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Main Authors: Low, Zhen Xuen Brandon, Zhang, Rory, Min, Hang, Pham, William, Vivash, Lucy, Moses, Jasmine, Lynch, Miranda, Dorfman, Karina, Marotta, Cassandra, Koh, Shaun, Bunyamin, Jacob, Rowsthorn, Ella, Jarema, Alex, Peiris, Himashi, Chen, Zhaolin, Shultz, Sandy R., Wright, David K., Kong, Dexiao, Naismith, Sharon L., O'Brien, Terence J., Xia, Ying, Law, Meng, Sinclair, Benjamin
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.20256
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author Low, Zhen Xuen Brandon
Zhang, Rory
Min, Hang
Pham, William
Vivash, Lucy
Moses, Jasmine
Lynch, Miranda
Dorfman, Karina
Marotta, Cassandra
Koh, Shaun
Bunyamin, Jacob
Rowsthorn, Ella
Jarema, Alex
Peiris, Himashi
Chen, Zhaolin
Shultz, Sandy R.
Wright, David K.
Kong, Dexiao
Naismith, Sharon L.
O'Brien, Terence J.
Xia, Ying
Law, Meng
Sinclair, Benjamin
author_facet Low, Zhen Xuen Brandon
Zhang, Rory
Min, Hang
Pham, William
Vivash, Lucy
Moses, Jasmine
Lynch, Miranda
Dorfman, Karina
Marotta, Cassandra
Koh, Shaun
Bunyamin, Jacob
Rowsthorn, Ella
Jarema, Alex
Peiris, Himashi
Chen, Zhaolin
Shultz, Sandy R.
Wright, David K.
Kong, Dexiao
Naismith, Sharon L.
O'Brien, Terence J.
Xia, Ying
Law, Meng
Sinclair, Benjamin
contents Enlarged perivascular spaces (PVS) are increasingly recognized as biomarkers of cerebral small vessel disease, Alzheimer's disease, stroke, and aging-related neurodegeneration. However, manual segmentation of PVS is time-consuming and subject to moderate inter-rater reliability, while existing automated deep learning models have moderate performance and typically fail to generalize across diverse clinical and research MRI datasets. We adapted MedNeXt-L-k5, a Transformer-inspired 3D encoder-decoder convolutional network, for automated PVS segmentation. Two models were trained: one using a homogeneous dataset of 200 T2-weighted (T2w) MRI scans from the Human Connectome Project-Aging (HCP-Aging) dataset and another using 40 heterogeneous T1-weighted (T1w) MRI volumes from seven studies across six scanners. Model performance was evaluated using internal 5-fold cross validation (5FCV) and leave-one-site-out cross validation (LOSOCV). MedNeXt-L-k5 models trained on the T2w images of the HCP-Aging dataset achieved voxel-level Dice scores of 0.88+/-0.06 (white matter, WM), comparable to the reported inter-rater reliability of that dataset, and the highest yet reported in the literature. The same models trained on the T1w images of the HCP-Aging dataset achieved a substantially lower Dice score of 0.58+/-0.09 (WM). Under LOSOCV, the model had voxel-level Dice scores of 0.38+/-0.16 (WM) and 0.35+/-0.12 (BG), and cluster-level Dice scores of 0.61+/-0.19 (WM) and 0.62+/-0.21 (BG). MedNeXt-L-k5 provides an efficient solution for automated PVS segmentation across diverse T1w and T2w MRI datasets. MedNeXt-L-k5 did not outperform the nnU-Net, indicating that the attention-based mechanisms present in transformer-inspired models to provide global context are not required for high accuracy in PVS segmentation.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20256
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle MedNet-PVS: A MedNeXt-Based Deep Learning Model for Automated Segmentation of Perivascular Spaces
Low, Zhen Xuen Brandon
Zhang, Rory
Min, Hang
Pham, William
Vivash, Lucy
Moses, Jasmine
Lynch, Miranda
Dorfman, Karina
Marotta, Cassandra
Koh, Shaun
Bunyamin, Jacob
Rowsthorn, Ella
Jarema, Alex
Peiris, Himashi
Chen, Zhaolin
Shultz, Sandy R.
Wright, David K.
Kong, Dexiao
Naismith, Sharon L.
O'Brien, Terence J.
Xia, Ying
Law, Meng
Sinclair, Benjamin
Computer Vision and Pattern Recognition
Artificial Intelligence
Enlarged perivascular spaces (PVS) are increasingly recognized as biomarkers of cerebral small vessel disease, Alzheimer's disease, stroke, and aging-related neurodegeneration. However, manual segmentation of PVS is time-consuming and subject to moderate inter-rater reliability, while existing automated deep learning models have moderate performance and typically fail to generalize across diverse clinical and research MRI datasets. We adapted MedNeXt-L-k5, a Transformer-inspired 3D encoder-decoder convolutional network, for automated PVS segmentation. Two models were trained: one using a homogeneous dataset of 200 T2-weighted (T2w) MRI scans from the Human Connectome Project-Aging (HCP-Aging) dataset and another using 40 heterogeneous T1-weighted (T1w) MRI volumes from seven studies across six scanners. Model performance was evaluated using internal 5-fold cross validation (5FCV) and leave-one-site-out cross validation (LOSOCV). MedNeXt-L-k5 models trained on the T2w images of the HCP-Aging dataset achieved voxel-level Dice scores of 0.88+/-0.06 (white matter, WM), comparable to the reported inter-rater reliability of that dataset, and the highest yet reported in the literature. The same models trained on the T1w images of the HCP-Aging dataset achieved a substantially lower Dice score of 0.58+/-0.09 (WM). Under LOSOCV, the model had voxel-level Dice scores of 0.38+/-0.16 (WM) and 0.35+/-0.12 (BG), and cluster-level Dice scores of 0.61+/-0.19 (WM) and 0.62+/-0.21 (BG). MedNeXt-L-k5 provides an efficient solution for automated PVS segmentation across diverse T1w and T2w MRI datasets. MedNeXt-L-k5 did not outperform the nnU-Net, indicating that the attention-based mechanisms present in transformer-inspired models to provide global context are not required for high accuracy in PVS segmentation.
title MedNet-PVS: A MedNeXt-Based Deep Learning Model for Automated Segmentation of Perivascular Spaces
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2508.20256