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Proceedings Paper

Variation of quantitative emphysema measurements from CT scans
Author(s): Brad M. Keller; Anthony P. Reeves; Claudia I. Henschke; R. Graham Barr; David F. Yankelevitz
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Paper Abstract

Emphysema is a lung disease characterized by destruction of the alveolar air sacs and is associated with long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema, and several measures have been introduced for the quantification of the extent of disease. In this paper we compare these measures for repeatability over time. The measures of interest in this study are emphysema index, mean lung density, histogram percentile, and the fractal dimension. To allow for direct comparisons, the measures were normalized to a 0-100 scale. These measures have been computed for a set of 2,027 scan pairs in which the mean interval between scans was 1.15 years (σ: 93 days). These independent pairs were considered with respect to three different scanning conditions (a) 223 pairs where both were scanned with a 5 mm slice thickness protocol, (b) 695 with the first scanned with the 5 mm protocol and the second with a 1.25 mm protocol, and (c) 1109 pairs scanned both times using a 1.25 mm protocol. We found that average normalized emphysema index and histogram percentiles scores increased by 5.9 and 11 points respectively, while the fractal dimension showed stability with a mean difference of 1.2. We also found, a 7 point bias introduced for emphysema index under condition (b), and that the fractal dimension measure is least affected by scanner parameter changes.

Paper Details

Date Published: 1 April 2008
PDF: 8 pages
Proc. SPIE 6915, Medical Imaging 2008: Computer-Aided Diagnosis, 69152I (1 April 2008); doi: 10.1117/12.770844
Show Author Affiliations
Brad M. Keller, Cornell Univ. (United States)
Anthony P. Reeves, Cornell Univ. (United States)
Claudia I. Henschke, Cornell Univ. (United States)
R. Graham Barr, College of Physicians and Surgeons, Columbia Univ. (United States)
David F. Yankelevitz, Weill Medical College of Cornell Univ. (United States)


Published in SPIE Proceedings Vol. 6915:
Medical Imaging 2008: Computer-Aided Diagnosis
Maryellen L. Giger; Nico Karssemeijer, Editor(s)

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