A Learning Approach for Informative-Frame Selection in US Rheumatology Images

Rheumatoid arthritis (RA) is an autoimmune disorder that causes pain, swelling and stiffness in joints. Nowadays, ultrasound (US) has undergone an increasing role in RA screening since it is a powerful tool to assess disease activity. However, obtaining a good quality US frame is a tricky operator dependent procedure. For this reason, the purpose of this paper is to present a strategy to the automatic selection of informative US rheumatology images by means of Convolutional Neural Networks (CNNs). The proposed method is based on VGG16 and Inception V3 CNNs, which are fine tuned to classify 214 balanced metacarpal head US images (75% used for training and 25% used for testing). A repeated 3 fold cross validation for each CNN was performed. The best results were achieved with VGG16 (area under the curve = 90%). These results support the possibility of applying this method in the actual clinical practice for supporting the diagnostic process and helping young residents’ training.