Rationale and Objectives: Breast segmentation using the U-net architecture was implemented and tested in independent validation datasets to quantify fibroglandular tissue volume in breast MRI. Materials and Methods: Two datasets were used. The training set was MRI of 286 patients with unilateral breast cancer. The segmentation was done on the contralateral normal breasts. The ground truth for the breast and fibroglandular tissue (FGT) was obtained by using a template-based segmentation method. The U-net deep learning algorithm was implemented to analyze the training set, and the final model was obtained using 10-fold cross-validation. The independent validation set was MRI of 28 normal volunteers acquired using four different MR scanners. Dice Similarity Coefficient (DSC), voxel-based accuracy, and Pearson's correlation were used to evaluate the performance. Results: For the 10-fold cross-validation in the initial training set of 286 patients, the DSC range was 0.83–0.98 (mean 0.95 ± 0.02) for breast and 0.73–0.97 (mean 0.91 ± 0.03) for FGT; and the accuracy range was 0.92–0.99 (mean 0.98 ± 0.01) for breast and 0.87–0.99 (mean 0.97 ± 0.01) for FGT. For the entire 224 testing breasts of the 28 normal volunteers in the validation datasets, the mean DSC was 0.86 ± 0.05 for breast, 0.83 ± 0.06 for FGT; and the mean accuracy was 0.94 ± 0.03 for breast and 0.93 ± 0.04 for FGT. The testing results for MRI acquired using four different scanners were comparable. Conclusion: Deep learning based on the U-net algorithm can achieve accurate segmentation results for the breast and FGT on MRI. It may provide a reliable and efficient method to process large number of MR images for quantitative analysis of breast density.
Bibliographical noteFunding Information:
This study is supported in part by NIH R01 CA127927 R21 CA170955, R21 CA208938, and R03 CA136071 and a Basic Science Research Program through the National Research Foundation of Korea (NRF, Korea) funded by the Ministry of Education (NRF-2017R1D1A1B03035995).
This study is supported in part by NIH R01 CA127927 R21 CA170955 , R21 CA208938 , and R03 CA136071 and a Basic Science Research Program through the National Research Foundation of Korea (NRF, Korea) funded by the Ministry of Education (NRF-2017 R1D1A1B03035995 ).
© 2019 The Association of University Radiologists
All Science Journal Classification (ASJC) codes
- Radiology Nuclear Medicine and imaging