Brain Tumor Glossary of Terms

Easily explore the meaning of hundreds of medical terms or words, many directly used in brain tumor-related terminology.

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ECG

A line graph that shows changes in the electrical activity of the heart over time. It is made by an instrument called an electrocardiograph. The graph can show that there are abnormal conditions, such as blocked arteries, changes in electrolytes (particles with electrical charges), and changes in the way electrical currents pass through the heart tissue. Also called EKG and electrocardiogram.

Edema

Swelling caused by excess fluid in body tissues.

EEG

A recording of electrical activity in the brain. It is made by placing electrodes on the scalp (the skin covering the top of the head), and impulses are sent to a special machine. An EEG may be used to diagnose brain and sleep disorders. Also called electroencephalogram.

Effector Cell

A cell that performs a specific function in response to a stimulus; usually used to describe cells in the immune system.

Efficacy

Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.

Electrocardiogram

A line graph that shows changes in the electrical activity of the heart over time. It is made by an instrument called an electrocardiograph. The graph can show that there are abnormal conditions, such as blocked arteries, changes in electrolytes (particles with electrical charges), and changes in the way electrical currents pass through the heart tissue. Also called ECG and EKG.

Electrochemotherapy

Uses electric voltage to carry chemotherapy agents into the brain.

Electromagnetic Radiation

Low-energy radiation that comes from the interaction of electric and magnetic fields. Sources include power lines, electric appliances, radio waves, microwaves, and others. Also called electromagnetic field.

Electron Beam

A stream of electrons (small negatively charged particles found in atoms) that can be used for radiation therapy.

Eligibility Criteria

In clinical trials, requirements that must be met for an individual to be included in a study. These requirements help make sure that patients in a trial are similar to each other in terms of specific factors such as age, type and stage of cancer, general health, and previous treatment. When all participants meet the same eligibility criteria, it gives researchers greater confidence that results of the study are caused by the intervention being tested and not by other factors.

Encephalitis

Encephalitis: Inflammation of the brain. Encephalitis occurs, for example, in 1 in 1,000 cases of measles. It may start (up to 3 weeks) after onset of the measles rash and present with high fever, convulsions, and coma. It usually runs a blessedly short course with full recovery within a week. Or it may eventuate in central nervous system impairment or death. Encephalitis can cause brain damage, which may result in or exacerbate the symptoms of a developmental disorder or mental illness. The form called encephalitis lethargica ("sleeping sickness") results in a set of Parkinson's disease-like symptoms called postencephalitic parkinsonianism. In some cases encephalitis causes death. Treatment of encephalitis must begin as early as possible to avoid potentially serious and life-long effects. Depending on the cause of the inflammation, this may include antibiotics, anti-viral medications, and anti-inflammatory drugs. If brain damage results from encephalitis, therapy (such as physical therapy or cognitive restoration therapy) may help patients regain lost functions.

Encephalopathy

A disorder of the brain that can be caused by disease, injury, drugs, or chemicals.

Endometrioma

1 : a tumor containing endometrial tissue 2 : ENDOMETRIOSIS -- used chiefly of isolated foci of endometrium outside the uterus

Endometriosis

The presence and growth of functioning endometrial tissue in places other than the uterus that often results in severe pain and infertility.

Ependyma

A thin membrane that lines the fluid-filled spaces in the brain and spinal cord. It is made up of a type of glial cell called an ependymal cell.

Ependymal Cell

A cell that forms the lining of the fluid-filled spaces in the brain and spinal cord. It is a type of glial cell.

Ependymal Tumor

A type of brain tumor that begins in cells lining the spinal cord central canal (fluid-filled space down the center) or the ventricles (fluid-filled spaces of the brain). Ependymal tumors may also form in the choroid plexus (tissue in the ventricles that makes cerebrospinal fluid). Also called ependymoma.

Ependymoma

An ependymoma, part of the glial family (glial cells are the supportive cells of the brain), is a rare type of primary brain or spinal cord tumor. It originates in the ependyma, the cells that line the passageways in the brain where cerebrospinal fluid is produced. Also:

* Usually benign and local to an area of the brain, including the ventricles (cavities in the center of the brain)
* Can block the ventricles causing water on the brain
* Sometimes extends to spinal cord
* Can be slow or fast growing
* More than 90 percent occur in children, the third most common pediatric brain tumor

Ependymomas account for approximately three to six percent of central nervous system tumors and two percent of brain tumors.

Epidemiological studies

A branch of medical science that deals with the incidence, distribution, and control of disease in a population.

Excision

Removal by surgery.

Excisional Biopsy

A surgical procedure in which an entire lump or suspicious area is removed for diagnosis. The tissue is then examined under a microscope.

Experimental

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational.

Experimental Drug

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An experimental drug may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called investigational agent and investigational drug.

Exploratory Surgery

Surgery to look inside the body to help make a diagnosis.

External Radiation Therapy

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external-beam radiation therapy.

External-beam Radiation Therapy

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external radiation therapy.