Automated computer-based CT stratification as a predictor of outcome in hypersensitivity pneumonitis.

BACKGROUND: Hypersensitivity pneumonitis (HP) has a variable clinical course. Modelling of quantitative CALIPER-derived CT data can identify distinct disease phenotypes. Mortality prediction using CALIPER analysis was compared to the interstitial lung disease gender, age, physiology (ILD-GAP) outcome model. METHODS: CALIPER CT analysis of parenchymal patterns in 98 consecutive HP patients was compared to visual CT scoring by two radiologists. Functional indices including forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLco) in univariate and multivariate Cox mortality models. Automated stratification of CALIPER scores was evaluated against outcome models. RESULTS: Univariate predictors of mortality included visual and CALIPER CT fibrotic patterns, and all functional indices. Multivariate analyses identified only two independent predictors of mortality: CALIPER reticular pattern (p = 0.001) and DLco (p < 0.0001). Automated stratification distinguished three distinct HP groups (log-rank test p < 0.0001). Substitution of automated stratified groups for FVC and DLco in the ILD-GAP model demonstrated no loss of model strength (C-Index = 0.73 for both models). Model strength improved when automated stratified groups were combined with the ILD-GAP model (C-Index = 0.77). CONCLUSIONS: CALIPER-derived variables are the strongest CT predictors of mortality in HP. Automated CT stratification is equivalent to functional indices in the ILD-GAP model for predicting outcome in HP. KEY POINTS: • Computer CT analysis better predicts mortality than visual CT analysis in HP. • Quantitative CT analysis is equivalent to functional indices for prognostication in HP. • Prognostication using the ILD-GAP model improves when combined with quantitative CT analysis.

UK Lung Cancer RCT Pilot Screening Trial: baseline findings from the screening arm provide evidence for the potential implementation of lung cancer screening.

BACKGROUND: Lung cancer screening using low-dose CT (LDCT) was shown to reduce lung cancer mortality by 20% in the National Lung Screening Trial. METHODS: The pilot UK Lung Cancer Screening (UKLS) is a randomised controlled trial of LDCT screening for lung cancer versus usual care. A population-based questionnaire was used to identify high-risk individuals. CT screen-detected nodules were managed by a pre-specified protocol. Cost effectiveness was modelled with reference to the National Lung Cancer Screening Trial mortality reduction. RESULTS: 247 354 individuals aged 50-75 years were approached; 30.7% expressed an interest, 8729 (11.5%) were eligible and 4055 were randomised, 2028 into the CT arm (1994 underwent a CT). Forty-two participants (2.1%) had confirmed lung cancer, 34 (1.7%) at baseline and 8 (0.4%) at the 12-month scan. 28/42 (66.7%) had stage I disease, 36/42 (85.7%) had stage I or II disease. 35/42 (83.3%) had surgical resection. 536 subjects had nodules greater than 50 mm(3) or 5 mm diameter and 41/536 were found to have lung cancer. One further cancer was detected by follow-up of nodules between 15 and 50 mm(3) at 12 months. The baseline estimate for the incremental cost-effectiveness ratio of once-only CT screening, under the UKLS protocol, was £8466 per quality adjusted life year gained (CI £5542 to £12 569). CONCLUSIONS: The UKLS pilot trial demonstrated that it is possible to detect lung cancer at an early stage and deliver potentially curative treatment in over 80% of cases. Health economic analysis suggests that the intervention would be cost effective-this needs to be confirmed using data on observed lung cancer mortality reduction. TRIAL REGISTRATION: ISRCTN 78513845.

Chronic Aspergillosis of the Lungs: Unravelling the Terminology and Radiology.

UNLABELLED: The propensity for Aspergillus spp. to cause lung disease has long been recognised but the satisfactory classification of these disorders is challenging. The problems caused by invasive disease in severely neutropenic patients, saprophytic infection of pre-existing fibrotic cavities and allergic reactions to Aspergillus are well documented. In contrast, a more chronic form of Aspergillus-related lung disease that has the potential to cause significant morbidity and mortality is under-reported. The symptoms of this form of Aspergillus infection may be non-specific and the radiologist may be the first to suspect a diagnosis of chronic pulmonary aspergillosis. The current review considers the classification conundrums in diseases caused by Aspergillus spp. and discusses the typical clinical and radiological profile of patients with chronic pulmonary aspergillosis. KEY POINTS: • The classification of Aspergillus -related lung disease is mired in confusion. • The chronic form of Aspergillus infection is associated with significant morbidity and mortality. • Progressive consolidation and cavitation with intracavitary material is the radiological hallmark.

Pulmonary light-chain deposition disease: CT and pathology findings in nine patients.

AIM: To review the clinical features of nine patients with pulmonary light-chain deposition disease (LCDD) and record their high-resolution CT (HRCT) and histopathological findings. MATERIALS AND METHODS: Patients with a diagnosis of LCDD on lung biopsy specimen were retrospectively identified. The HRCT characteristics of nodules, cysts, and ancillary findings; change at follow-up; and histopathological findings were documented. RESULTS: Features common to all nine cases were thin-walled cysts. In seven cases, vessels traversing the cysts were identified. The majority of patients (8/9) had at least one pulmonary nodule. There was no zonal predominance of either cysts or nodules. The disease appeared stable in the majority of cases with no serial change in HRCT appearances (5/6 cases with follow-up data, mean duration 29 months). CONCLUSION: To the authors' knowledge, this is the largest series of pulmonary LCDD patients in the literature, and the first systematic assessment of HRCT findings. Pulmonary cysts are a unifying feature, usually with pulmonary nodules, and serial change on HRCT is unusual.

Post-processing applications in thoracic computed tomography.

The rapid evolution of multidetector computed tomography (MDCT) and the introduction of dual-energy CT (DECT) have been paralleled by an unprecedented advancement in post-processing techniques. This has provided complementary methods of two- and three-dimensional visualization of the airways and lung parenchyma, many of which are easily available and not too time-consuming. In addition, advanced imaging has paved the way for methods of quantification of disease that may have a role to play in monitoring chronic obstructive pulmonary disease (COPD) and interstitial lung disease. Computer-aided detection also continues to be explored in lung cancer and pulmonary embolism detection. However, many of these techniques have not yet found widespread adoption in clinical practice. In this article, we review the imaging techniques (used in both single-energy and DECT) that can benefit from post-processing, describe the various post-processing tools available, and consider their clinical application with specific reference to COPD, diffuse lung disease, lung cancer, and pulmonary embolism.

Significance of connective tissue disease features in idiopathic interstitial pneumonia.

In idiopathic interstitial pneumonia (IIP), the significance of connective tissue disease (CTD) features in the absence of a specific CTD diagnosis remains unclear. We studied the clinical and prognostic utility of a diagnosis of undifferentiated CTD (UCTD) in patients with biopsy-proven IIP. IIP patients undergoing surgical lung biopsy (1979-2005) were studied (nonspecific interstitial pneumonia (NSIP), n = 45; idiopathic pulmonary fibrosis, n = 56). UCTD was considered present when serum autoantibodies were present and symptoms or signs suggested CTD. The relationship between UCTD and NSIP histology was evaluated. A clinical algorithm that best predicted NSIP histology was constructed using a priori variables. The prognostic utility of UCTD, and of this algorithm, was evaluated. UCTD was present in 14 (31%) NSIP and seven (13%) IPF patients. UCTD was not associated with a survival benefit. The algorithm predictive of NSIP (OR 10.4, 95% CI 3.21-33.67; p<0.0001) consisted of the absence of typical high-resolution computed tomography (HRCT) features for IPF and 1) a compatible demographic profile (females aged <50 yrs) or 2) Raynaud's phenomenon. In patients with an HRCT scan not typical for IPF, this algorithm predicted improved survival (hazard ratio 0.35, 95% CI 0.14-0.85; p = 0.02) independent of IIP severity. UCTD is associated with NSIP histology. However, the diagnostic and prognostic significance of UCTD in IIP patients remains unclear.

UK Lung Screen (UKLS) nodule management protocol: modelling of a single screen randomised controlled trial of low-dose CT screening for lung cancer.

The UK Lung Screen (UKLS) is a randomised controlled trial of the use of low-dose multidetector CT for lung cancer screening. It completed the Health Technology Appraisal (HTA)-funded feasibility stage in October 2009 and the pilot UKLS will be initiated in early 2011. The pilot will randomise 4000 subjects to either low-dose CT screening or no screening. The full study, due to start in September 2012, if progression criteria are met, will randomise a further 28,000 subjects from seven centres in the UK. Subjects will be selected if they have sufficient risk of developing lung cancer according to the Liverpool Lung Project risk model. The UKLS employs the 'Wald Single Screen Design', which was modelled in the UKLS feasibility study. This paper describes the modelling of nodule management in UKLS by using volumetric analysis with a single initial screen design and follow-up period of 10 years. This modelling has resulted in the development and adoption of the UKLS care pathway, which will be implemented in the planned CT screening trial in the UK.

Atelectasis and survival after bronchoscopic lung volume reduction for COPD.

Bronchoscopic therapies to reduce lung volumes in chronic obstructive pulmonary disease are intended to avoid the risks associated with lung volume reduction surgery (LVRS) or to be used in patient groups in whom LVRS is not appropriate. Bronchoscopic lung volume reduction (BLVR) using endobronchial valves to target unilateral lobar occlusion can improve lung function and exercise capacity in patients with emphysema. The benefit is most pronounced in, though not confined to, patients where lobar atelectasis has occurred. Few data exist on their long-term outcome. 19 patients (16 males; mean±sd forced expiratory volume in 1 s 28.4±11.9% predicted) underwent BLVR between July 2002 and February 2004. Radiological atelectasis was observed in five patients. Survival data was available for all patients up to February 2010. None of the patients in whom atelectasis occurred died during follow-up, whereas eight out of 14 in the nonatelectasis group died (Chi-squared p=0.026). There was no significant difference between the groups at baseline in lung function, quality of life, exacerbation rate, exercise capacity (shuttle walk test or cycle ergometry) or computed tomography appearances, although body mass index was significantly higher in the atelectasis group (21.6±2.9 versus 28.4±2.9 kg·m(-2); p<0.001). The data in the present study suggest that atelectasis following BLVR is associated with a survival benefit that is not explained by baseline differences.

Increased epithelial permeability in pulmonary fibrosis in relation to disease progression.

Epithelial injury contributes to pathogenesis in idiopathic pulmonary fibrosis (IPF) but its role in the interstitial lung disease (ILD) of systemic sclerosis (SSc) is uncertain. We quantified the prognostic significance of inhaled technetium-99m ((99m)Tc)-labelled diethylene triamine pentacetate (DTPA) pulmonary clearance, a marker of the extent of epithelial injury, in both diseases. Baseline (99m)Tc-DTPA pulmonary clearance was evaluated retrospectively in patients with SSc-ILD (n = 168) and IPF (n = 97) against mortality and disease progression. In SSc-ILD, the rapidity of total clearance (hazard ratio (HR) 1.02, 95% CI 1.01-1.03; p = 0.001) and the presence of abnormally rapid clearance (HR 2.10; 95% CI 1.25-3.53; p = 0.005) predicted a shorter time to forced vital capcity (FVC) decline, independent of disease severity. These associations were robust in both mild and severe disease. By contrast, in IPF, delayed clearance of the slow component, an expected consequence of honeycomb change, was an independent predictor of a shorter time to FVC decline (HR 1.01, 95% CI 1.00-1.02; p<0.01). Epithelial injury should be incorporated in pathogenetic models in SSc-ILD. By contrast, outcome is not linked to the overall extent of epithelial injury in IPF, apart from abnormalities ascribable to honeycombing, suggesting that core pathogenetic events may be more spatially focal in that disease.

Optimal scoring of serial change on chest radiography in sarcoidosis.

BACKGROUND: The optimal means of quantifying change on chest radiography in sarcoidosis is uncertain. In current guidelines, the role of serial measurement of carbon-monoxide diffusing capacity (DLco) remains undefined and the prevalence of discordance between serial chest radiographic change and pulmonary function tends is unknown. OBJECTIVE: To identify and explore key uncertainties in the monitoring of sarcoidosis by serial pulmonary function tests and chest radiography. DESIGN: 354 patients with sarcoidosis and concurrent tests (chest radiography and PFTs within three months at baseline, two years and/or four years) were studied. Chest radiographs were assessed by two radiologists for changes in stage and disease extent. Radiographic change and pulmonary function trends were quantified and compared. RESULTS: Change in radiographic extent of lung disease was always more frequent than change in stage (p < 0.0001) and there was poor agreement between change in stage and change in radiographic extent (Kw = 0.21 at two years; Kw = 0.23 at four years). Change in disease extent on chest radiography was linked to PFT trends on analysis of variance (p < 0.0005 for FEV1, FVC, DLco), whereas change in radiographic stage was not. Changes in gas transfer were often isolated or discordant with other serial data. Discordance between pulmonary function data and chest radiographic data was observed in 50% of cases. CONCLUSIONS: Change in radiographic extent is more applicable to routine monitoring in sarcoidosis than change in radiographic stage. In future guidelines, the role of serial gas transfer estimation and reconciliation of divergent chest radiographic and functional trends might usefully be addressed.

Marginal decline in forced vital capacity is associated with a poor outcome in idiopathic pulmonary fibrosis.

In therapeutic studies in idiopathic pulmonary fibrosis (IPF), the low prevalence of significant change in pulmonary functional tests (PFTs) has been a major constraint. The prognostic value of "marginal" changes in PFTs in IPF and fibrotic non-specific interstitial pneumonia (NSIP) was evaluated. In patients with biopsy-proven IPF (n = 84) and NSIP (n = 72), forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (D( L,CO)) trends at 6 months were categorised as "significant" (FVC >10%; D(L,CO) >15%) or "marginal" (FVC 5-10%; D(L,CO) 7.5-15%). Proportional hazards analysis and time-dependent receiver operating characteristic methodology were used to examine PFT trends against mortality. In IPF, reductions in FVC were significant in 22 cases (26%) and marginal in 19 cases (23%). Mortality was higher in patients with a significant decline in FVC (hazard ratio (HR) 2.80, 95% CI 1.54-5.06; p<0.001) and those with a marginal decline in FVC (HR 2.31, 95% CI 1.19-4.50; p = 0.01) than in those with stable disease. Progression-free survival was lower when the decline in FVC was marginal than in stable disease (HR 2.34, 95% CI 1.19-4.60; p = 0.01). Marginal changes in D(L,CO) in IPF and marginal changes in FVC and D (L,CO) in fibrotic NSIP did not provide useful prognostic information. Marginal change in FVC in IPF denotes a poor outcome. These findings are applicable to clinical practice and to the selection of patients with more progressive disease for therapeutic studies.

Pulmonary vascular resistance predicts early mortality in patients with diffuse fibrotic lung disease and suspected pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH) is associated with a poor prognosis in diffuse lung disease (DLD). A study was undertaken to compare the prognostic significance of invasive and non-invasive parameters in patients with DLD and suspected PH. METHODS: Hospital records of consecutive patients with DLD undergoing right heart catheterisation (RHC) were reviewed (n = 66). Mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR) and non-invasive variables were examined against early (within 12 months) and overall mortality. A priori thresholds were examined against early mortality. Relationships between mPAP, PVR and non-invasive markers were assessed. RESULTS: Fifty patients had PH on RHC (mean (SD) mPAP 33.5 (11.8) mm Hg, PVR 5.9 (4.3) Wood units (WU)). Raised PVR was strongly associated with early mortality (odds ratio (OR) 1.30; 95% confidence interval (CI) 1.11 to 1.52; p = 0.001), with PVR > or = 6.23 WU being the optimal threshold after adjustment for age, gender, composite physiological index (CPI) and diagnosis of idiopathic pulmonary fibrosis (OR 11.09; 95% CI 2.54 to 48.36; p = 0.001). Early mortality was linked, albeit less strongly, to right ventricular dilation at echocardiography, but not to other non-invasive variables or mPAP. Overall mortality was most strongly associated with increasing CPI levels. Correlations between PVR and non-invasive variables were moderate (R(2) <0.32), improving little following construction of a multivariate index which did not itself predict mortality. CONCLUSION: In severe DLD, early mortality is strongly linked to increased PVR but not to other RHC or non-invasive variables. These findings suggest that the threshold for RHC in severe DLD should be low, enabling prioritisation of aggressive treatment including lung transplantation.

Mortality in bronchiectasis: a long-term study assessing the factors influencing survival.

There is little literature about the mortality associated with bronchiectasis. The aim of the present study was to investigate factors affecting mortality in patients with bronchiectasis. In total, 91 patients were examined for aetiology, pulmonary function tests, high-resolution computed tomography, sputum microbiology and quality of life scores and were then followed over 13 yrs. Overall, 29.7% of the patients died. On multivariate analysis, age, St George's Respiratory Questionnaire activity score, Pseudomonas aeruginosa infection, total lung capacity (TLC), residual volume/TLC and the transfer factor coefficient were all independently associated with mortality. In patients with moderate to severe bronchiectasis, mortality is associated with a degree of restrictive and obstructive disease, poor gas transfer and chronic pseudomonas infection. These features should guide future research into disease progression, and identify those patients needing intensive treatment.

Use of intravenous cyclophosphamide in known or suspected, advanced non-specific interstitial pneumonia.

BACKGROUND: In severe, progressive interstitial lung disease (ILD), specific diagnosis is often difficult, and treatment therefore empirical. An effective, rapidly acting, well-tolerated therapy is desirable. This study reviews the tolerability and efficacy of i.v. cyclophosphamide in known or suspected non-specific interstitial pneumonia (NSIP) following the introduction of an i.v. cyclophosphamide protocol. METHODS: Records of 54 patients with biopsy-proven (n = 7) or suspected NSIP, based on clinico-radiological consensus (n = 47), receiving i.v. cyclophosphamide over 2004-6 were reviewed (excluding systemic sclerosis). Lung-function trends over six months were evaluated, and comparative analysis of paired pulmonary-function before and after the start of therapy was performed. RESULTS: IV cyclophosphamide was well tolerated, with two withdrawals from therapy, and four deaths, not directly related to treatment. IV cyclophosphamide was associated with disease stability at six-months. Despite having severe, progressive disease, patients receiving i.v. cyclophosphamide had stable lung function at six months. A greater therapeutic response was associated with coexistent HRCT abnormalities indicative of organizing pneumonia. In 22 patients with paired pulmonary-function tests, pulmonary function trends were significantly improved (p = 0.03) and change in DLco differed significantly (p < 0.0001), following cyclophosphamide treatment. CONCLUSION: In the empirical treatment of advanced, rapidly progressive known or suspected NSIP, i.v. cyclophosphamide is a well tolerated, rapidly acting immunosuppressant, associated with improvement or stability in most cases.

Computed tomography signs of pulmonary hypertension: old and new observations.

Pulmonary hypertension (PH) has a poor prognosis. It may be idiopathic or develop secondary to various cardiac and respiratory disorders. The diagnosis of PH is challenging because its signs and symptoms are non-specific and there is no completely reliable non-invasive test for its detection. Most patients with suspected PH or with the non-specific symptoms of PH will undergo computed tomography (CT) as part of their diagnostic work-up and, therefore, it is important for radiologists to be aware of the CT signs that may suggest the diagnosis. This article will review the numerous CT signs of PH describing their individual strengths and weaknesses, and discuss how they may be applied in clinical practice.

Incidentally detected small pulmonary nodules on CT.

The widespread use of multidetector computed tomography for imaging of the chest has lead to a significant increase in the number of incidentally detected pulmonary nodules. The significance of these nodules is often uncertain and further investigations may be required. This article will review the spectrum of imaging appearances of small pulmonary nodules, and highlight the few features that allow confident characterization of a nodule as benign or malignant; current guidelines for the management of incidentally detected nodules will also be discussed.

Can HRCT be used as a marker of airway remodelling in children with difficult asthma?

BACKGROUND: Whole airway wall thickening on high resolution computed tomography (HRCT) is reported to parallel thickening of the bronchial epithelial reticular basement membrane (RBM) in adult asthmatics. A similar relationship in children with difficult asthma (DA), in whom RBM thickening is a known feature, may allow the use of HRCT as a non-invasive marker of airway remodelling. We evaluated this relationship in children with DA. METHODS: 27 children (median age 10.5 [range 4.1-16.7] years) with DA, underwent endobronchial biopsy from the right lower lobe and HRCT less than 4 months apart. HRCTs were assessed for bronchial wall thickening (BWT) of the right lower lobe using semi-quantitative and quantitative scoring techniques. The semi-quantitative score (grade 0-4) was an overall assessment of BWT of all clearly identifiable airways in HRCT scans. The quantitative score (BWT %; defined as [airway outer diameter - airway lumen diameter]/airway outer diameter x100) was the average score of all airways visible and calculated using electronic endpoint callipers. RBM thickness in endobronchial biopsies was measured using image analysis. 23/27 subjects performed spirometry and the relationships between RBM thickness and BWT with airflow obstruction evaluated. RESULTS: Median RBM thickness in endobronchial biopsies was 6.7(range 4.6-10.0) microm. Median qualitative score for BWT of the right lower lobe was 1(range 0-1.5) and quantitative score was 54.3 (range 48.2-65.6)%. There was no relationship between RBM thickness and BWT in the right lower lobe using either scoring technique. No relationship was found between FEV1 and BWT or RBM thickness. CONCLUSION: Although a relationship between RBM thickness and BWT on HRCT has been found in adults with asthma, this relationship does not appear to hold true in children with DA.

Thin-section CT of the lungs: eye-tracking analysis of the visual approach to reading tiled and stacked display formats.

OBJECTIVE: To use eye-tracking analysis to identify the differences in approach to and efficiency of reading thin-section CT of the lungs presented tiled and stacked soft-copy displays. MATERIALS AND METHODS: Four chest radiologists read 16 thin-section CT examinations displayed in either a tiled (four images at once) or stacked (full screen cine) format. Eye-movements were recorded and analysed in terms of movement type; saccade distance (classified by the calculated range of useful peripheral vision), number of fixations, duration and direction of gaze-comparison of the areas of the images viewed. RESULTS: Cases presented in stacked format were read quicker than when presented in tiled format with a greater fixation frequency (5 fixations versus 4.5 fixations points per 100 data points; p<0.001) and a greater proportion of short saccades (97% versus 94%; p<0.005). The consistency with which the observers viewed equivalent areas of the scan images in different cases was greater when viewing in stacked format (mean kappa 0.45 versus 0.36; p<0.05) suggesting a more systematic approach to reading. CONCLUSION: Eye-tracking data demonstrates why thin-section CT examinations of the lungs are read more efficiently when displayed in a stack as opposed to a tiled format.

Combined Pulmonary Fibrosis and Emphysema in Scleroderma-Related Lung Disease Has a Major Confounding Effect on Lung Physiology and Screening for Pulmonary Hypertension.

OBJECTIVE: To assess the prevalence of combined pulmonary fibrosis and emphysema (CPFE) in systemic sclerosis (SSc) patients with interstitial lung disease (ILD) and the effect of CPFE on the pulmonary function tests used to evaluate the severity of SSc-related ILD and the likelihood of pulmonary hypertension (PH). METHODS: High-resolution computed tomography (HRCT) scans were obtained in 333 patients with SSc-related ILD and were evaluated for the presence of emphysema and the extent of ILD. The effects of emphysema on the associations between pulmonary function variables and the extent of SSc-related ILD as visualized on HRCT and echocardiographic evidence of PH were quantified. RESULTS: Emphysema was present in 41 (12.3%) of the 333 patients with SSc-related ILD, in 26 (19.7%) of 132 smokers, and in 15 (7.5%) of 201 lifelong nonsmokers. When the extent of fibrosis was taken into account, emphysema was associated with significant additional differences from the expected values for diffusing capacity for carbon monoxide (DLco) (average reduction of 24.1%; P < 0.0005), and the forced vital capacity (FVC)/DLco ratio (average increase of 34.8%; P < 0.0005) but not FVC. These effects were identical in smokers and nonsmokers. Multivariate analysis showed that the presence of emphysema had a greater effect than echocardiographically determined PH on the FVC/DLco ratio, regardless of whether it was analyzed as a continuous variable or using a threshold value of 1.6 or 2.0. CONCLUSION: Among patients with SSc-related ILD, emphysema is sporadically present in nonsmokers and is associated with a low pack-year history in smokers. The confounding effect of CPFE on measures of gas exchange has major implications for the construction of screening algorithms for PH in patients with SSc-related ILD.