Chest computed tomography scans should be considered as a routine investigation in cystic fibrosis

Point of care lung ultrasound in preschool children with cystic fibrosis: a case-controlled, prospective, pilot study

AIMS

Respiratory complications in Cystic Fibrosis (CF) are still the leading cause of death nowadays in these patients. High-Resolution Computed Tomography is the gold standard method for staging lung disease in CF. In this study we assessed lung ultrasound findings in asymptomatic preschool patients affected by CF.

METHODS

This is a case-control study with a total of 70 enrolled patients (20 patients affected by CF, 50 healthy controls) aged from 31 to 6 years. All included patients were without intercurrent lung problems and without antibiotic therapy in the last 30 days. For each patient a lung Point of Care Ultrasound (POCUS) of lung was performed.

RESULTS

B lines < 3 and sub-pleural consolidations < 1 cm were statistically more frequent in CF patients, both in terms of number of affected patients (p 0.02 and p 0.0001 respectively) and frequency (p 0.0181 and p 0.0001 respectively); the prevalence of B lines < 3 in control group was high (47.73%) however the prevalence of sub-pleural consolidations was very low (2.27%). In both groups coalescent B lines affected a greater number of infants and were in higher number of findings than patients aged between 2 and 6 years.

CONCLUSIONS

The presence of multiple subpleural pulmonary consolidations < 1 cm in asymptomatic preschool children could be a ultrasound markers of subclinical pulmonary disease such as CF. POCUS of lung is confirmed as a useful tool for the clinician as confirmation of a clinical suspicion, help reduce the use of ionizing radiation.

Paediatric Thoracic Imaging in Cystic Fibrosis in the Era of Cystic Fibrosis Transmembrane Conductance Regulator Modulation

Cystic fibrosis (CF) is one of the most common progressive life-shortening genetic conditions worldwide. Ground-breaking translational research has generated therapies that target the primary cystic fibrosis transmembrane conductance regulator (CFTR) defect, known as CFTR modulators. A crucial aspect of paediatric CF disease is the development and progression of irreversible respiratory disease in the absence of clinical symptoms. Accurate thoracic diagnostics have an important role to play in this regard. Chest radiographs are non-specific and insensitive in the context of subtle changes in early CF disease, with computed tomography (CT) providing increased sensitivity. Recent advancements in imaging hardware and software have allowed thoracic CTs to be acquired in paediatric patients at radiation doses approaching that of a chest radiograph. CFTR modulators slow the progression of CF, reduce the frequency of exacerbations and extend life expectancy. In conjunction with advances in CT imaging techniques, low-dose thorax CT will establish a central position in the routine care of children with CF. International guidelines regarding the choice of modality and timing of thoracic imaging in children with CF are lagging behind these rapid technological advances. The continued progress of personalised medicine in the form of CFTR modulators will promote the emergence of personalised radiological diagnostics.

Chest magnetic resonance imaging in cystic fibrosis: technique and clinical benefits

Cystic fibrosis (CF) is one of the most common inherited and life-shortening pulmonary diseases in the Caucasian population. With the widespread introduction of newborn screening and the development of modulator therapy, tremendous advances have been made in recent years both in diagnosis and therapy. Since paediatric CF patients tend to be younger and have lower morbidity, the type of imaging modality that should be used to monitor the disease is often debated. Computed tomography (CT) is sensitive to many pulmonary pathologies, but radiation exposure limits its use, especially in children and adolescents. Conventional pulmonary magnetic resonance imaging (MRI) is a valid alternative to CT and, in most cases, provides sufficient information to guide treatment. Given the expected widespread availability of sequences with ultra-short echo times, there will be even fewer reasons to perform CT for follow-up of patients with CF. This review aims to provide an overview of the process and results of monitoring CF with MRI, particularly for centres not specialising in the disease.

Going the Extra Mile: Why Clinical Research in Cystic Fibrosis Must Include Children

This is an exciting time for research and novel drug development in cystic fibrosis. However, rarely has the adage, “Children are not just little adults” been more relevant. This article is divided into two main sections. In the first, we explore why it is important to involve children in research. We discuss the potential benefits of understanding a disease and its treatment in children, and we highlight that children have the same legal and ethical right to evidence-based therapy as adults. Additionally, we discuss why extrapolation from adults may be inappropriate, for example, medication pharmacokinetics may be different in children, and there may be unpredictable adverse effects. In the second part, we discuss how to involve children and their families in research. We outline the importance and the complexities of selecting appropriate outcome measures, and we discuss the role co-design may have in improving the involvement of children. We highlight the importance of appropriate staffing and resourcing, and we outline some of the common challenges and possible solutions, including practical tips on obtaining consent/assent in children and adolescents. We conclude that it is unethical to simply rely on extrapolation from adult studies because research in young children is challenging and that research should be seen as a normal part of the paediatric therapeutic journey.

Lung Ultrasound in Children with Cystic Fibrosis in Comparison with Chest Computed Tomography: A Feasibility Study

Background: Cystic fibrosis (CF) lung disease determines the outcome of this condition. For lung evaluation processes, computed tomography (CT) is the gold standard, but also causes irradiation. Lately, lung ultrasound (LUS) has proven to be reliable for the diagnosis of consolidations, atelectasis, and/or bronchiectasis. The aim of our study was to evaluate the value of a newly conceived LUS score by comparing it to the modified Bhalla CT score. A further aim was to evaluate the correlation between the score and the lung clearance index (LCI). Methods: Patients with CF were screened by LUS, followed by a CT scan. Spearman’s test was used for correlations. Results: A total of 98 patients with CF were screened, and 57 were included in the study; their mean age was 11.8 ± 5.5 (mean ± SD) years. The mean LUS score was 5.88 ± 5.4 SD. The LUS CF score had a very strong correlation with the CT score of rs = 0.87 (p = 0.000). LUS showed a good sensibility for detecting atelectasis (Se = 83.7%) and consolidations (Se = 94.4%). A lower Se (77.7%) and Sp (9%) were found for cylindrical bronchiectasis. Conclusion: Our study shows that LUS and the lung CF score are parameters that can be used with a complementary role in the diagnosis and monitoring of CF lung disease in children.

Artificial intelligence in CT for quantifying lung changes in the era of CFTR modulators

RATIONALE

Chest computed tomography (CT) remains the imaging standard for demonstrating cystic fibrosis airway structural disease in vivo. However, visual scorings as an outcome measure are time-consuming, require training, and lack high reproducibility.

OBJECTIVE

To validate a fully automated artificial intelligence-driven scoring of cystic fibrosis lung disease severity.

METHODS

Data were retrospectively collected in three cystic fibrosis reference centers, between 2008 and 2020, in 184 patients 4 to 54-years-old. An algorithm using three two-dimensional convolutional neural networks was trained with 78 patients' CTs (23 530 CT slices) for the semantic labeling of bronchiectasis, peribronchial thickening, bronchial mucus, bronchiolar mucus, and collapse/consolidation. 36 patients' CTs (11 435 CT slices) were used for testing versus ground-truth labels. The method's clinical validity was assessed in an independent group of 70 patients with or without lumacaftor/ivacaftor treatment (n=10 and 60, respectively) with repeat examinations. Similarity and reproducibility were assessed using Dice coefficient, correlations using Spearman test, and paired comparisons using Wilcoxon rank test.

MEASUREMENT AND MAIN RESULTS

The overall pixelwise similarity of artificial intelligence-driven versus ground-truth labels was good (Dice coefficient=0.71). All artificial intelligence-driven volumetric quantifications had moderate to very good correlations to a visual imaging scoring (p<0.001) and fair to good correlations to FEV1% at pulmonary function test (p<0.001). Significant decreases in peribronchial thickening (p=0.005), bronchial mucus (p=0.005), bronchiolar mucus (p=0.007) volumes were measured in patients with lumacaftor/ivacaftor. Conversely, bronchiectasis (p=0.002) and peribronchial thickening (p=0.008) volumes increased in patients without lumacaftor/ivacaftor. The reproducibility was almost perfect (Dice>0.99).

CONCLUSION

Artificial intelligence allows a fully automated volumetric quantification of cystic fibrosis-related modifications over an entire lung. The novel scoring system could provide a robust disease outcome in the era of effective CFTR modulator therapy.

The Clinical Use of Lung MRI in Cystic Fibrosis: What, Now, How?

To assess airway and lung parenchymal damage noninvasively in cystic fibrosis (CF), chest MRI has been historically out of the scope of routine clinical imaging because of technical difficulties such as low proton density and respiratory and cardiac motion. However, technological breakthroughs have emerged that dramatically improve lung MRI quality (including signal-to-noise ratio, resolution, speed, and contrast). At the same time, novel treatments have changed the landscape of CF clinical care. In this contemporary context, there is now consensus that lung MRI can be used clinically to assess CF in a radiation-free manner and to enable quantification of lung disease severity. MRI can now achieve three-dimensional, high-resolution morphologic imaging, and beyond this morphologic information, MRI may offer the ability to sensitively differentiate active inflammation vs scarring tissue. MRI could also characterize various forms of inflammation for early guidance of treatment. Moreover, functional information from MRI can be used to assess regional, small-airway disease with sensitivity to detect small changes even in patients with mild CF. Finally, automated quantification methods have emerged to support conventional visual analyses for more objective and reproducible assessment of disease severity. This article aims to review the most recent developments of lung MRI, with a focus on practical application and clinical value in CF, and the perspectives on how these modern techniques may converge and impact patient care soon.

Cystic Fibrosis Mortality in Childhood. Data from European Cystic Fibrosis Society Patient Registry

Data collected in the European Cystic Fibrosis Society Patient Registry (ECFSPR) database were used to investigate whether risk factors for death in childhood and adolescents CF patients have different impact in countries of different income. In this way, it is possible to recognize where interventions could improve the quality of care and survival in these patients. We matched deceased and alive patients by age, country, year of follow-up. Multivariable logistic models were developed. In the years of this study, the ECFSPR collected information on 24,416 patients younger than 18 years: 7830 patients were from countries with low/middle income and 16,586 from countries with high income; among these the dead are 102 and 107 (p < 0.001), respectively. The use of oxygen, forced expiratory volume in one second (FEV₁) below 40% and BMI standard deviation score (SDS) below −2 represent risk factors for death. However, some patients from countries with high income remain alive even if their values of FEV₁% and BMI-SDS were low, and some deceased patients from countries with high income had high values of FEV₁% (>60%). Evaluation of mortality in pediatric age may reflect the availability of resources for CF diagnosis and treatment in some countries.

Methicillin-resistant Staphylococcus aureus in cystic fibrosis patients: do we need to care? A cohort study

CONTEXT AND OBJECTIVE

The prevalence of a variety of potentially pathogenic microorganisms in cystic fibrosis patients, such as methicillin-resistant Staphylococcus aureus (MRSA), has increased over the past decade. Given the increasing prevalence of MRSA and the few data available in the literature, better understanding of the clinical repercussions of colonization by this bacterium in cystic fibrosis patients becomes essential. This study aimed to evaluate the repercussions of chronic colonization by MRSA in cystic fibrosis patients.

DESIGN AND SETTING

Retrospective cohort study from January 2004 to December 2013 in a cystic fibrosis reference center.

METHODS

Each patient with cystic fibrosis was evaluated for nutritional status (body mass index, BMI, and BMI percentile), pulmonary function and tomographic abnormalities (modified Bhalla scores) at the time of chronic colonization by MRSA or methicillin-susceptible Staphylococcus aureus (MSSA) and throughout the study period.

RESULTS

Twenty pairs of patients were included. There were no significant differences between the groups regarding nutritional characteristics. Spirometric data showed a trend towards greater obstruction of the airways in patients with MRSA. Patients with MRSA presented greater structural damage to their lungs, demonstrated not only by the total Bhalla score but also by its parameters individually.

CONCLUSIONS

Patients colonized by MRSA presented greater functional and structural respiratory impairment at the time of chronic colonization. Disease progression was also faster in patients chronically colonized by MRSA than in those with MSSA. This was shown through comparisons that avoided possible confounding variables.

Technological advances shed light on left ventricular cardiac disturbances in cystic fibrosis

Cystic fibrosis (CF), the most common autosomal recessive lethal disease in Caucasians, causes chronic pulmonary disease and can lead to cor pulmonale with right ventricular dysfunction. The presence of the cystic fibrosis transmembrane conductance regulator (CFTR) in cardiac myocardia has prompted debate regarding possible defective ion channel-induced cardiomyopathy. Clinical heart disease in CF is considered rare and is restricted to case reports. It has been unclear if this is due to the lack of physiological importance of CFTR in the heart, the relatively short lifespan of those with CF, or a technical inability to detect subclinical disease. Extensive echocardiographic investigations have yielded contradictory results, leading to the dogma that left ventricular defects in CF occur secondary to lung disease. In this review, we consider why studies examining heart function in CF have not provided clarity on this topic. We then focus on data from new echocardiographic and magnetic resonance imaging technology, which are providing greater insight into cardiac function in CF and demonstrating that, in addition to secondary effects from pulmonary disease, there may be an intrinsic primary defect in the CF heart. With advancing lifespans and activity levels, understanding the risk of cardiac disease is vital to minimizing morbidity in adults with CF.

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.

Computed tomography dose optimisation in cystic fibrosis: A review

Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population worldwide, with respiratory disease remaining the most relevant source of morbidity and mortality. Computed tomography (CT) is frequently used for monitoring disease complications and progression. Over the last fifteen years there has been a six-fold increase in the use of CT, which has lead to a growing concern in relation to cumulative radiation exposure. The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality, but fulfil the requirements of a diagnostic quality CT. Dose-optimisation, particularly in CT, is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 mSv, a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation. This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

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.

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.

Comparison of Image Quality and Radiation Dose between High-Pitch Mode and Low-Pitch Mode Spiral Chest CT in Small Uncooperative Children: The Effect of Respiratory Rate

OBJECTIVES

To compare image quality and radiation dose between high-pitch mode (HPM) and low-pitch mode (LPM) CT in young children.

MATERIALS AND METHODS

Forty-seven children (mean age 35.6 months; range, 0-126 months) underwent 49 CT examinations in HPM or LPM and were divided into high or low respiratory rate (RR) groups. A qualitative image quality was compared between the two modes. The volume CT dose index (CTDIvol) and dose-length product (DLP) were evaluated from the dose reports, and effective doses were assessed using a paediatric phantom.

RESULTS

Image quality was generally better for HPM than LPM (diagnostic acceptance score, 4.00 vs. 3.46, P = 0.004); the difference was more prominent in the high RR group (4.00 vs. 3.22, P = 0.001). However, there was no significant difference in the low RR group. The mean DLP value was higher in HPM than LPM (29.48 mGy · cm vs. 23.46 mGy · cm, P = 0.022), while CTDIvol was not significantly different. The total effective radiation dose was 26 % higher in HPM than LPM (1.82 mSv vs. 1.44 mSv).

CONCLUSIONS

LPM can be considered for paediatric lung evaluation in young children with low RRs to reduce radiation dose while maintaining favourable image quality.

KEY POINTS

• Radiation exposure is higher on high-pitch "Flash spiral mode" than on low-pitch "X-CARE mode". • "Flash spiral mode" generally showed better image quality than "X-CARE mode". • Difference in image quality was more prominent in the high RR group. • There was no difference in image quality in the low RR group. • "X-CARE mode" should be considered in a limited population with low RRs.

CT density distribution analysis in patients with cystic fibrosis: correlation with pulmonary function and radiologic scores

RATIONALE AND OBJECTIVES

The progressive changes in lung morphology observed in cystic fibrosis (CF) can potentially affect the statistical distribution of computed tomography (CT) density values. This study aimed to characterize the lung CT density distributions by quantifying indices of the kurtosis and skewness of the lung density distribution and to compare these indices to radiologic scores and lung function parameters in children and young adults with CF.

MATERIALS AND METHODS

CT scans and lung function of 26 patients with CF were retrospectively examined. The Bhalla radiologic scoring was performed separately, in random order, by two expert radiologists, blinded to the patient's identity, age, clinical status, results of lung function tests, and the other paired observer's score.

RESULTS

Positive relations were evidenced between the log indices of lung density distribution kurtosis (iKurtosis) and the overall radiologic scores (RS) of both observers (R = 0.58; P < .001 vs RS1 and R = 0.71; P < .001 vs RS2). A similar relationship was evidenced with the log index of the degree of distribution asymmetry (iSkewness; R = 0.62; P < .001 vs RS1 and R = 0.62; P < .001 vs RS2). Log-iKurtosis and log-iSkewness were related to FEV1 (R = -0.56; P < 10(-5) and R = -0.55; P < 10(-5)) and to residual volume (R = 0.40; P < .001 and R = 0.45; P < .001, respectively). Both radiologic scores showed significant relation with lung function. The correlation between RS1 and RS2 was excellent (R = 0.93), with a Cohen weighted kappa of 0.43.

CONCLUSIONS

Characteristic indices of lung CT density distribution are correlated to lung function and radiologic scores in patients with CF and merit further evaluation as part of more comprehensive automated methods for quantifying CF lung CT data.

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.

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.

Evaluation of the impact of organ-specific dose reduction on image quality in pediatric chest computed tomography

BACKGROUND

Organ-specific dose reduction significantly reduces the radiation exposure of radiosensitive organs.

OBJECTIVE

The purpose of this study was to assess the impact of a novel organ-specific dose reduction algorithm on image quality of pediatric chest CT.

MATERIALS AND METHODS

We included 28 children (mean age 10.9 ± 4.8 years, range 3-18 years) who had contrast-enhanced chest CT on a 128-row scanner. CT was performed at 100 kV using automated tube current modulation and a novel organ-specific dose-reduction algorithm (XCare™; Siemens, Forchheim, Germany). Seven children had a previous chest CT performed on a 64-row scanner at 100 kV without organ-specific dose reduction. Subjective image quality was assessed using a five-point scale (1-not diagnostic; 5-excellent). Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were assessed in the descending aorta.

RESULTS

Overall mean subjective image quality was 4.1 ± 0.6. In the subgroup of the seven children examined both with and without organ-specific dose reduction, subjective image quality was comparable (score 4.4 ± 0.5 with organ-specific dose reduction vs. 4.4 ± 0.7 without it; P > 0.05). There was no significant difference in mean signal-to-noise ratio and contrast-to-noise ratio with organ-specific dose reduction (38.3 ± 10.1 and 28.5 ± 8.7, respectively) and without the reduction (35.5 ± 8.5 and 26.5 ± 7.8, respectively) (P > 0.05). Volume computed tomography dose index (CTDIvol) and size-specific dose estimates did not differ significantly between acquisitions with the organ-specific dose reduction (1.7 ± 0.8 mGy) and without the reduction (1.7 ± 0.8 mGy) (P > 0.05).

CONCLUSION

Organ-specific dose reduction does not have an impact on image quality of pediatric chest CT and can therefore be used in clinical practice to reduce radiation dose of radiosensitive organs such as breast and thyroid gland.

Cystic and cavitary lung lesions in children: radiologic findings with pathologic correlation

A number of diseases produce focal or multiple thin-walled or thick-walled air- or fluid-containing cysts or cavitary lung lesions in both infants and children. In infants and children, there is a spectrum of focal or multifocal cystic and cavitary lung lesions including congenital lobar emphysema, congenital cystic adenomatoid malformation, pleuropulmonary blastoma, bronchogenic cyst, pulmonary sequestration, Langerhans cell histiocytosis, airway diseases, infectious diseases (bacterial infection, fungal infection, etc.), hydatid cysts, destroid lung, and traumatic pseudocyst. For the evaluation of cystic or cavitary lung lesion in infants and children, imaging plays an important role in accurate early diagnosis and optimal patient management. Therefore, a practical imaging approach based on the most sensitive and least invasive imaging modality in an efficient and cost-effective manner is paramount. We reviewed the conventional radiographs and computed tomography findings of the most common cystic and cavitary lung lesions in infants and children.

Radiography, tomosynthesis, CT and MRI in the evaluation of pulmonary cystic fibrosis: an untangling review of the multitude of scoring systems

Objective

The first radiographic scoring system for pulmonary cystic fibrosis was presented in 1958. Since then a multitude of scoring systems for radiography and computed tomography (CT) have been presented, recently also for tomosynthesis and magnetic resonance imaging (MRI). The aim of the current review was to analyse and compare the plethora of scoring systems for cystic fibrosis, especially regarding which scoring components are considered most important.

Methods

Four scoring systems for chest radiography, one for tomosynthesis, eight for CT and one for MRI were compared regarding components evaluated and their terminology; the areas scored; scoring levels; the weighting of each component in percentage of the total score; and the calculations for the final score.

Results

In most radiological scoring systems the lungs are evaluated for increased volume, bronchial wall thickening, bronchiectasis, mucus plugging, atelectasis and consolidation. In addition, for instance abscesses, bullae, septal thickening, mosaic perfusion, ground glass opacities and air trapping are evaluated in some CT scoring systems. Pleural affection and perfusion defects are scored on MRI.

Conclusions

Bronchiectasis alone, or in combination with mucus plugging, is given the highest weighting in most scoring systems and is thus commonly considered to be the most significant finding when evaluating cystic fibrosis lung disease.

Teaching points

Scoring of examinations is used for comparison of outcome in studies.

Scoring of examinations can also be used for monitoring disease progression.

Cystic fibrosis can be scored on radiography, tomosynthesis, CT or MRI.

The typical imaging findings of cystic fibrosis depend on the imaging modality used.

Bronchiectasis is commonly considered the most significant finding when scoring cystic fibrosis.

Cystic fibrosis: detecting changes in airway inflammation with FDG PET/CT

PURPOSE

To determine if fluorine 18 fluorodeoxyglucose (FDG) positron emission tomographic (PET)/computed tomographic (CT) imaging can depict a treatment effect from intravenous antibiotics for pulmonary exacerbation in cystic fibrosis (CF).

MATERIALS AND METHODS

The study was approved by the institutional review board of the Hospital for Sick Children and by Health Canada. Consent was obtained from all subjects. Patients with CF who were between 6 and 18 years of age and were admitted for a pulmonary exacerbation were eligible for the study. FDG PET/CT examinations (with low-dose CT) were performed on days 1 and 14 of admission (±72 hours). PET activity was quantified by using standardized uptake values (SUVs) through assessment of background activity (mean SUV [SUV(mean)]) and superimposed focal uptake (maximum SUV [SUV(max)]) for each lung zone. CT studies were scored by using the CF-CT model. SUVs from pre- and posttherapy studies were compared by using paired t tests. Unpaired t tests were used to compare data in patients with CF and data in 10 control subjects.

RESULTS

Twenty patients with CF were enrolled. Antibiotic therapy resulted in a significant decrease in SUV(max) (mean difference, 2.3 ± 2.1 [standard deviation], P < .0001). Pretherapy SUV(max) and SUV(mean) and posttherapy SUV(max) were significantly different from those in control subjects. The change in SUV(max) and percentage predicted forced expiratory volume in 1 second was negatively correlated. (R = -0.72, P = .004). Overall CF-CT scores significantly correlated with SUV(max) (R = 0.40, P = .01).

CONCLUSION

FDG PET/CT is a useful tool for detecting inflammatory changes resulting from treatment for pulmonary exacerbations in pediatric patients with CF. Inflammatory changes detected by using FDG PET/CT correlated with lung function, sputum neutrophil counts, and CF-CT scores. Analyzing focal lung inflammation (with SUV(max)) may be a feasible way to measure airway inflammation in patients with CF.

Description and validation of a scoring system for tomosynthesis in pulmonary cystic fibrosis

OBJECTIVES

To design and validate a scoring system for tomosynthesis (digital tomography) in pulmonary cystic fibrosis.

METHODS

A scoring system dedicated to tomosynthesis in pulmonary cystic fibrosis was designed. Three radiologists independently scored 88 pairs of radiographs and tomosynthesis examinations of the chest in 60 patients with cystic fibrosis and 7 oncology patients. Radiographs were scored according to the Brasfield scoring system and tomosynthesis examinations were scored using the new scoring system.

RESULTS

Observer agreements for the tomosynthesis score were almost perfect for the total score with square-weighted kappa >0.90, and generally substantial to almost perfect for subscores. Correlation between the tomosynthesis score and the Brasfield score was good for the three observers (Kendall's rank correlation tau 0.68, 0.77 and 0.78). Tomosynthesis was generally scored higher as a percentage of the maximum score. Observer agreements for the total score for Brasfield score were almost perfect (square-weighted kappa 0.80, 0.81 and 0.85).

CONCLUSIONS

The tomosynthesis scoring system seems robust and correlates well with the Brasfield score. Compared with radiography, tomosynthesis is more sensitive to cystic fibrosis changes, especially bronchiectasis and mucus plugging, and the new tomosynthesis scoring system offers the possibility of more detailed and accurate scoring of disease severity.

KEY POINTS

Tomosynthesis is more sensitive than conventional radiography for pulmonary cystic fibrosis changes. The radiation dose from chest tomosynthesis is low compared with computed tomography. Tomosynthesis may become useful in the regular follow-up of patients with cystic fibrosis.

The sensitivity of lung disease surrogates in detecting chest CT abnormalities in children with cystic fibrosis

RATIONALE

Chest CT scans detect structural abnormalities in children with cystic fibrosis (CF), even when pulmonary function tests (PFTs) are normal. The use of chest CT is limited in clinical practice, because of concerns over expense, increased resource utilization, and radiation exposure. Quantitative chest radiography scores are useful in detecting mild lung disease, but whether they are sensitive to the presence of CT scan abnormalities has not been evaluated.

OBJECTIVE

To determine in a cross-sectional study if quantitative chest radiography is a more sensitive marker of chest CT abnormalities than other lung disease surrogates.

METHODS

Brody chest CT scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. We determined the sensitivity for Wisconsin (WCXR) and Brasfield (BCXR) chest radiography scores, PFTs, positive cultures for P. aeruginosa (PA), and parental report of symptoms to detect a Brody score worse than the median score for study participants.

MEASUREMENTS AND MAIN RESULTS

The mean FEV(1) for the study population was 91% predicted. Abnormal WCXR and BCXR scores had the highest sensitivity to detect a chest CT score worse than the median; abnormal PFTs, parental report of symptoms, and the presence of PA had much lower sensitivity (P < 0.001).

CONCLUSIONS

In this cross sectional study, quantitative chest radiography has excellent sensitivity to detect an abnormal chest CT and may have a role in monitoring lung disease progression in children with CF.

Pulmonary magnetic resonance imaging for airway diseases

Pulmonary magnetic resonance (MR) imaging has been put forward as a new research and diagnostic tool mainly to overcome the limitations of computed tomography and nuclear medicine studies. However, pulmonary MR imaging has been difficult to use because of inherently low proton density, a multitude of air-tissue interfaces, which create significant magnetic field distortions and are commonly referred to as susceptibility artifacts; diminishing signal in the lung; and respiratory and/or cardiac motion artifacts. To overcome these drawbacks of pulmonary MR imaging, technical advances made during the last decade in sequencing, scanner and coil, adaptation of parallel imaging techniques, and utilization of contrast media have been reported as being useful for functional and morphologic assessment of various pulmonary diseases including airway diseases. This review article covers (1) pulmonary MR techniques for morphologic and functional assessment of airway diseases, and (2) pulmonary MR imaging for cystic fibrosis, asthma, and chronic obstructive pulmonary disease. Pulmonary MR imaging provides not only morphology-related but also pulmonary function-related information. It has the potential to replace nuclear medicine studies for the identification of regional pulmonary function and may perform a complementary role in airway disease assessment instead of nuclear medicine study. We believe that the findings of further basic studies as well as clinical applications of this new technique will validate the real significance of pulmonary MR imaging for the future of airway disease assessment and its usefulness for diagnostic radiology and pulmonary medicine.

Lung clearance index: clinical and research applications in children

Multiple breath washout (MBW) has been demonstrated to be sensitive for assessing ventilation inhomogeneity (VI). VI is supposed to reflect changes in peripheral airways which are not apparent using spirometry. The lung clearance index (LCI) is the most robust parameter to quantify VI, and is largely independent of age; therefore, it potentially qualifies as a surrogate outcome parameter for clinical and research purposes, particularly during childhood. This review summarizes the current evidence regarding the clinical value of measuring LCI in children. Feasibility, reproducibility and diagnostic accuracy have been demonstrated; available data confirm that LCI is superior to spirometry in detecting small air way disease. However, there is little information regarding the value in the individual patient, and sparse longitudinal data looking at its prognostic value. Currently, only in patients with Cystic Fibrosis, it appears likely that knowledge of LCI will be useful for routine clinical management.

Air trapping on chest CT is associated with worse ventilation distribution in infants with cystic fibrosis diagnosed following newborn screening

BACKGROUND

In school-aged children with cystic fibrosis (CF) structural lung damage assessed using chest CT is associated with abnormal ventilation distribution. The primary objective of this analysis was to determine the relationships between ventilation distribution outcomes and the presence and extent of structural damage as assessed by chest CT in infants and young children with CF.

METHODS

Data of infants and young children with CF diagnosed following newborn screening consecutively reviewed between August 2005 and December 2009 were analysed. Ventilation distribution (lung clearance index and the first and second moment ratios [LCI, M(1)/M(0) and M(2)/M(0), respectively]), chest CT and airway pathology from bronchoalveolar lavage were determined at diagnosis and then annually. The chest CT scans were evaluated for the presence or absence of bronchiectasis and air trapping.

RESULTS

Matched lung function, chest CT and pathology outcomes were available in 49 infants (31 male) with bronchiectasis and air trapping present in 13 (27%) and 24 (49%) infants, respectively. The presence of bronchiectasis or air trapping was associated with increased M(2)/M(0) but not LCI or M(1)/M(0). There was a weak, but statistically significant association between the extent of air trapping and all ventilation distribution outcomes.

CONCLUSION

These findings suggest that in early CF lung disease there are weak associations between ventilation distribution and lung damage from chest CT. These finding are in contrast to those reported in older children. These findings suggest that assessments of LCI could not be used to replace a chest CT scan for the assessment of structural lung disease in the first two years of life. Further research in which both MBW and chest CT outcomes are obtained is required to assess the role of ventilation distribution in tracking the progression of lung damage in infants with CF.

Computed tomography and magnetic resonance imaging in cystic fibrosis lung disease

Computed tomography (CT) is the current "gold standard" for assessment of lung morphology and is so far the most reliable imaging modality for monitoring cystic fibrosis (CF) lung disease. CT has a much higher radiation exposure than chest x-ray. The cumulative radiation dose for life-long repeated CT scans has limited its use for CF patients as their life expectancy increases. Clearly, no dose would be preferable over low dose when the same or more relevant information can be obtained. Magnetic resonance imaging (MRI) is comparable to CT with regard to the detection of most morphological changes in the CF lung. It is thought to be less sensitive to detect small airway disease. At the same time, MRI is superior to CT when it comes to the assessment of functional changes such as altered pulmonary perfusion. The recommendation is to further reduce radiation dose related to the use of CT and to use MRI in the follow-up of morphological changes where possible.

Development of low-dose protocols for thin-section CT assessment of cystic fibrosis in pediatric patients

PURPOSE

To develop low-dose thin-section computed tomographic (CT) protocols for assessment of cystic fibrosis (CF) in pediatric patients and determine the clinical usefulness thereof compared with chest radiography.

MATERIALS AND METHODS

After institutional review board approval and informed consent from patients or guardians were obtained, 14 patients with CF and 11 patients without CF (16 male, nine female; mean age, 12.6 years ± 5.4 [standard deviation]; range, 3.5-25 years) who underwent imaging for clinical reasons underwent low-dose thin-section CT. Sections 1 mm thick (protocol A) were used in 10 patients, and sections 0.5 mm thick (protocol B) were used in 15 patients at six levels at 120 kVp and 30-50 mA. Image quality and diagnostic acceptability were scored qualitatively and quantitatively by two radiologists who also quantified disease severity at thin-section CT and chest radiography. Effective doses were calculated by using a CT dosimetry calculator.

RESULTS

Low-dose thin-section CT was performed with mean effective doses of 0.19 mSv ± 0.03 for protocol A and 0.14 mSv ± 0.04 for protocol B (P < .005). Diagnostic acceptability and depiction of bronchovascular structures at lung window settings were graded as almost excellent for both protocols, but protocol B was inferior to protocol A for mediastinal assessment (P < .02). Patients with CF had moderate lung disease with a mean Bhalla score of 9.2 ± 5.3 (range, 0-19), compared with that of patients without CF (1.1 ± 1.4; P < .001). There was excellent correlation between thin-section CT and chest radiography (r = 0.88-0.92; P < .001).

CONCLUSION

Low-dose thin-section CT can be performed at lower effective doses than can standard CT, approaching those of chest radiography. Low-dose thin-section CT could be appropriate for evaluating bronchiectasis in pediatric patients, yielding appropriate information about lung parenchyma and bronchovascular structures.

The use of high resolution computerized tomography (HRCT) of the chest in evaluating the effect of tobramycin solution for inhalation in cystic fibrosis lung disease

OBJECTIVES

To compare the usefulness of HRCT of the chest versus spirometric measures (PFTs) in evaluating the effect of tobramycin solution for inhalation (TSI) in cystic fibrosis (CF).

METHODS

Thirty-two CF patients with mostly mild lung disease age > or = 6 years, were enrolled in a double-blind, placebo-controlled pilot study. Patients were chronically colonized with Pseudomonas aeruginosa for at least 6 months prior to and at enrollment. If patients were on TSI, they were taken off for at least 3 months prior to enrollment. Duration was 6 months; 31 subjects completed the study. HRCT and PFTs were evaluated at baseline, after 28 days of treatment and at the end of the study. Study medication was administered as 5 ml nebulized treatment twice a day for 28 days followed by 28 days off (one cycle). Study consisted of three cycles. Two radiologists scored all films using a validated system. A total HRCT score consists of the sum of subscores: linear opacities, hyperinflation, nodular opacities, peribronchial thickening, mucous plugging, and bronchiectasis; each subscore could range from 0 to 80, with potential total scores varying from 0 to 480. The percent of the maximum possible HRCT score was then calculated and used for all comparisons.

RESULTS

Using two tailed paired t-test, the percent maximum HRCT score decreased by 1.4 +/- 2.6% (mean +/- SD) (P = 0.049) and 0.3 +/- 2.8% (P = 0.63) for the TSI group and decreased by 0.1 +/- 1.5% (P = 0.74) and increased by 0.6 +/- 1.8% (P = 0.23) for the placebo group between visits 1 and 2, and visits 1 and 3, respectively. The data were then analyzed using a mixed model utilizing changes in scores over the durations of the study for each group. The change of HRCT score for the TSI group was -0.24/day (P = 0.02) and -0.03/day (P = 0.22), and for the control group the change was -0.01 (P = 0.93) and 0.02 (P = 0.29) between visits 1 and 2, and visits 1 and 3 respectively. FEF(25-75)% and FEV(1)% changes were not statistically significant using both analyses.

CONCLUSION

HRCT seems to be more sensitive in detecting treatment effect than PFT in CF patients with mild lung disease, especially following the first treatment period (visit 2). Total HRCT score showed some improvement at the end of the study, though not statistically significant. This is probably due to obtaining the HRCT an average of 30 days after completion of the TSI treatment, and selection of study population with mostly mild lung disease. This could indicate that the most significant improvement in the total HRCT score in this patient population occurs after the first treatment period with TSI.

The future in paediatric respirology

The authors were given the charge of providing a vision of the future in paediatric respirology. Themes selected for being ripe for this visionary analysis include bronchopulmonary dysplasia (BPD), asthma, cystic fibrosis (CF), lung infections, obstructive sleep disordered breathing (OSDB) and pulmonary diagnostics and monitoring. A profound reduction or elimination of BPD is seen. Given the strong genetic component of this disease, genetic biomarkers will likely be identified that will permit much earlier recognition of BPD susceptibility and potentially the ability to modify disease course by altering gene expression. The ultimate prevention of BPD will be to prevent prematurity, but recognition of both the genetic basis of BPD and the inflammatory background should lead to improved prevention and therapy. A clear understanding and definition of asthma phenotypes will lead to more specific and targeted therapy, earlier detection and prevention, better monitoring of severity and adherence to therapy, lower mortality and decreased inappropriate diagnosis of asthma. The greatest opportunities in asthma care will likely come through tools to improve adherence to effective therapy. Also, areas are identified where better therapies are needed such as in patients with severe mucus hypersecretion (secretory hyperresponsiveness) especially in those with life-threatening asthma. The future of CF is easier to foresee with early successes seen in clinical trials. After the expected ability to correct the CF transmembrane regulator, care will need to change and additional research will be needed. Additionally, the face of CF is changing with more adults than children presently having the disease. This will necessitate changes to our approach to treating this disease in a fortunately aging population. If we are going to affect the worldwide lung health of children, we will need to address respiratory infections particularly pneumonia, tuberculosis and HIV-associated infections. Preventive, diagnostic and treatment strategies will shape the future face of these problems. The availability of inexpensive, readily available, and rapid molecular techniques to identify true infection (including HIV and tuberculosis) may permit earlier use of effective therapy while preventing the inappropriate use of antibiotics for common viral diseases. Sleep medicine will continue to be an important aspect of paediatric pulmonology. The evaluation of OSDB cannot rely on full-night attended polysomnography due to limited access. Identifying reliable markers of end organ dysfunction in children with OSDB may permit more rapid identification of patients in need of intervention like CPAP and assisted breathing. In addition, management options, as an alternative to adenotonsilectomy, are listed with a call for further research. Pulmonary diagnostics and monitoring will see the development and refinement of tools like the lung clearance index and the analysis of exhaled gases, volatiles and dissolved biomarkers of inflammation as techniques that might help clinicians identify both the initiation of inflammation while it is more amenable to therapy, and to identify more readily the early changes associated with chronic lung diseases in children. The authors hope that these visionary articles will generate comments, arguments, inspiration, and perhaps even motivate funding agencies.

Cystic fibrosis: are volumetric ultra-low-dose expiratory CT scans sufficient for monitoring related lung disease?

PURPOSE

To assess whether chest computed tomography (CT) scores from ultra-low-dose end-expiratory scans alone could suffice for assessment of all cystic fibrosis (CF)-related structural lung abnormalities.

MATERIALS AND METHODS

In this institutional review board-approved study, 20 patients with CF aged 6-20 years (eight males, 12 females) underwent low-dose end-inspiratory CT and ultra-low-dose end-expiratory CT. Informed consent was obtained. Scans were randomized and scored by using the Brody-II CT scoring system to assess bronchiectasis, airway wall thickening, mucus plugging, and opacities. Scoring was performed by two observers who were blinded to patient identity and clinical information. Mean scores were used for all analyses. Statistical analysis included assessment of intra- and interobserver variability, calculation of intraclass correlation coefficients (ICCs), and Bland-Altman plots.

RESULTS

Median age was 12.6 years (range, 6.3-20.3 years), median forced expiratory volume in 1 second was 100% (range, 46%-127%) of the predicted value, and median forced vital capacity was 99% (range, 61%-123%) of the predicted value. Very good agreement was observed between end-inspiratory and end-expiratory CT scores for Brody-II total score (ICC = 0.96), bronchiectasis (ICC = 0.98), airway wall thickening (ICC = 0.94), mucus plugging (ICC = 0.96), and opacities (ICC = 0.90). Intra- and interobserver agreement were good to very good (ICC range, 0.70-0.98). Bland-Altman plots showed that differences in scores were independent of score magnitude.

CONCLUSION

In this pilot study, CT scores from end-expiratory and end-inspiratory CT match closely, suggesting that ultra-low-dose end-expiratory CT alone may be sufficient for monitoring CF-related lung disease. This would help reduce radiation dose for a single investigation by up to 75%.

Lung morphology assessment using MRI: a robust ultra-short TR/TE 2D steady state free precession sequence used in cystic fibrosis patients

To evaluate feasibility and diagnostic quality of ultra-short TR/TE two-dimensional (2D) steady state free precession (SSFP) MRI for cystic fibrosis (CF) patients. We performed lung MRI at 1.5 Tesla in 20 CF-patients (6-17 years, 12 males). Axial, coronal, and sagittal sections were acquired in inspiration and expiration with maximum breath-hold time 10 s. MR and CT images were scored using a modified Brody scoring system to assess bronchiectasis, mucous plugging, atelectasis/consolidations, and air trapping. All images were scored by two experienced observers. A complete MR investigation took maximally 15 min. Maximal breath-holds were only 10 s and well tolerated. MRI identified major bronchiectasis, mucous plugging and atelectasis. End-expiratory scans showed patches of parenchyma with reduced signal intensity that may corresponded to areas of trapped air on expiratory CT scans. This MRI protocol based on ultra-short TR/TE 2D SSFP is quick and well tolerated and provides highly relevant imaging features as seen on CT in CF patients. Most importantly, the SNR of the expiratory scans enables to visualize air trapping. The preliminary results of this study suggest MRI as a noteworthy additional imaging tool for routine monitoring of CF patients.

A new scoring system in Cystic Fibrosis: statistical tools for database analysis - a preliminary report

Background

Cystic fibrosis is the most common fatal genetic disorder in the Caucasian population. Scoring systems for assessment of Cystic fibrosis disease severity have been used for almost 50 years, without being adapted to the milder phenotype of the disease in the 21^st century. The aim of this current project is to develop a new scoring system using a database and employing various statistical tools. This study protocol reports the development of the statistical tools in order to create such a scoring system.

Methods

The evaluation is based on the Cystic Fibrosis database from the cohort at the Royal Children's Hospital in Melbourne. Initially, unsupervised clustering of the all data records was performed using a range of clustering algorithms. In particular incremental clustering algorithms were used. The clusters obtained were characterised using rules from decision trees and the results examined by clinicians. In order to obtain a clearer definition of classes expert opinion of each individual's clinical severity was sought. After data preparation including expert-opinion of an individual's clinical severity on a 3 point-scale (mild, moderate and severe disease), two multivariate techniques were used throughout the analysis to establish a method that would have a better success in feature selection and model derivation: 'Canonical Analysis of Principal Coordinates' and 'Linear Discriminant Analysis'. A 3-step procedure was performed with (1) selection of features, (2) extracting 5 severity classes out of a 3 severity class as defined per expert-opinion and (3) establishment of calibration datasets.

Results

(1) Feature selection: CAP has a more effective "modelling" focus than DA.

(2) Extraction of 5 severity classes: after variables were identified as important in discriminating contiguous CF severity groups on the 3-point scale as mild/moderate and moderate/severe, Discriminant Function (DF) was used to determine the new groups mild, intermediate moderate, moderate, intermediate severe and severe disease. (3) Generated confusion tables showed a misclassification rate of 19.1% for males and 16.5% for females, with a majority of misallocations into adjacent severity classes particularly for males.

Conclusion

Our preliminary data show that using CAP for detection of selection features and Linear DA to derive the actual model in a CF database might be helpful in developing a scoring system. However, there are several limitations, particularly more data entry points are needed to finalize a score and the statistical tools have further to be refined and validated, with re-running the statistical methods in the larger dataset.

A novel sidestream ultrasonic flow sensor for multiple breath washout in children

OBJECTIVE

Inert gas multiple breath washout (MBW) for measuring Lung Clearance Index using mass spectrometry and 4% sulfur hexafluoride (SF(6)) as the tracer gas has been shown to be sensitive for detecting early Cystic Fibrosis (CF) lung disease. However, mass spectrometry requires bulky equipment and is expensive to buy and maintain. A novel sidestream ultrasonic device may overcome this problem. The aims of this study were to assess the feasibility and clinical validity of measuring lung volume (functional residual capacity, FRC) and the LCI using the sidestream ultrasonic flow sensor in children and adolescents with CF in relation to spirometry and plain chest radiographs.

PATIENTS AND METHODS

MBW using the sidestream ultrasonic device and conventional spirometry were performed in 26 patients with CF and 22 healthy controls.

RESULTS

In the controls (4.7-17.7 years) LCI was similar to that reported using mass spectrometry (mean (SD) 6.7 (0.5)). LCI was elevated in 77% of the CF children (6.8-18.9 years), whereas spirometry was abnormal in only 38.5%, 61.5%, and 26.9% for FEV(1), MEF(25), and FEV(1)/FVC, respectively. This was more marked in children <10 years. LCI correlated with the Crispin-Norman score, whereas FEV(1) did not.

CONCLUSIONS

Sidestream ultrasonic MBW is a valid and simple alternative to mass spectrometry for assessing ventilation homogeneity in children.

Pathogenesis of Bronchiectasis

Cystic fibrosis (CF) typically follows a more severe clinical course than non-CF bronchiectasis. Despite this recognized difference, the underpinnings of respiratory biology support a common pathogeneses of the anatomic deformations of bronchiectasis. This article reviews the observed manifestations among the related diseases of bronchiectasis and CF and discusses some of their similarities and differences. As more details of the mechanisms of bronchiectasis are unveiled, more parallels among the seemingly disparate causes of CF and non-CF bronchiectasis are recognized. With these insights, more opportunities to halt the vicious circle have become apparent.