Author/Editor     Beravs, Katarina; White, David; Serša, Igor; Demšar, Franci
Title     Electric current density imaging of bone by MRI
Type     članek
Source     Magn Reson Imaging
Vol. and No.     Letnik 15, št. 8
Publication year     1997
Volume     str. 909-15
Language     eng
Abstract     Current density imaging (CDI) has been shown to be a feasible method to map spatial distribution of electric currents through bone structures and for studying osteoporosis and bone fracture models. For the osteoporosis model, bone sample was moistened in a solution of a sodium salt of ethylendiamintetraacetic acid (EDTA) which causes chemical reaction with hydroxyapatite Ca2+ ions and lowers the mineralisation degree of the solid bone. This enables clear visualisation of conventional magnetic resonance imaging and CDI. Sensitivity of conventional magnetic resonance and CD images of bone was improved by immersing the bone samples into physiological saline containing contrast agent Gd-DTPA prior to imaging. To stimulate effects of bone fracture on electric current conductivity through bone, a transverse cut was made through the bone, and the resulting gap was filled with an insulator. Electric current density images under these conditions have shown that regions of strong conductivity can be distinguished from regions of no conductivity at the site where the insulator restricts electric current. Real bone fracture was imaged as well. To demonstrate influence of electrolyte concentration on electric current spatial distribution, the bone samples were imaged after being immersed in various saline concentrations. The same contrast in current density images was produced with the combinations of higher electrolyte concentrations and lower voltages. Our observations demonstrate the feasibility of the method in mapping current density in bone structures, which could have implications in understanding and monitoring the effects of the electrical stimulation.
Descriptors     FRACTURES
MAGNETIC RESONANCE IMAGING
OSTEOPOROSIS
CHICKENS
EDETIC ACID
ELECTRIC STIMULATION
ELECTRODES
IMAGE ENHANCEMENT
MODELS, STRUCTURAL