Dynamic upper airway collapse observed from sleep MRI: BMI-matched severe and mild OSA patients

Abstract

Dynamic magnetic resonance imaging (MRI) allows real-time characterization of upper airway collapse in sleeping subjects with obstructive sleep apnea (OSA). The aim of our study was to use sleep MRI to compare differences in upper airway collapse sites between BMI-matched subjects with mild OSA and severe OSA. This is a prospective, nested case-control study using dynamic sleep MRI to compare 15 severe OSA subjects (AHI >40) and 15 mild OSA (AHI <10) subjects, who were matched for BMI. Upper airway imaging was performed on sleeping subjects in a 3.0 T MRI scanner. Sleep MRI movies were used by blinded reviewers to identify retropalatal (RP), retroglossal (RG), and lateral pharyngeal wall (LPW) airway collapse. Mean AHI in the severe OSA group was 70.3 ± 23 events/h, and in the mild group was 7.8 ± 1 events/h (p < 0.001). All mild and severe OSA subjects demonstrated retropalatal airway collapse. Eighty percent in the mild group showed single-level RP collapse (p < 0.001). All subjects in the severe group showed multi-level collapse: RP + LPW (n = 9), RP + RG + LPW (n = 6). All severe OSA subjects showed LPW collapse, as compared with three subjects in the mild group (p < 0.001). LPW collapse was positively associated with AHI in simple regression analysis (β = 51.8, p < 0.001). In conclusion, severe OSA patients present with more lateral pharyngeal wall collapse as compared to BMI-matched mild OSA patients.

Personalised medicine in sleep respiratory disorders: focus on obstructive sleep apnoea diagnosis and treatment

“…Different approaches have been developed to assess the functional and anatomical impairment of the upper airway in OSA, such as computed tomography (CT), magnetic resonance imaging (MRI), cephalometry, nasopharyngoscopy and drug-induced sleep endoscopy (DISE). The latter two provide information about the airway during static, awake or pharmacologically induced sleep states [41].…”

“…Using sleep endoscopy in suspected OSA patients, BACHAR et al [48] found that the velopharynx was the most common site of obstruction (89% of patients), and most of the patients (72%) had multiple sites of obstruction. HUON et al [41] observed more multilevel and lateral pharyngeal wall collapse in patients with severe OSA compared to body mass index (BMI)-matched mild OSA patients, by using sleep MRI. These data may explain the poor predictive value of single measurements of airway anatomy and the relatively high failure rate of uvulopalatopharyngoplasty (UPPP) surgery [49,50].…”

“…For example, the hypoglossal nucleus, which controls the GGM, receives inputs from premotor pacemaker neurons of the respiratory pattern generator, upper airway negative-pressure receptors, chemoreceptors and stretch receptors. During wakefulness this activity is augmented; at sleep onset the activity of the upper airway dilator muscles is diminished or lost and may underlie the airway collapse [41,58].…”

Comparação histológica entre as fibras dos músculos palatofaríngeo e constritor superior da faringe em indivíduos com e sem apneia obstrutiva do sono

“…De maneira geral, a área seccional da via aérea medida por meio de visualização direta ou de imagens de tomografia computadorizada (TC) e ressonância nuclear magnética (RNM) durante a vigília e durante o sono está reduzida em pacientes com SAOS em comparação a indivíduos saudáveis (Schwab et al, 1995;Huon et al, 2016).…”

“…Dentre os diferentes padrões obstrutivos demonstrados em exames de imagem da faringe e de sonoendoscopia, na maioria dos pacientes, observase a participação do palato mole e/ou parede lateral da faringe (Schwab et al, 1995;Huon et al, 2016). Anatomicamente, a parede lateral da faringe representa o local de inserção do palato mole na faringe.…”