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.
1,140 results found
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
Tubal ring sign
The tubal ring sign, also referred to as a bagel sign or blob sign, is one of the ultrasound signs of a tubal ectopic pregnancy. It comprises an echogenic ring that surrounds an unruptured ectopic pregnancy. It is said to have a 95% positive predictive value (PPV) for ectopic pregnancy.
Differe...
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Rim sign (osteonecrosis)
A rim sign can be seen in osteonecrosis and comprises a high T2 or intermediate T1 signal line sandwiched between two low signal lines, and represents fluid between the sclerotic borders of an osteochondral fragment, and implies instability (stage III).
This rim sign should not be confused with...
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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Bullet-shaped vertebra
Bullet-shaped vertebra, also known as ovoid vertebra, refers to the anterior beaking of the vertebral body.
It is seen in the following conditions:
mucopolysaccharidosis (Morquio disease, Hurler disease)
achondroplasia
congenital hypothyroidism
progressive pseudorheumatoid dysplasia 4
Wils...
Article
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...
Article
Rovsing sign
Rovsing sign is commonly used to describe pain elicited in the right iliac fossa on deep palpation of the left iliac fossa.
It is used in clinical examination to detect peritoneal irritation in the right iliac fossa, most frequently associated with acute appendicitis. Most teaching erroneously...
Article
Cerebral cortical restricted diffusion
Cerebral cortical restricted diffusion, also known as gyriform restricted diffusion, cortical ribboning or cortical ribbon sign, refers to curvilinear hyperintense signal involving the cerebral cortex on DWI images with a corresponding low signal on ADC images.
Causes include the following diso...
Article
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...
Article
Funnel trachea
Funnel trachea is a colloquialism for a congenital long-segment intrathoracic tracheal stenosis.
The diameter of the trachea immediately below the cricoid is normal, and becomes progressively more stenotic caudally. The posterior, membranous portion of the trachea may be partially or completel...
Article
Celery stalk metaphysis
Celery stalk metaphysis refers to a plain film appearance of the metaphyses in a number of conditions characterized by longitudinally aligned linear bands of sclerosis. They are seen in:
congenital infections
congenital rubella
congenital syphilis
congenital cytomegalovirus (CMV)
osteopathi...
Article
Corkscrew sign (midgut volvulus)
The corkscrew sign describes the spiral appearance of the distal duodenum and proximal jejunum seen in midgut volvulus 1.
In patients with malrotation and volvulus, the distal duodenum and proximal jejunum do not cross the midline and instead pass in an inferior direction. These loops twist on ...
Article
Mother in law sign
The mother in law sign is perhaps uncharitably (depends on the mother in law I suppose) used to describe lesions that enhance early during the arterial phase and remain opacified well after the venous phase. The joke is that a mother in law comes early and stays late.
It is most frequently equ...
Article
Spaghetti sign (bladder)
The spaghetti sign may be seen in upper urinary tract bleeding.
It refers to the presence of a linear worm- or spaghetti-like filling defect within a contrast-opacified bladder 1,2. This linear filling defect represents blood clot extruded from the ureter and thereby molded into a tubular shape...
Article
Rosary sign (gallbladder)
The rosary sign is a CT finding in adenomyomatosis of the gallbladder. It is formed by the enhanced proliferative mucosal epithelium, with the intramural diverticula surrounded by the unenhanced hypertrophied muscle coat of the gallbladder. The rosary sign is similar to the pearl necklace sign.
Article
Floating head appearance
A floating head appearance refers to imaging features observed typically on antenatal ultrasound with certain skeletal dysplasias such as achondrogenesis.
Against the background of a poorly-mineralized spine, a normally ossified skull is seen giving an impression of a floating head.
Article
Cartilage interface sign
Cartilage interface sign, also referred to as double cortex sign, refers to the sonographic presence of a thin markedly hyperechoic line at the interface between the normally hypoechoic hyaline articular cartilage of the humeral head and an abnormally hypoechoic supraspinatus tendon. This arises...
Article
Staghorn calculus (kidney)
Staghorn calculi, also sometimes called coral calculi, are renal calculi that obtain their characteristic shape by forming a cast of the renal pelvis and calyces, thus resembling the horns of a stag. They refer to struvite calculi involving the renal pelvis and extending into at least two calyce...
Article
Spalding sign (fetal demise)
The Spalding sign refers to the overlapping of the fetal skull bones caused by collapse of the fetal brain. It appears usually a week or more after fetal death in utero.
This finding was originally described by Alfred Baker Spalding (1874-1942), an American obstetrician 2, on abdominal radiogr...
Article
Sergeant stripes sign (cerebellum)
The sergeant stripes sign refers to the oblique direction of the cerebellar tonsillar folia a feature sometimes visible in cases of Chiari I malformation on sagittal imaging. It is unclear which insignia this is meant to represent as the direction of the chevrons depends on nationality. For exam...
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