Current density imaging
Encyclopedia
Current density imaging is an extension of magnetic resonance imaging
(MRI), developed at the University of Toronto
.
It employs two techniques for spatially mapping electrical current pathways through tissue
:
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI), developed at the University of Toronto
University of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
.
It employs two techniques for spatially mapping electrical current pathways through tissue
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
:
- LF-CDI, low-frequency CDI, the original implementation developed at the University of Toronto. In this technique, low frequency (LF) electrical currents are injected into the tissue. These currents generate magnetic fieldMagnetic fieldA magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
s, which are then measured using MRI techniques. The current pathways are then computed and spatially mapped. - RF-CDI, radio frequency CDI, a rotating frame of reference version of LF-CDI. This allows measurement of a single component of current density, without requiring subject rotation. The high frequency current that is injected into tissue also does not cause the muscle twitching often encountered using LF-CDI, allowing in-vivo measurements on human subjects.