Minimum-Time Variable-Rate Selective Excitation (VERSE)

Brian Hargreaves and Chuck Cunningham

Introduction

This page provides the C code (including a MEX interface for Matlab) for minimum-time VERSE RF/gradient design. For reference, see our article, Variable-Rate Selective excitation for rapid MRI sequences Magnetic Resonance in Medicine 52(3): 590-597 (Sept 2004).

The purpose of the code is to take a constant-gradient excitation and transform it to a minimum-time B1 and gradient pair that has the identical spatial excitation profile. The minimum-time design is subject to given gradient amplitude and slew-rate limits and RF amplitude limits. An example is shown below. A "standard" RF pulse and constant gradient waveform are shown at left. The minimum-time VERSE equivalent pair (subject to hardware limits) are shown at right.


(Click on image to enlarge)

Download Instructions

Save the tar file, mintverse.tar to your computer. To extract the files, execute "tar -xvf mintverse.tar" from the directory where you have saved the file.

You will need to compile the MEX function code for your Matlab version - it has been tested on version 6.5. Otherwise you can just use the functions in mintverse.c, primarily the function called int mintverse(...).

For the simple example shown above, simply type, "exampleverse" in Matlab.
Otherwise, "help mintverse" will also help you invoke the functions.

Comments

Please report comments/bugs with this code to Brian Hargreaves.

Last updated Sept 24, 2004