Vegas-Sanchez-Ferrero G, Washko G, Rahaghi FN, Ledesma-Carbayo MJ, Estépar RSJ. DERIVATION OF A TEST STATISTIC FOR EMPHYSEMA QUANTIFICATION.
Proc IEEE Int Symp Biomed Imaging 2016;
2016:1269-1273. [PMID:
27974952 PMCID:
PMC5153356 DOI:
10.1109/isbi.2016.7493498]
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Abstract
Density masking is the de-facto quantitative imaging phenotype for emphysema that is widely used by the clinical community. Density masking defines the burden of emphysema by a fixed threshold, usually between -910 HU and -950 HU, that has been experimentally validated with histology. In this work, we formalized emphysema quantification by means of statistical inference. We show that a non-central Gamma is a good approximation for the local distribution of image intensities for normal and emphysema tissue. We then propose a test statistic in terms of the sample mean of a truncated non-central Gamma random variable. Our results show that this approach is well-suited for the detection of emphysema and superior to standard density masking. The statistical method was tested in a dataset of 1337 samples obtained from 9 different scanner models in subjects with COPD. Results showed an increase of 17% when compared to the density masking approach, and an overall accuracy of 94.09%.
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