Automatic segmentation of hepatocellular carcinoma on dynamic contrast-enhanced MRI based on deep learning

Abstract

Objective: Precise hepatocellular carcinoma (HCC) detection is crucial for clinical management. While studies focus on CT-based automatic algorithms, there is a rareness of research on automatic detection based on dynamic contrast enhanced (DCE) MRI. This study is to develop an automatic detection and segmentation deep learning model for HCC using DCE. 
Approach: DCE images acquired from 2016 to 2021 were retrospectively collected. Then, 382 patients (301 male; 81 female) with 466 lesions pathologically confirmed were included and divided into an 80% training-validation set and a 20% independent test set. For external validation, 51 patients (42 male; 9 female) in another hospital from 2018 to 2021 were included. The U-net architecture was modified to accommodate multi-phasic DCE input. The model was trained with the training-validation set using five-fold cross-validation, and furtherly evaluated with the independent test set using comprehensive metrics for segmentation and detection performance. The proposed automatic segmentation model consisted of five main steps: phase registration, automatic liver region extraction using a pre-trained model, automatic HCC lesion segmentation using the multi-phasic deep learning model, ensemble of five-fold predictions, and post-processing using connected component analysis to enhance the performance to refine predictions and eliminate false positives. 
Main results: The proposed model achieved a mean dice similarity coefficient (DSC) of 0.81±0.11, a sensitivity of 94.41±15.50%, a precision of 94.19±17.32%, and 0.14±0.48 false positive lesions per patient in the independent test set. The model detected 88% (80/91) HCC lesions in the condition of DSC>0.5, and the DSC per tumor was 0.80±0.13. In the external set, the model detected 92% (58/62) lesions with 0.12±0.33 false positives per patient, and the DSC per tumor was 0.75±0.10. 
Significance: This study developed an automatic detection and segmentation deep learning model for HCC using DCE, which yielded promising post-processed results in accurately identifying and delineating HCC lesions.