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.

747 results found
Article

Anteater nose sign (foot)

The anteater nose sign refers to an anterior tubular elongation of the superior calcaneus which approaches or overlaps the navicular on a lateral radiograph of the foot. This fancifully resembles the nose of an anteater and is indicative of calcaneonavicular coalition 1,2.  History and etymolog...
Article

Cockade sign (disambiguation)

There are several described cockade signs in radiology: cockade sign (intraosseous lipoma) cockade sign (aorto-left ventricular tunnel) 1 cockade sign (appendicitis) 2 cockade sign (hypertrophic pyloric stenosis) 3 cockade sign (GI tumours) 4
Article

Finger clubbing

Finger clubbing, also called "drumstick fingers", is a common clinical sign in patients with heart or lung disease. The term is used to describe an enlargement of the distal phalanges of the fingers, giving them a drumstick or club-like appearance.  Pathology The underlying pathogenesis of fin...
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

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

Elbow joint effusion

An elbow joint effusion is a key finding to recognise on an elbow radiograph and should be used as a trigger to search for a fracture.  Finding an effusion  Recognising an elbow joint effusion on lateral radiographs is an essential radiology skill. While the fluid itself is not discretely seen...
Article

White matter buckling sign

The white matter buckling sign is helpful in distinguishing an extra-axial mass from an intra-axial one, and represents the white matter projecting into gyri being compressed and displaced by the mass, even in the presence of oedema (which would usually expand gyri, if the mass were intra-axial)...
Article

Bunch of grapes sign (disambiguation)

Bunch of grapes sign refers to the ultrasound appearance of multiple cystic spaces or lesions and it has been described in a number of settings: within the uterus as a result of hydropic swelling of trophoblastic villi within a hydatidiform mole in bronchiectasis, where on a chest radiograph, ...
Article

Picture frame vertebral body

Picture frame vertebral body is a radiologic appearance in which the cortex of the vertebral body is thickened. This sign can be seen in patients with Paget disease.  It is a result of disorganised new cortical bone formation after excessive osteoclastic activity causes the resorption of normal...
Article

Calyceal crescent sign

The calyceal crescent sign (Dunbar crescents) refers to the early intravenous pyelogram (IVP) appearance of markedly dilated renal calyces. It is formed by early contrast opacification of the dilated collecting ducts and ducts of Bellini with the characteristic shape as a result of the associate...
Article

Ghon lesion

A Ghon lesion (sometimes called Ghon focus) represents a calcified tuberculous caseating granuloma (tuberculoma) and represents the sequelae of primary pulmonary tuberculosis infection. When associated with a calcified ipsilateral hilar node it is known as a Ranke complex. History and etymolog...
Article

Rat bite erosions (gout)

Rat (a.k.a. mouse) bite erosions are seen in gout and refer to punched out erosions with sclerotic and overhanging margins. 
Article

Bright rim sign in dysembryoplastic neuroepithelial tumours

The bright rim sign has been described in dysembryoplastic neuroepithelial tumours (DNET) and is seen, as the name so aptly describes, as a rim of high signal around the DNET on FLAIR sequences. The pathologic correlate of this sign is glioneural elements loosely packed at the margin of the tum...
Article

Starry sky appearance (ultrasound)

A starry sky appearance refers to a sonographic appearance of the liver parenchyma in which there are bright echogenic dots throughout a background of decreased liver parenchymal echogenicity. Although usually associated with acute hepatitis, this sign has been found to have poor sensitivity and...
Article

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, which presents as T2 hyperintensities. History and etymolog...
Article

Thurstan Holland fragment

The Thurstan Holland fragment also known as the Thurstan Holland sign is an eponymous radiological sign depicting a triangular portion of the metaphysis remaining with the epiphysis in a physeal fracture. This fragment is one of the tell-tale signs of a type 2 Salter-Harris fracture 1. History ...
Article

Mosaic attenuation pattern in lung

Mosaic attenuation is a descriptive term used in describing a patchwork of regions of differing pulmonary attenuation on CT imaging.  It is a non-specific finding, although is associated with the following: obstructive small airways disease: low attenuation regions are abnormal and reflect decr...
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

Banana sign (cerebellum)

The banana sign is one of the many notable fruit inspired signs. It is seen on axial imaging through the posterior fossa of the fetus and is associated with the Chiari II malformation. It describes the way the cerebellum is wrapped tightly around the brain stem as a result of spinal cord tether...
Article

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...
Article

Trident sign (CNS)

The trident sign describes the typical appearances of the pons in osmotic demyelination syndrome, whereby the symmetrical high T2/FLAIR signal abnormality centrally in the pons is shaped like a trident, the three-pronged spear of classical Greece 1. The trident is most commonly associated with t...
Article

Halo sign (chest)

The halo sign 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 pulmon...
Article

Pseudosubarachnoid haemorrhage

Pseudosubarachnoid haemorrhage is a sign related to apparent increased attenuation within the basal cisterns which simulates a true subarachnoid haemorrhage (SAH). Pathology Causes and associations The most common cause is cerebral oedema where there is a decrease in parenchymal attenuation a...
Article

Saddle pulmonary embolism

Saddle pulmonary embolism commonly refers to a large pulmonary embolism that straddles the bifurcation of the pulmonary trunk, extending into the left and right pulmonary arteries. If large enough, it can completely obstruct both left and right pulmonary arteries resulting in right heart failur...
Article

Abnormal bowel wall attenuation patterns

Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories: white enhancement gray enhancement water halo sign fat halo sign black attenuation The first three patterns are seen on contrast studies. White enhancement It is defined as uniform enhancement of th...
Article

Papilloedema

Papilloedema is an ophthalmoscopic diagnosis and refers to swelling of the optic disc. The MRI appearance relates to the dural anatomy of the optic nerve, which is continuous with the subarachnoid space, thereby allowing increased intracranial pressure (ICP) to be transmitted to the optic disc. ...
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 is ...
Article

Reversed halo sign (lungs)

Reversed halo sign, also known as the atoll sign, is defined as central ground-glass opacity surrounded by denser consolidation of crescentic (forming more than three-fourths of a circle) or ring (forming a complete circle) shape of at least 2 mm in thickness. It was initially described on high-...
Article

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...
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. For a general discussion of renal calculi please refer to nephrolithiasis. Epidemiology Stagh...
Article

Beak sign (arterial dissection)

The beak sign of arterial dissection is the acute angle formed at the edge of the false lumen in aortic dissection in axial cross-section. It is formed by the borders of the outer aortic wall and the intimal flap, and may be partially thrombosed (blunted beak). It is a reliable characteristic wh...
Article

Shading sign (endometrioma)

Shading sign is an MRI finding typically seen in an endometrioma. It may also be seen with some endometrioid tumours (e.g endometrioid carcinoma of the ovary) It helps to distinguish endometriomas from other blood-containing lesions (e.g. haemorrhagic corpus luteum cysts), with a sensitivity of...
Article

Stener lesion

Stener lesions are seen in the context of a torn ulnar collateral ligament of the thumb's metacarpophalangeal joint (gamekeeper's thumb).  Pathology Normally, the ulnar collateral ligament lies deep to the adductor pollicis tendon. A Stener lesion is characterised by slippage of the torn end o...
Article

Manta ray sign (bladder)

The manta ray sign is a radiographic appearance in bladder exstrophy. It describes wide midline separation of the pubic bones simulating the appearance of a manta ray swimming towards you 1. Differential diagnosis On a plain radiograph consider: open book pelvic injuries: the smooth arc of th...
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

Pine cone bladder

A pine cone bladder or christmas tree bladder is a cystogram appearance in which the bladder is elongated and pointed with thickened trabeculated wall. It is typically seen in severe neurogenic bladder with increased sphincter tone (detrusor sphincter dyssynergia) due to suprasacral lesions (abo...
Article

Hide-bound sign (bowel)

The hide-bound 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 hide-bound is u...
Article

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...
Article

Erlenmeyer flask deformity

Erlenmeyer flask deformity refers to a radiographic appearance typically on a femoral radiograph demonstrating relative constriction of the diaphysis and flaring of the metaphysis. Causes include marrow infiltration/expansion lysosomal storage disease Gaucher disease - osteopenia with Legg-C...
Article

Veiled right kidney sign

The veiled right kidney sign is a sonographic sign described in pneumoretroperitoneum, most commonly due to duodenal perforation. It refers to the appearance of the right kidney on transabdominal ultrasound 1-4. On ultrasound, there is difficulty in obtaining images of the right kidney due to i...
Article

Scalpel sign (spinal cord)

The scalpel sign has been recently described in dorsal thoracic arachnoid web on sagittal MRI spine studies. It relates to focal distortion of the thoracic cord, appearing anteriorly displaced. The enlarged dorsal CSF space mimics the profile of a surgical scalpel. It is helpful in distinguishi...
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

Fat stranding (summary)

This is a basic article for medical students and other non-radiologists Fat stranding is a sign that is seen on CT. It describes the change in attenuation of fat around an inflamed structure and is a very helpful signpost for intra-abdominal pathology. Reference article This is a summary arti...
Article

Perinephric stranding

Perinephric stranding refers to the appearance of oedema within the fat of the perirenal space on CT or MRI. While a degree of symmetric bilateral perinephric stranding is common, particularly in the elderly, asymmetric or unilateral perinephric stranding is an important sign of renal inflammati...
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. Incidence Steinstrasse usually develops 1 day to 3...
Article

Popcorn calcification within the breast

Popcorn calcification in the breast is the classical description for the calcification seen in involuting fibroadenomas which, as the name suggests, has a popcorn-like appearance.  Pathology A fibroadenoma in the long run may degenerate and calcify. Initially there are a few punctate periphera...
Article

Striated nephrogram

Striated nephrogram is a descriptive term indicating an appearance of alternating linear bands of high and low attenuation in a radial pattern extending through the corticomedullary layers of the kidney on iodine-based intravenous contrast enhanced imaging. It is important to know that a simila...
Article

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 differential for a Kirklin sign includes: gastric tumour gastric carcinoma oesophageal carcinoma gastrointestinal stromal tumour (GIST...
Article

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. 
Article

Honeycombing (lungs)

Honeycombing is a CT imaging descriptor referring to clustered cystic air spaces (between 3-10 mm in diameter but occasionally as large as 2.5 cm) which are usually subpleural and basal in distribution. They can be subdivided into: microcystic honeycombing: macrocystic honeycombing The walls ...
Article

Telltale triangle sign

The telltale triangle sign, also known as the triangle sign or telltale triangle, is a radiographic sign seen on plain abdominal radiograph that signifies presence of pneumoperitoneum 1. It describes the appearance of a radiolucent triangle of gas formed between three loops of bowel or between t...
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.
Article

Panda sign (midbrain)

The panda sign in neuroimaging refers to the appearance of the midbrain, when the red nucleus and substantia nigra are surrounded by high T2 signal. It is classically seen in Wilson disease, although whenever the white matter is diffusely abnormal in the region a similar appearance will be perc...
Article

Shepherd crook deformity

A shepherd crook deformity refers to a coxa varus angulation of the proximal femur, classically seen in femoral involvement by fibrous dysplasia, although may be seen in other disorders such as Paget disease of bone and osteogenesis imperfecta. History and etymology The shape of the proximal f...
Article

Absent nasal bone

In a fetal sonographic assessment, an absent nasal bone is a feature which can sometimes be used as an adjunctive marker for fetal aneuploidy. Radiographic assessment Antenatal ultrasound It is assessed on a midline sagittal view. In this section, the nasal bone is often seen as a bright echo...
Article

Parrot beak meniscal tear

Parrot beak meniscal tears are a type of oblique meniscal tear which is connected in one plane and displaced in the other plane. Its appearance on axial images is curved like a crescent and is likened to that of a parrot's beak. The tear gap has a curved V-shape.  Some authors advise that the t...
Article

Vegetable and plant inspired signs

There are many signs in radiology which are vegetable- and plant-inspired, they include: Unprocessed produce celery stalk anterior cruciate ligament: ACL mucoid degeneration celery stalk metaphysis: osteopathia striata and congenital rubella infection Christmas tree intestinal atresia cocon...
Article

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...
Article

Extracranial brain herniation

Extracranial brain herniation refers to herniation of brain tissue external to the calvaria through a skull bone defect, which may be post-traumatic or post-surgical. Unlike encephaloceles, brain herniation is not surrounded by the meninges.  The herniated brain tissue requires surgical reducti...
Article

Erased charcoal sign (prostate cancer)

The erased charcoal sign usually describes the typical lenticular or water drop lesion of a homogeneous low T2WI focal prostate cancer with an ill-defined border within the transition zone.
Article

Abnormally eccentric gestational sac

An eccentrically-located gestational sac towards the fundus of the uterus is the normal sonographic appearance; however an abnormally eccentric gestational sac on ultrasound may be apparent due to a number of causes They include interstitial ectopic pregnancy 1 normally implanted pregnancy in...
Article

Raindrop skull

The appearance of multiple, well-defined lytic lesions (punched out lesions) of various size scattered throughout the skull constitutes the raindrop skull appearance of multiple myeloma. This term is applied as an analogy to rain hitting a surface and splashing, where it leaves a random pattern ...
Article

Butterfly vertebra

Butterfly vertebra is a type of vertebral anomaly that results from the failure of fusion of the lateral halves of the vertebral body because of persistent notochordal tissue between them. Pathology Associations an anterior spina bifida, with or without an anterior meningocele can be part of...
Article

Rigler triad

Rigler triad consists of three findings seen in gallstone ileus: pneumobilia small bowel obstruction ectopic gallstone, usually in the right iliac fossa History and etymology It is named after Leo George Rigler, American radiologist (1896-1979) 1. Practical points Rigler triad should not ...
Article

Accordion sign (colon)

The accordion sign (also known as concertina sign) is seen on CT examinations of the abdomen and refers to the similarity between the thickened oedematous wall of pseudomembranous colitis and the folds of an accordion. This appearance is the result of hyperaemic enhancing mucosa stretched over m...
Article

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 dislocation 1,2,4. The cro...
Article

Trident acetabulum

Trident acetabulum is an appearance which can be seen in several skeletal dysplasias 1. It is characterised by small bony spurs at the medial and lateral acetabular margins with a more subtle central spur, resembling a trident, the three-pronged spear of classical Greece 1. The trident is most ...
Article

Weapon and munition inspired signs

Weapon and munition inspired signs include the following with their corresponding pathologic conditions: bayonet deformity Turner syndrome chondrodysplasia bullet-shaped vertebra mucopolysaccharidosis achondroplasia cannonball metastases metastases from renal cell carcinoma dagger sign ...
Article

Trident hand

A trident hand is a description where the hands are short with stubby fingers, with a separation between the middle and ring fingers.  The appearance mimics a trident, the three-pronged spear of classical Greece. The trident is most commonly associated with the sea god Poseidon in Greek mytholo...
Article

Inanimate object inspired signs

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

Telephone receiver deformity

A telephone receiver deformity is a characteristic bowing of the shaft of the long bones, usually the humeri or femora, seen in thanatophoric dysplasia.
Article

Bulging fissure sign

The bulging fissure sign refers to lobar consolidation where the affected portion of the lung is expanded causing displacement of the adjacent fissure. Any type of pneumonia or space-occupying process can lead to bulging (sagging) fissure sign. Classically, it has been described in upper right l...
Article

Boomerang sign (splenium)

The boomerang sign refers to a boomerang-shaped region of cytotoxic oedema in the splenium of the corpus callosum typically seen in cytotoxic lesions of the corpus callosum (CLOCCs) 1-4.  See also boomerang sign in peroneus brevis split syndrome boomerang sign in horizontal meniscal flap tear
Article

Air crescent sign (lung)

An air crescent sign describes the crescent of air that can be seen in invasive aspergillosis, semi-invasive aspergillosis or other processes that cause pulmonary necrosis. It usually heralds recovery and is the result of increased granulocyte activity. In angioinvasive fungal infection, the no...
Article

Geyser sign (shoulder)

The geyser sign may occur in some cases of long-standing rotator cuff tear and advanced degenerative change of the shoulder.  Clinical presentation It may present as a pseudotumour above the AC joint. Pathology Chronic rotator cuff degenerative change and full-thickness tearing leads to inst...
Article

Zebra spleen

Zebra spleen, also referred to as psychedelic spleen or more correctly inhomogeneous splenic enhancement refers to the transient heterogeneous parenchymal enhancement of the spleen during the arterial or early portal venous phases of contrast enhancement in CT, MRI, or ultrasound imaging. It is...
Article

Zebra stripe sign (bones)

The zebra stripe sign occurs where children with osteogenesis imperfecta have been treated with cyclical bisphosphonate therapy, e.g. pamidronate. When the drug is delivered in cycles, dense bone is formed while treatment is being given. This results in dense stripes across the metaphyses of bon...
Article

Venus necklace

A Venus necklace is a term almost never used, but for the sake of completeness is included here. It is used by some authors 1 to describe a series of T2 hyperintense lesions on the inferior surface of the corpus callosum in the midline (callososeptal interface), most frequently seen in multiple ...
Article

Vacuum phenomenon in shoulder

Vacuum phenomenon in the shoulder refers to the presence of intra-articular gas in the shoulder joint. It is a very common occurrence, particularly in external rotation. This can cause circular or linear areas of low signal intensity on GRE MR images of the shoulder obtained with external rotati...
Article

Upper T sign

The upper T sign is one of the features useful in identifying the central sulcus of the cerebral cortex on cross-sectional imaging. It relies on identifying the superior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulc...
Article

Upper lobe pulmonary venous diversion

Upper lobe pulmonary venous diversion (cephalisation) reflects elevation of left atrial pressure and can occur with pulmonary oedema. It produces stag-antler's sign on a frontal chest x-ray. The normal left atrial pressure is 5-10 mmHg. An elevation of left atrial pressure to 10-15 mmHg will re...
Article

Two-slice-touch rule (knee MRI)

The two-slice-touch rule is a sign on MRI of the knee used to increase the sensitivity of diagnosing meniscal tears. This rule states a meniscal tear is present if abnormal findings are present on two or more images - these do not have to be contiguous, e.g. can occur on sagittal and coronal sl...
Article

Stack of coins sign (bowel)

Stack of coins sign refers to the appearance of small bowel folds that are smoothly and uniformly thickened 1. The margins between the folds are sharply delineated and the arrangement of clearly demarcated parallel folds is likened to a stack of coins or a picket fence. This sign is distinct fro...
Article

Rigler sign

The Rigler sign, also known as the double wall sign, is seen on a radiograph of the abdomen when the air is present on both sides of the intestine, i.e. when there is air on both the luminal and peritoneal side of the bowel wall. Pneumoperitoneum may be a result of perforation or, recent instru...
Article

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 occasionall...
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 surrounding dark zones representing adjacent scleroti...
Article

Tram-track sign (brain)

Tram-track sign in the brain refers to the parallel calcification of the cortex in patients with Sturge-Weber syndrome 1.  It should not be confused with other tram-track signs elsewhere in the body. 
Article

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

Empty thecal sac sign

The empty thecal sac sign or empty sac sign is when the thecal sac appears empty on MRI of the lumbar spine, best seen on T2-weighted images. If the empty thecal sac sign is present, a diagnosis of adhesive arachnoiditis can be made.​ Radiographic features MRI There is usually no gadolinium c...
Article

Sulcal effacement

Sulcal effacement is a local secondary sign of mass effect in the cranium. Any lesion exerting mass effect on brain parenchyma can push adjacent gyri together, thereby displacing the CSF from the sulci. It is greatest at the site where the cause of the mass effect is located (e.g. tumour, haemo...
Article

État criblé

État criblé, also known as status cribrosum, is a term that describes the diffusely widened perivascular spaces (Virchow-Robin spaces) in the basal ganglia, especially in the corpus striatum on MRI. It is usually symmetrical, with the perivascular spaces showing CSF signal and without diffusion ...
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...
Article

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 ...

Updating… Please wait.
Loadinganimation

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.