Mukund Balasubramanian1, Padma Sundaram1, William W. Wells2, Tobias Loddenkemper3, Robert V. Mulkern1, Darren B. Orbach1
1Department of Radiology, Children's Hospital Boston, Boston, MA, United States; 2Department of Radiology, Brigham and Women's Hospital; 3Department of Neurology, Children's Hospital Boston, Boston, MA, United States
In order to determine the limits of detecting short-duration currents with the phase of gradient-echo EPI, we imaged a phantom carrying ionic currents of various amplitudes and duty cycles, including those approximating epileptiform activity. Our results demonstrate the feasibility of detecting DC pulses with durations of 200 milliseconds or longer, for current amplitudes that are plausible for interictal discharges. Although our particular focus is on epilepsy, the ability to reliably image neuronal currents in general would provide a novel and important contrast mechanism for fMRI, with widespread applicability.