In Rheumatology (Oxford, England)
OBJECTIVES : Nailfold capillaroscopy is key to timely diagnosis of systemic sclerosis (SSc), but is often not used in rheumatology clinics because the images are difficult to interpret. We aimed to develop and validate a fully automated image analysis system to fill this gap.
METHODS : We mimicked the image interpretation strategies of SSc experts, using deep learning networks to detect each capillary in the distal row of vessels and make morphological measurements. We combined measurements from multiple fingers to give a subject-level probability of SSc.We trained the system using high-resolution images from 111 subjects (Group A) and tested on images from subjects not in the training set: 132 imaged at high-resolution (Group B); 66 imaged with a low-cost digital microscope (Group C). Roughly half of each group had confirmed SSc, half were healthy controls or had primary Raynaud's phenomenon ('normal'). We also estimated the performance of SSc experts.
RESULTS : We compared automated SSc probabilities with the known clinical status of patients (SSc versus 'normal'), generating receiver operating characteristic curves (ROCs). For Group B, the area under the ROC (AUC) was 97% [94% - 99%] (median [90% confidence interval]), with equal sensitivity/specificity 91% [86% - 95%]. For Group C, AUC was 95% [88% - 99%], with equal sensitivity/specificity 89% [82% - 95%]. SSc expert consensus achieved sensitivity 82%, specificity 73%.
CONCLUSION : Fully automated analysis using deep learning can achieve diagnostic performance at least as good as SSc experts, and is sufficiently robust to work with low-cost digital microscope images.
Gurunath Bharathi Praveen, Berks Michael, Dinsdale Graham, Murray Andrea, Manning Joanne, Wilkinson Sarah, Cutolo Maurizio, Smith Vanessa, Herrick Ariane L, Taylor Chris J
2023-Jan-18
Systemic sclerosis, automated analysis, deep learning, nailfold capillaroscopy
