The portion of the MRI equipment that detects and amplifies the RF signals picked up by the receiver coil. Includes a preamplifier, MR signal amplifier, and demodulator. Phase sensitive detectors (electronic device in which the output is dependent on the instantaneous difference in phase between two input signals) are used to down-convert the MR signal to audio-frequencies prior to digitization.

See also MRI Equipment.

A coil, or antenna, positioned within the imaging volume and connected to the receiver circuitry that is used to detect or receive the MR signal from the patient as the disturbed spins relax back into their equilibrium distribution. Also called receive-only coil.
Special-purpose coils are designed to optimize the SNR from a given region of the body. State-of-the-art coil systems include the use of four or more coils with four separate receivers. This method is often referred to as a phased array system. Receiver coil types include also solenoid, planar, volume and quadrature coils. The quality of the MR images depends on the SNR of the acquired signal from the patient. SNR is of the utmost importance in obtaining clear images of the interior of the human body.

Time after exciting RF pulse during which FID is not detectable due to saturation of receiver electronics.

Quick Overview

A receiver turn on artifact (not a true MR signal) appears similarly like a FID signal artifact, except that they extend into the signal-free region, while the FID (a real MR signal) is confined to the projection of the sample along the readout axis.

FID artifacts cannot occur on gradient echo images, but receiver turn on is still possible on gradient echoes.

See also FID Signal Artifact.

The mathematical process by which the displayed image is produced from the raw k-space data obtained from the receiver circuitry, typically utilizing Fourier transformation and selective filtering.