@article {1677611,
	title = {DERIVATION OF A TEST STATISTIC FOR EMPHYSEMA QUANTIFICATION},
	journal = {Proc IEEE Int Symp Biomed Imaging},
	volume = {2016},
	year = {2016},
	month = {2016 Apr},
	pages = {1269-1273},
	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\%.},
	issn = {1945-7928},
	doi = {10.1109/ISBI.2016.7493498},
	author = {Vegas-Sanchez-Ferrero, Gonzalo and Washko, George and Rahaghi, Farbod N and Ledesma-Carbayo, Maria J and R San Jos{\'e} Est{\'e}par}
}