Adaptive scan strategies for fetal MRI imaging using slice to volume techniques

© 2015 IEEE.In this paper several novel methods to account for fetal movements during fetal Magnetic Resonance Imaging (fetal MRI) are explored. We show how slice-to-volume reconstruction methods can be used to account for motion adaptively during the scan. Three candidate methods are tested for their feasibility and integrated into a computer simulation of fetal MRI. The first alters the main orientation of the stacks used for reconstruction, the second stops if too much motion occurs during slice acquisition and the third steers the orientation of each slice individually. Reconstruction informed adaptive scanning can provide a peak signal-to-noise ratio (PSNR) improvement of up to 2 dB after only two stacks of scanned slices and is more efficient with respect to the uncertainty of the final reconstruction

Efficient multi-class fetal brain segmentation in high resolution MRI reconstructions with noisy labels

Segmentation of the developing fetal brain is an important step in quantitative analyses. However, manual segmentation is a very time-consuming task which is prone to error and must be completed by highly specialized indi-viduals. Super-resolution reconstruction of fetal MRI has become standard for processing such data as it improves image quality and resolution. However, dif-ferent pipelines result in slightly different outputs, further complicating the gen-eralization of segmentation methods aiming to segment super-resolution data. Therefore, we propose using transfer learning with noisy multi-class labels to automatically segment high resolution fetal brain MRIs using a single set of seg-mentations created with one reconstruction method and tested for generalizability across other reconstruction methods. Our results show that the network can auto-matically segment fetal brain reconstructions into 7 different tissue types, regard-less of reconstruction method used. Transfer learning offers some advantages when compared to training without pre-initialized weights, but the network trained on clean labels had more accurate segmentations overall. No additional manual segmentations were required. Therefore, the proposed network has the potential to eliminate the need for manual segmentations needed in quantitative analyses of the fetal brain independent of reconstruction method used, offering an unbiased way to quantify normal and pathological neurodevelopment.Comment: Accepted for publication at PIPPI MICCAI 202

Les séquences diagénétiques des calcarénites littorales du Pleistocène récent de Crète septentrionale : une aide à la résolution des problèmes de corrélation

Actes du colloque PICG 367/INQUA/SGF, Perpignan 2-4 décembre 199

Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia, Crète / Stepped corrosion benches of Tyrrhenian age (stade 5.1) in Malia, Crete

Abstract Morphologic and stratigraphie remnants of the two latest transgressions ofisotopic stage 5 (5.3 et 5.1) are preserved on the cliff of Malia. They allow the dating of a contrasted tectonic activity during isotop stage 5.1 : first, stepped corrosion benches were provoked by a swift jerky surrection; later, the shaping of a lower incline plane covered with Vermetids was made during a more gentle and progressive surrection.Résumé La falaise de Malia a conservé des témoins morphologiques et stratigraphiques des deux dernières transgressions du stade isotopique 5 (5.3 et 5.1). Ces témoins permettent de dater une activité tectonique contrastée pendant le stade 5.1 : des trottoirs de corrosion étages s'expliquent par une surrection saccadée, le plan incliné inférieur tapissé de vermétidés s'expliquant, lui, par une surrection ultérieure plus douce et plus progressive.Dalongeville Rémi, Kéraudren Bertrand, Bernier Paul, Renault-Miskovsky Josette. Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia, Crète / Stepped corrosion benches of Tyrrhenian age (stade 5.1) in Malia, Crete. In: Géomorphologie : relief, processus, environnement, Janvier-mars, vol. 6, n°1. pp. 21-24

Trottoirs de corrosion étagés d'âge tyrrhénien (stade 5.1) à Malia

International audienceLa falaise de Malia a conservé des témoins morphologiques et stratigraphiques des deux dernières transgressions du stade isotopique 5 (5.3 et 5.1). Ces témoins permettent de dater une activité tectonique contrastée pendant le stade 5.1 : des trottoirs de corrosion étages s'expliquent par une surrection saccadée, le plan incliné inférieur tapissé de vermétidés s'expliquant, lui, par une surrection ultérieure plus douce et plus progressiv

Indices morphologiques de microvariations de la ligne de rivage pendant la transgression du stade 5.1 (Pléistocène supérieur) : le site des Charniers à Malia (Crète septentrionale). Résumés

Colloque de Paris, 5-6 novembre 199

Fast motion compensation and super-resolution from multiple stacks of 2D slices

This tool implements a novel method for the correction of motion artifacts as acquired in fetal Magnetic Resonance Imaging (MRI) scans of the whole uterus. Contrary to current slice-to-volume registration (SVR) methods, requiring an inflexible enclosure of a single investigated organ, the proposed patch-to-volume reconstruction (PVR) approach is able to reconstruct a large field of view of non-rigidly deforming structures. It relaxes rigid motion assumptions by introducing a defined amount of redundant information that is addressed with parallelized patch-wise optimization and automatic outlier rejection. We further describe and provide an efficient parallel implementation of PVR allowing its execution within reasonable time on commercially available graphics processing units (GPU), enabling its use in the clinical practice. We evaluate PVR’s computational overhead compared to standard methods and observe improved reconstruction accuracy in presence of affine motion artifacts of approximately 30% compared to conventional SVR in synthetic experiments. Furthermore, we have verified our method qualitatively and quantitatively on real fetal MRI data subject to maternal breathing and sudden fetal movements. We evaluate peak-signal-to-noise ratio (PSNR), structural similarity index (SSIM), and cross correlation (CC) with respect to the originally acquired data and provide a method for visual inspection of reconstruction uncertainty. With these experiments we demonstrate successful application of PVR motion compensation to the whole uterus, the human fetus, and the human placenta.This tool implements a novel method for the correction of motion artifacts as acquired in fetal Magnetic Resonance Imaging (MRI) scans of the whole uterus. Contrary to current slice-to-volume registration (SVR) methods, requiring an inflexible enclosure of a single investigated organ, the proposed patch-to-volume reconstruction (PVR) approach is able to reconstruct a large field of view of non-rigidly deforming structures. It relaxes rigid motion assumptions by introducing a defined amount of redundant information that is addressed with parallelized patch-wise optimization and automatic outlier rejection. We further describe and provide an efficient parallel implementation of PVR allowing its execution within reasonable time on commercially available graphics processing units (GPU), enabling its use in the clinical practice. We evaluate PVR’s computational overhead compared to standard methods and observe improved reconstruction accuracy in presence of affine motion artifacts of approximately 30% compared to conventional SVR in synthetic experiments. Furthermore, we have verified our method qualitatively and quantitatively on real fetal MRI data subject to maternal breathing and sudden fetal movements. We evaluate peak-signal-to-noise ratio (PSNR), structural similarity index (SSIM), and cross correlation (CC) with respect to the originally acquired data and provide a method for visual inspection of reconstruction uncertainty. With these experiments we demonstrate successful application of PVR motion compensation to the whole uterus, the human fetus, and the human placenta.1.

Le Pléistoscène supérieur marin (Tyrrhénien) en Crète nord-orientale (Grèce)

International audienc