On the dipolar order underlying broad macromolecular lines

Abstract

International audienceDipolar order has recently regained attention in MRI to analyze dipolar broadened lines in CEST and inhomogeneous Magnetization Transfer (ihMT), leading to new frequency irradiation patterns for enhanced saturation and access to an unexplored degree of freedom. A better understanding of dipolar order is of great interest to guide intuition and may lead to fundamental optimization of the ihMT technique, which is a promising tool providing new tissue contrasts. In this contribution we propose to review this concept, considering a simplified model of isolated proton pairs and the general Provotorov theory of RF saturation which applies to an ensemble of coupled spin