Progressive damage on high resolution computed tomography despite stable lung function in cystic fibrosis

Searching for simple rules in Pseudomonas aeruginosa biofilm formation

OBJECTIVE

Living cells display complex and non-linear behaviors, especially when posed to environmental threats. Here, to understand the self-organizing cooperative behavior of a microorganism Pseudomonas aeruginosa, we developed a discrete spatiotemporal cellular automata model based on simple physical rules, similar to Conway's game of life.

RESULTS

The time evolution model simulations were experimentally verified for P. aeruginosa biofilm for both control and antibiotic azithromycin (AZM) treated condition. Our model suggests that AZM regulates the single cell motility, thereby resulting in delayed, but not abolished, biofilm formation. In addition, the model highlights the importance of reproduction by cell to cell interaction is key for biofilm formation. Overall, this work highlights another example where biological evolutionary complexity may be interpreted using rules taken from theoretical disciplines.

Noninvasive Multimodal Methods to Differentiate Inflamed vs Fibrotic Strictures in Patients With Crohn's Disease

Fibrotic strictures occur in 30% of patients with Crohn's disease (CD). However, there are no therapeutic agents that prevent or reverse fibrotic strictures. Strictures are treated by endoscopic dilatation procedures and surgical procedures, but there are high rates of recurrence. Two antifibrotic agents (nintedanib and pirfenidone) recently were approved for the treatment of idiopathic pulmonary fibrosis and inhibitors of Rho-associated protein kinases 1 and 2 reversed fibrosis in mice with chronic intestinal inflammation. Cross-sectional imaging techniques, such as magnetic resonance (MR) enterography, computed tomography enterography, and bowel ultrasound, are used to assess small-bowel and CD-related complications, including strictures. It is important to be able to determine the degree of inflammation and fibrosis in strictures to select the best therapy; this can be a challenge because inflammation and fibrosis co-exist to varying degrees in a damaged bowel segment. Delayed gadolinium enhancement, magnetization transfer MR imaging, and ultrasound elastography seem to be promising tools for assessing fibrosis in patients with CD. We review noninvasive techniques for fibrosis assessment, including analyses of genetic, epigenetic, and protein markers. We discuss the potential of imaging techniques such as diffusion-weighted and magnetization transfer MR imaging, strain elastography, shear-wave imaging, and positron emission tomography to guide therapeutic decisions for patients with stricturing CD.

Reduced exercise ventilatory efficiency in adults with cystic fibrosis and normal to moderately impaired lung function

Despite being a hallmark and an independent prognostic factor in several cardiopulmonary diseases, ventilatory efficiency-i.e., minute ventilation/carbon dioxide output relationship (V̇e/V̇co₂)-has never been systematically explored in cystic fibrosis (CF). To provide a comprehensive frame of reference regarding measures of ventilatory efficiency in CF adults with normal to moderately impaired lung function and to confirm the hypothesis that V̇e/V̇co₂ is a sensitive marker of early lung disease. CF patients were divided into three groups, according to their spirometry: normal (G₁), mild impairment (G₂), and moderate impairment (G₃) in lung function. All participants underwent incremental cardiopulmonary exercise testing on a cycle ergometer. Lowest V̇e/V̇co₂ ratio (nadir) and the slope and the intercept of the linear region of the V̇e/V̇co₂ relationship were contrasted in a two-center retrospective analysis, involving 72 CF patients and 36 healthy controls (HC). Compared with HC, CF patients had significantly higher V̇e/V̇co₂ nadir, slope, and intercept (P < 0.001, P < 0.001, and P = 0.049, respectively). Subgroup analysis revealed significant differences in nadir (P = 0.001) and slope (P = 0.012) values even between HC and G₁. Dynamic hyperinflation related negatively with slope (P = 0.045) and positively with intercept (P = 0.001), while no impact on nadir was observed. Ventilatory inefficiency is a clear feature of adults with CF, even among patients with normal spirometry. V̇e/V̇co₂ nadir seems to be the most reliable metric to describe ventilatory efficiency in CF adults. Further prospective studies are needed to clarify whether V̇e/V̇co₂ could represent a useful marker in the evaluation of early lung disease in CF.NEW & NOTEWORTHY This is the first study to investigate ventilatory efficiency in a cohort of adult cystic fibrosis (CF) patients with nonsevere lung disease. The finding of impaired ventilatory efficiency in patients with normal lung function confirms the higher sensitivity of exercise testing in detecting early lung disease compared with spirometry. Dynamic hyperinflation plays a significant role in determining the behavior of V̇e/V̇co₂ slope and intercept values with increasing lung function impairment. Apparently free from interference from mechanical constraints, V̇e/V̇co₂ nadir seems the most reliable parameter to evaluate ventilatory efficiency in CF adults.

Quantitative multivolume proton-magnetic resonance imaging in patients with cystic fibrosis lung disease: comparison with clinical indicators

This cross-sectional study aims to verify the relationship between quantitative multivolume proton-magnetic resonance imaging (¹H-MRI) and clinical indicators of ventilatory abnormalities in cystic fibrosis (CF) lung disease.Non-enhanced chest MRI, spirometry and multiple breath washout was performed by 28 patients (10-27 years) with CF lung disease. Images acquired at end-inspiration and end-expiration were registered by optical flow to estimate expiratory-inspiratory proton-density change (Δ¹H-MRI) as a measure of regional ventilation. Magnetic resonance images were also evaluated using a CF-specific scoring system.Biomarkers of CF ventilation impairment were defined from the Δ¹H-MRI as follows: Δ¹H-MRI median, Δ¹H-MRI quartile coefficient of variation (QCV) and percentage of low-ventilation volume (%LVV). Imaging biomarkers correlated to all the clinical measures of ventilation abnormality, with the strongest correlation between Δ¹H-MRI median and forced expiratory volume in 1 s (r²=0.44, p<0.001), Δ¹H-MRI QCV and lung clearance index (LCI) (r²=0.51, p<0.001) and %LVV and LCI (r²=0.66, p<0.001). Correlations were also found between imaging biomarkers of ventilation and morphological scoring.The study showed a significant correlation between quantitative multivolume MRI and clinical indicators of CF lung disease. MRI, as a non-ionising imaging technique, may be particularly attractive in CF care for longitudinal evaluation, providing a new imaging biomarker to detect early ventilatory abnormalities.

Applications of lung clearance index in monitoring children with cystic fibrosis

A sensitive, reproducible and feasible measure of lung function for monitoring the respiratory health is a prerequisite for the optimization of management of the patients with cystic fibrosis (CF). Spirometry has been considered the method of choice, although it is applicable only in children older than 6 years of age, as good cooperation is necessary for its proper performance. However, over the last 15 years, scientific interest in gas dilution techniques and particularly in multiple breath wash out (MBW) method has been revived. The most commonly reported index of MBW is lung clearance index (LCI). The aim of this review is to present the most recent developments in the application of LCI as a monitoring index of respiratory status of CF patients. LCI is a sensitive and reproducible marker of ventilation inhomogeneity. It is more sensitive than spirometry and, unlike spirometry; it can be performed across the whole pediatric age range. Since it is dependent on body size, until at least the age of 6 years, the relative and not the absolute changes are more appropriate for providing clinically meaningful conclusion on ventilation inhomogeneity. Until now, MBW has been mainly used as a research tool. Based on the currently available data LCI cannot safely predict high-resolution computed tomography findings in children with CF, especially in infants. It can be used as an end-point measure for the assessment of beneficial effect of interventions. However, its utility as an outcome measure for the efficacy of therapeutic interventions seems to be dependent on the pathophysiologic mechanisms that underlie each intervention. It seems that more studies, especially longitudinal ones, are required in order to fully clarify the clinical usefulness of LCI, not only in the research setting, but also in every day practice of CF clinic.

Evaluation of high resolution computed tomography findings of cystic fibrosis

BACKGROUND/AIMS

Morphological changes due to lung disease in patients with cystic fibrosis (CF) were evaluated using high resolution computed tomography (HRCT), and the HRCT scores obtained using the Bhalla scoring system were correlated with those obtained using clinical and laboratory indicators.

METHODS

Medical records of 28 children with CF who underwent chest CT in Department of Pediatric Allergy and Immunology, Cukurova University Balcali Hospital between March 2011 and January 2016 were retrospectively reviewed. Demographic data and physical examination, respiratory cultures, pulmonary function tests, and chest HRCT findings were evaluated. Patients were divided into the following two groups according to their forced expiratory volume in the first second (FEV1) values: normal FEV1 (≥ 80% of predicted values) and low FEV1 (< 80% of predicted values). Deep throat or sputum cultures were evaluated for the presence of Pseudomonas aeruginosa (PsA) and other bacteria. HRCT scans were scored using the Bhalla scoring system.

RESULTS

No significant correlation was found between the Bhalla scores and sex, age group, or height percentiles. Significant relationships were found between the Bhalla score and weight (p = 0.036) and body mass index (BMI) (p = 0.032) percentiles below the third percentile, bacterial growth in the sputum/ deep throat cultures (p = 0.009), and presence of PsA (p = 0.004). Moreover, a significant correlation was found between the Bhalla score and FEV1 (r = -0.315, p = 0.0272), forced vital capacity (FVC; r = -0.381, p = 0.0178), forced expiratory flow between 25% and 75% of FVC (r = -0.229, p = 0.0431), and BMI (r = -3.368, p = 0.050).

CONCLUSION

Chest HRCT is an important diagnostic tool for the pulmonary evaluation of children with CF.

Quantitative chest computerized tomography and FEV1 equally identify pulmonary exacerbation risk in children with cystic fibrosis

BACKGROUND

Chest computerized tomography (CT) scores are associated with the frequency of future pulmonary exacerbations in people with cystic fibrosis (CF). However, cut-off values to identify children with mild lung disease with different risks for frequent future pulmonary exacerbations have not been identified.

METHODS

Chest CT scans were assessed using the Brody score for participants of the Pulmozyme Early Intervention Trial (PEIT) and Wisconsin Randomized Clinical Trial of CF Newborn Screening (WI RCT). We determined the area under the receiver operating characteristic (ROC) curve for Brody scores and forced expiratory volume in 1 s (FEV₁ ) to compare with the frequency of pulmonary exacerbations up to 10 years later.

RESULTS

There were 60 participants in the PEIT with mean (SD) age 10.6 (1.7) years at the time of the CT and 81 participants in the WI RCT with mean age 11.5 (3.0) years. The Brody score cut-off that best identified children at-risk for ≥0.3 annual pulmonary exacerbations was 3.6 in the PEIT and 2.1 in the WI RCT. There were no statistical differences between ROC curves for the Brody CT score and FEV₁ % predicted in either study (P ≥ 0.4).

CONCLUSIONS

CT score cut-off values that identify children with CF with mild lung disease at different risks for frequent pulmonary exacerbations over an extended follow up period are similar in separate cohorts. Brody scores and FEV₁ % predicted have similar abilities to identify these children, suggesting that FEV₁ % predicted alone may be adequate for predicting future frequency of pulmonary exacerbations.

Predicting disease progression in cystic fibrosis

INTRODUCTION

Progressive lung disease is the major cause of morbidity and mortality in patients with cystic fibrosis (CF). Methods of correctly predicting the future progression of lung disease in patients with CF are essential for directing aggressive treatment to prevent loss of lung function and end stage respiratory failure. Areas covered: This review addresses predictors of respiratory disease progression in patients with CF. We searched Web of Science and Medline, with no restriction on publication date, with the search terms 'cystic fibrosis' and 'disease progression', 'lung function decline', 'prognosis', 'prediction/predictive', 'prediction/prognostic scores', 'risk factors', 'outcome measures/endpoints/disease surrogate', 'longitudinal/long term', 'statistical model', and 'survival'. Expert commentary: Forced expiratory volume in 1 sec (FEV₁) and rate of FEV₁ decline, remain the most significant predictors of mortality in patients with CF while CT scores and airway secretion biomarkers are the main predictors of early CF lung disease. Comprehensive scores incorporating clinical, lung function, imaging and laboratory data will become essential in the future for predicting disease progression and for use in clinical trials. Early interventions may delay the progression of structural lung disease.

Evolution of Antibiotic Resistance in Biofilm and Planktonic Pseudomonas aeruginosa Populations Exposed to Subinhibitory Levels of Ciprofloxacin

The opportunistic Gram-negative pathogen Pseudomonas aeruginosa, known for its intrinsic and acquired antibiotic resistance, has a notorious ability to form biofilms, which often facilitate chronic infections. The evolutionary paths to antibiotic resistance have mainly been investigated in planktonic cultures and are less studied in biofilms. We experimentally evolved P. aeruginosa PAO1 colony biofilms and stationary-phase planktonic cultures for seven passages in the presence of subinhibitory levels (0.1 mg/liter) of ciprofloxacin (CIP) and performed a genotypic (whole-bacterial population sequencing) and phenotypic assessment of the populations. We observed a higher proportion of CIP resistance in the CIP-evolved biofilm populations than in planktonic populations exposed to the same drug concentrations. However, the MICs of ciprofloxacin were lower in CIP-resistant isolates selected from the biofilm population than the MICs of CIP-resistant isolates from the planktonic cultures. We found common evolutionary trajectories between the different lineages, with mutations in known CIP resistance determinants as well as growth condition-dependent adaptations. We observed a general trend toward a reduction in type IV-pilus-dependent motility (twitching) in CIP-evolved populations and a loss of virulence-associated traits in the populations evolved in the absence of antibiotic. In conclusion, our data indicate that biofilms facilitate the development of low-level mutational resistance, probably due to the lower effective drug exposure than in planktonic cultures. These results provide a framework for the selection process of resistant variants and the evolutionary mechanisms involved under the two different growth conditions.

Constrictive Bronchiolitis in Cystic Fibrosis Adolescents with Refractory Pulmonary Decline

RATIONALE

Refractory lung function decline in association with recurrent pulmonary exacerbations is a common, yet poorly explained finding in cystic fibrosis (CF). To investigate the histopathologic mechanisms of pulmonary deterioration during adolescence and early adulthood, we reviewed clinically-indicated lung biopsy specimens obtained during a period of persistent decline.

OBJECTIVES

To determine if peribronchiolar remodeling is prominent in lung biopsy specimens obtained in adolescents with CF refractory to conventional therapy.

METHODS

Six adolescents with CF (mean age, 16.2 y; mean FEV₁, 52% predicted at biopsy) with significant pulmonary deterioration over 12-24 months (mean FEV₁ decline of 14% predicted/year) despite aggressive intervention underwent computed tomography imaging and ultimately lung biopsy to aid clinical management. In addition to routine clinical evaluation, histopathologic investigation included staining for transforming growth factor-β (TGF-β, a genetic modifier of CF lung disease), collagen deposition (a marker of fibrosis), elastin (to evaluate for bronchiectasis), and α-smooth muscle actin (to identify myofibroblasts).

MEASUREMENTS AND MAIN RESULTS

All computed tomography scans demonstrated a mix of bronchiectasis and hyperinflation that was variable across lung regions and within patients. Lung biopsy revealed significant peribronchiolar remodeling, particularly in patients with more advanced disease, with near complete obliteration of the peribronchiolar lumen (constrictive bronchiolitis). Myofibroblast differentiation (a TGF-β-dependent process) was prominent in specimens with significant airway remodeling.

CONCLUSIONS

Constrictive bronchiolitis is widely present in the lung tissue of adolescents with CF with advanced disease and may contribute to impaired lung function that is refractory to conventional therapy (antibiotics, antiinflammatories, and mucolytics). TGF-β-dependent myofibroblast differentiation is prominent in areas of active fibrogenesis and may foster small airway remodeling in CF lung disease.

Congruence Between Pulmonary Function and Computed Tomography Imaging Assessment of Cystic Fibrosis Severity

In cystic fibrosis, pulmonary function tests (PFTs) and computed tomography are used to assess lung function and structure, respectively. Although both techniques of assessment are congruent there are lingering doubts about which PFTs variables show the best congruence with computed tomography scoring. In this study we addressed the issue by reinvestigating the association between PFTs variables and the score of changes seen in computed tomography scans in patients with cystic fibrosis with and without pulmonary exacerbation. This retrospective study comprised 40 patients in whom PFTs and computed tomography were performed no longer than 3 weeks apart. Images (inspiratory: 0.625 mm slice thickness, 0.625 mm interval; expiratory: 1.250 mm slice thickness, 10 mm interval) were evaluated with the Bhalla scoring system. The most frequent structural abnormality found in scans were bronchiectases and peribronchial thickening. The strongest relationship was found between the Bhalla sore and forced expiratory volume in 1 s (FEV1). The Bhalla sore also was related to forced vital capacity (FVC), FEV1/FVC ratio, residual volume (RV), and RV/total lung capacity (TLC) ratio. We conclude that lung structural data obtained from the computed tomography examination are highly congruent to lung function data. Thus, computed tomography imaging may supersede functional assessment in cases of poor compliance with spirometry procedures in the lederly or children. Computed tomography also seems more sensitive than PFTs in the assessment of cystic fibrosis progression. Moreover, in early phases of cystic fibrosis, computed tomography, due to its excellent resolution, may be irreplaceable in monitoring pulmonary damage.

Pulmonary exacerbations and clinical outcomes in a longitudinal cohort of infants and preschool children with cystic fibrosis

Background

Pulmonary exacerbations (PEx) in school aged children and adults with cystic fibrosis (CF) lead to increased morbidity and lung function decline. However, the effect of exacerbations in young children with CF is not fully understood. We sought to characterize the frequency and clinical impact of PEx in a pilot study of infants and pre-school aged children with CF.

Methods

Thirty young children with CF [median (range) 1.5 years (0.2–4.9)] were prospectively followed for 2 years. Exacerbation frequency (hospitalizations and outpatient antibiotic use) was determined. Chest radiographs were performed at enrollment and study completion and assigned a Brasfield score. Lung function at age 7 years was assessed in a subset of children. The association between PEx frequency, chest radiograph score, and lung function was determined using Spearman correlation coefficients and corresponding 95% confidence intervals. Correlations with an absolute magnitude of 0.3 or greater were considered clinically significant.

Results

Over 2 years, participants experienced a median of two PEx (range 0–13). Chest radiograph scores at enrollment and study completion were inversely associated with PEx frequency (R = −0.48 and R = −0.44, respectively). The association between frequency of PEx and lung function [forced expiratory volume in 1 s (FEV₁)] at age 7 years was small (R = 0.20). Higher forced vital capacity (FVC) at 7 years was associated with more frequent PEx during the study (R = 0.44).

Conclusions

Children with worse chest radiograph scores had more frequent PEx over the subsequent 2 years, suggesting a group of patients at higher risk for PEx. Frequent PEx in infants and young children with CF were not associated with lower FEV₁ and FVC at 7 years, although spirometry in this age group may not be a sensitive marker of mild lung disease and disease progression.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0546-8) contains supplementary material, which is available to authorized users.

Capturing complexity in pulmonary system modelling

Respiratory disease is a significant problem worldwide, and it is a problem with increasing prevalence. Pathology in the upper airways and lung is very difficult to diagnose and treat, as response to disease is often heterogeneous across patients. Computational models have long been used to help understand respiratory function, and these models have evolved alongside increases in the resolution of medical imaging and increased capability of functional imaging, advances in biological knowledge, mathematical techniques and computational power. The benefits of increasingly complex and realistic geometric and biophysical models of the respiratory system are that they are able to capture heterogeneity in patient response to disease and predict emergent function across spatial scales from the delicate alveolar structures to the whole organ level. However, with increasing complexity, models become harder to solve and in some cases harder to validate, which can reduce their impact clinically. Here, we review the evolution of complexity in computational models of the respiratory system, including successes in translation of models into the clinical arena. We also highlight major challenges in modelling the respiratory system, while making use of the evolving functional data that are available for model parameterisation and testing.

Fibrosis imaging: Current concepts and future directions

Fibrosis plays an important role in many different pathologies. It results from tissue injury, chronic inflammation, autoimmune reactions and genetic alterations, and it is characterized by the excessive deposition of extracellular matrix components. Biopsies are routinely employed for fibrosis diagnosis, but they suffer from several drawbacks, including their invasive nature, sampling variability and limited spatial information. To overcome these limitations, multiple different imaging tools and technologies have been evaluated over the years, including X-ray imaging, computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT). These modalities can provide anatomical, functional and molecular imaging information which is useful for fibrosis diagnosis and staging, and they may also hold potential for the longitudinal assessment of therapy responses. Here, we summarize the use of non-invasive imaging techniques for monitoring fibrosis in systemic autoimmune diseases, in parenchymal organs (such as liver, kidney, lung and heart), and in desmoplastic cancers. We also discuss how imaging biomarkers can be integrated in (pre-) clinical research to individualize and improve anti-fibrotic therapies.

Quantitative assessment of airway dimensions in young children with cystic fibrosis lung disease using chest computed tomography

OBJECTIVE

To evaluate lung disease progression using airway and artery (AA) dimensions on chest CT over 2-year interval in young CF patients longitudinally and compare to disease controls cross-sectionally.

METHODS

Retrospective analysis of pressure controlled end-inspiratory CTs, 12 routine baseline (CT₁ ) and follow up (CT₂ ) from AREST CF cohort; 12 disease controls with normal CT. All visible AA-pairs were measured perpendicular to the airway axis. Inner and outer airway diameters and wall (outer-inner radius) thickness were divided by adjacent arteries to compute A_in A-, A_out A-, and A_WT A-ratios, respectively. Differences between CF and control data were assessed using mixed effects models predicting AA-ratios per segmental generation (SG). Power calculations were performed with 80% power and ɑ = 0.05.

RESULTS

CF, median age CT₁ 2 years; CT₂ 3.9 years, 5 males. Controls, median age 2.9 years, 10 males. Total of 4798 AA-pairs measured. Cross-sectionally: A_in A-ratio showed no difference between controls and CF CT₁ or CT₂ . A_out A-ratio was significantly higher in CF CT₁ (SG 2-4) and CT₂ (SG 2-5) compared to controls. A_WT A-ratio was increased for CF CT₁ (SG 1-5) and CT₂ (SG 2-6) compared to controls. CF longitudinally: A_in A-ratio was significantly higher at CT₂ compared to CT₁ . Increase in A_out A-ratio at CT₂ compared to CT₁ was visible in SG ≥4. Sample sizes of 21 and 58 would be necessary for 50% and 30% A_out A-ratio reductions, respectively, between CF CT₂ and controls.

CONCLUSION

AA-ratio differences were present in young CF patients relative to disease controls. A_out A-ratio as an objective parameter for bronchiectasis could reduce sample sizes for clinical trials.

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.

In cystic fibrosis, lung clearance index is sensitive to detecting abnormalities appearing at exercise in children with normal spirometry

Symptom-limited incremental cardiopulmonary exercise test was performed in school-age children with clinically stable cystic fibrosis (CF), all with normal spirometry. Physiological parameters were compared between patients with normal lung clearance index (LCI; n=6) and patients with elevated LCI (n=6). Dyspnoea ratings during exercise were similar in both groups. Although no patient had significant dynamic hyperinflation, end-expiratory lung volumes were higher throughout exercise in patients with elevated LCI. In addition, alveolar-arterial oxygen gradient at peak exercise was higher, and SpO₂ was lower in patients with elevated LCI. LCI can thus be regarded as a test performed at rest that predicts some abnormalities appearing at exercise in CF children with normal spirometry.

Bone subtraction radiography in adult patients with cystic fibrosis

Background Bone subtraction radiography allows reading pulmonary changes of chest radiographs more accurately without superimposition of bones. Purpose To evaluate the value of bone subtraction chest radiography using dual energy (DE) bone subtracted lung images compared to conventional radiographs (CR) in adult patients with cystic fibrosis (CF). Material and Methods Forty-nine DE radiographs of 24 patients (16 men) with CF (mean age, 32 years; age range, 18-71 years) were included. Lung function tests were performed within 10 days of the radiographs. Two radiologists evaluated all CR, DE, and CR + DE radiographs using the modified Chrispin-Norman score (CNS) and a five-point score for the confidence. Findings were statistically evaluated by Friedman ANOVA and Wilcoxon matched-pairs test. Results There was significant difference of CNS between CR and DE ( P = 0.044) as well as CR and CR + DE ( P < 0.001). CNS of CR images showed moderate correlation with FEV1% (R = 0.287, P = 0.046) while DE and CR + DE correlated poorly with FEV1% (R = 0.023, P = 0.874 and R = 0.04, P = 0.785). A higher confidence was achieved with bone-subtracted radiographs compared to radiographs alone (median, CR 3.3, DE 3.9, CR + DE 4.1, for both P < 0.001). Conclusion DE radiographs are reliable for the evaluation of adult patients with CF in acute exacerbation. For yearly surveillance, CR and DE radiographs may play a limited role. However, in clinical routine, DE radiographs are useful for adult CF patients and may depict more accurately inflammatory changes than CR.

Comparison of Lung Clearance Index and Magnetic Resonance Imaging for Assessment of Lung Disease in Children with Cystic Fibrosis

RATIONALE

Early onset and progression of lung disease in children with cystic fibrosis (CF) indicates that sensitive noninvasive outcome measures are needed for diagnostic monitoring and early intervention clinical trials. The lung clearance index (LCI) and chest magnetic resonance imaging (MRI) were shown to detect early lung disease in CF; however, the relationship between the two measures remains unknown.

OBJECTIVES

To correlate the LCI with abnormalities detected by MRI and compare the sensitivity of the two techniques to detect responses to therapy for pulmonary exacerbations in children with CF.

METHODS

LCI determined by age-adapted multiple breath washout techniques and MRI studies were performed in 97 clinically stable children with CF across the pediatric age range (0.2-21.1 yr). Furthermore, LCI (n = 26) or MRI (n = 10) were performed at the time of pulmonary exacerbation and after antibiotic therapy. MRI was evaluated using a dedicated morphofunctional score.

MEASUREMENTS AND MAIN RESULTS

The LCI correlated with the global MRI score as well as MRI-defined airway wall abnormalities, mucus plugging, and abnormal lung perfusion in infants and toddlers (P < 0.05 to P < 0.001) and in older children (P < 0.001) with CF. LCI and MRI were sensitive to detect response to antibiotic therapy for pulmonary exacerbations.

CONCLUSIONS

Our results indicate that LCI and MRI may be useful complementary tools for noninvasive monitoring and as quantitative endpoints in early intervention trials in children with CF. In this context, MRI enables detection of disease heterogeneity, including regional mucus plugging associated with abnormal lung perfusion in early CF lung disease. Clinical trial registered with www.clinicaltrials.gov (NCT 02270476).

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.

Microbiology of the Upper and Lower Airways in Pediatric Cystic Fibrosis Patients

Objective To evaluate the microbiology of the upper and lower airways in pediatric cystic fibrosis (CF) patients who underwent sinus surgery. Study Design Retrospective case series with chart review. Setting Tertiary care children's hospital. Subjects and Methods A total of 201 paired sinus and pulmonary cultures from 105 CF patients were identified between 1996 and 2014. Demographics and culture results were analyzed. Results The mean age of patients was 11.2 ± 5.4 years (range, 1-27 years), and approximately one-half were female. Methicillin-sensitive Staphylococcus aureus was the most common pathogen overall. A significantly higher prevalence of Pseudomonas aeruginosa (32% for pulmonary and 37% for sinus cultures) was observed in older patients versus younger patients ( P < .001). There was low to moderate agreement between sinus and pulmonary cultures (Kappa statistic range, 0.03-0.56). The prevalence of methicillin-resistant S aureus (MRSA) increased significantly for lower respiratory tract culture (from 5% to 16%) and sinus culture (from 5% to 27%) between 1996-2004 and 2010-2014 ( P = .016 and P < .001, respectively). The prevalence of positive sinus cultures increased from 40% to 85% between 1996-2004 and 2010-2014 ( P = .018). Patients with pulmonary MRSA were more likely to be coinfected with pulmonary P aeruginosa (risk ratio, 2.4; 95% CI, 1.2-4.8; P = .015) or Aspergillus fumigatus (risk ratio, 2.2; 95% CI, 1.2-4.8; P = .035). Conclusions There is low to moderate correlation between pulmonary and sinus pathogens in CF patients. This is important to consider when treating infections. The prevalence of MRSA in sinus cultures has increased over time and warrants further investigation.

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.

Best practices in the treatment of early cystic fibrosis lung disease

For many years, management of cystic fibrosis (CF) lung disease was focused on symptomatic treatment of chronic lung infection, which is characterized by cough and sputum production, leading to progressive lung damage. With increasing survival and better knowledge of the pathogenesis of CF lung disease, it has become clear that treatment has to start very early because lung damage occurs in young patients, often before obvious symptoms appear. The arrival of new cystic fibrosis transmembrane conductance-regulator (CFTR)-correcting therapies will bring more opportunities to prevent the disease, apart from only treating chronic lung infection. In this review, a summary of the current knowledge of early CF lung disease is provided, based on animal model studies, as well as on data obtained from well structured follow-up programs after newborn screening (NBS). The most important clinical guidelines for treating young CF patients are also summarized.

Quantitative computed tomography analysis of the airways in patients with cystic fibrosis using automated software: correlation with spirometry in the evaluation of severity

Objective

To perform a quantitative analysis of the airways using automated software, in computed tomography images of patients with cystic fibrosis, correlating the results with spirometric findings.

Materials and Methods

Thirty-four patients with cystic fibrosis were studied-20 males and 14 females; mean age 18 ± 9 years-divided into two groups according to the spirometry findings: group I (n = 21), without severe airflow obstruction (forced expiratory volume in first second [FEV1] > 50% predicted), and group II (n = 13), with severe obstruction (FEV1 ≤ 50% predicted). The following tracheobronchial tree parameters were obtained automatically: bronchial diameter, area, thickness, and wall attenuation.

Results

On average, 52 bronchi per patient were studied. The number of bronchi analyzed was higher in group II. The correlation with spirometry findings, especially between the relative wall thickness of third to eighth bronchial generation and predicted FEV1, was better in group I.

Conclusion

Quantitative analysis of the airways by computed tomography can be useful for assessing disease severity in cystic fibrosis patients. In patients with severe airflow obstruction, the number of bronchi studied by the method is higher, indicating more bronchiectasis. In patients without severe obstruction, the relative bronchial wall thickness showed a good correlation with the predicted FEV1.

Hyperpolarized 129Xe for investigation of mild cystic fibrosis lung disease in pediatric patients

BACKGROUND

Cystic fibrosis (CF) is a genetic disease which carries high morbidity and mortality from lung-function decline. Monitoring disease progression and treatment response in young patients is desirable, but serial imaging via CT is often considered prohibitive, and detailed functional information cannot be obtained using conventional imaging techniques. Hyperpolarized ¹²⁹Xe magnetic resonance imaging (MRI) can depict and quantify regional ventilation, but has not been investigated in pediatrics. We hypothesized that ¹²⁹Xe MRI is feasible and would demonstrate ventilation defects in mild CF lung disease with greater sensitivity than FEV₁.

METHODS

11 healthy controls (age 6-16years) and 11 patients with mild CF (age 8-16years, Forced Expiratory Volume (FEV₁) percent predicted >70%) were recruited for this study. Nine CF patients had an FEV₁>85%. Each subject was imaged via hyperpolarized ¹²⁹Xe MRI, and the ventilation defect percentage (VDP) was measured. FEV₁ and VDP were compared between the groups.

RESULTS

FEV₁ for controls was 100.3%±8.5% (mean±sd) and for CF patients was 97.9%±16.0% (p=0.67). VDP was 6.4%±2.8% for controls and 18.3%±8.6% for CF (p<0.001). When considering the 9 CF patients with normal FEV₁ (>85%), the mean FEV₁ was 103.1%±12.3% (p=0.57 compared to controls) and VDP was 15.4%±6.3% (p=0.002).

CONCLUSIONS

Hyperpolarized ¹²⁹Xe MRI demonstrated ventilation defects in CF patients with normal FEV₁ and more effectively discriminated CF from controls than FEV₁. Thus ¹²⁹Xe may be a useful outcome measure to detect mild CF lung disease, to investigate regional lung function in pediatric lung diseases, and to follow disease progression.

A longitudinal study characterising a large adult primary ciliary dyskinesia population

Primary ciliary dyskinesia (PCD) in adults has not been well described. In this retrospective observational study we aimed to characterise a large adult population and identify features associated with disease progression.

We retrospectively analysed 151 adult patients at a single tertiary centre at baseline and longitudinally for a median of 7 years.

We found significant variation in age at diagnosis (median 23.5 years; range <1–72 years). Older age at diagnosis was associated with impaired baseline forced expiratory volume in 1 s (FEV1) (r= −0.30, p=0.01) and increased Pseudomonas aeruginosa colonisation (difference in medians 17 years (95% CI 4.5–20 years); p=0.002). Lung function decline was estimated at FEV1 decline of 0.49% predicted per year. Lung function decline was associated with ciliary ultrastructure, with microtubular defect patients having the greatest decline (p=0.04). High-resolution computed tomography (HRCT) scores of severity of bronchial wall dilatation (p<0.001) and extent of bronchiectasis (p=0.03) additionally showed evidence of modifying FEV1 decline with age.

Our study reveals that a large proportion of adult PCD patients are diagnosed late, with impaired FEV1 and increased P. aeruginosa colonisation. Increased disease burden on HRCT and ciliary ultrastructure may predict progressive lung function decline. This study characterises a large adult PCD population, identifies features associated with disease progression and highlights the need for prospective trials to determine whether early diagnosis of high-risk subgroups alongside optimal management can modify disease progression.

VISIBILITY OF STRUCTURES OF RELEVANCE FOR PATIENTS WITH CYSTIC FIBROSIS IN CHEST TOMOSYNTHESIS: INFLUENCE OF ANATOMICAL LOCATION AND OBSERVER EXPERIENCE

The aims of this study were to assess the visibility of pulmonary structures in patients with cystic fibrosis (CF) in digital tomosynthesis (DTS) using computed tomography (CT) as reference and to investigate the dependency on anatomical location and observer experience. Anatomical structures in predefined regions of CT images from 21 patients were identified. Three observers with different levels of experience rated the visibility of the structures in DTS by performing a head-to-head comparison with visibility in CT. Visibility of the structures in DTS was reported as equal to CT in 34 %, inferior in 52 % and superior in 14 % of the ratings. Central and peripheral lateral structures received higher visibility ratings compared with peripheral structures anteriorly, posteriorly and surrounding the diaphragm (p ≤ 0.001). Reported visibility was significantly higher for the most experienced observer (p ≤ 0.01). The results indicate that minor pathology can be difficult to visualise with DTS depending on location and observer experience. Central and peripheral lateral structures are generally well depicted.

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.

Chest CT abnormalities and quality of life: relationship in adult cystic fibrosis

BACKGROUND

To evaluate the relationship between lung parenchymal abnormalities on chest CT and health-related quality of life in adult cystic fibrosis (CF).

METHODS

The chest CT scans of 101 consecutive CF adults (mean age 27.8±7.9, 64 males) were prospectively scored by two blinded radiologists in consensus using a modified Bhalla score. Health-related quality of life was assessed using the revised Quittner Cystic Fibrosis Questionnaire (CFQ-R). Multiple regressions were performed with each of the CFQ-R domains and all clinical and imaging findings to assess independent correlations.

RESULTS

There were 18 inpatients and 83 outpatients. For the cohort of inpatients, CT abnormalities were significantly (P<0.005 for all) associated with Respiratory Symptoms (Air Trapping), and also with Social Functioning (Consolidation) and Role Functioning (Consolidation). For outpatients, CT abnormalities were significantly (P<0.005 for all) associated with Respiratory Symptoms (Consolidation) and also with Physical Functioning (Consolidation), Vitality (Consolidation, Severity of Bronchiectasis), Eating Problems (airway wall thickening), Treatment Burden (Total CT Score), Body Image (Severity of Bronchiectasis) and Role Functioning (Tree-in-bud nodules). Consolidation was the commonest independent CT predictor for both inpatients (predictor for 2 domains) and outpatients (predictor in 3 domains). Several chest CT abnormalities excluded traditional measures such as FEV1 and BMI from the majority of CFQ-R domains.

CONCLUSIONS

Chest CT abnormalities are significantly associated with quality of life measures in adult CF, independent of clinical or spirometric measurements.

The Role of Computed Tomography in Monitoring Patients with Cystic Fibrosis

Cystic fibrosis is the most common lethal autosomal recessive disorder in the Caucasian population. Although the survival rate in patients constantly improves, lung damage is still the major cause of morbidity and mortality in patients with cystic fibrosis. In clinical practice, evaluation of patients' pulmonary state is made by combination of monitoring of lung function and more directly by assessing the lung structure in imaging studies. Studies showed that computed tomography findings are more sensitive as compared to the pulmonary function tests. Computed tomography can identify a wide range of morphological abnormalities in patients with cystic fibrosis, such as bronchiectasis (which is progressive, irreversible and probably the most relevant structural change in cystic fibrosis) peribronchial thickening, mucous plugging and many other disorders that occur in the course of the disease. Computed tomography has a crucial role in the assessment of pulmonary damage over time, detecting complications and monitoring treatment effects in patients with cystic fibrosis.

Clinical Practice Guidelines From the Cystic Fibrosis Foundation for Preschoolers With Cystic Fibrosis

Cystic fibrosis (CF) clinical care guidelines exist for the care of infants up to age 2 years and for individuals ≥6 years of age. An important gap exists for preschool children between the ages of 2 and 5 years. This period marks a time of growth and development that is critical to achieve optimal nutritional status and maintain lung health. Given that disease often progresses in a clinically silent manner, objective and sensitive tools that detect and track early disease are important in this age group. Several challenges exist that may impede the delivery of care for these children, including adherence to therapies. A multidisciplinary committee was convened by the CF Foundation to develop comprehensive evidence-based and consensus recommendations for the care of preschool children, ages 2 to 5 years, with CF. This document includes recommendations in the following areas: routine surveillance for pulmonary disease, therapeutics, and nutritional and gastrointestinal care.

Factors associated with radiologic progression of non-cystic fibrosis bronchiectasis during long-term follow-up

BACKGROUND AND OBJECTIVE

Non-cystic fibrosis (CF) bronchiectasis is a chronic airway inflammatory disease, exhibiting a diverse array of clinical courses. The purpose of this study was to determine the factors that predict radiologic progression of non-CF bronchiectasis during a long-term follow-up.

METHODS

We reviewed the electronic medical records that included pulmonary function test data from non-CF bronchiectasis patients, who were older than 18 years of age with a follow-up of computerized tomography for more than 5 years. The original Bhalla score was used to determine the radiologic severity of non-CF bronchiectasis.

RESULTS

A total of 155 patients (mean age, 59.6 years; male, 45.2%) were included for the final analysis. The mean follow up time was 7.11 ± 1.42 (5-10) years. The baseline Bhalla score was 9.52 ± 3.14 (4-19), and the change of Bhalla score was 0.55 ± 1.14 (-2 to 5). The Bhalla score was increased in 56 patients (36.1%) but not in 99 patients (63.9%). The Bhalla score change was significantly associated with the age at diagnosis (p = 0.037), body mass index (BMI, p = 0.012), chronic infection of Pseudomonas aeruginosa (p = 0.005) or isolation of nontuberculous mycobacterium (p = 0.042) in respiratory specimens. In a multivariate analysis, BMI and isolation of P. aeruginosa were significantly related with the Bhalla score change.

CONCLUSION

The radiologic progression of non-CF bronchiectasis was associated with lower BMI and isolation of P. aeruginosa in respiratory specimens.

Chest computed tomography predicts the frequency of pulmonary exacerbations in children with cystic fibrosis

RATIONALE

Abnormalities on chest computed tomography (CT) in children with cystic fibrosis (CF) have been shown to correlate with short-term measures of lung disease. Chest CT scores offer promise as a potential surrogate end point in CF; however, there is limited information available on the ability of chest CT scores to predict future morbidity.

OBJECTIVES

Determine whether chest CT scores are associated with the rate of pulmonary exacerbations over the next 10 years.

METHODS

Ten years of follow-up data were obtained from the CF Foundation Patient Registry for 60 children enrolled in the Pulmozyme Early Intervention Trial and who had chest CT scans at baseline.

MEASUREMENTS AND MAIN RESULTS

Multivariable Poisson regression was used to compare Brody CT scores and the number of pulmonary exacerbations in the following 10 years. At the time of the chest CT, the mean (SD) age was 10.6 (1.7) years. A 1-point increase in the Brody CT score was associated with an increase in the mean (95% confidence interval) rate of pulmonary exacerbations of 1.39 (1.15, 1.67) (P < 0.001). Brody CT scores were more strongly associated with the number of pulmonary exacerbations than FEV1 % predicted at the time of the chest CT (P = 0.037 by chi-square test).

CONCLUSIONS

There is a significant association between Brody CT scores and the rate of pulmonary exacerbations up to 10 years later. This association is stronger than for FEV1 obtained at the time of the CT, suggesting that chest CT scores offer improved ability to predict future outcomes.

Effect of enterovirus D68 on Lung Clearance Index in patients with cystic fibrosis: A case report

Cystic fibrosis (CF) causes airways obstruction and a decline in percent predicted forced expiratory volume in 1 s (FEV₁%). FEV₁% is an objective measure of a pulmonary exacerbation of CF; improvement in FEV₁% is the endpoint used often to determine success of treatment of these acute declines in pulmonary health. Lung Clearance Index (LCI), derived from multiple breath inert gas washout (MBW) test, measures ventilation inhomogeneity and small airways dysfunction. In the United States in 2014–2015, enterovirus D68 (EV-D68), a novel virus, led to hospitalizations in children because of respiratory distress. This report describes 2 patients with CF admitted for pulmonary exacerbations who were enrolled in an inpatient study to assess patient satisfaction and utility of MBW to measure LCI. Diagnostic testing indicated that these patients were infected with EV-D68. Although their FEV₁% improved to their previous baseline following treatment for pulmonary exacerbation, it was discordant with LCI. We discuss LCI as a novel measure of pulmonary function and hypothesize that, based on these cases, it may be a more sensitive indicator of ongoing post-viral airways dysfunction as compared to FEV₁%.

Antimicrobial resistance, respiratory tract infections and role of biofilms in lung infections in cystic fibrosis patients

Lung infection is the main cause of morbidity and mortality in patients with cystic fibrosis and is mainly dominated by Pseudomonas aeruginosa. The biofilm mode of growth makes eradication of the infection impossible, and it causes a chronic inflammation in the airways. The general mechanisms of biofilm formation and antimicrobial tolerance and resistance are reviewed. Potential anti-biofilm therapeutic targets such as weakening of biofilms by quorum-sensing inhibitors or antibiotic killing guided by pharmacokinetics and pharmacodynamics of antibiotics are presented. The vicious circle of adaptive evolution of the persisting bacteria imposes important therapeutic challenges and requires development of new drug delivery systems able to reach the different niches occupied by the bacteria in the lung of cystic fibrosis patients.

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.

HRCT in cystic fibrosis in patients with CFTR I1234V mutation: Assessment of scoring systems with low dose technique using multidetector system and correlation with pulmonary function tests

Background and Aims:

Pulmonary changes in patients with cystic fibrosis (CF) with CFTR I1234V mutation have not been extensively documented. Impact of geographic influence on phenotypical expression is largely unknown. This descriptive clinical study presents the high-resolution computed tomography (HRCT) pulmonary findings and computed tomography (CT) scoring with respect to pulmonary function tests (PFT) in a small subset of CF group.

Materials and Methods:

We examined 29 patients between 2 and 31 years of age with CFTR I1234V mutation. HRCT and PFT were performed within 2 weeks of each other. Imaging abnormalities on HRCT were documented and analyzed by utilizing the scoring system described by Bhalla et al., Brody et al., Helbich et al.,and Santamaria et al. Efficacy of the scoring system with respect to PFT was compared.

Statistical Analysis:

Inter-observer reliability of the scoring systems was tested using intraclass correlation (ICC) between the two observers. Spearman correlation coefficients were calculated between the scoring systems and between the scoring systems and PFT results.

Results:

In our study, right upper and middle lobes were the most frequently involved sites of involvement. Bronchiectasis and peribronchial thickening were the most frequent imaging findings. Scores with all four scoring systems were reproducible, with good ICC coefficient of 0.69. There was good agreement between senior radiologists in all scoring systems.

Conclusion:

We noted pulmonary imaging abnormalities in a large majority (96%) of our CF patients. There was no significant difference in the CT scores observed from various systems. The CT evaluation system by Broody is detailed and time consuming, and is ideal for research and academic setup. On the other hand, the systems by Bhalla and Santamaria are easy to use, quick, and equally informative. We found the scoring system by Santamaria preferable over that of Bhalla by virtue of additional points of evaluation and ease of use, and therefore better suited for busy clinical practice.

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.