characteristic sign seen in head trauma. It is the presence of concurrent epidural and subdural haematomas, which gives the characteristic appearance of this sign as a "comma" shape.
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Cupola sign (pneumoperitoneum)

The cupola sign is seen on a supine chest/abdominal radiograph in the presence of pneumoperitoneum.  It refers to non-dependent gas that rises within the abdominal cavity of the supine patient to accumulate underneath the central tendon of the diaphragm in the midline. It is seen as lucency ove...
Article

Curtain sign

The curtain sign (or draped curtain sign) in neuroimaging refers to the appearance of a vertebral body mass that extends to the anterior epidural space. The posterior longitudinal ligament is strongly attached to the posterior vertebral body cortex in the midline and is more loosely attached la...
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Cyclops lesion (knee)

The cyclops lesion, also known as localised anterior arthrofibrosis, is a painful anterior knee mass that arises as a complication of anterior cruciate ligament (ACL) reconstruction. Epidemiology Cyclops lesions occur with an estimated frequency of ~5% (range 1-9.8%) of patients following ACL ...
Article

Cyst with dot sign (neurocysticercosis)

The cyst with dot sign is seen in neurocysticercosis and represents the parasitic cyst with, usually eccentric, scolex. It can be seen on both MRI and CT at: the vesicular stage (CSF density / intensity cyst - denser / hyperintense scolex) and colloidal vesicular stage (enhancement of wall an...
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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.
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Dark bronchus sign

The dark bronchus sign is the appearance of a relatively darker bronchus as compared to adjacent ground glass opacity. If the ground glass opacity progresses to consolidation, air bronchograms will be visualised.  This sign is useful to identify diffuse ground glass opacity on HRCT chest in cas...
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Dawson fingers

Dawson fingers are a radiographic feature depicting demyelinating plaques through the corpus callosum, arranged at right angles along medullary veins (callososeptal location). They are a relatively specific sign for multiple sclerosis (MS), which presents as T2 hyperintensities. History and ety...
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Deep sulcus sign

The deep sulcus sign on a supine chest radiograph raises suspicion of a pneumothorax. On a supine plain chest film (common in intensive care units or as part of a trauma radiograph series), it may be the only suggestion of a pneumothorax because air collects anteriorly and basally, within the n...
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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 nephrographic phase images. A delayed nephrogram is characteristically unilateral and is usually distinguished...
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Dense hilum sign

The dense hilum sign suggests a pathological process at the hilum or in the lung anterior or posterior to the hilum. Malignancy, especially lung cancer, should be suspected. Radiographic features On a well-centred chest posteroanterior (PA) radiograph the density of the hilum is comparable on ...
Article

Dependent viscera sign

The dependent viscera sign is one of the signs of diaphragmatic rupture on axial CT or MR images, where herniated viscera lie against the posterior thoracic wall in a dependent position, as they are no longer supported by the diaphragm. See also  collar sign (or hourglass sign)
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Dinner fork deformity (wrist)

A dinner fork deformity, also known as a bayonet deformity, occurs as the result of a malunited distal radial fracture, usually a Colles fracture. The distal fragment is dorsally angulated, displaced and often also impacted. The term is descriptive, as the lateral view of the wrist is similar to...
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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 oedema at the time of an is...
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Disc herniation

Disc herniation refers to the displacement of intervertebral disc material beyond the normal confines of the disc but involving less than 25% of the circumference (to distinguish it from a disc bulge. A herniation may contain nucleus pulposus, vertebral endplate cartilage, apophyseal bone/osteop...
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Disproportionate posterior horn sign

The disproportionate posterior horn sign is a feature described with a meniscal tear having a posteriorly flipped fragment. Pathology Bucket handle tears of meniscus of the knee joint constitute 10% of meniscal tears. They consist of a vertical or longitudinal tear (which includes vertical-obl...
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Distal intersection syndrome

The distal intersection syndrome relates to tenosynovitis of the extensor pollicis longus (EPL) tendon, where it crosses the extensor carpi radialis longus (ECRL) and brevis (ECRB) tendons 1. It is distinct from intersection syndrome which occurs more proximally in the forearm at the intersectio...
Article

Doge cap sign

The doge cap sign is a radiographic sign of pneumoperitoneum. It presents as a triangular-shaped gas lucency in the right upper quadrant on abdominal radiographs due to air in the Morison pouch, which resembles the medieval caps worn by Italian doges.
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Dog leg sign

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 ...
Article

Dot dash pattern

The dot-dash pattern (dermoid mesh) is one of the characteristic sonographic appearances of an ovarian dermoid cyst. It refers to the short and long echogenic lines which are often seen within a dermoid cyst and are due to the presence of hair.
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Dot in a circle sign

Dot in a circle sign is an MRI sign for maduromycosis or mycetoma. It is described as a classic appearance on T2 weighted images which show a small rounded hyperintensity (representing granulation tissue), surrounded by a low signal intensity rim (representing fibrous septa) with a hypointense ...
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Double axillary pouch sign

The double axillary pouch sign is a collection of fluid between a torn anteroinferior glenoid labrum and the glenoid rim, giving the appearance of a second axillary pouch. The sign is seen best with MR arthrography on the coronal view, and is considered by some, a very specific sign for an ante...
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Double barrel sign (disambiguation)

Double barrel sign is an imaging appearance of two lumens adjacent to each other. It can be seen in: dilated bile duct adjacent to portal vein double barrel aorta: aortic dissection double barrel oesophagus: oesophageal dissection
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Double bleb sign

A double bleb sign is a sonographic feature where there is visualisation of a gestational sac containing a yolk sac and amniotic sac giving an appearence of two small bubbles 2. The embryonic disc is located between the two bubbles. It is an important feature of an intrauterine pregnancy and thu...
Article

Double bubble sign (duodenum)

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...
Article

Double contour cartilage line

Double contour cartilage line is a sign in ultrasonography of the gout arthropathy which is characterised 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 car...
Article

Double contour sign (trochlear dysplasia)

The double contour sign is a helpful radiologic sign which is seen on true lateral plain radiographs of trochlear dysplasia.  A double line at the anterior aspect of condyles that seen if medial condyle is hypoplastic. See also crossing sign of trochlear dysplasia
Article

Double decidual sac sign

The double decidual sac sign (DDSS) is a useful feature on early pregnancy ultrasound to confirm an early intrauterine pregnancy (IUP) when the yolk sac or embryo is still not visualised. It consists of the decidua parietalis (lining the uterine cavity) and decidua capsularis (lining the gestati...
Article

Double delta sign

The double delta sign is a feature that has been described in a bucket handle meniscal tear when the inner meniscal fragment flipped anteriorly adjacent to the anterior horn of the donor site and is referred to as a displaced bucket handle tear. The original location of the posterior horn remain...
Article

Double density sign (berry aneurysm)

Double density sign of berry aneurysms refers to the angiographic appearance of a small intracranial aneurysm projecting in front or behind a vessel of similar calibre. As such, the border of the aneurysm cannot easily be seen, but the extra contrast within it can be seen as a rounded area of in...
Article

Double density sign (left atrium)

The double-density sign is seen on frontal chest radiographs in the presence of left atrial enlargement, and occurs when the right side of the left atrium pushes behind the right cardiac shadow, indenting the adjacent lung and forming its own distinct silhouette 1-3.  If large enough, the left ...
Article

Double density sign (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...
Article

Double diaphragm sign

The double diaphragm sign is one of several radiological signs seen with a pneumothorax in a supine patient. Supine films are commonly performed in unwell patients, particularly in the ICU. In a supine patient with a pneumothorax, air may outline the anterior portions of the hemidiaphragm and c...
Article

Double disc sign

Thickening of the insertion of the lateral pterygoid muscle can mimic an anterior displaced temporomandibular disc. When both thickening of the inferior belly insertion and an anteriorly displaced disc are present, the two structures parallel each other; the so-called "double disc" sign.
Article

Double duct sign

The double duct sign refers to the presence of simultaneous dilatation of the common bile and pancreatic ducts. Being an anatomical sign it can be seen on all modalities that can visualise the region, including: MRI, CT, ultrasound and endoscopic retrograde cholangiopancreatography (ERCP).  The...
Article

Double line sign

The double line sign is an MRI finding seen at the periphery of a region of osteonecrosis (avascular necrosis, bone infarct). It is best seen on T2 weighted sequences and consists of an inner bright T2 line representing granulation tissue and an outer dark line representing sclerotic bone. This ...
Article

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. This pattern is likened to an Oreo cookie with two layers of (white) cream and three l...
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 in Wilson disease. The midbrain face of the giant panda sign consists of normal intensity of red n...
Article

Double PCL sign

The double PCL sign appears on sagittal MRI images of the knee when a bucket-handle meniscal tear (medial meniscus in 80% of cases) flips towards the centre of the joint so that it comes to lie anteroinferior to the posterior cruciate ligament (PCL) mimicking a second smaller PCL. A double PCL ...
Article

Double target sign (hepatic abscess)

The double target sign is a characteristic imaging feature of liver abscess demonstrated 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) d...

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