Texture-based Quantification of Centrilobular Emphysema and Centrilobular Nodularity in Longitudinal CT Scans of Current and Former Smokers

Abstract

Rationale and Objectives The effect of smoking cessation on centrilobular emphysema (CLE) and centrilobular nodularity (CN), two manifestations of smoking-related lung injury on CT images, has not been clarified. The objective of this study is to leverage texture analysis to investigate differences in extent of CLE and CN between current and former smokers. Materials and Methods Chest CT scans from 350 current smokers, 401 former smokers, and 25 control subjects were obtained from the multicenter COPDGene Study, a HIPAA-compliant study approved by the institutional review board of each participating clinical study center. Additionally, for 215 of these subjects, a follow-up CT scan was obtained approximately five years later. For each CT scan, 5000 circular regions-of-interest (ROIs) of 35-pixel diameter were randomly selected throughout the lungs. The patterns present in each ROI were summarized by fifty computer-extracted texture features. A logistic regression classifier was leveraged to classify each ROI as normal lung, CLE, or CN, and differences in the percentages of normal lung, CLE, and CN by study group were assessed. Results Former smokers had significantly more CLE (p < 0.01) but less CN (p < 0.001) than current smokers, even after adjustment for important covariates such as patient age, GOLD stage, smoking history, FEV1, gas trapping, and scanner model. Among patients with longitudinal CT scans, continued smoking led to a slight increase in CLE (p = 0.13), whereas sustained abstinence from smoking led to further reduction in CN (p < 0.05). Conclusion The proposed texture-based approach quantifies the extent of CN and CLE with high precision. Differences in smoking-related lung disease between longitudinal scans of current and former smokers suggest that CN may be reversible upon smoking cessation.

CT Texture Analysis: Definitions, Applications, Biologic Correlates, and Challenges

“…In addition to the oncologic applications, there are a number of emerging nononcologic applications of CTTA, including assessing lung disease such as fibrosis and emphysema (11,(70)(71)(72)(73), assessing hepatic fibrosis (Fig 13) (13,74) or risk for hepatic failure after resection (9), assessing abdominal aortic aneurysms for risk of rupture (75), and evaluating osseous trabecular texture to detect anorexia nervosa (76). The number of studies is too limited to draw conclusions about the value of CTTA in assessing diffuse disease of the lungs and liver.…”

Texture analysis of the liver at MDCT for assessing hepatic fibrosis

“…This technique has been most intensely studied in oncologic applications, and has shown association with pathologic features and clinical outcomes in a variety of tumor types [18][19][20][21][22][23][24][25][26][27][28][29][30][31]. Some non-oncologic applications are being evaluated, with several groups using texture analysis to assess emphysema and fibrosis in the lung [32,33]. One small series using CT texture analysis to evaluate hepatic fibrosis found that texture parameters showed some ability to discriminate between stages of fibrosis, but the results were not very convincing [34].…”

Entwicklungen in der Analyse von Tumorheterogenität in computertomografischen Aufnahmen

“…Neben den genannten Anwendungen der CT-Texturheterogenitätsanalyse im onkologischen Setting sind auch nicht maligne Erkrankungen ein möglicher Anwendungsbereich. So konnten beispielsweise strukturelle Lungengerüstveränderungen wie Emphysem und Fibrosegrade mittels 3D-CT-Texturanalyse robust charakterisiert werden [24,25]. Es besteht zudem potentiell die Möglichkeit nicht-invasive Diagnostiken auszuweiten, beispielsweise im Rahmen der Evaluation fibrotischer Leberparenchymveränderungen anhand von kontrastmittelgestützten CT-Scans [26].…”