MRI and Magnetism Concepts

Front

The anatomy of interest must be positioned at the isocenter to minimize image distortion, as the isocenter corresponds to the center of the magnet bore.

Back

Positioning of the body area in MRI scanning.

Front

Shimming optimizes the homogeneity of an MRI magnet. Passive shimming uses metal plates to offset harmonics, while dynamic shimming adjusts for individual patients using gradient windings.

Back

This is meant by shimming in MRI.

Front

Ferromagnetic materials retain magnetism outside an external magnetic field.

Back

Characteristics of ferromagnetic materials.

Front

Open MRI magnets reduce claustrophobia and accommodate larger patients.

Back

Benefits of open MRI magnets for patients.

Front

Capable of high current with no resistivity losses, maintaining field strength.

Back

Superconducting magnet properties.

Front

The gradient subsystem creates slopes along the main magnetic field.

Back

Used to select slice position, alter slice thickness, and locate returning signal by imposing changes in phase and frequency.

Front

Reason for loud noise in an MRI scan.

Back

Caused by the gradient coil's rapid polarity changes, resulting in vibration and sound waves.

Front

Definition of "filling factor" in an RF receive coil.

Back

Describes how much of the sensitive volume of a coil is filled with the patient’s body tissue.

Front

Zone 01

Back

Zone 01 is a publicly accessible zone. Anyone is permitted to enter.

Front

Zone 03

Back

Zone 03 is only accessible to safety-screened patients and safety-trained personnel. It should be guarded by a locked door.