Correlation on cine MR imaging of size of adenoid and palatine tonsils with degree of upper airway motion in asymptomatic sedated children

Differences of Craniofacial Characteristics in Oral Breathing and Pediatric Obstructive Sleep Apnea

BACKGROUND

Oral breathing (OB) was considered associated with specific craniofacial structures and same for pediatric obstructive sleep apnea (OSA). This study aimed to investigate the differences of craniofacial structures between OB and OSA.

METHODS

In this retrospective study, 317 children under age 18 years were recruited and divided into OB group, OSA group, and control group. OSA group (15 boys, 4 girls) were referred from qualified sleep center and diagnosed as pediatric OSA with full-night polysomnography. OB group (10 boys, 10 girls) were mostly referral from pediatric or ENT department, some of whom undertook polysomnography and were not OSA. Control group consisted of orthodontic patients within the same period. Lateral cephalograms were obtained in all groups and their parameters were compared with Chinese normal values and each other.

RESULTS

R-PNS of OB group (18.04 ± 2.49 mm) was greater than OSA group (14.27 ± 4.36 mm) and even control group (16.22 ± 3.91 mm) (P < 0.01). U1-NA was also the greatest in OB group (7.15 ± 2.92 mm), followed by OSA group (4.88 ± 2.66 mm), while control group was the smallest (5.71 ± 2.94 mm) (P < 0.05). In addition, OB group presented the smallest adenoids and tonsils among three groups. Bony nasopharynx development, mandibular length and growth direction of mandible of OB group were all better than OSA group.

CONCLUSION

Despite of oral breathing, anatomical morphology (well-developed dentoalveolar structures; mild adenotonsillar hypertrophy) might protect children from developing OSA.

Size of the Tonsil on Ultrasound in Children Without Tonsil-Associated Symptoms

This study was performed to establish the reference for tonsil size in children, including neonates, without tonsil-associated symptoms, in relation to anthropometric indices (sex/age/height/weight/body mass index).We evaluated the size of both tonsils in 362 children by ultrasonography. Tonsil size was calculated as 0.523abc (a, transverse diameter on the transverse image; b, longitudinal diameter on the transverse image; c, longitudinal diameter on the longitudinal image) and compared between each age year using the Wilcoxon signed rank sum test with Bonferroni correction. We evaluated the relationships between tonsil size and anthropometric indices.Among these children, tonsil size was significantly increased by the age of 3 years (0-1 vs 1-2 [volume (right) = 210.15 ± 205.27 vs 737.83 ± 335.72 mm, P (right) < 0.0001 and volume (left) = 218.26 ± 207.23 vs 645.33 ± 240.31 mm, P (left) < 0.0001]; 1-2 vs 2-3 [volume (right) = 737.83 ± 335.72 vs 1073.86 ± 468.21 mm, P (right) = 0.004 and volume (left) = 645.33 ± 240.31 vs 1109.73 ± 563.20 mm, P (left) < 0.0001]). Although there was a tendency for the tonsil size to increase in years 3-12, there was no significant difference. Using single linear regression analysis, we found a correlation between tonsil size and age (r right/left = 0.67/0.65), height (r right/left = 0.72/0.70), and weight (r right/left = 0.66/0.64), with height having the strongest correlation.In conclusion, tonsil size significantly increased by 3 years of age. Tonsil size was correlated with anthropometric indices, with height showing the strongest correlation.

MRI evaluation of distance between tonsillary fossa and internal carotid artery in children

OBJECTIVES

The presence of the internal carotid artery (ICA) near tonsils can also cause severe bleeding during a tonsillectomy. We investigated the relationship between tonsil width and volume; and superior, middle and inferior tonsil-ICA distances in 5-9 and 10-15 years of age children.

METHODS

Cranial MRI images of 200 children between 5 and 15 years of age were evaluated retrospectively. There were 100 children in group 1 (5-9 years of age) and 100 children in group 2 (10-15 years of age). Palatine tonsil width and volume; and superior, middle and inferior tonsil-internal carotid artery (ICA) measurements were performed bilaterally.

RESULTS

Our results showed that bilateral tonsil width and volume; and left superior, middle and inferior tonsil-ICA distance of 5-9 years of age group were lower than those of the 10-15 year-of age group (p < 0.05). The nearest distance between ICA and palatine tonsil is at the inferior tonsil-ICA distance side in both age groups. Especially mean inferior and middle tonsil-ICA distances were lower than 8 mm in 5-9 years of age group and lower than 9 mm in 10-15 years of age group. Minimum middle tonsil-ICA distances were 2.0-2.50 mm in smaller children and 2.0-3.50 mm in older children. Similarly, the minimum inferior tonsil-ICA distances were 2.00 mm in smaller children and 2.20-3.00 mm in older children. There were positive correlations between tonsil width, volume, and superior tonsil-ICA distance; and middle and inferior tonsil-ICA distances (p < 0.05).

CONCLUSION

In younger children, lower tonsil width; and in all children, lower tonsil volume can be a warning sign in terms of lower tonsil superior-ICA distance. During tonsillectomies, working at the middle and inferior tonsillary fossa, maximum attention must be performed for the possibility of the ICA being very closer to the tonsil to avoid unwanted bleedings.

Comparison of adenoid assessment by flexible endoscopy and mirror exam

OBJECTIVE

Assessment of adenoid hypertrophy can be completed through various methods including flexible endoscopy and intraoperative mirror exam. The objective of this study was to compare the effect of adenoid size on the accuracy of these techniques.

METHODS

Patients younger than 18 years old who underwent adenoidectomy at Boston Medical Center from October 2012 to December 2018 and had documented preoperative and intraoperative adenoid sizes were included. Cases were identified through Current Procedural Terminology (CPT) codes 42,830 and 42,831 with exclusion of CPT 42820 for tonsillectomy and adenoidectomy. Patients who had less obstruction (75% or less obstruction) and more obstruction (>75%) were compared using Chi-square analysis and t-tests.

RESULTS

Of 276 patients who underwent adenoidectomy from October 2012 to December 2018, 84 patients had adenoid size determined both preoperatively by flexible endoscopy and intraoperatively. Thirty-eight (45.2%) patients had intraoperative adenoids that were characterized as less obstructive hypertrophy and 46 (54.8%) had intraoperative adenoids that were characterized as more obstructive hypertrophy. In patients with less obstruction, the mean preoperative adenoid obstruction size of 72% was significantly higher than the mean intraoperative adenoid obstruction size of 63% (p = 0.0212). However, in patients with more obstruction, the mean preoperative adenoid size of 86% was not significantly different from the mean intraoperative adenoid size of 90% (p = 0.1237).

CONCLUSION

Adenoid assessment by flexible endoscopy and intraoperative mirror exam may not correlate as closely in patients who have less obstructive hypertrophy.

Role of dynamic sleep MRI in obstructive sleep apnea syndrome

PURPOSE

To identify obstruction sites of the upper airway during sleep in patients with obstructive sleep apnea syndrome (OSAS) under dynamic conditions and improve knowledge to guide surgical treatment and advancements.

MATERIALS AND METHODS

The study included 15 patients (5 females and 10 males) who were diagnosed as having OSAS. Overall mean age was 40.2 years (± 7.01 years). All the patients underwent drug-induced sleep endoscopy (DISE) and dynamic sleep MRI. The presence, location, and direction of airway collapse were assessed. Dynamic MRI findings were correlated to DISE. Data of the site and direction of airway collapse were correlated with those of endoscopic findings and interobserver agreement was done.

RESULTS

The dynamic images in sagittal section showed collapse of the upper airway at retropalatal level in 14 patients (93.33%) and at retroglossal level in seven patients (46.7%) and of these 14 patients; seven had combined retropalatal and retroglossal collapse. These findings were highly correlated with DISE findings with an excellent interobserver agreement for retropalatal and retroglossal levels (Kappa = 1 and 0.867, P value = 0.000), respectively. Objective measurements of the direction of collapse in axial dynamic sleep MRI images showed significant statistical correlation with endoscopic findings regarding retropalatal anteroposterior and circumferential collapse (Kappa = 0.58 and 0.52, P value = 0.02 and 0.03, respectively).

CONCLUSION

Dynamic sleep MRI can reliably characterize the actual site of dynamic airway obstruction and has the potential of improving predictions of successful surgical outcomes in OSAS patients.

Normal palatine tonsil size in healthy children: a sonographic study

OBJECTIVES

Magnetic resonance imaging (MRI) and computerized tomography (CT) have been widely used to assess palatine tonsils. However, these imaging modalities have some limitations, such as high costs, need for sedation, and exposure to ionizing radiation. Ultrasound has been increasingly used to diagnose tonsillar pathologies. We aim to define normal tonsil size and volume of healthy children according to age.

METHODS

A total of 274 healthy children were included. Both right and left tonsil sizes were measured in anteroposterior (AP), transverse (Tr.), and longitudinal (Long.) planes. Patients were divided into six subgroups according to their age, and analysis was performed for these subgroups. Age, sex, height, weight, and body mass index were recorded to find possible correlations.

RESULTS

Median age of the whole population was 7 years (0-16 years). Mean tonsil volume is 1.5 ± 0.9 cm³ for right and left sides. We cannot detect any significant correlation between PT values and sex. We detected a significant positive correlation between PT values and height, weight and BMI.

CONCLUSION

US can be used as a diagnostic tool for PT pathologies. PT size correlates with age, height, weight, and BMI; however, no correlation is present for sex and side.

Assessment of Tonsil Volume With Transcervical Ultrasonography in Both Children and Adults

OBJECTIVES

To investigate the success of ultrasonography (USG) in the objective measurement of palatin tonsil volume in both children and adults and to compare those results with clinical findings.

METHODS

Eighty-five patients, who were scheduled to undergo tonsillectomy with the indications of recurrent tonsillitis and obstructive sleep apnea syndrome, were included in the study. The tonsil grades of the patients were recorded according to the Friedman tonsil grading. The tonsil size and volume were measured with transcervical USG. After tonsillectomy, the volumes of the tonsils were calculated by the displacement method. The correlation between the obtained data was evaluated. In all analyses, P < .05 was accepted as a statistical level of significance.

RESULTS

Fifty children and 35 adults were included in the study. In children, the mean actual volume ± SD of 100 tonsils was measured as 3.5 ± 1.45 mL, and the USG volume was 3.67 ± 1.59 mL; a high correlation was found between both methods (r = 0.842; P < .05). In adults, the mean actual volume of 70 tonsils was measured as 5.15 ± 2.25 mL, and the USG volume was 5.71 ± 2.98 mL; a moderate correlation was found between the methods (r = 0.589; P < .05). In children, a moderate correlation was found between the Friedman grading and the USG (r = 0.532; P < .05), and actual (r = 0.549; P < .05) tonsil volumes. In adults, a low correlation was found between the Friedman grading and the USG (r = 0.363; P < .05) and actual (r = 0.384; P < .05) tonsil volumes.

CONCLUSIONS

Ultrasonography is a useful, accessible, and noninvasive imaging method for objective measurement of tonsil volume in adults and children.

The anatomy of the pediatric airway: Has our knowledge changed in 120 years? A review of historic and recent investigations of the anatomy of the pediatric larynx

BACKGROUND

There is disagreement regarding the anatomy of the pediatric airway, particularly regarding the shape of the cricoid cartilage and the location of the narrowest portion of the larynx.

AIMS

The aim of this review is to clarify the origin and the science behind these differing views.

METHODS

We undertook a review of published literature, University Libraries, and authoritative textbooks with key search words and phrases.

RESULTS

In vivo observations suggest that the narrowest portion of the airway is more proximal than the cricoid cartilage. However, in vitro studies of autopsy specimens measured with rods or calipers, confirm that the nondistensible and circular or near circular cricoid outlet is the narrowest level. These anatomic studies confirmed the classic "funnel" shape of the pediatric larynx. In vivo studies are potentially misleading as the aryepiglottic, vestibular, and true vocal folds are in constant motion with respiration. These studies also do not consider the effects of normal sleep, inhalation agents, and comorbidities such as adenoid or tonsil hypertrophy that cause some degree of pharyngeal collapse and alter the normal movement of the laryngeal tissues. Thus, the radiologic studies suggesting that the narrowest portion of the airway is not the cricoid cartilage may be the result of an artifact depending upon which phase of respiration was imaged.

CONCLUSION

In vivo studies do not take into account the motion of the highly pliable laryngeal upper airway structures (aryepiglottic, vestibular, and vocal folds). Maximal abduction of these structures with tracheal tubes or bronchoscopes always demonstrates a larger opening of the glottis compared to the outlet of the cricoid ring. Injury to the larynx depends upon ease of tracheal tube or endoscope passage past the cricoid cartilage and not passage through the readily distensible more proximal structures. The infant larynx is funnel shaped with the narrowest portion the circular or near circular cricoid cartilage confirmed by multiple in vitro autopsy specimens carried out over the past century.

Evaluation of the Normal Tonsils in Pediatric Patients With Ultrasonography

OBJECTIVES

To evaluate how well the tonsils can be viewed, in addition to echogenicity, using ultrasound, and to compare these results between children younger and older than the age of 3.

METHODS

We evaluated the tonsils of 99 patients (72.0 ± 59.1 months) by ultrasound. Ultrasound scans of both the left and right side, in both the transverse and longitudinal planes, were obtained. Images were scored with one of four grades according to how well the tonsil border could be distinguished, 0 being the worst and 3 being the best. Grades 2 or 3 (>50% of the tonsil border was detectable) in both tonsils, in either the transverse or longitudinal image, were considered "evaluable." Echogenicity was designated as imperceptible, low echoic, or striated in appearance. Statistical analysis was performed using the Mann-Whitney U test.

RESULTS

Bilateral tonsils were evaluable in 96.0% (96/99) of cases. The mean grades were 2.44 ± 0.65/2.03 ± 0.68 in the right transverse/longitudinal images, and 2.40 ± 0.59/2.12 ± 0.73 in the left transverse/longitudinal images. The grades in children older than the age of 3 were significantly higher than those in younger patients (all P < .05). Echogenicity classification on the right and left side revealed a striated appearance in 97.0% (96/99) and 90.0% (89/99) of cases, respectively.

CONCLUSIONS

The tonsils of almost all pediatric patients could be evaluated by ultrasound, particularly for patients older than 3 years. Additionally, a striated pattern of the tonsils was observed in most cases.

Palatine tonsil volume estimation using different methods after tonsillectomy

This study was carried out to measure the volume of the palatine tonsil in otorhinolaryngology outpatients with complaints of adenotonsillar hypertrophy and chronic tonsillitis who had undergone tonsillectomy. To date, no study has investigated palatine tonsil volume using different methods and compared with subjective tonsil size in the literature. For this purpose, we used three different methods to measure palatine tonsil volume. The correlation of each parameter with tonsil size was assessed. After tonsillectomy, palatine tonsil volume was measured by Archimedes, Cavalieri and Ellipsoid methods. Mean right-left palatine tonsil volumes were calculated as 2.63 ± 1.34 cm³ and 2.72 ± 1.51 cm³ by the Archimedes method, 3.51 ± 1.48 cm³ and 3.37 ± 1.36 cm³ by the Cavalieri method, and 2.22 ± 1.22 cm³ and 2.29 ± 1.42 cm³ by the Ellipsoid method, respectively. Excellent agreement was found among the three methods of measuring volumetric techniques according to Bland-Altman plots. In addition, tonsil grade was correlated significantly with tonsil volume.

Optical coherence tomography and autofluorescence imaging of human tonsil

For the first time, we present co-registered autofluorescence imaging and optical coherence tomography (AF/OCT) of excised human palatine tonsils to evaluate the capabilities of OCT to visualize tonsil tissue components. Despite limited penetration depth, OCT can provide detailed structural information about tonsil tissue with much higher resolution than that of computed tomography, magnetic resonance imaging, and Ultrasound. Different tonsil tissue components such as epithelium, dense connective tissue, lymphoid nodules, and crypts can be visualized by OCT. The co-registered AF imaging can provide matching biochemical information. AF/OCT scans may provide a non-invasive tool for detecting tonsillar cancers and for studying the natural history of their development.

Obstructive sleep apnea and asthma

Symptoms of sleep-disordered breathing, especially obstructive sleep apnea syndrome (OSAS), are common in asthma patients and have been associated with asthma severity. It is known that asthma symptoms tend to be more severe at night and that asthma-related deaths are most likely to occur during the night or early morning. Nocturnal symptoms occur in 60-74% of asthma patients and are markers of inadequate control of the disease. Various pathophysiological mechanisms are related to the worsening of asthma symptoms, OSAS being one of the most important factors. In patients with asthma, OSAS should be investigated whenever there is inadequate control of symptoms of nocturnal asthma despite the treatment recommended by guidelines having been administered. There is evidence in the literature that the use of continuous positive airway pressure contributes to asthma control in asthma patients with obstructive sleep apnea and uncontrolled asthma.

The prevalence and clinical importance of incidental soft-tissue findings in cervical CT scans of trauma population

OBJECTIVES

To define the age-related prevalence of incidental soft-tissue findings in cervical CT scans of a trauma population and to investigate their clinical importance.

METHODS

The original diagnostic radiology reports and the CT images of the 357 patients with cervical trauma were retrospectively evaluated. Incidental soft-tissue findings were investigated. All findings were grouped according to age. The findings were classified based on their clinical importance into three categories: Category 1: no clinical importance, Category 2: possible clinical importance requiring further investigation and Category 3: obvious clinical importance. In addition, the medical records of the patients were investigated. The follow-up ratio of the pathologies mentioned in the original radiology report was recorded.

RESULTS

The most frequently encountered findings in Categories 2 and 3 were carotid artery calcification (n = 89, 24.9%) and tonsillolith (n = 115, 32.2%), respectively. The reporting ratio in the original reports of Categories 1, 2 and 3 findings was 1.1% (n = 4), 9% (n = 27) and 34.5% (n = 64), respectively. No further investigations and follow-up was accomplished for Category 1 lesions, whereas 11.1% of Category 2 and 35.9% of Category 3 lesions were subjected to further investigations and follow-up.

CONCLUSIONS

The cervical CT scans of trauma patients reveal many clinically important soft-tissue incidental findings. Cervical region incidental findings may be followed up on an outpatient basis, rarely being of life-threatening value. The ratio of reporting and follow-up of incidental findings increases parallel to the clinical importance of the lesions.

MRI and MR sialography of juvenile recurrent parotitis

BACKGROUND

Juvenile recurrent parotitis (JRP) is the second most common inflammatory salivary gland disease of childhood, after mumps. Diagnosis of JRP is usually based on clinical history of recurrent unilateral or bilateral parotid swelling and demonstration of sialectasis. Conventional sialography, digital sialography, US, MRI and sialoendoscopy have been used as investigative tools for the diagnosis of JRP. MR sialography is increasingly recognized as a useful supplement to sialography in salivary duct disorders.

OBJECTIVE

To describe the MRI and MR sialographic findings in children with JRP.

MATERIALS AND METHODS

MR Sialography was performed using T2-weighted three-dimensional constructive interference in steady-state (CISS) and half fourier acquisition single-shot turbo spin-echo (HASTE) sequences in 62 children with inflammatory salivary gland disease. Out of these 62 children, 6 had JRP. Axial T1- and T2-W images were also performed.

RESULTS

The main parotid duct was normal in all six children with JRP. High signal intensity focal lesions suggestive of sialectasis were seen involving both parotid glands in all six children. CISS sequence demonstrated the intraglandular ducts and sialectasis better than HASTE images.

CONCLUSION

MRI and MR sialography can non-invasively delineate the parenchymal and ductal system abnormalities of the parotid glands in children with JRP. Although MR and MR sialography cannot substitute US, they can accurately depict findings such as sialectasis and signal intensity changes in the parotid gland depending upon the phase of the disease (acute vs. chronic inflammation). The radiologist should be familiar with MR findings of JRP.

Adenotonsillectomy in the context of obstructive sleep apnoea

Adenotonsillectomy (T&A) is a common surgical procedure. Its frequency is highest in the paediatric age range and its most common current indication is obstructive sleep apnoea (OSA). Sleep studies are used to document the presence and severity of OSA. This review will focus on indications for and complications of T&A in the context of the age range and setting where this surgery is undertaken for OSA in children.

Cine Magnetic Resonance Imaging: Evaluation of Persistent Airway Obstruction after Tonsil and Adenoidectomy in Children with Down Syndrome

OBJECTIVE/HYPOTHESIS

Although usually successful, not all obstructive sleep apnea is cured by removal of the tonsils and adenoids (T&A). This is particularly true in children with Down syndrome and craniofacial anomalies. This is because of the multiple levels of obstruction in their airways, with obstruction present not only at the level of the tonsils and adenoids but also from base of tongue obstruction, soft palate collapse, and hypopharyngeal collapse. The cine magnetic resonance image (MRI) is useful in evaluating the upper airway in those patients who have not achieved a normal polysomnogram after T&A surgery.

STUDY DESIGN

Prospective case series.

METHODS

Fifteen children with Down syndrome who had previously undergone a T&A but continued to have abnormal postoperative polysomnograms underwent a cine MRI with fast gradient cine MRI images.

RESULTS

The cine MRI identified different areas and levels of obstruction that ultimately affected the children's treatment courses. Recurrent adenoid tissue, glossoptosis, soft palate collapse, hypopharyngeal collapse, and enlarged lingual tonsils were identified. The results as well as several illustrative cases are presented.

CONCLUSION

Cine MRI evaluates upper airway obstruction in children who may have multiple sources of obstruction causing their obstructive sleep apnea. This is particularly helpful in children with Down syndrome and craniofacial anomalies. This technology is useful in all children with complex upper airway obstruction.

A comparative study of the breathing pattern and amount of nasopharynx obstruction by the pharyngeal tonsil in HIV infected and non infected children

Aim: the goal of the present investigation was to study the association between breathing pattern and pharyngeal tonsil size in 122 children (60 HIV infected and 62 without such infection). Material and Methods: The children were analyzed as to their breathing pattern, nasal flow and pharyngeal tonsil obstruction seen in side cephalometric x-rays, by means of a computerized analysis. Results: The pattern that most occurred in both groups was the mixed type. Most of the children presented oral or mixed type breathing and there was no association between the type of breathing and HIV presence (p=0.091). Nasal flow was mainly medium in both groups. Children without prior history of HIV infection had medium to large nasal flow and most of the HIV-infected children had medium nasal airflow. There was a positive association between nasal flow and HIV infection (p<0.0001). The average percentage of nasopharynx obstruction by the pharyngeal tonsil was high in both groups, and there was no statistically significance difference between them. Children from both groups had a moderate or large size of pharyngeal tonsil, and there was no association between tonsil size and HIV (p=0.21).

Pathophysiology of pediatric obstructive sleep apnea

Sleep-disordered breathing is a common and serious cause of metabolic, cardiovascular, and neurocognitive morbidity in children. The spectrum of obstructive sleep-disordered breathing ranges from habitual snoring to partial or complete airway obstruction, termed obstructive sleep apnea (OSA). Breathing patterns due to airway narrowing are highly variable, including obstructive cycling, increased respiratory effort, flow limitation, tachypnea, and/or gas exchange abnormalities. As a consequence, sleep homeostasis may be disturbed. Increased upper airway resistance is an essential component of OSA, including any combination of narrowing/retropositioning of the maxilla/mandible and/or adenotonsillar hypertrophy. However, in addition to anatomic factors, the stability of the upper airway is predicated on neuromuscular activation, ventilatory control, and arousal threshold. During sleep, most children with OSA intermittently attain a stable breathing pattern, indicating successful neuromuscular activation. At sleep onset, airway muscle activity is reduced, ventilatory variability increases, and an apneic threshold slightly below eupneic levels is observed in non-REM sleep. Airway collapse is offset by pharyngeal dilator activity in response to hypercapnia and negative lumenal pressure. Ventilatory overshoot results in sudden reduction in airway muscle activation, contributing to obstruction during non-REM sleep. Arousal from sleep exacerbates ventilatory instability and, thus, obstructive cycling. Paroxysmal reductions in pharyngeal dilator activity related to central REM sleep processes likely account for the disproportionate severity of OSA observed during REM sleep. Understanding the pathophysiology of pediatric OSA may permit more precise clinical phenotyping, and therefore improve or target therapies related to anatomy, neuromuscular compensation, ventilatory control, and/or arousal threshold.

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.

Monitored anesthesia care with a combination of ketamine and dexmedetomidine during magnetic resonance imaging in three children with trisomy 21 and obstructive sleep apnea

We present a series of three children with trisomy 21 and obstructive sleep apnea who required sedation during magnetic resonance imaging of the upper airway. In an effort to provide effective sedation with limited effects on cardiovascular and ventilatory function, sedation was provided by a combination of ketamine and dexmedetomidine. Sedation was initiated with a bolus dose of ketamine (1 mg x kg(-1)) and dexmedetomidine (1 microg x kg(-1)) and maintained by a continuous infusion of dexmedetomidine (1 microg x kg(-1) x h(-1)). One patient required a repeat of the bolus doses of ketamine and dexmedetomidine and an increase of the dexmedetomidine infusion to 2 microg x kg(-1) x h(-1). Effective sedation was provided for all three patients. We noted no clinically significant hemodynamic or respiratory effects. No central apnea was noted although there was a brief episode of upper airway obstruction in one patient which responded to repositioning of the airway. All three patients developed some degree of hypercarbia with maximum P(E)(CO2) values of 6.4, 6.9, and 6.8 kPa (49, 53, and 52 mmHg), respectively. To date, this is the first report regarding the use of this combination in pediatric patients. Given the preliminary success noted in our three patients, prospective trials evaluating the efficacy of a dexmedetomidine-ketamine combination appears warranted.

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.

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

Cine magnetic resonance (MR) imaging sleep studies have become a useful tool in the evaluation of obstructive sleep apnea in children with certain categories of pathologic conditions. In this article, the author describes a program for the use of cine MR sleep studies in the evaluation of children with obstructive sleep apnea. The following areas are discussed: clinical indications, patient preparation, anatomic considerations, MR technique, technical issues, image interpretation, commonly encountered diagnoses, volume segmentation processing of data, and controversial areas.

Changes in upper airway size during tidal breathing in children with obstructive sleep apnea syndrome

We performed respiratory-gated magnetic resonance imaging to evaluate airway dynamics during tidal breathing in 10 children with obstructive sleep apnea syndrome (OSAS; age, 4.3 +/- 2.3 years) and 10 matched control subjects (age, 5.0 +/- 2.0 years). We hypothesized that respiratory cycle fluctuations in upper airway cross-sectional area would be larger in children with OSAS.

METHODS

Studies were performed under sedation. Respiratory gating was performed automatically at 10, 30, 50, 70, and 90% of inspiratory and expiratory volume. Airway cross-sectional area was measured at four ascending oropharyngeal levels at each increment of the respiratory cycle.

RESULTS

We noted the following in subjects with OSAS compared with control subjects: (1) a smaller upper airway cross-sectional area, particularly during inspiration; (2) airway narrowing occurred during inspiration without evidence of complete airway collapse; (3) airway dilatation occurred during expiration, particularly early in the phase; and (4) magnitude of cross-sectional areas fluctuations during tidal breathing noted in OSAS at levels 1 through 4 were 317, 422, 785, and 922%, compared with 19, 15 17, and 24% in control subjects (p < 0.001, p < 0.005, p < 0.001, and p < 0.001, respectively).

CONCLUSIONS

Fluctuations in airway area during tidal breathing are significantly greater in subjects with OSAS compared with control subjects. Resistive pressure loading is a probable explanation, although increased airway compliance may be a contributing factor.

The clinical significance of adenoid-choanae area ratio in children with adenoid hypertrophy

OBJECTIVE

We designed a method to compare the adenoid-choanae area ratio (A/C ratio) measured in children with symptoms of adenoid hypertrophy with those from children without any symptoms related to adenoid hypertrophy.

METHODS

A prospective analysis of A/C ratio of 42 patients undergoing adenoidectomy and tonsillectomy from January 2000 to September 2003 in a medical center was compared with 28 patients receiving treatment other than the above-mentioned procedures in the same period. We used 0 degrees telescope to take pictures of the nasopharynx under general anesthesia preoperatively. The pictures were transformed digitally. The A/C ratio was calculated by the program we developed after these pictures were processed by the Photoshop 6.0 (Adobe, USA) software.

RESULTS

The A/C ratio in adenoid hypertrophy group (0.863+/-0.0983) is significantly higher (p<0.001) than that of control group (0.445+/-0.1431). Mouth breathing, nasal obstruction and snoring were found to be more severe in children with high A/C ratio (p<0.001).

CONCLUSIONS

The A/C ratio provided the two-dimensional information of the nasopharyngeal airway. The A/C area ratio is significantly higher in the group of symptomatic adenoid hypertrophy when compared with symptomatic-free group. For practical purposes, the adenoid with an A/C ratio more than 2/3 is considered a pathological enlargement.

Avaliação radiográfica da adenóide em crianças: métodos de mensuração e parâmetros da normalidade

A radiografia da nasofaringe (ou radiografia do cavum) ainda é o exame por imagem mais usado para a avaliação do tamanho da adenóide. Dada a variedade e a complexidade dos métodos de mensuração preconizados, muitos radiologistas preferem a avaliação subjetiva, que pode ser imprecisa e não-acurada. Esta revisão enumera e descreve os diversos métodos de mensuração radiográfica da adenóide propostos na literatura, considerando praticidade, acurácia e precisão, com o objetivo de indicar os mais adequados para a prática cotidiana.

Causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with down syndrome as depicted on static and dynamic cine MRI

OBJECTIVE

Our purpose was to evaluate the causes of persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy in children with Down syndrome as depicted on cine MRI.

MATERIALS AND METHODS

Cine MRI studies performed to evaluate persistent obstructive sleep apnea despite previous tonsillectomy and adenoidectomy were reviewed. MRI was performed under sedation and included cine MR images (fast gradient-echo) obtained in the midline sagittal plane and in the axial plane at the base of the tongue and T1-weighted spin-echo and fast spin-echo inversion recovery images in the axial and sagittal planes. Imaging parameters reviewed included static and dynamic diagnoses made, frequency of recurrence and diameter of tonsillar tissue, and tongue morphology.

RESULTS

Twenty-seven patients were identified (mean age, 9.9 years). Diagnoses included glossoptosis in 17 patients (63%), hypopharyngeal collapse in six (22%), recurrent and enlarged adenoid tonsils in 17 (63%), enlarged lingual tonsils in eight (30%), and macroglossia in 20 (74%). Of the 20 patients with macroglossia, 11 (55%) had absence of the normal median sulcus and 12 (60%) had evidence of fatty infiltration of the tongue musculature.

CONCLUSION

Persistent obstructive sleep apnea in children with Down syndrome who have undergone previous adenoidectomy and tonsillectomy has multiple causes. The most common causes include macroglossia, glossoptosis, recurrent enlargement of the adenoid tonsils, and enlarged lingual tonsils.

Obstructive Sleep Apnea: MR Imaging Volume Segmentation Analysis

PURPOSE

To retrospectively determine airway wall motion with volume segmentation of transverse cine magnetic resonance (MR) images in children with obstructive sleep apnea (OSA).

MATERIALS AND METHODS

Transverse fast gradient-echo cine MR images of the hypopharynx were obtained at 1.5 T in 31 children with OSA (eight girls, 23 boys; mean age, 11.3 years) and 21 children free of airway symptoms who underwent MR imaging for other clinical indications (11 girls, 10 boys; mean age, 3.5 years). Volume segmentation with a k-means clustering algorithm was applied to transverse cine MR images to quantify airway volumes at each time. Airway wall motion for each child was described with standard deviation and range. Coefficient of variance and normalized range, which are independent of airway size, were used to compare groups (Kruskal-Wallis test).

RESULTS

Plots of airway volume over time demonstrated large fluctuations during respiration in children with OSA and minimal fluctuations in controls; findings were consistent with airway distention and airway collapse in OSA. Average airway transverse volume was larger in the group with OSA than in the control group (OSA group, 2.52 mL; control group, 0.936 mL; P <.001). Mean standard deviation (OSA group, 0.840 mL; control group, 0.17 mL; P <.001) and mean range of airway cross section (OSA group, 3.552 mL; control group, 0.864 mL; P <.001) were larger in the group with OSA. Coefficient of variance (OSA group, 0.32; control group, 0.17; P <.001) and normalized range (OSA group, 1.42; control group, 0.96; P <.001) indicate statistically significant difference in airway dynamics in children with OSA.

CONCLUSION

Volume segmentation of transverse cine MR images of the hypopharynx aids in quantification of increased airway wall motion in children with OSA. Transverse MR imaging demonstrates both airway distention and collapse in children with OSA.