Relationships between nasalance scores and nasopharyngeal shapes in cleft palate patients

Establishing a Clinical Protocol for Velopharyngeal MRI and Interpreting Imaging Findings

Traditional imaging modalities used to assess velopharyngeal insufficiency (VPI) do not allow for direct visualization of underlying velopharyngeal (VP) structures and musculature which could impact surgical planning. This limitation can be overcome via structural magnetic resonance imaging (MRI), the only current imaging tool that provides direct visualization of salient VP structures. MRI has been used extensively in research; however, it has had limited clinical use. Factors that restrict clinical use of VP MRI include limited access to optimized VP MRI protocols and uncertainty regarding how to interpret VP MRI findings. The purpose of this paper is to outline a framework for establishing a novel VP MRI scan protocol and to detail the process of interpreting scans of the velopharynx at rest and during speech tasks. Additionally, this paper includes common scan parameters needed to allow for visualization of velopharynx and techniques for the elicitation of speech during scans.

Measurement Matters: MRI Analysis of Differing Anatomic Measurement Techniques for Velar Length and the Velopharyngeal Needs Ratio

Background

Advances in imaging tools provide opportunities to enhance how velopharyngeal (VP) variables are quantified to facilitate surgical decisions. The purpose of this study was to use magnetic resonance imaging (MRI) to determine if quantitative differences were present between measures of linear and curvilinear velar length, and subsequently, the VP needs ratio.

Methods

Data were prospectively collected from patients presenting with repaired cleft palate and/or congenital palatal insufficiency with or without VPI at a single center tertiary children's hospital. Quantitative measures of the velopharynx using a novel nonsedated MRI protocol were obtained. Paired samples t tests were conducted to assess if differences were present between the VP needs ratio and measurements of linear and curvilinear velar length at rest and during sustained phonation. Intraclass correlation coefficients were calculated to assess intra/inter-rater reliability.

Results

Significant differences were present between measurements of linear and curvilinear velar length at rest (P ≤ 0.001) and during sustained phonation (P ≤ 0.001). Significant differences were also present in the VP needs ratio (P ≤ 0.001). Curvilinear velar length at rest and during sustained phonation was longer than that of linear velar length at rest and during sustained phonation. No significant differences were observed between measures of effective velar length (P = 0.393).

Conclusions

Measurement differences influence the VP needs ratio. This may have implications for comparisons to previously reported normative reference values and for those who are anatomically at risk for VPI. MRI provides an enhanced imaging modality to assess normative benchmarks and the anatomic variables used to define VP anatomy for clinical decision-making.

Effective Velopharyngeal Ratio: A More Clinically Relevant Measure of Velopharyngeal Function

Purpose Velopharyngeal (VP) ratios are commonly used to study normal VP anatomy and normal VP function. An effective VP (EVP) ratio may be a more appropriate indicator of normal parameters for speech. The aims of this study are to examine if the VP ratio is preserved across the age span or if it varies with changes in the VP portal and to analyze if the EVP ratio is more stable across the age span. Method Magnetic resonance imaging was used to analyze VP variables of 270 participants. For statistical analysis, the participants were divided into the following groups based on age: infants, children, adolescents, and adults. Analyses of variance and a Games-Howell post hoc test were used to compare variables between groups. Results There was a statistically significant difference (p < .05) in all measurements between the age groups. Pairwise comparisons reported statistically significant adjacent group differences (p < .05) for velar length, VP ratio, effective velar length, adenoid depth, and pharyngeal depth. No statistically significant differences between adjacent age groups were reported for the EVP ratio. Conclusions Results from this study report the EVP ratio was not statistically significant between adjacent age groups, whereas the VP ratio was statistically significant between adjacent age groups. This study suggests that the EVP ratio is more correlated to VP function than the VP ratio and provides a more stable and consistent ratio of VP function across the age span.