In trace images, the contrast is generated by the direction of the diffusion tensor. This parametric images contains the average of the three eigenvalues (independent of the frame of reference).

Also called transversal. A plane perpendicular (rotated 90°) to the long axis of the human body.

Electrical device operating on the principle of mutual induction to change the magnitude of current and voltage.

(T/R) Also called transceiver coil. An RF coil that acts as a transmitter (T) producing the B1 excitation field and as a receiver (R) of the MRI signal. Such a coil requires a T/R switching circuit to switch between the two modes. A body coil is typically a T/R coil, but smaller volume T/R coils (head/extremities) are often used at high field as a possibility of reducing RF power absorption (SAR).

The portion of the MRI system that produces the RF current and delivers it to the transmitting coil (antenna). The RF signal produced by the transmitter is used to excite the protons in the imaging volume. Phase sensitive detectors (electronic device in which the output is dependent on the instantaneous difference in phase between two input signals) form part of the frequency synthesis pathway.