Points covered: MRI basic Principle T1 and T2 weighed Sequences RF and gradient pulse: Significance in imaging

1. MRI Sequences
Presented By:
Mr. Shishir Badave

2. Introduction
• An MRI sequence is a number of
radiofrequency pulses and gradients that
result in a set of images with a particular
appearance.

6. RF Pulse and Gradients
• RF Pulse: In contrast to the main static
magnetic field, radiofrequency (RF) pulses and
magnetic gradients are only present during
scanning. RF energy (64 MHz-between AM
and FM radio) is exchanged with the patient in
order to create MR images.

7. RF Pulse and Gradients
• The magnetic field of specific strength is
present in the MRI instrument throughout the
Imaging period.
• The RF pulse is produced during the scanning,
The value of which has it’s significance in
producing images

12. T1 weighted sequences
T1 weighted sequences are part of almost all MRI protocols
and are best thought of as the most 'anatomical' of images,
resulting in images that most closely approximate the
appearances of tissues macroscopically, although even this is a
gross simplification.
The dominant signal intensities of different tissues are:
fluid (e.g. urine, CSF): low signal intensity (black)
muscle: intermediate signal intensity (grey)
fat: high signal intensity (white)
brain
grey matter: intermediate signal intensity (grey)
white matter: hyperintense compared to grey matter
(white-ish)

13. T2 weighted sequences
T2 weighted sequences are part of almost all MRI
protocols. Without modification the dominant signal
intensities of different tissues are:
fluid (e.g. urine, CSF): high signal intensity (white)
muscle: intermediate signal intensity (grey)
fat: high signal intensity (white)
brain
grey matter: intermediate signal intensity (grey)
white matter: hypointense compared to grey matter
(dark-ish)

14. Tweaks:
1) Contrast enhanced
(Use of Gadolinium)
2) Fat suppression
(Reduces the bright signal from fat
3) Fluid attenuated
(Reduces the glare)

17. Applications:

18. Basic MRI Sequences