This is a basic article for medical students and other non-radiologists
Paediatric radiology curriculum for medical students covers the fundamental imaging modalities, conditions and presentations on children that require imaging.
As expected and of more importance compared to adults, when con...
Paediatric renal tumours and masses are another group of diseases (just like cystic renal diseases in both the adult and child) that are bewildering in their number, nomenclature and overlapping findings.
Wilms tumour: common in older children 1-8 years old
There is a wide range of primary malignancies that results in paediatric skeletal metastases 1:
leukaemia: although not truly metastases
clear cell sarcoma: Wilms’ variant
Ewing’s sarcoma: lung metastases much more common
Paediatric urinary tract infections are common and are a source of significant imaging in young children.
Paediatric urinary tract infections affect up to 2.8% of all children every year, with approximately 2% of boys and 8% or more of girls developing a urinary tract infection at...
The British National Institute for Health and Care Excellence (NICE) published the “Urinary tract infection in under 16s: diagnosis and management” in 2007 as a guideline for paediatric urinary tract infection (UTI) management, including imaging, prophylaxis and follow-up 1.
This article inten...
Pallister-Hall syndrome is characterised by:
renal anomalies, e.g horseshoe kidney
The pancake adrenal gland or "lying down" adrenal sign refers to the flattened disc-like appearance of the adrenal gland in the renal fossa when the ipsilateral kidney is absent. When a pancake adrenal gland is present careful examination should be performed to exclude renal agenesis or renal ec...
Pancreatoblastomas are rare paediatric tumours of the pancreas. However, they are the most common pancreatic neoplasm of childhood and are often associated with a raised alpha-fetoprotein.
There is slight male predilection. Usually occurs in the first decade of life with a mean ag...
Panner disease is an osteochondrosis of the capitellum. It should be distinguished from osteochondritis dissecans of the elbow which also affects the capitellum.
Panner disease is typically seen in children (5-10 years of age), although it is also seen in throwers due to repeated...
A parachute mitral valve is a valvular congenital abnormality usually identified in infants or young children though is can present later in adulthood.
Parachute mitral valves occur when all the chordae tendineae are attached to a single papillary muscle origin. Unlike the normal sit...
Parapagus twins are conjoined twins that lie side-by-side with ventrolateral fusion.
This type of conjoined twins usually shares the umbilicus, abdomen, and pelvis. The conjoined pelvis may have a single symphysis pubis and one or two sacra.
The lower gastrointestinal tract (single colon and...
Parotid infantile haemangiomas are the most common parotid tumour of childhood. They usually run a characteristically benign course.
The median age at diagnosis is 4 months 1. There is female preponderance with a male:female ratio of 1:3.
Presents as en enl...
Patau syndrome (also known as trisomy 13) is considered the 3rd commonest autosomal trisomy.
This along with Down syndrome (T21) and Edward syndrome (T18) are the only three trisomies to be compatible with extrauterine life. However, few infants live more than a few days.
Patellar sleeve fractures represent chondral or osteochondral avulsion injury at the inferior pole of the patella.
Patellar sleeve fractures occur in the paediatric population, typically between 8 and 12 years of age.
Unlike Sinding-Larsen-Johannson disease...
Patent ductus arteriosus or arteriosum (PDA) is a congenital cardiac anomaly where there is persistent patency of the ductus arteriosus, a normal connection of the fetal circulation between the aorta and the pulmonary arterial system that develops from the 6th aortic arch.
A patent urachus is one of the spectrum of congenital urachal anomalies. It has occasionally been termed "urachal fistula".
A patent urachus is often diagnosed in neonates when urine is noted leaking from the umbilicus. The umbilicus may also have an abnormal appearance o...
Neonatal hypoxic ischaemic brain injuries can manifest in different patterns of involvement depending on the severity and timing of the insult. When considering the perinatal maturation process of the brain and the severity of an insult, it is possible to understand the various manifestations.
The PECARN (Paediatric Emergency Care Applied Research Network) traumatic brain injury algorithm is a clinical decision rule that aims to identify children at very low risk of clinically important traumatic brain injury (ci-TBI) 1. This validated paediatric algorithm predicts likelihood of the a...
Pectus carinatum, otherwise known as a pigeon chest, refers to a chest wall deformity in which the sternum protrudes anteriorly. It is less common than pectus excavatum.
scoliosis (common) 2
cyanotic congenital heart disease (uncommon)
Pectus excavatum, also known as funnel chest, is a congenital chest wall deformity characterised by concave depression of the sternum, resulting in cosmetic and radiographic alterations.
It is the most common chest wall deformity, accounting for approximately 90% of cases, occurs ...
Pelvic osteotomy relates to an orthopaedic treatment for developmental acetabular dysplasia of the hip.
The main purpose of pelvic osteotomy is the prevention of early degenerative changes by stabilisation of the hip and redistribution of joint loading. It is obtained by surgical reshaping/remo...
PELVIS or LUMBAR syndrome is the combination of pelvic haemangiomas with other extracutaneous abnormalities. The syndrome may be incomplete.
external genital malformations
Pelviureteric junction (PUJ) obstruction/stenosis, also known as ureteropelvic junction (UPJ) obstruction/stenosis, can be one of the causes of an obstructive uropathy. It can be congenital or acquired with a congenital PUJ obstruction being one of the commonest causes of antenatal hydronephrosi...
The pentalogy of Cantrell is an extremely rare phenomenon with an incidence estimated at around 6 per million live births 3.
It encompasses the following 5 main features 1.
ectopia cordis (abnormal location of heart)
pericardial defect or sternal cleft
The pentalogy of Fallot is a variant of the more common tetralogy of Fallot, comprising the classical four features with the addition of an atrial septal defect or patent ductus arteriosus The five features therefore are:
ventricular septal defect (VSD)
right ventricular outlfow tract narro...
Pepper syndrome is of interest only (the term is not readily used in day-to-day practice), and refers to primary adrenal neuroblastoma with extensive liver metastases 1. In essence, it refers to stage 4S neuroblastoma (see staging of neuroblastoma).
Pericallosal lipomas are fat-containing lesions occurring in the interhemispheric fissure closely related to the corpus callosum, which is often abnormal. It is the most common location for an intracranial lipoma.
On imaging, they can be identified in two different morphologies: tubulonodular, ...
Pericardial teratomas are type of primary pericardial tumour. They are usually diagnosed in infants and neonates. As with all teratomas, they are comprised of contain endodermal, mesodermal and neuroectodermal germinal layers. While they are usually benign tumours, they may be life-threatening ...
Perinatal lethal hypophosphatasia (PLH) is the most severe form of hypophosphatasia. If untreated, it is lethal in all cases.
The estimated incidence is at ~1:100,000 live births.
As with all hypophosphatasia cases, this is due to a mutation in chromosome 1q3...
Periosteal reaction in the paediatric population, also known as periostitis in children, is relatively common occurrence and can result from many causes.
The differential diagnosis for multiple bone periostitis include but not limited to the following:
Peripheral primitive neuroectodermal tumours (pPNET) tend to be large and aggressive retroperitoneal tumours.
The imaging characteristics of peripheral PNETs are nonspecific. However, they should be considered in the differential diagnosis of a large, aggressive retroper...
Periventricular leukomalacia (PVL) or white matter injury of prematurity affecting the periventricular zones, and typically results in cavitation and periventricular cyst formation.
It is important to note that both periventricular and subcortical leukomalacia correspond to a continuous diseas...
One of the methods used for grading of periventricular leukomalacia based on sonographic appearances is as:
grade 1: areas of increased periventricular echogenicity without any cyst formation persisting for more than 7 days
grade 2: the echogenicity has resolved into small periventricular cyst...
Perkin line is a line drawn perpendicular to Hilgenreiner line, intersecting the lateral most aspect of the acetabular roof.
The upper femoral epiphysis should be seen in the inferomedial quadrant: it should lie below Hilgenreiner line, and medial to Perkin line. If the nucleus of the femoral ...
Persistent hyperplastic primary vitreous (PHPV), also known as the persistent fetal vasculature, refers to a rare congenital developmental malformation of the eye.
Clinically, this condition usually manifests as unilateral or bilateral leucocoria. Patients may also have p...
The most common cause of pulmonary hypertension in newborns is persistent pulmonary hypertension of the newborn (PPHN). It occurs in term or late preterms infants, where the fetal shunts persist after birth and fail to close. It falls under group 1.5 of the Dana Point classification system of pu...
A persistent right umbilical vein (PRUV) is an uncommon vascular anomaly which is often detected in utero.
The estimated prevalence is ~2 per 1000 births 1,2.
In the normal situation, the right umbilical vein begins to obliterate in the ~4th week of gestation and disap...
Perthes disease, also known as Legg-Calvé-Perthes disease, refers to idiopathic osteonecrosis of the femoral epiphysis seen in children. It should not be confused with Perthes lesion of the shoulder.
It is a diagnosis of exclusion and other causes of osteonecrosis (including sickle cell disease...
This is a basic article for medical students and other non-radiologists
Perthes disease is the name given to idiopathic AVN (avascular necrosis) of the femoral epiphysis in children. It most often occurs in children around the age of 5-6 years and is one of the common considerations when childr...
Pertussis, also known as whooping cough is a highly contagious, acute respiratory illness that is caused by the gram-negative bacterium Bordetella pertussis.
The incidence of pertussis in children has dramatically decreased since the introduction of pertussis vaccination. However,...
PHACE syndrome, also known as cutaneous haemangioma–vascular complex syndrome or Pascual-Castroviejo type II syndrome, is a phakomatosis that comprises of:
P: posterior fossa malformations (e.g. Dandy-Walker malformation)
A: arterial anomalies
C: coarctation of the aorta and ...
Phenylketonuria (PKU) is an inborn error of metabolism resulting from abnormal metabolism of phenylalanine. If untreated, patients can develop central nervous system impairment.
PKU is inherited as an autosomal recessive disorder with an incidence of 1 in 10,000. It is more commo...
Phocomelia is an extremely rare congenital skeletal disorder that characteristically affects the limbs. It can affect either the upper limbs or lower limbs or both. Phocomelia is also a descriptive term to describe the characteristic limb anomalies occurring with its associated conditions.
Physeal bars are interruptions of the normal growth plate cartilage, due to the formation of a bony or fibrous bridge between the epiphysis and metaphysis. Left untreated, physeal bars can cause abnormal bone angulation or limb length discrepancies.
Physeal bars are not ...
Physeal fractures (also called Salter-Harris fractures) are important childhood fractures that involve the physeal plate. They are relatively common and important to differentiate from other injuries because the involvement of the physis (growth plate) may cause premature closure resulting in li...
Pilocytic astrocytomas, also known as juvenile pilocytic astrocytomas, are low-grade, relatively well-defined astrocytomas that tend to occur in young patients. They are considered WHO grade I tumours in the current (2016) WHO classification of CNS tumours and correspondingly have a relatively g...
Ping pong skull fracture or pond skull fracture refers to a depressed skull fracture of the infant skull caused by inner buckling of the calvarium. It is seen in newborns because of the soft and resilient nature of their bones (like greenstick fractures of long bones) and the fracture line is no...
Pink tetralogy of Fallot refers to a tetralogy of Fallot in which the degree of right ventricular outflow obstruction is minimal, resulting no significant right to left shunt, and therefore no cyanosis. Symptoms are mild and presentation may be delayed, even into adulthood.
Plagiocephaly refers to a type of craniosynostosis in which there is asymmetric premature closure of the coronal and/or lambdoid sutures. It can either involve single or asymmetric multiple sutures. Premature coronal suture closure is associated with the Harlequin eye deformity.
History and ety...
Platyspondyly is a radiographic feature and refers to flattened vertebral bodies throughout the axial skeleton.
Platyspondyly can be feature of many conditions which include:
severe Gaucher disease 1
Pleurisy (or pleuritis) refers to the disease entity characterised by inflammation of the pleura. It classically presents as pleuritic pain.
Pleurisy is often used by medical professionals and laypeople both to refer to the inflammation of the pleura and also the symptoms. Strictl...
Pleuropulmonary blastomas (PPB) are a rare, variably aggressive, childhood primary intrathoracic malignancy. In up to 25% of cases, the mass can be extrapulmonary with attachment to the parietal pleura.
PPB is encountered in childhood, mostly in the first years of life (90% in th...
Pneumatosis coli is a descriptive sign presenting radiographically as intramural gas limited to the colonic wall.
There are different terminologies in the medical literature, such as pneumatosis intestinalis, pneumatosis coli, and pneumatosis cystoides intestinalis. Pneumatosis in...
Polydactyly (less commonly called hyperdactyly) refers to the situation where there are more than the usual number of digits (five) in a hand or foot. It can be broadly classified as:
pre-axial polydactyly: extra digit(s) towards the thumb/hallux (radially)
post-axial polydactyly: extra digit(...
Polymicrogyria is one of many malformations of cortical development (see classification system for cortical malformations), and along with grey matter heterotopias, falls under a bewildering group of conditions characterised by abnormalities both in migration of neurons to the cortex and abnorma...
Porencephaly is a rare congenital disorder that results in cystic degeneration and encephalomalacia and the formation of porencephalic cysts. The term is used variably among radiologists with its broadest definition being a cleft or cystic cavity within the brain 9, and its more narrow definitio...
Positional plagiocephaly, also known as deformational plagiocephaly, refers to a calvarial deformation that results from external pressure after birth when an infant is consistently placed in the same position for rest and sleep. It can be marked in very premature infants, whose heads become fla...
Post-axial polydactyly refers to polydactyly where the additional digit is on the ulnar margin of the hand, or lateral to the 5th toe.
Post-axial polydactyly is more common than pre-axial polydactyly, with an estimated incidence of 1 in 3000.
The posterior fontanelle or occipital fontanelle (or fontanel) is the triangular soft membranous gap at the junction of the lambdoid and sagittal sutures. It persists until approximately 3 months after birth, after which it is known as the lambda. It can be used as an additional sonographic wind...
Posterior fossa astrocytomas, those arising either from the cerebellum or from the brainstem are most frequently seen in children. Approximately 60% of all paediatric astrocytomas are found in the posterior fossa (20% brainstem, 40% cerebellum).
Many types of astrocytoma are found in the poster...
Posterior urethral valves (PUVs), also referred as congenital obstructing posterior urethral membranes (COPUM), are the most common congenital obstructive lesion of the urethra and a common cause of obstructive uropathy in infancy.
Posterior urethral valves are congenital and only...
The Potter sequence is a constellation of findings demonstrated postnatally as a consequence of severe, prolonged oligohydramnios in utero.
It consists of:
pulmonary hypoplasia: often severe and incompatible with life
growth restriction (IUGR)
abnormal facies (Potter f...
A helpful mnemonic to remember the common clinical features of Potter syndrome:
P: pulmonary hypoplasia
T: twisted skin (wrinkly skin)
T: twisted face (Potter facies: low set ears, retrognathia, hypertelorism)
E: extremity deformities (limb deformities: club hands...
Pott puffy tumour refers to a non-neoplastic complication of acute sinusitis. It is characterised by a primarily subgaleal collection, subperiosteal abscess, and osteomyelitis. It is usually related to the frontal sinus but is sometimes secondary to mastoid pathology.
Rarer aetiologies include ...
A Pott shunt is a form of palliative surgery performed in patients with tetralogy of Fallot prior to the ability to repair the defect. It consists of a shunt formed between the descending thoracic aorta and the left pulmonary artery.
This does not relieve the right ventricular outflow obstructi...
Prader-Willi syndrome (PWS) is a rare genetic disorder. It is the most common cause of obesity caused by a genetic syndrome and is primarily characterised by:
sexual infancy: hypogonadism
there usually morbid obesity resulting from hyperphagia is amplified by decre...
Preauricular sinuses are common congenital abnormalities that are typically small blind-ended openings near the ascending limb of the helix. These can be a simple pit or have a sinus tract and/or cystic component.
They are most common in East Asian populations with an incidence of...
Pre-axial polydactyly refers to polydactyly where the additional digit is towards the first digit of the hand (radial side) or foot (medially).
Pre-axial polydactyly is less common than post-axial polydactyly, with an estimated incidence of 1 in 7000.
Premature closure of a growth plate subsequently results in a shortened bone, which can occur in a number of situations.
juvenile chronic arthritis
juvenile rheumatoid arthritis
Prenatal onset infantile cortical hyperostosis is a rare variant of infantile cortical hyperostosis, however, it is a more severe and lethal form and newborns die early postnatally.
Both sporadic and autosomal recessive inheritance have been suggested. A missense mutation in the gene...
Primary ciliary dyskinesia, also known as immotile cilia syndrome, is the result of a congenital defect in the ultrastructure of cilia that renders them incapable of normal movement. It is associated with a number of anatomic and functional abnormalities.
Primary ciliary dyskinesi...
Paediatric primary lung tumours are rare in children however they must be distinguished from locally aggressive inflammatory conditions and benign disease. 1
Primary lung tumours in the neonates and infants include:
pleuropulmonary blastoma (PPB)
infantile fibrosarcoma of the lung
Primitive neuroectodermal tumours (or CNS PNET) were considered aggressive neoplasms of the brain, most frequently encountered in the paediatric population. Importantly, the term no longer appears in the current WHO classification of CNS tumours 11-12.
Please refer to embryonal tumours with mu...
Propionic acidaemia is a rare organic acidaemia caused by a deficiency in the enzyme propionyl coenzyme A carboxylase.
Propionic acidaemia has an incidence of around 1 in 150,000 in the general population 1.
Around 80% of children with propionic acidaemi...
Proteus syndrome is a rare congenital, multisystemic, hamartomatous condition characterised by asymmetrical overgrowth of almost any part of the body and a broad spectrum of manifestations. It can affect tissue from any germinal layer. It is suspected to be a genetic condition, but a particular ...
Proximal femoral focal deficiency is a congenital partial absence of the proximal end of the femur with shortening of the entire lower limb. The diagnosis and classification have been based mainly on plain radiograph findings. This method does not permit definite classification during the first ...
A proximal radio-ulnar synostosis is an upper limb skeletal malformation characterised by bony fusion at the proximal aspect of the radius and ulna. Of the radio-ulnar synostoses, the proximal third is considered the most common site.
It is often congenital but can rarely result fol...
Prune belly syndrome, also known as Eagle Barrett syndrome 3 or triad syndrome, is a rare anomaly comprising a specific constellation of features. It consists of three major findings:
gross ureteric dilatation
anterior abdominal wall underdevelopment (resulting in the "prune belly" appearance)...
A pseudocyst is an abnormal fluid-filled cavity which is not lined by epithelium. It is this fact that distinguishes it pathologically from a cyst, which is lined by epithelium.
Examples of pseudocysts are:
pseudocysts of the germinal matrix
Pseudocysts of the germinal matrix can be present at birth in both pre-term and full-term infants and may be due to a variety of pathologic disorders, frequently occur following haemorrhage, but they are also found incidentally in otherwise normal infants.
They are defined as pseudocysts becaus...
A pseudosinus tract is a normal fibrous cord extending from the coccyx to an overlying sacral dimple. These have no associated mass and contain no fluid (if CSF drainage is occurring via the sacral dimple, then a true dorsal dermal sinus should be considered).
Pseudosubluxation of the cervical spine is the physiological anterior displacement of C2 on C3 in children. It is common in children <7 years, and less often present in older children. Less often it is seen at C3 on C4. It is more pronounced in flexion and is of clinical significance as it can b...
Pulled elbow (also known as nursemaid's elbow) is a subluxation of the radial head into the annular ligament, which usually spontaneously or easily reduces and rarely demonstrates abnormal radiographic features. It should be distinguished from dislocation of the radial head.
Pulmonary aplasia is a rare congenital pathology in which there is unilateral or bilateral absence of lung tissue. It is distinguished from pulmonary agenesis, although similar, the main difference being that there is a short-blind ending bronchus in aplasia 3.
It is usually unilateral, as bila...
Pulmonary artery atresia (or sometimes known as pulmonary atresia) is a congenital cardiovascular anomaly in which there is complete disruption between the right ventricular outflow tract (RVOT) and the pulmonary trunk.
The estimated incidence is 1 in 10,000 births.
Pulmonary atresia with intact interventricular septum (PA-IVS) is a subtype of pulmonary atresia that presents as cyanotic congenital heart disease.
PA-IVS is the combination of obstruction of the pulmonary outflow tract from pulmonary valve atresia without a ventricular septal defe...
Pulmonary hypoplasia (PH) refers to deficient or incomplete development of parts of the lung. It can develop as a result of a number of other in utero anomalies.
The true prevalence is not well known (1.4% of all births according to Knox et al. 13), but in cases of premature ruptu...
Pulmonary interstitial emphysema (PIE) refers to the abnormal location of air within the pulmonary interstitium and lymphatics usually due to positive pressure ventilation. It typically results from rupture of overdistended alveoli following barotrauma in infants with hyaline membrane disease. I...
Pulmonary lymphangiectasia (PL) refers to a rare, fatal congenital abnormality of the lungs characterised by grossly dilated lymphatic channels in the sub pleural, interlobar, perivascular and peribronchial areas 3.
It is divided into two main types 1:
cardiac-associated lymphangiectasia (seco...
Pulmonary plethora is a term used to describe the appearances of increased pulmonary perfusion on chest radiographs. It is commonly used in paediatric radiology.
Usually a left-to-right shunt of 2:1 is required for pulmonary plethora to occur 2,3. Increased pulmonary perfusion occur...
Pulmonary sequestration, also called accessory lung, refers to the aberrant formation of segmental lung tissue that has no connection with the bronchial tree or pulmonary arteries. It is a bronchopulmonary foregut malformation (BPFM).
There are two types:
intralobar sequestration (ILS)
Extralobar pulmonary sequestration (ELS) is a subtype of pulmonary sequestration, the other type being intralobar pulmonary sequestration (ILS).
It is usually encountered in infants, most being diagnosed before six months. It is more common in male (M:F 4:1).
Intralobar pulmonary sequestration (ILS) is a subtype of pulmonary sequestration.
Patients usually present before the third decade with recurrent infection.
It is the commoner type of pulmonary sequestration (four times commoner than extralobar sequestration),...