Automatic detect lung node with deep learning in segmentation and imbalance data labeling

In this study, a novel method with the U-Net-based network architecture, 2D U-Net, is employed to segment the position of lung nodules, which are an early symptom of lung cancer and have a high probability of becoming a carcinoma, especially when a lung nodule is bigger than 15 mm2. A serious problem of considering deep learning for all medical images is imbalanced labeling between foreground and background. The lung nodule is the foreground which accounts for a lower percentage in a whole image. The evaluation function adopted in this study is dice coefficient loss, which is usually used in image segmentation tasks. The proposed pre-processing method in this study is to use complementary labeling as the input in U-Net. With this method, the labeling is swapped. The no-nodule position is labeled. And the position of the nodule becomes non-labeled. The result shows that the proposal in this study is efficient in a small quantity of data. This method, complementary labeling could be used in a small data quantity scenario. With the use of ROI segmentation model in the data pre-processing, the results of lung nodule detection can be improved a lot as shown in the experiments.

Automated summary

This study employs a novel method utilizing the 2D U-Net network architecture to segment lung nodule positions, addressing the issue of imbalanced labeling between foreground and background in medical images. By using dice coefficient loss as the evaluation function and complementary labeling pre-processing method, the detection of lung nodules is significantly improved, especially in scenarios with small data quantities.