Using MRI for Assessing Velopharyngeal Structures and Function

Abstract

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.

A Computational Model of Velopharyngeal Closure for Simulating Cleft Palate Repair

“…The LVP of infants is approximately two-thirds of the length of the LVP of adults. 13,20,24,25 This suggests that scaling down the simulated overlap distances for surgeries on infants and children would produce the same mechanical effects on closure force. Estimated overlap amounts for adults and infants based on the overlap percentages from this study are shown in Table 2.…”

“…Models can integrate the wealth of literature describing the anatomy, physical properties, and in vivo function of the VP mechanism [15][16][17][18][19][20][21][22][23][24][25] and then be used to systematically investigate cause-and-effect relationships that would be either impossible to accomplish in vivo or take decades of clinical trials to uncover. For example, models have the ability to quantify the effect of varying surgical parameters, like the extent of LVP overlap.…”

Influência da amostra de fala no julgamento perceptivo da hipernasalidade

“…Portanto, durante a fala, as estruturas velofaríngeas estão em atividade, realizando movimentos constantes de abertura e fechamento da válvula velofaríngea de acordo com o tipo de som, oral ou nasal, que é produzido (KUMMER, 2001;KUEHN, 2007;KUMMER, 2014;PERRY et al, 2014).…”

“…Sabe-se que, apesar de todos os esforços para se estabelecer a função velofaríngea adequada por meio da palatoplastia primária, uma parcela considerável de indivíduos com fissura palatina permanece com insuficiência velofaríngea (IVF) mesmo após este procedimento cirúrgico (HIRSCHBERG, 1986;GONZÁLEZ LANDA et al, 2000;KUMMER, 2001;NAKAMURA et al, 2003;KUEHN, 2009;PERRY et al, 2014).…”

“…Avaliar a função velofaríngea é um processo difícil devido à sua natureza complexa e dinâmica (PERRY et al, 2014). Por isso, muitos autores têm proposto diferentes formas para categorizar a fala de indivíduos com fissura palatina na tentativa de se estabelecer um padrão universal que possibilite, inclusive, estudos inter-centros (JOHN et al, 2006;HENNINGSSON et al, 2008;LOHMANDER et al, 2009;PRATHANEE et al, 2012;BRITTON et al, 2014).…”