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.

722 results found
Article

Gull wing appearance (phalanges)

The Gull-wing appearance  (also known as seagull erosions) is seen in erosive osteoarthritis, typically on posteroanterior (PA) radiographs. The combination of cartilage space loss, central subchondral erosions, and marginal osteophyte proliferation results in a gull-wing appearance.
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Gut signature sign

The gut signature sign is an ultrasound term used to describe the appearance of the gastrointestinal wall. Radiographic features  Ultrasound Bowel has 5 layers, comprised of alternating hyperechoic and hypoechoic layers. Anatomically these layers are as follows (innermost to outermost) 1,2: ...
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Guttman sign (larynx)

Guttman sign is a clinical sign relating to the function of the larynx. In normal subjects, frontal pressure on the thyroid cartilage lowers the tone of voice produced and lateral pressure produces a higher tone of voice. The opposite is true with paralysis of the cricothyroid muscle.
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H-shaped vertebra

H-shaped vertebrae, also known as Lincoln log vertebrae, are a characteristic finding of sharply delimited central endplate depression, classically seen in approximately 10% of patients with sickle-cell anaemia, and results from microvascular endplate infarction (figure 1)3. It may occasionally...
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Haematocrit effect

The haematocrit effect with fluid-fluid levels is the result by layering of heavier cellular elements of blood located dependent to liquid supernatant may be seen on CT or MRI. It is most frequently seen in the setting of anticoagulation therapy or coagulopathy. See also signal flare phenomenon
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Haemorrhage exclusion sign (prostate)

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

The haemosiderin cap sign refers to an MR imaging feature in some spinal tumours where a cap of T2 hypointense haemosiderin is above and/or below the tumour due to previous haemorrhage.  It is most often associated with spinal cord ependymomas, being seen in 20-33% of these cases 1. The sign, h...
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Hair on end sign (mnemonic)

The hair on end sign refers to a radiographic appearance of a skull which results from a periosteal reaction manifesting as perpendicular trabeculations interspersed by radiolucent marrow hyperplasia along the skull vault. It is classically described with plain skull radiographs although can als...
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Hairy pleural plaques

The so-called hairy pleural plaque, are a manifestation of asbestos related disease. They arises from the visceral pleura, typically from an interlobar fissure. The hairiness stems from short radially oriented linear regions of fibrosis extending from the plaque into the adjacent lung parenchyma...
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Halo sign (chest)

The halo sign (HS) in chest imaging is a feature seen on lung window settings (typically HRCT), ground glass opacity surrounding a pulmonary nodule or mass and represents haemorrhage. It is typically seen in angioinvasive aspergillosis. Pathology Histopathologically, it represents a focus of p...
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Hampton hump

Hampton hump refers to a dome-shaped, pleural-based opacification in the lung most commonly due to pulmonary embolism and lung infarction (it can also result from other causes of pulmonary infarction (e.g. vascular occlusion due to angioinvasive aspergillosis). While a pulmonary artery embolism ...
Article

Hampton line

The Hampton line is a thin millimetric radiolucent line seen at the neck of a gastric ulcer in barium studies (profile view), indicating its benign nature. It is caused by a thin line of mucosa overhanging the ulcer's crater.
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Hanging noose sign

Hanging noose sign in obstretric imaging is a rarely described but classical finding of a true umbilical cord knot. It demonstrates a transverse section of the umbilical cord surrounded by a loop of umbilical cord and changes in the pressure of the knot can be demonstrated with the fetus movemen...
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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.
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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...
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Hatchet sign (ankylosing spondylitis)

Hatchet sign refers to the limited erosion of the lateral aspect of humeral head that produces a hatchet shaped deformity. This finding is typically associated with ankylosing spondylitis. In the absence of osteoporosis and presence of sclerosis this sign helps to differentiate it from rheumato...
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Hawkins sign (talus)

Hawkins sign describes subchondral lucency of the talar dome that occurs secondary to subchondral atrophy 6-8 weeks after a talar neck fracture 1. This indicates that there is sufficient vascularity in the talus, and is therefore unlikely to develop avascular necrosis later 2,3. Disruption of ...
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Haystack sign (pneumomediastinum)

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. 
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Head cheese sign (lungs)

The head cheese sign refers to a juxtaposition of regions with three different densities: ground glass opacities (high attenuation) mosaic attenuation pattern (low attenuation) normal lung tissue (normal attenuation) A mixed infiltrative (GGO) and obstructive (mosaic attenuation) disease pro...
Article

Heel pad sign

Increased heel pad thickness, also known as the heel pad sign, is seen in a number of conditions and relates to an increase in the soft-tissue thickness of the heel pad on lateral ankle radiographs.   The heel pad should normally be < 21mm. However, in certain situations, this is increased: ac...
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Hemithorax white-out (differential)

Complete white-out of a hemithorax on the chest x-ray has a limited number of causes. The differential diagnosis can be shortened further with one simple observation: the position of the trachea. Is it central, pulled or pushed from the side of opacification? Trachea pulled toward the opacified...
Article

Hennebert sign (inner ear)

The Hennebert sign describes a positive fistula test without clinical evidence of middle ear or mastoid disease. It is associated with congenital syphilis and may also be present in Meniere disease. It has been postulated that the vestibular stimulation is mediated by fibrous bands between foot...
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Hidebound sign (bowel)

The hidebound bowel sign refers to an appearance on a barium study of the small bowel in patients with scleroderma. The sign describes the narrow separation between the valvulae conniventes which are of normal thickness despite dilatation of the bowel lumen.   Although the term hidebound is use...
Article

High-attenuation crescent sign

The high attenuating crescent sign represents an acute haematoma within either the mural thrombus or the aneurysm wall, especially when detected on unenhanced CT scans. It is a specific sign of impending abdominal aortic aneurysm (AAA) rupture or so-called contained rupture. Pathology The hype...
Article

Higoumenakis sign (clavicle)

Higoumenakis sign is the unilateral enlargement of the sternal end of the clavicle in patients with late congenital syphilis. Pathology Treponema pallidum becomes readily localized in the lymphatic spaces and may remain in the connective tissues without manifestation in childhood. Through mech...
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Hilum convergence sign

The hilum convergence sign is a useful chest radiograph sign to help distinguish a bulky hilum due to pulmonary artery dilatation from a mass/nodal enlargement. In the former, pulmonary vessels can be seen to converge and join a dilated pulmonary artery.  History and etymology Dr Benjamin Fels...
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Hilum overlay sign

The hilum overlay sign refers to the appearance of an abnormally dense hilum on frontal chest radiographs. If a mass arises from the hilum, the normal pulmonary vessels (interlobar artery, upper lobe arteries, and left descending artery) 2 are in contact with the mass and their silhouette is ob...
Article

Hitchhiker thumb deformity

Hitchhiker thumb deformity refers to: flexion of the metacarpophalangeal (MCP) and extension of distal interphalangeal joint of the thumb It is similar to how a person would normally angulate and hold out the thumb with the intension to hitchhike. It is one of the musculoskeletal manifestatio...
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Hockey stick sign (Creutzfeldt-Jakob disease)

The hockey stick sign refers to the hyperintense signal involving the pulvinar and dorsomedial thalamic nuclei bilaterally on FLAIR, in cases of variant Creutzfeldt-Jakob disease, which has the shape of a hockey stick. See also pulvinar sign (Creutzfeldt-Jakob disease) hockey stick sign (thyr...
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Hockey stick sign (thyroid hemiagenesis)

Hockey stick sign has been used to described the appearance of the thyroid gland in cases of thyroid hemiagenesis, when investigated with 99m Technetium pertechnetate thyroid scan 1. The unilateral lobe and isthmus make a shape reminiscent of a hockey stick.  See also hockey stick sign (Creutz...
Article

Hoffman-Rigler sign (heart)

The Hoffman-Rigler sign is a sign of left ventricular enlargement where an approximation of the distance between the inferior vena cava (IVC) and left ventricle is used.​ Radiographic features On a lateral chest radiograph, if the distance between the left ventricular border and the posterior ...
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Hole within a hole sign

The hole within a hole sign or (bevelled edge sign) is described with patient with eosinophilic granulomas. A bevelled edge of the defects indicates destruction of the two tables (e.g. of the skull) to a differing degree (more at the inner table), resulting in a formation of two different lucent...
Article

Holly leaf sign

The holly leaf sign refers to the appearance of pleural plaques on chest x-rays. Their irregular thickened nodular edges are likened to the appearance of a holly leaf.
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Holman-Miller sign (maxillary sinus)

The Holman-Miller sign (also called antral sign) is seen in juvenile nasopharyngeal angiofibroma. The anterior bowing of the posterior wall of the maxillary antrum which is seen on lateral skull film or cross-sectional imaging 1-2. This is a non-specific sign that can be produced by any slowly ...
Article

Honda sign (sacrum)

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

Honeycombing refers to the computed tomographic (CT) manifestation of diffuse pulmonary fibrosis (usual interstitial pneumonia). The Fleischner Society definition is clustered cystic air spaces (between 3-10 mm in diameter but occasionally as large as 2.5 cm) which are usually subpleural and bas...
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Hot cross bun sign (pons)

The hot cross bun sign refers to the MRI appearance of the pons in a variety of neurodegenerative diseases.  T2 hyperintensity forms a cross on axial images through the pons, representing selective degeneration of pontocerebellar tracts. It has been described in 1: multiple-system atrophy (MSA...
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Hot nose sign

The hot nose sign refers to increased perfusion in the nasal region on nuclear medicine cerebral perfusion studies in the setting of brain death. The absent or reduced flow in the internal carotid arteries is thought to lead to increased flow within the external carotid arteries and subsequent i...
Article

Howship-Romberg sign

Howship-Romberg sign refers to obturator nerve neuropathy due to compression of it, by an obturator hernia. Patients present with pain and paresthesia along the inner aspect of the thigh, down to the knee.
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Hummingbird sign (midbrain)

The hummingbird sign, also known as the penguin sign, refers to the appearance of the brainstem in patients with progressive supranuclear palsy (PSP).  The atrophy of the midbrain results in a profile of the brainstem (in the sagittal plane) in which the preserved pons forms the body of the bir...
Article

Hutchinson pupil

Hutchinson pupil is a fixed and dilated pupil caused by compression of the oculomotor nerve (CN III) as a result of uncal herniation. It should not be confused with any of the following: Hutchinson's triad Hutchinson freckle Hutchinson teeth Hutchinson's sign Hutchinson syndrome History a...
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Hutchinson sign (disambiguation)

The Hutchinson sign can refer to two signs.  Hutchinson sign (ophthalmology) Relates to involvement of the tip of the nose from facial herpes zoster. It implies involvement of the external nasal branch of the nasociliary nerve (branch of the ophthalmic division of the trigeminal nerve) and thu...
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Hutchinson teeth

Hutchinson’s teeth are smaller and more widely spaced than normal and are notched on their biting surfaces. It is a sign of congenital syphilis and should not be confused with: Hutchinson's triad Hutchinson pupil Hutchinson freckle Hutchinson's sign Hutchinson syndrome History and etymolo...
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Hutchinson triad

Hutchinson triad of congenital syphilis consists of: dental abnormalities interstitial keratosis deafness History and etymology Named after Sir Johnathan Hutchinson, English surgeon, ophthalmologist and pathologist (1828 - 1913). Hutchinson's triad should not be confused with: Hutchinson ...
Article

Hydatid cyst signs

There are several signs in hydatid cyst are seen in associated with hydatid disease: cumbo sign: air is seen between the pericyst  and the laminated membrane of the cyst  serpent sign: internal rupture of the cyst with collapse of membranes of parasite into the cyst spin sign/whirl sign: deta...
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Hyoid elevation

Hyoid elevation is an indication on a modified barium swallow study that the pharyngeal muscles are contracting appropriately. Radiographic features Modified barium swallow With real time fluoroscopy (or videofluoroscopy) during the act of swallowing, the larynx moves upward and forward when ...
Article

Hyperattenuating ring sign in epiploic appandagitis

The hyperattenuating ring sign is a sign that has been described with epiploic appendagitis and refers to a hyperattenuating ring of visceral peritoneum surrounding a inflammed epiploic appendix 1. On CT it can be seen as a ring of soft tissue surrounding a region of fat attenuation adjacent to ...
Article

Hypercontracting (nutcracker) oesophagus

Hypercontracting (nutcracker) oesophagus is a motility disorder of the oesophagus. This condition is primarily diagnosed with manometry with high intra-oesophageal pressure and normal peristalsis. Most patients will have a normal barium swallow.  Hypercontracting oesophagus ("nutcracker oesopha...
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Hyperdense MCA sign (brain)

The hyperdense MCA sign refers to focal increased density of the middle cerebral artery on CT and is direct visualisation of thromboembolic material within the lumen. It is thus the earliest visible sign of MCA infarction seen immediately at the time of embolism.  It is the longitudinal equivale...
Article

Ice pick sign

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

The ice cream cone sign may refer to: the appearance of the head of malleus and the body and short process of the incus on axial CT scan: failure of this normal configuration suggests incudomalleolar dysarticulation the ball of the ice cream is formed by the head of malleus and cone is formed ...
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Inanimate object inspired signs

Inanimate object inspired signs are numerous with many radiographic appearances likened to bottle, hooks, items of clothing, weapons etc...  They are listed below in the 'related articles' section.   
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Incidental lung nodules

Incidental lung nodules are encountered commonly in routine cross sectional imaging. The risk of developing cancer in very small nodules (<5mm) is very low. However, clear-cut recommendations are still not in place with high variation in practice amongst reporting radiologists 1. As a result, it...
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Incomplete border sign

The incomplete border sign is useful to depict an extrapulmonary mass on chest radiograph. An extrapulmonary mass will often have a inner well defined border and an ill-defined outer margin 1-3. This can be attributed to the inner margin being tangential to the x-ray beam and has good inherent ...
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Infundibulum sign (pituitary)

The infundibulum sign is helpful in distinguishing an empty pituitary sella from a cystic lesion of the pituitary region 1.  In the former, although the sella is enlarged, there is no mass as such and the pituitary infundibulum traverses the enlarged sella to its floor where residual pituitary ...
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.
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Interstitial line sign

The interstitial line sign is an ultrasound finding in interstitial ectopic pregnancy. It is an echogenic line from the mass to the endometrial echo complex. Reportedly it has high sensitivity (80%) and specificity (98%).
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Intrabiliary rupture of hepatic hydatid cyst

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

Intracranial arterial beading represents alternating areas of constriction in the intracranial arteries that gives the appearance of beads strung together. Differential diagnosis The various conditions where this is seen are: cerebral vasculitis radiation therapy cerebral vasospasm post sub...
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Intradecidual sac sign

Intradecidual sac sign (IDSS) is a useful feature in identifying an early intrauterine pregnancy (IUP) as early as 25 days of gestation 1. The threshold level (earliest one can see the sign) is 24 days of gestation and the discriminatory level (one should always see the sac) is 47 days. As per t...
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Intrahepatic arterioportal shunt

Intrahepatic arterioportal shunts represent abnormal flow between the portal venous system and a hepatic arterial system within the liver. They can be a reversible cause of portal hypertension. Clinical presentation Clinical features will depend on size and other underlying pathology. Small sh...
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Intramural bowel gas

Intramural bowel gas, also known as pneumatosis intestinalis, refers to the clinical or radiologically finding of gas within the wall of the bowel. Terminology There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cysto...
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Inverted "V" sign

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

Inverted Napoleon hat sign

The inverted Napoleon hat sign is a radiologic sign seen on the frontal pelvic or lumbar radiograph at the level of the 5th lumbar vertebra and the sacrum. It is seen when there is bilateral spondylolysis with marked anterolisthesis of L5 on S1 or marked exaggeration of the normal lordosis at t...
Article

Ivory phalanx

Ivory phalanx is a finding of increased radiodensity of an entire phalanx as a result of periosteal and endosteal bone formation. This sign is a unique and specific radiographic manifestation of psoriatic arthritis, yet it is uncommon and thus of low sensitivity. Nevertheless, it is of particul...
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Ivory vertebra sign

The ivory vertebra sign refers to diffuse and homogeneous increase in opacity of a vertebral body that otherwise retains its size and contours, and with no change in the opacity and size of adjacent intervertebral discs. Pathology Aetiology The cause for an ivory vertebra depends on the age o...
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Ivy sign (brain)

The ivy sign refers to the MRI appearance of patients with moya moya disease or moya moya syndrome. Prominent leptomeningeal collaterals result in vivid contrast enhancement and high signal on FLAIR due to slow flow. The appearance is reminiscent of the brain having been covered with ivy. Diffe...
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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-shaped sella includes 1,...
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J sign (shoulder)

The J sign refers to the appearance of the inferior glenohumeral ligament in the presence of a humeral avulsion of the glenohumeral ligament (HAGL lesion). The normal U-shaped inferior glenohumeral recess is retracted away from the humerus, appearing as a J (right shoulder).
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Jack and Jill lesion

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

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

Juxtaphrenic peak sign

The juxtaphrenic peak sign or diaphragmatic tenting refers to the peaked or tented appearance of a hemidiaphragm which can occur in the setting of lobar collapse. It is caused by retraction of the lower end of diaphragm at an inferior accessory fissure (most common 1), major fissure or inferior ...
Article

Kernohan phenomenon

Kernohan notch phenomenon is an imaging finding resulting from extensive midline shift due to mass effect, resulting in indentation in the contralateral cerebral crus by the tentorium cerebelli. This has also been referred to as Kernohan-Woltman notch phenomenon and false localising sign. Clini...
Article

Kerr kink

Kerr Kink a sign of renal tuberculosis. Scarring leads to a sharp kink at the pelvi-ureteric junction.
Article

Keyhole sign (posterior urethral valves)

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

The kidney sweat sign applies to the presence of thin, hypoechoic, extracapsular fluid collections around kidneys in renal failure patients. This fluid is assumed to represent perirenal oedema. It can be appreciated on ultrasound, CT and MR imaging.  Differential diagnosis perirenal haematoma ...
Article

Kirklin complex

The Kirklin complex is a combination of the Carman meniscus sign associated with a radiolucent semi-circular zone surrounding the elevated ridge of the ulcer. This complex is seen in cases of gastric adenocarcinoma on barium studies. See also Carman meniscus sign
Article

Kirklin sign

The Kirklin sign refers to a deformity of the normal gastric air bubble on an upright chest radiograph due to a mass lesion of the gastric cardia or fundus. The differential for a Kirklin sign includes gastric tumour gastric carcinoma oesophageal carcinoma gastrointestinal stromal tumour (G...
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

Kissing carotids

The term kissing carotids refers to tortuous and elongated vessels which touch in the midline. They can be be found in:  retropharynx 2 intra-sphenoid 1 within the pituitary fossa within sphenoid sinuses within sphenoid bones The significance of kissing carotids is two-fold: may mimic int...
Article

Knuckle sign (pulmonary embolism)

Knuckle sign refers to the abrupt tapering or cutoff of a pulmonary artery secondary to embolus. It is better visualised on CT pulmonary angiography scan than chest x-ray. This is an important ancillary finding in pulmonary embolism (PE), and often associated with the Fleischner sign of dilated ...
Article

L sign (brain)

The L sign is one of the features useful in identifying the central sulcus on cross-sectional imaging. It relies on identifying the superior frontal sulcus which intersects the precentral sulcus in an "L" junction, thus defining the precentral gyrus. The central sulcus is the next posterior sul...
Article

Lambda sign

There are a number of lambda signs: lambda sign of twin pregnancy lambda sign of sarcoidosis
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Lambda sign (sarcoidosis)

The lambda sign is seen on gallium-67 scans in the setting of thoracic sarcoidosis. Bilateral hilar and right paratracheal lymph nodes are typically involved which can resemble the lambda symbol (λ). See also lambda sign of twin pregnancy
Article

Lateral crescent sign (inguinal hernia)

Lateral crescent sign is a useful diagnostic sign of a direct inguinal hernia on CT scan, the hernia causing compression and lateral displacement of the inguinal canal contents (ductus deferens, testicular vessels, fat, etc) to form a semicircle of tissue that resembles a moon crescent seen late...
Article

Lateral femoral notch sign (knee)

The (deep) lateral femoral notch sign describes a depression on the lateral femoral condyle at the terminal sulcus, a junction between the weight bearing tibial articular surface and the patellar articular surface of the femoral condyle. Pathology The likely mechanism is a hyperextension or im...
Article

Lead pipe sign

Lead pipe appearance of colon is the classical barium enema finding in chronic ulcerative colitis. There is complete loss of haustral markings in the diseased section of colon, and the organ appears smooth walled and cylindrical. 
Article

Lemon sign (cerebellum)

The lemon sign, noted on antenatal imaging, is one of the many notable fruit inspired signs. It is a feature when there appears to be an indentation of the frontal bone (depicting that of a lemon). It is classically seen as a sign of a Chiari II malformation and also seen in the majority (90-98%...
Article

Lentiform fork sign

The lentiform fork sign has been described on MRI seen as bilateral symmetrical hyperintensities in the basal ganglia surrounded by a more/brightly hyperintense rim delineating the lentiform nucleus. It has been postulated to result from metabolic acidosis due to any cause 1, e.g. end stage ren...
Article

Leopard skin sign (white matter)

The Leopard skin sign (also known as tigroid pattern or stripe sign) results from dark-spots or stripes (spared perivascular white matter) within bright demyelinated periventricular white matter on T2W images. It is characteristically seen in : metachromatic leukodystrophy Pelizaeus-Merzbacher...
Article

Lhermitte sign (spinal cord)

Lhermitte sign or the barber chair phenomenon is an electrical shock sensation running down the spine and into the limb on neck flexion. It suggests compression of the upper cervical spinal cord and/or brainstem. It is typically seen with multiple sclerosis but is also associated with other pat...
Article

Licked candy stick appearance (bones)

The term licked candy stick appearance refers to tapering of the tips of the metacarpal bones, metatarsal bones, phalanges or clavicles and is usually associated with: psoriatic arthropathy rheumatoid arthritis leprosy neuropathic joint
Article

Light bulb sign (hepatic haemangioma)

The light bulb sign of a hepatic haemangioma is a feature than can be seen on MRI imaging with a classic hepatic haemangioma. This refers to marked hyperintensity seen on heavily T2 weighted sequences that has been likened to a glowing light bulb. See also light bulb sign - shoulder light bul...

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