Segmentation of spinal rootlets across MRI contrasts with RootletSeg

Fuente: arXiv
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Main Authors: Krejci, Katerina, Chmelik, Jiri, Bedard, Sandrine, Eippert, Falk, Horn, Ulrike, Callot, Virginie, Cohen-Adad, Julien, Valosek, Jan
Format: Preprint
Published: 2025
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author Krejci, Katerina
Chmelik, Jiri
Bedard, Sandrine
Eippert, Falk
Horn, Ulrike
Callot, Virginie
Cohen-Adad, Julien
Valosek, Jan
author_facet Krejci, Katerina
Chmelik, Jiri
Bedard, Sandrine
Eippert, Falk
Horn, Ulrike
Callot, Virginie
Cohen-Adad, Julien
Valosek, Jan
contents Purpose: To develop a deep learning method for the automatic segmentation of spinal nerve rootlets on various MRI scans. Material and Methods: This retrospective study included MRI scans from two open-access and one private dataset, consisting of 3D isotropic 3T TSE T2-weighted (T2w) and 7T MP2RAGE (T1-weighted [T1w] INV1 and INV2, and UNIT1) MRI scans. A deep learning model, RootletSeg, was developed to segment C2-T1 dorsal and ventral spinal rootlets. Training was performed on 76 scans and testing on 17 scans. The Dice score was used to compare the model performance with an existing open-source method. Spinal levels derived from RootletSeg segmentations were compared with vertebral levels defined by intervertebral discs using Bland-Altman analysis. Results: The RootletSeg model developed on 93 MRI scans from 50 healthy adults (mean age, 28.70 years $\pm$ 6.53 [SD]; 28 [56%] males, 22 [44%] females) achieved a mean $\pm$ SD Dice score of 0.67 $\pm$ 0.09 for T1w-INV2, 0.65 $\pm$ 0.11 for UNIT1, 0.64 $\pm$ 0.08 for T2w, and 0.62 $\pm$ 0.10 for T1w-INV1 contrasts. Spinal-vertebral level correspondence showed a progressively increasing rostrocaudal shift, with Bland-Altman bias ranging from 0.00 to 8.15 mm (median difference between level midpoints). Conclusion: RootletSeg accurately segmented C2-T1 spinal rootlets across MRI contrasts, enabling the determination of spinal levels directly from MRI scans. The method is open-source and can be used for a variety of downstream analyses, including lesion classification, neuromodulation therapy, and functional MRI group analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2509_16255
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Segmentation of spinal rootlets across MRI contrasts with RootletSeg
Krejci, Katerina
Chmelik, Jiri
Bedard, Sandrine
Eippert, Falk
Horn, Ulrike
Callot, Virginie
Cohen-Adad, Julien
Valosek, Jan
Tissues and Organs
Image and Video Processing
Medical Physics
Purpose: To develop a deep learning method for the automatic segmentation of spinal nerve rootlets on various MRI scans. Material and Methods: This retrospective study included MRI scans from two open-access and one private dataset, consisting of 3D isotropic 3T TSE T2-weighted (T2w) and 7T MP2RAGE (T1-weighted [T1w] INV1 and INV2, and UNIT1) MRI scans. A deep learning model, RootletSeg, was developed to segment C2-T1 dorsal and ventral spinal rootlets. Training was performed on 76 scans and testing on 17 scans. The Dice score was used to compare the model performance with an existing open-source method. Spinal levels derived from RootletSeg segmentations were compared with vertebral levels defined by intervertebral discs using Bland-Altman analysis. Results: The RootletSeg model developed on 93 MRI scans from 50 healthy adults (mean age, 28.70 years $\pm$ 6.53 [SD]; 28 [56%] males, 22 [44%] females) achieved a mean $\pm$ SD Dice score of 0.67 $\pm$ 0.09 for T1w-INV2, 0.65 $\pm$ 0.11 for UNIT1, 0.64 $\pm$ 0.08 for T2w, and 0.62 $\pm$ 0.10 for T1w-INV1 contrasts. Spinal-vertebral level correspondence showed a progressively increasing rostrocaudal shift, with Bland-Altman bias ranging from 0.00 to 8.15 mm (median difference between level midpoints). Conclusion: RootletSeg accurately segmented C2-T1 spinal rootlets across MRI contrasts, enabling the determination of spinal levels directly from MRI scans. The method is open-source and can be used for a variety of downstream analyses, including lesion classification, neuromodulation therapy, and functional MRI group analysis.
title Segmentation of spinal rootlets across MRI contrasts with RootletSeg
topic Tissues and Organs
Image and Video Processing
Medical Physics
url https://arxiv.org/abs/2509.16255