Lisha Yuan1, Yi-Cheng Hsu2, Dan Wu1, Hongjian He1, and Jianhui Zhong1,3
1Center for Brain Imaging Science and Technology, Department of Biomedical Engineering, Key Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, China, 2MR Collaboration, Siemens Healthcare Ltd., Shanghai, China, 3Department of Imaging Sciences, University of Rochester, Rochester, NY, United States
Compared to traditional echo-planar
imaging (EPI)-based schemes, spatiotemporal encoding (SPEN) is largely
insensitive to magnetic field and chemical shift heterogeneities. However,
excitation gradient has different effects for each position, thus the
interaction between imaging and diffusion gradients introduces spatial-dependent
diffusion weightings along the SPEN axis. A new method named polarities average
mode (PAM) was proposed to obtain accurate apparent
diffusion coefficient (ADC) map, with two acquisitions of different polarities
between excitation and diffusion gradients. Simulation, phantom, and human
experiments were designed to assess method performance. The proposed method
enables SPEN to obtain ADC maps easily and accurately.
