Magnetic resonance imaging assessment of the velopharyngeal mechanism at rest and during speech in Chinese adults and children

Incorporating Velopharyngeal MRI into the Clinical Decision-Making Process for a Patient Presenting with Velopharyngeal Dysfunction Following a Failed Palatoplasty

This clinical report describes the implementation of magnetic resonance imaging (MRI) to evaluate a patient with long-standing velopharyngeal dysfunction. She was referred to the craniofacial clinic at age 10 with no prior surgical history and subsequently completed a Furlow palatoplasty due to a suspected submucous cleft palate. However, results were unfavorable with minimal improvement in speech or resonance. The clinical presentation, treatment, outcomes, and contributions from MRI for secondary surgical planning are described. Addition of MRI into the clinical workflow provided insights into the anatomy and physiology of the velopharyngeal mechanism that were unable to be obtained from nasendoscopy and speech evaluation alone.

Three-dimensional finite element analysis on stress distribution after different palatoplasty and levator veli palatini muscle reconstruction

OBJECTIVES

To establish a three-dimensional finite element model of the upper palate, pharyngeal cavity, and levator veli palatini muscle in patients with unilateral complete cleft palate, simulate two surgical procedures that the two-flap method and Furlow reverse double Z method, observe the stress distribution of the upper palate soft tissue and changes in pharyngeal cavity area after different surgical methods, and verify the accuracy of the model by reconstructing and measuring the levator veli palatini muscle.

MATERIALS AND METHODS

Mimics, Geomagic, Ansys, and Hypermesh were applied to establish three-dimensional finite element models of the pharyngeal cavity, upper palate, and levator veli palatini muscle in patients with unilateral complete cleft palate. The parameters including length, angle, and cross-sectional area of the levator veli palatini muscle etc. were measured in Mimics, and two surgical procedures that two-flap method and Furlow reverse double Z method were simulated in Ansys, and the area of pharyngeal cavity was measured by hypermesh.

RESULTS

A three-dimensional finite element model of the upper palate, pharyngeal cavity, and bilateral levator veli palatini muscle was established in patients with unilateral complete cleft palate ; The concept of horizontal projection characteristics of the palatal dome was applied to the finite element simulation of cleft palate surgery, vividly simulating the displacement and elastic stretching of the two flap method and Furlow reverse double Z method during the surgical process; The areas with the highest stress in the two-flap method and Furlow reverse double Z method both occur in the hard soft palate junction area; In resting state, as measured, the two flap method can narrow the pharyngeal cavity area by 50.9%, while the Furlow reverse double Z method can narrow the pharyngeal cavity area by 65.4%; The measurement results of the levator veli palatini muscle showed no significant difference compared to previous studies, confirming the accuracy of the model.

CONCLUSIONS

The finite element method was used to establish a model to simulate the surgical procedure, which is effective and reliable. The area with the highest postoperative stress for both methods is the hard soft palate junction area, and the stress of the Furlow reverse double Z method is lower than that of the two-flap method. The anatomical conditions of pharyngeal cavity of Furlow reverse double Z method are better than that of two-flap method in the resting state.

CLINICAL RELEVANCE

This article uses three-dimensional finite element method to simulate the commonly used two-flap method and Furlow reverse double Z method in clinical cleft palate surgery, and analyzes the stress distribution characteristics and changes in pharyngeal cavity area of the two surgical methods, in order to provide a theoretical basis for the surgeon to choose the surgical method and reduce the occurrence of complications.

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.

Real-time speech MRI datasets with corresponding articulator ground-truth segmentations

The use of real-time magnetic resonance imaging (rt-MRI) of speech is increasing in clinical practice and speech science research. Analysis of such images often requires segmentation of articulators and the vocal tract, and the community is turning to deep-learning-based methods to perform this segmentation. While there are publicly available rt-MRI datasets of speech, these do not include ground-truth (GT) segmentations, a key requirement for the development of deep-learning-based segmentation methods. To begin to address this barrier, this work presents rt-MRI speech datasets of five healthy adult volunteers with corresponding GT segmentations and velopharyngeal closure patterns. The images were acquired using standard clinical MRI scanners, coils and sequences to facilitate acquisition of similar images in other centres. The datasets include manually created GT segmentations of six anatomical features including the tongue, soft palate and vocal tract. In addition, this work makes code and instructions to implement a current state-of-the-art deep-learning-based method to segment rt-MRI speech datasets publicly available, thus providing the community and others with a starting point for developing such methods.

Does the Type of MRI Sequence Influence Perceived Quality and Measurement Consistency in Investigations of the Anatomy of the Velopharynx?

PURPOSE

The purpose of this study was to evaluate perceived image quality, confidence in identifying key velopharyngeal landmarks, and reliability of making velopharyngeal measures between 3-dimensional (3-D) and 2-D magnetic resonance imaging (MRI) methods and between T1-, T2-, and proton density (PD)-weighted sequences.

METHODS

Twelve healthy participants completed an MRI study. Three raters assessed overall image quality and their ability to identify key anatomic features within the images. A single rater evaluated the reliability of making measures between imaging methods and sequence types to determine if image type (2-D and 3-D) or image sequence (T1, T2, PD weighted) resulted in different values for key velopharyngeal landmarks.

RESULTS

An analysis of variance test revealed image quality was rated significantly different based on the scan type (P < .001) and the sequence used (P = .015). Image quality was rated higher among 2-D MR images compared to 3-D, and higher among T2 sequences compared to T1- and PD-weighted imaging methods. In contrast, raters favored 3-D sequences over 2-D sequences for identifying velopharyngeal landmarks. Measures of reliability revealed scan type significantly impacted 2 of the 6 variables but to a minimal degree; however, sequence type had no impact on measures of reliability across all variables.

CONCLUSION

Results of the study suggest the scan type and sequence used are factors that likely do not impact the reliability of measures. Based on image quality, the recommended technique for velopharyngeal imaging would be using a 2-D T2-weighted technique. However, based on the ability to identify key landmarks, a 3-D T1- or PD-weighted technique was favored.

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.

Contracted Extravelar Segments of the Levator Veli Palatini Muscle: A Magnetic Resonance Imaging Morphometric Study

OBJECTIVES

To provide detailed descriptions of contraction-induced morphometric changes in the extravelar segments of the levator veli palatini (LVP) muscle using 3-dimensional (3-D) magnetic resonance imaging (MRI).

DESIGN

Three-dimensional MRI data were acquired at rest and during "silent /i/" from 4 singers. During silent /i/, participants voluntarily sustained velar elevation while breathing orally for the entire scan time. Focusing on the extravelar segments, LVP length, angle of the muscle origin, and cross-sectional area (CSA), measurements were obtained and compared between tasks.

RESULTS

Three of the 4 participants exhibited the expected patterns of change following concentric contraction of the LVP muscle. Consistent changes from the resting to the contracted state included reductions in LVP length by 13.5% and angle of the muscle origin by 9.8%, as well as increases in CSAs by 22.1%, on average.

CONCLUSIONS

This study presented high-resolution data of the LVP muscle behavior with the first in vivo 3-D measurements of the contracted LVP muscle, which can be useful for the validation of computational models that aim at describing biomechanical properties of the LVP muscle in future research. The active behavior of the extravelar LVP muscle also provides some insight on optimal LVP muscle geometry to consider during cleft palate repair.

Asymmetry and Positioning of the Levator Veli Palatini Muscle in Children With Repaired Cleft Palate

Purpose The purpose of this study is to examine the differences in velopharyngeal dimensions as well as levator veli palatini (levator) muscle morphology, positioning, and symmetry of children with repaired cleft palate with velopharyngeal insufficiency (VPI), children with repaired cleft palate with complete velopharyngeal closure, and children with noncleft anatomy. Method Fifteen children ranging in age from 4 to 8 years were recruited for this study. Ten of the participants had a history of repaired cleft palate, half with documented VPI and the other half with velopharyngeal closure. Five participants with noncleft anatomy were matched for age from a normative database. The magnetic resonance imaging protocol, processing methods, and analysis are consistent with that used in previous literature. Results Regarding velopharyngeal dimensions, median values were statistically significantly different between groups for sagittal angle (p = .031) and effective velopharyngeal ratio (p = .013). With respect to the levator muscle, median values were statistically significant for average extravelar length (p = .018), thickness at midline (p = .021), and thickness between the left and right muscle bundles at the point of insertion into the velum (p = .037). Remaining measures were not statistically significant. Conclusions The levator muscle is significantly different among these three groups with respect to thickness at midline, extravelar length, and symmetry at the point of insertion into the velum. Sagittal angle and effective velopharyngeal ratio are also significantly different. Participants with repaired cleft palate and VPI displayed the greatest degree of asymmetry. Future research should control for surgical procedure type to determine the impact of surgery on the levator muscle and surrounding velopharyngeal anatomy.

Velopharyngeal Structural and Muscle Variations in Children With 22q11.2 Deletion Syndrome: An Unsedated MRI Study

Objective:

The 22q11.2 deletion syndrome (22q11.2DS) is the most common genetic cause of velopharyngeal dysfunction; however, limited information exists regarding variations in velopharyngeal anatomy in this clinically challenging population. The purpose of this study was to examine velopharyngeal characteristics among young children with 22q11.2DS in comparison to a normative cohort using an innovative, nonsedated magnetic resonance imaging (MRI) scanning protocol.

Methods:

Fifteen children with 22q11.2DS and 15 age- and gender-matched controls with normal velopharyngeal anatomy (ages 4-12) successfully completed the MRI protocol. Eighteen velopharyngeal and 2 related craniofacial measures were examined. Analysis of covariance was used to compare differences between the experimental and the control groups.

Results:

The 22q11.2DS group demonstrated a significantly thinner velum ( P < .0005) and a larger pharyngeal depth ( P = .007) compared to the matched control group. Findings in the current study also demonstrated that the levator veli palatini muscle is significantly shorter ( P = .037) and thinner ( P = .025) in the 22q11.2DS cohort, with a significantly shorter origin-to-origin distance ( P < .0005) and a greater angle of origin ( P = .001) compared to healthy peers.

Conclusion:

Children with 22q11.2DS demonstrated multiple variations that may contribute to velopharyngeal dysfunction by altering the anatomic characteristics of the velopharyngeal port, the levator muscle, and associated structures. This investigation represents the first and largest attempt to characterize velopharyngeal anatomy in children with 22q11.2DS using a nonsedated MRI protocol.

Effects of Surgical Intervention and Continuous Positive Airway Pressure Therapy on Velopharyngeal Structure and Function: A Case Report

Changes to the velum and velopharyngeal muscles following Furlow double-opposing Z-plasty in a 7-year-old female with submucous cleft palate and velopharyngeal dysfunction (VPD) were evaluated. Perceptual, instrumental (ie, nasometry and aerodynamic pressure flow), and research magnetic resonance imaging analyses were used during pre- and postsurgical time points at a university research clinic. Continuous positive airway pressure (CPAP) therapy was trialed following a failed surgery for residual VPD in the patient. Increases in velar length and thickness and decreases in levator veli palatini muscle angle of origin and contraction were observed following the Furlow double-opposing Z-plasty surgery. Variable improvements in residual hypernasality following the home-based CPAP therapy protocol were observed.

Effect of motor-based speech intervention on articulatory placement in the treatment of a posterior nasal fricative: a preliminary MRI study on a single subject

BACKGROUND

Posterior nasal fricatives are a learned compensatory articulation error and commonly substituted for oral fricatives. Treatment of such articulation errors requires the modification or teaching of skilled movements. A motor-based approach is designed to teach the complex motor skill movement sequences required in the production of sounds. Although motor learning research is well established, little has been done to determine how the approach changes the underlying physiology of articulatory movements. While the underlying anatomical configuration of the posterior nasal fricative has been described, no studies have quantified anatomic and physiological changes pre- and post-treatment.

AIMS

To use magnetic resonance imaging (MRI) to visualize and quantify the results of motor-based speech-intervention approach on articulatory placement for the treatment of the posterior nasal fricative.

METHODS & PROCEDURES

A 6-year-old male with a history of ear infections and posterior nasal fricative substitution for /s/ underwent six 1-h sessions of a motor-based treatment approach over the course of 2 weeks. Pre- and post-treatment evaluation included perceptual and instrumental assessment of speech and resonance. Perceptual resonance was rated by two speech-language therapists and articulation was assessed at the single-word level. Instrumental assessment included the See-Scape, Nasometer II and MRI during the sustained phonation of /s/. Amira v5.6 Visualization and Volume modelling software used the midsagittal and oblique coronal plane to measure dimensions of the articulatory anatomy.

OUTCOMES & RESULTS

Interrater reliability was assessed using a Pearson product moment correlation (α = .05) and ranged from r = .91 to .95. Intra-rater reliability was assessed using the intra-class correlation coefficient (.976) demonstrating a high degree of reliability with a 95% confidence interval. Articulation improved from 0% accuracy for /s/ in isolation at baseline to 100% for /s/ at the word level and 95% accuracy during conversational speech by session 6. Post-treatment results from this study revealed a greater shortening of the levator veli palatini (levator) muscle length during articulatory movements, more pronounced velar knee and dimple, decreased velar thickness, increased velar length and altered tongue position.

CONCLUSIONS & IMPLICATIONS

This study demonstrated the use of pre- and post-treatment imaging methodology to quantify articulatory changes following an intensive motor-based treatment approach. MRI demonstrated quantifiable changes in articulatory placement. Individuals who exhibit non-developmental and phoneme-specific articulation errors, such as the posterior nasal fricative, may be excellent candidates for short-term, intensive and frequent speech therapy sessions to remediate the production of the posterior nasal fricative.

Morphology of the Levator Veli Palatini Muscle in Adults With Repaired Cleft Palate

The purpose of this study was to examine differences in levator veli palatini (levator) morphology between adults with repaired cleft palate and adults with noncleft anatomy. Fifteen adult participants (10 with noncleft anatomy, 5 with repaired cleft palate) underwent 3-dimensional (3D) static magnetic resonance imaging (MRI). Image analyses included measures of total muscle volume and the circumference and diameter at 6 points along the length of the muscle. Differences between groups were analyzed using independent sample Mann-Whitney U tests (α < 0.05). Significant differences between groups were noted for measures of muscle volume, circumference at the origin and midline, anterior-posterior diameter at the origin and midline, and superior-inferior diameter at the point of insertion into the velum and midline. Differences in measures at other points along the levator muscle belly were not statistically significant. Limited sample size and gender differences may have impacted statistical findings. Overall, the levator muscle in adults with repaired cleft palate is significantly different than that of adults with noncleft anatomy. This study demonstrates the successful implementation of a method for 3D analysis of velopharyngeal (VP) musculature with potential clinical utility given continued technological advancements in MRI. Continued evaluation of pre- and postsurgical anatomy and short- and long-term outcomes may contribute to a better understanding of the effects of various types of palatoplasties on levator structure, which is important to VP function for speech.

Examining a New Method to Studying Velopharyngeal Structures in a Child With 22q11.2 Deletion Syndrome

PURPOSE

To date, no studies have imaged the velopharynx in children with 22q11.2 deletion syndrome (22q11.2 DS) without the use of sedation. Dysmorphology in velopharyngeal structures has been shown to have significant negative implications on speech among these individuals. This single case study was designed to assess the feasibility of a child-friendly magnetic resonance imaging (MRI) scanning protocol in this clinically challenging population and to determine the utility of this MRI protocol for future work in this area.

METHOD

One 6-year-old White girl diagnosed with 22q11.2 DS was imaged using a child-friendly, nonsedated MRI protocol. Quantitative and qualitative measures of the velopharyngeal area and associated structures were evaluated, and comparisons were made to age-matched control subjects with normal velopharyngeal anatomy.

RESULTS

MRI data were successfully obtained using the child-friendly scanning protocol in the subject in the present study. Quantitative and qualitative differences of the levator muscle and associated velopharyngeal structures were noted. Using these MRI and structural analyses methods, insights related to muscle morphology can be obtained and considered as part of the research and clinical examination of children with 22q11.2 DS.

CONCLUSION

The imaging protocol described in this study presents an effective means to counteract difficulties in imaging young children.

Age-Related Changes Between the Level of Velopharyngeal Closure and the Cervical Spine

The primary focus of this study was to assess age-related changes in the vertical distance of the estimated level of velopharyngeal closure in relation to a prominent landmark of the cervical spine: the anterior tubercle of cervical vertebra 1 (C1). Midsagittal anatomic magnetic resonance images were examined across 51 participants with normal head and neck anatomy between 4 and 17 years of age. Results indicate that age is a strong predictor (P = 0.002) of the vertical distance between the level of velopharyngeal closure relative to C1. Specifically, as age increases, the vertical distance between the palatal plane and C1 becomes greater resulting in the level of velopharyngeal closure being located higher above C1 (range 4.88-10.55 mm). Results of this study provide insights into the clinical usefulness of using C1 as a surgical landmark for placement of pharyngoplasties in children with repaired cleft palate and persistent hypernasal speech. Clinical implications and future directions are discussed.

Racial Variations in Velopharyngeal and Craniometric Morphology in Children: An Imaging Study

PURPOSE

The purpose of this study is to examine craniometric and velopharyngeal anatomy among young children (4-8 years of age) with normal anatomy across Black and White racial groups.

METHOD

Thirty-two healthy children (16 White and 16 Black) with normal velopharyngeal anatomy participated and successfully completed the magnetic resonance imaging scans. Measurements included 11 craniofacial and 9 velopharyngeal measures.

RESULTS

Two-way analysis of covariance was used to determine the effects of race and sex on velopharyngeal measures and all craniometric measures except head circumference. Head circumference was included as a covariate to control for overall cranial size. Sex did not have a significant effect on any of the craniometric measures. Significant racial differences were demonstrated for face height. A significant race effect was also observed for mean velar length, velar thickness, and velopharyngeal ratio.

CONCLUSION

The present study provides separate craniofacial and velopharyngeal values for young Black and White children. Data from this study can be used to examine morphological variations with respect to race and sex.

Effects of Gravity on the Velopharyngeal Structures in Children Using Upright Magnetic Resonance Imaging

Objective

The influence of gravity on the velopharyngeal structures in children is unknown. The purpose of this study is to compare the velopharyngeal mechanism in the upright and supine positions while at rest and during sustained speech production in children between 4 and 8 years old.

Methods

A 0.6 Tesla open-type, multipositional magnetic resonance imaging scanner was used to image subjects in the upright and supine positions. The scanning protocol included a T2 fluid attenuation inversion recovery and an oblique coronal turbo spin echo scan with short scanning durations (7.9 seconds) to enable visualization of the velopharyngeal anatomy during rest and production of sustained /i/ and /s/.

Results

The magnetic resonance imaging protocol used for this study enabled successful visualization of the velopharyngeal anatomy in the sagittal and oblique coronal planes at rest and during sustained phonation of /i/ and /s/. Positional differences demonstrated a small nonsignificant ( P > .05) variation for velar measures (length, thickness, and height), retrovelar space, and levator veli palatini measures (length and angles of origin).

Conclusions

Gravity had a negligible effect on velar length, velar thickness, velar height, retrovelar space, levator muscle length, and levator angles of origin. Supine imaging data can be translated to an upright activity such as speech. This is the first study to provide normative levator muscle lengths for children between 4 and 8 years old. Upright imaging may be a promising tool for difficult-to-test populations.

Instrumental assessment of velopharyngeal function and resonance: a review

The purpose of this literature review is to describe and discuss instrumental assessment techniques of the velopharyngeal function in order to diagnose velopharyngeal disorders and resonance characteristics. Both direct and indirect assessment techniques are addressed, in which successively nasopharyngoscopy, videofluoroscopy, magnetic resonance imaging (MRI), cephalometric radiographic analysis, computed tomography (CT), ultrasound, acoustic and aerodynamic measurements are considered. Despite the multiple instrumental assessments available to detect and define velopharyngeal dysfunction, the ideal technique is not yet accessible. Therefore, a combination of different quantitative parameters can possibly form a solution for a more reliable determination of resonance disorders. These multi-dimensional approaches will be described and discussed. The combination of quantitative measurement techniques and perceptual evaluation of nasality will probably remain necessary to provide sufficient information to make appropriate decisions concerning the diagnosis and treatment of resonance disorders.

LEARNING OUTCOMES

The reader will be able to describe and discuss currently available instrumental techniques to assess the velopharyngeal mechanism and its functioning in order to diagnose velopharyngeal disorders. Additionally, he will be able to explain the possible advantages of the combination of several types of complementary measurement techniques.

Anthropometric Analysis of the Velopharynx and Related Craniometric Dimensions in Three Adult Populations Using MRI

OBJECTIVE

The purpose of this study is to examine effects of sex, race, and craniometry among three distinct racial groups of adults with normal velopharyngeal anatomy and to determine whether craniofacial structures could be used to predict velopharyngeal structures.

METHODS

A total of 88 adults across three racial groups including white, black, and Asian (Japanese) participated. Magnetic resonance images were obtained using a high-resolution, three-dimensional anatomical scan. Measurements were obtained on the levator veli palatini muscle, velum, and craniofacial structures.

RESULTS

Head circumference was used as a covariate to control the effect of overall cranial size on the analyses. Palate height, linear cranial base, and face height and width vary based on sex, with men demonstrating larger values compared with women. Linear base values, cranial base angle, and face width vary significantly based on race, with Japanese subjects showing the smallest anterior to posterior measures and larger face-width values. Levator muscle measures, excluding angle measures, vary significantly (P < .0001) based on sex. There was no statistically significant difference (P > .05) among racial groups in the levator muscle measures. Velar length and thickness varied significantly based on race and sex.

CONCLUSIONS

This is the first study to examine the interaction of race and sex on levator muscle morphology. In spite of the differences in velar dimensions, no significant differences were found in muscle size, specifically the levator veli palatini, which is contained within the velum.

Magnetic Resonance Imaging of Velar Muscle Tissue Distribution in Healthy Adults

OBJECTIVES

To examine muscle tissue distribution along the length of the velum in living individuals using magnetic resonance imaging (MRI).

DESIGN

Using the three-dimensional MRI data acquired from 10 normal white adults, two area measures including the muscular area and the total velar area were obtained from 10 oblique slices running perpendicular to velar length. A polynomial regression analysis was performed where the proportion of the muscular to the total velar area was regressed on the slice numbers running along the length of the velum.

RESULTS

The proportion of the muscular to total velar area increased from the anterior section of the velum, reaching a maximum (33.24%) in the midsection, and decreasing in the posterior section of the velum. A third-order (cubic) polynomial function that best illustrated the proportional data (R(2) = .47) was derived.

CONCLUSIONS

The present study demonstrated that MRI is a viable tool to examine the muscle tissue distribution of the velum in living individuals. Although the overall pattern in the muscle tissue distribution of the healthy velum was similar to that reported in previous literature based on cadaver specimens, the participants in the present study appeared to have greater muscular proportion of the velum. The muscular proportion measure derived from the healthy living individuals can be used as an additional parameter accounting for sufficient intravelar muscle mass for future studies.

Sexual dimorphism of the levator veli palatini muscle: an imaging study

Objective : Magnetic resonance imaging studies of the levator veli palatini muscle have used small numbers of subjects and have not consistently controlled for sex, race, or age. The purpose of this study was to conduct a structural assessment using a large homogeneous sample to examine the sex differences in the levator muscle morphology. Methods : Thirty white adult subjects (15 men and 15 women) were imaged using a 3 Tesla MRI system. A high-resolution SPACE (sampling perfection with application-optimized contrasts using different flip-angle evolution) sequence was used to acquire images of the velopharyngeal anatomy. Levator muscle measurements were obtained. Results : Men displayed significantly greater levator extravelar segment length (P = .003), levator intravelar segment muscle length (P < .001), greater distance between levator insertion points (P < .001), and greater angles of origin (P = .008) compared with women. There was no statistically significant variation between men and women in the distance between points of origin at the base of the skull. Conclusions : This study provides normative data to improve understanding of levator dysmorphology such as that in cleft palate muscle anatomy. Results of the study demonstrate significant differences between white men and women across several levator muscle measures. Variations in the relative size of the cranium or height of the individual were not proportionate to the variations observed in the levator muscle.

Using MRI for assessing velopharyngeal structures and function

OBJECTIVE

Direct visualization of the velopharynx and, in particular, the levator muscle is particularly important in the assessment of velopharyngeal function and normal speech production. The purpose of this study is to demonstrate the development of a static and dynamic magnetic resonance imaging protocol for evaluation of velopharyngeal structures and function.

METHODS

A high-resolution, T2-weighted turbo-spin-echo three-dimensional anatomical scan (sampling perfection with application optimized contrasts using different flip angle evolution) was used to acquire a large field of view covering the velopharyngeal anatomy. Dynamic speech assessment was obtained using a fast-gradient echo, fast low-angle shot, multi-shot spiral technique to acquire 15.8 frames per second (FPS) of the sagittal and oblique coronal image planes.

RESULTS

Using a three-dimensional data set, as opposed to two-dimensional data, the full contour of the levator muscle can be appreciated. Dynamic images were obtained at 15.8 FPS in the sagittal and oblique coronal planes, enabling visualization of the movements of the velum, posterior pharyngeal wall, lateral pharyngeal walls, and levator muscle during speech.

CONCLUSIONS

A three-dimensional magnetic resonance imaging sequence, such as that used in the present study, may provide better analyses and more precise measurements. A dynamic fast low-angle shot sequence allows for visualization of the levator muscle and the velum during speech at a high image rate. This protocol could have a significant impact in improving the process of visualizing pathology and promoting clinical treatment plans for individuals born with cleft lip and palate.

Morphology of the levator veli palatini muscle using magnetic resonance imaging

Background : No studies have reported the circumference and diameter of the levator veli palatini muscle at multiple points along its length and from both views (frontal and lateral). The purpose of this study was to provide quantitative data regarding the levator muscle morphology along the length of the muscle using magnetic resonance imaging and advanced three-dimensional computer technology. Methods : Ten Caucasian male subjects participated in the study. Subjects were scanned using a Siemens 3 T Trio. Levator muscle measures were obtained using a two-dimensional image plane. A three-dimensional model was used to measure the circumference and muscle diameter (in two directions) at six points along the length of the levator muscle. Results : Levator muscle length ranged from 41.67 mm to 52.85 mm across all subjects. Mean extravelar muscle length was 30.55 mm (SD, 2.8 mm) and 30.01 mm (SD, 2.9 mm) for right and left muscles. The mean circumference at the origin was 18.90 mm (SD, 2.6 mm). At the second point, the muscle circumference mean increased slightly (mean, 22.40 mm; SD, 4.9 mm). The means for the remainder of the measures (points 3, 4, 5, and 6) were consistent, showing little to no change. Conclusion : Circumference and diameter values were similar to those reported in previous literature. The muscle did diverge at the point where the muscle bundle entered the velum, as it has been previously described. Instead, the muscle diverges near the midline insertion becoming sparser (smaller superior-to-inferior diameter).

Using magnetic resonance imaging for early assessment of submucous cleft palate: a case report

Surgical correction for submucous cleft palate is generally indicated in the presence of velopharyngeal inadequacy. Clinical assessment of velopharyngeal inadequacy requires that the child is able to produce a connected speech sample, which can yield a delay in treatment decisions that extends through a critical period of speech and language development. A perceptual speech assessment and intraoral examination are traditionally the most important methods of establishing a diagnosis of submucous cleft palate. The purpose of this case report is to demonstrate the use of magnetic resonance imaging as a diagnostic tool to provide early identification and an indication of surgical treatment for an individual born with a submucous cleft palate. The magnetic resonance images indicated a discontinuous levator veli palatini muscle sling arrangement with attachment of the muscle bundles onto the hard palate. Surgery was performed at 16 months and postsurgical speech evaluations demonstrated normal resonance and age-appropriate speech.