Multi-echo spin-, asymmetric spin-, and gradient-echo echo-planar imaging mri pulse sequence

Abstract

An echo planar imaging technique in which a quadruple echo gradient and spin echo echo-planar imaging pulse sequence is utilized. The pulse train includes generation of two echo trains between an excitation pulse (90) and a refocusing pulse (180) to achieve two gradient echo images (also called T2*-weighted images); with one echo train directly after the 180 pulse, leading to asymmetric spin echo images (T2'-weighted images); and a last echo train afterward that generates spin echo images (T2-weighted). The technique has a number of advantages over existing techniques with regard to voxel size, mapping relative oxygen extraction, determining permeability, determining relative cerebral blood volume, vessel parameters (diameter, density, size, arterial/venous, etc.), stroke imaging, imaging perfusion, fMRI imaging, and additional benefits.