RF pulse design for MRI of samples including conductive implants

Magnetic resonance imaging (MRI) of patients having a conductive implant causes interference with internal RF magnetic fields. The interference results in a signal loss around the implant. In this study, we propose an MRI acquisition method to recover the signal loss using the RF pulse for spatially designed excitation. Based on the measured distribution of RF magnetic field, the Bloch equation was inversely solved to design the waveform of RF pulse for improving the homogeneity of flipped magnetization. MRI acquisitions were performed with phantoms including metallic implants made from copper and aluminum. The results show that the designed waveform of RF pulse improves the homogeneity of signal intensity in MRI, and the signal loss around the metals was recovered.