Open AccessThe biophysical basis of tissue contrast in extracranial MR imaging
Author(s) -
David Mitchell,
D L Burk,
Simon Vinitski,
Rifkin
Publication year - 1987
Publication title -
american journal of roentgenology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 196
eISSN - 1546-3141
pISSN - 0361-803X
DOI - 10.2214/ajr.149.4.831
Subject(s) - medicine , contrast (vision) , relaxation (psychology) , macromolecule , nuclear magnetic resonance , biomedical engineering , biochemistry , chemistry , artificial intelligence , computer science , physics
So that radiologists can understand better the differences between tissues that determine MR image contrast, the biophysical basis of proton-MR tissue contrast is reviewed. Differences in the molecular sizes of water, fat, and protein macromolecules affect the rate of molecular motion, which in turn influences relaxation times. Differences in the physical state of water within tissues determine the extent to which the motion of water is restricted by binding to hydrophilic macromolecules (e.g., protein), which in turn causes variable amounts of T1 and T2 shortening. Understanding these concepts and knowing the location in the body of free water, cellular tissues, fat, collagen, bone, and tissue iron improve the radiologist's ability to extract useful information from MR images.