Rapid whole cerebrum myelin water imaging using a 3D GRASE sequence

Abstract

Myelin water imaging, a magnetic resonance imaging technique capable of resolving the fraction of water molecules which are located between the layers of myelin, is a valuable tool for investigating both normal and pathological brain structure in vivo. There is a strong need for pulse sequences which improve the quality and applicability of myelin water imaging in a clinical setting. In this study, we validated the use of a fast multi echo T(2) relaxation sequence for myelin water imaging. Using a multiple combined gradient and spin echo (GRASE) technique, we attain whole cerebrum myelin water images in under 15 minutes. Region of interest analysis indicates that this fast GRASE imaging sequence produces results which are in good agreement with pure spin echo measurements (R(2)=0.95, p<0.0001). This drastic improvement in speed and brain coverage compared to current spin echo standards will allow increased inclusion of myelin water imaging in neurological research protocols and opens up the possibility of applications in a clinical setting.