subtraction

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subtraction

 [sub-trak´shun]
the photographic or electronic removal of overlying structures from radiologic images.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

sub·trac·tion

(sŭb-trak'shŭn),
A technique used to enhance detectability of opacified anatomic structures on radiographic or scintigraphic images; a negative of an image made before introduction of contrast medium or radionuclide is photographically or electronically removed from a later image; commonly used in cerebral angiography.
See also: digital subtraction angiography, mask.
Farlex Partner Medical Dictionary © Farlex 2012

sub·trac·tion

(sŭb-trak'shŭn)
A technique used to enhance detectability of opacified anatomic structures on radiographic or scintigraphic images; a negative of an image made before introduction of contrast medium or radionuclide is photographically or electronically removed from a later image; commonly used in cerebral angiography.
See also: digital subtraction angiography, mask
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

subtraction

(sŭb-trak′shŏn)
Removal of undesired overlying structures from a radiographical image by superimposing an image taken before the addition of contrast material with one taken after.
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
Only the simplest subtraction and basic addition have been used.
6003 - 2987 Step 1: 9999 - 2987 = 7012 Step 2: 7012 + 6003 = 13 015 Step 3: 13 015 - 10 000 = 3015 Step 4: 3015 + 1 = 3016 Finally check, as in all subtraction problems, that the answer plus the subtrahend yields the minuend.
The renormalization with multiple subtractions handles this problem in a different way since the NN potential is not modified in favour of changing Green's function instead.
Detailed expressions for the integral equations in the recursive calculation with partial wave basis are given in [32] for the case of N2LO interactions with four subtractions.
Small subtractions were verified faster (660 ms) than large subtractions (765 ms) and incorrect problems were solved slower (762 ms) than correct ones (663 ms).
The main effect of Problem size (F(1, 39) = 43.1, p <.001, [[eta].sub.p.sup.2] = .53) was also significant, showing that small subtractions were verified more accurately (97% hits) than large subtractions (89% hits).
Another disadvantage is this technique is not reasonable for subtraction algorithm.
Instead of using a single uniform partition (direct lookup table approach) [2], the technique can be realized by segregating the ROM into various sizes of interval mapping with the domain function of addition and subtraction algorithms.
We record the subtraction with the regrouping on the chalkboard.
Addition and subtraction were not just manipulations of numbers.
Besides ostensibly resulting in point subtractions, completing a FR 10 on Button B could also initiate an interval free from point subtractions (provocation-free intervals).
Subject S-585 emitted extremely high rates of aggressive responding, even though the low provocation condition was in effect which resulted in only 2-5 point subtractions per session.