| hot spleen | <radiology> Decreased liver uptake, liver disease (e.g., cirrhosis), shunting of portal venous blood, increased splenic uptake, haematopoietic disease, septicaemia, rheumatoid disorders, immunostimulation (tumour, Aldomet, IL-2) see: liver-spleen scan (12 Dec 1998) |
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| hot thyroid nodule | <radiology> Almost always hyperfunctioning adenoma, vast majority benign, up to 50% are autonomous see also: thyroid carcinoma, cold thyroid nodule (12 Dec 1998) |
| adrenal imaging | <radiology> Cortex, I-131 iodo-cholesterol, not widely used due to high rad dose and 4-15 day delayed imaging, medulla, search for pheo, MIBG (I-131 meta-iodobenzylguanidine) (12 Dec 1998) |
| adrenal medullary imaging | <investigation, radiology> A nuclear scan that images the adrenal glands after a radioactive tracer is injected into the bloodstream. This test is useful in detecting a pheochromocytoma, particularly if it not within the adrenal gland. (27 Sep 1997) |
| age spot | <dermatology> A skin disorder seen with aging (or sun exposure) where there are flat patches of increased pigmentation on the skin. They are nonserious, benign and generally more important cosmetically. The most commonly appear on sun exposed areas such as the forehead and the back of the hands. Avoidance of the sun and the use of a sunscreen (SPF of 15) can reduce the incidence of these lesions. Creams and lotions are available which bleach the skin. Cryotherapy can be used in some cases. (27 Sep 1997) |
| backscattered electron imaging | <microscopy> The production of backscattered electrons from a sample varies directly with the specimen's average atomic number, higher atomic number elements produce more backscattered electrons than lower atomic number ones. Detection of Backscattered Electrons is achieved by using a donut shaped solid state saemiconductor device mounted on the bottom of the objective lens. When Backscattered Electrons strike the detector electron-hole pairs are created which are then counted. This quantity is translated into a pixel intensity and displayed on the CRT, forming the image. By splitting the detector into halves (or quadrants) differences in the signal level on the individual detector segments provide surface topography information. (05 Aug 1998) |
| blind spot | The negative scotoma in the visual field, corresponding to the optic disk. Synonym: blind spot. (05 Mar 2000) |
| blood pool imaging | Nuclear medicine study using a radionuclide that is confined to the vascular compartment. (05 Mar 2000) |
| blue spot | A bluish stain on the skin caused by the bites of fleas or lice, especially pediculosis pubis. Synonym: blue spot, tache bleuatre. (05 Mar 2000) |
| bone: gallium imaging | <radiology> Increased activity in: active osteomyelitis (90% sensitivity: better than Tc-99m MDP), sarcoma, cellulitis, septic arthritis, rheumatoid arthritis, Paget disease, metastases (65% sensitivity: than for bone agents) see: gallium: indications (12 Dec 1998) |
| bright field imaging | <microscopy> An imaging mode in a transmission electron microscopy that uses only unscattered Electrons to form the image. Contrast in such an image is due entirely to mass-thickness variations in amorphous samples, and may include diffraction contrast in crystalline samples. (05 Aug 1998) |
| cafe-au-lait spot | <dermatology> A pigmented cutaneous lesion, that can range from light to dark brown, and is due to an excess of melanosomes in the malpighian cells, rather than to an excess of melanocytes. Caf |
| cardiac blood pool imaging | This noninvasive test uses radioactive tracers to delineate the hearts chambers and major vessels. It may be used to detect a heart attack, heart muscle function and coronary artery disease. The patient receives a radioactive tracer by injection (into a vein) and then the heart is imaged using a gamma camera. The heart is imaged before and after exercise. This test may be used to detect and evaluate atrial septal defect, dilated cardiomyopathy, congestive heart failure, cardiomyopathy, Lyme disease (secondary), mitral stenosis and superior vena cava syndrome. (27 Sep 1997) |
| radionuclide imaging | Process whereby a radionuclide is injected or measured (through tissue) from an external source, and a display is obtained from any one of several rectilinear scanner or gamma camera systems. The image obtained from a moving detector is called a scan, while the image obtained from a stationary camera device is called a scintiphotograph. (12 Dec 1998) |
| Magnetic Resonance Imaging | A special imaging technique used to image internal stuctures of the body, particularly the soft tissues. An MRI image is often superior to a normal X-ray image. It uses the influence of a large magnet to polarize hydrogen atoms in the tissues and then monitors the summation of the spinning energies within living cells. 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. Acronym: MRI (11 Nov 1997) |