MRI Physics and Instrumentation

Flashcards covering key concepts related to MRI physics, instrumentation, and magnetic properties of materials.

MRI Machine Diagram

A cross-section diagram showing the inner workings of the MRI machine, including different parts and components.

MRI Vendors

Examples include Philips, Toshiba, Siemens, and GE. Different vendors offer different software versions that are constantly evolving.

Software Evolution in MRI

MRI software is constantly changing and evolving, with different facilities potentially having different versions, even from the same vendor. Terminology can vary across vendors.

Hardware in MRI

Includes a magnet of 40 to 50 centimeters (older machines) or 60 to 70 centimeters (newer machines), with some having an 80 centimeter bore.

Short Bore MRI Machines

Newer MRI machines that are shorter in length compared to older, longer MRI machines with 40-50 cm openings.

Shim System

A system within the MRI magnet used for homogeneity of the magnetic field.

RF Pulses

Radio frequency pulses used as the transmission system to obtain signals in MRI.

Magnetic Field Gradient System

A system in MRI that has linear slopes.

MRI Coils

Used to send and receive signals to image a specific body part; a key difference from CT scans.

Computer Subsystem in MRI

Converts signals into images.

Magnetism

The fundamental property of matter where all substances interact with an applied magnetic field to varying degrees.

Magnetic Susceptibility

Property describing how materials behave in the presence of an external magnetic field.

Atomic Magnetic Dipole

Also known as a 'little magnetic moment'. The degree of magnetism exhibited by a substance is related to these dipoles, generated by the movement of electrons.

Electromagnetic Induction

Whenever a charged particle like an electron exhibits motion, a corresponding magnetic field is induced around it.

Diamagnetism

Materials with paired electrons that show no magnetic moment without an external magnetic field and are slightly repelled by it when a field is applied. Examples: lead, copper.

Paramagnetism

Materials with unpaired electrons that have a small magnetic moment. They align in the direction of an external magnetic field, causing a local increase.