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https://www.readbyqxmd.com/read/28631203/assessment-of-mri-contrast-agent-concentration-by-quantitative-susceptibility-mapping-qsm-application-to-estimation-of-cerebral-blood-volume-during-steady-state
#1
Emelie Lind, Linda Knutsson, Robin Kämpe, Freddy Ståhlberg, Ronnie Wirestam
OBJECTIVE: One major issue in dynamic susceptibility contrast MRI (DSC-MRI) is to accurately determine contrast agent (CA) concentration, since T2* relaxivity in vivo is generally unknown and varies between blood and tissue. In this study, quantitative susceptibility mapping (QSM) was used for quantification of CA concentration. MATERIALS AND METHODS: A DSC-MRI protocol, including phase data acquisition, was applied to 20 healthy volunteers in a test-retest study...
June 19, 2017: Magma
https://www.readbyqxmd.com/read/28602813/automated-segmentation-of-midbrain-structures-with-high-iron-content
#2
REVIEW
Benjamín Garzón, Rouslan Sitnikov, Lars Bäckman, Grégoria Kalpouzos
The substantia nigra (SN), the subthalamic nucleus (STN), and the red nucleus (RN) are midbrain structures of ample interest in many neuroimaging studies, which may benefit from the availability of automated segmentation methods. The high iron content of these structures awards them high contrast in quantitative susceptibility mapping (QSM) images. We present a novel segmentation method that leverages the information of these images to produce automated segmentations of the SN, STN, and RN. The algorithm builds a map of spatial priors for the structures by non-linearly registering a set of manually-traced training labels to the midbrain...
June 9, 2017: NeuroImage
https://www.readbyqxmd.com/read/28601374/quantitative-susceptibility-mapping-qsm-and-r2-in-the-human-brain-at-3t-evaluation-of-intra-scanner-repeatability
#3
Xiang Feng, Andreas Deistung, Jürgen R Reichenbach
Quantitative susceptibility mapping (QSM) and the effective transverse relaxation rate (R2*) can be used to monitor iron and myelin content in brain tissue, which are both subject to changes in many neurological diseases but also during healthy aging. In this study, we quantitatively assessed the repeatability of QSM and R2* by applying four independent scans in eight young healthy, female subjects on a 3T MRI scanner. Since QSM does not yield absolute values for bulk magnetic susceptibilities, we additionally investigated the influence of the choice of a reference brain region for susceptibility by computing susceptibility differences with respect to five different brain structures (whole brain, frontal white matter (fWM), internal capsule (IC), cerebrospinal fluid (CSF) in the lateral ventricle, cortical gray matter (cGM))...
June 7, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28595120/background-field-removal-using-a-region-adaptive-kernel-for-quantitative-susceptibility-mapping-of-human-brain
#4
Jinsheng Fang, Lijun Bao, Xu Li, Peter C M van Zijl, Zhong Chen
Background field removal is an important MR phase preprocessing step for quantitative susceptibility mapping (QSM). It separates the local field induced by tissue magnetic susceptibility sources from the background field generated by sources outside a region of interest, e.g. brain, such as air-tissue interface. In the vicinity of air-tissue boundary, e.g. skull and paranasal sinuses, where large susceptibility variations exist, present background field removal methods are usually insufficient and these regions often need to be excluded by brain mask erosion at the expense of losing information of local field and thus susceptibility measures in these regions...
May 10, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28580758/nuclei-specific-deposits-of-iron-and-calcium-in-the-rat-thalamus-after-status-epilepticus-revealed-with-quantitative-susceptibility-mapping-qsm
#5
Manisha Aggarwal, Xu Li, Olli Gröhn, Alejandra Sierra
PURPOSE: To investigate pathological changes in the rat brain after pilocarpine-induced status epilepticus using quantitative susceptibility mapping (QSM). MATERIALS AND METHODS: 3D multiecho gradient-echo (GRE) data were acquired from ex vivo brains of pilocarpine-injected and age-matched control rats at 11.7T. Maps of R2* and quantitative susceptibility were calculated from the acquired 3D GRE magnitude and phase data, respectively. QSM and R2* maps were compared with Perls' (iron) and Alizarin-red-S (calcium) stainings in the same brains to investigate the pathophysiological basis of susceptibility contrast...
June 5, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28571703/diagnosis-of-intracranial-calcification-and-hemorrhage-in-pediatric-patients-comparison-of-quantitative-susceptibility-mapping-and-phase-images-of-susceptibility-weighted-imaging
#6
S Ciraci, K Gumus, S Doganay, M S Dundar, G D Kaya Ozcora, S B Gorkem, H Per, A Coskun
PURPOSE: To prospectively compare the diagnostic capabilities of quantitative susceptibility mapping (QSM) with those of phase images of susceptibility-weighted imaging (SWI) in the detection and differentiation of intracranial calcification and hemorrhage in pediatric patients. METHOD: Sixteen pediatric patients (9 girls, 7 boys) with a mean age of 9.4±6.3 (SD) years (range, 6 days-15 years) were included. Fifty-nine calcifications and 31 hemorrhages were detected...
May 29, 2017: Diagnostic and Interventional Imaging
https://www.readbyqxmd.com/read/28556247/enhanced-quantitative-susceptibility-mapping-qsm-using-real-time-field-control
#7
Pinar Senay Özbay, Yolanda Duerst, Bertram Jakob Wilm, Klaas Paul Pruessmann, Daniel Nanz
PURPOSE: To assess the potential of a real-time field-control (FC) system for mitigating effects of spatiotemporal field fluctuations in quantitative susceptibility mapping (QSM) at 7 T. METHODS: Magnitude, phase, and QSM images of phantoms and healthy volunteers were acquired under standard conditions and under induced field perturbation (FP) (phantoms: periodic water-bottle displacement; volunteers: deep breathing and forearm movement) with and without FC, which continuously detects and minimizes magnetic-field variations...
May 28, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28556244/coherence-enhancement-in-quantitative-susceptibility-mapping-by-means-of-anisotropic-weighting-in-morphology-enabled-dipole-inversion
#8
Youngwook Kee, Junghun Cho, Kofi Deh, Zhe Liu, Pascal Spincemaille, Yi Wang
PURPOSE: To investigate an anisotropic structural prior in morphology enabled dipole inversion (MEDI) for improving accuracy in quantitative susceptibility mapping (QSM). THEORY AND METHODS: Anisotropic weighting (AW) was devised and implemented to incorporate orientation information into the edge agreement in the MEDI method. AW performance was compared with isotropic weighting by testing and validating on in vivo brain multiple orientation MRI data using COSMOS and the (33) component of the susceptibility tensor as reference...
May 28, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28531270/utilization-of-quantitative-susceptibility-mapping-for-direct-targeting-of-the-subthalamic-nucleus-during-deep-brain-stimulation-surgery
#9
Jonathan Rasouli, Ritesh Ramdhani, Fedor E Panov, Alexey Dimov, Yan Zhang, Catherine Cho, Yi Wang, Brian Harris Kopell
BACKGROUND: Deep brain stimulation of the subthalamic nucleus (STN) has demonstrated efficacy in improving motor disability in Parkinson's disease. The recently developed quantitative susceptibility mapping (QSM) technique, which can accurately map iron deposits in deep brain nuclei, promises precise targeting of the STN. OBJECTIVE: To demonstrate the use of QSM to target STN effectively by correlating with classical physiological-based targeting measures in a prospective study...
May 21, 2017: Operative Neurosurgery (Hagerstown, Md.)
https://www.readbyqxmd.com/read/28526432/quantitative-susceptibility-mapping-using-principles-of-echo-shifting-with-a-train-of-observations-sequence-on-1-5t-mri
#10
Hirohito Kan, Nobuyuki Arai, Harumasa Kasai, Hiroshi Kunitomo, Yasujiro Hirose, Yuta Shibamoto
PURPOSE: To evaluate the accuracy of susceptibility estimated from the principles of echo shifting with a train of observations (PRESTO) sequence using a 1.5T MRI system, we conducted experiments on the human brain using the PRESTO sequence and compared our results with the susceptibility obtained from spoiled gradient-recalled echo (GRE) sequence with flow compensation using quantitative susceptibility mapping (QSM) reconstruction. MATERIALS AND METHODS: Experiments on the human brain were conducted on 12 healthy volunteers (27±4years) using PRESTO and spoiled GRE sequences on a 1...
May 16, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28515413/magnetic-susceptibility-changes-in-the-basal-ganglia-and-brain-stem-of-patients-with-wilson-s-disease-evaluation-with-quantitative-susceptibility-mapping
#11
Selim Doganay, Kazim Gumus, Gonca Koc, Ayse Kacar Bayram, Mehmet Sait Dogan, Duran Arslan, Hakan Gumus, Sureyya Burcu Gorkem, Saliha Ciraci, Halil Ibrahim Serin, Abdulhakim Coskun
OBJECTIVES: Wilson's disease (WD) is characterized with the accumulation of copper in the liver and brain. The objective of this study is to quantitatively measure the susceptibility changes of basal ganglia and brain stem of pediatric patients with neurological WD using quantitative susceptibility mapping (QSM) in comparison to healthy controls. METHODS: Eleven patients with neurological WD (mean age 15 ± 3.3 years, range 10-22 years) and 14 age-matched controls were prospectively recruited...
May 18, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28477179/contribution-of-qsm-imaging-to-the-diagnosis-of-the-rare-syndrome-of-leukoencephalopathy-with-cysts-and-calcification-lcc
#12
Peter Raab, Martin Stangel, Heinrich Lanfermann
We describe the typical computed tomography (CT) and magnetic resonance imaging (MRI) characteristics in a rare case of adult leukoencephalopathy with calcifications and cysts (LCC). In addition, we describe the specific findings of quantified susceptibility mapping (QSM) in this case, relate it to known histopathological findings, and point out possible advantages of this method.
May 5, 2017: Clinical Neuroradiology
https://www.readbyqxmd.com/read/28470768/susceptibility-sensitive-mri-of-multiple-sclerosis-lesions-and-the-impact-of-normal-appearing-white-matter-changes
#13
Vanessa Wiggermann, Simon Hametner, Enedino Hernández-Torres, Christian Kames, Verena Endmayr, Gregor Kasprian, Romana Höftberger, David K B Li, Anthony Traboulsee, Alexander Rauscher
Susceptibility-sensitive magnetic resonance imaging (MRI) has gained importance in multiple sclerosis (MS) research because of its versatility, high resolution and excellent sensitivity to changes in tissue structure and composition. In particular, mapping of the resonance frequency of the MR signal and quantitative susceptibility mapping (QSM) have been explored for the description of MS lesions. Many current studies utilizing these techniques attribute increases in the MR frequency or QSM to elevated tissue iron content, in addition to myelin loss...
May 4, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28465264/quantitative-susceptibility-mapping-as-a-possible-tool-to-radiographically-diagnose-sentinel-headache-associated-with-intracranial-aneurysm-case-report
#14
Daichi Nakagawa, Cameron Cushing, Yasunori Nagahama, Lauren Allan, David Hasan
BACKGROUND: Sentinel headache (SH) occurs before aneurysm rupture in an estimated 15%-60% of cases of aneurysmal subarachnoid hemorrhage (aSAH). By definition, noncontrast computed tomography (CT) scan of the brain and lumbar puncture are both negative in patients presenting with SH. One of the theories explaining this phenomenon is that microhemorrhage (MH) from the aneurysm wall contribute to iron deposition in the interface between the aneurysm wall and brain parenchyma. Quantitative susceptibility mapping (QSM) is a recently introduced magnetic resonance imaging (MRI) technique that has proven capable of localizing the deposition of paramagnetic metals, particularly ferric iron...
April 30, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28438711/can-transverse-relaxation-rates-in-deep-gray-matter-be-approximated-from-functional-and-t2-weighted-flair-scans-for-relative-brain-iron-quantification
#15
Benjamín Garzón, Rouslan Sitnikov, Lars Bäckman, Grégoria Kalpouzos
Alterations in iron concentration in certain deep gray matter regions are known to occur in aging and several clinical conditions. In vivo measurements of R2(∗) transverse relaxation rates and quantitative susceptibility mapping (QSM) have been shown to be strongly correlated with iron concentration in tissue, but their calculation requires the acquisition of a multi-echo gradient recalled echo sequence (MGRE). In the current study, we examined the feasibility of approximating R2(∗) rates using metrics derived from fMRI-EPI and T2-weighted FLAIR images, which are widely available...
July 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28435102/simultaneous-time-interleaved-multislice-stims-for-rapid-susceptibility-weighted-acquisition
#16
Berkin Bilgic, Huihui Ye, Lawrence L Wald, Kawin Setsompop
T2⁎ weighted 3D Gradient Echo (GRE) acquisition is the main sequence used for Susceptibility Weighted Imaging (SWI) and Quantitative Susceptibility Mapping (QSM). These applications require a long echo time (TE) to build up phase contrast, requiring a long repetition time (TR), and leading to excessively lengthy scans. The long TE acquisition creates a significant amount of unused time within each TR, which can be utilized for either multi-echo sampling or additional image encoding with the echo-shift technique...
April 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28424610/characterizing-brain-iron-deposition-in-patients-with-subcortical-vascular-mild-cognitive-impairment-using-quantitative-susceptibility-mapping-a-potential-biomarker
#17
Yawen Sun, Xin Ge, Xu Han, Wenwei Cao, Yao Wang, Weina Ding, Mengqiu Cao, Yong Zhang, Qun Xu, Yan Zhou, Jianrong Xu
The presence and pattern of iron accumulation in subcortical vascular mild cognitive impairment (svMCI) and their effects on cognition have rarely been investigated. We aimed to examine brain iron deposition in svMCI subjects using quantitative susceptibility mapping (QSM). Moreover, we aimed to investigate the correlation between brain iron deposition and the severity of cognitive impairment as indicated by z-scores. We recruited 20 subcortical ischemic vascular disease (SIVD) patients who fulfilled the criteria for svMCI...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28423027/comparison-of-t2-weighted-and-qsm-contrasts-in-parkinson-s-disease-to-visualize-the-stn-with-mri
#18
Anneke Alkemade, Gilles de Hollander, Max C Keuken, Andreas Schäfer, Derek V M Ott, Johannes Schwarz, David Weise, Sonja A Kotz, Birte U Forstmann
The subthalamic nucleus (STN) plays a crucial role in the surgical treatment of Parkinson's disease (PD). Studies investigating optimal protocols for STN visualization using state of the art magnetic resonance imaging (MRI) techniques have shown that susceptibility weighted images, which display the magnetic susceptibility distribution, yield better results than T1-weighted, T2-weighted, and T2*-weighted contrasts. However, these findings are based on young healthy individuals, and require validation in elderly individuals and persons suffering from PD...
2017: PloS One
https://www.readbyqxmd.com/read/28392492/pulse-sequences-and-parallel-imaging-for-high-spatiotemporal-resolution-mri-at-ultra-high-field
#19
Benedikt A Poser, Kawin Setsompop
The SNR and CNR benefits of ultra-high field (UHF) have helped push the envelope of achievable spatial resolution in MRI. For applications based on susceptibility contrast where there is a large CNR gain, high quality sub-millimeter resolution imaging is now being routinely performed, particularly in fMRI and phase imaging/QSM. This has enabled the study of structure and function of very fine-scale structures in the brain. UHF has also helped push the spatial resolution of many other MRI applications as will be outlined in this review...
April 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28391484/genomic-and-molecular-characterization-of-a-novel-quorum-sensing-molecule-in-bacillus-licheniformis
#20
Elham Esmaeilishirazifard, Daniela De Vizio, Sterghios A Moschos, Tajalli Keshavarz
Quorum sensing molecules (QSMs) are involved in the regulation of complicated processes helping bacterial populations respond to changes in their cell-density. Although the QS gene cluster (comQXPA) has been identified in the genome sequence of some bacilli, the QS system B. licheniformis has not been investigated in detail, and its QSM (ComX pheromone) has not been identified. Given the importance of this antagonistic bacterium as an industrial workhorse, this study was aimed to elucidate B. licheniformis NCIMB-8874 QS...
December 2017: AMB Express
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