Simultaneous T1 and B1+ Mapping Using Reference Region Variable Flip Angle Imaging
Article first published online: 13 AUG 2013
Copyright © 2013 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine
Volume 70, Issue 4, pages 954–961, October 2013
How to Cite
Sung, K., Saranathan, M., Daniel, B. L. and Hargreaves, B. A. (2013), Simultaneous T1 and B1+ Mapping Using Reference Region Variable Flip Angle Imaging. Magn Reson Med, 70: 954–961. doi: 10.1002/mrm.24904
- Issue published online: 24 SEP 2013
- Article first published online: 13 AUG 2013
- Manuscript Revised: 5 JUL 2013
- Manuscript Accepted: 5 JUL 2013
- Manuscript Received: 19 FEB 2013
- NIH . Grant Number: R01-EB009055
- B1 field inhomogeneity;
- T1 mapping;
- quantitative DCE-MRI;
- breast imaging;
- high-field MRI
To present a new method that can simultaneously and efficiently measure T1 and B1+ maps using reference region variable flip angle (RR-VFA) imaging.
Assuming T1 relaxation time in a reference region such as fat is well characterized, and the reference region sufficiently covers smoothly varying B1+ field inhomogeneity, B1+ maps can be measured from VFA images, conventionally used for T1 measurements. Fat-only images from two-point Dixon acquisitions were used to compute B1+ maps, and the B1+ maps were compared with ones using the double-angle method (DAM) in 22 breast MRI patients at 3T. Additionally, high spatial resolution VFA images were acquired to show T1 measurements with and without the RR-VFA B1+ correction in six patients.
RR-VFA is able to generate reliable B1+ maps, similar to those using the conventional DAM. This simultaneous T1 and B1+ mapping can also be used to reduce T1 estimation errors, where T1 maps have more uniform fibroglandular tissue T1 and better depiction of heterogeneous T1 of breast masses.
A new method that can measure both T1 and B1+ maps based on Dixon VFA images is described, offering improved T1 quantification with no scan time penalty. Magn Reson Med, 70:954–961, 2013. © 2013 Wiley Periodicals, Inc.