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.
Receivercoil 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.
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.
(BW) Bandwidth is a measure of frequency range, the range between the highest and lowest frequency allowed in the signal. For analog signals, which can be mathematically viewed as a function of time, bandwidth is the width, measured in Hertz of a frequency range in which the signal's Fourier transform is nonzero.