The spectrum of structural abnormalities on CT scans from patients with CF with severe advanced lung disease

Bronchoscopy-guided antimicrobial therapy for cystic fibrosis

BACKGROUND

Early diagnosis and treatment of lower respiratory tract infections is the mainstay of management of lung disease in cystic fibrosis (CF). When sputum samples are unavailable, diagnosis relies mainly on cultures from oropharyngeal specimens; however, there are concerns about whether this approach is sensitive enough to identify lower respiratory organisms. Bronchoscopy and related procedures such as bronchoalveolar lavage (BAL) are invasive but allow the collection of lower respiratory specimens from non-sputum producers. Cultures of bronchoscopic specimens provide a higher yield of organisms compared to those from oropharyngeal specimens. Regular use of bronchoscopy and related procedures may increase the accuracy of diagnosis of lower respiratory tract infections and improve the selection of antimicrobials, which may lead to clinical benefits. This is an update of a previous review that was first published in 2013 and was updated in 2016 and in 2018.

OBJECTIVES

To evaluate the use of bronchoscopy-guided (also known as bronchoscopy-directed) antimicrobial therapy in the management of lung infection in adults and children with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched three registries of ongoing studies and the reference lists of relevant articles and reviews. The date of the most recent searches was 1 November 2023.

SELECTION CRITERIA

We included randomised controlled studies involving people of any age with CF that compared the outcomes of antimicrobial therapies guided by the results of bronchoscopy (and related procedures) versus those guided by any other type of sampling (e.g. cultures from sputum, throat swab and cough swab).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their risk of bias and extracted data. We contacted study investigators for further information when required. We assessed the certainty of the evidence using the GRADE criteria.

MAIN RESULTS

We included two studies in this updated review. One study enrolled 170 infants under six months of age who had been diagnosed with CF through newborn screening. Participants were followed until they were five years old, and data were available for 157 children. The study compared outcomes for pulmonary exacerbations following treatment directed by BAL versus standard treatment based on clinical features and oropharyngeal cultures. The second study enrolled 30 children with CF aged between five and 18 years and randomised participants to receive treatment based on microbiological results of BAL triggered by an increase in lung clearance index (LCI) of at least one unit above baseline or to receive standard treatment based on microbiological results of oropharyngeal samples collected when participants were symptomatic. We judged both studies to have a low risk of bias across most domains, although the risk of bias for allocation concealment and selective reporting was unclear in the smaller study. In the larger study, the statistical power to detect a significant difference in the prevalence of Pseudomonas aeruginosa was low because Pseudomonas aeruginosa isolation in BAL samples at five years of age in both groups were much lower than the expected rate that was used for the power calculation. We graded the certainty of evidence for the key outcomes as low, other than for high-resolution computed tomography scoring and cost-of-care analysis, which we graded as moderate certainty. Both studies reported similar outcomes, but meta-analysis was not possible due to different ways of measuring the outcomes and different indications for the use of BAL. Whether antimicrobial therapy is directed by the use of BAL or standard care may make little or no difference in lung function z scores after two years (n = 29) as measured by the change from baseline in LCI and forced expiratory volume in one second (FEV1) (low-certainty evidence). At five years, the larger study found little or no difference between groups in absolute FEV1 z score or forced vital capacity (FVC) (low-certainty evidence). BAL-directed therapy probably makes little or no difference to any measure of chest scores assessed by computed tomography (CT) scan at either two or five years (different measures used in the two studies; moderate-certainty evidence). BAL-directed therapy may make little or no difference in nutritional parameters or in the number of positive isolates of P aeruginosa per participant per year, but may lead to more hospitalisations per year (1 study, 157 participants; low-certainty evidence). There is probably no difference in average cost of care per participant (either for hospitalisations or total costs) at five years between BAL-directed therapy and standard care (1 study, 157 participants; moderate-certainty evidence). We found no difference in health-related quality of life between BAL-directed therapy and standard care at either two or five years, and the larger study found no difference in the number of isolates of Pseudomonas aeruginosa per child per year. The eradication rate following one or two courses of eradication treatment and the number of pulmonary exacerbations were comparable in the two groups. Mild adverse events, when reported, were generally well tolerated. The most common adverse event reported was transient worsening of cough after 29% of procedures. Significant clinical deterioration was documented during or within 24 hours of BAL in 4.8% of procedures.

AUTHORS' CONCLUSIONS

This review, limited to two well-designed randomised controlled studies, shows no evidence to support the routine use of BAL for the diagnosis and management of pulmonary infection in preschool children with CF compared to the standard practice of providing treatment based on results of oropharyngeal culture and clinical symptoms. No evidence is available for adults.

Elevated Prostaglandin E2 Synthesis Is Associated with Clinical and Radiological Disease Severity in Cystic Fibrosis

Background: Previous studies found high but very variable levels of tetranor-PGEM and PGDM (urine metabolites of prostaglandin (PG) E2 and PGD2, respectively) in persons with cystic fibrosis (pwCF). This study aims to assess the role of cyclooxygenase COX-1 and COX-2 genetic polymorphisms in PG production and of PG metabolites as potential markers of symptoms' severity and imaging findings. Methods: A total of 30 healthy subjects and 103 pwCF were included in this study. Clinical and radiological CF severity was evaluated using clinical scoring methods and chest computed tomography (CT), respectively. Urine metabolites were measured using liquid chromatography/tandem mass spectrometry. Variants in the COX-1 gene (PTGS1 639 C>A, PTGS1 762+14delA and COX-2 gene: PTGS2-899G>C (-765G>C) and PTGS2 (8473T>C) were also analyzed. Results: PGE-M and PGD-M urine concentrations were significantly higher in pwCF than in controls. There were also statistically significant differences between clinically mild and moderate disease and severe disease. Patients with bronchiectasis and/or air trapping had higher PGE-M levels than patients without these complications. The four polymorphisms did not associate with clinical severity, air trapping, bronchiectasis, or urinary PG levels. Conclusions: These results suggest that urinary PG level testing can be used as a biomarker of CF severity. COX genetic polymorphisms are not involved in the variability of PG production.

Airspace Diameter Map-A Quantitative Measurement of All Pulmonary Airspaces to Characterize Structural Lung Diseases

(1) Background: Stereological estimations significantly contributed to our understanding of lung anatomy and physiology. Taking stereology fully 3-dimensional facilitates the estimation of novel parameters. (2) Methods: We developed a protocol for the analysis of all airspaces of an entire lung. It includes (i) high-resolution synchrotron radiation-based X-ray tomographic microscopy, (ii) image segmentation using the free machine-learning tool Ilastik and ImageJ, and (iii) calculation of the airspace diameter distribution using a diameter map function. To evaluate the new pipeline, lungs from adult mice with cystic fibrosis (CF)-like lung disease (βENaC-transgenic mice) or mice with elastase-induced emphysema were compared to healthy controls. (3) Results: We were able to show the distribution of airspace diameters throughout the entire lung, as well as separately for the conducting airways and the gas exchange area. In the pathobiological context, we observed an irregular widening of parenchymal airspaces in mice with CF-like lung disease and elastase-induced emphysema. Comparable results were obtained when analyzing lungs imaged with μCT, sugges-ting that our pipeline is applicable to different kinds of imaging modalities. (4) Conclusions: We conclude that the airspace diameter map is well suited for a detailed analysis of unevenly distri-buted structural alterations in chronic muco-obstructive lung diseases such as cystic fibrosis and COPD.

Qualitative and quantitative evaluation of computed tomography changes in adults with cystic fibrosis treated with elexacaftor-tezacaftor-ivacaftor: a retrospective observational study

Introduction: The availability of highly effective triple cystic fibrosis transmembrane conductance regulator (CFTR) modulator combination therapy with elexacaftor-tezacaftor-ivacaftor (ETI) has improved pulmonary outcomes and quality of life of people with cystic fibrosis (pwCF). The aim of this study was to assess computed tomography (CT) changes under ETI visually with the Brody score and quantitatively with dedicated software, and to correlate CT measures with parameters of clinical response. Methods: Twenty two adult pwCF with two consecutive CT scans before and after ETI treatment initiation were retrospectively included. CT was assessed visually employing the Brody score and quantitatively by YACTA, a well-evaluated scientific software computing airway dimensions and lung parenchyma with wall percentage (WP), wall thickness (WT), lumen area (LA), bronchiectasis index (BI), lung volume and mean lung density (MLD) as parameters. Changes in CT metrics were evaluated and the visual and quantitative parameters were correlated with each other and with clinical changes in sweat chloride concentration, spirometry [percent predicted of forced expiratory volume in one second (ppFEV1)] and body mass index (BMI). Results: The mean (SD) Brody score improved with ETI [55 (12) vs. 38 (15); p < 0.001], incl. sub-scores for mucus plugging, peribronchial thickening, and parenchymal changes (all p < 0.001), but not for bronchiectasis (p = 0.281). Quantitatve WP (p < 0.001) and WT (p = 0.004) were reduced, conversely LA increased (p = 0.003), and BI improved (p = 0.012). Lung volume increased (p < 0.001), and MLD decreased (p < 0.001) through a reduction of ground glass opacity areas (p < 0.001). Changes of the Brody score correlated with those of quantitative parameters, exemplarily WT with the sub-score for mucus plugging (r = 0.730, p < 0.001) and peribronchial thickening (r = 0.552, p = 0.008). Changes of CT parameters correlated with those of clinical response parameters, in particular ppFEV1 with the Brody score (r = -0.606, p = 0.003) and with WT (r = -0.538, p = 0.010). Discussion: Morphological treatment response to ETI can be assessed using the Brody score as well as quantitative CT parameters. Changes in CT correlated with clinical improvements. The quantitative analysis with YACTA proved to be an objective, reproducible and simple method for monitoring lung disease, particularly with regard to future interventional clinical trials.

Recruited monocytes/macrophages drive pulmonary neutrophilic inflammation and irreversible lung tissue remodeling in cystic fibrosis

Persistent neutrophil-dominated lung inflammation contributes to lung damage in cystic fibrosis (CF). However, the mechanisms that drive persistent lung neutrophilia and tissue deterioration in CF are not well characterized. Starting from the observation that, in patients with CF, c-c motif chemokine receptor 2 (CCR2)⁺ monocytes/macrophages are abundant in the lungs, we investigate the interplay between monocytes/macrophages and neutrophils in perpetuating lung tissue damage in CF. Here we show that CCR2⁺ monocytes in murine CF lungs drive pathogenic transforming growth factor β (TGF-β) signaling and sustain a pro-inflammatory environment by facilitating neutrophil recruitment. Targeting CCR2 to lower the numbers of monocytes in CF lungs ameliorates neutrophil inflammation and pathogenic TGF-β signaling and prevents lung tissue damage. This study identifies CCR2⁺ monocytes as a neglected contributor to the pathogenesis of CF lung disease and as a therapeutic target for patients with CF, for whom lung hyperinflammation and tissue damage remain an issue despite recent advances in CF transmembrane conductance regulator (CFTR)-specific therapeutic agents.

Real-life efficacy and safety of elexacaftor/tezacaftor/ivacaftor on severe cystic fibrosis lung disease patients

Elexacaftor/tezacaftor/ivacaftor (ETI) is a cystic fibrosis (CF) transmembrane conductance regulator modulator, which has shown efficacy in CF patients (≥6 years) with ≥1 Phe508del mutation and a minimal function mutation. In October 2019, ETI became available on compassionate use basis for Dutch CF patients with severe lung disease. Our objective was to investigate safety and efficacy of ETI in this patient group in a real-life setting. A multicenter longitudinal observational study was conducted to examine changes in FEV1 , BMI, and adverse events at initiation and 1, 3, 6, and 12 months after starting ETI. The number of exacerbations was recorded in the 12 months before and the 12 months after ETI treatment. Patients eligible for compassionate use had a FEV1 <40% predicted. Wilcoxon signed-rank test analyzed changes over time. Twenty subjects were included and followed up for up to 12 months after starting ETI. Treatment was well tolerated with mild side effects reported, namely, rash (15%) and stomach ache (20%) with 80% resolving within 1 month. Mean absolute increase of FEV1 was 11.8/13.7% (p ≤ .001) and BMI was 0.49/1.87 kg/m2 (p < .001-0.02) after 1/12 months, respectively. In comparison to the number of exacerbations pretrial, there was a marked reduction in exacerbations after initiation. Our findings show long-term effects of treatment with ETI in patients with severe CF lung disease in a real-life setting. Treatment with ETI is associated with increased lung function and BMI, less exacerbations, and only mild side effects.

Lung structure and function on MRI in preterm born school children with and without BPD: A feasibility study

BACKGROUND AND OBJECTIVE

The most common respiratory complication of prematurity is bronchopulmonary dysplasia (BPD), leading to structural lung changes and impaired respiratory outcomes. However, also preterm children without BPD may show similar adverse respiratory outcomes. There is a need for a safe imaging modality for preterm children with and without BPD for disease severity assessment and risk stratification. Our objective was to develop a magnetic resonance imaging (MRI) protocol in preterm children with and without BPD at school age.

METHODS

Nine healthy volunteers (median age 11.6 [range: 8.8-12.8] years), 11 preterm children with BPD (11.0 [7.2-15.6] years), and 9 without BPD (11.1 [10.7-12.6] years) underwent MRI. Images were scored on hypo- and hyperintense abnormalities, bronchopathy, and architectural distortion. MRI data were correlated to spirometry. Ventilation and perfusion defects were analyzed using Fourier Decomposition (FD) MRI.

RESULTS

On MRI, children with BPD had higher %diseased lung (9.1 (interquartile range [IQR] 5.9-11.6)%) compared to preterm children without BPD (3.4 (IQR 2.5-5.4)%, p < 0.001) and healthy volunteers (0.4 (IQR 0.1-0.8)%, p < 0.001). %Diseased lung correlated negatively with %predicted FEV₁ (r = -0.40, p = 0.04), FEV₁ /FVC (r = -0.49, p = 0.009) and FEF₇₅ (r = -0.63, p < 0.001). Ventilation and perfusion defects on FD sequence corresponded to hypointense regions on expiratory MRI.

CONCLUSION

Chest MRI can identify structural and functional lung damage at school age in preterm children with and without BPD, showing a good correlation with spirometry. We propose MRI as a sensitive and safe imaging method (without ionizing radiation, contrast agents, or the use of anesthesia) for the long-term follow-up of preterm children.

State-of-the-art review of lung imaging in cystic fibrosis with recommendations for pulmonologists and radiologists from the "iMAging managEment of cySTic fibROsis" (MAESTRO) consortium

OBJECTIVE

Imaging represents an important noninvasive means to assess cystic fibrosis (CF) lung disease, which remains the main cause of morbidity and mortality in CF patients. While the development of new imaging techniques has revolutionised clinical practice, advances have posed diagnostic and monitoring challenges. The authors aim to summarise these challenges and make evidence-based recommendations regarding imaging assessment for both clinicians and radiologists.

STUDY DESIGN

A committee of 21 experts in CF from the 10 largest specialist centres in Italy was convened, including a radiologist and a pulmonologist from each centre, with the overall aim of developing clear and actionable recommendations for lung imaging in CF. An a priori threshold of at least 80% of the votes was required for acceptance of each statement of recommendation.

RESULTS

After a systematic review of the relevant literature, the committee convened to evaluate 167 articles. Following five RAND conferences, consensus statements were developed by an executive subcommittee. The entire consensus committee voted and approved 28 main statements.

CONCLUSIONS

There is a need for international guidelines regarding the appropriate timing and selection of imaging modality for patients with CF lung disease; timing and selection depends upon the clinical scenario, the patient's age, lung function and type of treatment. Despite its ubiquity, the use of the chest radiograph remains controversial. Both computed tomography and magnetic resonance imaging should be routinely used to monitor CF lung disease. Future studies should focus on imaging protocol harmonisation both for computed tomography and for magnetic resonance imaging. The introduction of artificial intelligence imaging analysis may further revolutionise clinical practice by providing fast and reliable quantitative outcomes to assess disease status. To date, there is no evidence supporting the use of lung ultrasound to monitor CF lung disease.

Deposition of Inhaled Levofloxacin in Cystic Fibrosis Lungs Assessed by Functional Respiratory Imaging

Pulmonary infections caused by Pseudomonas aeruginosa (PA) represent the leading cause of pulmonary morbidity in adults with cystic fibrosis (CF). In addition to tobramycin, colistin, and aztreonam, levofloxacin has been approved in Europe to treat PA infections. Nevertheless, no lung deposition data on inhaled levofloxacin are yet available. We conducted a Functional Respiratory Imaging (FRI) study to predict the lung deposition of levofloxacin in the lungs of patients with CF. Three-dimensional airway models were digitally reconstructed from twenty high-resolution computed tomography scans obtained from historical patients' records. Levofloxacin aerosols generated with the corresponding approved nebuliser were characterised according to pharmacopeia. The obtained data were used to inform a computational fluid dynamics simulation of levofloxacin lung deposition using breathing patterns averaged from actual CF patients' spirometry data. Levofloxacin deposition in the lung periphery was significantly reduced by breathing patterns with low inspiratory times and high inspiratory flow rates. The intrathoracic levofloxacin deposition percentages for moderate and mild CF lungs were, respectively, 37.0% ± 13.6 and 39.5% ± 12.9 of the nominal dose. A significant albeit modest correlation was found between the central-to-peripheral deposition (C/P) ratio of levofloxacin and FEV1. FRI analysis also detected structural differences between mild and moderate CF airways. FRI revealed a significant intrathoracic deposition of levofloxacin aerosols, which distributed preferentially to the lower lung lobes, with an influence of the deterioration of FEV1 on the C/P ratio. The three-dimensional rendering of CF airways also detected structural differences between the airways of patients with mild and moderate CF.

Structural lung disease following allergic bronchopulmonary aspergillosis complicating pediatric cystic fibrosis

BACKGROUND

Allergic bronchopulmonary aspergillosis (ABPA) complicating cystic fibrosis (CF) is frequently associated with significant structural lung damage as assessed by computed tomography (CT) scanning.

METHODS

Using a validated CF scoring system (structural lung disease [SLD] score) we examined the degree of structural lung disease in a group of 25 children with CF who had received steroid therapy for ABPA (CF-ABPA) and compared our findings to a matched group of CF patients without ABPA (CF-CON) using both cross-section and longitudinal analysis. Further, we examined the structure-function correlation between CT findings and lung function.

RESULTS

Mean SLD score (expressed as a percentage of maximal score) was significantly higher (worse) in the CF-ABPA group than the CF-CON group (29.3% CF-ABPA vs. 18.7% CF-CON p < .05). CF-ABPA patients showed significantly greater rate of development of structural lung disease over time than CF-CON patients (6.8% per year vs 1.4% p < .01). We found no correlation between lung function and the degree of structural lung disease.

CONCLUSIONS

ABPA in children with CF is associated with significantly more structural lung disease than that found in children with CF without ABPA. Despite interventive steroid therapy lung disease progresses more rapidly in those patients with ABPA and CF than control patients with CF.

Imaging in non-cystic fibrosis bronchiectasis and current limitations

Non-cystic fibrosis bronchiectasis represents a heterogenous spectrum of disorders characterised by an abnormal and permanent dilatation of the bronchial tree associated with respiratory symptoms. To date, diagnosis relies on computed tomography (CT) evidence of dilated airways. Nevertheless, definite radiological criteria and standardised CT protocols are still to be defined. Although largely used, current radiological scoring systems have shown substantial drawbacks, mostly failing to correlate morphological abnormalities with clinical and prognostic data. In limited cases, bronchiectasis morphology and distribution, along with associated CT features, enable radiologists to confidently suggest an underlying cause. Quantitative imaging analyses have shown a potential to overcome the limitations of the current radiological criteria, but their application is still limited to a research setting.

In the present review, we discuss the role of imaging and its current limitations in non-cystic fibrosis bronchiectasis. The potential of automatic quantitative approaches and artificial intelligence in such a context will be also mentioned.

Correlation of computed tomography findings and lung function in children and adolescents with cystic fibrosis

BACKGROUND

The timely and appropriate monitoring of pulmonary status is of utmost importance for patients with cystic fibrosis (CF). Computed tomography (CT) has been used in clinical and research settings for tracking lung involvement in CF patients. However, as CT delivers a considerable amount of radiation, its sequential use in CF patients remains a concern. The application of CT, therefore, should take into account its potential risks. This review aims to understand whether and to what extent the CT findings correlate with the findings from other monitoring tools in CF lung disease.

DATA SOURCES

PubMed was searched for articles about the correlation of chest CT findings with spirometric indices and with lung clearance index in children and adolescents with CF. The most relevant articles were reviewed and are presented herein.

RESULTS

Most studies have shown that forced expiratory volume in the first second (FEV₁) and other spirometric indices correlate moderately with CT structural lung damage. However, at the individual level, there were patients with FEV₁ within the normal range and abnormal CT and vice versa. Furthermore, longitudinal studies have indicated that the deterioration of structural lung damage does not occur in parallel with the progression of lung function. Lung clearance index is a better predictor of CT findings.

CONCLUSIONS

In general, the existing studies do not support the use of lung function tests as surrogates of chest CT.

Computed Tomographic Changes in Patients with Cystic Fibrosis Treated by Combination Therapy with Lumacaftor and Ivacaftor

Background: As Cystic Fibrosis (CF) treatments drastically improved in recent years, tools to assess their efficiency need to be properly evaluated, especially cross-sectional imaging techniques. High-resolution computed tomography (HRCT) scan response to combined lumacaftor- ivacaftor therapy (Orkambi^®) in patients with homozygous for F508del CFTR has not yet been assessed. Methods: We conducted a retrospective observational study in two French reference centers in CF in Marseille hospitals, including teenagers (>12 years old) and adults (>18 years) who had received lumacaftor–ivacaftor and for whom we had at disposal at least two CT scans, one at before therapy and one at least six months after therapy start. CT scoring was performed by using the modified version of the Brody score. Results: 34 patients have been included. The mean age was 26 years (12–56 years). There was a significant decrease in the total CT score (65.5 to 60.3, p = 0.049) and mucous plugging subscore (12.3 to 8.7, p = 0.009). Peribronchial wall thickening (PWT) was significantly improved only in the adult group (29.1 to 27.0, p = 0.04). Improvements in total score, peribronchial thickening, and mucous pluggings were significantly correlated with improvement in FEV1 (forced expiratory volume in 1 s). Conclusions: Treatment with lumacaftor–ivacaftor was associated with a significant improvement in the total CT score, which was mainly related to an improvement in mucous pluggings.

Congenital lung abnormality quantification by computed tomography: The CLAQ method

INTRODUCTION

To date, no consensus has been reached on the optimal management of congenital lung abnormalities, and factors predicting postnatal outcome have not been identified. We developed an objective quantitative computed tomography (CT) scoring method, and assessed its value for clinical decision-making.

METHODS

Volumetric CT-scans of all patients born with a congenital lung abnormality between January 1999 and 2018 were assessed. Lung disease was quantified using the newly-developed congenital lung abnormality quantification (CLAQ) scoring method. In 20 equidistant axial slices, cells of a square grid were scored according to the abnormality within. The scored CT parameters were used to predict development of symptoms, and SD scores for spirometry and exercise tolerance (Bruce treadmill test) at 8 years of age.

RESULTS

CT-scans of 124 patients with a median age of 5 months were scored. Clinical diagnoses included congenital pulmonary airway malformation (49%), bronchopulmonary sequestration (27%), congenital lobar overinflation (22%), and bronchogenic cyst (1%). Forty-four patients (35%) developed symptoms requiring surgery of whom 28 (22%) patients became symptomatic before a CT-scan was scheduled. Lesional hyperdensity was found as an important predictor of symptom development and decreased exercise tolerance. Using receiver operating characteristic analysis, an optimal cut-off value for developing symptoms was found at 18% total disease.

CONCLUSION

CT-quantification of congenital lung abnormalities using the CLAQ method is an objective and reproducible system to describe congenital lung abnormalities on chest CT. The risk for developing symptoms may increase when more than a single lung lobe is affected.

Designing Clinical Trials for Anti-Inflammatory Therapies in Cystic Fibrosis

The inflammatory response in the CF airway begins early in the disease process and becomes persistent through life in most patients. Inflammation, which is predominantly neutrophilic, worsens airway obstruction and plays a critical role in the development of structural lung damage. While cystic fibrosis transmembrane regulator modulators will likely have a dramatic impact on the trajectory of CF lung disease over the coming years, addressing other important aspects of lung disease such as inflammation will nevertheless remain a priority. Considering the central role of neutrophils and their products in the inflammatory response, potential therapies should ultimately affect neutrophils and their products. The ideal anti-inflammatory therapy would exert a dual effect on the pro-inflammatory and pro-resolution arms of the inflammatory cascade, both of which contribute to dysregulated inflammation in CF. This review outlines the key factors to be considered in the design of clinical trials evaluating anti-inflammatory therapies in CF. Important lessons have been learned from previous clinical trials in this area and choosing the right efficacy endpoints is key to the success of any anti-inflammatory drug development program. Identifying and validating non-invasive biomarkers, novel imaging techniques and sensitive lung function tests capable of monitoring disease activity and therapeutic response are important areas of research and will be useful for the design of future anti-inflammatory drug trials.

[Cystic fibrosis and computed tomography of the lungs]

With its high detail of morphological changes in lung parenchyma and airways as well as the possibilities for three-dimensional reconstruction, computed tomography (CT) represents a solid tool for the diagnosis and follow-up in patients suffering from cystic fibrosis (CF). Guidelines for standardized CT image acquisition in CF patients are still missing. In the mostly younger CF patients, an important issue is the well-considered use of radiation in CT imaging. The use of intravenous contrast agent is mainly restricted to acute emergency diagnostics. Typical morphological findings in CF lung disease are bronchiectasis, mucus plugging, or signs of decreased ventilation (air trapping) which can be detected with CT even in early stages. Various scoring systems that have become established over time are used to grade disease severity and for structured follow-up, e.g., in clinical research studies. With the technical development of CT, a number of postprocessing software tools were developed to help clinical reporting and overcome interreader differences for a standardized quantification. As an imaging modality free of ionizing radiation, magnetic resonance imaging (MRI) is becoming increasingly important in the diagnosis and follow-up of CF patients and is already frequently a substitute for CT for long-term follow-up at numerous specialized centers.

Will Airway Gene Therapy for Cystic Fibrosis Improve Lung Function? New Imaging Technologies Can Help Us Find Out

The promise of genetic therapies has turned into reality in recent years, with new first-line treatments for fatal diseases now available to patients. The development and testing of genetic therapies for respiratory diseases such as cystic fibrosis (CF) has also progressed. The addition of gene editing to the genetic agent toolbox, and its early success in other organ systems, suggests we will see rapid expansion of gene correction options for CF in the future. Although substantial progress has been made in creating techniques and genetic agents that can be highly effective for CF correction in vitro, physiologically relevant functional in vivo changes have been largely prevented by poor delivery efficiency within the lungs. Somewhat hidden from view, however, is the absence of reliable, accurate, detailed, and noninvasive outcome measures that can detect subtle disease and treatment effects in the lungs of humans or animal models. The ability to measure the fundamental function of the lung-ventilation, the effective transport of air throughout the lung-has been constrained by the available measurement technologies. Without sensitive measurement methods, it is difficult to quantify the effectiveness of genetic therapies for CF. The mainstays of lung health assessment are spirometry, which cannot provide adequate disease localization and is not sensitive enough to detect small early changes in disease; and computed tomography, which provides structural rather than functional information. Magnetic resonance imaging using hyperpolarized gases is increasingly useful for lung ventilation assessment, and it removes the radiation risk that accompanies X-ray methods. A new lung imaging technique, X-ray velocimetry, can now offer highly detailed regional lung ventilation information well suited to the diagnosis, treatment, and monitoring needs of CF lung disease, particularly after the application of genetic therapies. In this review, we discuss the options now available for imaging-based lung function measurement in the generation and use of genetic and other therapies for treating CF lung disease.

Predictive value of the modified Bhalla score for assessment of pulmonary exacerbations in adults with cystic fibrosis

OBJECTIVES

The objective of this study was to analyze the predictive value of the modified Bhalla score in high-resolution computed tomography (HRCT) for assessment of pulmonary exacerbations (PEx) in cystic fibrosis (CF) patients. We also describe the relationship between this score and pulmonary function test results.

METHODS

We performed a multicenter and prospective study where adult patients with CF were included consecutively over 18 months. All patients underwent HRCT with acquisition in inspiration and expiration. The results were analyzed by an expert radiologist who assigned a modified Bhalla score value. Lung function was also assessed, and clinical variables were collected. Follow-up lasted approximately 1 year, and PEx were registered.

RESULTS

The study population comprised 160 subjects selected from 360 CF patients monitored in the participating CF units. The mean age was 28 years, 47.5% were women, and mean forced expiratory volume in 1 s (FEV₁) was 67.5%. The mean global modified Bhalla score was 14.5 ± 0.31 points. Pulmonary function test (PFT) results and the modified Bhalla score correlated well, mainly forced vital capacity (FVC) and FEV₁. We constructed a statistical model based on the overall Bhalla score to predict the number of PEx.

CONCLUSIONS

The overall modified Bhalla score can predict future PEx in CF patients. This useful tool can help to prevent PEx in higher risk patients.

KEY POINTS

• Pulmonary function test results and the modified Bhalla score correlated well with FVC and FEV₁. • The total modified Bhalla score can predict the number of exacerbations in adult CF patients. • Our findings highlight the need to establish a unified protocol for chest HRCT during the follow-up of adult patients with CF in order to anticipate possible complications and determine their impact on pulmonary function.

Airway tapering: an objective image biomarker for bronchiectasis

Purpose

To estimate airway tapering in control subjects and to assess the usability of tapering as a bronchiectasis biomarker in paediatric populations.

Methods

Airway tapering values were semi-automatically quantified in 156 children with control CTs collected in the Normal Chest CT Study Group. Airway tapering as a biomarker for bronchiectasis was assessed on spirometer-guided inspiratory CTs from 12 patients with bronchiectasis and 12 age- and sex-matched controls. Semi-automatic image analysis software was used to quantify intra-branch tapering (reduction in airway diameter along the branch), inter-branch tapering (reduction in airway diameter before and after bifurcation) and airway-artery ratios on chest CTs. Biomarkers were further stratified in small, medium and large airways based on three equal groups of the accompanying vessel size.

Results

Control subjects showed intra-branch tapering of 1% and inter-branch tapering of 24–39%. Subjects with bronchiectasis showed significantly reduced intra-branch of 0.8% and inter-branch tapering of 19–32% and increased airway–artery ratios compared with controls (p < 0.01). Tapering measurements were significantly different between diseased and controls across all airway sizes. Difference in airway–artery ratio was only significant in small airways.

Conclusion

Paediatric normal values for airway tapering were established in control subjects. Tapering showed to be a promising biomarker for bronchiectasis as subjects with bronchiectasis show significantly less airway tapering across all airway sizes compared with controls. Detecting less tapering in larger airways could potentially lead to earlier diagnosis of bronchiectasis. Additionally, compared with the conventional airway–artery ratio, this novel biomarker has the advantage that it does not require pairing with pulmonary arteries.

Key Points

• Tapering is a promising objective image biomarker for bronchiectasis that can be extracted semi-automatically and has good correlation with validated visual scoring methods.

• Less airway tapering was observed in patients with bronchiectasis and can be observed sensitively throughout the bronchial tree, even in the more central airways.

• Tapering values seemed to be less influenced by variety in scanning protocols and lung volume making it a more robust biomarker for bronchiectasis detection.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06606-w) contains supplementary material, which is available to authorized users.

CF derived scoring systems do not fully describe the range of structural changes seen on CT scans in PCD

BACKGROUND

Structural lung changes seen on computed tomography (CT) scans in Cystic Fibrosis (CF) and Primary Ciliary Dyskinesia (PCD) are currently described using scoring systems derived from CF populations. This practise assumes lung damage in the two conditions is identical, potentially resulting in a failure to identify PCD-specific changes. Our study addresses this assumption.

METHODS

A total of 58 CT scans from 41 PCD patients (age 2-48 years) were examined and the presence and extent of abnormalities common in CF; bronchiectasis, bronchial wall thickening, atelectasis, mucous plugging, and air trapping noted. Further assessment of the PCD scans by an experienced chest radiologist identified several unique PCD specific changes.

RESULTS

Bronchial wall thickening was the commonest abnormality seen in PCD. All abnormalities were present more often in middle and lower lobes than in upper lobes (P < 0.001). Bronchiectasis, mucus plugging, atelectasis, and air trapping were present more often in PCD than in the historic CF cohorts which formed the basis of two CF scoring systems (P < 0.05). Extensive tree-in-bud pattern of mucus plugging, thickening of interlobar, and interlobular septa, and whole lobe atelectasis were seen significantly more frequently in PCD than CF.

CONCLUSIONS

Structural changes identified on CT scans in PCD are not identical to those previously described in CF patients and suggest assessment of PCD structural changes on CT should not use CF derived scoring systems.

Bronchoscopy-guided antimicrobial therapy for cystic fibrosis

BACKGROUND

Early diagnosis and treatment of lower respiratory tract infections are the mainstay of management of lung disease in cystic fibrosis. When sputum samples are unavailable, treatment relies mainly on cultures from oropharyngeal specimens; however, there are concerns regarding the sensitivity of these to identify lower respiratory organisms.Bronchoscopy and related procedures (including bronchoalveolar lavage) though invasive, allow the collection of lower respiratory specimens from non-sputum producers. Cultures of bronchoscopic specimens provide a higher yield of organisms compared to those from oropharyngeal specimens. Regular use of bronchoscopy and related procedures may help in a more accurate diagnosis of lower respiratory tract infections and guide the selection of antimicrobials, which may lead to clinical benefits.This is an update of a previous review.

OBJECTIVES

To evaluate the use of bronchoscopy-guided antimicrobial therapy in the management of lung infection in adults and children with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of latest search: 30 August 2018.We also searched three registries of ongoing studies and the reference lists of relevant articles and reviews. Date of latest search: 10 April 2018.

SELECTION CRITERIA

We included randomized controlled studies including people of any age with cystic fibrosis, comparing outcomes following therapies guided by the results of bronchoscopy (and related procedures) with outcomes following therapies guided by the results of any other type of sampling (including cultures from sputum, throat swab and cough swab).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their risk of bias and extracted data. We contacted study investigators for further information. The quality of the evidence was assessed using the GRADE criteria.

MAIN RESULTS

The search identified 11 studies, but we only included one study enrolling infants with cystic fibrosis under six months of age and diagnosed through newborn screening (170 enrolled); participants were followed until they were five years old (data from 157 children). The study compared outcomes following therapy directed by bronchoalveolar lavage for pulmonary exacerbations with standard treatment based on clinical features and oropharyngeal cultures.We considered this study to have a low risk of bias; however, the statistical power to detect a significant difference in the prevalence of Pseudomonas aeruginosa was limited due to the prevalence (of Pseudomonas aeruginosa isolation in bronchoalveolar lavage samples at five years age) being much lower in both the groups compared to that which was expected and which was used for the power calculation. The sample size was adequate to detect a difference in high-resolution computed tomography scoring. The quality of evidence for the key parameters was graded as low except high-resolution computed tomography scoring and cost of care analysis, which were graded as moderate quality.At five years of age, there was no clear benefit of bronchoalveolar lavage-directed therapy on lung function z scores or nutritional parameters. Evaluation of total and component high-resolution computed tomography scores showed no significant difference in evidence of structural lung disease in the two groups.In addition, this study did not show any difference between the number of isolates of Pseudomonas aeruginosa per child per year diagnosed in the bronchoalveolar lavage-directed therapy group compared to the standard therapy group. The eradication rate following one or two courses of eradication treatment was comparable in the two groups, as were the number of pulmonary exacerbations. However, the number of hospitalizations was significantly higher in the bronchoalveolar lavage-directed therapy group, but the mean duration of hospitalizations was significantly less compared to the standard therapy group.Mild adverse events were reported in a proportion of participants, but these were generally well-tolerated. The most common adverse event reported was transient worsening of cough after 29% of procedures. Significant clinical deterioration was documented during or within 24 hours of bronchoalveolar lavage in 4.8% of procedures.

AUTHORS' CONCLUSIONS

This review, limited to a single, well-designed randomized controlled study, shows no clear evidence to support the routine use of bronchoalveolar lavage for the diagnosis and management of pulmonary infection in pre-school children with cystic fibrosis compared to the standard practice of providing treatment based on results of oropharyngeal culture and clinical symptoms. No evidence was available for adult and adolescent populations.

Lung clearance index (LCI) as a predictor of exercise limitation among CF patients

INTRODUCTION

FEV₁ is often considered the gold standard to monitor lung disease in cystic fibrosis (CF). Recently, there has been increasing interest in multiple breath washout (MBW) and cardiopulmonary exercise testing (CPET) as alternative or even more sensitive techniques. However, limited data exist on associations among the above methods.

AIM

To evaluate the correlations between outcome measures of MBW and CPET and to examine if ventilation inhomogeneity can predict exercise intolerance.

SUBJECTS AND METHODS

Ninety-seven children and adults with CF (47 males, mean [range] age 14.9 (6.6; 26.7) years, mean FEV₁ : 90.8% predicted, mean lung clearance index [LCI]: 11.4, and mean peak oxygen uptake [VO₂ peak]: 82.4% predicted) performed spirometry, MBW, and CPET on the same day during their admission or outpatient visit.

RESULTS

LCI, m₁ /m₀ , and m₂ /m₀ (P < 0.001) as well as VO₂ peak%, breathing reserve (BR), minute ventilation (VE)/VO₂ (P < 0.001), and VE/carbon dioxide release (VCO₂ ) (P = 0.006) correlated significantly with FEV₁ %. LCI, m₁ /m₀ , and m₂ /m₀ correlated with VO₂ peak (P ≤ 0.001), VE (L/min) (P < 0.05), BR (P < 0.01), VE/VO₂ (P < 0.001), and VE/VCO₂ (P < 0.01). Multiple regression analysis showed that LCI could predict BR% (P < 0.001, r² :0.272) and VE/VO₂ (P < 0.001, r² : 0.207) while LCI and FRC could predict VO₂ peak% P < 0.001, r² : 0.216) and VE/VCO₂ (P < 0.001, r² : 0.226).

CONCLUSION

Ventilation inhomogeneity as indicated by increased LCI is associated with less efficient ventilation during strenuous exercise and negatively impacts exercise capacity in CF.

Air trapping in early cystic fibrosis lung disease-Does CT tell the full story?

INTRODUCTION

Mosaic attenuation on expiratory chest computed tomography (CT) is common in early life cystic fibrosis (CF) and often referred to as "air trapping". It is presumed to be localized hyperinflation due to small airway obstruction. In order to test this assumption, we compared air trapping extent to lung volumes measured on CT in young children with CF.

MATERIALS AND METHODS

Children aged below 7 years undergoing inspiratory/expiratory CT were recruited from the Australian Respiratory Early Surveillance Team for Cystic Fibrosis cohort. Automated lung segmentation was used to determine functional residual capacity (FRC), total lung capacity (TLC), and their ratio (FRC/TLC). Structural lung disease (%Disease) and air trapping (%TrappedAir) extent were assessed using PRAGMA-CF. Lung clearance index (LCI), an index of ventilation heterogeneity, was measured. Linear mixed model analysis was used to determine associations.

RESULTS

Seventy-three scans from 55 patients were obtained. %TrappedAir was associated with %Disease (0.19 [0.07, 0.31]; P = 0.003) and LCI (0.22 [0.04, 0.39]; P = 0.016), but not FRC/TLC (0.00 [-0.02, 0.02]; P = 0.931).

DISCUSSION

CT mosaic attenuation is associated with CF lung disease, however it is not always accompanied by physiologic hyperinflation. Other pathologies may contribute to mosaic attenuation. A better understanding of these factors could guide future therapies.

Diagnosis of bronchiectasis and airway wall thickening in children with cystic fibrosis: Objective airway-artery quantification

OBJECTIVES

To quantify airway and artery (AA)-dimensions in cystic fibrosis (CF) and control patients for objective CT diagnosis of bronchiectasis and airway wall thickness (AWT).

METHODS

Spirometer-guided inspiratory and expiratory CTs of 11 CF and 12 control patients were collected retrospectively. Airway pathways were annotated semi-automatically to reconstruct three-dimensional bronchial trees. All visible AA-pairs were measured perpendicular to the airway axis. Inner, outer and AWT (outer-inner) diameter were divided by the adjacent artery diameter to compute A_inA-, A_outA- and A_WTA-ratios. AA-ratios were predicted using mixed-effects models including disease status, lung volume, gender, height and age as covariates.

RESULTS

Demographics did not differ significantly between cohorts. Mean AA-pairs CF: 299 inspiratory; 82 expiratory.

CONTROLS

131 inspiratory; 58 expiratory. All ratios were significantly larger in inspiratory compared to expiratory CTs for both groups (p<0.001). A_outA- and A_WTA-ratios were larger in CF than in controls, independent of lung volume (p<0.01). Difference of A_outA- and A_WTA-ratios between patients with CF and controls increased significantly for every following airway generation (p<0.001).

CONCLUSION

Diagnosis of bronchiectasis is highly dependent on lung volume and more reliably diagnosed using outer airway diameter. Difference in bronchiectasis and AWT severity between the two cohorts increased with each airway generation.

KEY POINTS

• More peripheral airways are visible in CF patients compared to controls. • Structural lung changes in CF patients are greater with each airway generation. • Number of airways visualized on CT could quantify CF lung disease. • For objective airway disease quantification on CT, lung volume standardization is required.

Association between spirometry controlled chest CT scores using computer-animated biofeedback and clinical markers of lung disease in children with cystic fibrosis

Background: Computed tomography (CT) of the lungs is the gold standard for assessing the extent of structural changes in the lungs. Spirometry-controlled chest CT (SCCCT) has improved the usefulness of CT by standardising inspiratory and expiratory lung volumes during imaging. This was a single-centre cross-sectional study in children with cystic fibrosis (CF). Using SCCCT we wished to investigate the association between the quantity and extent of structural lung changes and pulmonary function outcomes, and prevalence of known CF lung pathogens.

Methods: CT images were analysed by CF-CT scoring (expressed as % of maximum score) to quantify different aspects of structural lung changes including bronchiectasis, airway wall thickening, mucus plugging, opacities, cysts, bullae and gas trapping. Clinical markers consisted of outcomes from pulmonary function tests, microbiological cultures from sputum and serological samples reflecting anti-bacterial and anti-fungal antibodies.

Results: Sixty-four children with CF, median age (range) of 12.7 (6.4–18.1) years, participated in the study. The median (range) CF-CT total score in all children was 9.3% (0.4–46.8) with gas trapping of 40.7% (3.7–100) as the most abundant finding. Significantly higher median CF-CT total scores (21.9%) were found in patients with chronic infections (N = 12) including Gram-negative infection and allergic bronchopulmonary aspergillosis (ABPA) exhibiting CF-CT total scores of 14.2% (ns) and 24.0% (p < 0.01), respectively, compared to 8.0% in patients with no chronic lung infection. Lung clearance index (LCI) derived from multiple breath washout exhibited closest association with total CF-CT scores, compared to other pulmonary function outcomes.

Conclusions: The most prominent structural lung change was gas trapping, while CF-CT total scores were generally low, both showing close association with LCI. Chronic lung infections, specifically in the form of ABPA, were associated with increased scores in lung changes. Further investigation of impact of infections with different microorganisms on extent and progression of structural CF lung disease is needed.

Spirometry-Assisted High Resolution Chest Computed Tomography in Children: Is it Worth the Effort?

BACKGROUND

Image quality of high resolution chest computed tomographies (HRCTs) depends on adequate breath holds at end inspiration and end expiration. We hypothesized that implementation of spirometry-assisted breath holds in children undergoing HRCTs would improve image quality over that obtained with voluntary breath holds by decreasing motion artifact and atelectasis.

METHODS

This is a retrospective case-control study of HRCTs obtained at a tertiary care children's hospital before and after implementation of a spirometry-assisted CT protocol, in which children ≥8 years of age are first trained in supine slow vital capacity maneuvers and then repeat the maneuvers in the CT scanner, coached by a respiratory therapist. Spirometry-assisted CT scans (cases) were matched by age, gender and diagnosis (cystic fibrosis vs other) to CT scans obtained with voluntary breath holds in the 6 years before implementation of the spirometry assistance protocol (controls), and evaluated by 2 blinded pediatric radiologists.

RESULTS

Among both cases and controls (N = 50 each), 10 carried the diagnosis of cystic fibrosis and 40 had other diagnoses. Mean age was 12.9 years (range: 7.5-20.1) among cases and 13.0 (7.1-19.7) among controls. Mean (SD) inspiratory image density among cases was -852 (37) Hounsfield units (HU) and -828 (43) among controls (p = 0.006). Mean (SD) expiratory image density was -629 (95) HU among cases and -688 (83) HU among controls (p = 0.002). Mean (SD) change in image density between inspiratory and expiratory images was +222 (85) HU among cases and +140 (76) HU among controls (p < 0.001). Motion artifact was present on inspiratory images in 5 cases and 9 controls (p = 0.39 by Fisher's exact test), and on expiratory images in 20 cases and 18 controls (p > 0.80). Atelectasis was present on inspiratory images in 8 cases and 9 controls and on expiratory images in 9 cases and 10 controls (p > 0.80).

CONCLUSIONS

Spirometry-assisted CTs had a significantly greater difference in lung density between inspiratory and expiratory scans than those performed with voluntary breath holds, likely improving the ability to detect air trapping. No appreciable difference in image quality was detected for the presence of motion artifact or atelectasis.

Chest imaging in cystic fibrosis studies: What counts, and can be counted?

BACKGROUND

The dawn of precision medicine and CFTR modulators require more detailed assessment of lung structure in cystic fibrosis (CF) clinical studies. Various imaging markers have emerged and are measurable, but clarity is needed to identify what markers should count for clinical studies. High-resolution chest computed tomography (CT) scoring has yielded sensitive markers for the study of CF disease progression. Once completed, CT scores from ongoing randomized controlled trials can be used to examine relationships between imaging endpoints and therapeutic effectiveness. Similarly, Magnetic Resonance Imaging (MRI) is in development to generate structural as well as functional markers.

RESULTS

The aim of this review is to characterize the role of currently available CT and MRI markers in clinical studies, and to discuss study design, data processing and statistical challenges unique to these endpoints in CF studies. Suggestions to overcome these challenges in CF studies are included.

CONCLUSIONS

To maximize the potential of CT and MRI markers in clinical studies and advance treatment of CF disease progression, efforts should be made to conduct longitudinal randomized controlled trials including these modalities, develop data repositories, promote standardization and conduct reproducible research.

Radiologic computed tomography features of Mycobacterium abscessus in cystic fibrosis

INTRODUCTION

Mycobacterium abscessus infection in cystic fibrosis (CF) patients can lead to poor outcomes. Early diagnosis is important, but there are no studies outlining specific imaging features of M. abscessus in CF.

OBJECTIVES

To describe the computed tomography (CT) findings of early M. abscessus infection in our CF population.

METHODS

Thirteen CF patients with sputum cultures positive for M. abscessus from 2006 to 2013 were identified at our institution. Clinical characteristics including culture dates and lung function were reviewed. Positive cultures were classified as "disease" versus "colonization" based on published criteria. Chest CT scans were reviewed at times closest to initial infection, and features including bronchiectasis, mucous plugging, consolidation, ground glass opacities, nodules, and cavitation were evaluated. Brody scores were calculated to evaluate extent of CF lung disease.

RESULTS

All patients had bronchiectasis and mucous plugging, with 10 of 13 (76.9%) in an upper lobe distribution. Consolidation was seen in 12 of 13 (92.3%) patients, 8 (61.5%) patients had nodules, and 5 (38.5%) with cavitation. The average Brody score was 59.5, which was no different than previously described CF cohorts without M. abscessus. There were no significant differences between subjects with disease versus colonization.

CONCLUSION

The most common CT features of early M. abscessus in our CF population include bronchiectasis, mucus plugging, and consolidation, but the findings did not reveal a unique radiologic signature. CT at this initial time point may not distinguish early M. abscessus infection from background lung disease or mycobacterial colonization in CF patients.

Objective airway artery dimensions compared to CT scoring methods assessing structural cystic fibrosis lung disease

Background

CF-CT and PRAGMA-CF are commonly used scoring methods to quantify the severity of bronchiectasis (BE) and airway wall thickening (AWT) on chest CTs of children with cystic fibrosis (CF). We aimed to validate CF-CT and PRAGMA-CF sub-scores for BE and AWT against quantitative airway–artery (AA) dimensions.

Methods

This is a retrospective study with 23 spirometer guided inspiratory chest CTs (11 CF, 12 controls; age range 6 to 16 years old) included. AA-, and AWTA-ratios of all visible AA pairs were computed by dividing diameters of the outer airway and wall (outer-inner airway) by the accompanying artery diameter, respectively. BE, AWT and total airway disease (TAD) were scored using CF-CT (% max score) and PRAGMA-CF (% extent). Correlations were computed using Spearman rank. Akaike information criterion (AIC) from the mixed-effects models were used to investigate whether CF-CT or PRAGMA-CF was a better predictor for AA-, and AWTA-ratios (lower AIC equals a better fitted model).

Results

4861 AA pairs were measured in total. Correlations between CF-CT and PRAGMA-CF: BE (r = 0.93, P < 0.001); AWT (r = 0.62, P < 0.001); TAD (r = 0.88, P < 0.001). PRAGMA-CF TAD sub-score had lowest AIC in the mixed-model predicting AA-ratio. CF-CT AWT and PRAGMA-CF TAD sub-score had equal low AIC in the mixed-model predicting AWTA-ratio.

Conclusion

PRAGMA-CF TAD sub-score was more precise predicting BE. CF-CT AWT and PRAGMA-CF TAD sub-scores predicted AWT equally well. CF-CT and PRAGMA-CF were both sensitive methods to score BE and AWT in children with CF lung disease, with PRAGMA-CT TAD sub-score being most accurate in predicting AA dimensions.

The development of bronchiectasis on chest computed tomography in children with cystic fibrosis: can pre-stages be identified?

Objective

Bronchiectasis is an important component of cystic fibrosis (CF) lung disease but little is known about its development. We aimed to study the development of bronchiectasis and identify determinants for rapid progression of bronchiectasis on chest CT.

Methods

Forty-three patients with CF with at least four consecutive biennial volumetric CTs were included. Areas with bronchiectasis on the most recent CT were marked as regions of interest (ROIs). These ROIs were generated on all preceding CTs using deformable image registration. Observers indicated whether: bronchiectasis, mucus plugging, airway wall thickening, atelectasis/consolidation or normal airways were present in the ROIs.

Results

We identified 362 ROIs on the most recent CT. In 187 (51.7 %) ROIs bronchiectasis was present on all preceding CTs, while 175 ROIs showed development of bronchiectasis. In 139/175 (79.4 %) no pre-stages of bronchiectasis were identified. In 36/175 (20.6 %) bronchiectatic airways the following pre-stages were identified: mucus plugging (17.7 %), airway wall thickening (1.7 %) or atelectasis/consolidation (1.1 %). Pancreatic insufficiency was more prevalent in the rapid progressors compared to the slow progressors (p = 0.05).

Conclusion

Most bronchiectatic airways developed within 2 years without visible pre-stages, underlining the treacherous nature of CF lung disease. Mucus plugging was the most frequent pre-stage.

Key Points

• Development of bronchiectasis in cystic fibrosis lung disease on CT.

• Most bronchiectatic airways developed within 2 years without pre-stages.

• The most frequently identified pre-stage was mucus plugging.

• This study underlines the treacherous nature of CF lung disease.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4329-z) contains supplementary material, which is available to authorized users.

Multicentre chest computed tomography standardisation in children and adolescents with cystic fibrosis: the way forward

Progressive cystic fibrosis (CF) lung disease is the main cause of mortality in CF patients. CF lung disease starts in early childhood. With current standards of care, respiratory function remains largely normal in children and more sensitive outcome measures are needed to monitor early CF lung disease. Chest CT is currently the most sensitive imaging modality to monitor pulmonary structural changes in children and adolescents with CF. To quantify structural lung disease reliably among multiple centres, standardisation of chest CT protocols is needed. SCIFI CF (Standardised Chest Imaging Framework for Interventions and Personalised Medicine in CF) was founded to characterise chest CT image quality and radiation doses among 16 participating European CF centres in 10 different countries. We aimed to optimise CT protocols in children and adolescents among several CF centres. A large variety was found in CT protocols, image quality and radiation dose usage among the centres. However, the performance of all CT scanners was found to be very similar, when taking spatial resolution and radiation dose into account. We conclude that multicentre standardisation of chest CT in children and adolescents with CF can be achieved for future clinical trials.

Bronchoscopy-guided antimicrobial therapy for cystic fibrosis

BACKGROUND

Early diagnosis and treatment of lower respiratory tract infections are the mainstay of management of lung disease in cystic fibrosis. When sputum samples are unavailable, treatment relies mainly on cultures from oropharyngeal specimens; however, there are concerns regarding the sensitivity of these to identify lower respiratory organisms.Bronchoscopy and related procedures (including bronchoalveolar lavage) though invasive, allow the collection of lower respiratory specimens from non-sputum producers. Cultures of bronchoscopic specimens provide a higher yield of organisms compared to those from oropharyngeal specimens. Regular use of bronchoscopy and related procedures may help in a more accurate diagnosis of lower respiratory tract infections and guide the selection of antimicrobials, which may lead to clinical benefits.This is an update of a previous review.

OBJECTIVES

To evaluate the use of bronchoscopy-guided antimicrobial therapy in the management of lung infection in adults and children with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched two registries of ongoing studies and the reference lists of relevant articles and reviews.Date of latest search: 28 August 2015.

SELECTION CRITERIA

We included randomized controlled studies including people of any age with cystic fibrosis, comparing outcomes following therapies guided by the results of bronchoscopy (and related procedures) with outcomes following therapies guided by the results of any other type of sampling (including cultures from sputum, throat swab and cough swab).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed their risk of bias and extracted data. We contacted study investigators for further information.

MAIN RESULTS

The search identified nine studies, but only one study with data from 157 participants (170 people were enrolled) was eligible for inclusion in the review. This study compared outcomes following therapy directed by bronchoalveolar lavage for pulmonary exacerbations during the first five years of life with standard treatment based on clinical features and oropharyngeal cultures. The study enrolled infants with CF who were under six months of age and diagnosed through newborn screening and followed them until they were five years old.We considered this study to have a low risk of bias; however, the statistical power to detect a significant difference in the prevalence of Pseudomonas aeruginosa was limited due to the prevalence (of Pseudomonas aeruginosa isolation in bronchoalveolar lavage samples at five years age) being much lower in both the groups compared to that which was expected and which was used for the power calculation. The sample size was adequate to detect a difference in high-resolution computed tomography scoring. The quality of evidence for the key parameters was graded as moderate except high-resolution computed tomography scoring and cost of care analysis, which were graded as high quality.At five years of age, there was no clear benefit of bronchoalveolar lavage-directed therapy on lung function z scores or nutritional parameters. Evaluation of total and component high-resolution computed tomography scores showed no significant difference in evidence of structural lung disease in the two groups.In addition, this study did not show any difference between the number of isolates of Pseudomonas aeruginosa per child per year diagnosed in the bronchoalveolar lavage-directed therapy group compared to the standard therapy group. The eradication rate following one or two courses of eradication treatment was comparable in the two groups, as were the number of pulmonary exacerbations. However, the number of hospitalizations was significantly higher in the bronchoalveolar lavage-directed therapy group, but the mean duration of hospitalizations was significantly less compared to the standard therapy group.Mild adverse events were reported in a proportion of participants, but these were generally well-tolerated. The most common adverse event reported was transient worsening of cough after 29% of procedures. Significant clinical deterioration was documented during or within 24 hours of bronchoalveolar lavage in 4.8% of procedures.

AUTHORS' CONCLUSIONS

This review, limited to a single, well designed randomized-controlled study, shows no clear evidence to support the routine use of bronchoalveolar lavage for the diagnosis and management of pulmonary infection in pre-school children with cystic fibrosis compared to the standard practice of providing treatment based on results of oropharyngeal culture and clinical symptoms. No evidence was available for adult and adolescent populations.

Validating chest MRI to detect and monitor cystic fibrosis lung disease in a pediatric cohort

BACKGROUND

Computed Tomography (CT) is the gold standard to assess bronchiectasis and trapped air in cystic fibrosis (CF) lung disease, but has the disadvantage of radiation exposure. Magnetic Resonance Imaging (MRI) is a radiation free alternative.

OBJECTIVE

To validate MRI as outcome measure by: correlating MRI scores for bronchiectasis and trapped air with clinical parameters, and by comparing those MRI scores with CT scores.

METHODS

In patients with CF (aged 5.6-17.4 years), MRI and CT were alternated annually during routine annual check-ups between July 2007 and January 2010. Twenty-three children had an MRI performed 1 year prior to CT, 34 children had a CT 1 year prior to MRI. Bronchiectasis and trapped air were scored using the CF-MRI and CF-CT scoring system. CF-MRI scores were correlated with clinical parameters: FEV1 , Pseudomonas aeruginosa, pulmonary exacerbations and patient-reported respiratory symptoms measured on the Cystic Fibrosis Questionnaire-Revised (CFQ-R), using Spearman's correlation coefficient. MRI and CT scores were compared using intra-class correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Fifty-seven patients who had an MRI, CT and CFQ-R during the study period were included. CF-MRI bronchiectasis correlated with FEV1 , Pseudomonas aeruginosa, pulmonary exacerbations and patient-reported respiratory symptoms. CF-MRI trapped air only correlated with FEV1 and Pseudomonas aeruginosa. ICCs between MRI and CT bronchiectasis and trapped air were 0.41 and 0.35 respectively. MRI tended to overestimate bronchiectasis compared to CT.

CONCLUSION

The associations between CF-MRI scores and several important clinical parameters further contributes to the validation of MRI. MRI provides different information than CT.

Pretransplant HRCT Characteristics Are Associated with Worse Outcome of Lung Transplantation for Cystic Fibrosis Patients

Objectives

Peri- and postoperative complications diminish the outcome of lung transplantation (LTx) in patients with cystic fibrosis (CF). We hypothesized that the degree of pathological findings on pre-LTx high resolution computed tomography (HRCT) is associated with higher morbidity and mortality in CF.

Methods

All our CF patients undergoing LTx between 2001 and 2011 were included. HRCT examinations were evaluated according to a scoring system for pulmonary disease in CF patients, the Severe Advanced Lung Disease (SALD) score and for pleural involvement.

Results

Fifty-three patients were included. Dominant infectious/inflammatory disease according to the SALD score was observed in 10 patients (19%). Five (50%) of those patients died within one week after LTx, compared to 2 (5%) patients without dominant infectious/inflammatory disease (p<0.001). This difference in survival percentage remained also significant in multivariate analysis. Patients with infectious/inflammatory disease received more packed red blood cells; 26 versus 8 in the first week (p<0.001). Pleural thickening was associated with higher requirement (10 units) for blood transfusion during LTx, compared to patients with normal pleura (4 units).

Conclusions

The analysis of HRCT in CF patients according to the SALD score showed that dominant infectious/inflammatory disease is associated with a higher mortality after LTx. If confirmed in other studies, HRCT might aid estimation of surgical risk in some adult CF patients.

Emphysema Is Common in Lungs of Cystic Fibrosis Lung Transplantation Patients: A Histopathological and Computed Tomography Study

Background

Lung disease in cystic fibrosis (CF) involves excessive inflammation, repetitive infections and development of bronchiectasis. Recently, literature on emphysema in CF has emerged, which might become an increasingly important disease component due to the increased life expectancy. The purpose of this study was to assess the presence and extent of emphysema in endstage CF lungs.

Methods

In explanted lungs of 20 CF patients emphysema was semi-quantitatively assessed on histology specimens. Also, emphysema was automatically quantified on pre-transplantation computed tomography (CT) using the percentage of voxels below -950 Houndfield Units and was visually scored on CT. The relation between emphysema extent, pre-transplantation lung function and age was determined.

Results

All CF patients showed emphysema on histological examination: 3/20 (15%) showed mild, 15/20 (75%) moderate and 2/20 (10%) severe emphysema, defined as 0–20% emphysema, 20–50% emphysema and >50% emphysema in residual lung tissue, respectively. Visually upper lobe bullous emphysema was identified in 13/20 and more diffuse non-bullous emphysema in 18/20. Histology showed a significant correlation to quantified CT emphysema (p = 0.03) and visual emphysema score (p = 0.001). CT and visual emphysema extent were positively correlated with age (p = 0.045 and p = 0.04, respectively).

Conclusions

In conclusion, this study both pathologically and radiologically confirms that emphysema is common in end-stage CF lungs, and is age related. Emphysema might become an increasingly important disease component in the aging CF population.

Assessment of CF lung disease using motion corrected PROPELLER MRI: a comparison with CT

OBJECTIVES

To date, PROPELLER MRI, a breathing-motion-insensitive technique, has not been assessed for cystic fibrosis (CF) lung disease. We compared this technique to CT for assessing CF lung disease in children and adults.

METHODS

Thirty-eight stable CF patients (median 21 years, range 6-51 years, 22 female) underwent MRI and CT on the same day. Study protocol included respiratory-triggered PROPELLER MRI and volumetric CT end-inspiratory and -expiratory acquisitions. Two observers scored the images using the CF-MRI and CF-CT systems. Scores were compared with intra-class correlation coefficient (ICC) and Bland-Altman plots. The sensitivity and specificity of MRI versus CT were calculated.

RESULTS

MRI sensitivity for detecting severe CF bronchiectasis was 0.33 (CI 0.09-0.57), while specificity was 100% (CI 0.88-1). ICCs for bronchiectasis and trapped air were as follows: MRI-bronchiectasis (0.79); CT-bronchiectasis (0.85); MRI-trapped air (0.51); CT-trapped air (0.87). Bland-Altman plots showed an MRI tendency to overestimate the severity of bronchiectasis in mild CF disease and underestimate bronchiectasis in severe disease.

CONCLUSIONS

Motion correction in PROPELLER MRI does not improve assessment of CF lung disease compared to CT. However, the good inter- and intra-observer agreement and the high specificity suggest that MRI might play a role in the short-term follow-up of CF lung disease (i.e. pulmonary exacerbations).

KEY POINTS

PROPELLER MRI does not match CT sensitivity to assess CF lung disease. PROPELLER MRI has lower sensitivity than CT to detect severe bronchiectasis. PROPELLER MRI has good to very good intra- and inter-observer variability. PROPELLER MRI can be used for short-term follow-up studies in CF.

Patient-specific modeling of regional antibiotic concentration levels in airways of patients with cystic fibrosis: are we dosing high enough?

Background

Pseudomonas aeruginosa (Pa) infection is an important contributor to the progression of cystic fibrosis (CF) lung disease. The cornerstone treatment for Pa infection is the use of inhaled antibiotics. However, there is substantial lung disease heterogeneity within and between patients that likely impacts deposition patterns of inhaled antibiotics. Therefore, this may result in airways below the minimal inhibitory concentration of the inhaled agent. Very little is known about antibiotic concentrations in small airways, in particular the effect of structural lung abnormalities. We therefore aimed to develop a patient-specific airway model to predict concentrations of inhaled antibiotics and to study the impact of structural lung changes and breathing profile on local concentrations in airways of patients with CF.

Methods

In- and expiratory CT-scans of children with CF (5–17 years) were scored (CF-CT score), segmented and reconstructed into 3D airway models. Computational fluid dynamic (CFD) simulations were performed on 40 airway models to predict local Aztreonam lysine for inhalation (AZLI) concentrations. Patient-specific lobar flow distribution and nebulization of 75 mg AZLI through a digital Pari eFlow model with mass median aerodynamic diameter range were used at the inlet of the airway model. AZLI concentrations for central and small airways were computed for different breathing patterns and airway surface liquid thicknesses.

Results

In most simulated conditions, concentrations in both central and small airways were well above the minimal inhibitory concentration. However, small airways in more diseased lobes were likely to receive suboptimal AZLI. Structural lung disease and increased tidal volumes, respiratory rates and larger particle sizes greatly reduced small airway concentrations.

Conclusions

CFD modeling showed that concentrations of inhaled antibiotic delivered to the small airways are highly patient specific and vary throughout the bronchial tree. These results suggest that anti-Pa treatment of especially the small airways can be improved.

Novel outcome measures for clinical trials in cystic fibrosis

Cystic fibrosis (CF) is a common inherited condition caused by mutations in the gene encoding the CF transmembrane regulator protein. With increased understanding of the molecular mechanisms underlying CF and the development of new therapies there comes the need to develop new outcome measures to assess the disease, its progression and response to treatment. As there are limitations to the current endpoints accepted for regulatory purposes, a workshop to discuss novel endpoints for clinical trials in CF was held in Anaheim, California in November 2011. The pros and cons of novel outcome measures with potential utility for evaluation of novel treatments in CF were critically evaluated. The highlights of the 2011 workshop and subsequent advances in technologies and techniques that could be used to inform the development of clinical trial endpoints are summarized in this review. Pediatr Pulmonol. © 2014 The Authors. Pediatric Pulmonology published by Wiley Periodicals, Inc.

Reversibility of trapped air on chest computed tomography in cystic fibrosis patients

PURPOSE

To investigate changes in trapped air volume and distribution over time and compare computed tomography (CT) with pulmonary function tests for determining trapped air.

METHODS

Thirty children contributed two CTs and pulmonary function tests over 2 years. Localized changes in trapped air on CT were assessed using image analysis software, by deforming the CT at timepoint 2 to match timepoint 1, and measuring the volume of stable (TAstable), disappeared (TAdisappeared) and new (TAnew) trapped air as a proportion of total lung volume. We used the difference between total lung capacity measured by plethysmography and helium dilution, residual volume to total lung capacity ratio, forced expiratory flow at 75% of vital capacity, and maximum mid-expiratory flow as pulmonary function test markers of trapped air. Statistical analysis included Wilcoxon's signed rank test and Spearman correlation coefficients.

RESULTS

Median (range) age at baseline was 11.9 (5-17) years. Median (range) of trapped air was 9.5 (2-33)% at timepoint 1 and 9.0 (0-25)% at timepoint 2 (p=0.49). Median (range) TAstable, TAdisappeared and TAnew were respectively 3.0 (0-12)%, 5.0 (1-22)% and 7.0 (0-20)%. Trapped air on CT correlated statistically significantly with all pulmonary function measures (p<0.01), other than residual volume to total lung capacity ratio (p=0.37).

CONCLUSION

Trapped air on CT did not significantly progress over 2 years, may have a substantial stable component, and is significantly correlated with pulmonary function markers.

Tracking CF disease progression with CT and respiratory symptoms in a cohort of children aged 6-19 years

INTRODUCTION

Cystic fibrosis (CF) lung disease is characterized by bronchiectasis and trapped air on chest computed tomography (CT).

OBJECTIVE

We aim to validate bronchiectasis and trapped air as outcome measures by evaluating associations between changes in bronchiectasis, trapped air and patient-reported respiratory symptoms.

METHODS

A longitudinal cohort study has been conducted. CF patients (aged 6-19 years) who had two routine CTs and completed twice a Cystic Fibrosis Questionnaire-Revised within 2 years (referred to as T1 and T2 ), in the period of July 2007 to January 2012 were included. Bronchiectasis and trapped air were scored using the CF-CT scoring system. Correlation coefficients and student's paired t tests were performed.

RESULTS

In total 40 patients were included with a median age at T1 of 12.6 years (range 6-17 years), and at T2 14.5 years (range 8-19 years). At T1 , bronchiectasis (r = -0.49, P < 0.01) and trapped air (r = -0.34, P = 0.04) correlated with CFQ-R Respiratory Symptoms Scores (CFQ-R RSS). At T2 similar correlations were found with the CFQ-R RSS. Over 2 years, there was significant progression in bronchiectasis (P = 0.03) and trapped air (P = 0.03), but not in CFQ-R RSS. Changes in bronchiectasis and trapped air were not associated with changes in CFQ-R RSS.

CONCLUSION

Our results indicate that bronchiectasis and trapped are sensitive outcome measures in CF lung disease, showing a significant association with CFQ-R RSS at two-time points. However, progression of bronchiectasis and trapped air over 2 year does not necessarily correlate to changes in quality of life.

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.

Scoring of chest CT in children with cystic fibrosis: state of the art

Chest CT has been proposed as a surrogate outcome measure in the evaluation of cystic fibrosis lung disease. Quantitative evaluation of chest CT findings requires application of a scoring system to derive numerical values. Several scoring systems are in use. These mostly rely on a subjective judgement of the severity and extent of various features of cystic fibrosis lung disease, including bronchiectasis, bronchial wall thickening, mucous plugging and air-trapping. Scores can subsequently be added to produce a total score. The precision or reproducibility of scoring systems has been assessed but with heterogeneous statistical approaches. Total scores appear to have high levels of reproducibility, but this might mask poorer levels of agreement for individual observations and component scores. It can also be questioned whether total scores are biologically meaningful, as compared to assessments of individual features. Various studies suggest that CT scores give an accurate indicator of the severity of disease, and CT scores might be the best predictors of long-term outcome, but data in this area are limited. CT scores are more sensitive than traditional lung-function indices such as FEV; however the lung clearance index, by multiple breath washout, appears to offer comparable sensitivity to CT. It is not clear whether CT scores are adequately responsive to changes in disease severity in the short to medium term; this is a challenge to the use of CT as a surrogate outcome measure for clinical trials of therapies specific to cystic fibrosis. Cystic fibrosis scoring would benefit from greater levels of standardisation in terms of CT techniques, scoring system, training of observers and measures of reproducibility. Automated approaches to quantifying CT parameters might also offer improved precision. The benefits of chest CT must be weighed against the principal drawback of radiation exposure. The case for more widespread use of chest CT would be strengthened if precision of CT scoring were improved.

Putting lung function and physiology into perspective: cystic fibrosis in adults

Adult cystic fibrosis (CF) is notable for the wide heterogeneity in severity of disease expression, both between patients and within the lungs of individuals. Although CF airways disease appears to start in the small airways, in adults there is typically widespread bronchiectasis, increased airway secretions, and extensive obstruction and inflammation of the small airways. The complexity and heterogeneity of airways disease in CF means that although there are many different methods of assessing and describing lung 'function', none of these single-dimensional tests is able to provide a comprehensive assessment of lung physiology across the spectrum seen in adult CF. The most widely described measure, the forced expiratory volume in 1 s, remains a useful and simple clinical tool, but is insensitive to early changes and may be dissociated from other more detailed assessments of disease severity such as computed tomography. In this review, we also discuss the use of more sensitive novel assessments such as multiple breath washout tests and impulse oscillometry, as well as the role of cardiopulmonary exercise testing. In the future, hyperpolarized gas magnetic resonance imaging techniques that combine regional structural and functional information may help us to better understand these measures, their applications and limitations.