Computed tomography correlates with pulmonary exacerbations in children with cystic fibrosis

Exacerbations in cystic fibrosis. 1: Epidemiology and pathogenesis

With the improving survival of patients with cystic fibrosis (CF), the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is an acute pulmonary exacerbation. Clinical and microbial epidemiology studies of CF pulmonary exacerbations continue to provide important insight into the course, prognosis and complications of the disease. This review provides a summary of the pathophysiology, clinical epidemiology and microbial epidemiology of a CF pulmonary exacerbation.

The opportunities and challenges of developing imaging biomarkers to study lung function and disease

Recent advances in imaging offer exciting opportunities to develop and validate lung-specific biomarkers as valuable adjuncts to diagnosis, tests of treatment efficacy, and/or treatment monitoring. State-of-the-art structural, functional, and molecular imaging methods allow the lungs to be visualized noninvasively in vivo at submillimeter and subsecond spatial and temporal scales. However, the development and validation of imaging biomarkers present some special challenges, including the following: equipment evaluation, procedure standardization, data regarding reproducibility and replication, interrater variability, the production and measurement of reference standards, sensitivity to interventions or disease progression, intersubject variance, choice of image reconstruction and segmentation algorithms, automated versus observer-dependent image analysis, data acquisition during conditions of standardized lung volume, whether a reliable association can be demonstrated between the imaging biomarker and a clinical endpoint, and whether its use will have a favorable cost-effective impact on drug development or disease management. Establishing such performance characteristics, especially for single investigators at single institutions, can be daunting if not impossible for costly biomarkers such as imaging. Therefore, to take full advantage of the opportunities presented by state-of-the-art imaging methods, new approaches to analytic and clinical validation must be developed in collaboration with industry, foundation, and federal funding agencies.

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

RATIONALE

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

OBJECTIVES

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

METHODS

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

MEASUREMENTS AND MAIN RESULTS

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

CONCLUSIONS

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

High-Resolution CT of Patients with Primary Ciliary Dyskinesia

OBJECTIVE

High-resolution CT is an important tool in the detection and management of bronchiectasis, but there is little information about high-resolution CT findings in primary ciliary dyskinesia (PCD). We analyzed all high-resolution CT studies of the chest available for a cohort of PCD patients to identify an associated pattern of high-resolution CT changes.

MATERIALS AND METHODS

High-resolution CT studies were available for 45 PCD patients from 42 families with ranges of age and disease severity. The images were assessed for severity and distribution of bronchiectasis, peribronchial thickening, mucous plugging, and other findings. A bronchiectasis severity score was calculated. CT findings were correlated with phenotypic findings, including situs type, ciliary ultrastructural defect, nasal level of nitric oxide, forced expiratory volume in 1 second, and microbiologic findings in the airways.

RESULTS

Twenty-nine adults (mean age, 42 +/- 15 years; age range, 21-73 years) and 16 children (mean age, 8 +/- 4 years; age range, 1-14 years) were included; 26 (58%) of the patients were women or girls. Situs inversus totalis (38%) or heterotaxy (18%) was identified in 56% of the patients. A high (9%) prevalence of pectus excavatum was identified. High-resolution CT of all of the adult and 56% of the pediatric patients showed bronchiectasis in a predominantly middle and lower lobe distribution. The right middle lobe was most commonly involved. Bronchiectasis severity score correlated with older age and worse pulmonary function.

CONCLUSION

High-resolution CT shows that pulmonary disease related to PCD predominantly involves the middle and lower lobes of the lungs. In adults, high-resolution CT findings negative for bronchiectasis may have a role in excluding the diagnosis of PCD. Correlation of severity of disease on high-resolution CT with patient phenotype gives further insight into the diversity and natural history of PCD.

Making airway clearance successful

Airway clearance therapy (ACT) requires a substantial time, effort and resource commitment on the part of families and patients with cystic fibrosis (CF). Lack of compliance with caregiver recommendations and adherence to a proposed therapeutic plan occurs more than 50% of the time with ACT and is particularly common in adolescents. There is a large menu of ACT devices and techniques from which to choose. Increasing adherence and compliance requires an effort on the part of the CF team, including regular visits to the CF center, matching the patient to the device or technique based on lifestyle and disease severity, selecting appropriate outcome measures and monitoring adherence and compliance. Successful ACT also requires the CF team to understand individual patient situations, individualize ACT programs and accept a realistic level of patient participation.

Computed tomography and cystic fibrosis: promises and problems

Computed tomography (CT) has two potential roles in the evaluation of patients with cystic fibrosis (CF) lung disease: as a diagnostic test primarily for the detection of supervening complications and as a monitoring tool in clinical research. Interest in the latter role has gained momentum in the last 5 years because of two factors: (1) therapeutic options for CF lung disease are developing rapidly, hence the need for an outcome measure that can be applied in clinical intervention trials; and (2) it has become clear that traditional outcome measures such as pulmonary function tests are relatively insensitive to the early structural damage that occurs in CF. Several recent studies have shown that CT can be used as a potential surrogate outcome measure, although its suitability for this specific role is controversial and still under investigation. This review summarises current concepts relating to the research applications of CT in CF, with particular emphasis on the evidence supporting the use of CT as a surrogate outcome measure in clinical trials.

Pulmonary abnormalities on high-resolution CT demonstrate more rapid decline than FEV1 in adults with cystic fibrosis

BACKGROUND

FEV1 may remain stable while high-resolution CT (HRCT) appearances deteriorate in children with cystic fibrosis (CF). However, spirometry results commonly decline in older age groups.

OBJECTIVES

To compare the rate of decline in HRCT abnormalities and spirometry results over time in an adult cohort with CF.

METHODS

The HRCT scans of 39 consecutive patients (19 males and 20 females; mean age, 22 years; range, 16 to 48 years) with two HRCT scans > 18 months apart were randomly and blindly scored using a modified Bhalla scoring system by two independent chest radiologists. Age, body mass index, spirometry, and sputum cultures were recorded at the time of both HRCTs. Rates of change in clinical parameters and HRCT abnormalities were calculated and compared using repeated-measures analysis of variance.

RESULTS

Mean FEV1 declined at a rate of - 2.3% per year, while mean HRCT total score declined at a rate of -2.7% per year. Several individual HRCT abnormalities as well as HRCT total scores declined significantly faster than FEV1 (p < 0.001). Six patients showed stable spirometry results but worsening HRCT scores. Mucus plugging and extent of bronchiectasis deteriorated at a more rapid rate in the group with mildly impaired lung function. Air trapping, collapse/consolidation, peribronchial thickening, severity of bronchiectasis, and generations of bronchial divisions involved deteriorated at a more rapid rate in the group with moderate-to-severely impaired lung function.

CONCLUSIONS

Adult CF patients have more rapid rates of decline in HRCT abnormalities than in spirometry results. Individual HRCT abnormalities decline at different rates depending on the degree of lung function impairment.

Update on the application of chest computed tomography scanning to cystic fibrosis

PURPOSE OF REVIEW

To summarize the role of chest computed tomography as a tool to evaluate cystic fibrosis lung disease, and to describe what abnormalities can be detected using computed tomography and how computed tomography can be used in clinical practice.

RECENT FINDINGS

Pulmonary function tests are only an indirect measure of lung structure, and are insensitive to localized and early structural abnormalities. Computed tomography is able to detect small areas with localized severe damage. The differentiation between normal and abnormal on computed tomography is relatively easy. In half of cystic fibrosis patients, the information obtained from pulmonary function tests is discordant with the information obtained from computed tomography.

SUMMARY

Cystic fibrosis patients show lung inflammation and infection starting early in life. This leads to irreversible structural lung damage such as bronchiectasis and air trapping. Cystic fibrosis lung disease varies widely between patients. The primary aim of therapy is to prevent structural damage and to conserve lung function. Adequate monitoring of cystic fibrosis lung disease is paramount to tailor treatment to a patient's need. Computed tomography is currently the best tool to monitor lung structure, and pulmonary function tests are the best to monitor lung function.

Lung structure abnormalities, but normal lung function in pediatric bronchiectasis

BACKGROUND

Bronchiectasis is not considered to be uncommon in children anymore. The relationship between pulmonary function and severity of bronchiectasis is still controversial.

STUDY OBJECTIVES

To assess the extent and severity of bronchiectasis through high-resolution CT (HRCT) scan score, and to correlate it with clinical, microbiological, and functional data.

PATIENTS AND METHODS

Forty-three white children with HRCT-diagnosed bronchiectasis were studied. Bronchiectasis extent, bronchial wall thickening severity, and bronchial wall dilatation severity were evaluated using the Reiff score. Clinical, microbiological, and spirometry results were related to total HRCT scan score and to subscores as well.

RESULTS

The percentages of affected lobes were as follows: right lower lobe, 65%; middle lobe, 56%; left lower lobe, 51%; right upper lobe, 37%; lingula, 30%; and left upper lobe, 30% (chi(2) = 18.4; p = 0.002). The mean (+/- SEM) HRCT score was 20 +/- 2.6. Total score or subscores of bronchiectasis extent, bronchial wall thickening severity, and bronchial wall dilatation severity were not significantly related to FEV(1) and FVC. Seventy-four percent of patients had asthma. The age at the onset of cough correlated with age at the time of the HRCT scan (p = 0.004) and with the presence of asthma (p = 0.01). Positive findings of deep throat or sputum cultures were found more frequently in atopic patients (p = 0.02) and asthmatic (p < 0.01) patients, and in children who were < 2 years of age at the onset of cough (p < 0.01).

CONCLUSIONS

Normal lung function may coexist with HRCT scan abnormalities and does not exclude damage to the bronchial structure. Pulmonary function is not an accurate method for assessing the severity of lung disease in children with bronchiectasis.