Three dimensional modelling of the human tongue musculature : definition of a method based on active contours

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Robust preprocessing for stimulus-based functional MRI of the moving fetus

© 2016 The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its. Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta

Robust preprocessing for stimulus-based functional MRI of the moving fetus.

Fetal motion manifests as signal degradation and image artifact in the acquired time series of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) studies. We present a robust preprocessing pipeline to specifically address fetal and placental motion-induced artifacts in stimulus-based fMRI with slowly cycled block design in the living fetus. In the proposed pipeline, motion correction is optimized to the experimental paradigm, and it is performed separately in each phase as well as in each region of interest (ROI), recognizing that each phase and organ experiences different types of motion. To obtain the averaged BOLD signals for each ROI, both misaligned volumes and noisy voxels are automatically detected and excluded, and the missing data are then imputed by statistical estimation based on local polynomial smoothing. Our experimental results demonstrate that the proposed pipeline was effective in mitigating the motion-induced artifacts in stimulus-based fMRI data of the fetal brain and placenta

Robust motion correction and outlier rejection of in vivo functional MR images of the fetal brain and placenta during maternal hyperoxia

Subject motion is a major challenge in functional magnetic resonance imaging studies (fMRI) of the fetal brain and placenta during maternal hyperoxia. We propose a motion correction and volume outlier rejection method for the correction of severe motion artifacts in both fetal brain and placenta. The method is optimized to the experimental design by processing different phases of acquisition separately. It also automatically excludes high-motion volumes and all the missing data are regressed from ROI-averaged signals. The results demonstrate that the proposed method is effective in enhancing motion correction in fetal fMRI without large data loss, compared to traditional motion correction methods

Frequency of Hospitalizations for Pain and Association With Altered Brain Network Connectivity in Sickle Cell Disease.

Sickle cell disease (SCD) is a hemoglobinopathy affecting more than 100,000 individuals in United States. The disease is characterized by presence of sickle hemoglobin and recurrent episodes of pain. Some individuals with SCD experience frequent hospitalizations and high burden of pain. The role of central mechanisms in SCD pain has not been explored. Twenty-five adolescents and young adults with SCD underwent functional MRI (fMRI). Participants were stratified into high or low pain groups based on the number of hospitalizations for pain in preceding 12 months. Resting state functional connectivity was analyzed using seed based and dual-regression independent component analysis. Intrinsic brain connectivity was compared between high and low pain groups and association with fetal hemoglobin, a known modifier of SCD, was explored. Patients in the high pain group displayed an excess of pro-nociceptive connectivity such as anterior cingulate to default-mode-network structures such as the precuneus, whereas patients in low pain group showed more connectivity to anti-nociceptive structures such as the peri- and sub-genual cingulate. Although a similar proportion of patients in both groups reported to be on hydroxyurea, the fetal hemoglobin levels were significantly higher in the low pain group and were associated with greater connectivity to anti-nociceptive structures. These findings support the role of central mechanisms in SCD pain. Intrinsic brain connectivity should be explored as a complementary and objective outcome measure in SCD pain research