Short limb skeletal dysplasias are skeletal dysplasias which are characterised by limb shortening
Rhizomelic (proximal limb shortening)
particularly type II
Focal gallbladder wall thickening is an imaging finding that includes both benign and malignant aetiologies.
gallbladder carcinoma: look for infiltration into adjacent organs, metastases, lymphadenopathy, bile duct di...
Intramedullary spinal metastases are rare, occurring in ~1% of autopsied cancer patients, and are less common than leptomeningeal metastases.
Intramedullary lesions may result from:
growth along the Virchow-Robin spaces
direct extension from leptomeninges
Oligohydramnios refers to a situation where the amniotic fluid volume is less than expected for gestational age. Often these fetuses have <500 mL of amniotic fluid.
The estimated prevalence can be up to ~6% of pregnancies 4.
The causes of oligohydramnios are pr...
Pulmonary cavities are gas-filled foci of the lung in the centre of a nodule, mass, or area of consolidation. They are usually evident on plain radiography and/or CT. They are typically thick-walled and their walls must be greater than 2-5 mm. They may be filled with gas as well as fluid +/- gas...
Polyhydramnios refers to a situation where the amniotic fluid volume is more than expected for gestational age.
It is generally defined as:
amniotic fluid index (AFI) >25 cm
largest fluid pocket depth (maximal vertical pocket (MVP)) greater than 8 cm 6: although some centres, particularly in ...
A small for dates fetus can result from a number of factors
structural anomalies (syndromes)
fetal Warfarin syndrome
hydantoin embryopathy (Dilantin TM)
A pneumothorax does not display classical signs when a patient is positioned supine for a chest radiograph. Instead, the pneumothorax may be demonstrated by looking for the following signs:
relative lucency of the involved hemithorax
deep, sometimes tongue-like, costophrenic sulcus: deep sulcu...
Pericarditis is defined as inflammation of the pericardium. It is normally found in association with cardiac, thoracic or wider systemic pathology and it is unusual to manifest on its own.
In general, infection is the most common cause of pericarditis. Infection accounts for two-thir...
Cerebellopontine angle (CPA) masses frequently occur, many of which are relatively specific for the region.
Cerebellopontine angle masses can be divided into four groups, based on imaging characteristics:
mass with high T1 signal on MRI
mass with CSF intensity/den...
Non-accidental injuries (NAI) represent both ethical and legal challenges to treating physicians.
Radiologists are often the first to suspect NAI when confronted with particular injury patterns, and a knowledge of these is essential if the opportunity to save a child from future neglect is not ...
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.
Complications of hip joint replacements are common and are essential for the radiologist to be aware in the assessment of the radiographs with hip prostheses. They are many and can occur at various time intervals following the initial surgery:
aseptic loosening: considered to be the most common...
Sacroiliitis (inflammation of the sacroiliac joint) can be a manifestation of a wide range of disease processes. The pattern of involvement is helpful for narrowing down the differential diagnosis.
Usually bilateral and symmetrical
A scalp haematoma usually occurs following an injury at delivery although they are commonly seen with head trauma.
There are three types of haematoma, which are defined by their location within the scalp, particular their location as related to the galea aponeurosis and skull pe...
Cutaneous and subcutaneous metastases are not uncommon, occurring in ~5% (range 0.7-10.4%) of internal malignancies, and representing 2% of skin cancers. The Sister Mary Joseph nodule is a well known cutaneous metastasis.
These metastases can come from haematogenous or lymphatic spre...
Haglund deformity, also known as a pump bump, Bauer bump, or Mulholland deformity, is defined as bony enlargement formed at posterosuperior aspect of the calcaneum. This deformity leads to retrocalcaneal bursitis.
It may result secondary to chronic pressure of rigid shoes.
A surgical sieve is an approach to differential diagnosis that helps, especially when under the pressure of the exam situation. Differentials from the sections of the sieve can be considered in turn, helping to extend the list in a structured way. They include:
Twin pregnancies are the most common multifetal pregnancies.
Multifetal pregnancies account for ~ 1% of all pregnancies but are seen in much higher numbers in populations where in vitro fertilisation (IVF) is a common practice, most of which are twin pregnancies.
Multifocal breast cancer refers to two or more individual breast cancers diagnosed at the same time within the same quadrant of the same breast 1.
Cancer is clearly a huge topic and this page is merely a starting point for what will become a much larger article that links to a myriad of articles and cases. For further information about staging in cancer, see the separate article. Some of the headings are taken from the AJCC cancer staging ...
Medical devices in the abdomen and pelvis are important to be recognised, just like medical devices of the chest. Often we ignore these devices, considering them to be incidental and non-pathological, however it is essential to be aware of potential complications.
A gastric band is a surgically placed device, used to assist in weight loss. It is now the most popular form of bariatric surgery, largely replacing gastric bypass procedures 1.
Performed laparoscopically, a silicone band device is placed around the stomach to reduce its volume. The band is adj...
Fetal intracranial cystic lesions can arise from a number of pathologies, including:
fetal arachnoid cyst
fetal choroid plexus cyst
fetal connatal cyst
fetal porencephalic cyst
fetal interhemispheric cyst
fetal subependymal cyst
dorsal cyst of holoprosencephaly
Small bowel or mesenteric ischaemia may be a life-threatening condition, arising from any one of numerous causes of disturbance of the normal blood flow through the small bowel wall.
It can be divided into acute and chronic forms, with the main underlying aetiologies (each discussed...
Obesity is defined as a body mass index (BMI) greater than 30 kg/m2. It is described as being a "modern epidemic" due to increased rates of metabolic syndrome and other complications in these patients, along with a high and increasing prevalence.
Obesity rates vary around the wor...
Solitary pulmonary nodule (SPN) is defined as a relatively well defined round or oval pulmonary parenchymal lesion equal or smaller than 30 mm in diameter. It is surrounded by pulmonary parenchyma and/or visceral pleura and is not associated with lymphadenopathy, atelectasis, or pneumonia 9.
The differential diagnosis for extratesticular cystic lesions includes:
loop of bowel from an inguinal hernia
Very rarely, a scrotal mesothelioma may present as a cystic mass.
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
Endobronchial metastases are an uncommon form of intrathoracic metastases. They are much less common than intrapulmonary metastases.
The clinical presentation varies and includes:
post-obstructive pneumonitis from distal obstruction
Cervical incompetence refers to a painless spontaneous dilatation of the cervix and is a common cause of second trimester pregnancy failure.
The estimated incidence varies geographically and generally thought to be around 1-1.5% of all pregnancies 1,15.
Hepatisation of the gallbladder is a sonographic entity in which the gallbladder lumen is entirely filled with tumefactive sludge giving the gallbladder a similar appearance to liver parenchyma. It is one of the causes of non-visualisation of the gallbladder on sonography.
In the set...
Erosion of the odontoid peg can result from a number of pathological entities:
rheumatoid arthritis: classic 1,2
systemic lupus erythematosus
calcium pyrophosphate arthropathy (CPPD): relatively common
non-inflammatory arthropathy: osteoar...
Placentomegaly is a term applied to an abnormally enlarged placenta.
It can be associated with a number of maternal and fetal disorders which include:
chronic intrauterine infections
There are numerous causes of urinary bladder diverticula:
Primary (congenital or idiopathic)
Hutch diverticulum (in paraureteral region)
bladder outlet obstruction
bladder neck stenosis
posterior urethral valve
prostatic enlargement (hypertrophy; carcinoma)
Intraventricular metastases are a very rare finding. A few intracranial tumours and some extracranial tumours metastasize to the ventricles. The most common site of intraventricular metastasis is the trigone of the lateral ventricles due to high vascularity of the choroid plexuses. The next most...
Scheuermann disease, also known as juvenile kyphosis, juvenile discogenic disease 11, or vertebral epiphysitis, is a common condition which results in kyphosis of the thoracic or thoracolumbar spine. The diagnosis is usually made on plain film.
occurs in ~5% (range 0.4-8%) of the ...
Hypomyelinating disorders are a heterogeneous subset of white matter disorders characterised by abnormally low amounts of myelination.
In distinction to other myelin disorders, hypomyelination is a permanent deficiency in myelin deposition rather than myelin destruction (i.e. demyelination) or ...
Complications of cranial radiation therapy are fairly common, particularly in long-term survivors, and especially in paediatric patients.
Cranial radiotherapy is used for a variety of brain tumours, either in isolation or in combination with concurrent chemotherapy. Complications from irradiati...
Myelination of the brain during infancy progresses in an orderly and predictable fashion which can be assessed with MRI.
At term (40 weeks corrected gestation) only certain structures are myelinated:
central corticospinal tracts
Right lower lobe collapse has distinctive features, and is usually relatively easily identified. The absence of overlying cardiomediastinal outline makes it easier to appreciate than left lower lobe collapse.
For a general discussion please refer to the article on lobar collapse.
Right middle lobe collapse (or simply termed middle lobe collapse) has distinctive features, but can be subtle on frontal chest radiographs.
For a general discussion please refer to the article on lobar collapse.
It is important to note that of all the lobes, the right middle lobe is the mo...
The differential diagnosis for unilateral testicular lesions is wide-ranging.
seminoma (40-50% of tumours)
non seminomatous germ cell tumours:
testicular epidermoid (teratoma with ectodermal elements only)
Epilepsy is a common neurological disorder that has a varied presentation and requires two or more unprovoked seizures at least 24 hours apart for diagnosis. MRI is the modality of choice for epilepsy, most often investigating for an underlying cause, especially in adults.
An aortic nipple is seen in about 10% of PA chest x-rays on the lateral surface of the aortic arch/aortic knob. It represents the left superior intercostal vein.
When prominent, superior vena cava obstruction should be considered as the left superior intercostal vein serves as a collateral path...
Adrenal lesions cover a broad spectrum from benign to neoplastic entities. Due to increased use of cross-sectional imaging they are frequently detected as incidental lesions ("incidentalomas"). If found incidentally, please refer to the Management of incidental adrenal masses: American College o...
Adrenal haemorrhage can result from a variety of traumatic and non-traumatic causes. When unilateral, it is often clinically silent. In contrast, bilateral adrenal haemorrhage can lead to catastrophic adrenal insufficiency.
The large majority of patients with unilateral a...
Seronegative spondyloarthritides, also known as spondyloarthropathies (SpA), are a group of musculoskeletal syndromes linked by common clinical features and common immunopathologic mechanisms. The subtypes of spondyloarthritis are usually distinguished on the basis of the patient’s history and c...
Skeletal “don’t touch” lesions (also called leave me alone lesions) are so radiographically characteristic lesions that an additional diagnostic tests such as a biopsy are unnecessary and can be frankly misleading and lead to additional unnecessary surgery. Thus a radiologic diagnosis should be ...
Although frequently used as a synonym for calcium pyrophosphate dihydrate deposition disease (CPPD), chondrocalcinosis simply means visible calcification of both hyaline cartilage and fibrocartilage.
It has a reported prevalence of 5-15% 2 and is thought to increase with age.
Exostoses are defined as benign growths of bone extending outwards from the surface of a bone. It can occur in any bone and be triggered by a number of factors. There are a number of examples of exostoses that occur due to local irritant stimuli:
exostosis of the external audit...
Syndactyly refers to a congenital fusion of two or more digits. It may be confined to soft tissue (soft tissue syndactyly / simple syndactyly) or may involve bone (bony syndactyly / complex syndactyly).
The overall estimated incidence is at ~1 per 2,500 to 5,000 live births 6,8. T...
Coccydynia refers to pain in and among the area of the coccyx. It is characterised by coccygeal pain which is typically provocated by pressure. It may remain unclear in origin owing to the unpredictability of the source of pain 1.
No accurate data about the frequency of coccydynia...
Basal ganglia calcification is common and is seen in approximately 1% of all CT scans of the brain, depending on the demographics of the scanned population. It is seen more frequently in older patients and is considered a normal incidental and idiopathic finding in an elderly patient but should ...
Facial palsy refers to the neurological syndrome of facial paralysis. It can result from a broad range of physiological insults to the facial nerve or its central nervous system origins. The most common causes of this is Bell palsy.
While facial palsy refers to the clinical presen...
A simple and popular mnemonic to remember the common suprasellar/parasellar/intrasellar masses is SATCHMO. The more comprehensive list includes:
pituitary adenoma (commonest in the adult population)
Diffuse thickening of the gallbladder wall can occur in a number of situations:
gallbladder empyema 7
xanthogranulomatous cholecystitis 11
postprandial physiological state (pseudothickening)
The differential for peripheral or ring enhancing cerebral lesions includes:
demyelination (incomplete ring)
tumefactive demyelinating lesion (incomplete ring)
Liver tumours, like tumours of any organ, can be classified as primary or secondary.
Liver metastases are by far the most common hepatic malignancy, with many of the most common primaries readily seeding to the liver. This is especially the case with gastrointestinal tract tumours, ...
Multilayered periosteal reaction, also known as a lamellated or onion skin periosteal reaction, demonstrates multiple concentric parallel layers of new bone adjacent to the cortex, reminiscent of the layers on an onion. The layers are thought to be the result of periods of variable growth 2.
Codman triangle is a type of periosteal reaction seen with aggressive bone lesions. With aggressive lesions, the periosteum does not have time to ossify with shells of new bone (e.g. as seen in single layer and multilayered periosteal reaction), so only the edge of the raised periosteum will oss...
Sunburst appearance is a type of periosteal reaction giving the appearance of a sunburst secondary to an aggressive periostitis. It should not be confused with the sunburst sign of meningioma vascularity.
The sunburst appearance occurs when the lesion grows too fast and the periosteum does not...
Solid periosteal pattern is thought to evolve from single layer and multilayered periosteal reactions, forming a solid layer of new bone adjacent to the cortex.
It can be seen in:
Disorganised or complex periosteal reaction has spicules with random orientation and appearance. It can be seen in highly aggressive processes:
malignant fibrous histiocytoma
spindle cell sarcoma
Spiculated periosteal reaction represents spicules of new bone forming along vascular channels and the fibrous bands that anchor tendons to bone (Sharpey fibres). A spiculated periosteal reaction signifies a rapid underlying process that prevents formation of new bone under the raised periosteum...
Single layer periosteal reaction is a uniformly dense, single thin layer of new bone about 1-2 mm from the cortical surface. Passive hyperaemia causes increased osteoblastic activity and production of new bone. It is seen in:
premature infants for up to 6 months
early fracture healing
Conductive hearing loss is caused by a range of developmental, congenital or acquired pathology to the external, middle or inner ear.
Essentially any process that obstructs or disrupts the passage of sound waves through the outer or middle ear can cause conductive hearing loss and th...
There are many complications that can occur following gastric banding. It is helpful to divide these into early and late post-surgical complications.
Although the exact mode of presentation can vary depending on the underlying complication common modes of presentation tha...
Cystic lung disease is an umbrella term used to group the conditions coursing with multiple lung cysts.
A lung cyst is a gas-filled structure with perceptible wall typically 1 mm in thickness but can be up to 4 mm. The diameter of a lung cyst is usually <1 cm. By conventional defini...
Tubulinopathy refers to a wide spectrum of cortical malformations that result from defects in genes encoding the tubulin protein that regulates neuronal migration during brain development.
Some series report a high prevalence of seizures during infancy which may the initi...
Solitary lucent lesion of the skull is a relatively frequent finding. The differential is heavily influenced by the patient's age.
renal cell cancer
epidermoid and dermoid
Fluid in the endometrial cavity can result from a number of causes if excessive and associated with distension.
There are essentially three types of fluid:
hydrometra: simple fluid
haematometra: haemorrhagic content / clot
normal (i.e. physiological...
A very wide range of lesions can occur in and around the sacrum.
primary sacral tumours
sacral chordoma: most common primary sacral tumour 1
Ewing sarcoma / pPNET
osteosarcoma: often arises from Paget's disease in this location
The differential diagnosis for a posterior mediastinal mass includes:
neurogenic tumours - most common
nerve sheath tumours
malignant peripheral nerve sheath tumour
parasymphathetic ganglion tumours
Bone within a bone is a descriptive term applied to bones that appear to have another bone within them. There are numerous causes including:
thoracic and lumbar vertebrae (neonates and infants)
growth recovery lines (after infancy)
cortical splitting and new periostitis
sickle cell d...
Accurately determining whether hydrocephalus or atrophy (compensatory enlargement of the CSF spaces) is the cause of ventriculomegaly can be, at times, challenging in image interpretation.
Features that favour hydrocephalus include:
dilatation of the temporal horns
Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular septal thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.
Toxoplasmosis and lymphoma are frequently differential diagnoses in patients with HIV/AIDS and as treatment is substantially different distinguishing the two is important.
In many instances, the imaging appearance is classic and differentiation is not problematic; however, in 50-80% of cases, ...
Solitary sclerotic bone lesion with a lucent centre have a number of differentials:
Both neuroblastoma and Wilms tumour occur in early childhood and typically present as large abdominal masses closely related to the kidneys. Distinguishing between the two is important, and a number of features are helpful.
calcification very common: 90%
encases vascular structu...
The words heterogeneous and heterogenous are commonly used in radiological and medical description and reporting. They are often incorrectly used interchangeably, as they have significantly different meanings.
Heterogeneous refers to a structure with dissimilar components or elements. For examp...
Pulmonary blebs are small subpleural thin walled air containing spaces, not larger than 1-2 cm in diameter. Their walls are less than 1 mm thick. If they rupture, they allow air to escape into pleural space resulting in a spontaneous pneumothorax.
Blebs are a very common finding ...
Epiphyseal lesions comprise tumours and other pathologies that occur around the epiphysis and any epiphyseal equivalent bone.
Common differential diagnoses include 2-4:
chondroblastoma: rare epiphyseal tumour found in young adults; it usually does not extend into the me...
Neurofibromatoses (NF) comprise a number of clinically and genetically distinct inherited conditions that carry a high risk of tumour formation. They fall under the wider classification of phakomatoses. The tumours particularly involve the central and peripheral nervous systems:
There are a number of lesions that appear hyperechoic on ultrasound. Such lesions can be either completely or partly hyperechoic and include both benign and malignant entities.
fat containing breast lesions
lipoma of the breast
fibroadenolipoma (hamartoma) of the breast
Storage disorders comprise a bewildering collection of inherited metabolic conditions which share the accumulation of a metabolite within various cells in the body due to dysfunction of specific enzymes or transport proteins. Accumulation of metabolites eventually results in cellular and/or orga...
Primary peritoneal neoplasms comprise an uncommon group of heterogenous entities.
The list includes:
primary (malignant) peritoneal mesothelioma
primary peritoneal multicystic mesothelioma
primary peritoneal well-differentiated papillary mesothelioma
Papillary lesions of the breast comprise a wide group and range from benign to malignant.
They develop as tufts of epithelium with a ﬁbrovascular core that arborize into branching papillae and protrude into the duct lumen.
papilloma of breast / intraductal papilloma of the b...
Mitral valve disease (MVD) mostly comprises two main functional abnormalities, which can occur in isolation or in combination:
In addition, other pathologies that affect the mitral valve include:
mitral valve prolapse
mitral annular calcification
Sclerotic or blastic bone metastases can arise from a number of different primary malignancies including 1-5:
prostate carcinoma (most common)
breast carcinoma (may be mixed)
transitional cell carcinoma (TCC)
mucinous adenocarcinoma of the gastroint...
Hyperattenuating paranasal sinus opacification can arise in a number of situations:
fungal sinus disease
acute haemorrhage into sinus (haemosinus)
In some situations can consider early calcification within the sinus.
Ventriculoperitoneal (VP) shunts are a device used to shunt cerebrospinal fluid in the treatment of hydrocephalus.
As the name suggests, a catheter is placed with its tip in the ventricle. The external portion of the catheter is connected to a valve that regulates the flow of CSF based on a pre...
Osteoporosis circumscripta cranii (also known as osteolysis circumscripta) refers to discrete radiolucent regions of the skull on plain radiographs. They are often seen in context of the lytic (incipient-active) phase of Paget disease of the skull, but may be observed in other circumstances as w...