Fast Imaging Pulse Sequences (Under Construction)#

Modern MRI scanning relies heavily fast imaging pulse sequences, primarily echo-planar imaging (EPI) and Fast/Turbo Spin-echo (FSE/TSE) methods. These allow for multiple k-space lines to be acquired within a single TR.

Learning Goals#

  1. Describe how images are formed

    • Describe how EPI works

    • Describe how data is acquired in FSE/TSE sequences

  2. Understand the most popular pulse sequences and their acronyms

    • Describe how EPI works

    • Describe how FSE/TSE sequences work

  3. Manipulate MRI sequence parameters to improve performance

    • Understand how and when to accelerate with EPI

    • Understand how and when to accelerate with FSE/TSE

  4. Identify artifacts and how to mitigate them

    • Identify EPI artifacts including distortion and T2*

    • Identify FSE/TSE artifacts include T2 blurring

Echo-planar Imaging (EPI)#

These pulse sequences readout multiple k-space lines in a row for faster imaging.

Fast/Turbo Spin-echo (FSE/TSE)#

These pulse sequences use multiple spin-echo refocusing pulses after a single exictation pulse. This enables multiple k-space lines to be acquired during the multiple spin-echoes that are formed. This technique was originally called Rapid Acquisition with Relaxation Enhancement (RARE), and is known on various MRI scanners as fast spin-echo (FSE, GE Healthcare), turbo spin-echo (TSE, Siemens Healthineers), or turbo field-echo (TFE, Philips Healthcare).