Coregistration of Electrical Impedance Tomography and Magnetic Resonance Imaging

Abstract

There has been moderate success in using elec- trical impedance tomography (EIT) to image changing imped- ances within the body, such as with pulmonary imaging. Abso- lute impedance imaging of static physiology has, however been more challenging primarily due to imprecise measurements and modeling errors associated with image reconstruction. At Dartmouth, we have been using EIT to generate images of the absolute impedance distribution of breast. Here we report on our recent efforts to improve the clinical intrepretation of EIT images by correlating them directly with magnetic resonance (MR) images. We have conducted a set of experiments in which EIT and MR images were obtained from a volunteers forearm. A qualitative analysis of the coregistered MR and EIT images is presented and we discuss how well absolute imaging with EIT is able to correctly characterize a physio- logical system. Further, we have conducted a set of experi- ments in which a circular electrode array was placed within a 3T MR imaging system and both EIT and MR images were obtained of a gelatine phantom. These experiments confirmed that dual-modality imaging (EIT/MRI) is possible. Based on these results, we finally discuss what we consider to be the possible benefits gained using a coupled imaging system such as this in a clinical setting.