MR Glossary Quiz

_____ is a term describing the containment of the static magnetic field through the use of secondary coils attached around the MRI scanner

Active shielding

The _____ is an integrated part of the magnet design that acts as its own transceiver coil, with large FOV capabilities, but lacking the high SNR of localized coils

Body coil

In diffusion weighted imaging, the degree of diffusion sensitization is controlled by the:

B value

The _____ is defined as the main magnetic field of an MR system

B0

The ____ is the alternating magnetic field generated by the RF in a transceiver coil

B1

To obtain clear images of the beating heart, a technologist uses the EKG signal to time the scan to each heartbeat. This technique to reduce motion artifacts is known as:

Cardiac triggering

An MRI of the orbits shows a dark line on one side of the optic nerve and a bright line on the other. This is a classic example of:

Chemical shift artifact

Describing image display, ______ function scrolls through the entire sequences images, giving the appearance of CSF flowing or cardiac movement, from the cycle of the images acquired

Cine

Can be defined as the signal strength differences between two adjacent tissue types

Contrast

To visualize the renal arteries, a technologist injects a gadolinium agent and acquires a rapid T1 weighted scan. This MRA technique is known as:

CE MRA

A technologist notices that slices in the middle of an acquisition have lower signal than slices at the ends. This is likely due to, where RF pulses for adjacent slices interfere with each other

Cross talk artifact

______ is a term used to describe the adjustment of the current within the shim coils on a per patient or per sequence basis

Active shimming

Occurs after initial RF application, causing phase differences to appear between precessing spins, resulting in decay of transverse magnetization

Dephasing

______ is an effect resulting in a slightly weakened magnetic field when a substance is introduced into it. This material is considered to have a negative magnetic susceptibility

Diamagnetism

An _______ is the MR signal generated by an RF or a gradient pulse

Echo

______ is simply defined as the distance between echoes

Echo spacing

The time between the excitation pulse of a sequence and the resulting echo used as the MR signal is known as:

Echo time

A technique used to suppress fluids, utilizing a long echo time coupled with a long inversion time is known as:

FLAIR

Materials, such as iron, contain unpaired electrons, each with a small magnetic field of its own, that align readily with each other in response to an external magnetic field

Ferromagnetic

The mathematical process of converting raw data into an image suitable for display is known as

Fourier transform