Complex B1+ field-based conductivity mapping in the human myocardium at 3T

Motivation: While electrical property tomography is gaining popularity, cardiac applications are limited due to inadequate cardiac B1+ mapping. Thus, conductivity mapping in the heart using complex B1+ maps is yet unexplored. Goal(s): To measure myocardial conductivity from the complex B1+ distribution in the heart at 3T. Approach: A novel |B1+| mapping method was adapted for free-breathing B1+ maps, followed by conductivity reconstruction via 1D polynomial fitting in saline phantoms and four healthy subjects. Results: Phantom results show excellent correlation with expected values (R2=0.95). In-vivo, conductivity is largely homogenous with 0.69±0.13S/m average in-plane conductivity across all subjects, in line with the literature. Impact: Electrical properties are a valuable biomarker, however, the translation to cardiac imaging remains limited. In this work, complex B1+ field-based conductivity is reported in the human myocardium at 3T, using a novel Bloch-Siegert shift-prepared cardiac B1+ mapping technique.