Glossary Index by Letter

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Interventional Radiology

The clinical subspecialty that uses fluoroscopy, CT, and ultrasound to guide percutaneous (through the skin) procedures such as performing biopsies, draining fluids, inserting catheters, or dilating or stenting narrowed ducts or vessels. Interventional radiologists...

Intestinal Polyps

Small growths in the bowel with the potential for further growth. Intestinal polyps may transform from a benign to a malignant state.


Within the skull. Intracranial Pressure is the pressure within the cranial cavity, influenced by brain mass, the circulatory system, cerebrospinal fluid dynamics, and skull rigidity. Increased intracranial pressure, or rise in normal brain pressure, can be due to a...


Into a muscle. Within or into muscle, such as injection into muscle (IM)


Within the sella turcica. The sella turcica is the bony structure at the base of the skull in which the pituitary gland rests.


Into a tumor (usually performed during surgery). Into a tumor (usually performed during surgery).


Within the uterus. Inside the uterus (the hollow muscular organ in which the impregnated ovum or egg is developed into an infant).


Into a vein. Into or within a vein. Intravenous usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein (IV).

Intravenous Pyelography (IVP)

Radiography of kidneys, ureters, and bladder following injection of contrast medium into a peripheral vein. X-ray study of the kidneys, ureters, and bladder. The x-rays are taken after a dye is injected into a blood vessel. The dye is concentrated in the urine, which...


Into a ventricle. Intraventricular infusion is the delivery of a drug into a fluid-filled cavity within the heart or brain.


Refers to a tumor that invades healthy tissues. The opposite of encapsulated. Also called diffuse or infiltrating. Procedures that violate the body are also called invasive.


Immunoradiometric assay. Immunoradiometric assay.


Treatment by ionizing radiation, such as x-rays, or radioactive sources such as radioactive iodine seeds. The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a...

Irritable Bowel Syndrome

Characterized by abdominal pain and altered bowel function – alternating bouts of constipation and diarrhea. Irritable bowel syndrome is a disorder characterized most commonly by cramping, abdominal pain, bloating, constipation, and diarrhea. IBS causes a great deal...


An acronym of light amplification by stimulated emission of radiation. A surgical tool that creates intense heat and power when focused at close range, destroying cells by vaporizing them.


In radiology, slang for a lateral X-ray. In anatomy, the side of the body or a body part that is farther from the middle or center of the body. Typically, lateral refers to the outer side of the body part, but it is also used to refer to the side of a body part. For...


Lean body mass. The body composition of fluids and muscle tissue. Separate and distinct from fat mass.


Low-density lipoproteins The LDL (Low Density Lipoprotein) is a unit made up of proteins and fats that carry cholesterol in the body. An LDL test measures how much low-density lipoprotein (LDL) you have in your blood. High levels of LDL cholesterol cause a buildup of...


Sluggishness, drowsiness, indifference. A condition marked by drowsiness and an unusual lack of energy and mental alertness. It can be caused by many things, including illness, injury, or drugs.

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