Model for \(B_1\) imaging in MRI using the rotating RF field (Q2262493)

Summary: Conventionally, magnetic resonance imaging (MRI) is performed by pulsing gradient coils, which invariably leads to strong acoustic noise, patient safety concerns due to induced currents, and costly power/space requirements. This modeling study investigates a new silent, gradient coil-free MR imaging method, in which a radiofrequency (RF) coil and its nonuniform field (\(B_1^+\)) are mechanically rotated about the patient. The advantage of the rotating \(B_1^+\) field is that, for the first time, it provides a large number of degrees of freedom to aid a successful \(B_1^+\) image encoding process. The mathematical modeling was performed using flip angle modulation as part of a finite-difference-based Bloch equation solver. Preliminary results suggest that representative MR images with intensity deviations of \(<5\)\% from the original image can be obtained using rotating RF field approach. This method may open up new avenues towards anatomical and functional imaging in medicine.