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• MRI Terms

- E -

• ECHO PLANAR IMAGING (EPI)

The utilization of rapid gradient reversal pulses of the readout gradient resulting in a series of gradient echo signals to reduce fast dephasing or signal loss.



• ECHO TIME

See TE.



• ECHO TRAIN

A series of 180� RF rephasing pulses and their corresponding echoes for a Fast Spin Echo (FSE) pulse sequence.



• EDDY CURRENT

An induced spurious electrical current produced by time-varying magnetic fields. Eddy currents can cause artifacts in images and may seriously degrade overall magnet performance.



• ELECTROMAGNET

A type of magnet that utilizes coils of wire, typically wound on an iron core, so that as current flows through the coil it becomes magnetized. See also Resistive Magnet, Superconducting Magnet.



• ELECTRON SPIN RESONANCE (ESR)

The response of electrons to electromagnetic radiation and magnetic fields at discrete frequencies. EPI - echo planar imaging. See also Echo Planar Imaging.



• EQUILIBRIUM

A state of balance that exists between two opposing forces or divergent forms of influence.



• ETL

Echo Train Length



• EXCITATION

Delivering (inducing, transferring) energy into the "spinning" nuclei via radio-frequency pulse(s), which puts the nuclei into a higher energy state. By producing a net transverse magnetization an MRI system can observe a response from the excited system.