Representation of human tongue motion using three-dimensional vector fields over time can be used to better understand
tongue function during speech, swallowing, and other lingual behaviors. To characterize the inter-subject variability of
the tongue’s shape and motion of a population carrying out one of these functions it is desirable to build a statistical
model of the four-dimensional (4D) tongue. In this paper, we propose a method to construct a spatio-temporal atlas of
tongue motion using magnetic resonance (MR) images acquired from fourteen healthy human subjects. First, cine MR
images revealing the anatomical features of the tongue are used to construct a 4D intensity image atlas. Second, tagged
MR images acquired to capture internal motion are used to compute a dense motion field at each time frame using a
phase-based motion tracking method. Third, motion fields from each subject are pulled back to the cine atlas space using
the deformation fields computed during the cine atlas construction. Finally, a spatio-temporal motion field atlas is
created to show a sequence of mean motion fields and their inter-subject variation. The quality of the atlas was evaluated
by deforming cine images in the atlas space. Comparison between deformed and original cine images showed high
correspondence. The proposed method provides a quantitative representation to observe the commonality and variability
of the tongue motion field for the first time, and shows potential in evaluation of common properties such as strains and
other tensors based on motion fields.
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