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.

188 results found
Article

Sharp mediastinum sign

The sharp mediastinum sign is a unique sign in neonatal chest x-rays for medial pneumothoraces or pneumomediastinum, especially as a complication to mechanical ventilation for respiratory distress syndrome (RDS). Radiographic features Plain radiograph As neonatal chest x-rays are taken with t...
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Curtain sign (lung ultrasound)

The curtain sign refers to the normal ultrasound characteristics of lung bases where the lungs are fully aerated. This is because the air in the costophrenic recess will cast a hyperechoic "air curtain" over the recess, obscuring the outline of the lateral diaphragm. The "air curtain" will also ...
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Superior triangle sign (right lower lobe collapse)

The superior triangle sign is seen with complete right lower lobe (RLL) collapse alone or combined with right middle lobe collapse on PA chest x-rays. This sign can be a useful indirect sign of right lower lobe collapse where typical features are absent. Radiographic features Plain radiograph ...
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Crescent sign (disambiguation)

The characteristic shape of the crescent has been given to many radiological signs over the years. crescent sign (disambiguation) crescent sign (arterial dissection) crescent sign (inguinal hernia) crescent sign (intravenous pyelogram) crescent sign (lung hydatid) crescent sign (osteonecro...
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Contrast level within inferior vena cava

A dependent contrast level within the inferior vena cava is a situation that can be observed in some cases with inferior vena caval contrast reflux. Its presence is usually associated with very poor cardiac output and can be accompanied by dependent layering of venous refluxed contrast within th...
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Inferior vena caval contrast reflux

Reflux of contrast into inferior vena cava can be common findings seen on CT. It is considered a specific but insensitive sign of right-sided heart disease / right heart dysfunction at low contrast injection rates although the usefulness decreases with high injection rates. Conditions associate...
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Kussmaul sign

Kussmaul sign is a clinical sign, seen as a paradoxical increase in the jugular venous pressure in response to inspiration. This is opposed to the normal physiological response of inspiration resulting in decreased jugular venous pressure 1. Pathology Etiology This sign typically arises secon...
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Trigonum parietale (azygos lobe)

The trigonum parietale refers to a triangular opacity seen on chest radiograph that correlates with a small piece of extrapleural areolar tissue that lies between the layers of pleura in the fissure of an azygos lobe 1-4. It may be seen at the most superior portion of the azygos fissure and shou...
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Blunting of the costophrenic angle

Blunting of the costophrenic angle (also known as blunting of the costophrenic sulcus) is a chest radiograph sign usually indicative of a small pleural effusion. It may be seen on either frontal or lateral erect projections. It has been found that approximately 200 mL pleural fluid needs to be p...
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Bird’s nest sign (lungs)

The bird’s nest sign refers to the appearance created by a reverse halo sign with associated irregular and intersecting areas of stranding or irregular lines within the area of ground-glass opacity 1. Both bird's nest sign and reverse halo signs are suggestive of invasive pulmonary fungal infec...
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Roesler sign

Roesler sign is the name given to the inferior rib notching seen in coarctation of the aorta. Although by no means pathognomonic, the sign is fairly specific. Although many other causes of inferior rib notching have been recorded most of them are very rare 1. Strictly-speaking it is only called...
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Doughnut sign (chest)

The doughnut sign can be appreciated on the lateral chest radiograph of patients with mediastinal adenopathy, most commonly seen in pediatric patients with pulmonary tuberculosis infection1. The sign is made up of precarinal, subcarinal and retrocarinal lymph nodes which surround the radiolucen...
Article

Pleural pointillism

Pleural pointillism is multiple high signal regions on b=1000 diffusion-weighted imaging but not at lower b-values. It can be a reliable tool allowing differentiation of malignant from benign pleural lesions and can help guide biopsy 1-3.  Its sensitivity is reported to be 93-100% and specificit...
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Pulmonary target sign

The pulmonary target sign has been described in the lung parenchyma as a central high attenuation focus surrounded by one or more dense complete or incomplete ring-like consolidation, forming one or more circles. This sign has been predominantly reported on non-contrast chest CT in patients with...
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Bunch of grapes sign (bronchiectasis)

The bunch of grapes sign, a.k.a. cluster of grapes sign, is a characteristic imaging finding on CT seen in bronchiectasis. Closely apposed dilated bronchi may look like multiple adjacent thin walled cysts which mimic the appearance of a bunch of grapes.
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Centrilobular micronodules

Centrilobular micronodules are an image descriptor that refers to centrilobular nodules when the nodules are very small and present in a centrilobular distribution in the lungs. They are usually seen with bronchiolitis and can blend into tree-in-bud opacities.  Radiographic features CT Postpr...
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Ring shadow (chest)

Ring shadows on chest x-ray are classically associated with cystic bronchiectasis 1,2 but the term has also been used to describe a normal bronchus imaged end-on 3. 
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Ring around artery sign

The ring around artery sign refers to a (semi-) circular radiolucency surrounding the right pulmonary artery caused by mediastinal air in the case of pneumomediastinum 1-3. The sign was originally described on lateral chest radiographs 1-4 but can be equally appreciated on sagittal multiplanar ...
Article

Sandwich sign (disambiguation)

The sandwich sign is used for two different imaging appearances: sandwich sign (Marchiafava-Bignami disease) sandwich sign (mesentery) Sandwich sign has also been coined for the appearance of: primary pleural lymphoma 1,2 mediastinal lymphoma 3 marrow edema and hemorrhage on MRI of flexion...
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Mosaic appearance (disambiguation)

The evocative appearance of a mosaic is used for two different entities: mosaic attenuation of the lungs mosaic pattern of Paget disease of the bone
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Cheerio sign (disambiguation)

The Cheerio sign has been described in two different scenarios: Cheerio sign (pulmonary nodule) Cheerio sign (shoulder)
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Small heart sign

The small heart sign represents a rarely encountered but critical sign on chest caused by a sudden reduction of heart size caused by cardiac tamponade due to either tension pneumopericardium or pneumomediastinum.  A sudden, >2 cm reduction in the transverse cardiac diameter is considered highly...
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Chen sign

Chen sign on chest radiography is the prominence of the left basal pulmonary vasculature, compared to the right, seen in valvular pulmonary stenosis. It is due to the asymmetric increase in pulmonary blood flow to the left lung due to preferential blood flow into the left pulmonary artery after ...
Article

Scimitar (disambiguation)

The term scimitar, referring to the characteristic shape of the Middle Eastern sword, may refer to the following: scimitar syndrome (lungs) scimitar sign (cystic adventitial disease) scimitar sacrum (bones)
Article

Retrocardiac sail sign

The retrocardiac sail sign represents the characteristic and highly specific appearance of left lower lobe collapse on a frontal chest x-ray. Radiographic appearance The collapsed, medially displaced left lower lobe is represented by a triangular area of increased density with sharp margins, s...
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Medial breast margin sign

The medial breast margin sign is a sign of pectus excavatum seen on the frontal chest radiographs of women. It is one of several described signs of pectus excavatum on frontal chest radiographs.  Radiographic features Plain radiograph Women with pectus excavatum may have a more vertically ori...
Article

Potato nodes

Potato nodes are a classical moniker for the large nodes seen in the lung hila and mediastinum on the chest radiograph in pulmonary sarcoidosis. This name is derived from the characteristic bulky irregular morphology of the nodes which is reminiscent of large lumpy potatoes. Although this appear...
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Cluster of black pearls sign

The "cluster of black pearls" sign refers to a finding on contrast-enhanced CT useful in differentiating sarcoidosis from other causes of lymphadenopathy such as tuberculosis, lymphoma and metastatic adenocarcinoma. The sign is depicted by the presence of multiple tiny round nodules (1-2 mm) di...
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Empty cyst sign

The empty cyst sign is described in hydatid disease. After rupture of the cyst and complete evacuation of its content, the pericyst becomes empty as an air-filled cyst on x-ray or CT 1,2. With superadded infection, an air-fluid level may appear within the cyst, mimicking a lung abscess 2.
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Crescent sign (lung hydatid)

The crescent sign is described in hydatid disease.  When the hydatid cyst erodes the adjacent bronchus or bronchiole, the trapped air between the pericyst and the laminated membrane of the endocyst gives a crescent-shaped rim of air around the cyst, thus is termed the crescent sign 1,2. It can b...
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Serpent sign

The serpent sign, a.k.a. snake sign, is described in hydatid disease. The WHO classification (2001) or Gharbi classification (1985) of hydatid disease describe several stages on ultrasound 1. During the active stage, the cyst is composed of three layers: the outer (pericyst), the middle (ectocy...
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Egg and banana sign (pulmonary hypertension)

The egg and banana sign is a sign for the diagnosis of pulmonary arterial hypertension (PAH) on axial CT/MR images. It refers to the appearance of the aortic arch (banana) next to a distorted main pulmonary artery (egg). Like an egg, the main pulmonary artery is preferentially dilated in the PA ...
Article

Pyrexia

Pyrexia (or fever) is a clinical sign, indicated by an abnormally elevated core body temperature, which is defined by several medical societies as ≥38.3°C (≥≈101°F). The temperature elevation may be persistent or episodic. If the body temperature is greater than 41.5°C - a rare phenomenon - it i...
Article

Doughnut sign (disambiguation)

The doughnut sign can refer to various imaging appearances: crescent in a doughnut sign (bowel) doughnut sign (bone scan) doughnut sign (bowel) doughnut sign (chest) doughnut sign (missed testicular torsion) doughnut sign (orbit)
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Jellyfish sign (ultrasound)

The jellyfish sign refers to the sonographic appearance of atelectatic lung "swimming" within a large pleural effusion. The mobility of the lung within pleural fluid implies an absence of lung consolidation and the absence of pleural adhesions 1. It is also suggestive of a transudative pleural e...
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Ginkgo leaf sign (disambiguation)

The ginkgo leaf sign can refer to: ginkgo leaf sign (chest) of chest wall surgical emphysema ginkgo leaf sign (spine) of spinal meningioma
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Deep sulcus sign (disambiguation)

The deep sulcus sign can refer to two different radiographic signs but is best known in the chest: deep sulcus sign (chest): of pneumothorax on supine CXR: deep sulcus sign (knee): better known as the lateral femoral notch sign of ACL injury
Article

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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Pericardial fat tag sign (pneumothorax)

The pericardial fat tag sign is a sign of pneumothorax on supine CXR where the cardiac border has a lumpy contour. When gas is located in the pleural space between the lung and mediastinum, the pericardial fat is no longer compressed against the mediastinum and therefore can hang or dangle late...
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Plankton sign (ultrasound)

The plankton sign refers to swirling, punctiform internal echoes within an otherwise anechoic pleural effusion which demonstrate slow, whirling dynamics, occasionally buffered by cardiac and respiratory impulses. When present, one may rule out a transudative effusion, and should be highly suspic...
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Positive bronchus sign

The positive bronchus sign is seen on CT chest, and refers to the presence of a bronchus leading directly to a peripheral lung lesion 1,2. In one study, four types of tumor-bronchi relationships were described 3: patent bronchus leads directly to the tumor mass bronchus is within the tumor ma...
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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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A-line (ultrasound)

An A-line is an ultrasonographic artifact appreciated during the 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...
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Rim sign (pulmonary infarction)

The rim sign can be seen in cases of pulmonary infarction on PET-CT with very mild peripheral continuous FDG uptake and the complete absence of central uptake. This is a different appearance to that seen in lung abscesses or necrotic tumors, whereby the peripheral FDG-avidity is marked. History...
Article

Esophageal intubation

Esophageal intubation refers to the incorrect placement of an endotracheal tube in the esophagus. Within minutes its consequences can be catastrophic with the seriousness of its outcome depending largely on the timeliness of its diagnosis. Epidemiology Accidental esophageal intubation can happ...
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Double lung point sign (Ultrasound)

The double lung point sign refers to a sharp boundary found between relatively aerated superior lung fields and coalescent "B‐lines" (representing interstitial edema) in the basal lung fields, with a reported sensitivity of 45.6%-76.7% and a specificity of 94.8%-100% 1,3 in diagnosing transient ...
Article

Double artery sign

The double artery sign refers to the appearance of a non-dilated mucus-filled bronchus adjacent to a pulmonary artery producing the appearance of a "double artery" on CT chest. This sign is considered a feature of a central endobronchial lesion such as a mucus plug or neoplasm.
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Signs of pulmonary embolus on chest radiography

There are several described signs of pulmonary embolus on chest radiography which are suggestive of this diagnosis. None are pathognomonic and need to be interpreted with caution with close regard to the clinical presentation. Chang sign Fleischner sign Hampton hump (strictly a sign of pulmon...
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Fleischner sign (disambiguation)

Fleischner sign can refer to two distinctly separate signs: Fleischner sign (enlarged pulmonary artery) Fleischner sign (tuberculosis of ileocecal junction)
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Palla sign

Palla sign is a sign seen on chest radiographs suggestive of pulmonary embolism, usually seen in the acute setting. Although uncommon, it can be seen along with several other described signs of pulmonary embolus on chest radiography. Pathology Palla sign describes an enlarged right descending...
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Costal hook sign (flail chest)

The costal hook sign is a chest x-ray feature seen in some cases of flail chest. It represents the rotation of a fractured rib along its long axis, something that is only possible if a second fracture is present along its length, even if the second fracture is not visible 1. 
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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...
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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...
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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...
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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/...
Article

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...
Article

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...
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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...
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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...
Article

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...
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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...
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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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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)
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Thymic sail sign

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

The thymic notch sign represents the normal thymus in a newborn on a frontal chest radiograph. Interruption of the cardiac silhouette forms a notch, which may be seen on either side, but more frequently is seen on the left side.   See also thymic sail sign thymic wave sign  
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Stag's antler sign (lungs)

The stag's antler sign, also known as the hands-up or inverted moustache sign, refers to upper lobe pulmonary venous diversion in pulmonary venous hypertension or pulmonary edema as seen on an erect frontal chest radiograph. The prominence of upper lobe pulmonary veins resembles a stag's antler...
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Knuckle sign (pulmonary embolism)

The knuckle sign refers to the abrupt tapering or cutoff of a pulmonary artery secondary to a pulmonary embolus (PE). It is better visualized on CT pulmonary angiography (CTPA) than chest x-ray. This is an important ancillary finding in pulmonary embolism, and often associated with the Fleischne...
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Pulmonary plethora

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

Pneumothorax is a serious potential consequence of blunt thoracic trauma and, if misdiagnosed, it may quickly become life-threatening. For a discussion on epidemiology, clinical presentation, pathology, and treatment and prognosis please see the main pneumothorax article.  Radiographic feature...
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Swiss cheese sign (lungs)

The Swiss cheese sign has been used for the appearance on CT of fluid-containing pneumatoceles, that typically occurs following pulmonary lacerations 1. They have also been described on CT appearances where there is pulmonary infection superimposed on emphysema 2. The pneumatocoeles appear as '...
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Snowman sign (disambiguation)

Snowman sign, also sometimes referred to as a figure of 8 sign or dumbell sign, is a radiologic sign related to conditions that have a shape which resembles a snowman. This include:  snowman sign (total anomalous pulmonary venous return) 1 snowman sign (pituitary macroadenoma) 2,3
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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. 
Article

Unfolded aorta

The term unfolded aorta refers to the widened and decreased curvature of the aortic arch on a frontal chest radiograph giving an ‘opened up’ appearance. It is one of the more common causes of apparent mediastinal widening and is seen with increasing age, usually associated with aortic calcificat...
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Kirklin sign

The Kirklin sign refers to a deformity of the normal gastric bubble on an upright chest radiograph due to a mass lesion of the gastric cardia or fundus. The Kirklin sign is different from the Kirklin complex, a gastric finding on upper GI fluoroscopy. History and etymology Byrl Raymond Kirkli...
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Extrapleural fat sign

The extrapleural fat sign is an imaging feature which can be seen on CT under certain circumstances. It occurs from the inward displacement of extrapleural fat by an extrapleural fluid collection, extrapleural hematoma or extrapleural mass. The presence of the extrapleural fat sign is indicative...
Article

Fallen lung sign

The fallen lung sign (also known as CT fallen lung sign) describes the appearance of collapsed lung away from the mediastinum encountered with tracheobronchial injury (in particular those >2 cm away from the carina). It is helpful to look for this rare but specific sign, in cases of unexplained ...
Article

Haystack sign (pneumomediastinum)

The haystack sign on chest radiographs in pediatric patients is indicative of pneumomediastinum. The pediatric heart is surrounded above and below with gas, giving it an appearance of a haystack from Monet's paintings. 
Article

Tram-track sign (chest)

Tram-track sign may be used in chest radiography or CT to denote the thickened non-tapering (parallel) walls of cylindrical bronchiectasis. It should not be confused with other tram-track signs elsewhere in the body. 
Article

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.
Article

Shred sign (lungs)

The shred sign, also known as the fractal sign, is a static sonographic sign of lung consolidation. Consolidated lung tissue appears as a subpleural hypoechoic region that has an irregular (shredded) deep border (fractal line) abutting normally aerated lung, which has echogenic artifacts. This ...
Article

Sinusoid sign (ultrasound)

The sinusoid sign is a dynamic sonographic sign, present when respiratory variation decreases the distance between the parietal and visceral pleura, when separated by a pleural effusion. Classically demonstrated in M-mode, the appearance of which the moniker is derived, it is specific for the id...
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Quad sign

The quad sign is a static sonographic sign observed in pleural effusion. It consists of four lines representing the pleura, rib, fluid, and lung. Similar to the sinusoid sign, this sign has a high sensitivity and specificity for pleural effusion, which - when simple - is itself anechoic.
Article

Fluid color sign

The fluid color sign is a diagnostic sign to differentiate a pleural effusion from pleural thickening by means of color Doppler ultrasound. In the case of pleural effusion a color signal is seen in the pleural fluid during respiratory and cardiac movement, whereas this color signal is not seen i...
Article

Dot in box appearance

A "dot in box" appearance is a pattern that has been described with pulmonary lymphangitis carcinomatosis.  The interlobular septal thickening from lymphangitis forms polygonal arcades accounting for the box while the prominence of the centrilobular bronchovascular bundle is thought to represent...
Article

Rigler notch sign (lungs)

The Rigler notch sign refers to an indentation in the border of a solid lung mass, which is thought to represents a feeding vessel, thus suggesting the presence of a bronchial carcinoma 1. However, this sign is also observed in other conditions, including granulomatous infections, and its differ...
Article

Dark bronchus sign

The dark bronchus sign is the appearance of a relatively darker bronchus as compared to adjacent ground glass opacity. Normally, the density of lung parenchyma and the bronchiolar lumen is similar. In cases of ground glass opacity, the bronchiolar lumen within the affected lung parenchyma appear...
Article

Silhouette sign (x-rays)

Silhouette sign is somewhat of a misnomer and in the true sense actually denotes the loss of a silhouette, thus, it is sometimes also known as loss of silhouette sign or loss of outline sign 4.  The differential attenuation of x-ray photons by two adjacent structures defines the silhouette, e.g...
Article

Chang sign (pulmonary embolism)

The Chang sign refers to the dilatation and abrupt change in caliber of the main pulmonary artery due to pulmonary embolism 1. It is one of several described signs of pulmonary embolus on chest radiographs. History and etymology It is named after C H Joseph Chang, (7 July 1929 - 15 November 20...
Article

Westermark sign

Westermark sign is a sign of pulmonary embolus seen on chest radiographs. It is one of several described signs of pulmonary embolus on chest radiographs. Pathology The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3. In one stu...
Article

Interface sign (HRCT chest)

The interface sign is a feature seen on HRCT chest imaging and refers to the presence of irregular interfaces at the margins of pulmonary parenchymal structures or the pleural surface of the lung. It suggests interstitial thickening.
Article

Coin lesion (lung)

A 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...
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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 also referred to as the figure of 8 sign. It is an abnormality of the fetal circulat...

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