State-of-the-Art MRI Protocol for Comprehensive Assessment of Vocal Tract Structure and Function

Magnetic Resonance Imaging (MRI) provides a safe and flexible means to study the vocal tract, and is increasingly used in speech production research. This work details a state-ofthe-art MRI protocol for comprehensive assessment of vocal tract structure and function, and presents results from representative speakers. The system incorporates (a) custom upper airway coils that are maximally sensitive to vocal tract tissues, (b) graphical user interface for 2D real-time MRI that provides on-the-fly reconstruction for interactive localization, and correction of imaging artifacts, (c) off-line constrained reconstruction for generating high spatio-temporal resolution dynamic images at (83 frames per sec, 2.4 mm), (d) 3D static imaging of sounds sustained for 7 sec with full vocal tract coverage and isotropic resolution (resolution: 1.25 mm), (e) T2-weighted high-resolution, high-contrast depiction of soft-tissue boundaries of the full vocal tract (axial, coronal, sagittal sweeps with resolution: 0.58 x 0.58 x 3 mm), and (f) simultaneous audio recording with off-line noise cancellation and temporal alignment of audio with 2D real-time MRI. A stimuli set was designed to capture efficiently salient, static and dynamic, articulatory and morphological aspects of speech production in 90minute data acquisition sessions.