Use of the Relationship between Phase & Magnetic Susceptibility for Assessment of Assumed Contrast Agent Distributions In Vivo: Application to δR2* Maps in Dynamic Susceptibility Contrast MRI

Emelie Lindgren¹, Linda Knutsson¹, Danielle van Westen², Freddy Sthlberg^1,3, Ronnie Wirestam¹

Magnetic susceptibility quantification by deconvolution of measured phase maps is an interesting approach, although the method constitutes an ill-posed inverse problem to which an ideal solution is presently lacking. An interesting intermediate step is to compare measured phase maps (reflecting true local susceptibility) with artificial phase maps calculated by convolution of an assumed susceptibility distribution. Delta_R2* maps were assumed to represent contrast agent concentration (i.e., proportional to susceptibility), as is traditionally the case in DSC-MRI. Differences between measured and artificial phase maps were observed, not inconsistent with different T2* relaxivities in different compartments, as predicted by previously published simulation studies.