TY - JOUR
T1 - Quantifying Heterogeneity in Emphysema from High-Resolution Computed Tomography. A Lung Tissue Research Consortium Study.
AU - Yilmaz, Cuneyt
AU - Dane, Dan M.
AU - Patel, Nova C.
AU - Hsia, Connie C W
N1 - Funding Information:
Supported by National Heart, Lung, and Blood Institute grant 1 RO3 HL097010 (C.Y.). The Lung Tissue Research Consortium was supported by the National Center for Research Resources 1 UL1 RR024150 .
PY - 2013/2
Y1 - 2013/2
N2 - Rationale and Objectives: To quantify spatial distribution of emphysema using high-resolution computed tomography (HRCT), we applied semiautomated analysis with internal attenuation calibration to measure regional air volume, tissue volume, and fractional tissue volume (FTV = tissue/[air + tissue] volume) in well-characterized patients studied by the Lung Tissue Research Consortium (LTRC). Methods: HRCT was obtained at supine end-inspiration and end-expiration, and prone end-inspiration from 31 patients with mild, moderate, severe, or very severe emphysema (stages II-V, forced expiratory volume at 1 second >75%, 51%-75%, 21%-50% and ≤20% predicted, respectively). Control data were from 20 healthy non-smokers (stage I). Each lobe was analyzed separately. Heterogeneity of FTV was assessed from coefficients of variation (CV) within and among lobes, and the kurtosis and skewness of FTV histograms. Results: In emphysema, lobar air volume increased up to 177% above normal except in the right middle lobe. Lobar tissue volume increased up to 107% in mild-moderate stages then normalized in advanced stages. Normally, FTV was up to 82% higher in lower than upper lobes. In mild-moderate emphysema, lobar FTV increased by up to 74% above normal at supine inspiration. In severe emphysema, FTV declined below normal in all lobes and positions in correlation with pulmonary function ( P < .05). Markers of FTV heterogeneity increased steadily with disease stage in correlation with pulmonary function ( P < .05); the pattern is distinct from that seen in interstitial lung disease (ILD). Conclusion: CT-derived biomarkers differentiate the spatial patterns of emphysema distribution and heterogeneity from that in ILD. Early emphysema is associated with elevated tissue volume and FTV, consistent with hyperemia, inflammation or atelectasis.
AB - Rationale and Objectives: To quantify spatial distribution of emphysema using high-resolution computed tomography (HRCT), we applied semiautomated analysis with internal attenuation calibration to measure regional air volume, tissue volume, and fractional tissue volume (FTV = tissue/[air + tissue] volume) in well-characterized patients studied by the Lung Tissue Research Consortium (LTRC). Methods: HRCT was obtained at supine end-inspiration and end-expiration, and prone end-inspiration from 31 patients with mild, moderate, severe, or very severe emphysema (stages II-V, forced expiratory volume at 1 second >75%, 51%-75%, 21%-50% and ≤20% predicted, respectively). Control data were from 20 healthy non-smokers (stage I). Each lobe was analyzed separately. Heterogeneity of FTV was assessed from coefficients of variation (CV) within and among lobes, and the kurtosis and skewness of FTV histograms. Results: In emphysema, lobar air volume increased up to 177% above normal except in the right middle lobe. Lobar tissue volume increased up to 107% in mild-moderate stages then normalized in advanced stages. Normally, FTV was up to 82% higher in lower than upper lobes. In mild-moderate emphysema, lobar FTV increased by up to 74% above normal at supine inspiration. In severe emphysema, FTV declined below normal in all lobes and positions in correlation with pulmonary function ( P < .05). Markers of FTV heterogeneity increased steadily with disease stage in correlation with pulmonary function ( P < .05); the pattern is distinct from that seen in interstitial lung disease (ILD). Conclusion: CT-derived biomarkers differentiate the spatial patterns of emphysema distribution and heterogeneity from that in ILD. Early emphysema is associated with elevated tissue volume and FTV, consistent with hyperemia, inflammation or atelectasis.
KW - CT scan
KW - Coefficient of variation
KW - Fractional tissue volume
KW - Image analysis
KW - Kurtosis
KW - Skewness
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U2 - 10.1016/j.acra.2012.09.013
DO - 10.1016/j.acra.2012.09.013
M3 - Article
C2 - 23122057
AN - SCOPUS:84873521726
SN - 1076-6332
VL - 20
SP - 181
EP - 193
JO - Academic radiology
JF - Academic radiology
IS - 2
ER -