Glossary
Acoustic Neuroma
An acoustic neuroma is a benign tumour located in the hearing
canal. It is sometimes called a vestibular schwannoma or neurinoma.
This tumour grows slowly, and causes damage by pressing on nerves
related to hearing and balance. Larger tumours can also create
pressure on the base of the brain.
Aneurysm
An aneurysm is a weak point in a blood vessel, such as an artery
or vein, which may then blow up like a balloon. The danger is of
the aneurysm bursting and bleeding in the brain, which causes a
stroke. Cerebral aneurysms rarely have symptoms before such
bleeding occurs. Aneurysms are more common in older adults, and
also in smokers.
Angiography
This procedure uses X-rays to produce pictures of arteries
(Arteriogram) or veins (Venogram) by injecting a dye (contrast
material) into the arteries or veins and 'filming' it as it passes
through the blood vessels.
Arteriogram
This is an image of arteries by the injection of dye (contrast
material) into an artery.
Arterio-venous malformations (AVM)
Arteriovenous malformations, AVMs, are abnormal collections of
blood vessels. In normal tissue, blood flows from the heart through
arteries, and then to smaller vessels called capillaries. The
surrounding tissue receives its nourishment from the blood flowing
through the capillaries. In AVMs, the capillaries are absent, so
that the blood flows directly back to the heart, and the tissue
does not receive nourishment. The brain tissue between these
vessels is abnormal.
Chemotherapy
The treatment of disease by chemical agents.
Craniotomy
Any operation which involves removing part of the skull, usually
to operate on the brain.
CSF
Cerebrospinal Fluid. The reservoir of fluid surrounding the
brain and spinal cord and filling the ventricles (cavities within
the brain).
CT
Computed Tomography. Also known as a 'CAT scan' This is a
sophisticated procedure using X-rays to produce computerised images
(slices) through the body.
EEG
Electroencephalography. The recording of electric currents
created in the brain by using electrodes placed on the scalp or
surface of the brain.
Embolization
A technique to treat arteriovenous malformations (AVM's) and
tumours with a large number of vessels by injecting a special glue
to block off the abnormal vessels.
Gamma Knife Surgery (GKS)
This is a term meaning radiosurgery given by a Gamma Knife.
Immunotherapy
A treatment which activates the bodies own immune system to
destroy disease.
Linac Radiosurgery
This is radiosurgery given by a device producing powerful
X-rays, which is normally used to give conventional radiotherapy.
The unit is modified by bolting on a collimator which focuses the
beam down to a few millimetres in width. Treatment with this
equipment tends not to be as accurate as using a Gamma Knife, which
is specifically designed for Radiosurgery.
MRI
Magnetic Resonance imaging. A complex scanner that produces
scans like a CT scanner, but usually with much greater detail. The
scanner uses radio waves in a high strength magnetic field instead
of X-rays to create scans of the body. Images can be produced in
any chosen plane.
MRA
A special type of MRI scan which enables images of the blood
vessels to be made.
PET
Positron Emission Tomography. A special type of X-ray using a
radioactive dye which shows areas of the brain that have a higher
or lower metabolism than normal. It can sometimes be used when an
MRI scan alone is inconclusive. PET is often used in conjunction
with a CT scan (PET/CT).
Radiosurgery
The use of highly focused radiation to destroy tumours or
abnormalities in the brain. Radiosurgery is given in a single
treatment, while with radiotherapy, the treatment is given over
several days. See also Linac Radiosurgery
Radiotherapy
This is the use of radiation to
destroy cancer or other abnormal cells in the body. During
radiotherapy, a significant amount of healthy normal tissue is
irradiated. To reduce the side effects caused by this, the
radiation dose is split into a number of treatments, in theory
enabling the normal healthy tissue to recover before the next
treatment is given.
SPECT
SPECT stands for Single Photon
Emission Computed Tomography. It is a method of scanning a patient
using radioactive dyes, showing areas of the brain where there is
increased metabolic activity. It is less specific than PET, but
more freely available.
