1 code implementation • 2 Apr 2024 • Liam Chalcroft, Ioannis Pappas, Cathy J. Price, John Ashburner
Deep learning-based semantic segmentation in neuroimaging currently requires high-resolution scans and extensive annotated datasets, posing significant barriers to clinical applicability.
1 code implementation • 14 Aug 2023 • Liam Chalcroft, Ruben Lourenço Pereira, Mikael Brudfors, Andrew S. Kayser, Mark D'Esposito, Cathy J. Price, Ioannis Pappas, John Ashburner
Vision transformers are effective deep learning models for vision tasks, including medical image segmentation.
1 code implementation • 27 May 2023 • Guilherme Pombo, Robert Gray, Amy P. K. Nelson, Chris Foulon, John Ashburner, Parashkev Nachev
Here we initiate the application of deep generative neural network architectures to the task of lesion-deficit inference, formulating it as the estimation of an expressive hierarchical model of the joint lesion and deficit distributions conditioned on a latent neural substrate.
1 code implementation • 13 Jun 2022 • Mikael Brudfors, Yael Balbastre, John Ashburner, Geraint Rees, Parashkev Nachev, Sebastien Ourselin, M. Jorge Cardoso
Data used in image segmentation are not always defined on the same grid.
no code implementations • 29 Nov 2021 • Guilherme Pombo, Robert Gray, Jorge Cardoso, Sebastien Ourselin, Geraint Rees, John Ashburner, Parashkev Nachev
The model is intended to synthesise counterfactual training data augmentations for downstream discriminative modelling tasks where fidelity is limited by data imbalance, distributional instability, confounding, or underspecification, and exhibits inequitable performance across distinct subpopulations.
1 code implementation • 19 Nov 2021 • Yu Yan, Yael Balbastre, Mikael Brudfors, John Ashburner
Segmentation of brain magnetic resonance images (MRI) into anatomical regions is a useful task in neuroimaging.
1 code implementation • 24 Aug 2021 • Yaël Balbastre, Ali Aghaeifar, Nadège Corbin, Mikael Brudfors, John Ashburner, Martina F. Callaghan
Conclusion: The proposed methods simplify inter-scan motion correction of $R_1$ maps and are applicable at both 3T and 7T, where a body coil is typically not available.
1 code implementation • 12 Apr 2021 • Mikael Brudfors, Yaël Balbastre, John Ashburner, Geraint Rees, Parashkev Nachev, Sébastien Ourselin, M. Jorge Cardoso
While convolutional neural networks (CNNs) trained by back-propagation have seen unprecedented success at semantic segmentation tasks, they are known to struggle on out-of-distribution data.
1 code implementation • 11 Mar 2021 • Fabio S. Ferreira, Agoston Mihalik, Rick A. Adams, John Ashburner, Janaina Mourao-Miranda
In synthetic data, GFA uncovered the underlying shared and specific factors and predicted correctly the non-observed data modalities in complete and incomplete data sets.
1 code implementation • 2 Feb 2021 • Yael Balbastre, Mikael Brudfors, Michela Azzarito, Christian Lambert, Martina F. Callaghan, John Ashburner
Instead, we propose a probabilistic generative (forward) model of the entire dataset, which is formulated and inverted to jointly recover (log) parameter maps with a well-defined probabilistic interpretation (e. g., maximum likelihood or maximum a posteriori).
no code implementations • 3 Jun 2020 • Mikael Brudfors, Yaël Balbastre, Guillaume Flandin, Parashkev Nachev, John Ashburner
We describe a diffeomorphic registration algorithm that allows groups of images to be accurately aligned to a common space, which we intend to incorporate into the SPM software.
1 code implementation • 28 May 2020 • Yaël Balbastre, Mikael Brudfors, Michela Azzarito, Christian Lambert, Martina F. Callaghan, John Ashburner
Quantitative magnetic resonance imaging (qMRI) derives tissue-specific parameters -- such as the apparent transverse relaxation rate R2*, the longitudinal relaxation rate R1 and the magnetisation transfer saturation -- that can be compared across sites and scanners and carry important information about the underlying microstructure.
1 code implementation • 6 May 2020 • Mikael Brudfors, Yaël Balbastre, John Ashburner
In medical imaging it is common practice to acquire a wide range of modalities (MRI, CT, PET, etc.
2 code implementations • 3 Sep 2019 • Mikael Brudfors, Yael Balbastre, Parashkev Nachev, John Ashburner
The model-driven nature of the approach means that no type of training is needed for applicability to the diversity of MR contrasts present in a clinical context.
no code implementations • 16 Aug 2019 • Mikael Brudfors, John Ashburner, Parashkev Nachev, Yael Balbastre
Automatically generating one medical imaging modality from another is known as medical image translation, and has numerous interesting applications.
1 code implementation • 26 Jul 2019 • Guilherme Pombo, Robert Gray, Tom Varsavsky, John Ashburner, Parashkev Nachev
Second, we show that reformulating this model to approximate a deep Gaussian process yields a measure of uncertainty that improves the performance of semi-supervised learning, in particular classification performance in settings where the proportion of labelled data is low.
1 code implementation • 27 Feb 2019 • Mikael Brudfors, Yaël Balbastre, John Ashburner
Although convolutional neural networks (CNNs) currently dominate competitions on image segmentation, for neuroimaging analysis tasks, more classical generative approaches based on mixture models are still used in practice to parcellate brains.
4 code implementations • 8 Oct 2018 • Mikael Brudfors, Yael Balbastre, Parashkev Nachev, John Ashburner
This paper presents a generative model for super-resolution in routine clinical magnetic resonance images (MRI), of arbitrary orientation and contrast.
no code implementations • 27 Jul 2018 • John Ashburner, Mikael Brudfors, Kevin Bronik, Yael Balbastre
This paper presents a framework for automatically learning shape and appearance models for medical (and certain other) images.
no code implementations • 18 Jul 2018 • Mikael Agn, Per Munck af Rosenschöld, Oula Puonti, Michael J. Lundemann, Laura Mancini, Anastasia Papadaki, Steffi Thust, John Ashburner, Ian Law, Koen van Leemput
In this paper we present a method for simultaneously segmenting brain tumors and an extensive set of organs-at-risk for radiation therapy planning of glioblastomas.
no code implementations • 19 Jun 2018 • Yaël Balbastre, Mikael Brudfors, Kevin Bronik, John Ashburner
Shape modelling describes methods aimed at capturing the natural variability of shapes and commonly relies on probabilistic interpretations of dimensionality reduction techniques such as principal component analysis.
no code implementations • NeuroImage 2018 • Claudia Blaiotta, Patrick Freund, M. Jorge Cardoso, John Ashburner
In this paper we present a hierarchical generative model of medical image data, which can capture simultaneously the variability of both signal intensity and anatomical shapes across large populations.
no code implementations • 5 Jul 2017 • Claudia Blaiotta, Patrick Freund, M. Jorge Cardoso, John Ashburner
In this paper we will focus on the potential and on the challenges associated with the development of an integrated brain and spinal cord modelling framework for processing MR neuroimaging data.