Ultrasound Current Source Density Imaging (UCSDI) is a new modality for mapping electrical current deep into tissue. This approach combines moderate acoustic pressure with recording electrode technology to directly image current densities. We have demonstrated feasibility of UCSDI in saline, tissue-equivalent phantoms, neural tissue and direct mapping of the cardiac activation wave in the live rabbit heart. Although potential applications of UCSDI are diverse, we are focusing on enhancing electrical cardiac mapping during ablation treatment of arrhythmias.

Potential advantages of UCSDI over conventional electrophysiology and electrical imaging include 1) enhanced spatial resolution determined by the size of the ultrasound focus (<1 mm); and 2) automatic co-registration of UCSDI with pulse echo ultrasound, depicting current density maps superimposed on heart structure and motion.