In utero fetal brain diffusion weighted imaging

Introduction Fetal MR brain imaging is proving to be a powerful modality with which to evaluate the developing fetal brain. Advanced imaging strategies, such as diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) have recently been applied to the human fetus [1,2]. The major difficulty of performing DWI of the fetal brain in utero is the presence of motion, which is especially marked during the second and early third trimester when most clinical fetal MRI is performed. Maternal breathing can also contribute to motion degradation since image acquisition requires the mother to hold her breath. While breath hold single shot acquisitions have been predominantly used for fetal DWI, this technique alone cannot provide the robustness needed against unpredictable fetal motion and motion due to maternal breathing. Therefore, the goal of this study was to devise a DWI technique, capable of obtaining trace ADC maps (Dav; averaged ADC), with reduced susceptibility to motion, that could be used to image the fetal brain in the clinical setting. In addition, the possibility of extending the study to acquire DTI was also investigated.