Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm

One essential step in radiotherapy treatment planning is the organ at risk of segmentation in Computed Tomography (CT). Many recent studies have focused on several organs such as the lung, heart, esophagus, trachea, liver, aorta, kidney, and prostate. However, among the above organs, the esophagus i...

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Main Authors: Minh-Trieu Tran, Soo-Hyung Kim, Hyung-Jeong Yang, Guee-Sang Lee, In-Jae Oh, Sae-Ryung Kang
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/21/13/4556
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author Minh-Trieu Tran
Soo-Hyung Kim
Hyung-Jeong Yang
Guee-Sang Lee
In-Jae Oh
Sae-Ryung Kang
author_facet Minh-Trieu Tran
Soo-Hyung Kim
Hyung-Jeong Yang
Guee-Sang Lee
In-Jae Oh
Sae-Ryung Kang
author_sort Minh-Trieu Tran
collection DOAJ
description One essential step in radiotherapy treatment planning is the organ at risk of segmentation in Computed Tomography (CT). Many recent studies have focused on several organs such as the lung, heart, esophagus, trachea, liver, aorta, kidney, and prostate. However, among the above organs, the esophagus is one of the most difficult organs to segment because of its small size, ambiguous boundary, and very low contrast in CT images. To address these challenges, we propose a fully automated framework for the esophagus segmentation from CT images. The proposed method is based on the processing of slice images from the original three-dimensional (3D) image so that our method does not require large computational resources. We employ the spatial attention mechanism with the atrous spatial pyramid pooling module to locate the esophagus effectively, which enhances the segmentation performance. To optimize our model, we use group normalization because the computation is independent of batch sizes, and its performance is stable. We also used the simultaneous truth and performance level estimation (STAPLE) algorithm to reach robust results for segmentation. Firstly, our model was trained by k-fold cross-validation. And then, the candidate labels generated by each fold were combined by using the STAPLE algorithm. And as a result, Dice and Hausdorff Distance scores have an improvement when applying this algorithm to our segmentation results. Our method was evaluated on SegTHOR and StructSeg 2019 datasets, and the experiment shows that our method outperforms the state-of-the-art methods in esophagus segmentation. Our approach shows a promising result in esophagus segmentation, which is still challenging in medical analyses.
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spelling doaj.art-824412cc51c14b2cb7d86d8bfa86b8192023-11-22T02:51:05ZengMDPI AGSensors1424-82202021-07-012113455610.3390/s21134556Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE AlgorithmMinh-Trieu Tran0Soo-Hyung Kim1Hyung-Jeong Yang2Guee-Sang Lee3In-Jae Oh4Sae-Ryung Kang5Department of Artificial Intelligence Convergence, Chonnam National University, 77 Yongbong-ro, Gwangju 500757, KoreaDepartment of Artificial Intelligence Convergence, Chonnam National University, 77 Yongbong-ro, Gwangju 500757, KoreaDepartment of Artificial Intelligence Convergence, Chonnam National University, 77 Yongbong-ro, Gwangju 500757, KoreaDepartment of Artificial Intelligence Convergence, Chonnam National University, 77 Yongbong-ro, Gwangju 500757, KoreaDepartment of Internal Medicine, Chonnam National University Medical School and Hwasun Hospital, Hwasun 58128, KoreaDepartment of Nuclear Medicine, Chonnam National University Medical School and Hwasun Hospital, Hwasun 58128, KoreaOne essential step in radiotherapy treatment planning is the organ at risk of segmentation in Computed Tomography (CT). Many recent studies have focused on several organs such as the lung, heart, esophagus, trachea, liver, aorta, kidney, and prostate. However, among the above organs, the esophagus is one of the most difficult organs to segment because of its small size, ambiguous boundary, and very low contrast in CT images. To address these challenges, we propose a fully automated framework for the esophagus segmentation from CT images. The proposed method is based on the processing of slice images from the original three-dimensional (3D) image so that our method does not require large computational resources. We employ the spatial attention mechanism with the atrous spatial pyramid pooling module to locate the esophagus effectively, which enhances the segmentation performance. To optimize our model, we use group normalization because the computation is independent of batch sizes, and its performance is stable. We also used the simultaneous truth and performance level estimation (STAPLE) algorithm to reach robust results for segmentation. Firstly, our model was trained by k-fold cross-validation. And then, the candidate labels generated by each fold were combined by using the STAPLE algorithm. And as a result, Dice and Hausdorff Distance scores have an improvement when applying this algorithm to our segmentation results. Our method was evaluated on SegTHOR and StructSeg 2019 datasets, and the experiment shows that our method outperforms the state-of-the-art methods in esophagus segmentation. Our approach shows a promising result in esophagus segmentation, which is still challenging in medical analyses.https://www.mdpi.com/1424-8220/21/13/4556esophagus segmentationdeep learningspatial attention module
spellingShingle Minh-Trieu Tran
Soo-Hyung Kim
Hyung-Jeong Yang
Guee-Sang Lee
In-Jae Oh
Sae-Ryung Kang
Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
Sensors
esophagus segmentation
deep learning
spatial attention module
title Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
title_full Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
title_fullStr Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
title_full_unstemmed Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
title_short Esophagus Segmentation in CT Images via Spatial Attention Network and STAPLE Algorithm
title_sort esophagus segmentation in ct images via spatial attention network and staple algorithm
topic esophagus segmentation
deep learning
spatial attention module
url https://www.mdpi.com/1424-8220/21/13/4556
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AT gueesanglee esophagussegmentationinctimagesviaspatialattentionnetworkandstaplealgorithm
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