Attention-gated Convolutional Neural Network for Automated Segmentation of Fetal Subplate from MRI.

Poster No:

1656 

Submission Type:

Late-Breaking Abstract Submission 

Authors:

Andrea Gondova1, Milton O. Candela-Leal1, Hyuk Jin Yun1, Sungmin You1, Seungyoon Jeong1, Marisol Aguilar1, P. Ellen Grant1, Kiho Im1

Institutions:

1Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital, Boston, MA

First Author:

Andrea Gondova  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA

Co-Author(s):

Milton O. Candela-Leal  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
Hyuk Jin Yun  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
Sungmin You  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
Seungyoon Jeong  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
Marisol Aguilar  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
P. Ellen Grant  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA
Kiho Im  
Fetal Neonatal Neuroimaging and Developmental Science Center, Boston Children’s Hospital
Boston, MA

Late Breaking Reviewer(s):

Stephanie Forkel, PhD  
Donders Institute for Brain, Cognition, and Behaviour
Nijmegen, Gelderland
Jaehee Kim  
Duksung Women's University
Seoul, 서울특별시
Janaina Mourao-Miranda  
University College London
London, London
Anna Roe, Phd  
Zhejiang University
Hangzhou, Zhejiang

Introduction:

The subplate (SP) is a transient fetal brain structure implicated in numerous developmental processes, including neuronal migration, circuit formation, and early cortical activity, with its alterations linked to neurodevelopmental disorders (Kostović, 2020). While recent advances in fetal MRI enable in vivo SP visualization, automated segmentation ‒ crucial for large-scale, non-invasive studies ‒ remains underexplored compared to other brain structures like the cortical plate (CP) (Dou et al., 2020; Uus et al., 2023). To address this gap, we extend a validated attention-gated U-Net model (Hong et al., 2020), originally developed for CP segmentation, to incorporate SP to facilitate a more comprehensive fetal brain analysis.

Methods:

We analyzed a retrospective multi-site cohort of T2-weighted fetal brain MRI from 134 typically developing fetuses (GW: 27.32 ± 2.67, range: 21.86–31.86). Data processing included brain masking, slice-to-volume registration, alignment to a 31-week template (You et al., 2024), and N4 bias field correction to mitigate scanner variations (Tutison et al., 2010). Fourteen cases were held out for testing, while 120 were used for training and validation (Figure 1a,b). Our approach consisted of an ensemble of three 2D Attention Gated U-Net models trained on axial, coronal, and sagittal planes, with multi-view aggregation and test-time augmentation (MVA-TTA) to improve segmentation stability. A hybrid loss function combining Dice and focal loss was used to enhance boundary delineation (Hong et al., 2020)(Figure 1c).
Supporting Image: Figure1_with_caption.png
 

Results:

Our model demonstrated high segmentation performance, achieving a global Dice score of 0.98 ± 0.015 (mean ± std), Hausdorff distance of 5.36 ± 2.406 voxels, and 1.29 ± 0.929% volumetric change in the test set. Performance was consistent across tissue types. We observed a slight (non-significant) decline increasing gestational age, likely due to evolving tissue contrast and morphology complexity (Figure 2a). Qualitative evaluations showed most segmentation errors at the CP/SP boundary (Figure 2b). Despite these, our method provided sufficient accuracy for volumetric and morphometric SP analyses, significantly reducing the need for extensive manual correction in follow-up studies (data not shown).
Supporting Image: Figure2_with_caption.png
 

Conclusions:

We present an automated deep-learning approach for automated SP segmentation in fetal MRI, expanding existing method for large-scale studies of typical and atypical SP development. While minor manual correction remains necessary, particularly in low-quality scans or complex morphologies at later gestational stages, future improvements could incorporate automated refinement techniques such as conditional random fields (Chen et al., 2021) or hybrid segmentation approaches (Gaset et al., 2024). By reducing reliance on labor-intensive manual segmentation, this work will allow future work that could enhance the study of in utero brain development, advance our understanding of early brain development and detect early biomarker for various clinical populations with adverse neurodevelopmental outcomes.

Lifespan Development:

Normal Brain Development: Fetus to Adolescence 2

Modeling and Analysis Methods:

Methods Development
Segmentation and Parcellation 1

Keywords:

Cortical Layers
Development
Machine Learning
PEDIATRIC
Segmentation
STRUCTURAL MRI

1|2Indicates the priority used for review

Abstract Information

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Please indicate which methods were used in your research:

Structural MRI

For human MRI, what field strength scanner do you use?

1.5T

Which processing packages did you use for your study?

FSL

Provide references using APA citation style.

Chen, S., Sedghi Gamechi, Z., Dubost, F., van Tulder, G., & de Bruijne, M. (2021). An end-to-end approach to segmentation in medical images with CNN and posterior-CRF. Medical image analysis, 76, 102311

Diogo, M. C., Prayer, D., Gruber, G. M., Brugger, P. C., Stuhr, F., Weber, M., Bettelheim, D., & Kasprian, G. (2019). Echo-planar FLAIR Sequence Improves Subplate Visualization in Fetal MRI of the Brain. Radiology, 292(1), 159–169

Dou, H., Karimi, D., Rollins, C.K., Ortinau, C.M., Vasung, L., Velasco-Annis, C., Ouaalam, A., Yang, X., Ni, D., & Gholipour, A. (2020). A Deep Attentive Convolutional Neural Network for Automatic Cortical Plate Segmentation in Fetal MRI. IEEE Transactions on Medical Imaging, 40, 1123-1133.

Gaser Ch., Dahnke R., (2024) CAT faces Python – Combining Deep-Learning with Traditional Segmentation. OHBM 2024 Annual Meeting, Seoul, South Korea.

Hong, J., Yun, H.J., Park, G., Kim, S., Laurentys, C.T., Siqueira, L.C., Tarui, T., Rollins, C.K., Ortinau, C.M., Grant, P.E., Lee, J., & Im, K. (2020). Fetal Cortical Plate Segmentation Using Fully Convolutional Networks With Multiple Plane Aggregation. Frontiers in Neuroscience, 14.

Kostović, I. (2020). The enigmatic fetal subplate compartment forms an early tangential cortical nexus and provides the framework for construction of cortical connectivity. Progress in Neurobiology, 194.

Tustison, N., Avants, B.B., Cook, P.A., Zheng, Y., Egan, A., Yushkevich, P., & Gee, J.C. (2010). N4ITK: Improved N3 Bias Correction. IEEE Transactions on Medical Imaging, 29, 1310-1320.

Uus, A. U., Kyriakopoulou, V., Makropoulos, A., Fukami-Gartner, A., Cromb, D., Davidson, A., Cordero-Grande, L., Price, A. N., Grigorescu, I., Williams, L. Z. J., Robinson, E. C., Lloyd, D., Pushparajah, K., Story, L., Hutter, J., Counsell, S. J., Edwards, A. D., Rutherford, M. A., Hajnal, J. V., & Deprez, M. (2023). BOUNTI: Brain vOlumetry and aUtomated parcellatioN for 3D feTal MRI. eLife 12:RP88818.

You, S., Barba, A.D., Tamayo, V.C., Yun, H.J., Yang, E., Grant, P.E., Im, K., Wu, Z., Zhao, F., Leon, D., Tamayo, C., Yun, H., & Grant, P.E. (2024). Automatic cortical surface parcellation in the fetal brain using attention-gated spherical U-net. Frontiers in Neuroscience, 18.

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