Current-induced magnetic resonance phase imaging

Electric current-induced phase alternations have been imaged by fast magnet ic resonance image (MRI) technology. We measured the magnetic resonance pha se images induced by pulsed current stimulation from a phantom and detected its sensitivity. The pulsed current-induced phase image demonstrated the f easibility to detect phase changes of the proton magnetic resonance signal that could mimic neuronal firing. At the present experimental setting, a ma gnetic field strength change of 1.7 +/- 0.3 nT can be detected. We also cal culated the averaged value of the magnetic flux density B-T parallel to B-0 produced by electric current I inside the voxel as a function of the wire position. The results of the calculation were consistent with our observati on that for the same experimental setting the current-induced phase change could vary with location of the wire inside the voxel. We discuss our findi ngs in terms of possible direct MRI detection of neuronal activity, (C) 199 9 Academic Press.