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.

1,101 results found
Article

≤11 ribs (differential)

≤11 ribs is associated with a number of congenital abnormalities and skeletal dysplasias, including: Down syndrome (trisomy 21) campomelic dysplasia kyphomelic dysplasias asphyxiating thoracic dysplasia (Jeune syndrome) short rib polydactyly syndromes trisomy 18 chromosome 1q21.1 deletion...
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18q-deletion syndrome

18q-deletion syndrome is a rare chromosomal anomaly where there is a deletion of part of the long arm of chromosome 18. Associated symptoms and findings vary widely, as do their severity. Characteristic clinical features include short stature, intellectual disability, hypotonia, facial and dista...
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22q11.2 deletion syndrome

22q11.2 deletion syndrome, also known as the DiGeorge syndrome or velocardiofacial syndrome, is a syndrome where a small portion of the chromosome 22 is lost and results in a variable but a recognisable pattern of physical and behavioral features. Epidemiology The estimated incidence is at ~ 1...
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Aase-Smith syndrome

Aase-Smith syndrome (or Aase syndrome) is an extremely rare congenital disorder. Clinical presentation congenital hypoplastic anemia - fetal anemia triphalangeal thumbs broad thumb abnormal clavicles cleft lip or cleft palate hypoplastic radii hydrocephalus (due to Dandy-Walker anomaly) ...
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Abdomen radiograph (pediatric)

The abdomen radiograph is a commonly requested examination in the pediatric patient. Children that present for abdominal x-rays are often very unwell, therefore specialized techniques and appropriate communication are essential for gaining the child's cooperation.  Indications Performing abdom...
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Abdominal migraine

Abdominal migraine (AM) is a syndrome which presents as recurrent episodes of severe abdominal pain, coupled with vasomotor symptoms, nausea and emesis. Historically it has tended to be a pediatric diagnosis, but is now increasingly seen in adults. It is one of the functional gastrointestinal di...
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Aberrant left pulmonary artery

Aberrant left pulmonary artery, also known as pulmonary sling, represents an anatomical variant characterized by the left pulmonary artery arising from the right pulmonary artery and passing above the right main bronchus and in between the trachea and esophagus to reach the left lung. It may lea...
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Absent septum pellucidum

An absent septum pellucidum may rarely be an isolated finding, or more commonly be seen in association with a variety of conditions. Epidemiology The septum pellucidum is partly or entirely absent in 2 or 3 individuals per 100,000 in the general population.  Pathology An absent septum pelluc...
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Absent thumb

An absent thumb can have many associations. They include: Fanconi anemia (pancytopenia-dysmelia syndrome) Franceschetti syndrome Holt-Oram syndrome phocomelia (e.g. thalidomide embryopathy) Poland syndrome (pectoral muscle aplasia and syndactyly) Rothmund-Thomson syndrome Seckel syndrome ...
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Abusive head trauma

Abusive head trauma is a term that is used to related to inflicted head injury that has occurred by either shaking, impact head trauma, or both. Pathology Intracranial injuries Subdural hemorrhage in a child should be viewed with suspicion. Most often, the subdural hemorrhages will demonstrat...
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Accessory ossicles

Accessory ossicles are secondary ossification centers that remain separate from the adjacent bone. They are usually round or ovoid in shape, occur in typical locations and have well defined smooth cortical margins on all sides. In most cases, they are congenital in origin, although they may occ...
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Accessory sutures

The parietal and occipital bones in particular are common regions for accessory sutures because of their multiple ossification centers. It is important to know these anatomic variations, mainly on the head trauma image studies in children, where it could be difficult to differentiate non-depres...
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Acetabular angle

The acetabular angle is a radiographic measurement used when evaluating potential developmental dysplasia of the hip (DDH).  It is most useful in patients who have started to ossify the epiphysis since ossification diminishes the usefulness of ultrasound. The angle is formed by a horizontal lin...
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Achondroplasia

Achondroplasia is a congenital genetic disorder resulting in rhizomelic dwarfism and is the most common skeletal dysplasia. It has numerous distinctive radiographic features.  Epidemiology It occurs due to sporadic mutations in the majority of cases but can be inherited as an autosomal dominan...
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Achondroplastic base of skull abnormalities

Achondroplasia is the most common cause of short-limb dwarfism. (For a general discussion, see the generic article on achondroplasia.) As the skull base forms by endochondral ossification whereas the skull vault by membranous ossification, there is a marked discrepancy in relative size as the s...
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Acrania anencephaly sequence

Acrania anencephaly sequence is the progression from a relatively normal-appearing exposed brain due to an absent cranium (acrania) to an amorphous brain mass (exencephaly) to no recognisable brain tissue (anencephaly) 1. Epidemiology The acrania anencephaly sequence begins with acrania, which...
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Acrocephalosyndactyly

Acrocephalosyndactyly syndromes (ACS) are a rare group of disorders collectively characterized by: calvarial anomalies, e.g. craniosynostoses digital anomalies, e.g. syndactyly Classification While there can be some overlap in features, they can be primarily classified into the following maj...
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Acromial apophysiolysis

Acromial apohysiolysis is a finding on shoulder MRI that may be encountered in patients with an unfused acromial apophysis. It is associated with athletes in throwing sports. Clinical presentation Presents with superior shoulder tenderness in a patient <25 years old, often in a young throwing ...
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Acute abdominal pain

Acute abdominal pain is a common acute presentation in clinical practice. It encompasses a very broad range of possible etiologies and diagnoses, and imaging is routinely employed as the primary investigative tool in its modern management. Terminology A subgroup of patients with acute abdomina...
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Acute idiopathic scrotal edema

Acute idiopathic scrotal edema (AISE) is a self-limiting condition characterized by marked edema of the skin and dartos fascia without involvement of the deeper layers, testes, or epididymis. It is an important condition to recognize in order to avoid unnecessary surgical exploration. Epidemiol...
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Acute mastoiditis

Acute mastoiditis refers to a suppurative infection of the mastoid air cells. It is the most common complication of acute otitis media. Terminology In acute otitis media, an inflammatory middle ear effusion is present that can freely move into the mastoid air cells. Consequently, some authors ...
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Acute necrotizing encephalitis of childhood

Acute necrotizing encephalitis of childhood (ANEC) is a rare type of encephalopathy characterized by multiple bilateral brain lesions, mainly involving the thalami, but also the putamina, internal and external capsules, cerebellar white matter, and the brainstem tegmentum. Epidemiology ANEC is...
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Acute pyelonephritis

Acute pyelonephritis is a bacterial infection of the renal pelvis and parenchyma most commonly seen in young women. It remains common and continues to have significant morbidity in certain groups of patients. Epidemiology The incidence of acute pyelonephritis parallels that of lower urinary tr...
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Acyanotic congenital heart disease

Acyanotic congenital heart disease comprises numerous etiologies, which can be divided into those with increased pulmonary vascularity (pulmonary plethora) and those with normal vascularity: increased pulmonary vascularity ventricular septal defect (VSD) atrial septal defect (ASD) atrioventr...
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Adams-Oliver syndrome

The Adams-Oliver syndrome (AOS) is a rare disorder characterized by aplasia cutis congenita (missing hair and/or skin) and variable degrees of terminal transverse limb defects. Associations polymicrogyria: can be associated with a variant of Adams-Oliver syndrome 3
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Adenoidal hypertrophy (children)

Adenoidal hypertrophy or enlargement in children is common and due to an increase in the size of the adenoids. For adenoidal enlargement in adults, which is much rarer and usually pathological, please see the separate article, adenoidal hypertrophy (adults). Clinical presentation nasal congest...
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Aflatoxins

Aflatoxins are naturally-occurring mycotoxins that are produced by Aspergillus species, especially Aspergillus flavus. They are acutely toxic and carcinogenic. Acute exposure High-level aflatoxin exposure can result in acute aflatoxicosis with acute hepatic necrosis, leading to cirrhosis, and ...
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Aicardi-Goutières syndrome

Aicardi-Goutières syndrome is a rare hereditary neurodegenerative disease which usually presents in early infancy with systemic and central nervous system inflammatory syndrome characterized by hepatosplenomegaly, vasculopathy and encephalopathy. Many of the features are similar to congenital TO...
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Aicardi syndrome

Aicardi syndrome is a rare severe developmental disorder. It results from an X-linked genetic defect that is fatal in males and therefore only manifests in females (except for rare 47, XXY cases). Note: Aicardi syndrome is distinct from Aicardi-Goutieres syndrome although both are named after J...
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AIDS embryopathy

Acquired immunodeficiency syndrome (AIDS) embryopathy is characterized by a group of dysmorphic features, which manifests either before or after birth in offsprings of women who are infected by HIV virus. The diagnosis, however, is in disfavour according to some authors 2. Pathology Transplace...
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Airway foreign bodies in children

Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common. Epidemiology Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.  Cl...
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Alagille syndrome

Alagille syndrome (AGS) is a congenital genetic multi-system disorder. Clinical presentation Infants typically present with symptoms relating to the liver where it is one of the most common causes of hereditary cholestasis. Genetics Alagille syndrome is inherited in an autosomal fashion with...
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Alexander disease

Alexander disease, also known as fibrinoid leukodystrophy, is a rare fatal leukodystrophy, which usually becomes clinically evident in the infantile period, although neonatal, juvenile and even adult variants are recognized. As with many other diseases with variable age of presentation, the earl...
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Alobar holoprosencephaly

Alobar holoprosencephaly is a subtype of holoprosencephaly and is the most severe of the classical three subtypes, with both semilobar and lobar holoprosencephaly having less severe clinical manifestations. For a general discussion of epidemiology, clinical presentation, and pathology, please r...
Article

Alpers syndrome

Alpers syndrome, also known as Alpers-Huttenlocher syndrome or progressive cerebral poliodystrophy, is a rare childhood neurodegenerative POLG-related disorder. Along with Leigh syndrome, it is one of the commonest childhood mitochondrial disorders 1.  Epidemiology Alpers syndrome is incredibl...
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Alpha angle (developmental dysplasia of the hip)

The alpha angle is a measurement used in the ultrasonographic assessment of developmental dysplasia of the hip (DDH). The angle is formed by the acetabular roof to the vertical cortex of the ilium and thus reflects the depth of the bony acetabular roof. This is a similar measurement to the acet...
Article

Alpha fetoprotein

Alpha fetoprotein (AFP) is an important plasma protein synthesized by the yolk sac and fetal liver. In adults its main utility is as a tumor marker, primarily for hepatocellular carcinoma or teratoma. Functionally it is the fetal homologue of albumin, i.e. it acts as a major carrier protein in t...
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Alternating radiolucent and radiodense metaphyseal lines

Alternating radiolucent and radiodense metaphyseal lines can be seen with a number of conditions and the differential diagnosis is wide: growth arrest lines bisphosphonate therapy rickets: especially those on prolonged treatment, e.g. vitamin D dependent rickets osteopetrosis chemotherapy ...
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Anal atresia

Anal atresia, or imperforate anus, refers to a spectrum of anorectal abnormalities ranging from a membranous separation to complete absence of the anus. Epidemiology The estimated incidence is 1 in 5000 live births. Pathology Clinically there is no anal opening. Subtypes can be classified in...
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Anatomy curriculum

The anatomy curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core anatomy knowledge for radiologists and imaging specialists. General anatomy Neuroanatomy Head and neck anatomy Thoracic anatomy Abdominal and pelvic anatomy Spinal anat...
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Aneurysmal bone cyst

Aneurysmal bone cysts (ABC) are benign expansile tumor-like bone lesions of uncertain etiology, composed of numerous blood-filled channels, and mostly diagnosed in children and adolescents. Epidemiology Aneurysmal bone cysts are primarily seen in children and adolescents, with 80% occurring in...
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Anomalous left coronary artery from the pulmonary artery

Anomalous left coronary artery from the pulmonary artery (ALCAPA), also known as Bland-White-Garland syndrome (BWG), is a rare congenital coronary artery anomaly and is considered one of the most severe of such anomalies. There are two forms, based on onset of disease, each of which has differe...
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Anoxic brain injury

Anoxic brain injury, also known as global hypoxic-ischemic injury, is seen in all age groups (from antenatal to the elderly) as a result of numerous etiologies. The pattern of injury depends on a number of factors including: age of the patient (brain maturity) neonatal hypoxic-ischemic encepha...
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Anterior fontanelle

The anterior or frontal fontanelle (or fontanel) is the diamond-shaped soft membranous gap at the junction of the coronal and sagittal sutures. It persists until approximately 18-24 months after birth, after which it is known as the bregma. The precise timing of the anterior fontanelle closure i...
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Anterior humeral line

The anterior humeral line is key to demonstrating normal elbow alignment and should be used whenever reading a pediatric elbow radiograph to exclude a subtle supracondylar fracture. The rule A line drawn down the anterior surface of the humerus should intersect the middle third of the capitell...
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Anterior inferior iliac spine avulsion injury

Anterior inferior iliac spine (AIIS) avulsion injuries are one of the six main types of pelvic apophyseal avulsion fractures. Subacute or chronic avulsion injuries can be mistaken for a pseudotumor.  Epidemiology As with many pelvic avulsion injuries, they most often occur in adolescents (most...
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Anterior lenticonus

Anterior lenticonus is present when the anterior surface of the ocular lens assumes a conical shape. Epidemiology It can be unilateral or bilateral. Bilateral anterior lenticonus is associated with Alport syndrome. Clinical presentation Decreased visual activity and irregular refraction that...
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Anterior vertebral body beaking

Anterior vertebral body beaking occurs in a number of conditions and may emanate from the central portion or the lower third of the vertebral body. Middle third Morquio syndrome 1 (middle for Morquio) Lower third Hurler syndrome 2 achondroplasia 3 pseudoachondroplasia 4 cretinism 5 Down ...
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Antley-Bixler syndrome

Antley-Bixler syndrome (ABS), also known as trapezoidocephaly-synostosis syndrome, is a rare autosomal dominant or recessive condition characterized by craniosynostosis and extra-cranial synostoses. Mid-facial hypoplasia is also common. Epidemiology It is a very rare condition with only 50 cas...
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Antral nipple sign

The antral nipple sign refers to redundant pyloric mucosa protruding into the gastric antrum and is seen in pyloric stenosis. See also cervix sign of pyloric stenosis target sign of pyloric stenosis shoulder sign of pyloric stenosis
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Aorto-ventricular tunnel

Aorto-ventricular tunnel (AVT) is an extremely rare form of congenital heart disease, representing an anomalous extracardiac communication between the ascending aorta and the left or right ventricles. Terminology In most cases the anomalous communication is between the aorta and the left ventr...
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Apert syndrome

Apert syndrome (also known as type I acrocephalosyndactyly) is a syndrome that is predominantly characterized by skull and limb malformations. Epidemiology The estimated incidence is 1 case per 65-80,000 pregnancies. Risk factors increased paternal age has been proposed 6 Associations CNS ...
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Apgar score

Apgar score was originally described by Virginia Apgar (American anaesthesiologist, 1909-1974) in 1952. Helpfully, her surname is also a useful mnemonic for remembering the 5 factors: each is graded as 0, 1 or 2 with a total possible score of 10. The lower the score the worse the prognosis. Th...
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Apophyseal avulsion fractures of the pelvis and hip

Apophyseal avulsion fractures of the pelvis and hip are relatively common among physically active adolescents and young adults. Epidemiology Pelvic and hip apophyseal injuries typically occur in the 14 to 25 year age range. Mechanism Kicking sports, such as soccer, and gymnastics are frequen...
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Apophysis of the proximal 5th metatarsal

The apophysis of the proximal 5th metatarsal lies laterally and is oriented longitudinally parallel to the shaft. Apophysis of the fifth metatarsal base appears on plain radiographs at age 12 for boys and 10 for girls. Fusion of the apophysis to the metatarsal base usually occurs within the fol...
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Appendicitis

Appendicitis is inflammation of the vermiform appendix. It is a very common condition in general radiology practice and is one of the main reasons for abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis. Epidemiology Acute appendicitis is typically a d...
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Apple-peel intestinal atresia

Apple-peel intestinal atresia, also known as type IIIb or Christmas tree intestinal atresia, is a rare form of small bowel atresia in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply in a spiral resembling an apple peel. Oft...
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Arterial switch procedure

The arterial switch procedure, also known as the Jatene switch procedure, is an intervention designed to correct D-transposition of the great arteries (D-TGA) at the level of the aorta and main pulmonary artery. It is generally preferred over atrial switch procedures for simple D-TGA due to impr...
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Ascariasis

Ascariasis is due to infection with the Ascaris lumbricoides adult worm and typically presents with gastrointestinal or pulmonary symptoms, depending on the stage of development.   Epidemiology Ascaris lumbricoides is widely distributed in tropical and subtropical regions and in other humid ar...
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Askin tumor

The original description of the Askin tumor (by Askin and Rosai in 1979 1), and many studies following it have led to a great deal of confusion. Until recently it has been considered a separate entity or as a type of peripheral primitive neuroectodermal tumor, usually of the chest wall. However...
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Asplenia

Asplenia refers to absence of the spleen thereby leading to deficient splenic function. Epidemiology Seen in 3% of neonates with structural heart disease and in 30% of patients who die from cardiac malposition. The male-to-female ratio is 2:1. Pathology Asplenia can be classified into two  t...
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Asplenia syndrome

Asplenia syndrome, also known as right isomerism or Ivemark syndrome, is a type of heterotaxy syndrome. Epidemiology There is an increased male predilection. Asplenia syndrome is usually diagnosed in neonates 4. Clinical presentation In contrast to polysplenia syndrome, most patients die bef...
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Atelosteogenesis

Atelosteogenesis (AO) refers to a group of lethal skeletal dysplasias. Pathology Sub types atelosteogenesis type I atelosteogenesis type II atelosteogenesis type III 4
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Athlete heart syndrome

Athlete heart syndrome refers to adaptations in both cardiac structure and function seen in people engaged in high-performance and endurance physical exercise. Epidemiology The prevalence of the condition has increased due to the increased popularity of recreational exercise, approx 3.6/100,00...
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Atresia

Atresia refers to a situation where there is underdevelopment of a structure with very rudimentary remnant tissues. This contrasts with agenesis, in which there is no development of the structure at all. The term atresia is often used with hollow structures such as a bronchus or intestine.  For...
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Atrial septal defect

Atrial septal defect (ASD) is the second most common congenital heart defect after ventricular septal defects and the most common to become symptomatic in adulthood. They are characterized by an abnormal opening in the atrial septum allowing communication between the right and left atria. Due t...
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Atrioventricular septal defect

Atrioventricular septal defects (AVSDs), also known as atrioventricular canal defects or endocardial cushion defects, comprise of a relatively wide range of defects involving the atrial septum, ventricular septum and one or both of the tricuspid or mitral valve. They can represent 2-7% of congen...
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Atypical callosal dysgenesis

Atypical callosal dysgenesis is a term used to denote an unusual pattern of dysgenesis of the corpus callosum. The development of the corpus callosum occurs between the 12th and 16-20th weeks of gestation 2-3. It begins with the genu and then continues posteriorly along the body to the splenium...
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Atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumors (AT/RT) are an uncommon WHO Grade IV tumor, which in the vast majority of cases occurs in young children less than two years of age. It most frequently presents as a posterior fossa mass. AT/RT often resembles medulloblastoma by imaging and even H&E microscopy, ...
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Autosomal recessive osteopetrosis

Infantile autosomal recessive osteopetrosis is a subtype of osteopetrosis, a bone disease of dysfunctional osteoclasts that results in the overgrowth of bone. It is a more severe form that tends to present earlier. Hence, it is referred to as "infantile" and "malignant" compared to its autosomal...
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Autosomal recessive polycystic kidney disease

Autosomal recessive polycystic kidney disease (ARPKD) is one of many pediatric cystic renal diseases. On imaging, it usually presents on ultrasound with enlarged echogenic kidneys with multiple small cysts. Liver involvement with coarse echotexture, biliary tract cystic changes, and portal hype...
Article

Bacterial tracheitis

Exudative tracheitis, also known as bacterial tracheitis, membranous croup or membranous laryngotracheobronchitis, is a rare, but potentially life-threatening cause of upper airway obstruction. Epidemiology Typical age ranges from 6 to 10 years of age. Clinical presentation Clinically it pre...
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Bado classification of Monteggia fracture-dislocations

The Bado classification is one of the more widely used classifications for Monteggia fracture-dislocations and mainly focuses on the radial component. Four types are recognized and are generally based on the principle that the direction in which the apex of the ulnar fracture points is the same ...
Article

Banana sign (cerebellum)

The banana sign is one of the many notable fruit inspired signs. This sign is seen on axial imaging through the posterior fossa of fetuses with associated conditions such as  Chiari II malformation and/or spina bifida. In Chiari II malformation, the banana sign describes the way the cerebellum...
Article

Band heterotopia

Band heterotopia, also known as double cortex syndrome, is a form of diffuse grey matter heterotopia affecting almost only women. Refractory epilepsy is present in nearly all affected patients, with partial complex and atypical absence epilepsy being the most common syndromes. On imaging, this ...
Article

Barium sulfate

Barium sulfate (BaSO4), often just called barium in radiology parlance, is a salt of barium (Ba), a metallic chemical element with atomic number 56. Barium is considered one of the heavy metals. Unlike barium and many of its other salts, barium sulfate is insoluble in water and therefore very li...
Article

Barlow disease (disambiguation)

Barlow disease could refer to: infantile scurvy - named after Sir Thomas Barlow (1845-1945) who demonstrated infantile scurvy to be the same disease as adult scurvy Barlow disease - mitral valve: form of mitral valve prolapse - named after John Brereton Barlow (1924-2008) 2
Article

Barth syndrome

Barth syndrome (BTHS), also known as 3-methylglutaconic aciduria type II, is an extremely rare X-linked multisystem disorder that is usually diagnosed in infancy. Epidemiology Barth syndrome has an estimated prevalence of 1 in 300,000-400,000 live births. Clinical presentation It is characte...
Article

Bartter syndrome

Bartter syndrome is a rare inherited renal disorder. Pathology Bartter syndrome is characterized by hyperplasia of the juxtaglomerular cells along with: hypokalemia metabolic alkalosis hypotension/normotension elevated plasma renin  elevate aldosterone antenatal polyhydramnios Classifi...
Article

Baumann angle

Baumann angle, also known as the humeral-capitellar angle, is used for the evaluation of the displacement of  pediatric supracondylar humeral fractures. It is measured on a frontal radiograph, with elbow in extension. This angle is formed  by the humeral axis and a straight line through the epi...
Article

Becker muscular dystrophy

Becker muscular dystrophy (BMD) is a dystrophinopathy that is considered to be a milder form of Duchenne muscular dystrophy. Epidemiology It may be present in 3 to 6 per 100,000 male births. The condition is extremely rare in females due to its inheritance pattern, as discussed below. Clinica...
Article

Beckwith-Wiedemann syndrome

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder characterized by a unique set of features that can consist of: macroglossia: most common clinical finding 4 otic dysplasia ref omphalocoele localized gigantism / macrosomia hemihypertrophy cardiac anomalies pancreatic i...
Article

Benign enlargement of the subarachnoid space in infancy

Benign enlargement of the subarachnoid spaces in infancy (BESS or BESSI) also known as benign external hydrocephalus (BEH) is, as per the name, a benign enlargement of the subarachnoid spaces in infants. It usually involves the frontal lobe subarachnoid spaces, and it is characterized clinically...
Article

Benign liver tumors (pediatric)

Pediatric benign liver tumors are a relatively rare, but important group of conditions. Importantly, the commonest cause of a benign liver tumor is specific to the pediatric population. The list in descending order of frequency is: infantile hepatic hemangioma (previously hemangioendothelioma) ...
Article

Bent bone dysplasias (differential)

Bent bone dysplasias are a class of dysplasia included in a 2010 classification of genetic skeletal disorders 1. campomelic dysplasia Stuve-Weidemann dysplasia kyphomelic dysplasias, a diverse class, including congenital bowing of the long bones cartilage-hair hypoplasia (CHH; metaphyseal d...
Article

Bernese periacetabular osteotomy

Bernese periacetabular osteotomy, also known as Ganz osteotomy, is an orthopedic procedure involving osteotomy surrounding the acetabulum and subsequent angulation to improve coverage of the femoral head by the acetabulum. It is performed in the context of hip dysplasia. There is an osteotomy th...
Article

Beta angle (developmental dysplasia of the hip)

The beta angle is a measurement used in the ultrasonographic assessment of developmental dysplasia of the hip (DDH). It is defined as the angle formed between the vertical cortex of the ilium and the triangular labral fibrocartilage (echogenic triangle) and thus reflects the femoral head cartil...
Article

Bilateral frontoparietal polymicrogyria

Bilateral frontoparietal polymicrogyria (BFPP) is a rare genetic condition consisting of extensive bilateral perisylvian polymicrogyria.  As is the case with many areas of medicine transitioning from phenotypical to molecular/genetic definitions, it has been postulated what bilateral frontopari...
Article

Bilateral thalamic glioma

Bilateral thalamic gliomas are rare but characteristic low-grade astrocytomas that occur in both children and young adults. Clinical presentation Presentation may vary with age. Young children with bilateral thalamic glioma often have signs of increased intracranial pressure and movement disor...
Article

Biliary atresia

Biliary atresia (BA) is a congenital biliary disorder, which is characterized by an absence or severe deficiency of the extrahepatic biliary tree. It is one of the most common causes of neonatal cholestasis, often causing cirrhosis immediately and leading to death and accounts for over half of c...
Article

Biotin deficiency

Biotin deficiency is very rare. Biotin is a vitamin which acts as an enzymatic cofactor with a key role in energy production and the synthesis of fats. Biotin is present in a diverse range of cereals, nuts, seeds and eggs. Hence, true deficiency is unusual. It has been observed in the following ...
Article

Biotinidase deficiency

Biotinidase deficiency is a rare autosomal recessive condition in which the body is unable to break down the conjugated form of biotin (vitamin B7), resulting in low levels of bioavailable biotin, and clinical biotin deficiency. Epidemiology Profound deficiency (<10% of normal level) is estima...
Article

Birth defects linked to antithyroid drug treatment in pregnancy

Birth defects linked to antithyroid drug treatment in pregnancy have for a long time been known to exist. A recent Danish register-based cohort study has assessed the degree of association of antithyroid drugs (ATD), such as methimazole (MMI) / carbimazole (CMZ) and propylthiouracil (PTU), and t...

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