Analysis of Peak Velocity and Mean Velocity According to Shimming Technique in 2D Phase Contrast : Comparison of 1.5 Tesla and 3.0 Tesla

Abstract

The purpose of this study was to compare the difference in peak velocity (PV) and average flow (AF) values between the shimming of the aortic arch (AA) and the left ventricle (LV) using the 2D phase contrast (PC) technique at 1.5 Tesla and 3.0 Tesla. The sino-tubular junction (S-T junction), the proximal AA, and the LV, an aortic valve, were examined using a 2D PC technique at 1.5 Tesla and 3.0 Tesla. At 1.5 Tesla and 3.0 Tesla, 2D PC technique was used to examine the proximal AA Sino-Tubular (S-T) junction and LV was examined at the aortic valve area. shim was not used (no_Shim) in 1.5 Tesla and 3.0 Tesla to compare differences in heart blood flow due to magnetic field strength. To assess the difference due to shimming, an auto_shim, target_shim was used and an all_shimthat used auto and target shim simultaneously was used. The average value between 1.5 Tesla and 3.0 Tesla as a result of inspection was different when AA_AF was no_shim and all_shim. In LV_AF, the difference in mean values was found in 1.5 Tesla and 3.0 Tesla when it was no_shim and all_shim. Other tests did not show any significant differences. Also, according to the shimming method in 1.5 Tesla, the mean value difference occurred in AA_AF and the mean value difference in LV_AF in 3.0 Tesla. In conclusion, it is necessary to improve uniformity of magnetic field through shimming for accurate blood flow evaluation in 1.5 Tesla and 3.0 Tesla. Therefore, this study is expected to be used as a basis for improving the uniformity of magnetic field.