Osteochondritis dissecans (OCD) is the end result of the aseptic separation of an osteochondral fragment with the gradual fragmentation of the articular surface. It is often associated with intraarticular loose bodies.
Onset is between childhood and middle age, with the majority o...
Osteofibrous dysplasia is a benign fibro-osseous cortical lesion that occurs almost exclusively in the tibia and fibula. It is most commonly seen in the mid-diaphysis of the tibia. Some consider it synonymous with ossifying fibroma because of histological similarities, but it is generally consid...
Osteogenesis imperfecta (OI) refers to a heterogeneous group of congenital, non-sex-linked, genetic disorders of collagen type I production, involving connective tissues and bones.
The hallmark feature of osteogenesis imperfecta is osteoporosis and fragile bones that fracture easily, as well a...
The several forms of osteogenesis imperfecta (OI) have been classified, representing wide variation in appearance and severity, and clinical features vary widely not only between types but within types.
Osteogenesis imperfecta was initially classified by type according to a sche...
Osteoid osteomas are benign bone-forming tumors that typically occur in children (particularly adolescents). They have a characteristic lucent nidus less than 1.5 or 2 cm and surrounding osteosclerotic reaction, which classically causes night pain that is relieved by the use of salicylate analge...
Osteopathia striata with cranial sclerosis (OS-CS) is a clinically separate entity from osteopathia striata (Voorhoeve disease). Bony changes on their own are typically incidental and autosomal dominant, whereas OS-CS is a multisystem, X-linked dominant disorder.
OS-CS is extremel...
Osteopetrosis, also known as Albers-Schönberg disease or marble bone disease, is an uncommon hereditary disorder that results from defective osteoclasts. Bones become sclerotic and thick, but their abnormal structure actually causes them to be weak and brittle.
There are two separate subtypes o...
Osteopoikilosis is a sclerosing bony dysplasia characterized by multiple benign enostoses. It is a rare inherited benign condition incidentally found on skeletal x-rays. Its importance is predominantly in correct diagnosis so that it is not mistaken for pathology.
The bone islands...
Osteoporosis pseudoglioma syndrome is a rare autosomal recessive disease that is characterized by severe osteoporosis and blindness. This disease is frequently mistaken for osteogenesis imperfecta.
This disease is encountered in approximately 1 in 2 million births.
Oxycephaly (also known as turricephaly) is the most severe of the craniosynostoses and results from the premature closure of all sutures.
Characterized by a tower-like skull which may be associated with:
8th cranial nerve lesion
optic nerve compression
Oxygen (chemical symbol O) is one of the basic organic elements, and is a constituent of most of the known organic molecules - and therefore all lifeforms - on earth.
Oxygen is a colourless odorless diatomic gas with an atomic number 8 and atomic weight 15.999. It h...
The AP supine abdominal radiograph is a routine view when imaging the pediatric abdomen. This view may be taken alongside the PA erect and lateral decubitus views. As radiation protection is an essential consideration in pediatrics, some departmental protocols may only perform one view (either t...
The horizontal beam lateral radiograph is an additional projection to demonstrate the pediatric abdomen. This view is ideal for neonates as free abdominal gas can be visualized without the neonate being erect. This view is also ideal for children that are unable to move from the supine position ...
The lateral decubitus radiograph is an additional projection for assessing the pediatric abdomen. This view is ideal for displaying free air in the abdomen and/or if the patient is unable to lie supine 1. As radiation dose is an important consideration for pediatric imaging, the lateral decubitu...
The PA erect abdominal radiograph is the standard view for assessing air-fluid levels and free air in the pediatric abdomen. This view may be taken alongside the AP supine and lateral decubitus views. As radiation protection is an essential consideration in pediatrics, some departmental protocol...
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)
A number of pediatric cardiovascular procedures are encountered when reporting pediatric imaging. They include:
Blalock-Taussig (BT) shunt
classic: end to side subclavian to ipsilateral pulmonary arterial anastomosis
modified: graft anastomosis
Sano shunt: right ventricle to...
The differential diagnosis of pediatric cervical lesions is commonly encountered in practice, unfortunately, the list is long.
Most lesions tend to be inflammatory 3:
nontuberculous mycobacterial lymphadenitis
The anteroposterior erect chest view is ideal in younger cooperative pediatric patients (approximately 3-7 years old; this age range is only a guide). This chest view examines the lungs, bony thoracic cavity, mediastinum and great vessels.
The AP erect view is often chosen over the PA erect vie...
The horizontal beam pediatric lateral chest view is a modified lateral projection often utilized in populations under the age of 6 months old due to the inability of that patient to independently hold up their head.
There is a body of research that suggest the lateral projection is not required...
The pediatric lateral chest view may be performed as an adjunct to a frontal chest radiograph in cases where there is diagnostic uncertainty. The lateral chest view examines the lungs, bony thoracic cavity, mediastinum, and great vessels. Lateral radiographs can be particularly useful in assessi...
In pediatric imaging, the anteroposterior supine chest x-ray is beneficial for imaging unconscious or uncooperative patients. This view is preferred in infant and neonate imaging, whilst AP erect and PA erect views are ideal for children able to cooperate in sitting or standing 1.
As radiation ...
The clavicle is a unique bone and as such it often displays unique pathology. The following is an attempt to summarize pediatric clavicle abnormalities.
Pediatric bone tumors and tumor-like lesions of the clavicle
majority of clavicular tumors are malignant
Ewing sarcoma (most common)
The pediatric curriculum is one of our curriculum articles and aims to be a collection of articles that represent the core pediatric knowledge.
Topics pertaining to pediatric radiology, including pediatric neuroradiology and fetal radiology, although there will be some cross coverag...
The pediatric cystic renal diseases are a heterogeneous group of conditions defined by the presence of kidney cysts due to hereditary or non-hereditary causes:
isolated simple cyst
cystic renal dysplasia
multicystic dysplastic kidney (MCDK)
obstructive cystic renal dysplasia
Pediatric elbow radiographs are commonly encountered in the emergency department and, when approached in a systematic fashion, are not as difficult to interpret as most people think!
Check that the ossification centers are present and in the correct position. Th...
The posteroanterior hand view for pediatrics is part of a two view series metacarpals, phalanges, carpal bones and distal radioulnar joint.
patient is seated alongside the table
the affected arm if possible is flexed at 90° so the arm and hand can rest on the table
The frog leg lateral view is a special radiographic of the pelvis to evaluate the hip. Some departments will perform this routinely instead of the AP pelvis view to reduce exposure and maintain high diagnostic accuracy 1. Bilateral examination allows for better visualization of the hip joints an...
The pediatric kidneys follow a growth curve. The measurements below are of the longest maximal dimension. Measurements in parentheses are one standard deviation.
0 months 1: female: 4.15 cm (0.35); male: 4.22 cm (0.32)
2 months: 5.28 cm (0.66)
6 months: 6.15 cm (0.67)
10 months: 6.23 cm (0....
The PRETEXT system proposed by the International Childhood Liver Tumors Strategy Group (previously called Société Internationale d’Oncologie Pédiatrique - Epithelial Liver Tumor Study Group - SIOPEL) aims for staging and risk stratification of liver tumors at diagnosis.
It is used to describe ...
Pediatric mediastinal masses are the most common chest masses in children, with the anterior mediastinum being the most common site 1.
As in adults, mediastinal masses are classified depending on anatomical sites:
anterior mediastinal masses
middle mediastinal masses
posterior mediastinal ma...
This classification system based on the embryology and anatomy of the nasal cavity, nasofrontal region, and nasolacrimal apparatus as well as anomalies associated with craniofacial syndromes.2
choanal atresia and stenosis
pyriform aperture stenosis
Pediatric nasal cavity masses can occur within the nose or the nasopharynx. These masses are often found incidentally on imaging but can be readily apparent clinically.
The clinical features of these lesions tend to mimic upper respiratory processes and may result in dela...
The AP pelvis view is a routine view for pediatric patients to examine the hip joints, proximal femora, iliac crests and pelvic ring. The complications of pelvic pathology in pediatrics can significantly affect the child's future, highlighting the importance of proper patient positioning 1.
Tumors of the posterior fossa in children can be remembered using the mnemonic:
The mnemonic is not in order of prevalence; pilocytic astrocytomas are most common.
B: brainstem glioma
A: astrocytoma (pilocytic) (85%)
Pediatric radiography is a subset within general radiography specializing in the radiographic imaging of the pediatric population.
The general principles of radiography remain the same. However, additional consideration needs to be taken into account when determining patient-specific exposure f...
This is a basic article for medical students and other non-radiologists
Pediatric 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 cons...
Pediatric renal tumors 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 tumor: common in older children 1-8 years old
There is a wide range of primary malignancies that results in pediatric skeletal metastases 1:
leukemia: although not truly metastases
clear cell sarcoma: Wilms’ variant
Ewing’s sarcoma: lung metastases much more common
Pediatric urinary tract infections are common and are a source of significant imaging in young children.
Pediatric 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 s...
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 pediatric urinary tract infection (UTI) management, including imaging, prophylaxis and follow-up 1.
This article intend...
Pallister-Hall syndrome displays a wide range of severity and is characterized by hypothalamic hamartomas seen as a mass at the floor of the third ventricle, posterior to the optic chiasm 3,4.
Pallister-Hall syndrome is rare and the exact prevalence is unknown. Patients with posta...
Pallister-Killian syndrome (PKS) is an extremely rare chromosomal anomaly.
It may be more prevalent in births from women of advanced age 4.
Phenotypic expression can significantly vary from multiple anomalies resulting in perinatal death to the more charact...
Pancreatoblastomas are rare pediatric tumors 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 age ...
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 it 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 s...
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 hemangiomas are the most common parotid tumor of childhood. They usually run a characteristically benign course.
The median age at diagnosis is 4 months 1. There is a female preponderance with a male: female ratio of 1:3.
Presents as an en...
Patau syndrome (also known as trisomy 13) is considered the 3rd commonest autosomal trisomy.
Patau syndrome along with Down syndrome (trisomy 21) and Edward syndrome (trisomy 18) are the only three trisomies to be compatible with extrauterine life. However, few infants live more than a few days...
Patellar sleeve fractures (also commonly, patellar sleeve avulsion fracture) represent chondral or osteochondral avulsion injury commonly at the inferior pole of the patella (including cartilage from the articular surface, as well as periosteum and cartilage over the dorsal surface).
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 ischemic 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 (Pediatric 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 pediatric algorithm predicts likelihood of the abo...
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 characterized 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 ...
The posteroanterior erect chest view is often performed in older pediatric patients; when the patient is able to cooperate with sitting or standing erect. This chest view examines the lungs, bony thoracic cavity, mediastinum and great vessels.
The PA erect view is often chosen over the AP erect...
Pediatric cystic nephromas, previously known as multilocular cystic nephromas, are rare benign renal neoplasms occurring in children. As of the 2016 WHO classification, they are considered distinct from adult cystic nephromas 1,2.
Evolving terminology regarding cystic nephromas and...
Pelvic osteotomy relates to an orthopedic treatment for developmental acetabular dysplasia of the hip.
The main purpose of pelvic osteotomy is the prevention of early degenerative changes by stabilization of the hip and redistribution of joint loading. It is obtained by surgical reshaping/remod...
Hip surveillance radiographs are part of a concerted effort to monitor and enable early detection of hip displacement in patients with cerebral palsy or neuromuscular disorders. The radiographs consist of a modified AP pelvis in which the patient's legs are in a neutral position, with the patell...
The radiography of the pelvis in the pediatric patient varies greatly from the adult examination; particularly as specialized techniques are often required to immobilize the patient. To avoid future mobility and pain complications, it is essential to treat fractures and correct developmental pat...
PELVIS or LUMBAR syndrome is the combination of pelvic hemangiomas 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 obstructive uropathy. It can be congenital or acquired with a congenital PUJ obstruction being one of the commonest causes of antenatal hydronephrosis.
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 classic four features with the addition of an atrial septal defect or patent ductus arteriosus:
ventricular septal defect (VSD)
right ventricular outlfow tract narrowing or complete obstruction
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.
Pericallosal lipomas are rare, found in only 1 in 2,500 to 1 in 25,...
Pericardial teratomas are type of primary pericardial tumor. 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 tumors, they may be life-threatening du...
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 pediatric 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 tumors (pPNET) tend to be large and aggressive retroperitoneal tumors.
The imaging characteristics of peripheral PNETs are nonspecific. However, they should be considered in the differential diagnosis of a large, aggressive retroperit...
Periventricular leukomalacia (PVL), or white matter injury of prematurity affecting the periventricular zones, typically results in cavitation and periventricular cyst formation.
It is important to note that both periventricular and subcortical leukomalacia corresponds to a continuous disease ...
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 ...
Peroxisomal acyl-CoA oxidase deficiency, also known as pseudo-neonatal adrenoleukodystrophy or just pseudoadrenoleukodystrophy, is a very rare autosomal recessive inborn error of metabolism due to deficiency of the enzyme Acyl-Coa oxidase (encoded by ACOX1 gene, 17q25.1) that results in the accu...
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,...
Pfeiffer syndrome (also known as type V acrocephalosyndactyly) is characterized by skull and limb abnormalities.
It affects about 1 in 100,000 births
PHACE syndrome, also known as cutaneous hemangioma–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 ca...
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 arrest refers to the disturbance or complete cessation of normal growth of skeletally immature bone at the physeal growth plate due to the latter's premature closure
Physeal arrests can be either complete 10, i.e. premature closure of the entire physeal growth plate, or ...
Physeal fractures (also called Salter-Harris fractures) are important childhood fractures that involve the physis (physeal/growth plate). They are relatively common and important to differentiate from other injuries because the involvement of the physis may cause premature closure resulting in l...
Physiologic periostitis describes the normal presence of smooth bilateral diaphyseal periosteal new bone in the humeri, femora or tibiae of infants aged 1 to 6 months. It can be observed in both preterm and term infants. The etiology is unclear but may simply relate to rapid growth.
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 tumors in the current (2016) WHO classification of CNS tumors and correspondingly have a relatively goo...
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.
Pituitary stalk interruption syndrome, also known as pituitary stalk transection syndrome, is a syndrome characterized by an absent or hypoplastic anterior pituitary gland, thin or absent infundibulum, and ectopic posterior pituitary location.
Pituitary stalk interruption syndrome...
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...