Glossary of Terms


Computed Tomography (CT)
Contrast Material
Coronary Angiography
Doppler Ultrasonography
Interventional Radiology
Intravenous Pyelogram (IVP)
Magnetic Resonance Angiography (MRA)
Magnetic Resonance Cholangiopancreatography (MRCP)
Magnetic Resonance Imaging (MRI)
Needle Biopsy
Nuclear Medicine
Ovarian Vein Embolization
Pyelogram (IV Urogram/IVP)
Stent Placement
Uterine Fibroid Embolization


ANGIOGRAPHY: A radiographic technique in which a radiopaque (shows up on X-ray) contrast material is injected into a blood vessel for the purpose of identifying its anatomy on an X-ray. This technique is used to image arteries in the brain, heart, kidneys, gastrointestinal tract, aorta, neck (carotids), chest, limbs, and pulmonary circuit.

ANGIOPLASTY: An interventional radiology procedure in which the radiologist inserts a miniature balloon attached to a thin tube (catheter) into a blood vessel through a tiny nick in the skin. The catheter is threaded under X-ray guidance to the site of the blocked artery. The balloon is inflated to open the artery.

ARTERIOGRAM: An angiogram of an artery.

ARTHROGRAM: The visualization of a joint by X-ray after the injection of dye into the joint.

ASPIRATE/ASPIRATION: Withdrawal of a fluid from the body by suction, usually through a needle or syringe.

BIOPSY: The removal and examination of a piece of tissue taken from the body for diagnostic purposes.

COMPUTED TOMOGRAPHY: Also known as CT scan or CAT scan (Computer Assisted Tomography). A special radiographic technique that uses a computer to assimilate multiple X-ray images into a 2-dimensional cross-sectional image. This can reveal many soft tissue structures not shown by conventional radiography. Scans may also be dynamic, in which movement of a dye is tracked. Cuts may be 1 mm apart to several mm (10-15) apart. Special dye materials may be injected into the patient's vein prior to the scan to help differentiate abnormal tissue and vasculature. The machine rotates about 180° around the patient's body, sending out a pencil-thin X-ray beam. Crystals positioned at the opposite points of the beam pick up and record the absorption rates of the varying thicknesses of tissue and bone. These data are then relayed to a computer that turns the information into a picture on a screen. Using the same dosage of radiation as that of the conventional X-ray machine, an entire slice of the body is made visible with about 100 times more clarity. The scanner was invented in 1972 by the British electronics engineer Sir Godfrey Hounsfield, and was in general use by 1979.

CONTRAST MATERIAL: (Also referred to as contrast agent or contrast medium.) Any internally administered substance that has a different opacity from soft tissue on radiography, computed tomography, or MRI. Includes barium, used to make opaque parts of the gastrointestinal tract; water-soluble iodinated compounds, used to make opaque blood vessels or the genitourinary tract; may refer to air occurring naturally or introduced into the body; also, paramagnetic substances used in magnetic resonance imaging. Used during certain X-ray exams, CT exams, and MRI exams to provide visual contrast in the pictures of different organs and tissues. Can be given orally or intravenously. "Dye" usually refers to the contrast media given intravenously. In MR studies, the contrast is called gadolinium. The use of contrast may rarely result in some adverse effects. It increases the accuracy of the scan.

CORONARY ANGIOGRAPHY: A study of the blood vessels which supply the muscle of the heart (coronary arteries). By threading a long, narrow, flexible catheter through an accessible blood vessel (usually in the groin or arm), the individual coronary arteries are injected with a small quantity of X-ray dye, which helps radiologists look for blockages (stenoses). Cardiac catheterization refers to the technique of performing coronary angiography, whereby catheters are threaded into the heart and coronary arteries.

DOPPLER ULTRASONOGRAPHY: An application of diagnostic ultrasound used to detect moving blood cells or other moving structures and measure their direction and speed of movement. The Doppler effect is used to evaluate movement by measuring changes in frequency of the echoes reflected from moving structures. In many instances, Doppler ultrasound has replaced x-ray methods such as angiography, as a method to evaluate blood vessels and blood flow. Doppler ultrasound permits real-time viewing of blood flow that cannot be obtained by other methods. Doppler ultrasound has proven to be a boon in all areas of ultrasound, aiding in the evaluation of the major arteries and veins of the body, the heart, and in obstetrics for fetal monitoring.

ECHOCARDIOGRAPHY: A painless study using ultrasound waves to visualize structural and functional abnormalities of the heart.

FLUOROSCOPY: A real-time X-ray procedure that makes it possible to see internal organs in motion.

INTERVENTIONAL RADIOLOGY: A subspecialty of radiology that uses image-guided, minimally invasive techniques for the diagnosis and/or treatment of a variety of medical conditions, and often represents a viable alternative to surgery. The interventional radiologist uses miniaturized tools, while watching the progress of the procedure using moving X-rays or other imaging techniques. The procedures are performed in an interventional suite, generally on an outpatient basis. General anesthesia is usually unnecessary. Examples of interventional procedures include angiography, angioplasty, chemoembolization, fallopian tube recanalization, inferior vena cava (IVC) filters, ovarian vein embolization, percutaneous nephrostomy, stent placement, thrombolytic therapy, TIPS (transjugular intrahepatic portosystemic shunt), uterine fibroid embolization, varicocele embolization, and vascular embolization.

INTRAVENOUS PYELOGRAM/IVP: A special diagnostic test that follows the time course of excretion of a radiopaque contrast dye through the kidneys, ureters, and bladder after it is injected into a vein.

MAGNETIC RESONANCE ANGIOGRAPHY/MRA: A method of angiography utilizing the magnetic properties of tissues and body fluids rather than X-rays to create images.

MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY: An examination of the bile ducts and pancreas using magnetic resonance imaging.

MAGNETIC RESONANCE IMAGING/MRI: A special imaging technique used to image internal structures of the body, particularly the soft tissues. An MRI image is often superior to a normal X-ray image. It uses a strong magnet to create images of tissue based on the number and type of hydrogen atoms within the tissue. Images are very clear and are particularly good for soft tissue, brain and spinal cord, joints, and abdomen. These scans may be used for detecting some cancers or for following their progress.

MAMMOGRAPHY: Imaging examination of the breast by means of x-rays, used for screening and diagnosis of breast disease. Ultrasound and magnetic resonance may also be used to image the breast.

MYELOGRAM: An X-ray of the spinal cord after the injection of a radiopaque substance into the subarachnoid space.

NEEDLE BIOPSY: Diagnostic test for breast or other cancers that is an alternative to surgical biopsy. Involves the removal of tissue or suspension of cells through a small needle for diagnostic examination.

NEURORADIOLOGY: The branch of radiology which offers comprehensive diagnostic imaging of the brain, the spine and spinal cord, and the head and neck region, using radiography and fluoroscopy, computed tomography (CT), and magnetic resonance imaging (MRI). State-of-the-art imaging techniques include echo planar techniques, perfusion/diffusion imaging, and PET scan. Noninvasive MR and CT angiography and other three-dimensional imaging techniques are available. Interventional neuroradiologic diagnostic and therapeutic procedures are available, including percutaneous biopsy of head and neck tumors, intra-arterial chemotherapy, and preoperative embolization of tumors and vascular malformations of the head and neck.

NONINVASIVE: Denoting a procedure that does not require insertion of an instrument or device through the skin or a body orifice for diagnosis or treatment.

NUCLEAR MEDICINE: The branch of medicine pertaining to the diagnostic, therapeutic, and investigative use of radioactive chemical elements. Dozens of different examinations are performed in the Nuclear Medicine Department. Minute traces of radioactive material, attached to a variety of molecules, are administered to the patient. The type of radioactive tracer and the type of molecule vary, depending upon which part of the body is to be examined. Scans are obtained with a gamma camera, which measures protons from the decaying radioactive tracers.

PYELOGRAM/IV UROGRAM/IVP: An X-ray of the pelvis, showing the kidney and associated structures, after injection of a radiopaque dye.

RADIOGRAPHY: The making of film records (radiographs) of internal structures of the body by passage of X-rays or gamma rays through the body to act on specially sensitized film.

RADIOLOGY: Medical imaging techniques, employing advanced computers and other complex equipment, that allow doctors to see inside a patient's body. Although the word "radiology" implies radiation, not all of the techniques actually use radiation. And although radiology is most commonly used for diagnosis, it is sometimes used therapeutically.

RADIOPAQUE: Anything that does not allow the penetration of X-rays.

SCAN: Term used to describe the computerized images (pictures) generated by CT, MRI, ultrasound, and nuclear medicine studies. These might be referred to as a "CT scan," "MR scan," "thyroid scan," "bone scan," etc.

SCINTIGRAPHY: A nuclear medicine procedure consisting of the administration of a radionuclide with an affinity for the organ or tissue of interest, followed by recording the distribution of the radioactivity with a stationary or scanning external scintillation camera.

SONOGRAPHY: The location, measurement, or delineation of deep structures by measuring the reflection or transmission of high-frequency or ultrasonic waves. Computer calculation of the distance to the sound reflecting or absorbing surface plus the known orientation of the sound beam gives a two- or three-dimensional image. Synonym: ultrasound.

SPECT: An acronym for single photon emission computed tomography. A nuclear medicine procedure in which the gamma camera rotates around the patient and takes pictures from many angles, which a computer then uses to form a tomographic (cross-sectional) image. The calculation process is similar to that in X-ray computed tomography (CT) and in positron emission tomography (PET).

SPECTROSCOPY: The science of measuring the emission and absorption of different wavelengths (spectra) of visible and non-visible light. This can be done via a spectroscope, which consists of a slit, prism, collimator lens, object lens, and a grating. Hydrogen spectra from living tissue can be obtained using MR spectroscopy.

STENT PLACEMENT: An interventional radiology procedure in which a stent, a tiny metallic tubular mesh, is placed in an artery, acting like scaffolding to keep the artery open.

STEREOTACTIC: The technique of viewing objects from two slightly different angles to give a perception of depth.

ULTRASOUND: A type of imaging technique which uses high-frequency sound waves to make pictures of the body organs. Since no ionizing radiation (X-rays) are used, it is ideal for looking at pregnant women and their fetuses. It is also used for the neck, abdomen, pelvis, and soft tissues, including blood vessels in the arms and legs.

UROGRAPHY: Radiography of any part (kidneys, ureters, or bladder) of the urinary tract.

UTERINE FIBROID EMBOLIZATION: A safe, effective non-surgical treatment for women with symptomatic uterine fibroid tumors. In this procedure, the interventional radiologist guides a small catheter into the uterine arteries and injects a stream of tiny particles that decrease blood flow to the fibroid.

VASOGRAPHY: Radiography of the secretory duct of the testicle (vas deferens), to determine patency (the state of being freely open), by injecting contrast medium into its opening either through the urethra or by incision into the vas deferens.

VENOGRAPHY: An angiogram of a vein.

VERTEBROPLASTY: A procedure used to help people with painful vertebral body fractures. Medical cement is injected into the fractured vertebral body. When the cement hardens, it permanently stabilizes the fracture, thereby relieving back pain.

X-RAY: A type of irradiation used for imaging purposes that uses energy beams of very short wavelengths (0.1 to 1000 angstroms) that can penetrate most substances except heavy metals. This is the most common form of imaging technique used in clinical practice everywhere in the world, with the image captured on photographic film.