Advancing MRI of the tongue:Imaging muscular architecture and swallowing functionality

Abstract

In patients with oral or oropharyngeal cancer the functionality of the tongue may become severely affected by the treatment of the cancer. In order plan tongue cancer treatment with minimal loss of functionality, the patient’s tongue functionality after treatment can be estimated by biomechanical modelling. This model is constructed from post-mortem data of a different individual. However, the biomechanical model should be personalised using information of the tongue’s muscular architecture in order to better estimate the port-treatment functionality.Therefore, we applied the MRI method constrained spherical deconvolution (CSD) to the tongue, which resulted in accurate in-vivo reconstructions of the tongue’s muscular architecture. Subsequently, using a CSD-based registration algorithm we generated population averages of CSD images of in-vivo tongues. These averages served as the template from which we were able to automatically generate personalised biomechanical models of the tongue. These models predicted the range-of-motion of the tongues more accurately than a generic model.Although promising, the largest draw-back of CSD MRI is the long scan time, which increases the chance of motion artefacts distorting the images. Therefore, we designed and built a custom MRI receiver coil for tongue imaging. Using this coil, we were able to halve the scan time of a CSD scan. Furthermore, this acceleration provided by the custom coil allowed us to develop a real-time MRI sequence, resulting in three-dimensional videos of swallowing at a frame rate of 12 frames per second