MRI of the Velopharynx: Clinical Findings in Patients with Velopharyngeal Insufficiency

Abstract

Background: MRI is the only imaging modality capable of directly visualizing the levator veli palatini (LVP) muscles – the primary muscles responsible for velopharyngeal closure during speech. While MRI has been used to describe normal anatomy and physiology of the velopharynx in research studies, there is limited experience with use of MRI in the clinical evaluation of patients with velopharyngeal insufficiency (VPI). Methods: MRI was used to evaluate the velopharyngeal mechanism in patients presenting for VPI management. The MRI followed a fully awake, non-sedated protocol with phonation sequences. Quantitative and qualitative measures of the velopharynx were obtained and compared to age- and sex-matched individuals with normal speech resonance. Results: MRI was successfully completed in 113 of 118 patients (96%). Compared to controls, patients with VPI following cleft palate repair had a shorter velum (p<0.001), higher incidence of LVP discontinuity (p<0.001), and shorter effective velar length (p<0.001). Among patients with persistent VPI after pharyngeal flap placement, findings included a pharyngeal flap base located inferior to the palatal plane (11/15, 73%), shorter velum (p<0.001), and higher incidence of LVP discontinuity (p=0.014). Patients presenting with non-cleft VPI had a shorter (p=0.004) and thinner velum (p<0.001) and higher incidence of LVP discontinuity (p=0.014). Conclusions: MRI provides direct evidence of LVP muscle anomalies and quantitative evaluation of both velar length and velopharyngeal gap. This information is currently unavailable with traditional VPI imaging tools, suggesting MRI may be a useful tool for selecting surgical procedures to address patient-specific anatomic differences.