Wackenheims line (also known as the clivus canal line or basilar line) is formed by drawing a line along the clivus and extending it inferiorly to the upper cervical canal.
Normally the tip of the dens is ventral and tangential to this line. In basilar invagination odontoid process transects th...
The WAGR syndrome stands for:
Wilms tumours (greatly increased risk)
Occurs from a mutation related to chromosome 11p13 3 which is in close proximity to WT1 gene.
A Wagstaffe-Le Forte fracture refers to an avulsion fracture of the medial aspect of the distal fibula due to avulsion of the anterior talofibular ligament attachment.
lower extremity fractures
Waldenström sign is the increased distance between the pelvic tear drop and the femoral head. It is a non-specific sign of hip joint effusion.
>11 mm total distance or >2 mm difference compared to contralateral hip 1, 2
measured between the lateral aspect of ...
Waldenström's macroglobulinaemia (WM), (previously also known as lymphoplasmacytic lymphoma (LPL)), is a type of B-cell lymphoma. It is a rare condition, accounting for only 1% of all lymphoproliferative disorders.
Recent publications classify Waldenström's macroglobulinaemia as an lymphoplasm...
Waldeyer's ring is a ring of lymphoid tissue located in the nasopharynx and oropharynx at the entrance to the aerodigestive tract.
The structures composing this ring are:
palatine tonsils (also called the faucial tonsils)
adenoid tonsils (nasopharyngeal tonsils)
the lateral ba...
Walker-Warburg syndrome (WWS), sometimes known as HARDE syndrome, is an extremely rare lethal form of congenital muscular dystrophy. It is primarily characterised by:
fetal hydrocephalus: almost always present
neuronal migrational anomalies: agyria (cobblestone lissencephaly / lissencephaly ty...
The walking man sign is seen on lateral chest radiograph and is a sign of left atrial enlargement. It results from posterior displacement of the left main bronchus such that it no longer overlaps the right bronchus. The left and right bronchus thus appear as an inverted 'V', mimicking the legs o...
The wall-echo-shadow sign (also known as WES sign) is an ultrasonographic finding within the gallbladder fossa referring to the appearance of a "wall-echo-shadow"
a curvilinear hyperechogenic line representing the gallbladder wall
a thin hypoechoic space representing a small amount of bile
Walled-off pancreatic necrosis (WOPN) is a late complication of acute pancreatitis, although it can occur in chronic pancreatitis or as a result of pancreatic trauma. Differentiation of WOPN from pancreatic pseudocyst is essential because management differs. WOPN may need aggressive treatment to...
Wallerian degeneration (WaD) is the process of antegrade degeneration of the axons and their accompanying myelin sheaths following proximal axonal or neuronal cell body lesions. It may result following neuronal loss due to cerebral infarction, trauma, necrosis, focal demyelination or haemorrhage...
Wandering spleen is a rare condition in which the spleen migrates from its usual anatomical position, commonly to the lower abdomen or pelvis.
Wandering spleen is rare, with a reported incidence of <0.5%.
Diagnosis is most commonly made between ages 20 and 40 and is more common i...
Ward triangle refers to a radiolucent area between principle compressive, secondary compressive and primary tensile trabeculae in the neck of femur.
It should be differentiated from Babcock triangle.
Wartenberg syndrome also known as cheiralgia paresthetica is due to compression of superficial branch of the radial nerve in the distal forearm. It can be secondary to tight watch band or handcuffs, compression from distal radius fracture or idiopathic.
Patients present ...
Warthin tumours (or papillary cystadenoma lymphomatosum) are a benign, sharply demarcated tumour of the salivary- lymphoid origin most commonly arising from parotid gland tail. They are bilateral or multifocal in up to 20% of cases, and are the most common neoplastic cause of multiple solid paro...
The wasp-waist sign is a radiographic appearance seen in patients with Klippel Feil syndrome. It results from fusion of the vertebral bodies such that the anteroposterior diameter at the level of the affected discovertebral joint is smaller than the diameter at the superior and inferior limits o...
Watchman device is a permanent left atrial appendage closure device, which is percutaneously implanted to prevent embolisation of thrombus from the appendage into systemic circulation in cases atrial fibrillation. It is used when there is contraindication to anticoagulation or high risk of lifel...
The water bottle sign or configuration refers to the shape of the cardiac silhouette on erect frontal chest x-rays in patients who have a very large pericardial effusion. Typically the effusion has accumulated over many weeks to months (e.g. in patients with malignancy) and the pericardium has g...
The water-lily sign is seen in hydatid infections when there is detachment of the endocyst membrane which results in floating membranes within the pericyst that mimic the appearance of a water lily.
It is classically described on plain radiographs (mainly chest X-ray) when the collapsed membran...
The water siphon test may be performed as part of a barium swallow to assess for gastro-oesophageal reflux in a hiatal hernia. It is performed in the supine RPO position with the patient drinking water continuously. The test is said to be positive if there is visible barium reflux in the oesopha...
Waterhouse-Friderichsen syndrome is characterised by adrenal insufficiency that results from atraumatic adrenal haemorrhage in consequence of septicaemia.
Waterhouse-Friderichsen syndrome is due to septicaemia and common infective agents include 5:
meningococcus: traditionally desc...
Watershed cerebral infarctions, also known as border zone infarcts, occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus most vulnerable to reductions in perfusion.
Watershed cerebral infarction account for 5-10% of ...
A Waterston shunt is a form of palliative surgery performed in patients with tetralogy of Fallot prior to the ability to repair the defect. It consists of a shunt formed between the ascending aorta and the right pulmonary artery.
This does not relieve the right ventricular outflow obstruction, ...
The wave sign refers to the indentation of the normal thymus in young children by the ribs, resulting in a wavy border.
Weapons and munition inspired signs include the following with their corresponding pathologic conditions:
metastases from renal cell carcinoma
Weaver syndrome (WS) is a rare congenital disorder.
increased birth weight: fetal macrosomia
accelerated osseous maturation: increased bone age
typical facial features
The Weber ankle fracture classification (sometimes Danis-Weber) is a simple system for classification of lateral malleolar fractures, relating to the level of the fracture in relation to the ankle joint. It has a role in determining treatment.
below the level of the tal...
Weber syndrome is a midbrain stroke syndrome that involves the fascicles of the oculomotor nerve resulting in an ipsilateral CN III palsy and contralateral hemiplegia or hemiparesis.
Using imaging alone, it is difficult to distinguish Weber from Benedikt syndrome, unless clear involvement of th...
Weber-Christian disease or Pfeifer-Weber-Christian disease or idiopathic relapsing febrile nodular non-suppurative panniculitis was initially defined as a rare inflammatory disorder of unknown aetiology affecting subcutaneous adipose tissue inter alia 1.
However, the understanding of lobular pa...
Wedge fractures are hyperflexion injuries to the vertebral body resulting from axial loading. Most commonly affecting the anterior aspect, wedge fractures are considered a single-column (i.e. stable) fracture.
Less commonly wedge fractures refer to a subtype of tibial plateau fractures. This a...
The Weigert-Meyer law describes the relationship of the upper and lower renal moieties in duplicated collecting systems to their drainage inferiorly.
With duplex kidney and complete ureteral duplication, the upper renal and lower renal moiety have their own ureters with each ...
Reporting a weightbearing foot series can be a daunting process if you are inexperienced and often results in the films being left for somebody else to report. This article attempts to demystify the whole process by providing a structured approach to their reporting.
The weightbearing lateral foot radiograph is important in the assessment of foot alignment and the diagnosis of abnormalities that cause malalignment and foot pain. Nonweightbearing views (e.g. oblique foot radiograph) are inadequate for the assessment of alignment because the bones of the feet ...
Certain well-defined breast cancers tend lack the characteristic spiculation and can give false reassurance of more benign entities on both ultrasound and mammography. These include:
certain high grade invasive ductal carcinomas: not enough time for a desmoplastic reaction to form spiculation
Werner syndrome is a progeroid rare autosomal recessive condition attributed to chromosome 8. It should not to be confused with similarly sounding Wermer syndrome.
Werner syndrome is characterised by
scleroderma-like skin changes such ...
Wernicke's area (Brodmann area 22) is an area of the posterior temporal lobe in the dominant hemisphere concerned with the receptive components of speech.
Wernicke's area is located in the superior temporal gyrus, posterior to the posterior commissure line.
It is boun...
Wernicke encephalopathy, also referred as Wernicke-Korsakoff syndrome, is due to thiamine (vitamin B1) deficiency, and is typically seen in alcoholics.
On imaging, it is commonly seen on MRI as areas of symmetrical increased T2/FLAIR signal involving the mamillary bodies, dorsomedial thalami, t...
Westermark sign is a sign of pulmonary embolus (PE) seen on chest radiographs.
Along with Fleishner sign and Hampton hump, it makes one of the three described signs of pulmonary embolus on chest radiographs.
In one study (PIOPED) this sign was present on ~10% of chest x-rays of pati...
The WFNS grading system (World Federation of Neurosurgical Societies) uses the Glasgow Coma Scale and presence of focal neurological deficits to grade the severity of subarachnoid haemorrhage. This grading system was proposed in 1988, and this is one of the accepted systems (although not conside...
Wharton jelly refers to the gelatinous substance within the umbilical cord.
Wharton jelly is derived from extra-embryonic mesoderm and is largely made up of mucopolysaccharides (hyaluronic acid and chondroitin sulfate) while containing smaller amounts of fibroblasts and macrophag...
So what should the perfect case look like? Over time the quality of contributions to Radiopaedia.org is ever growing and a consensus is emerging as to the make up of a perfect case. For a general set if instructions refer to our case publishing guidelines.
Below are some points to consider when...
Radiopaedia.org is more than just a website. It is the front end of a community whose aim is to develop the best researched, most comprehensive and most accessible online radiology reference site... read more.
Radiopaedia.org IS an opportunity to contribute to a project which will hopefully be...
We are attempting to create the best radiology resource which is no small task and is going to take the combined efforts of many many people. These are a couple of thoughts about what Radiopaedia.org is NOT:
Radiopaedia.org is NOT a place to cut and paste content from textbooks, articles or oth...
This sign is seen in USG of patient with the hepatic candidiasis and described as central hypoechoic area (necrosis containing fungi) surrounded by an echogenic zone (inflammatory cells).
Differs from bull’s-eye sign for reverse echogeniticity, as it consists a central echogenic nidus surrounde...
Making a decision about when to use bold in an article is important since we know that adding bold and italics to articles reduces its readability.
There are very few examples of when to use bold in an article on Radiopaedia.org and as such, if you're unsure, it's probably worthwhile not using ...
Making a decision about when to use italics in Radiopaedia.org articles is important because the addition of bold and italic words in prose actually reduces readability.
In literature, italics can be used for a number of things, including titles of works. However, in order to keep things simple...
Whipple disease is a rare infectious multisystem disorder caused by the actinobacteria Tropheryma whipplei.
The incidence of Whipple disease is not truly known, one Swiss study estimated it at approximately 1 per 1.5 million per year 7.
The peak age for presentation is in the fif...
Gastrointestinal manifestations are a key component of Whipple disease (a.k.a. intestinal lipodystrophy).
Extensive infiltration of lamina propria with large macrophages infected by intracellular Tropheryma whipplei causes marked swelling of intestinal villi and thickened irregular m...
Neurological manifestations of Whipple disease are rare. Whipple's disease can also appear as a primary neurological disorder in rare cases. It is rarely incidentally found as a differential diagnosis in patients with a progressive neurological deficit.
It has been suggested that neurological i...
Thoraco-pulmonary manifestations of Whipple disease are uncommon and may result in later course of disease.
Lung involvement is seen in 35-60% of patients with gastrointestinal whipple disease. Males are affected eight times than of females.
Grossly there are areas of ...
The Whipple procedure (or partial pancreaticoduodenectomy) is considered the definitive surgical operation to resect carcinoma in the head of the pancreas, periampullary carcinoma, or duodenal carcinoma 1.
In the procedure, the head of the pancreas and adjacent duodenum is resected. The gallbla...
Whipple triad is the clinical presentation of pancreatic insulinomas and consists of:
fasting hypoglycemia (<50 mg/dl)
symptoms of hypoglycemia
immediate relief of symptoms after the administration of IV glucose
History and etymology
As a good piece of trivia, one would suspect that Whipple...
The whirlpool sign, also known as the whirl sign, is seen when a structure twists upon itself. It is most commonly described in the abdomen where bowel rotates around its mesentery, with mesenteric vessels creating the whirls. It can also be seen in ovarian torsion.
Whirlpool sign: mesenteric
White cerebellum sign, also called reversal sign or dense cerebellum sign, is encountered when there is a diffuse decrease in density of the supratentorial brain parenchyma, with relatively increased attenuation of the thalami, brainstem and cerebellum. This sign indicates irreversible brain dam...
The white coat effect (WCE), not to be confused with white coat hypertension, is a measure of change that is commonly defined as the difference between in-clinic and out-of-clinic blood pressure readings 1,2.
Alternatively, the white coat effect can be defined as the increase in the arterial b...
White coat hypertension (abbreviated alternatively as WCH or WCHT), not to be confused with the white coat effect (WCE), is commonly defined as typical in-clinic blood pressure (BP) measurements of 140/90 mm Hg or more in the presence of multiple daytime out-of-clinic home or ambulatory BP readi...
White epidermoids are a rare type of epidermoid cyst that do not follow the usual near-CSF density and signal intensity on CT and MR respectively. To make matters worse the literature uses the term inconsistently, although generally the 'white' refers to the T1 weighted imaging appearance.
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)...
White matter changes in HIV have overlapping appearances and varied in aetiology. These can be divided into:
primary effects of HIV
metabolic and nutritional disorders
Primary effects of HIV
White matter diseases are a group of conditions that predominantly or significantly affect the white matter of the brain. They comprise a vast heterogeneous group and have a variety of appearances and presentations. They cause disease by altering the process of normal myelination.
White matter tracts, also known as white matter fibres, are classified into three categories:
tracts connecting the cortex with other area in the CNS, e.g. deep nuclei, brainstem, cerebellum or spine
may be efferent (motor) or afferent tracts (sensory)
white matter tracts t...
The white pyramid sign refers to the CT appearance of the medullary pyramids of the kidney which can be seen normally on unenhanced CT scans as high-attenuation triangular structures.
Bilateral high-attenuation renal pyramids are an occasional incidental normal finding. In contrast, unilatera...
The World Health Organisation classifies anal canal neoplasms into intraepithelial neoplasms and invasive neoplasms which are further divided to epithelial and non-epithelial tumours and secondary lesions:
squamous cell carcinoma of anal canal
adenocarcinoma of anal canal
The WHO classification of anal margin tumours or perianal skin tumours is:
Bowen disease (precursor of squamous cell carcinoma)
Paget's disease (precursor of adenocarcinoma)
squamous cell carcinoma
basal cell carcinoma
The WHO classification of CNS tumours is the most widely accepted system for classifying CNS tumours and was based on the histological characteristics of the tumour. Although the most recent version of the 'blue book' is the 4th edition from 2007, an update has been released in 2016 3, which sho...
The WHO classification scheme for thymic epithelial tumours is one of many classifications systems for thymoma and related tumours, and classifies them according to histology:
spindle cell thymoma
type ab: mixed thymoma
type b1: lymphocyte rich
WHO (World Health Organisation) grading of CNS tumours is based on histological characteristics such as cellularity, mitotic activity, pleomorphism, necrosis, and endothelial proliferation (neoangiogenesis). It is used in the WHO classification of CNS tumours.
It should be noted that at the ti...
The WHO grading system is the most widely used system for grading diffuse astrocytomas (at the time of writing i.e. mid 2016), and is an adaptation of the now superseded St Anne-Mayo grading system (also known as the Daumas-Duport grading system).
Grade I is reserved for localised astrocytom...
Benign renal tumours were histologically classified according to the WHO in 2004 as follows 1:
Renal cell tumours
renal papillary adenoma - renal adenoma
metanephric adenoma of kidney
metanephric adenofibroma of kidney
metanephric stromal tumour of kid...
The WHO histological classification is a detailed classification of tumours of the uterine cervix. It is as follows
squamous tumours and precursors
squamous cell carcinoma, not otherwise specified - 8070/3
keratinizing - 8071/3
non-keratinizing - 8072/3
basaloid - 8083/3...
Radiopaedia.org is more than just an amazing collaborative resource, it is also the perfect place to keep your case library.
Here are a few reasons why you should upload your cases to Radiopaedia.org:
unlimited storage capacity for your cases
support for scrollable stacks,...
Wiberg classification is a system used to describe the shape of the patella based mainly on the asymmetry between the patellar medial and lateral facets on axial views of the patella. Increasing number type indicates a larger degree of asymmetry.
Wiberg type 1 or a
A widened intercondylar notch on knee radiographs is a sign associated with:
juvenile rheumatoid arthritis
The interpedicular (IP) distance which is the distance measured between the pedicles on frontal / coronal imaging can be widened in a number of situations.
conditions that can cause dural ectasia (can potentially cause widening)
Widening of the presacral space is one of the diagnostic indicators of the diseases involving pelvic pathology and rectal involvement. It is ideally measured on barium studies at the level of S3/4 disc level on lateral radiographs and the normal value of the presacral space is <15 mm in adults....
A frontal hairline projection is known as the Widow's peak hair anomaly.
Named after a headdress worn by some widows in the western countries
It is purported that the periorbital fields of hairless region or hairgrowth suppression are widely spaced or the hairless regions...
Wildervanck syndrome, also known as cervico-ocular-acoustic dysplasia, consists of the triad of:
congenital ossicular anomalies: usually diffuse ossicular ankylosis and sensorineural deafness.
Duane's retraction syndrome: an ocular motility disturbance due to fibrosis of...
Wilhelm Conrad Roentgen was a German physicist born on 27th March 1845. On the 8th of November 1895, he was the first to detect X-rays/Roentgen rays.
Schooling and academic career
Wilhelm attended the primary and secondary school run by of Martinus Hemmann van Doom in the town of Apeldoomn, Ho...
Williams syndrome (WS) is characterised by some or all or the following features:
craniofacial dysmorphism (e.g. elfin facies)
short stature (50% of cases)
mild to moderate mental retardation
supravalvular aortic stenosis 2
pulmonary artery stenosis 3
Williams-Campbell syndrome (WCS) is a rare form of congenital cystic bronchiectasis, in which distal bronchial cartilage is defective.
It is thought to result from a deficiency of cartilage formation in the 4th to 6th order segmental bronchi.
Wilms tumour, also known as nephroblastoma, is a malignant paediatric renal tumour.
Wilms tumours are the most common paediatic renal mass, accounting for over 85% of cases 1,8 and accounts for 6% of all childhood cancers 2. It typically occurs in early childhood (1-11 years) with...
Wilms' tumour staging is largely anatomical and relates to the invasion and spread of the tumour. Where there is invasion or metastasises, prognosis is poorer. Wilms tumour, is one of the more common childhood malignancies.
confined to kidney
complete resection possible
Wilson disease, also known as hepatolenticular degeneration, is a rare autosomal recessive disorder of copper metabolism affecting multiple systems.
Wilson disease is commonly found in Japan. It affects 1 in 30,000-40,000 individuals 12.
Wilson disease, also known as hepatolenticular degeneration, is a multisystem disease, where there is an accumulation of copper.
This article aims to discuss the central nervous system manifestations of this condition, for a broad view on the condition, please refer to the article on Wilson dis...
Hepatobiliary manifestations of Wilson disease vary largely from fatty changes to cirrhosis and occasionally fulminant hepatic necrosis. They result from accumulation of copper in the liver.
For a general discussion of the underlying condition, please refer to the article Wilson disease.
Wilson disease, also known as hepatolenticular degeneration, is a multisystem disease, which rarely has musculoskeletal manifestations when there is accumulation of copper in the articular cartilage.
Reported manifestations include 1,2,3
Wilson Mikity syndrome (WMS) refers to chronic lung disease in premature infants, characterized by early development of cystic interstitial emphysema (PIE). This is now sometimes considered as part of the spectrum of bronchopulmonary dysplasia.
chronic pulmonary insufficiency of prema...
Wimberger ring sign refers to a circular calcification surrounding the osteoporotic epiphyseal center of ossification in scurvy, which may result from bleeding.
It must not be confused with Wimberger sign, pathognomonic of congenital syphilis.
The Wimberger sign, also called Wimberger corner sign, refers to localised bilateral metaphyseal destruction of the medial proximal tibias. It is a pathognomonic sign for congenital syphilis.
It must not be confused with Wimberger ring sign seen in scurvy, which is sometimes also referred to as...
The windsock sign refers to appearances seen in type A thoracic aortic dissections on contrast CT. It results from intimo-intimal intussusception between the true and false dissected lumens of the thoracic aorta. The altering density of contrast between the dissection lumens which taper distally...
The windsock sign can refer to different anatomical structures or pathologies:
windsock sign (duodenal web)
windsock sign (aortic dissection)
The windsock sign is a typical appearance of a duodenal web (intraluminal duodenal diverticulum) on upper gastrointestinal contrast series which consists of an intraduodenal barium-contrast filled sac that is surrounded by a narrow lucent line (web or intraluminal mucosal diaphragm) which is wel...
Wind-swept pelvis fracture is a combination a unilateral AP compression (open book) injury with a contralateral lateral compression injury.
It occurs when the internal rotation of one iliac wing causes a unilateral sacral compression fracture, while the same forces cause external rotation of t...