Obstructive Sleep Apnea in Pediatric Patients: Evaluation with Cine MR Sleep Studies

Polysomnographic outcomes of revision adenoidectomy in children with obstructive sleep apnea and recurrent/residual adenoidal hypertrophy

INTRODUCTION

Recurrent/residual adenoidal hypertrophy after adenotonsillectomy in children can result in obstructive sleep apnea (OSA). We aimed to assess the polysomnographic (PSG) outcomes of revision adenoidectomy in children with recurrent/residual adenoidal hypertrophy and OSA.

METHODS

This was a single-center retrospective study that included children with sleep studies that confirmed OSA and known history of adenotonsillectomy who were diagnosed with adenoidal hypertrophy and subsequently underwent revision adenoidectomy. Pre- and postoperative PSG variables of revision adenoidectomy were included in the analysis.

RESULTS

A total of 20 children were included in the study. The cohort included 13 males and 7 females with a mean age of 7.8 years (± 3.6 years). The mean BMI z score was 1.96 [1.31, 2.43]. The median duration from adenotonsillectomy performance was 2.3 years [1.4, 4.0]. Overall, revision adenoidectomy resulted in significant improvements in multiple respiratory parameters, including AHI 6.6 [1.4, 13. 7] vs 14.8 [7.4, 20.7], p = 0.02; oxygen desaturations nadir 88.0 [84.0, 93.0] vs 80.0 [72.2, 88.9], p = 0.01; supine AHI 8.6 [1.5, 14.3] vs 17.6 [8.3, 30.2], p = 0.02; and arousal index 12.2 [9.6, 15.7] vs 18.9 [13.4, 24.9], p = 0.04.

CONCLUSIONS

Children with recurrent/residual adenoidal hypertrophy after adenotonsillectomy who undergo revision adenoidectomy experience improvements in respiratory event, gas exchange, and arousal index.

Can Velopharyngeal MRI be Used in Individuals with Orthodontic Devices?

OBJECTIVE

To evaluate the influence of common pediatric orthodontic appliances on velopharyngeal (VP) MRI and to compare MR image sequences to determine if sequence parameters impact the visibility of key VP structures commonly assessed in clinical VP MRI.

DESIGN

Participants undergoing orthodontic treatment completed a VP MRI study. Level of distortion caused by orthodontic devices on 8 anatomical sites of interest and using variable MRI sequences was evaluated.

SETTING

Single institution.

PARTICIPANTS

Nineteen participants undergoing orthodontic treatment.

MAIN OUTCOME

Level of distortion caused by metal artifacts and MR sequence used.

RESULTS

The results of this study demonstrate that appliances such as hyrax palatal expanders and braces with stainless steel brackets are acceptable for a VP MRI, while class II corrector springs are not recommended. The HASTE MRI sequence with 2D imaging techniques should be utilized if the child has orthodontic devices, while FSE and 3D imaging techniques are not recommended. The presence of wire spring coils and molar bands are likely to not to interfere with the MRI evaluation.

CONCLUSIONS

Findings 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.

Role of neck radiography in assessing recurrent/residual adenoid hypertrophy in children with OSA and history of adenotonsillectomy: a sleep physician perspective

STUDY OBJECTIVES

Recurrent/residual adenoid hypertrophy after adenotonsillectomy in children can result in obstructive sleep apnea (OSA). We aimed to assess the role of soft tissue neck X-ray (STN-XR) in evaluating recurrent/residual adenoid tissue hypertrophy.

METHODS

This was a single-center retrospective study that included children with sleep study-confirmed OSA and a known history of adenotonsillectomy who underwent STN-XR to evaluate for recurrent/residual adenoid tissue hypertrophy. STN-XR nasopharyngeal obliteration and baseline polysomnographic data were analyzed. Multiple linear regression was used to assess the independent relationship between the results of STN-XR and the total apnea-hypopnea index, while controlling for relevant characteristics.

RESULTS

The study included 160 participants with a median age of 10 years (quartile [Q] 1 = 7, Q3 = 12.25). More than half of the children were male (59.4%) and the median body mass index z-score was 2.11 (Q1 = 1.23, Q3 = 2.54). STN-XR was normal in 39.4%, and it showed mild, moderate, and complete nasopharyngeal obliteration in 20.6%, 32.5%, and 7.5% of the participants, respectively. Multiple regression analysis showed that moderate and complete nasopharyngeal obliteration was associated with an increase in the mean total apnea-hypopnea index by 109% (P = .0002) and 185% (P = .001), respectively, when compared with children without nasopharyngeal obliteration. However, mild nasopharyngeal obliteration, body mass index z-score, age, sex, and race were not significantly associated with an increase in the total apnea-hypopnea index.

CONCLUSIONS

STN-XR was useful in assessing recurrent/residual adenoid tissue hypertrophy in children with OSA and a history of adenotonsillectomy. Moderate and complete nasopharyngeal obliteration were associated with significantly increased apnea-hypopnea index. Pediatric sleep physicians may consider STN-XR in the evaluation of children with OSA and previous history of adenotonsillectomy.

CITATION

Senthilvel E, Nguyen QL, Gunaratnam B, Feygin YB, Palani R, El-Kersh K. Role of neck radiography in assessing recurrent/residual adenoid hypertrophy in children with OSA and history of adenotonsillectomy: a sleep physician perspective. J Clin Sleep Med. 2023;19(6):1027-1033.

A novel method to generate dynamic boundary conditions for airway CFD by mapping upper airway movement with non-rigid registration of dynamic and static MRI

Computational fluid dynamics (CFD) simulations of airflow in the human airways have the potential to provide a great deal of information that can aid clinicians in case management and surgical decision making, such as airway resistance, energy expenditure, airflow distribution, heat and moisture transfer, and particle deposition, as well as the change in each of these due to surgical interventions. However, the clinical relevance of CFD simulations has been limited to date, as previous models either did not incorporate neuromuscular motion or any motion at all. Many common airway pathologies, such as obstructive sleep apnea (OSA) and tracheomalacia, involve large movements of the structures surrounding the airway, such as the tongue and soft palate. Airway wall motion may be due to many factors including neuromuscular motion, internal aerodynamic forces, and external forces such as gravity. Therefore, to realistically model these airway diseases, a method is required to derive the airway wall motion, whatever the cause, and apply it as a boundary condition to CFD simulations. This paper presents and validates a novel method of capturing in vivo motion of airway walls from magnetic resonance images with high spatiotemporal resolution, through a novel combination of non-rigid image, surface, and surface-normal-vector registration. Coupled with image-synchronous pneumotachography, this technique provides the necessary boundary conditions for dynamic CFD simulations of breathing, allowing the effect of the airway's complex motion to be calculated for the first time, in both normal subjects and those with conditions such as OSA.

Magnetic resonance imaging of obstructive sleep apnea in children

Sleep-disordered breathing has a spectrum of severity that spans from snoring and partial airway collapse with increased upper airway resistance, to complete upper airway obstruction with obstructive sleep apnea during sleeping. While snoring occurs in up to 20% of children, obstructive sleep apnea affects approximately 1-5% of children. The obstruction that occurs in obstructive sleep apnea is the result of the airway collapsing during sleep, which causes arousal and impairs restful sleep. Adenotonsillectomy is the first-line treatment of obstructive sleep apnea and is usually effective in otherwise healthy nonsyndromic children. However, there are subgroups in which this surgery is less effective. These subgroups include children with obesity, severe obstructive sleep apnea preoperatively, Down syndrome, craniofacial anomalies and polycystic ovarian disease. Continuous positive airway pressure (CPAP) is the first-line therapy for persistent obstructive sleep apnea despite previous adenotonsillectomy, but it is often poorly tolerated by children. When CPAP is not tolerated or preferred by the family, surgical options beyond adenotonsillectomy are discussed with the parent and child. Dynamic MRI of the airway provides a means to identify and localize the site or sites of obstruction for these children. In this review the authors address clinical indications for imaging, ideal team members to involve in an effective multidisciplinary program, basic anesthesia requirements, MRI protocol techniques and interpretation of the findings on MRI that help guide surgery.

Characterization of upper airway obstruction using cine MRI in children with residual obstructive sleep apnea after adenotonsillectomy

OBJECTIVES/BACKGROUND

Tonsillectomy and adenoidectomy (T&A) lead to resolution of obstructive sleep apnea (OSA) in most children. However, OSA persists in about 25-40% of children. Cinematic magnetic resonance imaging (cine MRI) can aid the management of persistent OSA by localizing airway obstruction. We describe our experience in implementing and optimizing a cine MRI protocol by using a 3 Tesla MRI scanner, and the use of dexmedetomidine for sedation to improve reproducibility, safety, and diagnostic accuracy.

PATIENTS/METHODS

Patients aged 3-18 years who underwent cine MRI for the evaluation of persistent OSA after T&A and failed positive airway pressure (PAP) therapy were included. Clinical data and the apnea-hyponea index were compared with quantitative and qualitative estimates of airway obstruction from imaging sequences.

RESULTS

A total of 36 children were included with a mean age of 9.6 ± 4.6 (SD) years with 40% over 12 years of age. Two-thirds of them were boys. Seventeen out of 36 children (47%) had Down syndrome. Single site and multilevel obstruction were identified in 21 of 36 patients (58%) and in 12 of 36 patients (33%), respectively. All cine MRIs were performed without complications. Multiple regression analysis demonstrated that a combination of the minimum airway diameter and body mass index z-score best predicted OSA severity (P = 0.002).

CONCLUSIONS

Cine MRI is a sensitive, safe, and noninvasive modality for visualizing upper airway obstruction in children with persistent OSA after T&A. Accurate identification of obstruction can assist in surgical planning in children who fail PAP therapy.

Upper Airway Reflexes are Preserved During Dexmedetomidine Sedation in Children With Down Syndrome and Obstructive Sleep Apnea

STUDY OBJECTIVES

The assessment of pharyngeal collapsibility is difficult to perform in children under normal sleep. An alternative is to perform the assessment under an anesthetic, such as dexmedetomidine (DEX), that induces non-rapid eye movement (NREM) sleep. The objectives of this study were to compare critical closing airway pressure (Pcrit) obtained during natural sleep to that obtained under DEX in patients with Down syndrome (DS) and persistent obstructive sleep apnea (OSA) and determine whether Pcrit measured under sedation predicts the severity of OSA.

METHODS

The passive and active Pcrit, which represent airway passive mechanical properties and active dynamic responses to airway obstruction, respectively, were measured. Upper airway reflex activity was estimated by calculating the difference between active and passive Pcrit. Subjects underwent overnight polysomnography during which Pcrit was measured during normal sleep. Pcrit was also measured during DEX sedation at a dose of 2 μg/kg/h.

RESULTS

The study included 50 patients with median age of 11.4 years (interquartile range: 7.0-13.9) and median body mass index of 23.0 kg/m² (interquartile range: 18.4-29.1), 66% male and 80% Caucasian. Passive Pcrit was significantly higher than active Pcrit when measured during normal sleep and DEX-induced sleep. There was a positive association between apnea-hypopnea index and passive Pcrit (Spearman r = 0.53, P = .0001) and active Pcrit (r = 0.55, P = .0002) under DEX-induced sleep. There were no significant differences between the Pcrit measurements during natural sleep and during DEX sedation.

CONCLUSION

Patients with OSA can compensate for airway obstruction under DEX-induced sleep. The close association between Pcrit and apnea-hypopnea index suggests that airway responses with DEX sedation parallel those seen during natural sleep.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01902407.

Adenotonsillectomy to treat obstructive sleep apnea: Is it enough?

Although adenotonsillectomy is the first line treatment for children with obstructive sleep apnea syndrome (0SAS),¹ improvement in objectively documented outcomes is often inadequate and a substantial number of children have residual disease. Early recognition and treatment of children with persistent OSAS is required to prevent long-term morbidity. The management of these children is frequently complex and a multidisciplinary approach is required as most of them have additional risk factors for OSAS and comorbidities. In this paper, we first provide an overview of children at risk for persistent disease following adenotonsillectomy. Thereafter, we discuss different diagnostic modalities to evaluate the sites of persistent upper airway obstruction and the currently available treatment options. Pediatr Pulmonol. 2017;52:699-709. © 2016 Wiley Periodicals, Inc.

Ultrasonographic assessment of tonsillar volume in children

OBJECTIVES

Adenotonsillar hypertrophy in children is the most common anatomical abnormality associated with obstructive sleep apnoea. Perioperative complications associated with adenotonsillectomy are more common in children with severe obstructive sleep apnoea. An objective preoperative method to determine the size of tonsils is missing. This study assessed the validity of ultrasound as a tool for measuring tonsillar size in children.

METHODS

Single-institution prospective study of twenty-six children aged 2-6 years who underwent elective bilateral tonsillectomy. Trans-cervical ultrasonographic assessment of tonsillar size prior to tonsillectomy operation was performed. We assessed correlation of ultrasonographic and actual tonsillar volume.

RESULTS

A total of 52 tonsils from 26 patients were measured. Actual and ultrasonographic mean tonsillar volume (±SD) was 3.9 (±2.1) ml and 3.6 (±2.5) ml, respectively (P = 0.24). Ultrasonographic and actual measurements correlated well (r = 0.89).

CONCLUSIONS

This is the first study to show that ultrasound is a suitable objective method for determining tonsillar volume in paediatric patients. Preoperative ultrasound assessment of tonsillar anatomy and size may be an additional and suitable, objective method in the development of a risk stratification system in children with obstructive sleep apnoea undergoing tonsillar surgery.

Dynamic Volume Computed Tomography Imaging of the Upper Airway in Obstructive Sleep Apnea

STUDY OBJECTIVES

To describe a dynamic three-dimensional (3D) computed tomography (CT) technique for the upper airway and compare the required radiation dose to that used for common clinical studies of a similar anatomical area, such as for subjects undergoing routine clinical facial CT.

METHODS

Dynamic upper-airway CT was performed on eight subjects with persistent obstructive sleep apnea, four of whom were undergoing magnetic resonance imaging and an additional four subjects who had a contraindication to magnetic resonance imaging. This Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board, and informed consent was obtained. The control subjects (n = 41) for comparison of radiation dose were obtained from a retrospective review of the clinical picture-archiving computer system to identify 10 age-matched patients per age-based control group undergoing facial CT.

RESULTS

Dynamic 3D CT can be performed with an effective radiation dose of less than 0.38 mSv, a dose that is less than or comparable to that used for clinical facial CT. The resulting data- set is a uniquely complete, dynamic 3D volume of the upper airway through a full respiratory cycle that can be processed for clinical and modeling analyses.

CONCLUSIONS

A dynamic 3D CT technique of the upper airway is described that can be performed with a clinically reasonable radiation dose and sets a benchmark for future use.

Evaluation of upper airway collapsibility using real-time MRI

PURPOSE

To develop and demonstrate a real-time MRI method for assessing upper airway collapsibility in sleep apnea.

MATERIALS AND METHODS

Data were acquired on a clinical 3 Tesla scanner using a radial CAIPIRIHNA sequence with modified golden angle view ordering and reconstructed using parallel imaging and compressed sensing with temporal finite difference sparsity constraint. Segmented airway areas together with synchronized facemask pressure were used to calculate airway compliance and projected closing pressure, Pclose , at four axial locations along the upper airway. This technique was demonstrated in five adolescent obstructive sleep apnea (OSA) patients, three adult OSA patients and four healthy volunteers. Heart rate, oxygen saturation, facemask pressure, and abdominal/chest movements were monitored in real-time during the experiments to determine sleep/wakefulness.

RESULTS

Student's t-tests showed that both compliance and Pclose were significantly different between healthy controls and OSA patients (P < 0.001). The results also suggested that a narrower airway site does not always correspond to higher collapsibility.

CONCLUSION

With the proposed methods, both compliance and Pclose can be calculated and used to quantify airway collapsibility in OSA with an awake scan of 30 min total scan room time. J. Magn. Reson. Imaging 2016;44:158-167.

MRI sleep studies: use of positive airway pressure support in patients with severe obstructive sleep apnea

Maintaining the patency of the upper airway during MRI sleep studies, without an artificial airway placement in sedated or anesthetized patients with severe obstructive sleep apnea (OSA) is a major challenge. We report two cases in which a continuous positive airway pressure (CPAP) was used instead of artificial airway to allow interpretation of the dynamic component of the study.

Radiological findings in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterized by recurrent upper airway obstruction occurring at the level of the pharynx during sleep. Although cephalometric analysis is an important method in the diagnosis of craniofacial deformities, CT and magnetic resonance imaging have been highlighted as the major imaging methods to investigate the possible causes of OSA, which, in most cases, is multifactorial. Magnetic resonance and CT both allow an excellent evaluation of the various anatomical planes of the site of obstruction, which enables better clinical assessment and surgical approach. This pictorial essay aims to describe the aspects that must be evaluated in the diagnostic imaging of patients presenting with the major predisposing factors for OSA.

Real-time 3D magnetic resonance imaging of the pharyngeal airway in sleep apnea

PURPOSE

To investigate the feasibility of real-time 3D magnetic resonance imaging (MRI) with simultaneous recording of physiological signals for identifying sites of airway obstruction during natural sleep in pediatric patients with sleep-disordered breathing.

METHODS

Experiments were performed using a three-dimensional Fourier transformation (3DFT) gradient echo sequence with prospective undersampling based on golden-angle radial spokes, and L1-norm regularized iterative self-consistent parallel imaging (L1-SPIRiT) reconstruction. This technique was demonstrated in three healthy adult volunteers and five pediatric patients with sleep-disordered breathing. External airway occlusion was used to induce partial collapse of the upper airway on inspiration and test the effectiveness of the proposed imaging method. Apneic events were identified using information available from synchronized recording of mask pressure and respiratory effort.

RESULTS

Acceptable image quality was obtained in seven of eight subjects. Temporary airway collapse induced via inspiratory loading was successfully imaged in all three volunteers, with average airway volume reductions of 63.3%, 52.5%, and 33.7%. Central apneic events and associated airway narrowing/closure were identified in two pediatric patients. During central apneic events, airway obstruction was observed in the retropalatal region in one pediatric patient.

CONCLUSION

Real-time 3D MRI of the pharyngeal airway with synchronized recording of physiological signals is feasible and may provide valuable information about the sites and nature of airway narrowing/collapse during natural sleep.

Deep cervical lymph node hypertrophy: a new paradigm in the understanding of pediatric obstructive sleep apnea

OBJECTIVES/HYPOTHESIS

To determine if adenotonsillar hypertrophy is an isolated factor in pediatric obstructive sleep apnea (OSA), or if it is part of larger spectrum of cervical lymphoid hypertrophy.

STUDY DESIGN

Prospective case control study.

METHODS

A total of 70 screened patients (mean age 7.47 years) underwent polysomnography to confirm OSA, and then underwent MRI of the upper airway. Seventy-six matched controls (mean age 8.00 years) who already had an MRI underwent polysomnography. Volumetric analysis of lymphoid tissue volumes was carried out. Chi-square analysis and Student's t test were used to compare demographic data and lymph node volumes between cohorts. Fisher's Exact test and Chi-square analysis were used to compare sleep data.

RESULTS

Patients and controls demonstrated no significant difference in mean age (7.47 vs. 8.00 yrs), weight (44.87 vs. 38.71 kg), height (124.68 vs. 127.65 cm), or body-mass index (23.63 vs. 20.87 kg/m(2)). OSA patients demonstrated poorer sleep measures than controls (P < 0.05) in all polysomnography categories (sleep efficiency, apnea index, apnea-hypopnea index, baseline SpO2, SpO2 nadir, baseline ETCO2, peak ETCO2 , and arousal awakening index). Children with OSA had higher lymphoid tissue volumes than controls in the retropharyngeal region (3316 vs. 2403 mm(3), P < 0.001), upper jugular region (22202 vs. 16819 mm(3), P < 0.005), and adenotonsillar region (18994 vs. 12675 mm(3), P < 0.0001).

CONCLUSIONS

Children with OSA have larger volumes of deep cervical lymph nodes and adenotonsillar tissue than controls. This finding suggests a new paradigm in the understanding of pediatric OSA, and has ramifications for future research and clinical care.

Novel retrospective, respiratory-gating method enables 3D, high resolution, dynamic imaging of the upper airway during tidal breathing

PURPOSE

A retrospective, respiratory-gated technique for measuring dynamic changes in the upper airway over the respiratory cycle was developed, with the ultimate goal of constructing anatomically and functionally accurate upper airway models in obstructive sleep apnea patients.

METHODS

Three-dimensional cine, retrospective respiratory-gated, gradient echo imaging was performed in six adolescents being evaluated for polycystic ovary syndrome, a disorder with a high obstructive sleep apnea prevalence. A novel retrospective gating scheme, synchronized to flow from a nasal cannula, limited image acquisition to predefined physiological ranges. Images were evaluated with respect to contrast, airway signal leakage, and demonstration of dynamic airway area changes.

RESULTS

Two patients were diagnosed with obstructive sleep apnea. Motion artifacts were absent in all image sets. Scan efficiency ranged from 48 to 88%. Soft tissue-to-airway contrast-to-noise ratio varied from 6.1 to 9.6. Airway signal leakage varied between 10 and 17% of soft tissue signal. Automated segmentation allowed calculation of airway area changes over the respiratory cycle. In one severe apnea patient, the technique allowed demonstration of asynchronous airway expansion and contraction above and below a severe constriction.

CONCLUSIONS

Retrospective, respiratory gated imaging of the upper airway has been demonstrated, utilizing a gating algorithm to ensure acquisition over specified ranges of respiratory rate and tidal volume.

Evaluation and management of pediatric obstructive sleep apnea beyond tonsillectomy and adenoidectomy

PURPOSE OF REVIEW

There is an increasing percentage of children with persistent obstructive sleep apnea (OSA) after removal of the tonsils and adenoids (T&A). Although sleep apnea has been an active area of research and treatment in the adult population, our awareness of this problem in children is still in its initial stages. In addition, therapies to successfully treat this residual OSA are still not fully established. It is important to develop evaluation and management protocols for these children.

RECENT FINDINGS

This review will discuss risk factors associated with persistent OSA after T&A and techniques to evaluate the pediatric airway in order to identify the site, or sites, of obstruction. Various medical and surgical options are presented.

SUMMARY

Clinicians need to be aware of the potential for persistent sleep disordered breathing and OSA in children, despite previous T&A. Evaluation protocols and techniques will differ in children, due to limitations in their cooperation during the physical examination. Alternative methods, such as airway endoscopy and cine MRI, are presented. Medical and surgical options are presented. Outcomes data for pediatric populations are rare. Multilevel, single stage surgery has a higher risk for oropharyngeal stenosis in children compared with adults and conservative, multistage approaches may be more appropriate.

Treatment of childhood obstructive sleep apnea

OPINION STATEMENT

An array of surgical, medical and orthodontic treatments is available for treating childhood obstructive sleep apnea. Adenotonsillectomy remains the first choice in treatment, with a need for subsequent clinical and polysomnographic reassessment in selected cases to determine residual sleep-disordered breathing. Residual obstructive sleep apnea is more likely in patients with craniofacial abnormalities or obesity. It may require the use of a positive airway pressure breathing device. Topical corticosteroids, leukotriene antagonists, weight reduction, and positional therapy also play a role in ameliorating childhood obstructive sleep apnea. The published evidence for the efficacy of various treatment modalities consists largely of case-controlled studies and case reports.

Relative rather than absolute macroglossia in patients with Down syndrome: implications for treatment of obstructive sleep apnea

BACKGROUND

Children with Down syndrome are described as having macroglossia as well as midface hypoplasia. We reviewed anatomic parameters on MRI to determine whether adolescents with Down syndrome have true macroglossia or relatively large tongues compared to the small size of their oral cavity. This has implications for the treatment of obstructive sleep apnea, which occurs at a relatively high rate among patients with Down syndrome.

OBJECTIVE

To determine whether adolescents with Down syndrome have relative rather than true macroglossia.

MATERIALS AND METHODS

On sagittal and axial MR images, parameters for tongue size (area in sagittal midline), the bony craniofacial confines of the retroglossal pharynx (distance between the mandibular rami and distance between the posterior aspect of the mental mandible and the anterior aspect of the spine), and the size of the tongue relative to the craniofacial bony parameters [tongue area/(transverse diameter x anterior-to-posterior diameter)] were compared between 16 patients with Down syndrome and 16 age- and gender-matched controls.

RESULTS

The tongue area was significantly smaller in patients with Down syndrome (2,432 mm2) than in the control patients (2,767 mm2; P=0.02). The craniofacial bony parameters were also smaller in patients with Down syndrome than in the controls (left-right 69.8 vs. 80.1 mm, P<0.001; anterior-posterior 64.2 vs. 74.9 mm, P<0.001). However, the size of the tongue relative to the craniofacial parameters was larger in the patients with Down syndrome (0.54) than in the controls (0.46; P<0.001).

CONCLUSION

Children with Down syndrome do not have true macroglossia but have relatively large tongues compared to the bony confines of the oral cavity.

Evaluation of the upper airway in children

PURPOSE OF REVIEW

To summarize the current state of the art in upper-airway evaluation, focusing on endoscopic techniques, and especially to make a comparison between rigid and flexible instrumentation.

RECENT FINDINGS

'Noninvasive' techniques such as computed tomography or magnetic resonance imaging (especially cine-magnetic resonance imaging) can yield useful information, but endoscopy remains the gold standard. There is increasing understanding of the limitations and special advantages of rigid and flexible techniques for airway endoscopy; neither yields the entire picture in every patient.

SUMMARY

The combination of both rigid and flexible endoscopic techniques, together with a carefully orchestrated approach to sedation/anesthesia, will yield the most accurate, complete, and useful information.

The frequency of lingual tonsil enlargement in obese children

OBJECTIVE

Enlargement of the lingual tonsils is being increasingly recognized as a not uncommon and treatable cause of obstructive sleep apnea, particularly in patients with Down syndrome who have undergone palatine tonsillectomy and adenoidectomy. We have recognized an increasing number of patients who are obese and have obstructive sleep apnea with enlarged lingual tonsils. The purpose of this study was to evaluate the frequency of enlarged lingual tonsils in obese children.

SUBJECTS AND METHODS

Seventy-one obese children (mean body mass index = 41.6 kg/m(2)) underwent sagittal fast spin-echo inversion recovery imaging. Lingual tonsils were identified and measured in the greatest anteroposterior diameter. Lingual tonsils > 10 mm were considered markedly enlarged. The subgroup with absent palatine tonsils (previous tonsillectomy) (n = 41) were compared with those with palatine tonsils present (n = 30).

RESULTS

Forty-four (62%) of the obese children had measurable lingual tonsils, which is greater than the frequency previously reported in normal subjects (0%), subjects with obstructive sleep apnea (33%), or subjects with Down syndrome and obstructive sleep apnea (50%). Ten (14%) had lingual tonsils > 10 mm. Obese subjects with absent palatine tonsils (previous tonsillectomy) had a higher prevalence of measurable lingual tonsils than those with palatine tonsils (78% vs 22%, respectively; p < 0.001) and a higher prevalence of lingual tonsils > 10 mm (90% vs 10%, p < 0.001).

CONCLUSION

Obese children have a high frequency of enlargement of the lingual tonsils with a significantly higher prevalence in those with previous tonsillectomy. Enlarged lingual tonsils may play a role in the pathogenesis of obstructive sleep apnea in obese children.

Upper airway volume segmentation analysis using cine MRI findings in children with tracheostomy tubes

OBJECTIVE

The purpose of this study is to evaluate the airway dynamics of the upper airway as depicted on cine MRI in children with tracheotomy tubes during two states of airflow through the upper airway.

MATERIALS AND METHODS

Sagittal fast gradient echo cine MR images of the supra-glottic airway were obtained with a 1.5T MRI scanner on seven children with tracheotomy tubes. Two sets of images were obtained with either the tubes capped or uncapped. The findings of the cine MRI were retrospectively reviewed. Volume segmentation of the cine images to compare the airway volume change over time (mean volume, standard deviation, normalized range, and coefficient of variance) was performed for the capped and uncapped tubes in both the nasopharynx and hypopharynx (Signed Rank Test).

RESULTS

Graphical representation of the airway volume over time demonstrates a qualitative increased fluctuation in patients with the tracheotomy tube capped as compared to uncapped in both the nasopharyngeal and hypopharyngeal regions of interest. In the nasopharynx, the mean airway volume (capped 2.72 mL, uncapped 2.09 mL, p = 0.0313), the airway volume standard deviation (capped 0.42 mL, uncapped 0.20 mL, p = 0.0156), and the airway volume range (capped 2.10 mL, uncapped 1.09 mL, p = 0.0156) were significantly larger in the capped group of patients. In the hypopharynx, the airway volume standard deviation (capped 1.54 mL, uncapped 0.67 mL, p = 0.0156), and the airway volume range (capped 6.44 mL, uncapped 2.93 mL, p = 0.0156) were significantly larger in the capped tubes. The coefficient of variance (capped 0.37, uncapped 0.26, p = 0.0469) and the normalized range (capped 1.52, uncapped 1.09, p = 0.0313) were significantly larger in the capped tubes.

CONCLUSION

There is a statistically significant change in airway dynamics in children with tracheotomy tubes when breathing via the airway as compared to breathing via the tracheotomy tube.

Diseases Associated with Childhood Obesity

OBJECTIVE

Radiologists can play an active role in children's health by increasing awareness of diseases associated with obesity. This article reviews key imaging findings in obesity-related diseases, current issues in imaging obese children, and treatment strategies.

CONCLUSION

There has been a well-documented pediatric obesity epidemic and a dramatic increase in clinical diseases associated with it. These serious health consequences affect nearly every organ system. Despite the increasing prevalence of obesity and the associated health hazards, pediatric obesity as a diagnosis is often overlooked by health care providers.

Comparison of lingual tonsil size as depicted on MR imaging between children with obstructive sleep apnea despite previous tonsillectomy and adenoidectomy and normal controls

BACKGROUND

Cine MRI has become a useful tool in the evaluation of patients with persistent obstructive sleep apnea (OSA) despite previous surgical intervention and in patients with underlying conditions that render them susceptible to multilevel airway obstruction. Findings on cine MRI studies have also increased our understanding of the mechanisms and anatomic causes of OSA in children.

OBJECTIVE

To compare lingual tonsil size between children with OSA and a group of normal controls. In addition, a subanalysis was made of the group of children with OSA comparing lingual tonsils between children with and without underlying Down syndrome.

MATERIALS AND METHODS

Children with persistent OSA despite previous palatine tonsillectomy and adenoidectomy and controls without OSA underwent MR imaging with sagittal fast spin echo inversion-recovery images, and lingual tonsils were categorized as nonperceptible at imaging or present and measurable. When present, lingual tonsils were measured in the maximum anterior-posterior diameter. If lingual tonsils were greater than 10 mm in diameter and abutting both the posterior border of the tongue and the posterior pharyngeal wall, they were considered markedly enlarged.

RESULTS

There were statistically significant differences between the OSA and control groups for the presence vs. nonvisualization of lingual tonsils (OSA 33% vs. control 0%, P=0.0001) and mean diameter of the lingual tonsils (OSA 9.50 mm vs. control 0.0 mm, P=0.00001). Within the OSA group, there were statistically significant differences between children with and without Down syndrome for the three lingual tonsil width categories (P=0.0070) and occurrence of markedly enlarged lingual tonsils (with Down syndrome 35% vs. without Down syndrome 3%, P=0.0035).

CONCLUSIONS

Enlargement of the lingual tonsils is relatively common in children with persistent obstructive sleep apnea after palatine tonsillectomy and adenoidectomy. This is particularly true in patients with Down syndrome.