Electromagnetic-Acoustic Modeling of Fields Induced by Gradient Pulses in Diffusion Tensor Magnetic Resonance Imaging

摘要

Diffusion tensor magnetic resonance imaging (DT-MRI) has recently gained popularity because of its capabilities in axonography of the central nervous system. Fast imaging sequences are used to reduce motion induced distortion effects on the diffusion signal, resulting in low signal levels, loud acoustic noise, and occasional peripheral nerve stimulation. Eddy current induced by diffusion gradient pulses is also a challenge to DT-MRI. Magnetic field associated with the eddy current is a major source of artifacts in scanner images. This paper introduces a finite element modeling of electromagnetic and acoustic fields in DT-MRI sequences. The analysis involves three dimensional modeling of the scanner and its interaction with pulses applied to gradient coils. Efficient modeling of induced fields is essential in optimizing parameter settings and improving performance of this imaging modality.