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https://www.readbyqxmd.com/read/29138089/rapid-two-step-dipole-inversion-for-susceptibility-mapping-with-sparsity-priors
#1
Christian Kames, Vanessa Wiggermann, Alexander Rauscher
Quantitative susceptibility mapping (QSM) is a post-processing technique of gradient echo phase data that attempts to map the spatial distribution of local tissue magnetic susceptibilities. To obtain these maps, an ill-posed field-to-source inverse problem must be solved to remove non-local magnetic field perturbations. Current state-of-the-art algorithms which aim to solve the dipole inversion problem are plagued by the trade-off between reconstruction speed and accuracy. A two-step dipole inversion algorithm is proposed to bridge this gap...
November 11, 2017: NeuroImage
https://www.readbyqxmd.com/read/29130526/phase-processing-for-quantitative-susceptibility-mapping-of-regions-with-large-susceptibility-and-lack-of-signal
#2
Véronique Fortier, Ives R Levesque
PURPOSE: Phase processing impacts the accuracy of quantitative susceptibility mapping (QSM). Techniques for phase unwrapping and background removal have been proposed and demonstrated mostly in brain. In this work, phase processing was evaluated in the context of large susceptibility variations (Δχ) and negligible signal, in particular for susceptibility estimation using the iterative phase replacement (IPR) algorithm. METHODS: Continuous Laplacian, region-growing, and quality-guided unwrapping were evaluated...
November 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29079523/combining-images-and-anatomical-knowledge-to-improve-automated-vein-segmentation-in-mri
#3
Phillip G D Ward, Nicholas J Ferris, Parnesh Raniga, David L Dowe, Amanda C L Ng, David G Barnes, Gary F Egan
PURPOSE: To improve the accuracy of automated vein segmentation by combining susceptibility-weighted images (SWI), quantitative susceptibility maps (QSM), and a vein atlas to produce a resultant image called a composite vein image (CV image). METHOD: An atlas was constructed in common space from manually traced MRI images from ten volunteers. The composite vein image was derived for each subject as a weighted sum of three inputs; an SWI image, a QSM image and the vein atlas...
October 25, 2017: NeuroImage
https://www.readbyqxmd.com/read/29075619/modulating-the-global-response-regulator-luxo-of-v-cholerae-quorum-sensing-system-using-a-pyrazine-dicarboxylic-acid-derivative-pdca-py-an-antivirulence-approach
#4
M Hema, Sahana Vasudevan, P Balamurugan, S Adline Princy
Vibrio cholerae is a Gram-negative pathogen which causes acute diarrhoeal disease, cholera by the expression of virulence genes through quorum sensing (QS) mechanism. The QS circuit of V. cholerae is controlled by the global quorum regulator, LuxO, which at low cell density (LCD) state produces major virulence factors such as, toxin co-regulated pilus (TCP) and cholera toxin (CT) to mediate infection. On the contrary, at the high cell density (HCD) state the virulent genes are downregulated and the vibrios are detached from the host intestinal epithelial cells, promoted by HapA protease...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29067730/simultaneous-qsm-and-metabolic-imaging-of-the-brain-using-spice
#5
Xi Peng, Fan Lam, Yudu Li, Bryan Clifford, Zhi-Pei Liang
PURPOSE: To map brain metabolites and tissue magnetic susceptibility simultaneously using a single three-dimensional (1) H-MRSI acquisition without water suppression. METHODS: The proposed technique builds on a subspace imaging method called spectroscopic imaging by exploiting spatiospectral correlation (SPICE), which enables ultrashort echo time (TE)/short pulse repetition time (TR) acquisitions for (1) H-MRSI without water suppression. This data acquisition scheme simultaneously captures both the spectral information of brain metabolites and the phase information of the water signals that is directly related to tissue magnetic susceptibility variations...
October 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29056394/strategically-acquired-gradient-echo-stage-imaging-part-i-creating-enhanced-t1-contrast-and-standardized-susceptibility-weighted-imaging-and-quantitative-susceptibility-mapping
#6
Yongsheng Chen, Saifeng Liu, Yu Wang, Yan Kang, E Mark Haacke
PURPOSE: To provide whole brain grey matter (GM) to white matter (WM) contrast enhanced T1W (T1WE) images, multi-echo quantitative susceptibility mapping (QSM), proton density (PD) weighted images, T1 maps, PD maps, susceptibility weighted imaging (SWI), and R2* maps with minimal misregistration in scanning times <5min. METHODS: Strategically acquired gradient echo (STAGE) imaging includes two fully flow compensated double echo gradient echo acquisitions with a resolution of 0...
October 19, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29023982/medi-0-morphology-enabled-dipole-inversion-with-automatic-uniform-cerebrospinal-fluid-zero-reference-for-quantitative-susceptibility-mapping
#7
Zhe Liu, Pascal Spincemaille, Yihao Yao, Yan Zhang, Yi Wang
PURPOSE: To develop a quantitative susceptibility mapping (QSM) method with a consistent zero reference using minimal variation in cerebrospinal fluid (CSF) susceptibility. THEORY AND METHODS: The ventricular CSF was automatically segmented on the R2* map. An L2 -regularization was used to enforce CSF susceptibility homogeneity within the segmented region, with the averaged CSF susceptibility as the zero reference. This regularization for CSF homogeneity was added to the model used in a prior QSM method (morphology enabled dipole inversion [MEDI])...
October 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29018934/quantitative-susceptibility-mapping-of-the-motor-cortex-a-comparison-of-susceptibility-among-patients-with-amyotrophic-lateral-sclerosis-cerebrovascular-disease-and-healthy-controls
#8
Ji Young Lee, Young-Jun Lee, Dong Woo Park, Yoonho Nam, Seung Hyun Kim, Jinseok Park, Young Seo Kim, Hyun Young Kim, Ki-Wook Oh
PURPOSE: The purpose of this study was to investigate the differences in motor cortex susceptibility among patients with amyotrophic lateral sclerosis (ALS), cerebrovascular disease (CVD), and healthy controls using quantitative susceptibility mapping (QSM). METHODS: We retrospectively reviewed 78 QSM images from 26 patients with ALS, 26 age- and sex-matched patients with CVD, and 26 healthy controls. A region of interest was drawn in the hand lobule of both the motor cortexes and subcortical white matter...
December 2017: Neuroradiology
https://www.readbyqxmd.com/read/28902421/the-impact-of-white-matter-fiber-orientation-in-single-acquisition-quantitative-susceptibility-mapping
#9
Marta Lancione, Michela Tosetti, Graziella Donatelli, Mirco Cosottini, Mauro Costagli
The aim of this work was to assess the impact of tissue structural orientation on quantitative susceptibility mapping (QSM) reliability, and to provide a criterion to identify voxels in which measures of magnetic susceptibility (χ) are most affected by spatial orientation effects. Four healthy volunteers underwent 7-T magnetic resonance imaging (MRI). Multi-echo, gradient-echo sequences were used to obtain quantitative maps of frequency shift (FS) and χ. Information from diffusion tensor imaging (DTI) was used to investigate the relationship between tissue orientation and FS measures and QSM...
September 13, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28900391/quantitative-susceptibility-mapping-reveals-an-association-between-brain-iron-load-and-depression-severity
#10
Shun Yao, Yi Zhong, Yuhao Xu, Jiasheng Qin, Ningning Zhang, Xiaolan Zhu, Yuefeng Li
Previous studies have detected abnormal serum ferritin levels in patients with depression; however, the results have been inconsistent. This study used quantitative susceptibility mapping (QSM) for the first time to examine brain iron concentration in depressed patients and evaluated whether it is related to severity. We included three groups of age- and gender-matched participants: 30 patients with mild-moderate depression (MD), 14 patients with major depression disorder (MDD) and 20 control subjects. All participants underwent MR scans with a 3D gradient-echo sequence reconstructing for QSM and performed the 17-item Hamilton Depression Rating Scale (HDRS) test...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28886909/quantitative-susceptibility-mapping-differentiates-between-parkinsonian-disorders
#11
Henrik Sjöström, Tobias Granberg, Eric Westman, Per Svenningsson
INTRODUCTION: It is often challenging to clinically distinguish between Parkinson's disease (PD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Quantitative susceptibility mapping (QSM) is an accurate indirect method for estimating brain iron levels in vivo. This method has yet to be applied in atypical parkinsonism. We aimed to investigate differences in brain iron accumulation parkinsonian disorders and healthy controls using QSM. METHODS: 15 patients with PSP, 11 patients with MSA, 62 patients with PD and 14 healthy controls were included in the study and their phase and magnitude data from susceptibility-weighted magnetic resonance imaging were retrospectively analyzed with an in-house pipeline to create susceptibility maps...
September 1, 2017: Parkinsonism & related Disorders
https://www.readbyqxmd.com/read/28885147/quantitative-susceptibility-mapping-qsm-algorithms-mathematical-rationale-and-computational-implementations
#12
Youngwook Kee, Zhe Liu, Liangdong Zhou, Alexey Dimov, Junghun Cho, Ludovic de Rochefort, Jin Keun Seo, Yi Wang
Quantitative susceptibility mapping (QSM) solves the magnetic field-to-magnetization (tissue susceptibility) inverse problem under conditions of noisy and incomplete field data acquired using magnetic resonance imaging. Therefore, sophisticated algorithms are necessary to treat the ill-posed nature of the problem and are reviewed here. The forward problem is typically presented as an integral form, where the field is the convolution of the dipole kernel and tissue susceptibility distribution. This integral form can be equivalently written as a partial differential equation (PDE)...
2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28879084/quantitative-susceptibility-mapping-to-evaluate-the-early-stage-of-alzheimer-s-disease
#13
Hyug-Gi Kim, Soonchan Park, Hak Young Rhee, Kyung Mi Lee, Chang-Woo Ryu, Sun Jung Rhee, Soo Yeol Lee, Yi Wang, Geon-Ho Jahng
The objective of this study was to evaluate susceptibility changes caused by iron accumulation in cognitive normal (CN) elderly, those with amnestic mild cognitive impairment (aMCI), and those with early state AD, and to compare the findings with gray matter volume (GMV) changes caused by neuronal loss. The participants included 19 elderly CN, 19 aMCI, and 19 AD subjects. The voxel-based quantitative susceptibility map (QSM) and GMV in the brain were calculated and the differences of those insides were compared among the three groups...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28815906/deep-gray-matter-iron-measurement-in-patients-with-liver-cirrhosis-using-quantitative-susceptibility-mapping-relationship-with-pallidal-t1-hyperintensity
#14
Song Lee, Yoonho Nam, Jinhee Jang, Gun Hyung Na, Dong Goo Kim, Na-Young Shin, Hyun Seok Choi, So-Lyung Jung, Kook-Jin Ahn, Bum-Soo Kim
BACKGROUND: The liver is a central organ for the metabolism of iron and manganese and the places where those metals are commonly deposited overlap in the brain. PURPOSE/HYPOTHESIS: To elucidate the relationship between pallidal T1 hyperintensity and iron deposition in the deep gray matter of liver cirrhosis patients using quantitative susceptibility mapping (QSM). STUDY TYPE: Retrospective case-control study SUBJECTS: In all, 38 consecutive liver cirrhosis patients who received brain magnetic resonance imaging (MRI) as pretransplant evaluation...
August 17, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28797738/tissue-magnetic-susceptibility-mapping-as-a-marker-of-tau-pathology-in-alzheimer-s-disease
#15
J O'Callaghan, H Holmes, N Powell, J A Wells, O Ismail, I F Harrison, B Siow, R Johnson, Z Ahmed, A Fisher, S Meftah, M J O'Neill, T K Murray, E C Collins, K Shmueli, M F Lythgoe
Alzheimer's disease is connected to a number of other neurodegenerative conditions, known collectively as 'tauopathies', by the presence of aggregated tau protein in the brain. Neuroinflammation and oxidative stress in AD are associated with tau pathology and both the breakdown of axonal sheaths in white matter tracts and excess iron accumulation grey matter brain regions. Despite the identification of myelin and iron concentration as major sources of contrast in quantitative susceptibility maps of the brain, the sensitivity of this technique to tau pathology has yet to be explored...
August 4, 2017: NeuroImage
https://www.readbyqxmd.com/read/28791783/quantitative-susceptibility-mapping-as-a-monitoring-biomarker-in-cerebral-cavernous-malformations-with-recent-hemorrhage
#16
Hussein A Zeineddine, Romuald Girard, Ying Cao, Nicholas Hobson, Maged D Fam, Agnieszka Stadnik, Huan Tan, Jingjing Shen, Kiranj Chaudagar, Robert Shenkar, Richard E Thompson, Nichol McBee, Daniel Hanley, Timothy Carroll, Gregory A Christoforidis, Issam A Awad
BACKGROUND: Quantitative Susceptibility Mapping (QSM) MRI allows accurate assessment of iron content in cerebral cavernous malformations (CCM), and a threshold increase by 6% in QSM has been shown to reflect new symptomatic hemorrhage (SH) in previously stable lesions. PURPOSE/HYPOTHESIS: It is unclear how lesional QSM evolves in CCMs after recent SH, and whether this could serve as a monitoring biomarker in clinical trials aimed at preventing rebleeding in these lesions...
August 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28762243/quantitative-susceptibility-mapping-report-from-the-2016-reconstruction-challenge
#17
Christian Langkammer, Ferdinand Schweser, Karin Shmueli, Christian Kames, Xu Li, Li Guo, Carlos Milovic, Jinsuh Kim, Hongjiang Wei, Kristian Bredies, Sagar Buch, Yihao Guo, Zhe Liu, Jakob Meineke, Alexander Rauscher, José P Marques, Berkin Bilgic
PURPOSE: The aim of the 2016 quantitative susceptibility mapping (QSM) reconstruction challenge was to test the ability of various QSM algorithms to recover the underlying susceptibility from phase data faithfully. METHODS: Gradient-echo images of a healthy volunteer acquired at 3T in a single orientation with 1.06 mm isotropic resolution. A reference susceptibility map was provided, which was computed using the susceptibility tensor imaging algorithm on data acquired at 12 head orientations...
July 31, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28747100/loading-and-elution-characteristics-of-quadrasphere-microspheres-loaded-with-bevacizumab
#18
Martin Oselkin, Neda I Sedora-Roman, Bryan A Pukenas, David Kung, Robert W Hurst
AIM: Super absorbent polyvinyl alcohol-sodium acrylate copolymer microspheres, Quadrasphere microspheres (QSM), are commonly used for drug-eluting bead therapy, however, the literature only reports its use with small molecule chemotherapeutics. This study evaluates the loading and elution characteristics of bevacizumab-loaded QSM. METHODS & RESULTS: A single vial of QSM was reconstituted with 200 mg of bevacizumab. Drug concentration was determined by ELISA immunoassay...
July 27, 2017: Therapeutic Delivery
https://www.readbyqxmd.com/read/28731570/susceptibility-weighted-imaging-and-quantitative-susceptibility-mapping-of-the-cerebral-vasculature-using-ferumoxytol
#19
Saifeng Liu, Jean-Christophe Brisset, Jiani Hu, E Mark Haacke, Yulin Ge
PURPOSE: To demonstrate the potential of imaging cerebral arteries and veins with ferumoxytol using susceptibility weighted imaging (SWI) and quantitative susceptibility mapping (QSM). MATERIALS AND METHODS: The relationships between ferumoxytol concentration and the apparent susceptibility at 1.5T, 3T, and 7T were determined using phantom data; the ability of visualizing subvoxel vessels was evaluated using simulations; and the feasibility of using ferumoxytol to enhance the visibility of small vessels was confirmed in three healthy volunteers at 7T(with doses 1 mg/kg to 4 mg/kg)...
July 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28689259/differential-diagnosis-of-parkinsonism-by-a-combined-use-of-diffusion-kurtosis-imaging-and-quantitative-susceptibility-mapping
#20
Kenji Ito, Chigumi Ohtsuka, Kunihiro Yoshioka, Hiroyuki Kameda, Suguru Yokosawa, Ryota Sato, Yasuo Terayama, Makoto Sasaki
PURPOSE: We investigated whether diffusion kurtosis imaging (DKI) and quantitative susceptibility mapping (QSM) could detect pathological changes that occur in Parkinson's disease (PD), multiple system atrophy with predominant parkinsonism (MSA-P) or predominant cerebellar ataxia (MSA-C), and progressive supranuclear palsy syndrome (PSPS) and thus be used for differential diagnosis that is often difficult. METHODS: Seventy patients (41 with PD, 6 with MSA-P, 7 with MSA-C, 16 with PSPS) and 20 healthy controls were examined using a 3...
August 2017: Neuroradiology
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