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.

802 results found
Article

Transposition of the great arteries

Transposition of the great arteries (TGA) is the most common cyanotic congenital cardiac anomaly with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalies 1  and can be assessed with echocardiography, gated cardiac CT, or cardiac MRI. Epidemiology...
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Transverse vaginal septum

Transverse vaginal (transvaginal) septum (TVS) is a type of rare congenital utero-vaginal anomaly (class II under the Rock and Adam classification). Epidemiology It is rare with a frequency of 1 in 70,000 females. Clinical presentation In the case of a complete septum, patients commonly pres...
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Triangular cord sign (biliary atresia)

The triangular cord sign is a triangular or tubular echogenic cord of fibrous tissue seen in the porta hepatis at ultrasonography and is relatively specific in the diagnosis of  biliary atresia1,2. This sign is useful in the evaluation of infants with cholestatic jaundice, helping for the diffe...
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Tricuspid atresia

Tricuspid atresia is a cyanotic congenital cardiac anomaly which is characterised by agenesis of the tricuspid valve and right ventricular inlet. There is almost always an obligatory intra-atrial connection through either an ASD or patent foramen ovale (PFO) in order for circulation to be comple...
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Trigonocephaly

Trigonocephaly refers to the triangular appearance of the frontal skull created by premature fusion of the metopic suture (metopic craniosynostosis) 2.  Trigonocephaly accounts for around 5% of all craniosynostosis cases. Pathology The metopic suture divides the frontal bones in the midline. ...
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Trilateral retinoblastoma

Trilateral retinoblastoma refers to the combination of retinoblastoma (usually bilateral) and pineoblastoma. This relationship highlights the close relationship between these highly aggressive small round blue cell tumours. It affects only a minority of patients with retinoblastoma (1.5-5%) and...
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Triphalangeal thumb

Triphalangeal thumb is considered a form of pre-axial polydactyly. Epidemiology Triphalangeal thumbs have an incidence of 1 in 25,000 7.  Pathology A triphalangeal thumb, as the name implies, has three phalanges instead of the usual two. There is an autosomal dominant genetic transmission 8....
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Triplane fracture

Triplane or triplanar fractures are of the distal tibia only occurring in adolescents. As the physiological closure of the physeal plate begins medially, the lateral (open) physis is prone to this type of fracture. The name is due to the fact of the fracture expanding both in frontal and lateral...
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Triple bubble sign

The triple bubble sign is the classic radiographic appearance observed in jejunal atresia 1,2. The appearance is due to a proximal obstruction caused by the atretric jejunum. It is equivalent to the double bubble sign, but a third bubble is seen because of proximal jejunal distention.
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Trisomies

Trisomies are chromosomal anomalies which usually occur due to non-disjunction. The vast majority of affected fetuses being spontaneously aborted, often very early during gestation. Only three are compatible with extra-uterine life (T13, T18, T21), and only one beyond early infancy (T21). In or...
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Truncus arteriosus

Truncus arteriosus is a cyanotic congenital heart anomaly in which a single trunk supplies both the pulmonary and systemic circulation, instead of a separate aorta and a pulmonary trunk. It is usually classified as a conotruncal anomaly. It accounts for up to 2% of congenital cardiac anomalies ...
Article

Tuberous sclerosis

Tuberous sclerosis (TS), also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterised by the development of multiple benign tumours of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has...
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Type II collagenopathy

Type II collagenopathies are a group of conditions collectively characterised by abnormalities in synthesis of collagen type II. This usually occurs due to a mutation in the COL2A1 gene. Entities that fall under this group include: achondrogenesis type II platyspondylic lethal skeletal dyspla...
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Ulegyria

Ulegyria refers to a shrunken and flattened cortex usually due to global hypoxic ischaemic injury in term infants, centering on the deepest portion of gyri, usually in the parasagittal region. It is here that perfusion is most tenuous and, therefore, most susceptible to ischaemic damage. Clinic...
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Ulnar dimelia

Ulnar dimelia or mirror hand syndrome is a rare congenital anomaly of the upper limb characterized by absence of the radial ray (including thumb), duplication of the ulna and duplication of the ulnar halves of the carpals, metacarpals and phalanges 1. Pathology Embryology The embryology of mi...
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Umbilical arterial catheters

Umbilical arterial catheters are used in neonatal care and need to be carefully assessed on all neonatal films.  Position The catheter should pass through the umbilicus, travel inferiorly through the umbilical artery, then in the anterior division of the internal iliac artery, into the common ...
Article

Umbilical-urachal sinus

An umbilical-urachal sinus belongs to the spectrum of congenital urachal anomalies and represents a non-communicating dilatation of the urachus at the umbilical end. Clinical presentation Presentation is commoner in children and rare in adult. Radiographic features An umbilical-urachal sinus...
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Umbilical venous catheters

Umbilical venous catheters are commonly used in the neonatal period for vascular access and should be carefully assessed for position on all neonatal films.  Position An umbilical venous catheter generally passes directly superiorly and remains relatively anterior in the abdomen. It passes thr...
Article

Unicameral bone cyst

Unicameral bone cysts (UBC), also known as simple bone cysts, are common benign non-neoplastic lucent bony lesions that are seen mainly in childhood and typically remain asymptomatic. They account for the S (simple bone cyst) in FEGNOMASHIC, the commonly used mnemonic for lytic bone lesions.  E...
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Unifocalisation procedure

A unifocalisation procedure is a corrective surgical technique used in patients with complete pulmonary artery atresia with major aortopulmonary collateral arteries (MAPCAs). In this technique, the collateral vessels supplying blood from the aorta directly to the lungs are brought into continuit...
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Urachal cyst

Urachal cysts are one of the manifestations of the spectrum of congenital urachal remnant abnormalities.  Clinical presentation Urachal cysts usually remain asymptomatic until complicated by infection or bleeding. Epidemiology Infected urachal cyst can occur at any age. Pathology Urachal c...
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Urbach-Wiethe disease

Urbach-Wiethe disease, also known as lipoid proteinosis or hyalinosis cutis et mucosae, is a rare autosomal recessive genodermatosis that primarily affects the skin, upper respiratory tract, and central nervous system (CNS). Epidemiology Urbach-Wiethe disease is a very rare condition, with few...
Article

Ureterocoele

Ureterocoeles represent congenital dilatation of the distal-most portion of the ureter. The dilated portion of the ureter may herniate into the bladder secondary to the abnormal structure of vesicoureteric junction (VUJ). Epidemiology Most ureterocoeles are congenital, usually associated with ...
Article

VACTERL association

VACTERL is an acronym that describes a non-random constellation of congenital anomalies. It is not a true syndrome as such and is equivalent to the VATER anomaly. Epidemiology The estimated incidence is 1 in 10,000-40,000 births 3. Pathology The acronym VACTERL derives from: V: vertebral an...
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Vascular rings and slings

Vascular rings and slings refer to the congenital vascular encirclement of the oesophagus and/or trachea by anomalous/aberrant vessels.  Epidemiology Vascular rings are rare, occurring in <1% of patients 1. No gender or ethnic predispositions have been identified 3.  Clinical presentation Ma...
Article

VATER

VATER (equivalent to VACTERL) is the non-random constellation of a number of congenital anomalies. V : vertebral anomalies A : anal atresia TE : tracheo-oesophageal fistulas R : radial ray hypoplasia, polydactyly and renal agenesis Epidemiology The prevalence of at least 3/5 anomalies oc...
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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, also known as the 5th ventricle, is an ependymal-lined, anatomical remnant, positioned at the transition from the tip of the conus medullaris to the origin of the filum terminale.  It represents the canalization and retrogressive differentiation of the caudal end of ...
Article

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 a problem encountered in young children.  For grading of vesicoureteric reflux, please refer to vesicoureteric reflux grading. Epidemiology The incidence of UTI is...
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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

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 photo-isomerisation within the rods and cones. Related pathology Patho...
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’s cycle). It therefore is vital for cellular ATP production, particularly in the central nervous system. Related pathology Pathological manifestations only occur with...
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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 is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D is a prohormone that exists in two forms in humans (D2 and D3). Cholecalciferol (D3) acts by regulating calcium and phosphorus intestinal absorp...
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Vitamin E

Vitamin E (the tocopherols) are a group of fat-soluble vitamins that act as an antioxidant. Hypovitaminosis E is rarely seen outside premature infants. Hypervitaminosis E is extremely rare as vitamin E is the least toxic of all the vitamins.
Article

Vitamin K

Vitamin K (phylloquinone (K1) and menaquinone (K2)) are a group of fat-soluble vitamins essential for normal blood-clotting function. Menaquinone is synthesised by normal flora in the intestine although the amount produced in vivo in the human gut is likely negligible. Vitamin K serves as a coen...
Article

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 Occurs from a mutation related to chromosome 11p13 3 which is in close proximity to 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 HRCT shows cysti...
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 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.
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 confused with Wimberger ring sign seen in scurvy, which is sometimes also referred to as...
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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