John J Heine PhD, Abstract Co-Author: Nothing to Disclose

Ernest Wollin MD, Presenter: Radiologist, Signet Diagnostic Imaging Services President, Wollin Ventures, Inc.

These idealized simulations demonstrate proof of the MREIM concept using relevant operating parameters.

The variable specificity of dynamic contrast enhanced magnetic resonance mammography (DCEMRM) leads to many unnecessary breast biopsies. To address this problem, we are developing both the theoretical foundation and hardware to introduce an electrical impedance biomarker that can be acquired simultaneously with the DCEMRM examination, compatible with, but not requiring, contrast injection. Electrical impedance is a clinically proven biomarker for breast malignancy. We present the general principles of magnetic resonance electrical impedance mammography (MREIM) with computer simulations.

Computer simulations emulate an alternating voltage coupled to the breast during a MRM acquisition using resistive coupling with planar faraday shield electrodes embedded within the stabilization paddles of a standard breast coil. The breast model consists of (1) a uniform background volume of lower electrical conductivity, representing normal tissue, and (2) an embedded spherical volume with greater electrical conductivity, representing a tumor. Simulated currents, voltages, and frequencies are within safe imperceptible ranges. The electrical conductivities are derived from previously published studies. The objective is to produce a differential signal in the region of the simulated malignancy.

MRM magnitude images were simulated using spin echo sequences with frequency encoding along the horizontal direction and phase encoding along the vertical direction. The MREIM effects are observable in the difference image derived by subtracting the raw image from the image acquired with the voltage applied. This difference image shows an edge effect and extended spatial effect, as predicted by the theory.

Heine, J, Wollin, E, Magnetic Resonance Electrical Impedance Mammography (MREIM): Computer Simulation of Clinical Applications and Theoretical Analysis.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034221.html