MRI B0 and B1 Map Correction for Conductivity Accuracy

The patent segments the imaging process into distinct components: acquiring B0 inhomogeneity maps, acquiring B1 phase maps, calculating geometric distortion corrections, and applying these corrections to derive accurate electrical properties. This segmentation allows each component to be optimized independently while maintaining overall system productivity.

The patent performs preliminary calculations of B0 inhomogeneity maps and geometric distortion corrections before conducting the main conductivity mapping. By pre-characterizing the field inhomogeneities and computing correction factors in advance, the method eliminates the need for repeated corrective measurements during the main imaging sequence, thus maintaining productivity while improving precision.

The patent calculates the geometric distortion correction factors and adjusted voxel sizes in advance using pre-acquired B0 maps. These correction parameters are stored and reused during the main imaging sequence, eliminating the need for real-time calculation of distortion corrections and their derivatives, thus reducing processing time while maintaining accuracy.

The system uses its own acquired B0 inhomogeneity data to generate the correction factors it needs, making the process self-sufficient. The B0 maps acquired during the imaging session are directly used to compute the geometric distortion corrections for that same session, eliminating the need for external calibration data or complex reference measurements.

The patent employs the n-point Dixon method to simultaneously acquire multiple pieces of information: B0 inhomogeneity maps, B1 phase maps, and water-fat separation data all in a single multi-echo sequence. This multi-functionality allows reliable field mapping without requiring separate dedicated sequences for each parameter, thus maintaining productivity while improving reliability.

The patent maintains continuous data acquisition across multiple echoes in the Dixon sequence, where each echo contributes additional information for robust B0 and B1 estimation. By continuously acquiring data rather than using discrete separate measurements, the method achieves high reliability through multiple samples while minimizing total scanning time through efficient use of each echo.