MRI Terminology

3. Preferred (SI) unit of magnetic flux density or magnetic field intensity
4. Spin-lattice, or longitudinal, relaxation time; characteristic time constant for spins to tend to align themselves with the external magnetic field
6. Atmospheric gases such as nitrogen and helium that have been cooled sufficiently to condense into a liquid
7. Spin-spin, or transverse, relaxation time; characteristic time constant for loss of phase coherence among spins oriented at an angle to the main magnetic field owing to interactions between the spins
8. MRI contrast agent
10. Field Stray magnetic field that exists outside the imager
11. MRI technique used to minimize motion artifacts, in which conventional electrocardiography or photopulse sensing is used to trigger the acquisition of image data. Times the data acquisition with physiologic motion

1. Ability of an imaging process to distinguish adjacent soft tissues from one another. This is the principal advantage of MRI
2. Unit of magnetic flux density in the older CGS system
5. Signal-to-noise ratio - enhancing technique in which the same MRI signal is repeatedly acquired two or more times and then is combined and averaged
9. Single or multiple loops of wire designed to produce a magnetic field from current flowing through the wire or to detect a changing magnetic field by voltage induced in the wire
10. Field of View; Area (usually expressed in centimeters) of the anatomy that is being imaged; a function of acquisition matrix times pixel size