DD-INR: Dynamics-Driven Implicit Neural Representation for Accelerated Whole-Brain Functional MRI Reconstruction
2026-06-09 Qiaoxin Li, Caini Pan, Pierre-Antoine Comby, et al. Lecture Notes in Computer Science

Accelerated acquisition of fMRI enables enhanced detection of neurovascular (BOLD) activity in the brain, but image reconstruction becomes challenging with high k-space undersampling: Task-evoked BOLD signals are small in magnitude, which traditional anatomical MRI reconstruction methods fail to recover, as they favor…

Combining Cartesian and non-Cartesian acceleration techniques with SPARKLING for 1mm isotropic whole-brain MPRAGE in a minute
2026-05-29 Chaithya Giliyar Radhakrishna, Aurélien Massire, Blanche Bapst, et al. arXiv preprint arXiv:2605.31017

Purpose: T1-weighted MPRAGE remains a cornerstone of clinical anatomical imaging, yet its long acquisition times constrain routine use. Established acceleration techniques, namely Parallel Imaging (PI) and Compressed Sensing (CS), tend to introduce substantial noise and blurring when pushed to high acceleration…

Benchmarking 3D multi-coil NC-PDNet MRI reconstruction
2025-09-16 Asma Tanabene, Chaithya Giliyar Radhakrishna, Aurélien Massire, et al. 2025 IEEE 22nd International Symposium on Biomedical Imaging (ISBI)

Motivation: Deep Neural Networks (DNNs) show promise in reconstructing undersampled MRI data but face challenges with non-Cartesian 3D multi-coil acquisitions due to high memory demands and training complexity. Goal(s): To address the research gap in validating DNNs performances for non-Cartesian data in 3D multi-coil…

Non-cartesian 3D-SPARKLING vs cartesian 3D-EPI encoding schemes for functional magnetic resonance Imaging at 7 Tesla
2024-05-13 Zaineb Amor, Philippe Ciuciu, Chaithya Giliyar Radhakrishna, et al. Plos one

The quest for higher spatial and/or temporal resolution in functional MRI (fMRI) while preserving a sufficient temporal signal-to-noise ratio (tSNR) has generated a tremendous amount of methodological contributions in the last decade ranging from Cartesian vs. non-Cartesian readouts, 2D vs.

B0 field distortions monitoring and correction for 3D non-Cartesian fMRI acquisitions using a field camera: Application to 3D-SPARKLING at 7T
2023-08-03 Zaineb Amor, Chaithya Giliyar Radhakrishna, Caroline Le Ster, et al. Joint Annual Meeting ISMRM-ESMRMB & ISMRT 31st Annual Meeting

The benefit of retrospective correction of static and dynamic B0 field imperfections was studied on non-Cartesian compressed sensing-based acquisition patterns by taking as an example 3D-SPARKLING encoding scheme. Long-TR dynamic acquisitions of T2*-weighted MRI (fMRI-like) volumes were acquired at 7T, retrospectively…

Designing and learning non-Cartesian k-space sampling trajectories for accelerated 3D MRI
2023-04-25 Chaithya Giliyar Radhakrishna theses.fr (ABES)

Conception et apprentissage de trajectoires d'échantillonnage non cartésiennes dans l'espace k pour l'IRM 3D accélérée L'imagerie par résonance magnétique (IRM) est une technique d'imagerie médicale non invasive très répandue qui permet de comprendre les structures des tissus du corps humain. Cependant, sa portée et…

Jointly learning non-cartesian k-space trajectories and reconstruction networks for 2D and 3D MR imaging through projection
2023-01-24 Chaithya Giliyar Radhakrishna, Philippe Ciuciu Bioengineering

Compressed sensing in magnetic resonance imaging essentially involves the optimization of (1) the sampling pattern in k-space under MR hardware constraints and (2) image reconstruction from undersampled k-space data. Recently, deep learning methods have allowed the community to address both problems simultaneously,…

Hybrid learning of non-cartesian k-space trajectory and MR image reconstruction networks
2021-10-25 Chaithya Giliyar Radhakrishna, Zaccharie Ramzi, Philippe Ciuciu 2022 IEEE 19th International Symposium on Biomedical Imaging (ISBI)

Compressed sensing (CS) in Magnetic resonance Imaging (MRI) essentially involves the optimization of 1) the sampling pattern in k-space under MR hardware constraints and 2) image reconstruction from the undersampled k-space data. Recently, deep learning methods have allowed the community to address both problems…

Learning the sampling density in 2D SPARKLING MRI acquisition for optimized image reconstruction
2021-08-23 Chaithya Giliyar Radhakrishna, Zaccharie Ramzi, Philippe Ciuciu 2021 29th European Signal Processing Conference (EUSIPCO)

The SPARKLING algorithm was originally developed for accelerated 2D magnetic resonance imaging (MRI) in the compressed sensing (CS) context. It yields non-Cartesian sampling trajectories that jointly fulfill a target sampling density while each individual trajectory complies with MR hardware constraints.

Optimizing full 3D SPARKLING trajectories for high-resolution T2*-weighted Magnetic Resonance Imaging
2021-08-06 Chaithya Giliyar Radhakrishna, Pierre Weiss, Guillaume Daval-Frérot, et al. IEEE Transactions on Medical Imaging

The Spreading Projection Algorithm for Rapid K-space samplING, or SPARKLING, is an optimization-driven method that has been recently introduced for accelerated 2D T2*-w MRI using compressed sensing. It has then been extended to address 3D imaging using either stacks of 2D sampling patterns or a local 3D strategy that…

Calibration-less multi-coil compressed sensing magnetic resonance image reconstruction based on OSCAR regularization
2021-03-19 Loubna El Gueddari, Chaithya Giliyar Radhakrishna, Emilie Chouzenoux, Philippe Ciuciu Journal of Imaging

Over the last decade, the combination of compressed sensing (CS) with acquisition over multiple receiver coils in magnetic resonance imaging (MRI) has allowed the emergence of faster scans while maintaining a good signal-to-noise ratio (SNR). Self-calibrating techniques, such as ESPiRIT, have become the standard…

PySAP: Python Sparse Data Analysis Package for multidisciplinary image processing
2020-06-25 S. Farrens, Antoine Grigis, Loubna El Gueddari, et al. Astronomy and Computing

We present the open-source image processing software package PySAP (Python Sparse data Analysis Package) developed for the COmpressed Sensing for Magnetic resonance Imaging and Cosmology (COSMIC) project. This package provides a set of flexible tools that can be applied to a variety of compressed sensing and image…