Fast B1 mapping based on double-angle method with T1 correction using standard pulse sequence

Yoshiyuki Ishimori, Takeshi Shimanuki, Tomoya Kobayashi, Masahiko MonmaJournal of Medical Physics 2022 47(1):93-98Radiofrequency (RF) field (B1) mapping by combining the double-angle method (DAM) and T1 correction was investigated. The signal intensities S1 and S2 acquired by flip angle (FA) α and double FA 2α at short repetition time (TR) were converted to a signal intensity at TR=∞ by T1 correction. Then, these were used for DAM calculation. The T1 values are measured from two different images acquired with different TRs based on the saturation recovery (SR) method preliminarily. The effects of imaging parameters for T1 estimation and measured FA were investigated using CuSO4-doped water phantoms. A two-dimensional gradient echo type echo planar imaging pulse sequence was used. T1 values obtained by the 2-SR method were underestimated compared to the multipoint inversion recovery method. FA error was less than 5% when the appropriate imaging parameters were used. The acquisition time could be shortened to under 25 s by the use of T1-corrected DAM.

Source: Journal of Medical Physics - March 31, 2022 Category: Physics Authors: Yoshiyuki Ishimori Takeshi Shimanuki Tomoya Kobayashi Masahiko Monma Source Type: research