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, mental retardation, hypotonia, facial and distal ske...
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.
The estimated incidence is at ~ 1...
Aase-Smith syndrome (or Aase syndrome) is an extremely rare congenital disorder.
congenital hypoplastic anemia - fetal anemia
cleft lip or cleft palate
hydrocephalus (due to Dandy-Walker anomaly)
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...
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...
An absent septum pellucidum may rarely be an isolated finding, or more commonly be seen in association with a variety of conditions.
The septum pellucidum is partly or entirely absent in 2 or 3 individuals per 100,000 in the general population.
An absent septum pelluc...
An absent thumb can have many associations. They include:
Fanconi anemia (pancytopenia-dysmelia syndrome)
phocomelia (e.g. thalidomide embryopathy)
Poland syndrome (pectoral muscle aplasia and syndactyly)
Seckel syndrome ...
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...
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...
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...
Achondroplasia is a congenital genetic disorder resulting in rhizomelic dwarfism and is the most common skeletal dysplasia. It has numerous distinctive radiographic features.
It occurs due to sporadic mutations in the majority of cases but can be inherited as an autosomal dominan...
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...
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.
The acrania anencephaly sequence begins with acrania, which...
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.
Presents with superior shoulder tenderness in a patient <25 years old, often in a young throwing ...
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.
Acute mastoiditis refers to a suppurative infection of the mastoid air cells. It is the most common complication of acute otitis media.
In acute otitis media, an inflammatory middle ear effusion is present that can freely move into the mastoid air cells. Consequently, some authors ...
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.
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.
The incidence of acute pyelonephritis parallels that of lower urinary tr...
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)
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.
polymicrogyria: can be associated with a variant of Adams-Oliver syndrome 3
Adenoidal hypertrophy or enlargement is common in childhood and is due to an increase in the size of the adenoids.
nasal congestion: adenoid facies
chronic or recurrent otitis media due to their proximity to the Eustachian tubes
Aflatoxins are naturally-occurring mycotoxins that are produced by Aspergillus species, especially Aspergillus flavus. They are acutely toxic and carcinogenic.
High-level aflatoxin exposure can result in acute aflatoxicosis with acute hepatic necrosis, leading to cirrhosis, and ...
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...
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 Je...
Acquired immuno deficiency 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.
Airway foreign bodies in children are potentially fatal, which is why immediate recognition is important. Unfortunately, delayed diagnosis is common.
Children under the age of four years are at increased risk of foreign body (FB) aspiration, with a slight male predominance 1.
Alagille syndrome (AGS) is a congenital genetic multi-system disorder.
Infants typically present with symptoms relating to the liver where it is one of the most common causes of hereditary cholestasis.
AGS is inherited in an autosomal fashion with a mutation of...
Alexander disease (AD), 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...
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...
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.
Alpers syndrome is incredibl...
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...
Alpha fetoprotein (AFP) is an important plasma protein synthesised 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...
Alternating radiolucent and radiodense metaphyseal lines can be seen with a number of conditions and the differential diagnosis is wide:
growth arrest lines
rickets: especially those on prolonged treatment, e.g. vitamin D dependent rickets
Anal atresia, or imperforate anus, refers to a spectrum of anorectal abnormalities ranging from a membranous separation to complete absence of the anus.
The estimated incidence is 1 in 5000 live births.
Clinically there is no anal opening. Subtypes can be classified in...
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.
Head and neck anatomy
Abdominal and pelvic anatomy
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.
Aneurysmal bone cysts are primarily seen in children and adolescents, with 80% occurring in...
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...
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...
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 fontanelle normally measures between 0.6-3.6 cm (me...
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.
A line drawn down the anterior surface of the humerus should intersect the middle third of the capitell...
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 pseudotumour.
As with many pelvic avulsion injuries, they most often occur in adolescents (mos...
Anterior vertebral body beaking occurs in a number of conditions and may eminate from the central portion or the lower third of the vertebral body.
Morquio syndrome 1 (middle for Morquio)
Hurler syndrome 2
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.
It is a very rare condition with only 50 cas...
The antral nipple sign refers to redundant pyloric mucosa protruding into the gastric antrum and is seen in pyloric stenosis.
cervix sign of pyloric stenosis
target sign of pyloric stenosis
shoulder sign of pyloric stenosis
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.
In most cases the anomalous communication is between the aorta and the left ventr...
Apert syndrome (also known as type I acrocephalosyndactyly) is a syndrome that is predominantly characterized by skull and limb malformations.
The estimated incidence is 1 case per 65-80,000 pregnancies.
increased paternal age has been proposed 6
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.
Apophyseal avulsion fractures of the pelvis and hip are relatively common among physically active adolescents and young adults.
Pelvic and hip apophyseal injuries typically occur in the 14 to 25 year age range.
Kicking sports, such as soccer, and gymnastics are frequen...
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...
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.
Acute appendicitis is typically a d...
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...
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...
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.
Ascaris lumbricoides is widely distributed in tropical and subtropical regions and in other humid ar...
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.
Asplenia refers to absence of the spleen thereby leading to deficient splenic function.
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.
Asplenia can be classified into two t...
Asplenia syndrome (also known as right isomerism or Ivemark syndrome) is a type of heterotaxy syndrome.
There is an increased male predilection. Asplenia syndrome is usually diagnosed in neonates.4
In contrast to polysplenia syndrome, most patients die bef...
Atelosteogenesis (AO) refers to a group of lethal skeletal dysplasias.
atelosteogenesis type I
atelosteogenesis type II
atelosteogenesis type III 4
Athlete heart syndrome refers to adaptations in both cardiac structure and function seen in people engaged in high-performance and endurance physical exercise.
The prevalence of the condition has increased due to the increased popularity of recreational exercise, approx 3.6/100,00...
Atrial septal defects (ASDs) are 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. Du...
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...
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...
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, ...
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...
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...
Exudative tracheitis, also known as bacterial tracheitis, membranous croup or membranous laryngotracheobronchitis, is a rare, but potentially life-threatening cause of upper airway obstruction.
Typical age ranges from 6 to 10 years of age.
Clinically it pre...
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 ...
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...
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 ...
Barth syndrome (BTHS), also referred to as 3-methylglutaconic aciduria type II is an extremely rare X-linked multi-system disorder that is usually diagnosed in infancy.
It is characterized by:
fetal cardiomyopathy: (dilated fetal cardiomyopathy (DCM) +/- endocardial fibroelastosis (EFE) +/- le...
Bartter syndrome is a rare inherited renal disorder.
Bartter syndrome is characterized by hyperplasia of the juxtaglomerular cells along with:
hypotension or normotension
elevated plasma renin
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...
Beals syndrome is a rare connective tissue disorder that has some resemblance to the Marfan syndrome. Affected individuals have arachnodactily, contractures and ear anomalies but without any ocular or cardiac anomalies.
Becker muscular dystrophy (BMD) is a dystrophinopathy that is considered to be a milder form of Duchenne muscular dystrophy.
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.
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
localized gigantism / macrosomia
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...
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)
Bent bone dysplasias are a class of dysplasia included in a 2010 classification of genetic skeletal disorders 1.
kyphomelic dysplasias, a diverse class, including
congenital bowing of the long bones
cartilage-hair hypoplasia (CHH; metaphyseal d...
Bernese osteotomy, also known also 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 through the sup...
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...
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...
Bilateral thalamic gliomas are rare but characteristic low-grade astrocytomas that occur in both children and young adults.
Presentation may vary with age. Young children with bilateral thalamic glioma often have signs of increased intracranial pressure and movement disor...
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...
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...
Birth fractures of the clavicle occur in 0.5-1% of vaginal deliveries and are the most frequent birth-related fracture. They are most commonly seen following normal, uncomplicated births but there is recognized increased incidence with high birth weight babies, forceps delivery and shoulder dyst...
Birth trauma relates to those conditions caused by both physical/mechanical and hypoxic injuries.
Birth trauma occurs in ~5 per 1000 births 2.
Blalock-Taussig shunt, also known as Blalock-Thomas-Taussig shunt, is a palliative procedure designed to increase pulmonary arterial blood flow in patients with right ventricular outflow tract obstruction (e.g. tetralogy of Fallot) or during initial staged repair of hypoplastic left heart syndro...
Blepharophimosis is dysplasia of the eyelids, where there is horizontal shortening of palpebral fissure. It is often associated with ptosis.
Blepharophimosis is a feature of Dubowitz syndrome and Smith Lemli Opitz syndrome.
Blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES) is c...
Block vertebra is a type of vertebral anomaly where there is a failure of separation of two or more adjacent vertebral bodies. It is an anatomic variant.
In a block vertebra, there is partial or complete fusion of adjacent vertebral bodies.
Blount disease refers to a local disturbance of growth of the medial aspect of the proximal tibial metaphysis and/or epiphysis that results in tibia vara. The condition is commonly bilateral.
There is no recognized inheritance pattern.
Clinically, the chi...
Blueberry muffin syndrome refers to patients with multiple cutaneous metastatic lesions from primary adrenal neuroblastoma.
A Bochdalek hernia is a form of congenital diaphragmatic hernia. They occur posteriorly and are due to a defect in the posterior attachment of the diaphragm when there is a failure of pleuroperitoneal membrane closure in utero. Retroperitoneal structures may prolapse through the defect, e.g. ret...
A helpful mnemonic for remembering the features of a Bochdalek hernia is:
B: back and medial, usually on the left side
B: bad (associated with pulmonary hypoplasia)
Bone age assessment is used to radiologically assess the biological and structural maturity of immature patients from the hand and wrist x-ray appearances. It forms an important part of the diagnostic and management pathway in children with growth and endocrine disorders. It is helpful in the di...