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Glossary of terms

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echocardiogram
This test uses a small transducer that produces high-frequency sound waves, which create detailed images of the heart.

ectopic pregnancy
A pregnancy in which the fetus develops outside the uterus, typically in a fallopian tube.

edema
An accumulation of an excessive amount of watery fluid in cells, tissues, or serous cavities.

electrocardiogram
Also called EKG or ECG.
A test that records the electrical activity of the heart; it is used to help diagnose certain heart abnormalities.

electromagnetic radiation
Radiation consisting of electric and magnetic waves that travel at the speed of light, such as light, radio waves, gamma rays and x-rays.

electronic detector
The part of a digital imaging system that captures and converts x-rays as they pass through a patient into digital signals which are in turn sent to a computer to produce images.

electronic media
Storage media in PCs and removable/transportable digital media such as magnetic tapes or disks, CDs, pen, flash drives, optical disks, or digital memory cards; or transmission media such as the intranet, dial-up lines, and/or private networks.

electronic medical information
Patient information, including radiological images, lab test results, medications, clinical history, etc., stored on electronic media.

electronic medical record (EMR)
Also called electronic health record.
A computer information system that stores patients’ medical information such as demographics (name, date of birth, address), clinical history, medical images, lab test results, medications, and allergies; it electronically allows healthcare providers to view the information on a computer.

embolic agent
A material used to block off blood flow through a vessel.

embolic stroke
Also called a cerebral embolism
This type of stroke occurs when a blood clot that has formed elsewhere in the body breaks away and travels to a blood vessel in the brain, blocking the flow of oxygen-carrying blood.

embolism
A blood clot (a thickened mass of blood), mass of bacteria or other tissue, air or foreign body that breaks loose, travels through the bloodstream and lodges in either an organ or artery forming a complete or partial blockage in blood flow.

embolization
The movement of a blood clot, piece of tissue, or pocket of air or gas from where it forms through the bloodstream until it lodges in place, cutting off the flow of blood with its oxygen and tissue nutrients. Catheter embolization is the deliberate introduction of foreign ("embolic") material such as gelatin sponge or metal coils to stop bleeding or cut off blood flowing to a tumor or arteriovenous malformation.

embolus, pl. emboli
A plug, composed of a detached blood clot, mass of bacteria or other tissue, air or other foreign body, completely or partially blocking a vessel.

embryo
In humans, the developing organism from conception until approximately the end of the second month; developmental stages from this time to birth are commonly designated as fetal.

emphysema
A common type of chronic obstructive pulmonary disease (COPD). It occurs when the linings of the air sacs within the lungs are damaged and air pockets develop as a result. Once the air becomes trapped, the lungs slowly increase in size and lose their elasticity, which makes breathing difficult because the lungs cannot exhale completely. See the COPD page for additional information.

empyema
An abscess or infection in the space between the lung and the chest wall (pleural space).

encephalitis
An acute inflammation of the brain caused by a viral infection.

encephalography
Radiographic representation of the brain.

encephalopathy
An alteration of normal brain function that can lead to confusion.

encryption
The process of transforming or coding information to make it unreadable to anyone except those possessing special knowledge or the key to decrypt the data.

endocrine gland

  1. A gland that produces and secretes hormones into the blood or lymph nodes, exerting powerful effects on specific tissues throughout the body.
  2. An organ consisting of specialized cells that produces and sends hormones into the bloodstream, affecting various processes throughout the body.

endoluminal
Referring to the inside.

endometrial ablation
A treatment for abnormal vaginal bleeding in which the lining of a woman's uterus (called the endometrium) is destroyed.

endometrial biopsy
A procedure in which a sample of tissue from the lining of the uterus, called the endometrium, is removed and examined for abnormal cells under a microscope.

endometrial cavity
The space within the walls of the endometrium.

endometrium
The mucous membrane that forms the inner layer of the uterine wall; the thickness of the endometrium undergoes marked changes with the menstrual cycle.

endorectal coil
A wire coil that is inserted through a small plastic tube into the rectum as part of a magnetic resonance imaging (MRI) exam to obtain more detailed images of the prostate gland or other internal body structures.

endorectal MRI
A magnetic resonance imaging (MRI) performed from the inside of the rectum.

endoscope
An illuminated optical instrument used to examine inside the body.

endoscopic mucosal resection
A procedure in which an early stage cancer of the esophagus is removed using a thin tube called an endoscope that is inserted into the throat.

endoscopic retrograde cholangiopancreatography (ERCP)
An endoscope, an illuminated optical instrument, is inserted through the mouth and threaded through the esophagus to the small intestine to allow the bile duct, liver, gallbladder, and pancreas to be examined. A contrast material is then injected into the small intestine and x-rays are taken.

endoscopic treatments
Treatment methods that involve the use of an endoscope, an illuminated optical instrument used to examine inside the body.

endoscopy
The use of an illuminated optical instrument to visualize the interior of the body and its organs.

endovaginal
Within the vagina (the genital canal in the female, extending from the uterus to the vulva).

endovaginal ultrasonography
Pelvic ultrasonography using a probe inserted into the vagina.

endovascular surgery
A procedure to repair an aneurysm in the abdominal aorta in which a synthetic tube called a stent graft is attached to the end of a catheter, inserted through an artery in the leg and positioned inside the aneurysm and fastened in place with small hooks.

endovascular therapy
Minimally invasive procedures used to improve blood flow in the brain's arteries and veins. In these treatments, an image-guided catheter is navigated through the body’s blood vessels to the brain to deliver medications or devices that dissolve or remove blood clots and other debris, or to repair damaged blood vessels.

endovenous
Within the vein.

endovenous ablation
A minimally invasive treatment that uses heat to cauterize or burn enlarged veins in the legs, a condition called varicose veins.

enema
A preparation that involves injecting liquid into the intestine through the rectum, or administering drugs or food to help clear the bowel.

enzyme
A protein that regulates chemical changes in other substances.

epididymis
A long, tightly coiled tube that lies behind each testicle. The epididymis collects the sperm made by the testicles.

epididymitis
An inflammation of the epididymis.

epidural analgesia
Injection of a local anesthetic into the epidural space of the spine to prevent or eliminate pelvic pain.

epidural hematoma
May be intracranial (in the skull) or in the spine.

  1. In this type of hematoma, a blood vessel outside the brain, usually in a groove on the inner side of the skull bursts. Because it is usually an artery that is involved, blood begins to rapidly accumulate between the inside of the skull and the strong outer covering of the brain (called dura mater). The pressure of the blood clot strips the dura mater away from its normal firm attachment to the inside of the skull. The blood clot then can press on the brain, causing injury, and if not diagnosed and treated promptly, may be fatal.
  2. In spinal epidural hematoma, the bleeding into the space between the spinal column and the outer lining of the spinal cord may be a result of trauma, bleeding disorders, underlying vascular abnormalities or may occur spontaneously.

erythrocytes
See red blood cells.

esophageal reflux
A condition in which stomach contents (food or acids) move up into the esophagus, the passageway between the stomach and the mouth, and is tasted in the mouth.

esophagectomy
A surgical procedure in which a portion of the diseased esophagus and nearby lymph nodes are removed and the remaining esophagus is reconnected to the stomach using a plastic tube or part of the patient’s gastrointestinal (GI) tract.

esophagitis
Inflammation of the esophagus, the tube-like structure connecting the throat with the stomach.

esophagogastrectomy
A surgical procedure in which a portion of the diseased esophagus nearby lymph nodes and the diseased part of the stomach are removed and the remaining esophagus is reconnected to the stomach using a plastic tube or part of the patient’s gastrointestinal (GI) tract.

esophagoscope
A long, narrow tube with a light and lens that is used for examining the throat and esophagus.

esophagram
Also called a barium swallow.
An x-ray examination that uses a barium sulfate contrast material to assess both the pharynx and esophagus in the upper gastrointestinal tract.

esophagus
The "food tube" which connects the mouth to the stomach.

excisional biopsy
A type of surgical biopsy in which an entire lesion or abnormal group of cells and tissue as well as a surrounding margin of normal-appearing tissue are removed.

exercise cardiac stress test
(also called a cardiac stress test or exercise electrocardiogram)
A test that involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty while heart rate and rhythm, blood pressure and the electrical activity of the heart (using electrocardiography) are monitored to determine if there is adequate blood flow to the heart when the heart is stressed.

external beam therapy
Also called external radiation therapy.
A method whereby highly focused beams of high-energy x-rays are targeted at the tumor site to destroy cancer cells while sparing surrounding normal tissues. See the External Beam Therapy page for additional information.