Title
Active relearning for robust supervised training of emphysema patterns.
Abstract
Radiologists are adept at recognizing the character and extent of lung parenchymal abnormalities in computed tomography (CT) scans. However, the inconsistent differential diagnosis due to subjective aggregation necessitates the exploration of automated classification based on supervised or unsupervised learning. The robustness of supervised learning depends on the training samples. Towards optimizing emphysema classification, we introduce a physician-in-the-loop feedback approach to minimize ambiguity in the selected training samples. An experienced thoracic radiologist selected 412 regions of interest (ROIs) across 15 datasets to represent 124, 129, 139 and 20 training samples of mild, moderate, severe emphysema and normal appearance, respectively. Using multi-view (multiple metrics to capture complementary features) inductive learning, an ensemble of seven un-optimized support vector models (SVM) each based on a specific metric was constructed in less than 6 s. The training samples were classified using seven SVM models and consensus labels were created using majority voting. In the active relearning phase, the ensemble-expert label conflicts were resolved by the expert. The efficacy and generality of active relearning feedback was assessed in the optimized parameter space of six general purpose classifiers across the seven dissimilarity metrics. The proposed just-in-time active relearning feedback with un-optimized SVMs yielded 15 % increase in classification accuracy and 25 % reduction in the number of support vectors. The average improvement in accuracy of six classifiers in their optimized parameter space was 21 %. The proposed cooperative feedback method enhances the quality of training samples used to construct automated classification of emphysematous CT scans. Such an approach could lead to substantial improvement in quantification of emphysema.
Year
DOI
Venue
2014
10.1007/s10278-014-9686-z
J. Digital Imaging
Keywords
Field
DocType
Emphysema,Supervised classification,Support Vector Machines (SVM),Active relearning,Training sample cleaning
General purpose,Computer science,Robustness (computer science),Unsupervised learning,Artificial intelligence,Computed tomography,Supervised training,Majority rule,Computer vision,Pattern recognition,Support vector machine,Supervised learning,Machine learning
Journal
Volume
Issue
ISSN
27
4
1618-727X
Citations 
PageRank 
References 
0
0.34
17
Authors
5
Name
Order
Citations
PageRank
Sushravya Raghunath112.85
Rajagopalan Srinivasan268379.21
Ronald A Karwoski3247.43
Brian J Bartholmai43311.91
Richard A. Robb5645238.12