Simulation and Correction of the Slice Profile Based on SLR Theory in a 0.35 T Permanent MRI System

Abstract

To locate the imaging slice, the hydrogen protons within the selected slice are excited by the coaction of radio-frequency pulse (RF pulse) and slice-selection gradient during the process of magnetic resonance imaging (MRI). However, the absolute consistency of the time between the RF transmitting system and gradient system can’t be guaranteed in an actual magnetic resonance system, which makes the slice profile not ideal enough. Imperfect slice profile will lead to poor imaging quality. In this paper, Shinnar-Le Roux (SLR) theory is used to simulate the slice profile with different relative delays between RF and slice-selection gradient to solve this problem. By matching the actual slice profile with the simulation results, the relative delay is measured in an actual 0.35T permanent magnet MRI system. The practicability of the method is verified for the improvement of image quality after applying the measured delay to correct the actual MRI system.