Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks

The quantification of new or enlarged lesions from follow-up MRI scans is an important surrogate of clinical disease activity in patients with multiple sclerosis (MS). Not only is manual segmentation time consuming, but inter-rater variability is high. Currently, only a few fully automated methods a...

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Main Authors: Julia Krüger, Roland Opfer, Nils Gessert, Ann-Christin Ostwaldt, Praveena Manogaran, Hagen H. Kitzler, Alexander Schlaefer, Sven Schippling
Format: Article
Language:English
Published: Elsevier 2020-01-01
Series:NeuroImage: Clinical
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2213158220302825
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author Julia Krüger
Roland Opfer
Nils Gessert
Ann-Christin Ostwaldt
Praveena Manogaran
Hagen H. Kitzler
Alexander Schlaefer
Sven Schippling
author_facet Julia Krüger
Roland Opfer
Nils Gessert
Ann-Christin Ostwaldt
Praveena Manogaran
Hagen H. Kitzler
Alexander Schlaefer
Sven Schippling
author_sort Julia Krüger
collection DOAJ
description The quantification of new or enlarged lesions from follow-up MRI scans is an important surrogate of clinical disease activity in patients with multiple sclerosis (MS). Not only is manual segmentation time consuming, but inter-rater variability is high. Currently, only a few fully automated methods are available. We address this gap in the field by employing a 3D convolutional neural network (CNN) with encoder-decoder architecture for fully automatic longitudinal lesion segmentation.Input data consist of two fluid attenuated inversion recovery (FLAIR) images (baseline and follow-up) per patient. Each image is entered into the encoder and the feature maps are concatenated and then fed into the decoder. The output is a 3D mask indicating new or enlarged lesions (compared to the baseline scan). The proposed method was trained on 1809 single point and 1444 longitudinal patient data sets and then validated on 185 independent longitudinal data sets from two different scanners. From the two validation data sets, manual segmentations were available from three experienced raters, respectively. The performance of the proposed method was compared to the open source Lesion Segmentation Toolbox (LST), which is a current state-of-art longitudinal lesion segmentation method.The mean lesion-wise inter-rater sensitivity was 62%, while the mean inter-rater number of false positive (FP) findings was 0.41 lesions per case. The two validated algorithms showed a mean sensitivity of 60% (CNN), 46% (LST) and a mean FP of 0.48 (CNN), 1.86 (LST) per case. Sensitivity and number of FP were not significantly different (p < 0.05) between the CNN and manual raters.New or enlarged lesions counted by the CNN algorithm appeared to be comparable with manual expert ratings. The proposed algorithm seems to outperform currently available approaches, particularly LST. The high inter-rater variability in case of manual segmentation indicates the complexity of identifying new or enlarged lesions. An automated CNN-based approach can quickly provide an independent and deterministic assessment of new or enlarged lesions from baseline to follow-up scans with acceptable reliability.
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spelling doaj.art-23911af55b254b5fb632e45f1589d55d2022-12-21T23:16:27ZengElsevierNeuroImage: Clinical2213-15822020-01-0128102445Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networksJulia Krüger0Roland Opfer1Nils Gessert2Ann-Christin Ostwaldt3Praveena Manogaran4Hagen H. Kitzler5Alexander Schlaefer6Sven Schippling7jung diagnostics GmbH, Hamburg, Germany; Corresponding author.jung diagnostics GmbH, Hamburg, GermanyInstitute of Medical Technology, Hamburg University of Technology, Germanyjung diagnostics GmbH, Hamburg, GermanyNeuroimmunology and Multiple Sclerosis Research, Department of Neurology, University Hospital Zurich and University of Zurich, Switzerland; Department of Information Technology and Electrical Engineering, Swiss Federal Institute of Technology, Zurich, SwitzerlandInstitute of Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus, Technische Universität Dresden, GermanyInstitute of Medical Technology, Hamburg University of Technology, GermanyNeuroimmunology and Multiple Sclerosis Research, Department of Neurology, University Hospital Zurich and University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and Federal Institute of Technology (ETH), Zurich, SwitzerlandThe quantification of new or enlarged lesions from follow-up MRI scans is an important surrogate of clinical disease activity in patients with multiple sclerosis (MS). Not only is manual segmentation time consuming, but inter-rater variability is high. Currently, only a few fully automated methods are available. We address this gap in the field by employing a 3D convolutional neural network (CNN) with encoder-decoder architecture for fully automatic longitudinal lesion segmentation.Input data consist of two fluid attenuated inversion recovery (FLAIR) images (baseline and follow-up) per patient. Each image is entered into the encoder and the feature maps are concatenated and then fed into the decoder. The output is a 3D mask indicating new or enlarged lesions (compared to the baseline scan). The proposed method was trained on 1809 single point and 1444 longitudinal patient data sets and then validated on 185 independent longitudinal data sets from two different scanners. From the two validation data sets, manual segmentations were available from three experienced raters, respectively. The performance of the proposed method was compared to the open source Lesion Segmentation Toolbox (LST), which is a current state-of-art longitudinal lesion segmentation method.The mean lesion-wise inter-rater sensitivity was 62%, while the mean inter-rater number of false positive (FP) findings was 0.41 lesions per case. The two validated algorithms showed a mean sensitivity of 60% (CNN), 46% (LST) and a mean FP of 0.48 (CNN), 1.86 (LST) per case. Sensitivity and number of FP were not significantly different (p < 0.05) between the CNN and manual raters.New or enlarged lesions counted by the CNN algorithm appeared to be comparable with manual expert ratings. The proposed algorithm seems to outperform currently available approaches, particularly LST. The high inter-rater variability in case of manual segmentation indicates the complexity of identifying new or enlarged lesions. An automated CNN-based approach can quickly provide an independent and deterministic assessment of new or enlarged lesions from baseline to follow-up scans with acceptable reliability.http://www.sciencedirect.com/science/article/pii/S2213158220302825Multiple sclerosisLesion activityConvolutional neural networkU-netLesion segmentation
spellingShingle Julia Krüger
Roland Opfer
Nils Gessert
Ann-Christin Ostwaldt
Praveena Manogaran
Hagen H. Kitzler
Alexander Schlaefer
Sven Schippling
Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
NeuroImage: Clinical
Multiple sclerosis
Lesion activity
Convolutional neural network
U-net
Lesion segmentation
title Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
title_full Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
title_fullStr Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
title_full_unstemmed Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
title_short Fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3D convolutional neural networks
title_sort fully automated longitudinal segmentation of new or enlarged multiple sclerosis lesions using 3d convolutional neural networks
topic Multiple sclerosis
Lesion activity
Convolutional neural network
U-net
Lesion segmentation
url http://www.sciencedirect.com/science/article/pii/S2213158220302825
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