Characterization of the cardiac conduction system with inhomogeneous Magnetization Transfer (ihMT): an ex-vivo study

Motivation: Imaging the cardiac conduction system (CCS) remains a significant challenge, since no imaging modalitiy has so far provided good contrast between the cardiac muscle and the embedded fibers that regulate normal heartbeat. Goal(s): We aim to address this challenge by employing inhomogeneous Magnetization Transfer Imaging (ihMT). Approach: We hypothesise that the conductive fibers exhibit unique dipolar order properties, due to the collagen sheath that surrounds them, and could thus be selectively isolated by ihMT. Results: As a first step towards enhancing muscle-to-fiber contrast, this work investigated the biophysical parameters that govern the ihMT signal in the macromolecular environment of the CCS. Impact: The assessment of the macromolecular environment of the cardiac conduction system (CCS) allows for a better understanding of its morphological architecture, and will enable us to design an ihMT sequence specifically sensitive to the challenging morphology of the CCS.