Physics Just the Basics Series #01 - The MRI Signal-Physics Just the Basics

Video Transcription

Video Summary

The webinar introduced the SCMR pilot series “MRI Physics, Just the Basics,” aimed at clinicians and non-physicists. Patricia Bantini opened the session by explaining the format, chat/Q&A features, and the plan for a recorded lecture followed by live questions. She then introduced Dr. Anthony Alatras, who presented the first talk on how MRI signal is generated and how images are formed.<br /><br />Dr. Alatras explained core concepts such as magnitude, frequency, and phase using simple vector analogies. He described how hydrogen protons in water act as tiny magnetic dipoles, how they align in the scanner’s main magnetic field (B0), and how an RF pulse (B1) excites them at the Larmor frequency to create the free induction decay signal. He then showed how gradients along the X, Y, and Z axes are used for slice selection, frequency encoding, and phase encoding, allowing spatial localization of signal and image reconstruction through the Fourier transform.<br /><br />The session ended with a live Q&A covering 3D imaging, resolution, k-space, voxels, and recommended reading. Upcoming webinars will address relaxation and echoes.

Keywords

MRI physics

signal generation

image formation

Larmor frequency

magnetic resonance

gradient encoding

Fourier transform

k-space