1,721,081 research outputs found
False negative results in lung cancer screening - Evidence and Controversies
No full textIdentifying false negative cases is an important quality metric in lung cancer screening but these have been infrequently and variably reported in previous studies. Although as a proportion of all screening participants, false negative cases are uncommon, such cases may constitute a significant proportion of all lung cancers diagnosed (up to 15%) within a screening programme. This article reviews the impact and causes of false negative lung cancer screening tests, including those related to radiological evaluation, nodule management protocols, and management decisions made by multidisciplinary teams. Following a review of data from international screening studies, this article discusses controversies within the screening literature surrounding the definition and classification of a false negative lung cancer screening test, and how data on false negative rates should be captured and recorded. Challenges, such as avoiding overly cautious surveillance of lung nodules whilst also minimizing over-diagnosis and investigation of indolent or benign lesions, are considered. Finally, the advantages and disadvantages of different approaches to dealing with false negative results in lung cancer screening are discussed
Method for minimizing observer variation for the quantitation of high-resolution computed tomographic signs of lung disease.
No full textOBJECTIVES: This study aimed to describe a method of reducing interobserver variation associated with the visual quantitation of high-resolution computed tomographic (HRCT) signs of airways and interstitial lung disease (ILD).
METHODS: The HRCT scans of 2 cohorts of patients with airways disease (n = 144) and ILD (n = 109) were evaluated by 2 observers. Selected signs of airways disease were evaluated: (1) bronchial wall thickness and (2) the extent of the decreased attenuation. In the ILD group, the total extent of disease was scored. These 3 HRCT signs were scored by 2 observers independently using a standard method. The observers rescored the CT scans with a new scoring system (continuous learning method, CLM).
RESULTS: Observer agreement for CT signs was superior for CLM: bronchial wall thickness κw increased from 0.51 to 0.76; for decreased attenuation, κw increased from 0.34 to 0.81; and for ILD extent, κw increased from 0.53 to 0.87.
CONCLUSIONS: The CLM reduces noise from observer variation in studies that require visual quantitation of HRCT signs of lung disease
Chronic hypersensitivity pneumonitis: high resolution computed tomography patterns and pulmonary function indices as prognostic determinants.
No full textOBJECTIVES: To investigate high resolution computed tomography (HRCT) and pulmonary function indices (PFTs) for determining prognosis in patients with chronic fibrotic hypersensitivity pneumonitis (CHP).
METHODS: Case records, PFTs (FEV(1), FVC and DLco) and HRCTs of ninety-two patients with chronic hypersensitivity pneumonitis were evaluated. HRCT studies were scored by two observers for total disease extent, ground-glass opacification, fine and coarse reticulation, microcystic and macrocystic honeycombing, centrilobular emphysema and consolidation. Traction bronchiectasis within each pattern was graded. Using Cox proportional hazards regression models the prognostic strength of individual HRCT patterns and pulmonary function test variables were determined.
RESULTS: There were forty two deaths during the study period. Increasing severity of traction bronchiectasis was the strongest predictor of mortality (HR 1.10, P < 0.001, 95%CI 1.04-1.16). Increasing global interstitial disease extent (HR 1.02, P = 0.02, 95%CI 1.00-1.03), microcystic honeycombing (HR 1.09, P = 0.019, 95%CI 1.01-1.17) and macrocystic honeycombing (HR 1.06, P < 0.01, 95%CI 1.01-1.10) were also independent predictors of mortality. In contrast, no individual PFT variable was predictive of mortality once HRCT patterns were accounted for.
CONCLUSION: HRCT patterns, in particular, severity of traction bronchiectasis and extent of honeycombing are superior to pulmonary function tests for predicting mortality in patients with CHP.
KEY POINTS: • HRCT is increasingly used to assess chronic fibrotic hypersensitivity pneumonitis. • HRCT patterns are superior to pulmonary function tests for predicting mortality. • Extensive traction bronchiectasis strongly predicts poor survival in chronic hypersensitivity pneumonitis
Connective tissue disease related fibrotic lung disease: high resolution computed tomographic and pulmonary function indices as prognostic determinants.
No full textTo determine high resolution computed tomography (HRCT) patterns and pulmonary function indices which are associated with increased mortality in patients with connective tissue disease related fibrotic lung disease (CTD-FLD).HRCTs from 168 patients with CTD-FLD were scored by 2 observers for a variety of HRCT patterns and traction bronchiectasis. A radiological diagnosis of usual interstitial pneumonia (UIP), fibrotic non-specific interstitial pneumonia (NSIP) or indeterminate was also assigned. Using Cox regression analysis, associations with mortality were identified. Honeycombing and traction bronchiectasis scores were converted to binary absence/presence scores and also tested. A subgroup analysis of patients with biopsy material (n=51) was performed by classifying patients according to radiological and histopathological diagnoses, as concordant UIP, discordant UIP and fibrotic NSIP. The prognostic separation of this classification was also evaluated.Severity of traction bronchiectasis (HR 1.10, p=0.001, 95\% CIs 1.04 to 1.17), increasing extent of honeycombing (HR 1.08, p=0.021, 95\% CI 1.03 to 1.13) and reduction in DLco (HR 0.97, p=0.013, 95\% CI 0.95 to 0.99) were independently associated with increased mortality. Interobserver agreement and prognostic strength were higher for binary traction bronchiectasis scores (weighted κ (κw)=0.69, HR 4.00, p=0.001, 95\%CI 1.19 to 13.38), than binary honeycombing scores (κw=0.50, HR 2.87, p=0.022, 95\% CI 1.53 to 5.43). The radiological-histopathological classification was strongly associated with increased mortality (HR 2.74, p<0.001, 95\% CI 1.57 to 4.77) and patients with discordant UIP had a better prognosis than concordant UIP but worse prognosis than fibrotic NSIP.Severity of traction bronchiectasis, extent of honeycombing and DLco are strongly associated with mortality in CTD-FLD. Interobserver agreement for traction bronchiectasis is higher than for honeycombing. In CTD-FLD, radiological diagnosis has survival implications in biopsy proven UIP
Evaluation of computed tomography (CT) features of lung volume alteration in diffuse lung disease
Full text linkBackground
Lung volume change in idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD) may impact upon fissures and diaphragm. CT measures designed to capture displacement of these structures may play a role in prognostication.
Methods
The cohorts studied were: baseline IPF with 273 patients (205 males, median age 67), serial IPF with 81 patients (66 males, median age 67) and baseline COPD with 150 patients (76 males, median age 64). Selected HRCT signs included oblique fissure retraction distance (OFRD), anterior junctional distance (AJD), sagittal lung height (SLH) and superior mediastinal level (SML). The disease extent on HRCT in IPF was scored by two observers. In COPD cohort, an automated application (Syngovia) was used for disease quantification. The CT measurements were validated against PFTs and mortality using linear regression and proportional hazards analyses.
Results
There were 203 baseline and 58 serial deaths in IPF cohorts with median survival 26 and 17 months respectively. In baseline IPF and COPD, SLH was the strongest determinant of TLC% and RV/TLC% respectively (R2 =0.28, P<0.005 and R2 =0.1 respectively, P<0.0005). In baseline IPF data, a combination of SLH, AJD and OFRD improved correlation with TLC% (R2=0.42, P<0.0005), predicting mortality independent of visual scores (HR=97, CI 0.96,0.99, P<0.0005). In serial IPF, annual AJD change predicted mortality (HR 0.97, 95% CI 0.95, 0.98; P<0.0005) better than annual FVC change (HR 0.98, 95% CI 0.96, 0.99; p<0.0005). In COPD, there was significant difference in patients with or without upper-zone predominant disease for OFRD and SML (P=0.04 and P<0.0005 respectively).
Conclusion
The CT signs of lung volume change correlate moderately with PFTs in COPD and IPF; being independent predictors of mortality when adjusted for visual scores in IPF and providing signal on zonal distribution of disease in COPD. In IPF, AJD proved to be a better predictor of outcome compared to FVC sequentially.Open Acces
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
CT findings in fibrotic lung disease: reassessment of the reliability and utility of the status quo in diagnosis and outcome
No full textHypersensitivity pneumonitis is a pulmonary disease thought to result from an inappropriate immune response to inhaled organic antigens. Whilst historically classified by the duration of symptoms, a categorisation based on the presence of pulmonary fibrosis is now favoured, as this is related to disease course and response to treatment. Furthermore, the presence of fibrosis invokes a different radiological differential diagnosis.
In addition to this paradigm shift, several short comings of the literature in fibrotic lung disease require scrutiny. CT guidelines use the presence of ‘mosaic attenuation’ to distinguish fibrotic hypersensitivity pneumonitis (FHP) from its closest radiological differential, idiopathic pulmonary fibrosis (IPF), but these are unvalidated and indeed untested. The presence of increased proportion of lymphocytes on bronchoalveolar lavage (BAL) is used to support a diagnosis of FHP, but this technique has never been validated with regards to diagnostic utility or prognosis. Finally, the majority of publications examining CT signs of fibrotic lung disease are subject to incorporation bias, whereby the CT data under study is also used to define cases.
A re-examination of the CT signs in three separate cohorts of patients with fibrotic lung diseases is presented. Firstly, undertaking a detailed examination of the various forms of mosaic attenuation, against high confidence diagnoses FHP and IPF agnostic to CT data, in a test and validation cohort. A large prospective cohort of patients undergoing BAL who have a ‘reasonable differential’ for FHP, defined without CT data, is also examined.
An overlooked CT sign of mosaic attenuation, the ‘headcheese’ sign, is found to be highly specific for a diagnosis of FHP, as opposed to IPF, and is validated in an external cohort. BAL lymphocyte proportion is shown to relate to disease extent, and BAL lymphocytosis is found to be prognostic in fibrotic lung disease.Open Acces
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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