4D Dynamic-MRI as Glossectomy Speech Assessment Tool

Abstract

Objective: Quantitative tools assessing functional outcomes after tongue cancer treatment are crucial for evaluation and comparison of surgical reconstruction techniques or chemoradiation protocols. Furthermore, tools measuring physiologic outcomes directly and specifically may lead to a better understanding of tongue adaptation control. We developed a 4D dynamic MRI to address these issues.

Method: This MRI tool included 2 components: 1) A static 3D high-resolution MRI to identify structures spared from the surgery. 2) Dynamic cine- and tagged-MRI scans at 26 frames/second to determine the tongue surface and measure point displacement during speech. Data were collected from 3 patients and 3 controls.

Results: The 3D segmentation of the residual muscles were compared to the controls. Twenty-six 3D tongue volumes with surface deformation during the utterance of the word /asouk/ showed that patients adapt their tongue shape for /S/. The medial grooving seen in controls is deviated to the surgical side and the lateral sides of the anterior tongue make palatal and dental contact in patients. The 3D tagged MRI in patients showed asymmetrical displacement in several distinct parts of the tongue not seen in controls. The local distinct pattern suggests local adaptation for utmost speech performance. All patients had above 98% intelligibility scores.

Conclusion: This is the first study of 4D-MRI relating residual tongue anatomy to 3D surface and internal kinematics during speech. This technique may provide a future predictive model for treatment options.