Multidetector computed tomography of pediatric large airway diseases: state-of-the-art

Foreign Bodies in Pediatric Otorhinolaryngology: A Review

Foreign bodies (FBs) in pediatric otorhinolaryngology represent up to 10% of cases in emergency departments (ED) and are primarily present in children under five years old. They are probably the result of children's curiosity and tendency to explore the environment. Aural and nasal FBs are the most common and accessible, and the removal methods differ depending on the exact location and type of FB, which can be organic or inorganic. A fish bone stuck in one of the palatine tonsils is the most common pharyngeal FB. Laryngopharyngeal FBs can obstruct the upper respiratory tract and thus become acutely life-threatening, requiring an urgent response. Aspiration of FBs is common in children between 1 and 4 years old. A history of coughing and choking is an indication of diagnostic and therapeutic methods to rule out or confirm a tracheobronchial FB. Regardless of the availability of radiological diagnostics, rigid bronchoscopy is the diagnostic and therapeutic method of choice in symptomatic cases. Radiological diagnostics are more significant in treating esophageal FBs since most are radiopaque. Flexible or rigid esophagoscopy is a successful method of removal. A delayed diagnosis, as with tracheobronchial FBs, can lead to fatal consequences.

Tuberculosis revisted: classic imaging findings in childhood

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.

Pediatric large airway imaging: evolution and revolution

Infants and children often present with respiratory symptoms referable to the airway. For these pediatric patients, airway imaging is frequently performed to evaluate for underlying disorders of the large airway. Various imaging modalities have been used to evaluate the pediatric large airway, and pediatric airway imaging techniques have continued to evolve. Therefore, clear understanding of the status and new advances in pediatric large airway imaging is essential for practicing radiologists to make timely and accurate diagnoses, which can lead to optimal pediatric patient management.

Lung and large airway imaging: magnetic resonance imaging versus computed tomography

Disorders of the respiratory system are common in children and imaging plays an important role for initial diagnosis and follow-up evaluation. Radiographs are typically the first-line imaging test for respiratory symptoms in children and, when advanced imaging is required, CT has been the most frequently used imaging modality. However, because of increasing concern about potentially harmful effects of ionizing radiation on children, there has been a shift toward MRI in pediatric imaging. Although MRI of chest in children presents many technical challenges, recent advances in MRI technology are overcoming many of these issues, and MRI is now being used for evaluating the lung and large airway in children at centers with expertise in pediatric chest MRI. In this article we review the state of pediatric lung and large airway imaging, with an emphasis on cross-sectional modalities and the roles of MRI versus CT.

Congenital lung lesions: a radiographic pattern approach

Congenital lung malformations represent a spectrum of abnormalities that can overlap in imaging appearance and frequently coexist in the same child. Imaging diagnosis in the neonatal period can be challenging; however, the recognition of several archetypal radiographic patterns can aid in narrowing the differential diagnosis. Major radiographic archetypes include (1) hyperlucent lung, (2) pulmonary cysts, (3) focal opacity and (4) normal radiograph. Here we review the multimodality imaging appearances of the most commonly seen congenital lung malformations, categorized by their primary imaging archetypes. Along with the congenital lung malformations, we present several important imaging mimickers.

Extravascular MDCT Findings of Pulmonary Vein Stenosis in Children with Cardiac Septal Defect

Purpose: To retrospectively investigate the extravascular thoracic MDCT angiography findings of pulmonary vein stenosis (PVS) in children with a cardiac septal defect. Materials and Methods: Pediatric patients (age ≤ 18 years) with cardiac septal defect and PVS, confirmed by echocardiogram and/or conventional angiography, who underwent thoracic MDCT angiography studies from April 2009 to April 2021 were included. Two pediatric radiologists independently evaluated thoracic MDCT angiography studies for the presence of extravascular thoracic abnormalities in: (1) lung and airway (ground-glass opacity (GGO), consolidation, pulmonary nodule, mass, cyst, septal thickening, fibrosis, and bronchiectasis); (2) pleura (pleural thickening, pleural effusion, and pneumothorax); and (3) mediastinum (mass and lymphadenopathy). Interobserver agreement between the two independent pediatric radiology reviewers was evaluated with kappa statistics. Results: The final study group consisted of 20 thoracic MDCT angiography studies from 20 consecutive individual pediatric patients (13 males (65%) and 7 females (35%); mean age: 7.5 months; SD: 12.7; range: 2 days to 7 months) with cardiac septal defect and PVS. The characteristic extravascular thoracic MDCT angiography findings were GGO (18/20; 90%), septal thickening (9/20; 45%), pleural thickening (16/20; 80%), and ill-defined, mildly heterogeneously enhancing, non-calcified soft tissue mass (9/20; 45%) following the contours of PVS in the mediastinum. There was a high interobserver kappa agreement between two independent reviewers for detecting extravascular abnormalities on thoracic MDCT angiography studies (k = 0.99). Conclusion: PVS in children with a cardiac septal defect has a characteristic extravascular thoracic MDCT angiography finding. In the lungs and pleura, GGO, septal thickening, and pleural thickening are frequently seen in children with cardiac septal defect and PVS. In the mediastinum, a mildly heterogeneously enhancing, non-calcified soft tissue mass in the distribution of PVS in the mediastinum is seen in close to half of the pediatric patients with cardiac septal defect and PVS.

Foreign bodies of body orifices: A pictorial review

INTRODUCTION

Ingestion, inhalation, and insertion of foreign bodies (FB) are commonly encountered problems in the emergency departments (ED). Radiologists pay a key role in their diagnosis and management. Selecting an appropriate imaging modality is important depending on the route of entry and reported type of FB. Diagnosing FB is time sensitive and requires radiologists to be astute and familiar with varied imaging appearances of FB. In this article, we review imaging features of most common FB seen in clinical practice and their complications.

TEACHING POINTS

SUMMARY: FB in body orifices are frequently seen in the ED. Imaging plays a pivotal role in the management in majority of the cases. In this article, we present several cases of commonly encountered FB.

Diagnostic utility of MDCT in evaluation of persistent stridor in children: Large airway causes and benefit of additional findings

OBJECTIVES

To assess the diagnostic utility of MDCT in the evaluation of persistent stridor in children for the underlying large airway causes and benefit of additional findings.

METHODS

All consecutive pediatric patients who underwent MDCT for the evaluation of persistent stridor from December 2018 to February 2020 were included. Two pediatric radiologists independently reviewed MDCT studies for the presence of abnormalities at six large airway levels: (1) nasopharynx, (2) oropharynx, (3) glottis, (4) subglottis, (5) trachea, and (6) mainstem bronchi. In addition, studies were evaluated for the presence of non-airway abnormalities. Interobserver agreement between two reviewers was evaluated with kappa statistics.

RESULTS

There were a total of 40 pediatric patients (age range: 1 day-4 years. MDCT detected large airway abnormalities in 20 (50%) out of 40 patients, including 4 (20%) in nasopharynx, 4 (20%) in glottis, 4 (20%) in trachea, 3 (15%) in subglottis, 3 (15%) in mainstem bronchi, and 2 (10%) in oropharynx. Non-airway abnormalities were seen in 13 (32.5%) children, including 9 (69%) in the lungs, 3 (23%) in the soft tissue, and 1 (8%) in the bone. The remaining 7 (17.5%) studies were normal. There was excellent interobserver agreement seen for detecting large airway and non-airway abnormalities (k > 0.90).

CONCLUSION

MDCT has high diagnostic utility in diagnosing large airway causes of persistent stridor in children. It can also provide additional information regarding non-airway abnormalities. Therefore, MDCT has the potential to be utilized as a noninvasive problem-solving imaging modality in pediatric patients with persistent stridor.

Large airway diseases in pediatrics: a pictorial essay

“Large airway diseases” is being used as an all-encompassing phrase to describe a broad spectrum of pathological entities, which involves the trachea, main, lobar, and segmental bronchi of up to 3 mm diameter. Imaging modalities such as radiography, computed tomography, and magnetic resonance imaging contribute to the identification and diagnosis of each entity. Knowledge of clinical information, normal cross-sectional anatomy, and imaging characteristics of large airway diseases is necessary for appropriate radiologic evaluation. This review provides information about congenital and acquired diseases of the large airways in the pediatric population.

Technique, pitfalls, quality, radiation dose and findings of dynamic 4-dimensional computed tomography for airway imaging in infants and children

This retrospective review of 33 children's dynamic 4-dimensional (4-D) computed tomography (CT) images of the airways, performed using volume scanning on a 320-detector array without anaesthesia (free-breathing) and 1.4-s continuous scanning, was undertaken to report technique, pitfalls, quality, radiation doses and findings. Tracheobronchomalacia (airway diameter collapse >28%) was recorded. Age-matched routine chest CT scans and bronchograms acted as benchmarks for comparing effective dose. Pitfalls included failure to administer intravenous contrast, pull back endotracheal tubes and/or remove nasogastric tubes. Twenty-two studies (67%) were diagnostic. Motion artefact was present in 16 (48%). Mean effective dose: dynamic 4-D CT 1.0 mSv; routine CT chest, 1.0 mSv, and bronchograms, 1.4 mSv. Dynamic 4-D CT showed tracheobronchomalacia in 20 patients (61%) and cardiovascular abnormalities in 12 (36%). Fourteen children (70%) with tracheobronchomalacia were managed successfully by optimising conservative management, 5 (25%) underwent surgical interventions and 1 (5%) died from the presenting disorder.

Tracheal bronchus diagnosed in children undergoing flexible bronchoscopy

This paper describes the clinical features of paediatric patients with tracheal bronchus (TB) identified with flexible bronchoscopy (FB) in a tertiary care hospital. A retrospective review of every FB with diagnosis of TB carried out in our centre since 1990 was performed which considered specifically: age at diagnosis, gender, semiology, somatic anomalies, tracheal bronchus type, other bronchoscopic findings and clinical progress. Out of 1665 FB in 1337 patients, TB was found in 26 (1.9%). The median age was 15 months (age range 1 month-13 years), with no gender differences. Of 26 patients, a total of 24 had associated congenital pathologies (92.3%) (heart disease 69%, chromosomal abnormality 35% and spinal fusion defect 11%). FB was performed for a number of reasons including: recurrent or persistent wheezing, pneumonia or atelectasis, persistent stridor and refractory cough. The type of TB identified was primarily ectopic lobar of the right upper lobe (73%) and the apical supernumerary (11.5%). In addition to TB, other defects were found by FB in 90% of cases, such as tracheomalacia, bronchomalacia or tracheal stenosis. The review confirmed a higher prevalence of TB than expected in previous series and highlighted its association with other airway or somatic malformations, notably congenital cardiac defects and spinal fusion defects. All patients were managed conservatively for the TB.

Dynamic expiratory CT: An effective non-invasive diagnostic exam for fragile children with suspected tracheo-bronchomalacia

BACKGROUND

Tracheobronchomalacia, defined as variable collapse of the airways, has been recognized as an important cause of respiratory morbidity but still widely underdiagnosed. Bronchoscopy is still considered as the gold standard, but numerous limitations are known, especially for fragile sick children. Moreover, information on parenchymal lung disease cannot be described. There is a real need for a reliable, non-invasive test to help detection of airway and parenchymal malformations in children, specifically when bronchoscopy cannot be performed.

METHODS AND RESULTS

34 paediatric patients underwent cine multidector CT for ongoing respiratory symptoms and were included. All CT images were of good quality and sedation was never needed. Airway disease such as trachea-broncomalacia with/without stenosis was described in 53% with the first being more frequent. Bronchomalacia alone was described in 10 patients and in 4 patients was associated with tracheomalacia. Moreover, CT allowed identification of parenchymal disease in 10 patients. Airways stenosis alone was detected in seven patients. The majority of patients (85%) underwent also bronchoscopy for clinical decision. The agreement between CT and bronchoscopy was explored. The two examinations did not agree only in two cases. CT dynamic showed an excellent sensitivity of 100% (81.47-100 %), a great specificity of 82% (48.22-97.72 %), NPV 100%, and PPV 90% (72-96.9 %).

CONCLUSION

Dynamic CT results an effective and highly sensitive diagnostic exam for children with tracheo-bronchomalacia. CT is especially indicated for those small and fragile patients that cannot undergo an invasive investigation. Moreover, CT allows a detailed evaluation both of the airways and the lungs which is useful for the clinical management.

Review of tracheobronchial foreign body aspiration in the South African paediatric age group

Children, and in particular young children under the age of three, are the most vulnerable for aspiration and ingestion of foreign bodies (FBs). The Red Cross War Memorial Children's Hospital in Cape Town is the only children's hospital in South Africa and is unique in having a dedicated trauma unit for children under the age of 13 as part of its institution. Core activities of Childsafe South Africa (CSA), located at the hospital, are data accumulation and interpretation, development of educational programmes, health inculcation and advising in legislation involving child health. To achieve this task, CSA works in close co-operation with government, industry, non-governmental and community predicated organisations, community groups and individuals. A database of all children treated for trauma at CSA has been maintained since 1991; it currently contains detailed information of over 170,000 injuries in children under the age of 13. This review consists of a literature review combined with data from our database and aims to provide information on our experiences with tracheobronchial aspiration of FBs in children.

The presentation and management of granulomatosis with polyangiitis (Wegener's Granulomatosis) in the pediatric airway

OBJECTIVE

Granulomatosis with polyangiitis (GPA) is a necrotizing inflammatory disease that can affect the airway. The purpose of this study was to present a case of pediatric laryngotracheal GPA and provide management recommendations based on a thorough review of the literature.

DATA SOURCES

Retrospective chart and literature review REVIEW METHODS: A pediatric patient with laryngotracheal and pulmonary manifestations of GPA who underwent chemotherapy and intralesional corticosteroid injection is described. An extensive literature review of pediatric GPA affecting the larynx/trachea was also performed.

RESULTS

A pediatric patient presented with acute respiratory distress. Flexible laryngoscopy revealed a laryngeal mass. Magnetic resonance imaging showed circumferential subglottic stenosis, and chest computed tomography demonstrated multiple pulmonary nodules. Laryngeal and tracheal biopsy revealed granulation tissue and primary vasculitis. Labs demonstrated positive cytoplasmic antineutrophil cytoplasmic antibody, consistent with GPA. Methylprednisone, rituximab, cyclophosphamide, and intralesional steroid injection resulted in remission after 12 weeks. Review of the literature revealed two pediatric cases series and 10 case reports of GPA affecting the larynx or trachea.

CONCLUSIONS

There is a higher prevalence of GPA of the airway in children when compared to adults. Biopsy of the airway lesion may not be necessary and has lower diagnostic yield compared to other GPA subsites. Medical management includes induction therapy followed by maintenance therapy once the disease is in remission. Most patients will require a surgical intervention to maintain the airway.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:233-240, 2017.

Primary lung and large airway neoplasms in children: current imaging evaluation with multidetector computed tomography

Multidetector computed tomography (MDCT) offers an important noninvasive imaging modality for confirmation and further characterization of primary lung and large airway neoplasms encountered in pediatric patients. Children represent a unique challenge in imaging, not only because of unique patient factors (eg, inability to follow instructions, motion, need for sedation) but because of the technical factors that must be optimized to reduce radiation dose. This article reviews an MDCT imaging algorithm, up-to-date imaging techniques, and clinical applications of MDCT for evaluating benign and malignant primary neoplasms of lung and large airway in infants and children.

Evaluation of pediatric thoracic disorders: comparison of unenhanced fast-imaging-sequence 1.5-T MRI and contrast-enhanced MDCT

OBJECTIVE

The purpose of this study was to investigate the efficacy of thoracic MRI with fast imaging sequences without contrast administration at 1.5 T for evaluating thoracic abnormalities by comparing MRI findings with contrast-enhanced MDCT findings.

SUBJECTS AND METHODS

A prospective study included consecutively registered pediatric patients who from December 2009 to January 2012 underwent thoracic MDCT followed within 2 days by MRI for evaluation of thoracic abnormalities. The final study sample consisted of 71 children (36 boys, 35 girls; mean age, 8.6 ± 4.5 years; range, 2 months-16 years) and 71 paired thoracic MRI and MDCT studies. Thoracic MRI was performed in the axial and coronal planes with the following fast imaging sequences: T1-weighted fast-field echo inversion prepulse, T2-weighted balanced fast-field echo multiple 2D, T1- and T2-weighted turbo spin-echo cardiac-triggering parallel imaging technique without cardiac monitoring, and STIR. Thoracic MDCT was performed with i.v. contrast administration. Two pediatric radiologists independently reviewed each MRI and MDCT study for abnormalities in the lung, large airways, and mediastinal, pleural, and musculoskeletal structures. The sensitivity, specificity, and overall accuracy of MRI were calculated. Interobserver agreement was measured with the kappa coefficient.

RESULTS

With MDCT as the reference standard, 51 of 71 (72%) patients had abnormal findings on MDCT studies, including infections in 21 (42%) cases, neoplasms in 19 (37%) cases, interstitial lung disease in seven (14%) cases, pleural effusion in three (6%) cases, and congenital bronchogenic cyst in one (2%) case. The overall diagnostic accuracy, sensitivity, and specificity of MRI for detecting thoracic abnormalities were 69 of 71 (97%), 49 of 51 (96%), and 20 of 20 (100%). Two undiagnosed findings with MRI that were detected with MDCT were mild bronchiectasis and small pulmonary nodule (3 mm). Almost perfect interobserver agreement was found between two reviewers with 70 of 71 agreements (κ = 0.97; 95% CI, 0.92-1.00; p < 0.001). CONCLUSION; MRI with fast imaging sequences without contrast administration is comparable to contrast-enhanced MDCT for detecting thoracic abnormalities in pediatric patients. Use of MRI with fast imaging sequences without contrast administration as a first-line cross-sectional imaging study in lieu of contrast-enhanced MDCT has the potential to benefit this patient population owing to reduced radiation exposure and i.v. contrast administration.

Evolution of acquired tracheobronchomalacia in an infant studied by multidetector computed tomography

Acquired tracheobronchomalacia (TBM) is an uncommon complication of severe lung disease in infancy. We report a case of TBM in an ex-premature infant with severe chronic lung disease (CLD). Multidetector computed tomography (MDCT) was used to dynamically assess the patency of the large airways at different time periods during the infant's hospital course. Initially at 3 months of age, the airways maintained patency during both phases of the respiratory cycle, but at 6 months of age, diffuse TBM was evident on MDCT. Appropriate management with long-term positive end expiratory pressure (PEEP) was initiated for the infant once the diagnosis of acquired TBM was confirmed. The case highlights the efficacy and relative ease of early diagnosis of acquired TBM by MDCT in infants at risk of this condition.

Advanced large airway CT imaging in children: evolution from axial to 4-D assessment

Continuing advances in multidetector computed tomography (MDCT) technology are revolutionizing the non-invasive evaluation of congenital and acquired large airway disorders in children. For example, the faster scanning time and increased anatomical coverage that are afforded by MDCT are especially beneficial to children. MDCT also provides high-quality multiplanar 2-dimensional (2-D), internal and external volume-rendering 3-dimensional (3-D), and dynamic 4-dimensional (4-D) imaging. These advances have enabled CT to become the primary non-invasive imaging modality of choice for the diagnosis, treatment planning, and follow-up evaluation of various large airway disorders in infants and children. It is thus essential for radiologists to be familiar with safe and effective techniques for performing MDCT and to be able to recognize the characteristic imaging appearances of large airway disorders affecting children.

Dynamic pulmonary CT of children

OBJECTIVE

Wide-detector CT allows simultaneous imaging of the entire airway and lungs in small children. Images acquired in multiple phases by continuous scanning during respiration are viewed dynamically, allowing more complete airway and pulmonary evaluation than possible with static protocols. The purpose of this study was to evaluate whether low-dose techniques can be applied to dynamic pulmonary CT of small children.

MATERIALS AND METHODS

The study included 24 infants and small children with persistent respiratory difficulty who underwent dynamic pulmonary CT (11 with IV contrast administration, 13 without contrast administration). No significant difference in patient age was present in the two groups. Continuous-mode wide-detector scans were obtained at 350-millisecond gantry rotation for a total of 1.4 seconds at 80 kVp. Some contrast-enhanced studies for simultaneous vascular and airway evaluation were performed at slightly greater tube current. The effective dose for each patient was calculated, and the Student t test was performed to compare effective dose measurements.

RESULTS

All studies were of diagnostic quality, frequently yielding critical information not available with other diagnostic tests. The mean effective dose for all patients was 1.7 (SD, 1.1) mSv. In the group who received contrast material, the mean effective dose was greater (1.9 [SD, 1.4] mSv) than in the group who did not receive contrast material (1.5 [SD, 0.7] mSv), but the difference was not significant (p = 0.4).

CONCLUSION

Wide-detector dynamic CT is ideal for evaluation of the airway and lungs in infants and small children with persistent respiratory distress. Effective doses are low, typically less than 2 mSv.