Taber's Medical Dictionary
scan
(skan)
[Ult. fr L. scandere, to read or measure verse]
1. An image obtained from a system that compiles information in a sequence pattern, such as CT scan, ultrasound, or magnetic resonance imaging. SEE: 2. Scintiscan.
anatomy scan
A detailed scan of a fetus, used to determine the presence of congenital anomalies.
bone scan
A nuclear medicine scan that uses short half-life radioactively labeled chemicals to make images of bones and bone diseases, such as occult fractures, osteomyelitis, or tumors. This is esp. useful in delineating osteomyelitis and metastases to the bone.
BONE SCAN Whole skeleton bone scan. Diagnosis for this patient was degenerative joint disease in multiple sites (see arrows indicating increased uptake in the cervical spine, wrist, ankle, and toes). The arrowhead indicates a total joint prosthesis at the knee.
brain scan
Any procedure for imaging the structure and function of the brain.
CAT scan
computed axial tomography scan, a colloquial term for computed tomography (CT) scan.
SEE: computed tomography
coronary artery scan
ABBR: CAS A noninvasive diagnostic computed tomography (CT) scan that may identify patients at risk for atherosclerosis and coronary disease episodes by measuring calcium in the coronary arteries.
DEXA scan
dimercaptosuccinic acid scan
ABBR: DMSA scan A radionuclide scan used to determine the size, shape, and location of the kidneys and the presence of any kidney scarring.
PATIENT CARE
The patient receives an intravenous injection of a radiopharmaceutical DMSA that tends to collect in parts of the kidney that work normally. Two to 4 hr after the injection, the patient lies still under a gamma camera, which creates an image of the kidneys by collecting the radiation given off by the injected tracer. Any nonfunctioning (scarred) portion of a kidney and any part of the kidney that is not receiving adequate blood flow from the renal arteries does not take up the tracer.
gamma scan
Any radiological technique that relies on the detection of gamma particle-emitting radionuclides. Examples of gamma scans include bone scans, gallium scans, and positron emission tomography scans.
HIDA scan
An imaging procedure for evaluating diseases of the liver, gallbladder, and bile ducts. Hydroxy-iminodiacetic acid (HIDA), is injected into the bloodstream. Its excretion through the biliary tract is observed with a scintillation counter in a nuclear medicine laboratory. Normally, HIDA travels from the bile ducts through the cystic duct and into the gallbladder, then out the common bile duct through the sphincter of Oddi into the duodenum. When the flow of bile is obstructed by disease (as by a stone, stricture, or malignancy), the passage of the tracer through the biliary tree is slowed or undetectable.
SEE: cholescintigraphy
Meckel scan
milk scan
A colloquial term for radionuclide reflux imaging.
SEE: radionuclide reflux imaging
multigated acquisition scan
ABBR: MUGA A nuclear medicine scan for measuring the ejection fraction. The MUGA is performed by withdrawing a small amount of blood from the patient; the blood cells are incubated with a radioactive tracer, such as technetium or sestamibi, and then reinfused into the patient. A radioactive detector measures the quantity of blood in the heart at each of multiple stages in systole and diastole. Data obtained from the study are used to calculate the average expulsion of blood during each heartbeat.
SYN: SEE: multigated ventriculogram; SEE: nuclear ventriculogram; SEE: radionuclide ventriculogram
triple rule-out scan
Computed tomography angiography performed on patients who come to the Emergency Department with chest pain of unknown cause. It is used to determine if a patient with chest pain has an acute coronary syndrome, a pulmonary embolism, or an aortic dissection.
ventilation/perfusion scan
ABBR: V/Q scan An imaging procedure used in the diagnosis of pulmonary embolism. The procedure has two parts: the injection of microscopic spheres into the bloodstream to evaluate perfusion of the lung; and the inhalation of xenon gas to assess pulmonary aeration. Certain patterns of mismatching between ventilation and perfusion of the lung are considered to be diagnostic of pulmonary embolism.
