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 continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
1,141 results found
Article
Bone marrow edema
Bone marrow edema is the term given to abnormal fluid signals seen within the bone marrow on MRI. It is a non-specific yet important imaging finding, usually indicating the presence of underlying pathology.
Terminology
The term edema was coined on MRI as the signal in abnormal bone marrow is s...
Article
Flashlight sign (B-flow)
The flashlight sign is a B-flow vascular ultrasound sign caused by wall adherent and floating thrombi and emboli in arteries, which appear as bright spots on imaging.
Radiographic features
The flashlight sign is described as a moving, very bright intraluminal focus of signal on B-flow 1.
Prac...
Article
Epidermal inclusion cyst
Epidermal inclusion cysts or epidermal cysts are common cutaneous lesions that represent proliferation of squamous epithelium within a confined space in the dermis or subdermis.
Terminology
These are occasionally termed sebaceous cysts, although this is a misnomer as the lesion does not origin...
Article
Three attenuation pattern
The three attenuation pattern or three density pattern was formerly known as the head cheese sign and refers to the presence of well-defined areas of decreased, normal, and increased attenuation on inspiratory CT 6.
Pathology
The resultant mosaic is due to lobular air-trapping with reflex hypo...
Article
Lambda sign (disambiguation)
There are two described lambda (λ) signs:
lambda sign (twin pregnancy)
lambda sign (sarcoidosis)
Article
Animal and animal produce inspired signs
Animal and animal produce inspired signs may sound a little silly, but the radiology literature is replete with such signs, some more fanciful than others.
Fish and marine life
cluster of black pearls sign
endosteal scalloping: medullary cavity masses, e.g. multiple myeloma
fish vertebra (al...
Article
Bird beak sign (disambiguation)
Bird beak sign is used in many contexts to denote a rapid tapering to a point, reminiscent of a bird's beak. Described bird beak signs include:
baby bird's beak sign (fetal TGA)
beak sign (arterial dissection)
beak sign (gallbladder)
beak sign (ovary)
beak sign (pyloric stenosis)
bird bea...
Article
Hot cross bun sign (pons)
The hot cross bun sign refers to the MRI appearance of the pons when T2 hyperintensity forms a cross on axial images, representing selective degeneration of transverse pontocerebellar tracts and median pontine raphe nuclei 1.
It has been described in a variety of neurodegenerative and other con...
Article
Cyclops lesion (knee)
The cyclops lesion, also known as localized anterior arthrofibrosis, is a painful anterior knee mass associated with loss of extension that arises as a complication of anterior cruciate ligament (ACL) reconstruction, although has rarely been reported in patients with ACL injuries that have not b...
Article
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...
Article
Susceptibility vessel sign
The susceptibility vessel sign is a radiological sign appreciated on susceptibility-sensitive MRI brain sequences that is described in patients with acute ischemic stroke. It correlates well with the hyperdense vessel sign (e.g. hyperdense MCA sign) that may be seen on CT brain, but is considere...
Article
Rigler sign (bowel)
The Rigler sign, also known as the double-wall sign, is a sign of pneumoperitoneum seen on an abdominal radiograph when gas is outlining both sides of the bowel wall, i.e. gas within the bowel's lumen and gas within the peritoneal cavity. It is seen with large amounts of pneumoperitoneum (>1000 ...
Article
Mickey Mouse sign (disambiguation)
In medical imaging, a Mickey Mouse sign or appearance has been given to imaging features that mimic Mickey Mouse when viewed from the front. It has been described in the following:
anencephaly 2
progressive supranuclear palsy 1
synonymously with a finger in glove sign
the flared shape of the...
Article
Snowstorm sign (extracapsular breast implant rupture)
The snowstorm sign on breast ultrasound imaging represents the presence of free silicone droplets mixed with breast parenchymal tissue causing characteristic homogeneously hyperechoic dense shadowing with dispersion of the ultrasound beam. It is considered the most reliable sign of extracapsular...
Article
Tangent sign of supraspinatus muscle belly atrophy
The tangent sign is useful in helping to quantify supraspinatus muscle belly atrophy with a positive sign implicated with a poorer outcome after supraspinatus tendon tear repair.
Measurement
On a sagittal oblique plane, a line is drawn between the upper surface of the scapular spine and the up...
Article
Shiny corner sign (ankylosing spondylitis)
The shiny corner sign is a spinal finding in ankylosing spondylitis, representing reactive sclerosis secondary to inflammatory erosions at the superior and inferior endplates (corners on lateral radiograph) of the vertebral bodies, which are known as Romanus lesions. Eventually, the vertebral bo...
Article
Romanus lesion (vertebral bodies)
The Romanus lesion represents an early finding in inflammatory spondyloarthropathies, such as ankylosing spondylitis and enteropathic arthritis, and appears as irregularity and erosion involving the anterior and posterior edges of the vertebral endplates 1. Healing response to these inflammatory...
Article
Suspected physical abuse
Suspected physical abuse (SPA), also known as non-accidental injury (NAI) or inflicted injury, in infants and young children represents both ethical and legal challenges to treating physicians.
Radiologists may be the first clinical staff to suspect non-accidental injuries when confronted with ...
Article
Cone-shaped cecum (differential)
A cone-shaped cecum refers to a loss of the normal rounded appearance of the cecum, 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
Ye...
Article
Steinstrasse
Steinstrasse [stīn′shtra-se] is the German word for "stone street", describing a possible complication of extracorporeal shock wave lithotripsy (ESWL) for urinary tract calculi, wherein a column of stone fragments forms that blocks the ureter.
Terminology
The term steinstrasse can equally, alb...
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