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https://www.readbyqxmd.com/read/28926131/region-specific-impairment-of-the-cervical-spinal-cord-sc-in-amyotrophic-lateral-sclerosis-a-preliminary-study-using-sc-templates-and-quantitative-mri-diffusion-tensor-imaging-inhomogeneous-magnetization-transfer
#1
Henitsoa Rasoanandrianina, Aude-Marie Grapperon, Manuel Taso, Olivier M Girard, Guillaume Duhamel, Maxime Guye, Jean-Philippe Ranjeva, Shahram Attarian, Annie Verschueren, Virginie Callot
In this preliminary study, our objective was to investigate the potential of high-resolution anatomical imaging, diffusion tensor imaging (DTI) and conventional/inhomogeneous magnetization transfer imaging [magnetization transfer (MT)/inhomogeneous magnetization transfer (ihMT)] at 3 T, analyzed with template-extracted regions of interest, to measure the atrophy and structural changes of white (WM) and gray (GM) matter spinal cord (SC) occurring in patients with amyotrophic lateral sclerosis (ALS). Ten patients with ALS and 20 age-matched healthy controls were recruited...
September 19, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28921614/an-optimized-framework-for-quantitative-magnetization-transfer-imaging-of-the-cervical-spinal-cord-in-vivo
#2
Marco Battiston, Francesco Grussu, Andrada Ianus, Torben Schneider, Ferran Prados, James Fairney, Sebastien Ourselin, Daniel C Alexander, Mara Cercignani, Claudia A M Gandini Wheeler-Kingshott, Rebecca S Samson
PURPOSE: To develop a framework to fully characterize quantitative magnetization transfer indices in the human cervical cord in vivo within a clinically feasible time. METHODS: A dedicated spinal cord imaging protocol for quantitative magnetization transfer was developed using a reduced field-of-view approach with echo planar imaging (EPI) readout. Sequence parameters were optimized based in the Cramer-Rao-lower bound. Quantitative model parameters (i.e., bound pool fraction, free and bound pool transverse relaxation times [ T2F, T2B], and forward exchange rate [kFB ]) were estimated implementing a numerical model capable of dealing with the novelties of the sequence adopted...
September 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28917698/introducing-axonal-myelination-in-connectomics-a-preliminary-analysis-of-g-ratio-distribution-in-healthy-subjects
#3
REVIEW
Matteo Mancini, Giovanni Giulietti, Nicholas Dowell, Barbara Spanò, Neil Harrison, Marco Bozzali, Mara Cercignani
Microstructural imaging and connectomics are two research areas that hold great potential for investigating brain structure and function. Combining these two approaches can lead to a better and more complete characterization of the brain as a network. The aim of this work is characterizing the connectome from a novel perspective using the myelination measure given by the g-ratio. The g-ratio is the ratio of the inner to the outer diameters of a myelinated axon, whose aggregated value can now be estimated in vivo using MRI...
September 13, 2017: NeuroImage
https://www.readbyqxmd.com/read/28916179/a-comparison-of-inhomogeneous-magnetization-transfer-myelin-volume-fraction-and-diffusion-tensor-imaging-measures-in-healthy-children
#4
REVIEW
Bryce L Geeraert, R Marc Lebel, Alyssa C Mah, Sean C Deoni, David C Alsop, Gopal Varma, Catherine Lebel
Sensitive and specific biomarkers of myelin can help define baseline brain health and development, identify and monitor disease pathology, and evaluate response to treatment where myelin content is affected. Diffusion measures such as radial diffusivity (RD) are commonly used to assess myelin content, but are not specific to myelin. Inhomogeneous magnetization transfer (ihMT) and multicomponent driven equilibrium single-pulse observation of T1 and T2 (mcDESPOT) offer quantitative parameters (qihMT and myelin volume fraction/VFm, respectively) which are suggested to have improved sensitivity to myelin...
September 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28915341/-31-p-magnetic-resonance-fingerprinting-for-rapid-quantification-of-creatine-kinase-reaction-rate-in-vivo
#5
Charlie Y Wang, Yuchi Liu, Shuying Huang, Mark A Griswold, Nicole Seiberlich, Xin Yu
The purpose of this work was to develop a (31) P spectroscopic magnetic resonance fingerprinting (MRF) method for fast quantification of the chemical exchange rate between phosphocreatine (PCr) and adenosine triphosphate (ATP) via creatine kinase (CK). A (31) P MRF sequence (CK-MRF) was developed to quantify the forward rate constant of ATP synthesis via CK ( kfCK), the T1 relaxation time of PCr ( T1PCr), and the PCr-to-ATP concentration ratio ( MRPCr). The CK-MRF sequence used a balanced steady-state free precession (bSSFP)-type excitation with ramped flip angles and a unique saturation scheme sensitive to the exchange between PCr and γATP...
September 15, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28862349/z-spectrum-appearance-and-interpretation-in-the-presence-of-fat-influence-of-acquisition-parameters
#6
Shu Zhang, Jochen Keupp, Xinzeng Wang, Ivan Dimitrov, Ananth J Madhuranthakam, Robert E Lenkinski, Elena Vinogradov
PURPOSE: Chemical exchange saturation transfer (CEST) MRI is increasingly evolving from brain to body applications. One of the known problems in the body imaging is the presence of strong lipid signals. Although their influence on the CEST effect is acknowledged, there was no study that focuses on the interplay among echo time, fat fraction, and Z-spectrum. This study strives to address these points, with the emphasis on the application in the breast. METHODS: Z-spectra were simulated in phase and out of phase of the main fat peak at -3...
September 1, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28861929/myelin-content-changes-in-probable-alzheimer-s-disease-and-mild-cognitive-impairment-associations-with-age-and-severity-of-neuropsychiatric-impairment
#7
Eleftherios Kavroulakis, Panagiotis G Simos, Georgios Kalaitzakis, Thomas G Maris, Dimitra Karageorgou, Ioannis Zaganas, Simeon Panagiotakis, Maria Basta, Alexandros Vgontzas, Efrosini Papadaki
BACKGROUND: Existing indices of white matter integrity such as fractional anisotropy and magnetization transfer ratio may not provide optimal specificity to myelin content. In contrast, myelin water fraction (MWF) derived from the multiecho T2 relaxation time technique may serve as a more direct measure of myelin content. PURPOSE/HYPOTHESIS: The goal of the present study was to identify markers of regional demyelination in patients with probable Alzheimer's disease (AD) and mild cognitive impairment (MCI) in relation to age and severity of neuropsychiatric impairment...
August 31, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28860625/detection-of-dynamic-substrate-binding-using-mri
#8
Nirbhay N Yadav, Xing Yang, Yuguo Li, Wenbo Li, Guanshu Liu, Peter C M van Zijl
Magnetic Resonance Imaging (MRI) is rarely used for molecular binding studies and never without synthetic metallic labels. We designed an MRI approach that can specifically detect the binding of natural substrates (i.e. no chemical labels). To accomplish such detection of substrate-target interaction only, we exploit (i) the narrow resonance of aliphatic protons in free substrate for selective radio-frequency (RF) labeling and, (ii) the process of immobilisation upon binding to a solid-like target for fast magnetic transfer of this label over protons in the target backbone...
August 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28812002/image-guided-thermal-ablation-with-mr-based-thermometry
#9
REVIEW
Mingming Zhu, Ziqi Sun, Chin K Ng
Thermal ablation techniques such as radiofrequency, microwave, high intensity focused ultrasound (HIFU) and laser have been used as minimally invasive strategies for the treatment of variety of cancers. MR thermometry methods are readily available for monitoring thermal distribution and deposition in real time, leading to decrease of incidents of normal tissue damage around targeted lesion. HIFU and laser-induced thermal therapy (LITT) are the two widely accepted tumor ablation techniques because of their compatibility with MR systems...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28799280/amide-proton-transfer-weighted-imaging-to-differentiate-malignant-from-benign-pulmonary-lesions-comparison-with-diffusion-weighted-imaging-and-fdg-pet-ct
#10
Yoshiharu Ohno, Yuji Kishida, Shinichiro Seki, Masao Yui, Mitsue Miyazaki, Hisanobu Koyama, Takeshi Yoshikawa
PURPOSE: To compare the capability of amide proton transfer-weighted (APTw) imaging, diffusion-weighted imaging (DWI), and FDG-PET/CT for the differentiation of malignant from benign pulmonary nodules. MATERIALS AND METHODS: In all, 82 consecutive patients with pulmonary nodules underwent APTw imaging and DWI with a 3T system, and FDG-PET/CT. All nodules were divided as either malignant (n = 49) or benign (n = 39) groups based on pathological and follow-up examinations...
August 11, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28792646/clinical-applications-of-chemical-exchange-saturation-transfer-cest-mri
#11
Kyle M Jones, Alyssa C Pollard, Mark D Pagel
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has been developed and employed in multiple clinical imaging research centers worldwide. Selective radiofrequency (RF) saturation pulses with standard 2D and 3D MRI acquisition schemes are now routinely performed, and CEST MRI can produce semiquantitative results using magnetization transfer ratio asymmetry (MTRasym ) analysis while accounting for B0 inhomogeneity. Faster clinical CEST MRI acquisition methods and more quantitative acquisition and analysis routines are under development...
August 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28780188/ultrashort-echo-time-t2-%C3%A2-values-decrease-in-tendons-with-application-of-static-tensile-loads
#12
Saeed Jerban, Amin Nazaran, Xin Cheng, Michael Carl, Nikolaus Szeverenyi, Jiang Du, Eric Y Chang
In early stages of tendon disease, mechanical properties may become altered prior to changes in morphological anatomy. Ultrashort echo time (UTE) magnetic resonance imaging (MRI) can be used to directly detect signal from tissues with very short T2 values, including unique viscoelastic tissues such as tendons. The purpose of this study was to use UTE sequences to measure T2(∗), T1 and magnetization transfer ratio (MTR) variations of tendon samples under static tensile loads. Six human peroneal tendons were imaged before and under static loading using UTE sequences on a clinical 3T MRI scanner...
August 16, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/28776754/quantitative-two-dimensional-ultrashort-echo-time-magnetization-transfer-2d-ute-mt-imaging-of-cortical-bone
#13
Ya-Jun Ma, Anthony Tadros, Jiang Du, Eric Y Chang
PURPOSE: To investigate quantitative 2D ultrashort echo time magnetization transfer (UTE-MT) imaging in ex vivo bovine cortical bone and in vivo human tibial cortical bone. METHODS: Data were acquired from five fresh bovine cortical bone samples and five healthy volunteer tibial cortical bones using a 2D UTE-MT sequence on a clinical 3T scanner. The 2D UTE-MT sequence used four or five MT powers with five frequency offsets. Results were analyzed with a two-pool quantitative MT model, providing measurements of macromolecular fraction (f), macromolecular proton transverse relaxation times (T2m ), proton exchange rates from water/macromolecular to the macromolecular/water pool (RM0m /RM0w ), and spin-lattice relaxation rate of water pool (R1w )...
August 3, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28774580/advancing-imaging-technologies-for-patients-with-spinal-pain-with-a-focus-on-whiplash-injury
#14
James M Elliott, Mark J Hancock, Rebecca J Crawford, Andrew C Smith, David M Walton
BACKGROUND CONTEXT: Radiological observations of soft-tissue changes that may relate to clinical symptoms in patients with traumatic and non-traumatic spinal disorders are highly controversial. Studies are often of poor quality and findings inconsistent. A plethora of evidence suggests some pathoanatomical findings from traditional imaging applications are common in asymptomatic participants across the life span, which further questions the diagnostic, prognostic, and theranostic value of traditional imaging...
July 31, 2017: Spine Journal: Official Journal of the North American Spine Society
https://www.readbyqxmd.com/read/28761809/evaluating-single-point-quantitative-magnetization-transfer-in-the-cervical-spinal-cord-application-to-multiple-sclerosis
#15
Alex K Smith, Samantha By, Bailey D Lyttle, Richard D Dortch, Bailey A Box, Lydia J Mckeithan, Saakshi Thukral, Francesca Bagnato, Siddharama Pawate, Seth A Smith
Spinal cord (SC) damage is linked to clinical deficits in patients with multiple sclerosis (MS), however, conventional MRI methods are not specific to the underlying macromolecular tissue changes that may precede overt lesion detection. Single-point quantitative magnetization transfer (qMT) is a method that can provide high-resolution indices sensitive to underlying macromolecular composition in a clinically feasible scan time by reducing the number of MT-weighted acquisitions and utilizing a two-pool model constrained by empirically determined constants...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28750205/corrigendum-to-the-physical-mechanism-of-inhomogeneous-magnetization-transfer-mri-j-magn-reson-274-2017-125-136
#16
Alan P Manning, Kimberley L Chang, Alex L MacKay, Carl A Michal
No abstract text is available yet for this article.
July 24, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28743460/high-resolution-in-vivo-imaging-of-human-locus-coeruleus-by-magnetization-transfer-mri-at-3t-and-7t
#17
Nikos Priovoulos, Heidi I L Jacobs, Dimo Ivanov, Kamil Uludag, Frans R J Verhey, Benedikt A Poser
Locus Coeruleus (LC) is a neuromelanin-rich brainstem structure that is the source of noradrenaline in the cortex and is thought to modulate attention and memory. LC imaging in vivo is commonly performed with a 2D T1-weighted Turbo Spin Echo (TSE) MRI sequence, an approach that suffers from several drawbacks at 3T, including long acquisition times and highly anisotropic spatial resolution. In this study, we developed a high-resolution Magnetization Transfer (MT) sequence for LC imaging at both 7T and 3T and compared its performance to a TSE sequence...
July 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/28736875/assessment-of-unilateral-ureter-obstruction-with-multi-parametric-mri
#18
Feng Wang, Keiko Takahashi, Hua Li, Zhongliang Zu, Ke Li, Junzhong Xu, Raymond C Harris, Takamune Takahashi, John C Gore
PURPOSE: Quantitative multi-parametric MRI (mpMRI) methods may allow the assessment of renal injury and function in a sensitive and objective manner. This study aimed to evaluate an array of MRI methods that exploit endogenous contrasts including relaxation rates, pool size ratio (PSR) derived from quantitative magnetization transfer (qMT), chemical exchange saturation transfer (CEST), nuclear Overhauser enhancement (NOE), and apparent diffusion coefficient (ADC) for their sensitivity and specificity in detecting abnormal features associated with kidney disease in a murine model of unilateral ureter obstruction (UUO)...
July 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28733991/ph-sensitive-amide-proton-transfer-effect-dominates-the-magnetization-transfer-asymmetry-contrast-during-acute-ischemia-quantification-of-multipool-contribution-to-in-vivo-cest-mri
#19
Yin Wu, Iris Yuwen Zhou, Dongshuang Lu, Emiri Manderville, Eng H Lo, Hairong Zheng, Phillip Zhe Sun
PURPOSE: To determine the origins of in vivo magnetization transfer asymmetry contrast during acute ischemic stroke, particularly in the diffusion lesion, perfusion lesion, and their mismatch using a middle cerebral artery occlusion rat model of acute stroke. METHODS: Adult male Wistar rats underwent multiparametric MRI of diffusion, perfusion, T1 , and amide proton transfer (APT) imaging at 4.7 T following a middle cerebral artery occlusion procedure. A multipool Lorentzian model, including the nuclear Overhauser effect, magnetization transfer, direct water saturation, amine and amide chemical exchange saturation transfer effects, was applied for Z-spectrum fitting to determine the sources of in vivo magnetization transfer asymmetry following acute stroke...
July 21, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28729292/amide-proton-transfer-imaging-allows-detection-of-glioma-grades-and-tumor-proliferation-comparison-with-ki-67-expression-and-proton-mr-spectroscopy-imaging
#20
C Su, C Liu, L Zhao, J Jiang, J Zhang, S Li, W Zhu, J Wang
BACKGROUND AND PURPOSE: Prognosis in glioma depends strongly on tumor grade and proliferation. In this prospective study of patients with untreated primary cerebral gliomas, we investigated whether amide proton transfer-weighted imaging could reveal tumor proliferation and reliably distinguish low-grade from high-grade gliomas compared with Ki-67 expression and proton MR spectroscopy imaging. MATERIALS AND METHODS: This study included 42 patients with low-grade (n = 28) or high-grade (n = 14) glioma, all of whom underwent conventional MR imaging, proton MR spectroscopy imaging, and amide proton transfer-weighted imaging on the same 3T scanner within 2 weeks before surgery...
July 20, 2017: AJNR. American Journal of Neuroradiology
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