Oct 14, 2020 · Free induction decay (FID) refers to a short-lived sinusoidal electromagnetic signal which appears immediately following the 90° pulse. It is induced in the receiver coil by the rotating component of the magnetization vector in the x-y plane …

Sep 14, 2024 · Some artifacts affect the quality of the MRI exam, while others do not affect the diagnostic quality but may be confused with pathology. When encountering an unfamiliar artifact, it is useful to systematically examine general features of …

Apr 2, 2020 · A picture of the signal or free induction decay (FID) is shown on the right, occurring immediately after a 90 o RF excitation pulse in a liquid phantom. Discussion. Following the excitation pulse, there is an immediate exponential loss of …

Jan 17, 2025 · Steady-state free precession MRI (SSFP) is a type of gradient echo MRI pulse sequence in which a steady, residual transverse magnetization (M xy) is maintained between successive cycles. The sequence is noted for its superiority in dynamic/cine assessment of cardiac function.

Nov 29, 2021 · An MRI pulse sequence is a programmed set of changing magnetic gradients. Each sequence will have a number of parameters, and multiple sequences grouped together into an MRI protocol.

Apr 2, 2020 · The gradient echo is generated by the frequency-encode gradient, except that it is used twice in succession, and in opposite directions: it is used in reverse at first to enforce transverse dephasing of spinning protons and then right after, it is used as a readout gradient (like in spin-echo MRI) to re-align the dephased protons and hence ...

Apr 2, 2020 · In MRI, spatial resolution is defined by the size of the imaging voxels. Since voxels are three-dimensional rectangular solids, the resolution is frequently different in the three different directions.

Feb 18, 2024 · Fourier transform is integral to all modern imaging, and is particularly important in MRI. The signal received at the detector (receiver coils in MRI, piezoelectric disc in ultrasound and detector array in CT) is a complex periodic signal made of a large number of constituent frequencies (i.e., bandwidth).

Aug 8, 2023 · Saturation recovery (SR) sequences are rarely used for imaging now. Their primary use at this time is as a technique to measure T1 times more quickly than an inversion recovery pulse sequence. Saturation recovery sequences consist of multiple 9...

Sep 4, 2022 · An MRI sequence is a number of radiofrequency pulses and gradients that result in a set of images with a particular appearance. This article presents a simplified approach to recognizing common MRI sequences, but does not concern …