Rationalising spin relaxation during slice-selective refocusing pulses

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Quantitative MRI

Background:

• Slice-selective refocusing pulses are essential in MRI but introduce site-dependent signal loss.
• This attenuation stems from spin relaxation during pulses, influenced by relaxation times, RF pulse shaping, and pulsed field gradients.

Purpose of the Study:

• To develop a method for accurately predicting and correcting signal loss caused by relaxation during slice-selective refocusing pulses in quantitative MRI.

Main Methods:

• The study employed experimental data and numerical simulations.
• An empirical function was developed to model relaxational attenuation.

Main Results:

• Evidence from experiments and simulations demonstrates that a simple empirical function accurately predicts relaxational attenuation.
• This function accounts for complex dependencies on RF pulse shaping and pulsed field gradients.

Conclusions:

• A straightforward empirical approach can effectively correct for relaxational signal losses in quantitative MRI.
• This method has practical implications for improving accuracy in applications like Zangger-Sterk pure shift NMR.