Extended phase graph formalism for systems with magnetization transfer and exchange.

ABSTRACT:

Purpose

An extended phase graph framework (EPG-X) for modeling systems with exchange or magnetization transfer (MT) is proposed.

Theory

EPG-X models coupled two-compartment systems by describing each compartment with separate phase graphs that exchange during evolution periods. There are two variants: EPG-X(BM) for systems governed by the Bloch-McConnell equations, and EPG-X(MT) for the pulsed MT formalism. For the MT case, the "bound" protons have no transverse components, so their phase graph consists of only longitudinal states.

Methods

The EPG-X model was validated against steady-state solutions and isochromat-based simulation of gradient-echo sequences. Three additional test cases were investigated: (i) MT effects in multislice turbo spin-echo; (ii) variable flip

SUBMITTER: Malik SJ 

PROVIDER: S-EPMC5947218 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature