Magnetic Resonance Imaging

What is a magnetic field and what is it measured in?

A region of space in which magnetic forces are experienced.

Measured in Teslas

What is a magnetic moment?

A quantity that represents the direction and strength of a magnetic field.

The stronger the magnetic field strength the stronger the magnetic moment.

The direction is how it will align with the magnetic field.

What is Superconducting Magnet?

High resistance increases the temperature of the coil. This is cooled to a low temperature in order the operate. The MRI scanner is cooled with liquid helium.

What are Radiofrequency coils?

To produce an image a radiofrequency pulse is administered to the patient. There are produces via the radiofrequency transmitter coils which are located within the main magnet.

What are Receiver coils?

Surface coils that receive the MRI signal. They are designed specifically for certain areas and need to be places over the area to be imaged and be as close to the patient as possible.

How do protons/neutrons move in the nucleus of an atom?

• protons and neutrons spin in opposite directions in the nucleus

• in atoms with equal number of p/n, the nucleus has no net spin

• when amount of p/n is unequal, the nucleus will have a net spin

What type of atoms are said to be MRI active and why?

Atoms with an odd mass number → because they have a tendency to align their axis of rotation to an applies magnetic field