Table 3.

Describes these studies found

Paper	Subjects	Measurement method and software	Outcome	Statistics used	Figures
Fujioka et al 1979. Radiographic evaluation of adenoidal size in children: adenoid nasopharyngeal ratio	1398 infants and children (1 month–16 yrs)	Lateral radiographs. Adenoid (linear measurement from maximal convexity along inferior margin of adenoid shadow to straight part of anterior margin of bassiocciput). Nasopharynx (linear measurement from posterior superior edge of hard palate to anteroinferior edge of sphenobasioccipital synchondrosis. When synchondrosis is not clearly visualised, the site of crossing posteroinferior margin of lateral pterygoid plates and floor of bony nasopharynx)	An adenoidal-nasopharyngeal ratio greater than 0.8 was present in 94% subjectively judged to have enlarged adenoids	Information not available	Figure S152
Arens et al 2001. MRI of upper airway structure of children with OSAS	18 children with OSAS (age 4.8±2.1 yrs); 18 matched	1.5 Tesla Siemens vision system. Axial and sagittal T1- and T2-weighted images with 3-mm slice thickness and 1 NEX. Slices spanning from base of orbital cavities to epiglottis. Axial = T1-weighted image, maximal tonsillar cross-sectional area level, cross section measurements of oropharyngeal airway (anterior border soft palate/tongue, lateral border tonsils, posterior border pharyngeal constrictor muscles), tonsils, pterygoids, parapharyngeal fat pads. Also, linear measurements across transverse line centre of tonsils (intertonsillar width, bilateral tonsillar width, bilateral fat pad width, bilateral pterygoid width, intermandibular distance). Other axial levels – largest adenoid cross section, maxilla width, internal distance between madibular heads. Sagittal = T1-weighted midsagittal, cross-sectional area of nasopharyngeal airway (anterior border vomer, posterior border adenoid, inferior border horizontal line above hard and soft palate), adenoid, soft palate, tongue, mandible, hard palate. Also, linear measurements along oblique line of mental spine, centre soft palate and clivus (ie, tongue oblique, soft palate oblique, airway oblique, adenoid oblique, mental spine-clibus oblique). Length – hard palate (anterior nasal spine to end palatine bone) Volumetric measurements = adjacent axial slices. Combined upper airway (nasopharynx and oropharynx), tongue, soft palate, mandible (T1-weighted), tonsils, adenoid (T2 – better resolution lymphoid tissues)	In OSAS volume of upper airway smaller, adenoids and tonsils larger. Soft palate larger. Volumes of mandible, tongue similar both groups	Two-tailed unpaired t test, Wilcoxon rank test, or chi- square test. The Pearson correlation used to asses linear correlation of volume percent difference of each OSAS-control pair and AHI	Figure S247
Uong 2001. MR imaging of upper airway in children with down syndrome	11 down syndrome children without OSA (age 3.2 yrs±1.4 yrs); 14 controls (age 3.3±1.1 yrs)	1.5-T Siemens vision system. VIDA software. Sequential T1 and T2-weighted spin-echo axial and sagittal. Axial: retropalatal axial T1-weighted image at level of maximal tonsillar cross-sectional area they measured tonsils, pterygoids, parapharyngeal fat pads, airway cross section. Other axial images – largest adenoid area, maximum maxilla width, internal distance between mandibular heads. Sagittal: midsagittal T1-weighted image they measured cross-sectional areas of adenoid, soft palate, tongue, mandible, hard palate, combined nasopharyngeal and oropharyngeal airway. Length of hard palate (nasal spine to end palatine bone). Mandible size (mental spine and the clivus through soft palate centroid). Volumetric measurements – adjacent axial slices. Adenoid, tonsils, (both T2), tongue, soft palate, mandible, total nasal/oral pharyngeal airway (rest T1)	In Down syndrome group found smaller airway volume, mid and lower face skeleton. Shorter mental spine-clivus distance, hard palate length and mandible volume. Adenoid and tonsil volume smaller. Tongue, soft palate, pterygoid, and parapharyngeal fat pads similar to controls	Two-tailed unpaired t test, Wilcoxon rank test, or chi-square test	Figure S373
Arens et al 2002. Linear dimensions of the upper airway structure during development	92 normal children	1.5 Tesla Siemens vision system. Sequential T1-weighted images. VIDA software. Sagittal = midsagittal T1-weighted, lower face sagittal skeletal growth by measuring mental spine-clivus length (distance between mental spine – ie, point of insertion of genioglossus to mandible- and clivus passing through soft palate centroid. Linear measurements – tongue oblique width, soft palate oblique width, nasopharyngeal airway oblique width, adenoid oblique width. Axial = lower face skeletal growth was determined by intermandibular length (between medial aspects of both mandibular rami along transverse line passing through tonsil centroid) at level of maximal tonsillar cross section. Linear measurements incl intertonsillar width, bilateral tonsillar width, bilateral fat pad width, bilateral pterygoid width. Also, oropharngeal width (maxinal oropharngeal width on a line parallel to intermandibular line)	In midsagittal plane, mental spine-clivus distance related linearly to age. Tongue, soft palate, nasopharyngeal airway, adenoid increased with and maintained constant proportion to mental spine-clivus distance. Linear relationship for mandibular growth growth measured along intermanduibular line on axial plane and age. Intertonsillar, tonsils, parapharyngeal fat pads, pterygoids widths maintained constant proportion to intermandibular width with age. Lower face skeleton grows linearly along sagittal and axial planes from 1st to 11th year. Soft tissues, incl tonsils and adenoids, surrounding upper airway grow proportionally to skeletal structures	Linear regression analysis	Figure S4121
Arens et al 2003. Upper airway size analysis by MRI of children with OSAS	20 children with OSAS (age 3.7±1.4);20 controls	1.5 Tesla Siemens vision system. Sequential T2-weighted spin echo axial sections obtained spanning from orbital cavity to larynx. Images transferred to SUN workstation, 3DVIEWNIX softwarre (fuzzy connectedness segmentation). 1. Upper airway centerline = bounded by upper nasopharynx (posterior edge vomer), lower oropharynx (superior part epiglottis). Airway regions adjacent to adenoid, tonsils, overlap measured along centerline. 2. Upper airway cross-sectional area = at planes orthogonal to centreline. Mean and minimal cross section of total airway; mean cross section adjacent to adenoid, tonsils and overlap between the two. 3. Upper airway volume = centerline length and mean cross-sectional area. Volumes for 10 consecutive segments at 10% increments of centerline were computed	In OSAS group mean and minimal cross-sectional area of total airway smaller. Upper airway in OSS is most restricted where adenoid and tonsils overlap	Two-tailed unpaired t test, Wilcoxon rank test, or chi- square test	Figure S548
Schwab et al 2003. Identification of upper airway anatomic risk factors for OSAS with	48 subjects with OSAS; 48 controls	1.5 Tesla (online supp). Volumetric measurements = lateral pharyngeal walls (retropalatal and retroglossal); soft palate; tongue (genioglossus, geniohyoid, hyoglossus, myohyoid, digastric, myohyoideous muscles); parapharyngeal fat pads; total	In OSAS group, volume of lateral pharyngeal walls, tongue, total soft tissues larger. Increased risk of OSAS the larger the volume of the tongue, lateral pharyngeal walls and total soft tissue	Chi-square tests and t tests. Multiple logistic regression models used to obtain adjusted odds ratios and 95% CI for effect opf a 1SD change in size of airway and soft tissue measurement.	Figure S651
Arens et al 2005. Changes in upper airway size during tidal breathing in children with OSAS,	10 OSAS children (age 4.3±2.3 yrs); 10 matched controls.	1.5 Tesla Siemens Sonata system using 2D trueFlSP sequence. VIDA software. Axial images. Respiratory gating performed. Data for 40 mm axial from epiglottis to upper nasopharynx obtained from 10×4 mm slices uring 10 successive breath in todal breathing (Vt) – 10,30,50,70,90% of inspiration and of expiration.	Subjects with OSAS – smaller upper airway cross sectional area; airway narrowing during inspiration but without airway collapse; airway dilatation during expiration; greater fluctuations in airway area during tidal breathing.	Two tailed unpaired t test, wilcoxon rank test, or Chi-square test.	Figure S7125
Schwab et al 2006. Family aggregation of upper airway soft tissue structures in normal subjects and pts with sleep apnea	55 sleep apnea probands; 55 proband siblings	1.5 Tesla MRI scanner spin echo axial and sagittal images. 3D volumes of lateral pharyngeal walls (retropalatal and retroglossal regions); soft palate; tongue (genioglossus, geniohyoid, hyoglossus, myohyoid, digastric, myohyoideus muscles); parapharyngeal fat pads; soft tissue.	Volume of lateral pharyngeal walls, tongue, total soft tissue demonstrated heritability. Upper airway larger in normal subjects. Tongue, lateral parapharyngeal fat pads, lateral parapharyngeal walls larger in patients with apnea	Mixed model analysis of variance ANOVA; odds ratio	Figure S8145
Arens et al 2011. Upper airway structure and body fat composition in obese children with OSAS	22 obese children with OSAS (12.5±2.8 yrs; BMI z score 2.3±0.3); 22 obese controls	16 channel Philips 3.0 Tesla Achieva Quasar TX scanner. Amira software. Volumetric measurements – Upper airway = nasopharynx (superior to soft palate and continues anteriorly, through choanae, with nasal cavities); oropharynx (region between soft palate and larynx, posterior 1/3rd of tongue as anterior border); hypopharynx (posterolateral to larynx, includes pyriform recesses and valleculae). Lymphoid tissue = (adenoid, combined palatine tonsils, combined retropharyngeal nodes – between internal carotid arteries from base skull to hyoid bone – and deep cervical lymph nodes – internal jugular vein from base skull to hyoid bone). Tongue (inc genioglossus and geniohyoid muscles). Soft palate. Mandible. Head/neck = parapharyngeal and subcutaneous fat	Size of lymphoid tissue correlated with OSAS severity but bMl z score did not have modifier effect on lymphoid tissue. OSAS subjects had increased size parapharyngeal fat pads, abdominal visceral fat (did not correlate with OSAS severity)	Two-tailed paired t tests, Wilcoxon signed rank tests or McNemar’s tests. Pearson correlations derived between AHI and BMI z score. Mixed effects regression models using AHI as dependant variable and conditional regression models with OSAS vs non OSAS as dependant variable	Figure S949
Cappabianca et al 2012. Magnetic resonance imaging in the evaluation of anatomical risk factors for pediatric obstructive sleep apnea – hypopnea: a pilot study	80 Caucasian children aged 4– 15 years, of which 40 had been diagnosed with OSAS	Retrospective analysis MRI head and neck between March 20102012. 1.5T magnet Symphony, Siemens. Axial T1-weighted images: cross-sectional area oropharyngeal airway, bounded anteriorly by soft palate or tongue, laterally by tonsils, posteriorly by pharyngeal constrictor muscle; intermandibular distance, maximum distance between the mandibular rami; maxillary width, maximum transverse diameter of superior jaw. Axial T2-weighted images: largest cross-sectional area of adenoids, tonsils, pterygoids, and parapharyngeal fat pads. Midsagittal T1-weighted image: cross-sectional area of nasopharyngeal airway, bounded anteriorly by vomer, posteriorly by adenoid, and inferiorly by horizontal line above the hard and soft palate; the cross sectional area of adenoids, soft palate, tongue, mandible, and hard palate. Other: distances from a transverse line perpendicular to the floor passing through the hyoide (hy, the most cranially – located point of the hyoid bone) to nasion (hy–n), to sella (hy–s) and to supramentale (hy–B) and the angles sella–nasion–subspinale (SNA), sella–nasion–supramentale (SNB) and subspinale–nasion–supramentale (ANB). Adjacent axial slices to determine volumes: combined upper airway (nasopharynx and oropharynx), adenoid, tonsils, tongue, soft palate, and mandible. Volumetric measurements (except tonsils and adenoid) from axial T1-weighted slices from base of orbital cavities to epiglottis. T2-weighted images for adenoid and tonsils due to better resolution of lymphoid tissue. Tonsillar volume = volume of right and left	The total upper airway volume of children with OSAS (1.4±0.7 cm3) was significantly smaller (p<0.001) compared to controls (1.6±1.1 cm3); soft palate volume was significantly larger (p<0.01) in OSAS group (3.9±1.3 cm2) compared to controls (3.1±1.4 cm2); adenoid and tonsils were significantly larger in children with OSAS compared to controls (p<0.01) with mean adenoid volume in children with OSAS 9.1±1.8 cm3 vs 6.3±2.1 cm3 in controls and mean tonsillar volume in OSAS 9.2±1.5 cm3 vs 6.5±1.7 cm3 in controls. Interestingly, similarly to Arens (2001) they also noted a smaller mandibular volume (p<0.05) in the OSAS group (22.2±2.23) compared to control group (25.4±2.4 cm3)	Student’s t test	Figure S10124
Strauss et al 2012. Upper airway lymphoid tissue size in children with sickle cell disease	36 children with SCD (aged 6.9±4.3 yrs); 36 controls	1.5 Tesla Siemens vision system. Axial and sagittal T1- and T-2 weighted images 3 mm slice and 1 NEX, from orbital cavity to larynx. Annonymised, converted to DICOM format. AMIRA software. Airway = nasopharynx (superior to level of soft palate and continuous anteriorly, through choanae, with the nasal cavities); oropharynx (between level of soft palate and larynx, communicating anteriorly with oral cavity, posterior 1/3rd of tongue as anterior border); hypopharynx (posterolateral to larynx, communicating with cavity of larynx through auditus, incl pyriform recessed and valleculae). Lymphoid tissues = adenoid, combined palatine tonsils, combined retropharyngeal nodes – lymph nodes between internal carotid arteries from base of skull to hyoid bone – and combined deep cervical lymph nodes – internal jugular vein from base skull to hyoid bone)	Children with SCD – smaller upper airway with larger adenoid, retropharyngeal nodes, deep cervical nodes. AHI correlated positively with upper airway lymphoid tissues size	Two-tailed unpaired t tests and chi-square test. Pearson correlations between AHI and upper airway lymphoid tissues.	Figure S1150
Nanadalike et al 2012. Adenotensillectomy in obese children with OSAS: MRI findings	27 obese children with OSAS (age 13±2.3 yrs; BMI z score 2.5±0.3)	AMIRA software. Philips 3.0 Tesla Achieva scanner with 16 channel surface array coil. Images annonymised converted to DICOM. Sagittal: airway – nasopharynx (superior boundary is base of skull – basisphenoid and basiocciput; inferior boundary upper soft palate; anterior boundary nasal cavities, choanal orifice, posterior nasal septum; posterior boundary pharyngobasilar fascia, superior pharyngeal constrictors). Oropharynx (superior boundary soft palate; inferior boundary upper epiglottis – vallecula fossa – and root of tongue; anterior boundary oral cavity; posterior and lateral boundary superior and middle pharyngeal constrictors). Lymphoid tissues (adenoid, combined palatine tonsils, lingual tonsil, combined retropharyngeal nodes – located between internal carotid arteriesfrom skull base to hyoid bone – plus deep cervical lymph nodes level II – located internal jugular vein from skull base to hyoidbone). Tongue (inc genioglossus and geniohyoid muscles). Soft palate. Mandible. Head and neck subcutaneous fat	Pts followed up 6.1±3.6 mo after AT. AT improved AHI. AT increased volume of nasopharynx and oropharnyx, reduced tonsils, no effect on adenoid, lingual tonsil, retropharyngeal nodes. Increase volume soft palate and tongue	Wilcoxon signed rank test for paired data	Figure S12146
Parikh et al 2013. Deep cervical lymph node hypertrophy: a new paradigm in the understanding of pediatric obstructive sleep apnea	70 children with OSAS (mean age 7.47 yrs; BMI 23.63 kg/m2) and 76 healthy matched controls (mean 8.00 yrs; BMI 20.87 kg/m2)	1.5 Tesla (Siemens Vision System, Iselin, NJ). Four regions of lymphoid tissue: tonsil, adenoid, retropharyngeal nodes (between internal carotid arteries from the skull base to the hyoid bone), and the upper jugular lymph nodes (along the internal jugular vein from the skull base to the hyoid bone)	Children with OSAS have larger volumes of deep cervical lymph nodes and adenotonsillar tissue than normal controls	Chi-square analysis and Student’s t test were used to compare demographics and lymph node volumes. Fischer’s exact test and chi-square analysis were used to compare sleep data	Figure S13123
Salles et al 2014. Association between morphometric variables and nocturnal desaturation in sickle cell anemia	85 children with SCD (9±4 yrs; BMI z score −0.4 in apneic group and −1.0 in non-apneic group)	An oral cavity assessment in the Frankfort position with tongue in relaxed position and with a mouth opening angle of 20°C to the mandibular condyle. A 20°C fixed-aperture compass was used, which was placed on the topography of the temporomandibular joint, the tip of its upper leg aligned with the upper central incisors, to yield desired mouth opening. Another compass was used to obtain measuremnts of: maxillary intermolar distance (size of maxilla); and mandibular intermolar distance (mandibular size) which were then transposed to a ruler. The overjet, cervical circumference and abdominal circumference were measured with a ruler/tape	A positive correlation was found between height/age z-score and cervical circumference. Nocturnal desaturation was associated with cervical circumference and abdominal circumference. A negative correlation between desaturation and maxillary intermolar distance and mandibular intermolar distance	Student’s t test for independent samples or the Mann–Whitney test to compare two means. Spearman’s test to test the correlation between variable.	No imaging available as measurements taken via clinical method116
Schwab et al 2015. Understanding the Anatomic Basis for Obstructive Sleep Apnea Syndrome in Adolescents	Adolescents 12–16 years from CHOP study. 49 obese with OSA; 38 obese and 50 lean controls	Upper airway MRI was performed using a 3T scanner (Magnetom Sonata; Siemens). Amira 4.1.2 image analysis software. Saggital: airway volume, cross-sectional area, minimum airway area in the retropalatal (RP),retroglossal (RG), and nasopharyngeal (NP) regions;minimum anteroposterior airway width, minimum lateral airway width in the RP and RG regions. Airway length: distance between palatal plane and parallel plane through base of epiglottis. Volumetric analysis of upper airway soft tissue structures on axial T1-weighted MRI scans: soft palate, tongue genioglossus muscle, other tongue (geniohyoid, hyoglossus, myohyoid, digastric, and mylohyoid) muscles, parapharyngeal fat pads, lateral pharyngeal walls (including tonsils), pterygoid muscle, epiglottis, sum of soft tissue volumes. Axial T2-weighted for tonsils (right and left combined) and adenoid as better resolution of lymphoid tissue	Obese with OSAS had increased adenotonsillar tissue and smaller nasopharyngeal airway compared with all controls. The size of other upper airway soft tissue structures (volume of the tongue, parapharyngeal fat pads, lateral walls, and soft palate) was similar between both groups	Adjusted analysis of covariance was used to compare the three groups with a subdomain-specific, Bonferroni-corrected level of significance	Figure S14147
Tong et al 2016. MR Image Analytics to Characterize the Upper Airway Structure in Obese Children with Obstructive Sleep Apnea Syndrome	30 children 8–17 yrs (15 obese with OSAS; 15 obese controls)	Philips Achieva 3T machine. Axial T2-weighted and sagittal T1-and T2-weighted sequences. “Object” measurements: skin, pharnyx, nasopharynx, oropharynx, mandible, fat pad, adenoid, tonsils, tongue, soft palate. 3D region enclosed by the boundary surface was considered to represent the “object.	OSAS group: increase in linear size, surface area, volume of adenoid, tonsils, fat pad. Fat pad and oropharynx become less round/more complex in shape in OSAS	. Logistic regression based on a sigmoid model	Figure S15148