Articles
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16,918 results
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
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
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...
Article
Melanotic meningioma
Melanotic meningiomas are a rare histological variant of metaplastic meningioma. This should not be confused with anaplastic meningiomas (grade 3) that may resemble malignant meningioma.
Epidemiology
As only several dozen cases have been reported in the literature, no significant difference in...
Article
Fibrous meningioma
Fibrous meningiomas (also known as fibroblastic meningiomas) are the second most common histological subtype of meningioma, found in ~50% of all meningiomas, usually along with meningothelial histology (40%) or in isolation (7%). They are, for some reason, the most common intraventricular mening...
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
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
Peaking sign (tension pneumocephalus)
The peaking sign is seen in cross-sectional imaging of the brain and is suggestive of a tension pneumocephalus. It represents the frontal lobes being pushed together forming a peak in the midline giving a heaped up appearance surrounded by air 1. Later, as the frontal lobes become separated they...
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
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
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
Diffuse brainstem glioma (historical)
Diffuse brainstem gliomas or diffuse intrinsic pontine gliomas was a term used to describe infiltrating astrocytomas arising in the brainstem, usually in children. It is no longer recognized as a distinct entity, removed from the 2016 update to the WHO classification of CNS tumors replaced by a ...
Article
Diffuse midline glioma, H3 K27-altered
Diffuse midline glioma, H3 K27-altered is a specific entity that represents the majority of diffuse intrinsic pontine gliomas, although identical tumors are also found elsewhere in the midline (e.g. brainstem, spinal cord and thalamus) 1. They are aggressive tumors with a poor prognosis and are ...
Article
Mature cystic ovarian teratoma
Ovarian dermoid cyst and mature cystic ovarian teratoma are terms often used interchangeably to refer to the most common ovarian neoplasm. These slow-growing tumors contain elements from multiple germ cell layers and can be assessed with ultrasound or MRI.
Terminology
Although they have very ...
Article
Asherman syndrome
Asherman syndrome, also known as uterine synechiae, is a condition characterized by the formation of intrauterine adhesions, which are usually sequela from injury to the endometrium and is often associated with infertility.
Epidemiology
There is a tendency for the condition to develop soon aft...
Article
Bottom of sulcus focal cortical dysplasia
Bottom of sulcus focal cortical dysplasia, or simply bottom of sulcus dysplasia, refers to a highly epileptogenic and localized focal cortical dysplasia that is anatomically restricted to, and maximal at, the bottom of a cortical sulcus.
Epidemiology
The true incidence is not known given botto...
Article
Shoulder dislocation (summary)
This is a basic article for medical students and other non-radiologists
Shoulder dislocation is defined as the humeral head moving out of the glenoid fossa. It is almost always traumatic in etiology.
Reference article
This is a summary article. For more information, you can read a more in-dep...
Article
Anterior shoulder dislocation
Anterior shoulder dislocation is by far the commonest type of dislocation and usually results from forced abduction, external rotation and extension 1.
Epidemiology
Broadly speaking, anterior shoulder dislocations occur in a bimodal age distribution. The first, and by far the more prevalent a...
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