Article
Quantitative airway assessment on computed tomography in patients with alpha1-antitrypsin deficiency.
Center for Pulmonary Functional Imaging, Brigham and Women's Hospital, Boston, Massachusetts, USA.
COPD Journal of Chronic Obstructive Pulmonary Disease (impact factor:
1.79).
12/2009;
6(6):468-77.
DOI:10.3109/15412550903341521
Source: PubMed
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Article: Detection of emphysema progression in alpha 1-antitrypsin deficiency using CT densitometry; methodological advances.
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ABSTRACT: Computer tomography (CT) densitometry is a potential tool for detecting the progression of emphysema but the optimum methodology is uncertain. The level of inspiration affects reproducibility but the ability to adjust for this variable is facilitated by whole lung scanning methods. However, emphysema is frequently localised to sub-regions of the lung and targeted densitometric sampling may be more informative than whole lung assessment. Emphysema progression over a 2-year interval was assessed in 71 patients (alpha 1-antitrypsin deficiency with PiZ phenotype) with CT densitometry, using the 15th percentile point (Perc15) and voxel index (VI) -950 Hounsfield Units (HU) and -910 HU (VI -950 and -910) on whole lung, limited single slices, and apical, central and basal thirds. The relationship between whole lung densitometric progression (DeltaCT) and change in CT-derived lung volume (DeltaCTVol) was characterised, and adjustment for lung volume using statistical modelling was evaluated. CT densitometric progression was statistically significant for all methods. DeltaCT correlated with DeltaCTVol and linear regression indicated that nearly one half of lung density loss was secondary to apparent hyperinflation. The most accurate measure was obtained using a random coefficient model to adjust for lung volume and the greatest progression was detected by targeted sampling of the middle third of the lung. Progressive hyperinflation may contribute significantly to loss of lung density, but volume effects and absolute tissue loss can be identified by statistical modelling. Targeted sampling of the middle lung region using Perc15 appears to be the most robust measure of emphysema progression.Respiratory research 02/2008; 9:21. · 3.36 Impact Factor -
Article: New concepts in the pathobiology of chronic obstructive pulmonary disease.
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ABSTRACT: Chronic obstructive pulmonary disease (COPD) is characterized by an abnormal persistent inflammatory response to cigarette smoke. This noxious insult leads to emphysema and airway remodeling, manifested by squamous and mucous metaplasia of the epithelium, smooth muscle hypertrophy, and airway wall fibrosis. These pathologic abnormalities interact synergistically to cause progressive airflow obstruction. Although it has been accepted that the spectrum of COPD is vast, the reasons for the development of different phenotypes from the same exposure to cigarette smoke have not been determined. Furthermore, it is becoming increasingly clear that airways disease and emphysema often coexist in many patients, even with a clear clinical phenotype of either emphysema or chronic bronchitis. Recent studies have focused on the nature of the inflammatory response to cigarette smoke, the inflammatory cell lines responsible for COPD pathogenesis, and new biomarkers for disease activity and progression. New cytokines are being discovered, and the complex interactions among them are being unraveled. The inflammatory biomarker that has received the most attention is C-reactive protein, but new ones that have caught our attention are interleukin (IL)-6, tumor necrosis factor-alpha, IL-8, and IL-10. Further research should focus on how these new concepts in lung inflammation interact to cause the various aspects of COPD pathology.Proceedings of the American Thoracic Society 06/2008; 5(4):478-85. -
Article: Validation of computed tomographic lung densitometry for monitoring emphysema in alpha1-antitrypsin deficiency.
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ABSTRACT: Lung densitometry derived from computed tomographic images offers an opportunity to quantify emphysema non-invasively, but a pathological standard cannot be applied to validate its use in longitudinal monitoring studies. Consequently, forced expiratory volume in 1 second (FEV1) remains the standard against which new methods must be judged. We related progression of densitometry (15th percentile point and voxel index, threshold -950 Hounsfield units) to disease stage and FEV1 decline in two studies of subjects with alpha1-antitrypsin deficiency (PiZ). Consistency of progression, measured using densitometry and FEV1, was assessed in relation to disease stage in a 2 year study of 74 subjects grouped according to the FEV1 criteria employed in the GOLD guidelines. In the second study of a subgroup of subjects with extended data (n=34), summary statistics were applied to measurements performed annually over 3 years and the rate of progression of densitometry was related to FEV1 decline. The progression of percentile point was consistent across a wide spectrum of disease severity, but voxel index progression varied in association with disease stage (p=0.004). In the second study, FEV1 decline correlated with progression of lung densitometry (percentile point: rS=0.527, p=0.001; voxel index: rS=-0.398, p=0.012). 15th percentile point is a more consistent measure of lung density loss across a wide range of physiological impairment than voxel index. However, both methods are valid for use in longitudinal and interventional studies in which emphysema is the major outcome target.Thorax 07/2006; 61(6):485-90. · 6.84 Impact Factor
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Keywords
1)-antitrypsin deficiency
52 patients
airflow limitation
airway disease
airway progressed distally
computed tomography
Correlations
CT-based airway indices
distal airways
low attenuation area percent
lower
lower lung
luminal area
predominant component
quantitative airway measurements
severe alpha
significant correlations
Spearman rank correlation test
wall area percent
weak correlations
