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.

963 results found
Article

Vein of Galen aneurysmal malformation

Vein of Galen aneurysmal malformations (VGAMs), probably better termed as median prosencephalic arteriovenous fistulas, are uncommon intracranial anomalies that tend to present dramatically during early childhood with features of a left-to-right shunt and high-output cardiac failure. Epidemiolo...
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Ventricular septal defect

Ventricular septal defects (VSD) represent defects in the interventricular septum that allow a haemodynamic communication between the right and left ventricles. It typically results in a left-to-right shunt. Epidemiology They represent one of the most common congenital cardiac anomalies and ma...
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Ventriculus terminalis

The ventriculus terminalis or terminal ventricle of Krause, also known as the 5th ventricle, is an ependymal-lined fusiform dilatation of the terminal central canal of the spinal cord, positioned at the transition from the tip of the conus medullaris to the origin of the filum terminale.  It re...
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Vesico-urachal diverticulum

Vesico-urachal diverticulum is one of the congenital urachal remnant abnormalities. Gross anatomy It is the proximal equivalent of a urachal umbilical sinus, representing a result of the failure of the urachus to close at the urinary bladder, forming an out-pouching of variable length from the...
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Vesicoureteric reflux

Vesicoureteric reflux (VUR) is the term for abnormal flow of urine from the bladder into the upper urinary tract and is typically encountered in young children.  For grading of vesicoureteric reflux, please refer to vesicoureteric reflux grading. Epidemiology The incidence of urinary tract in...
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Vesicoureteric reflux (grading)

Vesicoureteric reflux (VUR) grading divides vesicoureteric reflux according to the height of reflux up the ureters and degree of dilatation of the ureters: grade 1: reflux limited to the ureter grade 2: reflux up to the renal pelvis grade 3: mild dilatation of ureter and pelvicalyceal system ...
Article

Vesicovaginal reflux

Vesicovaginal reflux is a well-known entity rarely encountered by radiologists. It is a behavioural disorder, a type of dysfunctional elimination syndrome commonly encountered in pre-pubertal girls. It is defined as reflux of urine into the vaginal vault either in supine or upright position duri...
Article

Vitamin A

Vitamin A (the retinoids) are a group of fat-soluble vitamins required for many physiological functions, mainly vision, reproduction and epithelial maintenance. In the retina, a specific retinoid, 11-cis-retinal, is formed by photoisomerisation within the rods and cones. Related pathology Path...
Article

Vitamin B1

Vitamin B1 (thiamine) is a water-soluble vitamin that is an important coenzyme for two reactions in the citric acid cycle (Kreb cycle). It therefore is vital for cellular ATP production, particularly in the central nervous system. Related pathology Pathological manifestations only occur with t...
Article

Vitamin C

Vitamin C (ascorbic acid) is a water soluble vitamin that is a coenzyme for the formation of the structure protein collagen, particularly creating cross-linking of collagen fibres which greatly increases its tensile strength. It also acts as an antioxidant. Related pathology Pathological manif...
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Vitamin D

Vitamin D (calciferol) is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D exists in two main forms (vitamers) in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).  Vitamin D3 acts by re...
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Vitamin E

Vitamin E (the tocopherols) are a group of fat-soluble vitamins that act as antioxidants. hypovitaminosis E is rarely seen outside premature infants hypervitaminosis E is extremely rare as the toxicity of vitamin E is low except in chronic (usually >1 year) high doses. The commonest sequela is...
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Vitamin K

Vitamin K is a family of fat-soluble vitamins essential for normal blood-clotting function and comprises two vitamers that are found naturally: phytomenadione (also known as phylloquinone or K1) and menaquinone (or K2). Menadione is a synthetic molecule which is occasionally called vitamin K3 h...
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Voiding cystourethrography

Voiding cystourethrography (VCUG), also known as a micturating cystourethrography (MCU),  is a fluoroscopic study of the lower urinary tract in which contrast is introduced into the bladder via a catheter. The purpose of the examination is to assess the bladder, urethra, postoperative anatomy an...
Article

Waardenburg syndrome

Waardenburg syndrome is a rare congenital pigmentary disorder secondary to an abnormal distribution of neural crest-derived melanocytes during embryogenesis resulting in patchy areas of depigmentation. It is considered in the investigation of congenital sensorineural deafness. Epidemiology Est...
Article

WAGR syndrome

The WAGR syndrome stands for: Wilms tumours (greatly increased risk) aniridia genital anomalies mental retardation Pathology Genetics Occurs from a mutation related to chromosome 11p13 3 which is in close proximity to the WT1 gene. 
Article

Walker-Warburg syndrome

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...
Article

Waterston shunt

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, ...
Article

Weaver syndrome

Weaver syndrome (WS) is a rare congenital disorder. Clinical spectrum increased birth weight: fetal macrosomia early overgrowth macrocephaly accelerated osseous maturation: increased bone age typical facial features broad forehead hypertelorism long philtrum micrognathia large ears h...
Article

Weightbearing foot series (an approach)

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. Technique The weightbearin...
Article

Williams-Campbell syndrome

Williams-Campbell syndrome (WCS) is a rare form of congenital cystic bronchiectasis, in which distal bronchial cartilage is defective. Pathology It is thought to result from a deficiency of cartilage formation in the 4th to 6th order segmental bronchi. Radiographic features CT Shows cystic ...
Article

Wilms tumour

Wilms tumour, also known as nephroblastoma, is a malignant paediatric renal tumour. Epidemiology 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...
Article

Wilms tumour (staging)

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. stage I confined to kidney complete resection possible stage II loc...
Article

Wimberger ring sign

Wimberger ring sign , often simply just called Wimberger ring, refers to a circular calcification surrounding the osteoporotic epiphyseal centre of ossification in scurvy, which may result from bleeding. It must not be confused with Wimberger sign, pathognomonic for congenital syphilis. Histor...
Article

Wimberger sign

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...
Article

Wolffian duct

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. Development Female In the female, in...
Article

Wolf-Hirschhorn syndrome

Wolf-Hirschhorn syndrome (WHS) is an extremely rare chromosomal anomaly characterised by partial deletion of the p arm of chromosome 4 (4p16.3). Clinicopathological spectrum CNS agenesis of the corpus callosum hypertelorism coloboma craniofacial calvarial asymmetry cleft lip + / - palate...
Article

Wolman disease

Wolman disease is a rare autosomal recessive inborn error of metabolism resulting in the deposition of fats in multiple organs.  Clinical presentation Patients with Wolman disease typically present during the first two months of life with failure to thrive, diarrhoea and vomiting. Abdominal di...
Article

Wyburn-Mason syndrome

Wyburn-Mason syndrome (also known as Bonnet-Dechaume-Blanc syndrome) is a rare, nonhereditary neurocutaneous disorder that typically presents with unilateral vascular malformations that primarily involve the brain, orbits and facial structures. It is currently classified as a craniofacial arteri...
Article

Yasargil classification of vein of Galen aneurysmal malformations

The Yasargil classification is one of the two common systems for classifying vein of Galen malformations that is currently in use at the time of writing (mid 2016).  Classification type I: small pure cisternal fistula between the vein of Galen (voG) and either the pericallosal arteries (anteri...
Article

Yunis-Varón syndrome

Yunis Varón syndrome is a rare skeletal dysplasia. It is thought to be autosomal recessive. Radiographic features severe neurologic impairment cleidocranial dysplasia absent clavicles macrocrania diastasis of sutures micrognathia absent thumbs and distal phalanges of fingers hypoplasia ...
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

Zuelzer-Wilson syndrome

The Zuelzer-Wilson syndrome (total colonic aganglionosis) is a subset of Hirschsprung disease, in which the whole colon is aganglionic. It is uncommon and accounts for 2-13% of cases of Hirschsprung disease 3. Multiple procedures have been devised to treat the condition, including proctocolectom...

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