Lungs in infants and young children: improved thin-section CT with a noninvasive controlled-ventilation technique--initial experience

Novel Surface Topographic Assessment of Lung Volume and Pulmonary Function Tests in Idiopathic Scoliosis: A Preliminary Study

OBJECTIVE

Severe spinal deformity results in restrictive pulmonary disease from thoracic distortions and lung-volume limitations. Though spirometry and body plethysmography are widely accepted tests for pulmonary function tests (PFTs), they are time-consuming and require patient compliance. This study investigates whether surface topographic [surface topography (ST)] measurements of body volume difference (BVD) and torso volume difference between maximum inhale and exhale correlate to values determined on PFTs.

METHODS

This study included patients with idiopathic scoliosis and thoracic/thoracolumbar curves ≥40 degrees. Patients received ST scans, clinical examinations, and EOS biplanar radiographs on the same day. PFTs were performed within 3 months of ST/radiographic analysis. Univariate linear regression analysis was used to examine relationships between BVD, PFT values, and mean curves.

RESULTS

Sixteen patients (14.6 ± 2.2 y, 69% females) with idiopathic scoliosis and mean thoracic/thoracolumbar curves of 62 degrees ± 15˚ degrees (45 degrees to 93 degrees) were assessed. BVD displayed statistically high-positive positive correlations with forced vital capacity ( R = 0.863, P < 0.0001), forced expiratory volume in 1 second ( R = 0.870, P < 0.001), vital capacity ( R = 0.802, P < 0.0001), and TLC ( R = 0.831, P < 0.0001. Torso volume difference showed similarly high positive correlations to forced vital capacity, forced expiratory volume in 1 second, vital capacity, and TLC, but not residual volume. No correlations emerged between the mean thoracic/thoracolumbar curve and BVD or PFT values.

CONCLUSION

This study strongly endorses further investigation into ST scanning as an alternative to traditional PFTs for assessing pulmonary volumes. The noncontact and noninvasive nature of ST scanning presents a valuable alternative method for analyzing thoracic volume, particularly beneficial for patients unable to cooperate with standard PFTs.

LEVEL OF EVIDENCE

Level II-prognostic.

Childhood Interstitial Lung Disease: Imaging Guidelines and Recommendations

Childhood interstitial lung disease (ChILD) is an umbrella term encompassing a diverse group of diffuse lung diseases affecting infants and children. Although the timely and accurate diagnosis of ChILD is often challenging, it is optimally achieved through the multidisciplinary integration of imaging findings with clinical data, genetics, and potentially lung biopsy. This article reviews the definition and classification of ChILD; the role of imaging, pathology, and genetics in ChILD diagnosis; treatment options; and future goals. In addition, a practical approach to ChILD imaging based on the latest available research and the characteristic imaging appearance of ChILD entities are presented.

Childhood Interstitial (Diffuse) Lung Disease: Pattern Recognition Approach to Diagnosis in Infants

OBJECTIVE. The purpose of this article is to discuss imaging techniques and a pattern-based approach for diagnosing childhood interstitial (diffuse) lung diseases in infants. CONCLUSION. Childhood interstitial (diffuse) lung disease in infants consists of a heterogeneous group of disorders previously classified with clinical, radiologic, and pathologic features. By use of an imaging-guided algorithm, the assessment of lung volumes and the presence of ground-glass opacities or cysts can assist the radiologist in making an accurate and timely diagnosis.

Four-Dimensional Thoracic CT in Free-Breathing Children

In pediatric thoracic CT, respiratory motion is generally treated as a motion artifact degrading the image quality. Conversely, respiratory motion in the thorax can be used to answer important clinical questions, that cannot be assessed adequately via conventional static thoracic CT, by utilizing four-dimensional (4D) CT. However, clinical experiences of 4D thoracic CT are quite limited. In order to use 4D thoracic CT properly, imagers should understand imaging techniques, radiation dose optimization methods, and normal as well as typical abnormal imaging appearances. In this article, the imaging techniques of pediatric thoracic 4D CT are reviewed with an emphasis on radiation dose. In addition, several clinical applications of pediatric 4D thoracic CT are addressed in various thoracic functional abnormalities, including upper airway obstruction, tracheobronchomalacia, pulmonary air trapping, abnormal diaphragmatic motion, and tumor invasion. One may further explore the clinical usefulness of 4D thoracic CT in free-breathing children, which can enrich one's clinical practice.

Early follow-up of lung disease in infants with cystic fibrosis using the raised volume rapid thoracic compression technique and computed tomography during quiet breathing

BACKGROUND

Among the different techniques used to monitor lung disease progression in infants with CF diagnosed by Newborn screening (NBS), raised volume-rapid thoracic compression (RVRTC) remains a promising tool. However, the need of sedation and positive pressure ventilation considerably limits its clinical use. We recently described a semi-quantitative method to evaluate air trapping by chest tomography during quite breathing without sedation (CTqb score). This parameter is the radiological sign of airway obstruction and could be also used for lung disease follow-up in infants with CF. However, its discriminative power compared with RVRTC and correlation with lung function parameters are not known.

OBJECTIVES

To compare the discriminative powers of the CTqb score and RVRTC parameters and to determine their correlation during the first year of life of infants with CF.

METHODS

In this multicenter longitudinal study, infants with CF diagnosed by NBS underwent RVRTC and CT during quite breathing at 10 ± 4 weeks (n = 30) and then at 13 ± 1 months of age (n = 28).

RESULTS

All RVRTC parameters and the CTqb score remained stable between evaluations. The CTqb score showed a higher discriminative power than forced expiratory volume in 0.5 s (FEV_0.5 ; the main RVRTC parameter) at both visits (66% and 50% of abnormal values vs 30% and 28%, respectively). No correlation was found between CTqb score and_, the different RVRTC parameters or the plethysmographic functional residual capacity, indicating that they evaluate different aspect of CF lung disease.

Combined Electrocardiography- and Respiratory-Triggered CT of the Lung to Reduce Respiratory Misregistration Artifacts between Imaging Slabs in Free-Breathing Children: Initial Experience

Objective

Cardiac and respiratory motion artifacts degrade the image quality of lung CT in free-breathing children. The aim of this study was to evaluate the effect of combined electrocardiography (ECG) and respiratory triggering on respiratory misregistration artifacts on lung CT in free-breathing children.

Materials and Methods

In total, 15 children (median age 19 months, range 6 months–8 years; 7 boys), who underwent free-breathing ECG-triggered lung CT with and without respiratory-triggering were included. A pressure-sensing belt of a respiratory gating system was used to obtain the respiratory signal. The degree of respiratory misregistration artifacts between imaging slabs was graded on a 4-point scale (1, excellent image quality) on coronal and sagittal images and compared between ECG-triggered lung CT studies with and without respiratory triggering. A p value < 0.05 was considered significant.

Results

Lung CT with combined ECG and respiratory triggering showed significantly less respiratory misregistration artifacts than lung CT with ECG triggering only (1.1 ± 0.4 vs. 2.2 ± 1.0, p = 0.003).

Conclusion

Additional respiratory-triggering reduces respiratory misregistration artifacts on ECG-triggered lung CT in free-breathing children.

Functional and Radiographic Outcomes Following Growth-Sparing Management of Early-Onset Scoliosis

BACKGROUND

In this study, we sought to evaluate radiographic, functional, and quality-of-life outcomes of patients who have completed growth-sparing management of early-onset scoliosis.

METHODS

This prospective study involved patients with early-onset scoliosis who underwent growth-sparing treatment and either "final" fusion or observation for ≥2 years since the last lengthening procedure. Demographics, radiographic parameters, pulmonary function test (PFT) values, and scores of patient-reported assessments (Early-Onset Scoliosis Questionnaire [EOSQ] and Scoliosis Research Society [SRS]-30) were obtained. At the most recent follow-up, patients performed 2 additional functional outcome tests: step-activity monitoring and a treadmill exercise-tolerance test.

RESULTS

Twelve patients were evaluated as "graduates" of growth-sparing management of early-onset scoliosis (mean of 37 months since the most recent surgery). The major scoliosis curve measurement averaged 88° before treatment and 47° at the most recent follow-up. T1-S1 height increased from a mean of 22.3 cm to 34.7 cm and T1-T12 height, from 13.3 to 22.3 cm. At the most recent follow-up, the mean forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) as a percentage of the predicted volume were 52.1% and 55.3%, respectively, and were essentially unchanged from the earliest PFT that patients could perform (FEV1 = 53.8% of predicted and FVC = 53.5% of predicted). There was no difference between graduates and controls with respect to activity time or total steps in step-activity monitoring, and in the exercise-tolerance test, graduates walked at the same speed but at a higher heart rate and at a significantly higher (p <0.001) VO2 cost (rate of oxygen consumed per distance traveled). The EOSQ mean score was 102.2 of a possible 120 points, and the SRS mean score was 4.1 of a possible 5 points.

CONCLUSIONS

A realistic long-term goal for the management of early-onset scoliosis appears to be spine elongation and maintenance of pulmonary function at a level that is no less than the percentage of normal at initial presentation. Functional testing and patient-reported outcomes at a mean of 3 years from the last surgery suggest that activity levels were generally equal to those of controls but required greater physiologic demand. General health and physical function outcomes revealed continued impairment in these domains.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Spirometer guided chest imaging in children: It is worth the effort!

PURPOSE

Computed tomography (CT) and magnetic resonance imaging (MRI) scans are used to assess and monitor several pediatric lung diseases. It is well recognized that lung volume at the moment of acquisition has a major impact on the appearance of lung parenchyma and airways. Importantly, the sensitivity of chest CT and MRI to detect bronchiectasis and gas trapping is highly dependent on adequate volume control during the image acquisition. This paper describes a feasible method to obtain accurate control of lung volume during chest imaging in pediatric patients with lung disease.

PROCEDURE

A procedure to obtain maximal respiratory manoeuvres with spirometry guidance during image acquisition for CT and MRI is described. This procedure requires training of the subject, an MRI compatible spirometer and close collaboration between a lung function scientist and the radiographer. A good to excellent target volume level for the inspiratory or expiratory scan can be achieved in around 90% of children. An important condition for this success rate is the training of the subject, executed prior to each chest CT or MRI, and instructions by the lung function scientist during the chest CT.

CONCLUSION

Implementing lung volume guidance with a spirometer is an important and feasible step to standardize chest imaging and to optimize the diagnostic yield of chest CT and MRI in children with lung disease. Training and the collaborative effort by a lung function scientist and radiographer is the key factor for success of this procedure. Pediatr Pulmonol. 2017;52:48-56. © 2016 Wiley Periodicals, Inc.

Multimodality thoracic imaging of juvenile systemic sclerosis: emphasis on clinical correlation and high-resolution CT of pulmonary fibrosis

OBJECTIVE. Juvenile systemic sclerosis is a rare multisystem autoimmune disorder characterized by vasculopathy and multiorgan fibrosis. Cardiopulmonary complications are the leading cause of morbidity and mortality. Although pulmonary fibrosis is the complication that is most common and well described, cardiovascular and esophageal involvement may also be observed. In this article, common thoracic findings in juvenile systemic sclerosis will be discussed. We will focus on chest CT, including CT findings of pulmonary fibrosis and associated grading methods, as well as cardiac MRI and esophageal imaging. CONCLUSION. Radiologists play a pivotal role in the initial diagnosis and follow-up evaluation of pediatric patients with systemic sclerosis. Treatment decisions and prognostic assessment are directly related to imaging findings along with clinical evaluation.

Clinical features of childhood primary ciliary dyskinesia by genotype and ultrastructural phenotype

RATIONALE

The relationship between clinical phenotype of childhood primary ciliary dyskinesia (PCD) and ultrastructural defects and genotype is poorly defined.

OBJECTIVES

To delineate clinical features of childhood PCD and their associations with ultrastructural defects and genotype.

METHODS

A total of 118 participants younger than 19 years old with PCD were evaluated prospectively at six centers in North America using standardized procedures for diagnostic testing, spirometry, chest computed tomography, respiratory cultures, and clinical phenotyping.

MEASUREMENTS AND MAIN RESULTS

Clinical features included neonatal respiratory distress (82%), chronic cough (99%), and chronic nasal congestion (97%). There were no differences in clinical features or respiratory pathogens in subjects with outer dynein arm (ODA) defects (ODA alone; n = 54) and ODA plus inner dynein arm (IDA) defects (ODA + IDA; n = 18) versus subjects with IDA and central apparatus defects with microtubular disorganization (IDA/CA/MTD; n = 40). Median FEV1 was worse in the IDA/CA/MTD group (72% predicted) versus the combined ODA groups (92% predicted; P = 0.003). Median body mass index was lower in the IDA/CA/MTD group (46th percentile) versus the ODA groups (70th percentile; P = 0.003). For all 118 subjects, median number of lobes with bronchiectasis was three and alveolar consolidation was two. However, the 5- to 11-year-old IDA/CA/MTD group had more lobes of bronchiectasis (median, 5; P = 0.0008) and consolidation (median, 3; P = 0.0001) compared with the ODA groups (median, 3 and 2, respectively). Similar findings were observed when limited to participants with biallelic mutations.

CONCLUSIONS

Lung disease was heterogeneous across all ultrastructural and genotype groups, but worse in those with IDA/CA/MTD ultrastructural defects, most of whom had biallelic mutations in CCDC39 or CCDC40.

Changes in Pulmonary Function and Controlled Ventilation-High Resolution CT of Chest After Antibiotic Therapy in Infants and Young Children with Cystic Fibrosis

BACKGROUND

Infants with cystic fibrosis (CF) develop early progressive lung disease which may be asymptomatic. Infant pulmonary function tests (IPFT) and controlled ventilation-high resolution computed tomography (CV-HRCT) of chest can detect early asymptomatic lung disease. It is not well established that these objective measures can detect changes in lung disease after clinical interventions.

OBJECTIVE

The purpose of this study was to evaluate usefulness of IPFT and CV-HRCT to detect changes in lung disease after intravenous (IV) antibiotic therapy in infants with early CF-related lung disease.

STUDY DESIGN

IPFTs and CV-HRCT done before and after 2 weeks of IV antibiotics in infants at our institution over the last 12 years were compared. CV-HRCTs were compared using the modified Brody scoring system.

RESULTS

The sample included 21 infants, mean age 85.2 ± 47.6 weeks. Mean change in weight was 0.4 ± 0.38 kg (p = 0.001). Significant changes in IPFT included mean % predicted FEV(0.5) (+13.5 %, p = 0.043), mean %FEF(25-75) (+30.2 %, p = 0.008), mean %RV/TLC (-11.2 %, p = 0.008), and mean %FRC/TLC (-4.5 %, p = 0.001). Total Brody scores improved from a median of 10 to 5 (p < 0.001) as did mean scores for airway wall thickening (p = 0.050), air trapping (p < 0.001), and parenchymal opacities (p = 0.003).

CONCLUSION

IPFT and CV-HRCT can be used as objective measures of improvement in lung disease for infants with CF treated with antibiotics.

What did we learn from two decades of chest computed tomography in cystic fibrosis?

Despite our current treatment, many cystic fibrosis (CF) patients still show progressive bronchiectasis and small airways disease. Adequate detection and monitoring of progression of these structural abnormalities is needed to personalize treatment to the severity of CF lung disease of the patient. Chest computed tomography (CT) is the gold standard to diagnose and monitor bronchiectasis. Many studies have been done to validate the role of chest CT in CF and to improve the protocols. From these studies it became clear that for correct interpretation of the severity of bronchiectasis and small airways disease standardization of lung volume for the inspiratory and expiratory CT scan acquisition is needed. The risk related to the radiation exposure of a chest CT scan every second year is considered low. Automated and quantitative image analysis systems are developed to improve the reliability and sensitivity of assessments of structural lung changes in CF, particularly in early life. In this paper an overview is given of the lessons learned from two decades of monitoring CF lung disease using chest CT.

Computed Tomography Lung Volume Changes After Surgical Treatment for Early-Onset Scoliosis

STUDY DESIGN

Single-center review of prospectively collected data.

OBJECTIVES

To document anatomic lung volume and thoracic parameter changes in early-onset scoliosis patients undergoing rib-based (RB), or spine-based (SB) distraction surgical treatment who were too young to perform pulmonary function tests.

METHODS

Twenty patients undergoing growth-sparing treatment had computed tomography lung volumes (CTvol) determined by controlled-ventilation CT scanning preoperatively and at a mean of 2.7 years later under an institutional review board (IRB)-approved protocol. Twelve patients had non-congenital curves and 8 had congenital curves. Eleven patients had SB constructs and 9 had RB ones. Computed tomography lung volumes were correlated to T1-12 length, T6 coronal width, pelvic width, and curve magnitude, and were normalized by comparison with age standards and pelvic width.

RESULTS

All patients had increased CTvol at follow-up (RB 51%, SB 46%; p < .001). All increased T1-12 length from 128 mm (range, 39-160 mm) preoperatively to 154 mm (range, 61-216 mm) at follow-up. Both RB and SB gained 2.6 cm; this measurement was significant in RB (p < .001) owing to the shorter preoperative length. The T1-12 length correlated well with CTvol preoperatively (p = .002) and at follow-up (p = .007). The T6 width correlated best with CTvol (r = 0.76; p < .001 preoperatively and at follow-up). Main thoracic curves improved 21° in SB (preoperatively, 78°) versus 1.5° correction in RB (preoperatively, 60.2°). There was no correlation between curve magnitude and CTvol preoperatively or at follow-up. Follow-up CTvol percentile decreased in 10 patients, increased in 6, and was unchanged in 4. The T1-12 length was less than the fifth percentile in all patients preoperatively and increased in 9 patients at follow-up, whereas 11 remained at less than the fifth percentile.

CONCLUSIONS

The CTvol quantitates anatomic results of early-onset scoliosis growth-sparing surgery in patients too young for standard pulmonary function tests. Thoracic length and width correlate well with absolute CTvol and are possible surrogate measures. Curve magnitude and correction correlate poorly and assume less importance in outcome evaluation. Thoracic volume and length gains exceeded normal growth in about half of the patients.

Interstitial lung disease in children

PURPOSE OF REVIEW

There has been tremendous progress in the approach to childhood interstitial lung diseases (chILD), with particular recognition that interstitial lung disease (ILD) in infants is often distinct from the forms that occur in older children and adults. Diagnosis is challenging because of the rarity of ILD and the fact that the presenting symptoms of ILD often overlap those of common respiratory disorders. This review summarizes the newly published recommendations for diagnosis and management, and highlights the recent scientific advances in several specific forms of chILD.

RECENT FINDINGS

Clinical practice guidelines emphasize the role for chest computed tomography, genetic testing, and lung biopsy in the diagnostic evaluation of children with suspected ILD. Recent studies have better defined the characteristics and molecular understanding of several different forms of ILD, including neuroendocrine cell hyperplasia of infancy and ILD, due to mutations in genes affecting surfactant production and metabolism. Despite significant progress, definitive therapies are often lacking.

SUMMARY

chILD encompasses a collection of rare, diffuse lung diseases. Timely recognition of children with suspected ILD and initiation of appropriate diagnostic evaluations will facilitate medical management. Systematic approaches to clinical care and further studies are needed to improve the outcomes of children with these rare disorders.

Birth cohorts in asthma and allergic diseases: report of a NIAID/NHLBI/MeDALL joint workshop

Population-based birth cohorts on asthma and allergies increasingly provide new insights into the development and natural history of the diseases. More than 130 birth cohorts focusing on asthma and allergy have been initiated in the last 30 years. A National Institute of Allergy and Infectious Diseases; National Heart, Lung, and Blood Institute; Mechanisms of the Development of Allergy (MeDALL; Framework Programme 7 of the European Commission) joint workshop was held in Bethesda, Maryland, on September 11-12, 2012, with 3 objectives: (1) documenting the knowledge that asthma/allergy birth cohorts have provided, (2) identifying the knowledge gaps and inconsistencies, and (3) developing strategies for moving forward, including potential new study designs and the harmonization of existing asthma birth cohort data. The meeting was organized around the presentations of 5 distinct workgroups: (1) clinical phenotypes, (2) risk factors, (3) immune development of asthma and allergy, (4) pulmonary development, and (5) harmonization of existing birth cohorts. This article presents the workgroup reports and provides Web links (AsthmaBirthCohorts.niaid.nih.gov or www.medall-fp7.eu), where the reader will find tables describing the characteristics of the birth cohorts included in this report, the type of data collected at differing ages, and a selected bibliography provided by the participating birth cohorts.

An official American Thoracic Society clinical practice guideline: classification, evaluation, and management of childhood interstitial lung disease in infancy

BACKGROUND

There is growing recognition and understanding of the entities that cause interstitial lung disease (ILD) in infants. These entities are distinct from those that cause ILD in older children and adults.

METHODS

A multidisciplinary panel was convened to develop evidence-based guidelines on the classification, diagnosis, and management of ILD in children, focusing on neonates and infants under 2 years of age. Recommendations were formulated using a systematic approach. Outcomes considered important included the accuracy of the diagnostic evaluation, complications of delayed or incorrect diagnosis, psychosocial complications affecting the patient's or family's quality of life, and death.

RESULTS

No controlled clinical trials were identified. Therefore, observational evidence and clinical experience informed judgments. These guidelines: (1) describe the clinical characteristics of neonates and infants (<2 yr of age) with diffuse lung disease (DLD); (2) list the common causes of DLD that should be eliminated during the evaluation of neonates and infants with DLD; (3) recommend methods for further clinical investigation of the remaining infants, who are regarded as having "childhood ILD syndrome"; (4) describe a new pathologic classification scheme of DLD in infants; (5) outline supportive and continuing care; and (6) suggest areas for future research.

CONCLUSIONS

After common causes of DLD are excluded, neonates and infants with childhood ILD syndrome should be evaluated by a knowledgeable subspecialist. The evaluation may include echocardiography, controlled ventilation high-resolution computed tomography, infant pulmonary function testing, bronchoscopy with bronchoalveolar lavage, genetic testing, and/or lung biopsy. Preventive care, family education, and support are essential.

Image analysis for cystic fibrosis: computer-assisted airway wall and vessel measurements from low-dose, limited scan lung CT images

Cystic fibrosis (CF) is a life-limiting genetic disease that affects approximately 30,000 Americans. When compared to those of normal children, airways of infants and young children with CF have thicker walls and are more dilated in high-resolution computed tomographic (CT) imaging. In this study, we develop computer-assisted methods for assessment of airway and vessel dimensions from axial, limited scan CT lung images acquired at low pediatric radiation doses. Two methods (threshold- and model-based) were developed to automatically measure airway and vessel sizes for pairs identified by a user. These methods were evaluated on chest CT images from 16 pediatric patients (eight infants and eight children) with different stages of mild CF related lung disease. Results of threshold-based, corrected with regression analysis, and model-based approaches correlated well with both electronic caliper measurements made by experienced observers and spirometric measurements of lung function. While the model-based approach results correlated slightly better with the human measurements than those of the threshold method, a hybrid method, combining these two methods, resulted in the best results.

Interstitial lung disease in infants: new classification system, imaging technique, clinical presentation and imaging findings

Interstitial lung disease (ILD) is defined as a rare, heterogeneous group of parenchymal lung conditions that develop primarily because of underlying developmental or genetic disorders. Affected infants typically present with clinical syndromes characterized by dyspnea, tachypnea, crackles and hypoxemia. Until recently, the understanding of ILD in infants has been limited largely owing to a lack of evidence-based information of underlying pathogenesis, natural history, imaging findings and histopathological features. However, ILD in infants is now better understood and managed because of (1) advances in imaging methods that result in rapid and accurate detection, (2) improved thoracoscopic techniques for lung biopsy, (3) a consensus regarding the pathological criteria for these particular lung conditions and (4) a new classification system based on the underlying etiology of ILD. This article reviews the new classification system, imaging technique, clinical presentation and imaging findings of ILD in infants. Specialized knowledge of this new classification system in conjunction with recognition of characteristic imaging findings of ILD in infants has great potential for early and accurate diagnosis, which in turn can lead to optimal patient management.

Update of respiratory tract disease in children with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disease characterized by abnormal ciliary structure and function leading to impaired mucociliary clearance and chronic progressive sinopulmonary disease. Upper and lower respiratory tract manifestations are cardinal features of PCD. This review summarizes the current state of knowledge of respiratory tract disease in individuals with PCD and highlights the challenges in identifying and quantifying lung disease in very young children with PCD. No specific therapies are available to correct ciliary dysfunction in PCD. Treatment is not evidence based, and recommendations are largely extrapolated from cystic fibrosis and other conditions with impaired mucociliary clearance. There is a pressing need to develop and validate outcome measures, including patient-reported outcomes, that could be used to evaluate potential therapies in PCD. This review concludes with recommendations for clinical endpoints and outcome measures and a prioritized list of treatments to study in PCD clinical trials.

Volume-monitored chest CT: a simplified method for obtaining motion-free images near full inspiratory and end expiratory lung volumes

BACKGROUND

Lung inflation and respiratory motion during chest CT affect diagnostic accuracy and reproducibility.

OBJECTIVE

To describe a simple volume-monitored (VM) method for performing reproducible, motion-free full inspiratory and end expiratory chest CT examinations in children.

MATERIALS AND METHODS

Fifty-two children with cystic fibrosis (mean age 8.8 ± 2.2 years) underwent pulmonary function tests and inspiratory and expiratory VM-CT scans (1.25-mm slices, 80-120 kVp, 16-40 mAs) according to an IRB-approved protocol. The VM-CT technique utilizes instruction from a respiratory therapist, a portable spirometer and real-time documentation of lung volume on a computer. CT image quality was evaluated for achievement of targeted lung-volume levels and for respiratory motion.

RESULTS

Children achieved 95% of vital capacity during full inspiratory imaging. For end expiratory scans, 92% were at or below the child's end expiratory level. Two expiratory exams were judged to be at suboptimal volumes. Two inspiratory (4%) and three expiratory (6%) exams showed respiratory motion. Overall, 94% of scans were performed at optimal volumes without respiratory motion.

CONCLUSION

The VM-CT technique is a simple, feasible method in children as young as 4 years to achieve reproducible high-quality full inspiratory and end expiratory lung CT images.

Role of high-resolution computed tomography in the detection of early cystic fibrosis lung disease

High-resolution computed tomography (HRCT) has been demonstrated to be sensitive at detecting early lung disease in cystic fibrosis (CF), often before it is apparent clinically. There is emerging evidence that structural changes in the lung occur earlier in life than previously appreciated. Despite this, the role of HRCT in young children with CF has yet to be defined, principally because the repeated exposure of children to X-ray doses several multiples that of a standard chest X-ray raises the concern of the long-term risks of ionizing radiation. With the challenges of acquiring HRCT images in young children in mind, we review scanning protocols and settings specific to young children, and review the best available evidence that describes early structural lung disease in young children with CF. The role of CT scoring and quantitative measures of CF lung disease are reviewed. The challenge for the future is to develop techniques that provide clinically useful information at the lowest possible radiation risk.

Assessment and monitoring of cystic fibrosis lung disease in infants and young children

Chronic airway infection and inflammation are the hallmarks of cystic fibrosis (CF) lung disease. As these events occur early in life, it is critical to develop techniques for the assessment and monitoring of early-CF lung disease in infants and young children. In the last several years, there have been major advances in the development of imaging technology to assess structural damage in CF lung disease, noninvasive markers of CF airway inflammation and measurement of lung function in infants and young children with CF. In this article, we will review these advances and techniques, and discuss future directions for research and clinical applications.

Early lung disease in young children with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease in which ciliary dysfunction leads to chronic lung, sinus, and middle ear disease. PCD is often not diagnosed until late childhood due to its presumed rarity and the technical expertise necessary for diagnosis; as such, little is known about lung disease in young children with PCD. We report on 3 young children with PCD who had evidence of lung disease on infant pulmonary function testing, bronchoscopy, and/or computed tomography (CT) of the chest before 3 years of age.

Pediatric abdominal CT angiography

Advancing multidetector technology offers opportunities for improved vascular assessment in children. Much of what is available deals with thoracic and central nervous system applications, with very little written about abdominal applications. That said, many of the technical aspects are similar to computed tomography (CT) angiography in these regions and are worthy of reviewing, in addition to those unique considerations for abdominal CT angiography (CTA) in children. Familiarity with appropriate abdominal CTA for pediatric multidetector array CT will provide the same opportunities as CTA in other regions.

Controlled-ventilation volumetric CT scan in the evaluation of acquired pulmonary lobar emphysema: a case report

Acquired lobar emphysema (ALE), a clinical entity often associated with bronchopulmonary dysplasia (BPD) in premature infants, carries significant morbidity and mortality. Because of compression of adjacent lung tissue and poor response to medical therapy, patients may require surgical resection of the hyperinflated region of lung. The decision of proceed to surgery is often problematic, relying upon standard chest radiographs, ventilation-perfusion scans, and high resolution CT (HRCT) scans. We report the use of controlled volume HRCT with breath-holding at TLC and FRC in an infant with severe BPD and ALE. Using reconstruction software, we could estimate total lung volume as well as the volume of the lobe affected by ALE at both lung volumes, permitting the determination of the degree of air trapping. This is turn afforded us confirmatory data of the extent of the affected lung, justifying surgical removal.

Endpoints for clinical trials in young children with cystic fibrosis

The availability of sensitive, reproducible, and feasible outcome measures for quantifying lung disease in children with cystic fibrosis (CF) younger than 6 years is critical to the conduct of clinical trials in this important population. Historically, identifying and quantifying the presence of lung disease in very young children with CF was hampered by a lack of reproducible measures of lung function or lung pathology. Over the past 10 years, significant progress has led to physiologic, anatomic, and bronchoscopic measures that may serve as endpoints for future intervention trials. These endpoints include infant and preschool lung function testing, computed tomography of the chest, and bronchoalveolar lavage markers of inflammation and infection. Much progress has occurred in standardizing lung function testing, which is essential for multicenter collaboration. Pulmonary exacerbation has the potential to serve as a clinical endpoint; however, there is currently no standardized definition in children with CF younger than 6 years. Further development of these outcomes measures will enable clinical trials in the youngest CF population with the objective of improving long-term prognosis.

A Kindred of Children With Interstitial Lung Disease

BACKGROUND

Childhood interstitial lung disease (ILD) is a spectrum of diseases including many different rare lung conditions. We present a family with an unusual presentation of ILD in association with rheumatologic and immunologic abnormalities.

METHODS

Eight children with a common father were evaluated for evidence of lung disease in association with rheumatologic findings. All underwent routine history and physical examination, hematologic evaluation, and chest radiography and/or CT scan of the chest. Seven children underwent a more extensive immunologic evaluation. Those who were able underwent pulmonary function testing, and four children underwent lung biopsy.

RESULTS

Six of eight children with a common father were found to have radiographic findings consistent with ILD. These children also had evidence of autoimmune disease with joint symptoms, alopecia, rheumatoid factor production, and hypergammaglobulinemia. Open-lung biopsy in four children revealed a spectrum of pulmonary lymphoid proliferations ranging from reactive lymphoid hyperplasia to lymphoid interstitial pneumonia.

CONCLUSION

The findings of ILD and autoimmunity in a kindred of children suggest a novel genetic disorder of autosomal dominant pattern and variable penetrance. Although the precise pathogenesis remains unclear, these cases provide valuable insight into childhood ILD.

Imaging of the Chest in Cystic Fibrosis

In the last 2 decades significant strides have been made in the application of chest imaging modalities to assess cystic fibrosis (CF) lung disease. This article covers current chest imaging modalities. It discusses CT, the research modality most commonly used to assess lung disease in CF, new insights regarding CF lung disease, and future directions in research and clinical care.

Computed Tomography Reflects Lower Airway Inflammation and Tracks Changes in Early Cystic Fibrosis

RATIONALE

Detecting and tracking early cystic fibrosis (CF) lung disease are difficult due to lack of sensitive markers of airway dysfunction.

OBJECTIVES

The goals were to detect regional distribution of airway disease through high-resolution computed tomography, correlate abnormalities to lower airway inflammation/infection, and compare computed tomography findings before and after intravenous antibiotic therapy in children with CF younger than 4 years experiencing a pulmonary exacerbation.

METHODS

High-resolution computed tomography was performed in 17 children scheduled for bronchoscopy. The radiologist identified the lobes with the "greatest" and "least" disease based on computed tomography, and bronchoalveolar lavage was performed in these areas. In 13 subjects, imaging was repeated after antibiotic completion. Modified Brody scores were assigned by two radiologists.

MEASUREMENTS AND MAIN RESULTS

The lobe with greatest disease was predominantly localized to the right and had higher modified Brody scores, indicating more severe abnormalities (p < 0.01), compared with the lobe with least disease. The total modified Brody score (p < 0.01), hyperinflation subscore (p < 0.01), and bronchial dilatation/bronchiectasis subscore (p < 0.01) improved after antibiotics and intensified airway clearance. Interleukin-8 levels (p < 0.01) and % neutrophils (p = 0.04) were increased in the lobe with greatest disease compared with the lobe with least disease.

CONCLUSIONS

These results indicate that, in young children with CF experiencing a pulmonary exacerbation, computed tomography detects regional differences in airway inflammation, may be a sensitive outcome to evaluate therapeutic interventions, and identifies early lung disease as being more prominent on the right.

Detection of Air Trapping on Inspiratory and Expiratory Phase Images Obtained by 0.3-Second Cine CT in the Lungs of Free-Breathing Young Children

OBJECTIVE

The objective of our study was to evaluate whether 0.3-second cine CT can be used to detect air trapping in the lungs of young children.

SUBJECTS AND METHODS

In 30 children (mean age, 25 months), 0.3-second cine CT was performed at six levels during 3 seconds of quiet breathing. The study population was divided into an air trapping group (n = 24) and a no-air trapping group (n = 6). Lung density was measured at an abnormal area (with or without air trapping) and an adjacent normal area on inspiratory and expiratory phase images. Lung density differences between inspiration and expiration were calculated and compared in abnormal areas (with or without air trapping) and in normal areas. Their percentages were calculated and compared between the two groups. In addition, lung density differences between abnormal and adjacent normal areas were calculated and compared between the two groups.

RESULTS

Lung density differences between inspiration and expiration were smaller in areas with air trapping (mean +/- SD, -19 +/- 34 H) than in abnormal areas without air trapping (138 +/- 36 H) (p < 0.001) or in normal areas (111 +/- 49 H) (p < 0.001). Their percentages were smaller in the group with air trapping (-27% +/- 54%) than in the group with no air trapping (120% +/- 87%) (p < 0.001). In the group with air trapping, lung density differences were larger at the expiratory phase (260 +/- 77 H) than at the inspiratory phase (129 +/- 69 H) (p < 0.001), but did not change through the respiratory cycle in the group with no air trapping (p > 0.05).

CONCLUSION

Air trapping can be accurately detected in the lungs of free-breathing young children using 0.3-second cine CT.

Computed tomography dose and variability of airway dimension measurements: how low can we go?

BACKGROUND

Quantitative CT shows promise as an outcome measure for cystic fibrosis (CF) lung disease in infancy, but must be accomplished at a dose as low as reasonably achievable.

OBJECTIVE

To determine the feasibility of ultra-low-dose CT for quantitative measurements of airway dimensions.

MATERIALS AND METHODS

Two juvenile pigs were anesthetized and their lungs scanned at 25 cm H(2)O face-mask pressure in apnoea using beam currents of 5, 10, 20, 40 and 100 mAs. The lumen diameters and wall thicknesses of matched airways (n=22) at each dose were measured by two observers using validated software. Measurement variability at each dose was compared to that at 100 mAs (reference dose) for large and small airways (lumen diameter <2.5 mm).

RESULTS

Lowering CT dose (mAs) affected measurement variability for lumen diameter of small and large airways (P<0.001) and for wall thickness of small (P<0.001), but not large (P=0.63), airways. To obtain the same measurement variability at 5 mAs as at 100 mAs, four to six small airways or one to three large airways have to be measured and averaged.

CONCLUSION

Quantitative airway measurements are feasible on images obtained at as low as 5 mAs, but more airways need to be measured to compensate for greater measurement variability.

Preoperative assessment and follow-up of congenital abnormalities of the pulmonary arteries using CT and MRI

Congenital heart disease (CHD), including complex anomalies of the pulmonary arteries, are now earlier diagnosed and treated. Due to improvements in interventional and surgical therapy, the number of patients with the need for follow-up examinations is increasing. Pre- and postinterventional imaging should be done as gently as possible, avoiding invasive techniques if possible. With the technical improvement of multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI), both techniques are increasingly used for noninvasive assessment of the pulmonary vasculature in children with CHD. Knowledge of the most common diseases affecting the pulmonary vasculature and the kind of surgical and interventional procedures is essential for optimal imaging planning. This is especially important because interventions can be positively influenced by high-quality imaging. Therefore, the most common diseases and procedures are described and imaging modality of choice and important image findings are discussed.

Multislice computed tomography as an adjunct to the management of an in-stent stenosis in an infant with congenital heart disease: Imaging for the future

The case report demonstrates the value of multslice computed tomography for stent imaging and detection of an in-stent stenosis in an infant with pulmonary atresia and ventricular septal defect after stent placement in the right pulmonary artery after biventricular repair.

Assessment of in-stent stenosis in small children with congenital heart disease using multi-detector computed tomography: A validation study

OBJECTIVES

Our purpose was to investigate the diagnostic reliability of multi-detector computed tomography (MDCT) in assessing in-stent stenosis compared to digital angiography (DA) in small children.

BACKGROUND

Little is known about the feasibility of using MDCT to assess stents placed to treat children with congenital heart disease (CHD).

METHODS

Twenty-two children (median age [range], 2(3/4) [(1/2) to 12] years) with 42 transcatheter placed stents (median diameter: 7.2 [3.4-16.3] mm) in the pulmonary arteries (n = 36), aorta (2), PDA (1), and SVC (3) underwent both MDCT and DA due to suspected hemodynamic problems.

RESULTS

Independent "blinded" observers were able to measure stent and minimal luminal diameters in 115 out of 124 (93%) stent segments on MDCT and DA. The interobserver variability was low (mean difference: 0.5, SD 0.8 mm) with high correlation (r = 0.97; P < .0001). The percent stenosis by MDCT correlated well with DA (r = 0.89, P < .0001; mean error 2.7, SD 10.4%). For all grades of stenosis, the sensitivity and specificity for MDCT were 58% and 97%, respectively. At a threshold of approximately > or =20% stenosis sensitivity became >98%. All stent associated complications [fracture (4), vascular narrowings (11)] were diagnosed by MDCT. As the stent diameter increased, there was significantly reduced variability between MDCT and DA for in-stent stenosis (P < .0001).

CONCLUSION

In small children, MDCT is a feasible and promising method for assessing stent associated complications in the treatment of CHD. Cardiac surgeons and interventional cardiologists might rely on this imaging modality to plan specific interventions more precisely and to assess the results upon follow up.

Computed Tomography in the Evaluation of Cystic Fibrosis Lung Disease

The first report of computed tomography (CT) scanning to monitor cystic fibrosis (CF)-related lung disease was published in 1986. Further publications followed, but in general there was little interest in this technique until recently. Two factors in particular have led to this increased interest. First is an increasing realization that pulmonary function tests, long the mainstay of CF evaluation, often underestimate the presence and severity of mild and moderate lung disease. Second is the need for more sensitive outcome measures to assess new therapies. This had led to new interest and a series of important publications. The goal of this article is to present the current status of CT scanning in CF.

Comparison of quiet breathing and controlled ventilation in the high-resolution CT assessment of airway disease in infants with cystic fibrosis

BACKGROUND

Respiratory motion and low lung volumes limit the quality of HRCT examinations in infants and young children.

OBJECTIVE

To assess the effects of respiratory motion and lung inflation on the ability to diagnose airway abnormalities and air trapping (AT) using HRCT in infants with cystic fibrosis (CF).

MATERIALS AND METHODS

HRCT images of the lungs were obtained at four anatomical levels in 16 sedated children (age 2.4+/-1.1 years, mean+/-SD) with CF using controlled ventilation at full lung inflation (CVCT-I), at resting end exhalation (CVCT-E), and during quiet breathing (CT-B). Two blinded reviewers independently and then by consensus scored all images for the presence or absence of bronchiectasis (BE), bronchial wall thickening (BWT), and AT.

RESULTS

Of the 64 images evaluated, BE was identified in 19 (30%) of the CVCT-I images compared to 6 (9%) of the CVCT-E images (P=0.006) and 4 (6%) of the CT-B images (P=0.044). AT was seen in 29 (45%) of the CVCT-E images compared to 14 (22%) of the CVCT-I images (P=0.012) and 12 (19%) of the CT-B images (P=0.012). There were no significant differences in the detection of BWT among the three methods.

SUMMARY

In infants with CF, fully inflating the lung improved the ability to diagnose early BE, and obtaining motion-free images at end exhalation enhanced the detection of AT.

High-resolution computed tomography imaging of airway disease in infants with cystic fibrosis

RATIONALE

The development of early lung disease in patients with cystic fibrosis (CF) remains poorly defined.

OBJECTIVE

Determine whether asymptomatic infants with CF have evidence for changes in airway structure when assessed by high-resolution computed tomography, and whether airway structure correlates with airway function in this age group.

METHODS

Thirteen infants with CF (8-33 mo) and 13 control infants (7-25 mo) were evaluated. Airway wall and lumen areas were measured from three 1-mm-thick cross-sectional images obtained from upper, middle, and lower lobes during a respiratory pause with the lungs inflated to an airway pressure of 20 cm H2O. Lung tissue density was measured from images obtained during a respiratory pause at FRC. Forced expiratory flows were measured by the rapid thoracic compression technique in 11 infants with CF.

RESULTS

Airway wall area increased more per unit increase in airway size, whereas airway lumen area increased less per unit increase in airway size in the CF than in the control group. Among infants with CF, a greater ratio of wall to lumen area correlated with lower airway function. In addition, lung density at relaxed (passive) FRC was lower for infants with CF than for control infants (0.38 vs. 0.43 g/ml; p < 0.02).

CONCLUSIONS

Our results indicate that infants with CF have thickened airway walls, narrowed airway lumens, and air trapping, when assessed by high-resolution computed tomography, and measurements of airway structure correlated with airway function.

Dornase Alfa Reduces Air Trapping in Children With Mild Cystic Fibrosis Lung Disease

PURPOSES

To evaluate quantitative air trapping measurements in children with mild cystic fibrosis (CF) lung disease during a 1-year, double-blind, placebo-controlled, recombinant human deoxyribonuclease (rhDNase) [dornase alfa] intervention trial and compare results from quantitative air trapping with those from spirometry or visually scored high-resolution CT (HRCT) scans of the chest.

MATERIALS AND METHODS

Twenty-five children with CF randomized to either daily rhDNase or placebo aerosol were evaluated at baseline, and at 3 months and 12 months by spirometer-triggered HRCT and spirometry. Outcome variables were percentage of predicted FVC, FEV1, and forced expiratory flow, midexpiratory phase (FEF(25-75%)); total and subcomponent visual HRCT scores; and quantitative air trapping measurements derived from chest HRCT images.

RESULTS

At baseline, there were no statistical differences between groups in any of the variables used as an outcome. After 3 months of treatment, both groups had improvements in percentage of predicted FEV1 and FEF(25-75%), and total HRCT visual scores. In contrast, the rhDNase group had a 13% decrease in quantitative air trapping from baseline (severe air trapping [A3]), compared to an increase of 48% in the placebo group (p = 0.023). After 12 months, both groups had declines in percentage of predicted FVC and FEV1, but the rhDNase group retained improvements in percentage of predicted FEF(25-75%) and quantitative air trapping. The mucus plugging and total HRCT visual scores were also improved in the rhDNase group after 12 months of treatment, with and without significant differences between groups (p = 0.026 and p = 0.676). Quantitative air trapping (A3) remained improved in the rhDNase group (- 15.4%) and worsened in the placebo group (+61.3%) with nearly significant differences noted between groups (p = 0.053) after 12 months of treatment.

CONCLUSIONS

Quantitative air trapping is a more consistent sensitive outcome measure than either spirometry or total HRCT scores, and can discriminate differences in treatment effects in children with minimal CF lung disease.

Cystic fibrosis lung disease: genetic influences, microbial interactions, and radiological assessment

Cystic fibrosis (CF) is a multiorgan disease caused by mutation of the CF transmembrane conductance regulator (CFTR) gene. Obstructive lung disease is the predominant cause of morbidity and mortality; thus, most efforts to improve outcomes are directed toward slowing or halting lung-disease progression. Current therapies, such as mucolytics, airway clearance techniques, bronchodilators, and antibiotics, aim to suppress airway inflammation and the processes that stimulate it, namely, retention and infection of mucus plaques at the airway surface. New approaches to therapy that aim to ameliorate specific CFTR mutations or mutational classes by restoring normal expression or function are being investigated. Because of its sensitivity in detecting changes associated with early airway obstruction and regional lung disease, high-resolution CT (HRCT) complements pulmonary function testing in defining disease natural history and measuring response to both conventional and experimental therapies. In this review, perspectives on the genetics and microbiology of CF provide a context for understanding the increasing importance of HRCT and other imaging techniques in assessing CF therapies.

Inspiratory and expiratory CT lung density in infants and young children

BACKGROUND

There is a lack of information on normal inspiratory and expiratory CT lung density in infants.

OBJECTIVE

To describe normal regional CT lung density at end inspiratory and end expiratory lung volumes in children ages 0--5 years.

MATERIALS AND METHODS

Motionless HRCT images were obtained at 25 cm (inspiratory) and 0 cm (expiratory) water pressure at apical (top of arch) and basal (2 cm above diaphragm) levels in 16 sedated children (mean age 1.5 years) who underwent CT for reasons other than respiratory disease. Density was measured at anterior-posterior and medial-lateral locations at each level in each lung. The influence of level, location, and age was quantified using analysis of variance methods.

RESULTS

Lung density declined linearly in the first few years of life and thereafter approximated adult values. Beginning with the anterior-basal location, density at end inspiration (HU)=-835-(16 x age in years)+16 (if apical)+33 (if posterior)+23 (if medial)+14 (if lateral); standard error=38. At resting end exhalation =-616-(41 x age)+50 (if apical)+155 (if posterior)+74 (if medial)+46 (if lateral); standard error=68.

CONCLUSION

We provide an initial basis for employing lung densitometry in infants and young children at end inspiration and resting end exhalation lung volumes.

Imaging evolution of airway disorders in children

This article discusses and illustrates the insights gained from CT imaging of the lungs in infants and young children who do not have respiratory motion and at end-inspiratory and resting end-expiratory lung volumes using noninvasive controlled ventilation CT technique. The potential role of noninvasive controlled ventilation CT in developing quantitative measures of airway disease is highlighted and clinical examples demonstrating the use of the technique are shown.

High-resolution CT scanning: potential outcome measure

PURPOSE OF REVIEW

High-resolution CT (HRCT) imaging of the chest can provide both structural and functional lung analysis useful to evaluate initial and progressive cystic fibrosis (CF) lung disease. Chest HRCT scoring systems have been used to evaluate the extent and severity of CF specific airway and lung parenchymal disease. The purpose of this review is to summarize recent developments in HRCT and volumetric chest CT imaging, CF chest CT scoring systems, and review how HRCT/volumetric CT can provide useful outcome measures for future CF clinical research.

RECENT FINDINGS

Early manifestation of CF lung disease determined by chest CT/HRCT imaging in CF infants and children with mild disease include regional air trapping and bronchial wall thickness. The distribution of findings in more progressed CF lung disease are heterogeneous, and there appears to be a large amount of nonhomogeneity of progressive lung pathology. Recent CF studies have used new clinical CT parameters such as quantitative air trapping, quantitative airway measurements, and a composite CT/pulmonary function test (PFT) score, which appear to be promising new outcome measures that are more sensitive than global pulmonary function measurements or total chest CT scores in discriminating early or mild CF lung disease and treatment effects during clinical interventions.

SUMMARY

Chest HRCT and volumetric CT imaging can detect regional CF lung changes before changes in global pulmonary function measurements. Chest HRCT scoring has been used in descriptive studies defining CF lung disease severity, in longitudinal studies to define progression of disease, and in clinical intervention studies to evaluate treatment effects. In the last 2 years, CF CT research has evolved from solely using chest HRCT scoring systems to utilization of composite CT/PFT scores, quantitative airway and air trapping measurements, and the utilization of volumetric CT imaging to evaluate three-dimensional data sets in patients with CF lung disease.

Imaging Considerations: Interstitial Lung Disease in Children

This article provides a guide for the technique and interpretation of high-resolution chest CT of diffuse lung disease in children. Specific causes of diffuse lung disease in infants and children are reviewed as a guide to the interpretation of these images. New information, particularly the identification of surfactant protein mutations, is included. The idiopathic interstitial pneumonia classification, which is frequently applied to pediatric lung biopsy specimens, is also discussed.