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 is drained by separate ureters, e...
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.
A Weil osteotomy is a from of osteotomy performed in the foot. It is considered a common technique used in the treatment of lesser metatarsal deformities of the forefoot. It is designed to make a controlled shortening of the length of the metatarsal in the transverse plane.
The Weiss classification is one of the classification systems used for lateral humeral condyle fractures and is based on the degree of displacement measured on an internal oblique view of the elbow:
type 1: <2 mm displacement
type 2: 2-4 mm displacement
type 3: >4 mm displacement
The degree ...
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
Wellens syndrome (also referred to as LAD coronary T-wave syndrome) refers to a specific ECG abnormality in the precordial T-wave segment. It can be associated with a critical stenosis of the proximal left anterior descending artery.
Wells criteria for deep venous thrombosis is a risk stratification score and clinical decision rule to estimate the pretest probability for acute deep venous thrombosis (DVT). It is intended to be combined with noninvasive diagnostic tests (e.g. ultrasound or D-dimer) for suspected cases. D-dime...
The Wells criteria for pulmonary embolism is a risk stratification score and clinical decision rule to estimate the probability for acute pulmonary embolism (PE) in patients in which history and examination suggests acute PE is a diagnostic possibility. It provides a pre-test probability which, ...
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 characterized by
scleroderma-like skin changes such ...
Wernicke aphasia, also known as receptive aphasia or fluent aphasia, is the inability to grasp the meaning of spoken or written words and sentences while producing connected speech is not greatly affected.
Receptive aphasia is usually caused by injury to the dominant posterior temporal lobe (We...
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 mammillary bodies, dorsomedial thalami, ...
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...
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.
The theory behind the sign is either obstruction of the pulmonary artery or distal vasoconstriction in hypoxic lung 3.
In one stu...
The WFNS (World Federation of Neurosurgical Societies) grading system uses the Glasgow Coma Scale and presence of focal neurological deficits to grade the severity of subarachnoid hemorrhage. This grading system was proposed in 1988, and this is one of the accepted systems (although not consider...
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 sulphate) while containing smaller amounts of fibroblasts and macropha...
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The wheel within a wheel sign describes one of several possible ultrasound findings of hepatic candidiasis. The finding consists of a round lesion with three layers corresponding to the following histopathological changes 2:
peripheral hypoechoic area (fibrosis)
middle hyperechoic area (inflam...
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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 ...
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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. The gastrointestinal manifestations of Tropheryma whipplei are also known as intestinal lipodystrophy.
Extensive infiltration of the lamina propria with large macrophages infected by intracellular T. whipplei ca...
Neurological manifestations of Whipple disease are rare. Whipple disease may appear as a primary neurological disorder in rare cases. It is rarely found as a cause of progressive neurological deterioration in patients.
It has been suggested that neurological involvement will eventually occur in...
Thoraco-pulmonary manifestations of Whipple disease are uncommon and present in the late stages of the disease.
Lung involvement is seen in 35-60% of patients with gastrointestinal whipple disease.
Majority of patients present with non-specific pulmonary an...
The Whipple procedure (or partial pancreaticoduodenectomy) is considered the definitive surgical operation to resect carcinoma of the head of the pancreas, periampullary carcinoma, or duodenal carcinoma 1.
In the procedure, the head of the pancreas and adjacent duodenum is resected. ...
Whipple triad is the clinical presentation of pancreatic insulinoma and consists of:
fasting hypoglycemia (<50 mg/dL)
symptoms of hypoglycemia
immediate relief of symptoms after the administration of IV glucose
History and etymology
The triad and also the Whipple procedure were both named a...
The whirlpool sign, also known as the whirl sign, is seen when a structure twists upon itself resembling the rotating masses of water of a whirlpool. Described whirlpool signs include:
whirlpool sign (mesentery): bowel rotates around its mesentery leading to whirls of the mesenteric vessels
The whirlpool sign of the mesentery, also known as the whirl sign, is seen when the bowel rotates around its mesentery leading to whirls of the mesenteric vessels.
The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation).
The whirlpool sign or whirl sign of ovarian torsion is characterized by the appearances of a twisted ovarian pedicle seen on US or even on CT.
The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation).
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 is the substance of the brain and spinal cord that contains the fiber tracts of neuronal axons in the central nervous system. The term is due to the paler color of the lipid-rich myelin that encase the axons in the tracts compared to the grey matter, which contains predominantly...
The white matter buckling sign is helpful in distinguishing an extra-axial intracranial 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 edema (which would usually expand gyri, if the mass were i...
White matter changes in HIV have overlapping appearances and varied in etiology. 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 in the brain, also known as white matter fibers, 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)
The spinal cord has numerous tracts of white matter that ascend and descend in the peripheral substance of the cord. They can be divided by their location and function:
anterior corticospinal tract
medial longitudinal fasiculus
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. Additionally, the unila...
The World Health Organization classifies anal canal neoplasms into intraepithelial neoplasms and invasive neoplasms which are further divided to epithelial and non-epithelial tumors and secondary lesions:
squamous cell carcinoma of anal canal
adenocarcinoma of anal canal
The WHO classification of anal margin tumors or perianal skin tumors 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 tumors is the most widely accepted system for classifying CNS tumors and was based on the histological characteristics of the tumor. Although the most recent version of the 'blue book' is the 4th edition from 2007, an update has been released in 2016 3, which should...
The WHO classification scheme for thymic epithelial tumors is one of many classifications systems for thymoma and related tumors, and classifies them according to histology:
spindle cell thymoma
type ab: mixed thymoma
type b1: lymphocyte rich
The WHO criteria have been developed in the 1980s to standardized reporting of cancers in clinical trial. These criteria Nowadays, newer criteria often based on the WHO criteria (such as RECIST, mRECIST, Choi criteria, Lugano response criteria), have widely replaced the WHO criteria in clinical...
WHO (World Health Organization) grading of CNS tumors 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 tumors.
It should be noted that at the time...
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 astrocytomas...
Benign renal tumors were histologically classified according to the WHO in 2004 as follows 1:
Renal cell tumors
renal papillary adenoma - renal adenoma
metanephric adenoma of kidney
metanephric adenofibroma of kidney
metanephric stromal tumor of kidney
The WHO histological classification is a detailed classification of tumors of the uterine cervix.
squamous tumors and precursors
squamous cell carcinoma, not otherwise specified - 8070/3
keratinizing - 8071/3
non-keratinizing - 8072/3
basaloid - 8083/3
verrucous - 8051/3...
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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:
haemophilic arthropathy (most commonly bilateral)
juvenile rheumatoid arthritis (most commonly bilateral)
tuberculosis arthropathy (usually unilateral) 3
Widening of diploic space refers to expansion of the spongy or cancellous bone between the inner and outer tables of the calavarium. The diploic space is the medullary cavity of the skull, and a location of normal physiologic hematopoiesis in adults. Thus, expansion of this structure most common...
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 disk level on lateral radiographs and the normal value of the presacral space is <15 mm in adults....
Widow's peak hair anomaly refers to a frontal hairline projection.
Prominent V-shaped hairline projection. Ocular hypertelorism might be...
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 syndrome: an ocular motility disturbance due to fibrosis of the extraocu...
Wilhelm C Roentgen (1845-1923) was a German physicist who is celebrated globally for his discovery of x-rays on November 8th 1895.
Wilhelm Conrad Roentgen (Röntgen in German) was born on March 27th 1845 in Lennep, Germany. He attended the primary and secondary school run by Martinus...
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.
Shows cystic ...
Williams syndrome (WS) is characterized 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
The Will Rogers phenomenon is encountered in many disciplines but is particularly relevant to radiology in the setting of staging scans and is due to reclassifying borderline individuals also known as stage migration 1.
The most common example in medicine is upstaging certain patients with mali...
Wilms tumor, also known as nephroblastoma, is a malignant pediatric renal tumor.
Wilms tumors 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 pea...
Wilms' tumor staging is largely anatomical and relates to the invasion and spread of the tumor. Where there is invasion or metastasises, prognosis is poorer. Wilms tumor, 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 due to abnormal accumulation of copper. It is characterized by early onset liver cirrhosis with CNS findings most frequently affecting the basal ganglia and midbrain.
This article aims to discuss the central n...
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 secondary to the accumulation of copper in the articular cartilage.
Reported manifestations include 1-3
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 , often simply just called Wimberger ring, 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 for 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 mixed up with Wimberger ring sign seen in scurvy, which is sometimes also confusingly re...
Windowing, also known as grey-level mapping, contrast stretching, histogram modification or contrast enhancement is the process in which the CT image greyscale component of an image is manipulated via the CT numbers; doing this will change the appearance of the picture to highlight particular st...
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...
The (absent) pedicle sign, also called the winking owl sign, occurs on plain film when a pedicle is absent.
The term, winking owl sign, where the missing pedicle corresponds to the closed eye, the contralateral pedicle to the other open eye, and the spinous process to the beak of the animal on ...
The Winquist classification of femoral shaft fractures is based on fracture comminution and was proposed by Winquist in 1980. This classification is used with regards to management decision making, in determining whether a fracture requires an intramedullary nail or open reduction.
Type 0: no ...
Wirsungocele refers to a cystic dilatation of the pancreatic duct of Wirsung, which is the portion of ventral duct between the dorsal-ventral junction and major duodenal papilla. It is believed to be analogous to choledochocele and santorinicele.
It may be an incidental f...
Wiskott-Aldrich syndrome (WAS) is a rare immunodeficiency disease with a characteristic phenotype that includes:
petechiae, bloody diarrhea, epistaxis due to thrombocytopenia with small platelets
eczema starts in first month of life
recurrent infections with encapsulated b...
The Woggle technique is the purse-string suture modified using to close a puncture site after a percutaneous procedure.
Techniques common to all procedure include:
a purse-string suture is done around the introducer sheath (the short plastic tube placed within a vein or artery)
cut the needle...
Wolff-Chaikoff effect is an autoregulatory phenomenon, whereby a large amount of ingested iodine acutely inhibits thyroid hormone synthesis within the follicular cells, irrespective of the serum level of thyroid-stimulating hormone (TSH) 1.
The Wolff-Chaikoff effect is thought to be...
The Wolffian duct (also known as the mesonephric duct) is one of the paired embryogenic tubules that drain the primitive kidney (mesonephros) to the cloaca. In both the male and the female the Wolffian duct develops into the trigone of the urinary bladder.
In the female, in...
Wolf-Hirschhorn syndrome (WHS) is an extremely rare chromosomal anomaly characterized by partial deletion of the p arm of chromosome 4 (4p16.3).
agenesis of the corpus callosum
cleft lip + / - palate...
Wolman disease is a rare autosomal recessive inborn error of metabolism resulting in the deposition of fats in multiple organs.
Patients with Wolman disease typically present during the first two months of life with failure to thrive, diarrhea and vomiting. Abdominal dis...
There are a number of words we never use at Radiopaedia.org. This may be the result of an international consensus on correct spelling, other times it is a local decision about how we can improve consistency on the site.
This is separate to the differences between British (UK) and American (US) ...
World Radiography Day is an annual event held on November 8th to celebrate the anniversary of the discovery of x-rays organised by the International Society of Radiographers and Radiological Technologists (ISRRT).
World Radiography Day occurs simultaneously with the International Day of Radiolo...
Wormian bones (a.k.a. intrasutural bones) is the name given to the additional small bones sometimes found between the cranial sutures of the bones of the skull vault, most commonly in relation to the lambdoid suture. Some reserve the term Wormian bones to just the intrasutural bones proximate to...
A mnemonic to remember ten of the numerous conditions associated with Wormian bones is:
P - pyknodysostosis
O - osteogenesis imperfecta
R - rickets
K - kinky hair syndrome
C - cleidocranial dysostosis
H - hypothyroidism/hypophosphatasia
O - otopalatodigital syndrome
Wound dehiscence is a surgical complication whereby there is rupture of a wound along the surgical scar (dehiscence, refers to "splitting open"). This may occur on the skin surface, or along a deeper suture line.
Presentation may be with pain (e.g. sternal dehiscence), or...
Wrisberg rips are longitudinal vertical meniscal tears. They occur at the at the junction of the ligament of Wrisberg and the posterior horn of the lateral meniscus, and are commonly associated with anterior cruciate ligament tears 1.
The carpal bridge view an additional view to the three view series of the wrist and carpal bones. It is used to assess the dorsal aspect of the scaphoid, lunate and the triquetrum.
the patient is seated alongside the table
dorsal aspect of affected wrist is placed on the dete...
The carpal tunnel view is an axial projection to demonstrate the medial and lateral prominences and the concavity. It can be utilized to investigate potential hook of hamate, pisiform and trapezium factures.
patient stands with the back facing the table
palmar surface of hand...