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.

1,168 results found
Article

Sunset eye sign

The sunset eye sign (also known as the setting sun phenomenon) is a clinical phenomenon encountered in infants and young children with raised intracranial pressure (seen in up to 40% of children with obstructive hydrocephalus and 13% of children with shunt dysfunction 1).  It consists of an up-...
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Supracondylar humeral fracture

Supracondylar humeral fractures, often simply referred to as supracondylar fractures, are a classic pediatric injury which require vigilance as imaging findings can be subtle. Epidemiology Simple supracondylar fractures are typically seen in younger children, and are uncommon in adults; 90% ar...
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Surgically-created cardiac shunts (mnemonic)

A mnemonic for surgically-created cardiac shunts for congenital heart disease is: Great Flow Really Would Be Perfect​ The mnemonic is ordered by the position of the shunt antegrade to normal blood flow through the heart, proceeding from the systemic venous system into the right heart, and then...
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Suspected physical abuse

Suspected physical abuse (previously termed non-accidental injury, NAI) in infants and young children represent both ethical and legal challenges to treating physicians. Radiologists may be the first clinical staff to suspect non-accidental injuries when confronted with a particular injury patt...
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Syndactyly

Syndactyly (plural: syndactylies) refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly/simple syndactyly) or may involve bone (bony syndactyly/complex syndactyly). Epidemiology The overall estimated incidence is at ~1 per 2,500 to 5,000...
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Synovial hemangioma

Synovial hemangiomas are rare benign vascular malformations that occur in relation to the joint. It is sometimes considered a subtype of soft tissue hemangiomas. Epidemiology The lesions typically present in children and young adults. Occasionally patients can have recurrent haemarthroses 8. ...
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Syphilis

Syphilis is the result of infection with the gram negative spirochete Treponema pallidum, subspecies pallidum. It results in a heterogeneous spectrum of disease with many systems that can potentially be involved, which are discussed separately.  Epidemiology Despite the discovery of penicillin...
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Tadpole sign

The tadpole sign, also known as the lollipop sign, refers to a characteristic morphology of post-traumatic bridging vein thrombosis with a rounded "head" and a tapering "tail". The finding demonstrates a high specificity for abusive head trauma, a sub-type of non-accidental injury, and should wa...
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Takeuchi procedure

The Takeuchi procedure refers to a direct anastomosis of the anomalous left coronary artery from the pulmonary artery directly to the aorta was described in the 1970s and currently remains the procedure of choice. An intrapulmonary aortocoronary tunnel or baffle was performed by Takeuchi prior ...
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Tamm-Horsfall proteins

Tamm-Horsfall proteins, also known as uromodulin, may be a cause of echogenic renal pyramids in a neonate. Tamm-Horsfall proteins are physiologically excreted by the renal tubular epithelium. They are most often encountered on neonatal renal ultrasound, where the concentrated proteins in the re...
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Target sign (intussusception)

The target sign of intestinal intussusception, also known as the doughnut sign or bull's eye sign. The appearance is generated by concentric alternating echogenic and hypoechogenic bands. The echogenic bands are formed by mucosa and muscularis whereas the submucosa is responsible fo the hypoec...
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Target sign (pyloric stenosis)

The target sign of pyloric stenosis is a sign seen due to hypertrophied hypoechoic muscle surrounding echogenic mucosa, seen in pyloric stenosis. This is likened to that of a target. See also antral nipple sign cervix sign of pyloric stenosis shoulder sign of pyloric stenosis
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Taussig-Bing anomaly

Taussig-Bing anomaly is a rare congenital heart malformation and is one of the variants of double outlet right ventricle. It consists of transposition of the aorta to the right ventricle and malposition of the pulmonary artery with subpulmonary ventricular septal defect. History and etymology ...
Article

Tc-99m DMSA

Tc-99m DMSA (2,3 dimercaptosuccinic acid) is a technetium radiopharmaceutical used in renal imaging to evaluate renal structure and morphology, particularly in pediatric imaging for detection of scarring and pyelonephritis. DMSA is an ideal agent for assessment of the renal cortex as it binds to...
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Tc-99m pertechnetate

Tc-99m pertechnetate (Na+ 99mTc O4-) is one of the technetium radiopharmaceuticals used in imaging of thyroid, colon, bladder and stomach. Technetium (99mTc) has eight oxidation states 6, from -1 to +7; specifically, the oxidation state of technetium in the pertechnetate anion (99mTcO4-) is +7....
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Technetium agents

Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with 99mTc constitutes a coordination complex in which ligands bond to a central atom of 99mTc by coordinate covalent bonds 4 . The radioactive techne...
Article

Tectal beaking (midbrain)

Tectal beaking refers to the fusion of the midbrain colliculi into a single beak pointing posteriorly and invaginating into the cerebellum. It is seen with a Chiari type II malformation. Terminology The term bird beak sign is used in a number of other contexts: see bird beak sign (disambiguati...
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Tectal glioma

Tectal gliomas fall under the grouping of childhood brainstem gliomas and unlike the other tumors in that group they are typically low grade astrocytomas with good prognosis.  Epidemiology Tectal plate gliomas are encountered in children and adolescents 4. A male predilection has sometimes bee...
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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.
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Telltale triangle sign

The telltale triangle sign, also known as the triangle sign or telltale triangle, is a radiographic sign seen on plain abdominal radiographs in a supine, cross table lateral or decubitus view that signifies presence of pneumoperitoneum, of any cause 1,2. It describes the appearance of a radiolu...
Article

Temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common type of partial epilepsy, with often characteristic imaging and clinical findings. It is divided into two broad groups: medial epilepsy most common involves the mesial temporal lobe structures most frequently due to mesial temporal sclerosis l...
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Tension gastrothorax

Tension gastrothorax describes a rare life-threatening condition caused by mediastinal shift due to a distended stomach herniating into the thorax through a diaphragmatic defect.  Clinical presentation Presentation is generally with acute and severe respiratory failure, with clinical features ...
Article

Terminal myelocystocele

Terminal myelocystoceles are an uncommon form of spinal dysraphism representing marked dilatation of the central canal of the spinal cord, herniating posteriorly through a dorsal spinal defect. The result is a skin-covered mass in the lower lumbar region, consisting of an ependyma-lined sac.  E...
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Terminal zones of myelination

The terminal zones of myelination are located at the posterior aspect of the lateral ventricles (the peritrigonal regions) and are the only part of the cerebral white matter that may exhibit high T2 signal in a normal brain at 2 years of age, when myelination of cerebral white matter normally be...
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Tethered cord syndrome

Tethered cord syndrome is a neurological disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal canal. Clinical presentation Tethered cord syndrome is a clinical diagnosis based on neurologic deterioration involving the lower spinal cord 7. Patients ...
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Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart condition with many cases presenting after the newborn period. It has been classically characterized by the combination of ventricular septal defect (VSD), right ventricular outflow tract obstruction (RVOTO), overriding aorta...
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Thalassemia

Thalassemia is an autosomal recessive hemoglobinopathy that originated in the Mediterranean region. The genetic defect causes a reduction in the rate of globin chain synthesis which causes the formation of abnormal hemoglobin molecules. The resultant microcytic anemia is the characteristic prese...
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Thalidomide embryopathy

Thalidomide embryopathy refers to a syndrome resulting from in utero exposure to thalidomide, and is characterized by multiple fetal anomalies. Fetal exposure to thalidomide occurred primarily from 1957 to 1961, when it was used as a treatment for nausea in pregnant women.  Epidemiology  Expos...
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Thanatophoric dysplasia

Thanatophoric dysplasia is a lethal skeletal dysplasia. It is the most common lethal skeletal dysplasia followed by osteogenesis imperfecta type II.  Epidemiology The estimated incidence is around 1:25,000-50,000 3. Pathology Genetics It results from a mutation coding for the fibroblast gro...
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Thiemann disease

Thiemann disease (also called familial osteoarthropathy of the fingers or osteonecrosis of the base of phalanx) is a non-inflammatory disorder of unknown etiology and refers to osteonecrosis of the epiphyses of the phalanges which leads to deformity of the fingers. Epidemiology Thiemann diseas...
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Thoracopagus conjoined twins

Thoracopagus conjoined twins are, as the name suggests, conjoined twins united at their thorax. Fusion is typically face-to-face, at the upper thorax to the umbilicus with a common sternum, diaphragm, and upper abdominal wall. Very often a common pericardial sac is present as well as a degree o...
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Thrombocytopenia with absent radius syndrome

Thrombocytopenia with absent radius (TAR) syndrome is primarily characterized by the following two features: fetal thrombocytopenia absent fetal radii (bilaterally) with the presence of both thumbs Epidemiology The condition is extremely rare with an estimated incidence of 0.4 per 100,000 bi...
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Thumb sign (epiglottitis)

The thumb sign in epiglottitis is a manifestation of an edematous and enlarged epiglottis which is seen on lateral soft-tissue radiograph of the neck, and it suggests a diagnosis of acute infectious epiglottitis. This is the radiographic corollary of the omega sign 1-3. See also Thumb sign is ...
Article

Thurstan Holland fragment

The Thurstan Holland fragment (or 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 indicates a type 2 Salter-Harris fracture 1. History and etymology It is named after Cha...
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Thymic hyperplasia

Thymic hyperplasia is a disorder whereby there is hyperplasia of the thymus gland.  Pathology Thymus hyperplasia can be subdivided into two forms:  true thymic hyperplasia lymphoid thymic hyperplasia Both true thymic hyperplasia and lymphoid hyperplasia manifest as diffuse symmetric enlarge...
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Thymic notch sign

The thymic notch sign represents the normal thymus in a newborn on a frontal chest radiograph. Interruption of the cardiac silhouette forms a notch, which may be seen on either side, but more frequently is seen on the left side.   See also thymic sail sign thymic wave sign  
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Thymic sail sign

The thymic sail sign represents a triangular-shaped inferior margin of the normal thymus seen on a neonatal frontal chest radiograph. It is more commonly seen on the right side, but can also be bilateral. It is seen in 3-15% of all cases. This sign should not be confused with the spinnaker sail ...
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Thymic wave sign

Thymic wave sign refers to the indentation of the normal thymus in young children by the ribs, resulting in a wavy border on chest radiograph.  There are at least 3 described signs relating to a normal thymus in infants; thymic sail sign, thymic notch sign and thymic wave sign. Being able to id...
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Thyroglossal duct cyst

Thyroglossal duct cysts (TGDC) are the most common type of congenital neck cysts and pediatric neck masses. They are typically located in the midline and are the most common midline neck mass in young patients. They can be diagnosed with multiple imaging modalities including ultrasound, CT and M...
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Thyroid transcription factor 1 deficiency

Thyroid transcription factor 1 deficiency is a situation characterized by mutations in the gene encoding thyroid transcription factor, NKX2-1. Pathology It can result in neurological, thyroid, and pulmonary dysfunction (including neonatal respiratory distress). Children can have a range of mil...
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Tibia vara

Tibia vara (also known as genu varus and bow-leggedness) is a varus deformity with outward bowing at the knee and medial angulation (inward) of the lower leg in relation to the thigh's coronal axis. The differential of bow-legging in children is long, with common causes including Blount disease...
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Tibiotalar slant

Tibiotalar slant is the superolateral inclination of the tibial plafond, and results in an ankle valgus deformity. There are a number of causes 1: trauma, i.e. distal tibial fractures osteomyelitis and/or septic arthritis juvenile idiopathic arthritis haemophilic arthropathy sickle cell dis...
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Tight filum terminale syndrome

Tight filum terminale syndrome, or tight filum syndrome, is a subtype of the tethered cord syndrome that is attributed to a thick, short, and/or otherwise inelastic filum terminale rather than other tethering agents. Terminology The term "tight filum terminale syndrome" is synonymous with "tet...
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Tit sign (pyloric stenosis)

The tit sign of pyloric stenosis is seen on barium studies as an outpouching of the lesser curve of the stomach proximal to the impression of the hypertrophied pyloric muscle. It represents the transient trap of contrast medium between a peristaltic wave and the thickened, hypertrophied pyloric...
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Toddler fracture

A toddler fracture is a minimally or undisplaced spiral fracture, usually of the tibia, typically encountered in toddlers. It is a potentially difficult diagnosis to establish on account of both the symptoms and imaging findings being subtle. Terminology The term has sometimes also been used t...
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Torsion of the appendix testis

Torsion of the appendix testis (occasionally called torsion of the hydatid of Morgagni) is the most common cause of an acute painful hemiscrotum in a child. The appendix testis is located at the upper pole of the testis (between the testis and the head of the epididymis). The normal appendix te...
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Torticollis

Torticollis (wryneck) is a clinical finding of head tilt with or without rotational spinal malalignment. It is not a diagnosis in itself and there are a wide range of underlying conditions. It is most common in the pediatric age group.  Pathology Torticollis can be acute (<1 week) or chronic (...
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Torus fracture

Torus fractures, also known as buckle fractures, are incomplete fractures of the shaft of a long bone that is characterized by bulging of the cortex. They result from trabecular compression due to an axial loading force along the long axis of the bone. They are usually seen in children, frequent...
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Total anomalous pulmonary venous return

Total anomalous pulmonary venous return (TAPVR) is a cyanotic congenital heart anomaly with an abnormal drainage anatomy of the entire pulmonary venous system. This contrasts with partial anomalous pulmonary venous return (PAPVR) where only part of the pulmonary venous anatomy is abnormal. In T...
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Total repair of tetralogy of Fallot

Total repair of tetralogy of Fallot is a corrective surgical procedure that involves closure of the ventricular septal defect (VSD) and relief of right ventricular outflow tract (RVOT) obstruction. Procedure Most patients with tetralogy of Fallot (TOF) undergo elective surgical repair between ...
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Townes-Brocks syndrome

Townes-Brocks syndrome (Renal-Ear-Anal-Radial (REAR) syndrome) is a rare autosomal dominant disease characterized by renal, anal, ear, and thumb abnormalities. Clinical presentation The major manifestations of this syndrome include: renal: displaced or rotated kidneys, horseshoe kidney, p...
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Tracheal buckling

Tracheal buckling is a normal finding in young infants when it is more flexible. There is typically deviation of the trachea anteriorly and to the right (up to 90°) and any other configuration (i.e. to the left or posteriorly) should raise the possibility of underlying pathology.  Practical poi...
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Tracheal stenosis

Tracheal stenosis is usually acquired following intubation or tracheostomy. It can also arise as part of the spectrum of tracheobronchial stenosis. Inflammation and pressure necrosis of the tracheal mucosa most commonly occur at either the tracheostomy stoma or at the level of the tube balloon....
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Trampoline fracture

Trampoline fractures are transverse fractures of the proximal tibial metaphysis that occur in children while jumping on a trampoline (or inflatable castle). The fracture is thought to occur when a second, usually heavier individual causes the jumping surface to recoil upwards as the unsuspectin...
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Transient intussusception

Transient (non-obstructing) intussusception without a lead point is known to occur in both adults and children and occurs more frequently than was previously reported. Most commonly, transient intussusception in adults is idiopathic, incidental, and of no clinical consequence 4. Uncommonly, tra...
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Transient synovitis of the hip

Transient synovitis of the hip refers to a self-limiting acute inflammatory condition affecting the synovial lining of the hip. It is considered one of the most common causes of hip pain and limping in young children. Over 90% of hip joint effusions in children tend to be due to transient synovi...
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Transient tachypnea of the newborn

Transient tachypnea of the newborn, also known as retained fetal fluid or wet lung disease, presents in the neonate as tachypnea for the first few hours of life, lasting up to one day. The tachypnea usually resolves within 48 hours.  Epidemiology Transient tachypnea is one of the commonest cau...
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Transposition of the great arteries

Transposition of the great arteries (TGA) (also known as transposition of the great vessels (TGV)) is the most common cyanotic congenital cardiac anomaly presenting during the newborn period, with cyanosis in the first 24 hours of life. It accounts for up to 7% of all congenital cardiac anomalie...
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Transverse vaginal septum

Transverse vaginal (transvaginal) septum (TVS) is a type of rare congenital uterovaginal 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 prese...
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Treacher Collins syndrome

Treacher Collins syndrome, also known as mandibulofacial dysostosis, is an autosomal dominant genetic abnormality and results from bilateral malformations of 1st and 2nd branchial arches.  Epidemiology The incidence is estimated at approximately 1 in 50,000 live births, with 60% of cases being...
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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 for the diagnosis of biliary atresia 1,2. This sign is useful in the evaluation of infants with cholestatic jaundice, helping in the diffe...
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Tricuspid atresia

Tricuspid atresia is a cyanotic congenital cardiac anomaly which is characterized 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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Trident acetabulum

Trident acetabulum is an appearance which can be seen in several skeletal dysplasias 1. It is characterized 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 appearance has...
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Trident appearance (disambiguation)

The trident appearance (or sign) can refer to a variety of entities: trident acetabulum trident hand trident sign (osmotic demyelination) trident sign (persistent trigeminal artery) History and etymology The trident is a three-pronged lance employed for spearing fish, and in Classical myth...
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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. It may be used for the clinical appearance of the hand or the appearance on imaging, particularly reminiscent of a trident on fetal ultrasound 5. It can be seen ...
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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. I...
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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 tumors. 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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Triradiate cartilage

The triradiate cartilage is the Y- shaped epiphyseal plate that occurs at the junction where the ischium, ilium, and pubis meet in the skeletally immature skeleton.   The vertical component of the "Y" is the meeting of the ischium and pubic bone. The anterior arm is the junction of the ilium an...
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Trisomies

The trisomies are chromosomal anomalies which usually occur due to non-disjunction. The vast majority of affected fetuses are spontaneously aborted, often very early during gestation. Only three are compatible with extrauterine life (T13, T18, T21), and only one beyond early infancy (T21). In o...
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True hermaphroditism

True hermaphroditism is a form of disorder of gender development.  Pathology Patients with true hermaphroditism have mosaicism of 46XX and 46XY. They therefore have both ovarian and testicular tissues. Subtypes There are three forms of true hermaphroditism: unilateral true hermaphroditism ...
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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 ...
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Tuberous sclerosis

Tuberous sclerosis, also known as tuberous sclerosis complex or Bourneville disease, is a neurocutaneous disorder (phakomatosis) characterized by the development of multiple benign tumors of the embryonic ectoderm (e.g. skin, eyes, and nervous system). Epidemiology Tuberous sclerosis has an in...
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Tubulinopathy

Tubulinopathy refers to a wide spectrum of cortical malformations that result from defects in genes encoding the tubulin protein that regulates neuronal migration during brain development. Clinical presentation Some series report a high prevalence of seizures during infancy which may the initi...
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Type I choledochal cyst

Type I choledochal cysts appear as a fusiform or cystic dilatation of the extrahepatic biliary system (common bile duct +/- common hepatic duct). Epidemiology Although uncommon in Western countries (1:100,000 to 1:150,000), they are the most common type of biliary cyst. Their prevalence may be...
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Type II collagenopathy

Type II collagenopathies are a group of conditions collectively characterized 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...
Article

Typhoid fever

Typhoid fever or just typhoid is an infectious disease caused by the Salmonella enterica serovar Typhi bacterium, usually spread by the orofecal route. The condition is characterized by severe fever, acute systemic symptoms, with occasionally serious enterocolic complications. Terminology Do n...
Article

Ulegyria

Ulegyria refers to a shrunken and flattened cortex usually due to global hypoxic ischemic 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 ischemic damage. Clinical...
Article

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...
Article

Ulnar hemimelia

Ulnar hemimelia is a rare congenital upper limb anomaly characterized by complete or partial absence of the ulna bone. Epidemiology Incidence is estimated at 1/100,000-150,000 live births, with a male to female ratio of 3:2. Associations Ulnar hemimelia may be associated with other skeletal ...
Article

Umbilical arterial catheters

Umbilical arterial catheters (UACs) are used in neonatal care for arterial sampling 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 i...
Article

Umbilical artery

The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation and an active vessel giving supply to the bladder. In the adult, the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery. Su...
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Umbilical cord

The umbilical cord is a fetal organ that connects the placenta to the developing fetus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.  The umbilical cord inserts into the center of the placental bulk and into the fetus at the umbilicus. Variations in inse...
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...
Article

Umbilical vein

The umbilical vein is the conduit for blood returning from the placenta to the fetus until it involutes soon after birth. The umbilical vein arises from multiple tributaries within the placenta and enters the umbilical cord, along with the (usually) paired umbilical arteries. Once it enters the...
Article

Umbilical venous catheters

Umbilical venous catheters (UVCs) are commonly used in neonates 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 through...
Article

Umbilicus

The umbilicus is the fibrous remnant of the foetal attachment of the umbilical cord after birth. All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the sternum and the p...
Article

Undifferentiated embryonal sarcoma of the liver

Undifferentiated embryonal sarcomas of the liver are rare, aggressive, and malignant liver tumors encountered in the pediatric population.  Epidemiology Approximately 90% of cases occur in patients under 15 years of age, most commonly between 6 and 10 years of age, but some cases have been rep...
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...
Article

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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Upper limb radiography (pediatric)

Upper limb radiography involves plain film imaging of the shoulder, humerus, ulna, radius, metacarpals and carpal bones in pediatric patients. Depending on the patients' age, the difficulty of the examination will vary, often requiring a specialist trained radiographer familiar with a variety of...

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