3D Ultrasound Backscatter Tensor Imaging (3D-BTI) is a novel approach based on 3D Ultrafast Ultrasound Imaging to map fiber orientation in tissues such as the human heart in vivo [1]. Fiber orientations are obtained in entire volumes at high frame rate by computing and analyzing a voxel-wise coherence function relying on the synthetic focusing of multiple tilted plane waves. However, in rapidly moving organs such as the heart, the quality of the synthetic focusing and thus of the computed fiber orientation will be altered by motion. In this study, we quantify the effect of axial tissue motion on the quality of 2D spatial coherence functions, propose a novel motion-correction scheme, and demonstrate its application.