Hwihun Jeong1, Hyeong-Geol Shin1, Xu Li2, Sooyeon Ji1, and Jongho Lee1
1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea, Republic of, 2Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins Medicine, Baltimore, MD, United States
1Department of Electrical and Computer Engineering, Seoul National University, Seoul, Korea, Republic of, 2Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins Medicine, Baltimore, MD, United States
A new model of resonance
frequency shift that encompasses both susceptibility tensor and chemical exchange
is developed and solved, generating susceptibility tensor and chemical exchange
maps.
Figure 4. In-vivo results of (a) ChEST, (b) MMSR-STI, and (c)
STI reconstructions. The two subject results show similar contrasts in all
maps. In particular, the CE maps show a much smaller contrast range compared to
that of MMS and MSA (see display ranges), confirming our assumption in QSM that
the contribution of CE is much smaller than that of susceptibility.
Figure 1. (a) An illustration of the iterative algorithm for ChEST.
In the first step, STI is conducted from the CE-removed frequency shift map,
producing PEV. Then, the least-squares algorithm is performed while fixing PEV to
derive CE, MMS, and MSA. Through iterations, MMS, MSA, PEV, and CE maps are
reconstructed. (b) The plot of RMSE between the source frequency shift maps and
the reconstructed frequency shift maps in the numerical simulation. The
algorithm converged after 200 iterations.
