An apparatus includes a magnetic energy source to provide a magnetic signal and a detector to detect an acoustic energy signal from a sample stimulated by the magnetic energy signal. A method includes applying a magnetic signal to a biological sample, detecting an acoustic signal from the sample, and processing the acoustic signal to determine the electrical impedance distribution of the sample, and identify disease in the biological sample. A method includes applying a magnetic signal to a sample, detecting a magnetic or electrical signal within the sample, and processing the magnetic or electrical signal to reconstruct electrical impedance distribution of the sample.