Fundamentals Of MRI Studies: MRI Sequences

OVERVIEW

This page is dedicated to discussing the topic of MRI sequences. This is often a concept that is overcomplicated and difficult for trainees to wrap their heads around. This guide is aimed to try and simplify the topic and give its readers functional knowledge on the topic.

WHAT ARE MRI SEQUENCES?

Very simply put an MRI sequence refers to a particular set of radiofrequence pulses and gradients that produces a set of MRI appearance with a particular appearance. The specific physics behind each MRI series can get confusing, however fundamentally MRI series are utilized because each series will make specific tissue types/anatomical structures/pathological findings look slightly different. In summing up the information gained from each MRI series, those interpreting the images can make a more educated analysis as to what they are seeing.

T1 WEIGHTED SEQUENCES

T1 weighted sequences are a part of most any MRI protocol, and are thought to represent the imaged structures in their most “anatomically accurate” form. There are a few things to keep in mind when thinking about this MRI sequence:

  • Contrast (gadolinium) will cause enhancement: on this series IV contrast will appear bright.
  • Fat suppression: the fat signal present in tissues
  • Appearance of various things:
    • Fluid (urine/CSF): low signal intensity (black)
    • Muscle: intermediate single intensity (grey)
    • Fat: high signal intensity (white)
    • Grey matter: intermediate signal intensity (grey)
    • White matter: hyperintense relative to grey matter (white-ish)

 

T2 WEIGHTED SEQUENCES

 

FLAIR SEQUENCES

 

Page Updated: 08.06.2017