Question

In any given pulse sequence, when there is a transmitted application of a 90-degree or 180-degree RF pulse, the _____ must be turned on to allow a specific slice to be singled out

A) Gradient Coils
B) Radiofrequency Coils
C) Shim Coils
D) Phased-Array Coils

Answer 1

The gradient coils must be turned on during pulse sequences in MRI to isolate a specific slice for imaging by creating a variable magnetic field that targets specific regions.

Step-by-step explanation:

In any given pulse sequence, when there is a transmitted application of a 90-degree or 180-degree RF pulse, the gradient coils must be turned on to allow a specific slice to be singled out. The purpose of the gradient coils is to produce a variable magnetic field across different axes, which enables the Magnetic Resonance Imaging (MRI) system to target a specific area within the three-dimensional space of the subject's body. This change in the magnetic field makes the resonant frequency of the nuclei vary with position, allowing the imaging system to gather precise spatial information and to build up a cross-sectional image of the body.