Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
16,918 results
Article
Aortic valve
The aortic valve (AV) is one of the four cardiac valves and one of two semilunar valves (along with the pulmonary valve). It allows blood to exit the left ventricle (LV) during systole by opening, and during diastole it stops blood exiting by closing.
Gross anatomy
The valve has left, right, ...
Article
Mitral valve
The mitral valve (MV) (or bicuspid valve) is one of the four cardiac valves. It is the atrioventricular valve that allows blood to flow from the left atrium to the left ventricle. It opens during diastole and closes during systole.
Gross anatomy
The valve has anterior and posterior leaflets, ...
Article
Dandy-Walker continuum
Dandy-Walker continuum, also referred to as Dandy-Walker spectrum or Dandy-Walker complex, corresponds to a group of disorders believed to represent a continuum spectrum of posterior fossa malformations, characterized by inferior vermian hypoplasia and incomplete formation of the fourth ventricl...
Article
Echogenic intracardiac focus
Echogenic intracardiac focus (EIF) is a relatively common sonographic observation that may be present on an antenatal ultrasound scan.
Epidemiology
They are thought to be present in ~4-5% of karyotypically normal fetuses. They may be more common in the Asian population 5.
Associations
trisom...
Article
Coronary arteries
The coronary arteries arise from the aortic sinuses immediately distal (superior) to the aortic valve and supply the myocardium with oxygenated blood. The arteries branch to encircle the heart, covering its surface with a lacy network, perhaps resembling a slightly crooked crown.
Gross anatomy
...
Article
Heart
The heart is a hollow, muscular organ of the middle mediastinum, designed to pump oxygenated blood around the systemic circulation and deoxygenated blood around the pulmonary circulation.
Gross anatomy
The heart has a somewhat pyramidal form and is enclosed by the pericardium. Its base (roughl...
Article
Magnetic susceptibility
Magnetic susceptibility is the ability of external magnetic fields to affect the nuclei of an atom. This may also be thought of as the “magnetisability” of a material, or the extent to which a material becomes magnetized when placed in an external magnetic field.
Magnetic susceptibility is rela...
Article
Gastric varix
Gastric varices are an important portosystemic collateral pathway, occurring in ~20% of patients with portal hypertension. They are considered distinct from esophageal varices in that they have a propensity to hemorrhage at comparatively lower portal pressures 1, and are also associated with hig...
Article
Classification system for malformations of cortical development
The classification system for malformations of cortical development organizes myriad conditions into one of three major underlying groups according to the main underlying mechanism:
group I: abnormal cell proliferation or apoptosis
group II: abnormal neuronal migration
group III: abnormal cor...
Article
Focal cortical dysplasia
Focal cortical dysplasias (FCD) represent a heterogeneous group of disorders of cortical formation, which may demonstrate both architectural and proliferative features. They are one of the most common causes of epilepsy and can be associated with hippocampal sclerosis and cortical glioneuronal n...
Article
Meningioma
Meningiomas are extra-axial tumors and represent the most common tumor of the meninges. They are a non-glial neoplasm that originates from the meningocytes or arachnoid cap cells of the meninges and are located anywhere that meninges are found, and in some places where only rest cells are presum...
Article
Systemic lupus erythematosus
Systemic lupus erythematosus (SLE) is a complex autoimmune disease with multisystem involvement. Although abnormalities in almost every aspect of the immune system have been found, the key defect is thought to result from a loss of self-tolerance to autoantigens.
Epidemiology
There is a strong...
Article
Splenic calcification
Splenic calcifications can occur in various shapes and forms and can arise from a myriad of etiological factors.
The usual calcifications observed in radiographs are the multiple, miliary form presenting as numerous small rounded densities averaging from three to five millimeters in diameter wh...
Article
Intraventricular meningioma
Intraventricular meningiomas are rare tumors usually encountered in adults and are somewhat distinct from the far more common extra-ventricular meningioma.
On imaging, they classically present as vividly enhancing solid mass at the trigone of the lateral ventricles.
Epidemiology
Intraventricu...
Article
Optic pathway glioma
Optic pathway gliomas are relatively uncommon tumors, with a variable clinical course and usually seen in the setting of neurofibromatosis type I (NF1). Histologically the majority are pilocytic astrocytomas.
They are characterized by imaging by an enlarged optic nerve seen either on CT or MRI....
Article
Tension pneumocephalus
Tension pneumocephalus is a neurosurgical emergency that occurs when subdural air causes a mass effect over the underlying brain parenchyma, often from a ball-valve mechanism causing one-way entry of air into the subdural space 1.
Clinical presentation
Tension pneumocephalus has a varied clini...
Article
Mount Fuji sign
Mount Fuji sign is seen on cross-sectional imaging and is indicative of a tension pneumocephalus.
The sign refers to the presence of gas (pneumocephalus) between the tips of the frontal lobes with a heaped-up appearance giving the silhouette-like appearance of Mount Fuji 1-3. It suggests that ...
Article
Skull base meningioma
Skull base meningiomas can be located at the olfactory groove, tuberculum sella, sphenoid ridge, petroclival region, foramen magnum and jugular foramen 1.
Clinical presentation
Similar to typical meningiomas, they are slowly growing and usually asymptomatic. Apart from headache, they can pre...
Article
Cerebellopontine angle mass (mnemonic)
Mnemonics for the common cerebellopontine angle masses include:
AMEN or MEAN
SAME
ANGLES
Mnemonics
AMEN/MEAN
A: acoustic neuroma (a.k.a. vestibular schwannoma) (~80%)
M: meningioma (~10%)
E: ependymoma (~5%)
N: neuroepithelial cyst (arachnoid/epidermoid) (~5%)
SAME
S: schwannoma
ves...
Article
Air bubble sign (tension pneumocephalus)
The air bubble sign is seen on CT of the brain and represents multiple small foci of air within the subarachnoid space, especially the Sylvian fissure.1
Although described as a sign of tension pneumocephalus it is also seen in pneumocephalus without elevated pressures.2
It should not be confus...
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