Items tagged “brain”
17 results found
Article
Developmental venous anomaly
Developmental venous anomaly (DVA), also known as cerebral venous angioma, is a congenital malformation of veins which drain normal brain. They were thought to be rare before cross-sectional imaging but are now recognized as being the most common cerebral vascular malformation, accounting for ~5...
Article
Ependymoma
Ependymomas represent a relatively broad group of glial tumors most often arising from the lining of the ventricles of the brain or the central canal of the spinal cord. They account for ~5% of all neuroepithelial neoplasms, ~10% of all pediatric brain tumors and up to 33% of brain tumors occurr...
Article
Obstructive hydrocephalus
Obstructive hydrocephalus is a term usually used to denote obstructive non-communicating hydrocephalus.
It is actually a term that causes confusion as used in the above sense implies that communicating hydrocephalus does not have an obstruction to CSF flow/absorption; this is not true as the m...
Article
Pituitary apoplexy
Pituitary apoplexy is an acute clinical condition caused by either hemorrhagic or non-hemorrhagic necrosis of the pituitary gland. Although presentation is variable, it typically comprises headache, visual deficits, ophthalmoplegia, and altered mental status. An existing pituitary macroadenoma i...
Article
Subependymoma
Subependymomas are uncommon, benign (WHO grade 1) tumors which are slow-growing and non-invasive. They tend to occur in middle-aged and older individuals and usually identified as an incidental finding.
Terminology
These tumors were previously also known as subependymal astrocytomas, not to b...
Article
Calcarine fissure
The calcarine fissure, or calcarine sulcus, is located on the medial surface of the occipital lobe and divides the visual cortex (a.k.a. calcarine cortex) into two.
The fissure is variable in course (figure 1), but is generally oriented horizontally, anteriorly joining the parieto-occipital fi...
Article
Pituitary region mass with intrinsic high T1 signal
Pituitary region masses with intrinsic high T1 signal, also referred to as suprasellar hotspots, are relatively frequently encountered, and the presence of high T1 signal narrows the differential somewhat.
Differential diagnosis
The differential can be divided by the substance causing the T1 ...
Article
Glutaric aciduria type 1
Glutaric aciduria type 1 is a leukodystrophy that can be subclassified as an organic acidopathy. It has a highly variable clinical presentation, and laboratory investigations are not always diagnostic. Imaging, therefore, has an important role to play as the MRI features can be characteristic.
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Article
White matter tracts
White matter tracts in the brain, also known as white matter fibers, are classified into three categories:
projection fibers
association fibers
commissural fibers
The white matter can be observed well on T1W, T2W and FLAIR sequences. Some white matter tracts are quite well demonstrated espec...
Article
Sandwich sign (Marchiafava-Bignami disease)
The sandwich sign of Marchiafava-Bignami disease has been described for the appearance of the central layers of the corpus callosum which are preferentially involved by this disease.
T2 and FLAIR hyperintensities are seen in the central region of body and splenium of corpus callosum with sparin...
Article
Intracranial tumors (summary)
This is a basic article for medical students and other non-radiologists
Intracranial tumors comprise a heterogeneous group of tumors. In adult patients, the majority represent metastatic disease with a smaller proportion being primary brain tumors. Metastasis to the brain occurs, most commonly,...
Article
Precentral gyrus
The precentral gyrus, also known as the primary motor cortex, is a very important structure involved in executing voluntary motor movements.
Gross anatomy
The precentral gyrus is a diagonally oriented cerebral convolution situated in the posterior portion of the frontal lobe. It is located i...
Article
Premedullary cistern
The premedullary cistern is one of the subarachnoid cerebrospinal fluid cisterns.
Gross anatomy
It extends from the pontomedullary junction above, to the foramen magnum below, between the lower clivus and anterior medulla.
It is separated from the prepontine cistern above by the medial pontom...
Article
CT angiography of the cerebral arteries (protocol)
CT angiography of the cerebral arteries (also known as a CTA carotids or an arch to vertex angiogram) is a non-invasive technique that allows visualization of the internal and external carotid arteries and vertebral arteries and can include just the intracranial compartment or also extend down t...
Article
Superior olivary nucleus
The superior olivary nuclei (or complex, SOC) are a group of nuclei within the pons contributing to the ascending and descending auditory pathways.
Gross anatomy
The superior olivary nuclei are located in the pons, while the inferior olivary nuclei are located in the medulla. It is generally s...
Article
Olive
The olive is the ventral oval prominence in the medulla oblongata which contains the inferior olivary nucleus, implicated in motor co-ordination.
Gross anatomy
The olive is a smooth ovoid prominence just below the pons. It is located in the superior medulla, lateral to the pyramid and ventrola...
Article
Arterial input function
Arterial input function (AIF) is commonly defined as the concentration of the contrast medium in an artery measured over time by placing a region of interest.
Use in MRI and CT
It is important to be precise that on MRI the estimation of the concentration is obtained indirectly from the induced...
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