The Influence of Orthodontic Appliances on Magnetic Resonance Imaging of the Velopharynx

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Eshan Schleif (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Magnetic resonance imaging (MRI) is becoming increasingly valuable among cleft palate craniofacial teams in patients with velopharyngeal insufficiency (VPI). One hindrance to the growing use of MRI among the cleft population is the presence of orthodontic appliances, which could result in image distortions and non-interpretability of MR images. This is particularly a challenge because individuals with cleft anatomy have a higher incidence of dental anomalies compared to the non-cleft population (Bohn, 1963\; Jordan et al., 1966\; Schroeder & Green, 1975). Dental anomalies are present in approximately 62% of patients with isolated cleft lip and 96.7% of patients with both cleft lip and palate (Vallino et al., 2008\; Akcam et al., 2010). Previous MRI studies of the brain revealed that some appliances and dental materials cause image distortions which result in non-interpretability of MR images, while others do not interfere with visibility of desired structures (Fiala et al., 1994\; Shafiei et al., 2003\; Hubalkova et al., 2002\; Beau, Bossard, & Gebeile-Chauty, 2015). Currently, it is not known which orthodontic appliances and materials hinder visualization of the velopharyngeal structures during an MRI. The purpose of this study is to evaluate the influence of common pediatric orthodontic appliances on VP MRI. Insights from this study will be useful in determining which patients undergoing orthodontic treatment are candidates for VP MRI. \n\nThis study included nineteen participants undergoing orthodontic treatment. All participants were scanned in a 1.5-Tesla Siemens MRI machine in supine position, capturing 3D and 2D images at rest and during sustained phonation. Two of the commonly used MR sequences for the evaluation of the VP were compared. Two raters experienced in performing MRI evaluations of the velopharynx examined the MRI for distortion in 8 anatomical sites of interest. \n\nThe results of this study demonstrate that some appliances such as hyrax palatal expanders and braces with stainless steel brackets are recommended for a VP MRI, while class II corrector springs are not recommended. The HASTE MRI sequence with 2D imaging techniques should be utilized, while FSE and 3D imaging techniques are not recommended. VP MRI of participants with orthodontic appliances is recommended for clinical cases when information about the LVP muscle length, LVP origin distance, and/or distance from velar knee to posterior pharyngeal wall needs to be obtained. Other forms of imaging, such as lateral cephalogram, should be utilized for this population to determine hard palate length, velar length, pharyngeal depth, and effective velar length. The presence of wire spring coils and molar bands are likely to not to interfere with the MRI evaluation. \n\nFindings from this study suggest that the presence of orthodontic appliances does not hinder visualization of all velopharyngeal structures during an MRI. Therefore, careful consideration must be made prior to disqualifying or recommending patients for VP MRI. The results of this study will be useful in determining which patients undergoing orthodontic treatment are candidates for VP MRI.

Additional Information

Publication

Dissertation

Language: English

Date: 2023

Subjects

Magnetic resonance imaging, velopharyngeal function, speech, orthodontics, levator veli palatini, maxillary advancement

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