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Relaxometry

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https://www.readbyqxmd.com/read/28528429/myocardial-edema-in-acute-myocarditis-relationship-of-t2-relaxometry-and-late-enhancement-burden-by-using-dual-contrast-turbo-spin-echo-mri
#1
A Mayr, G Klug, H J Feistritzer, S J Reinstadler, M Reindl, R Esterhammer, G Feuchtner, B Metzler, M F Schocke
To quantify myocardial edema by using a T2 relaxometry approach with a dual-contrast turbo spin-echo (dcTSE) sequence in patients with acute myocarditis regarding focal late gadolinium enhancement (LGE) burden. CMR T2 relaxometry was performed in 39 patients (age 41 ± 19 years; 36% women) with LGE in a typical myocarditis pattern and in ten healthy volunteers (age 46 ± 12; 60% woman). dcTSE sequence (echo time 29 and 75 ms, respectively) was used for T2 mapping, analysis were performed on the basis of region of interest (ROI)...
May 20, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28524543/snapshot-whole-brain-t1-relaxometry-using-steady-state-prepared-spiral-multislice-variable-flip-angle-imaging
#2
Rahel Heule, Josef Pfeuffer, Oliver Bieri
PURPOSE: Variable flip angle (VFA) imaging is widely used for whole-brain T1 quantification. Because of the requirement to acquire at least two sets of MR images at different flip angles, VFA relaxometry is relatively slow. Here, whole-brain VFA T1 mapping at 1.5 T is accelerated by using efficient spiral non-Cartesian imaging METHODS: To quantify T1 in the human brain, radiofrequency spoiled gradient-echo imaging is performed at two optimized flip angles using an interleaved 2D multislice sequence with high spoiling efficiency...
May 19, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28520198/dynamic-and-steady-state-oxygen-dependent-lung-relaxometry-using-inversion-recovery-ultra-fast-steady-state-free-precession-imaging-at-1-5-t
#3
Grzegorz Bauman, Orso Pusterla, Francesco Santini, Oliver Bieri
PURPOSE: To demonstrate the feasibility of oxygen-dependent relaxometry in human lung using an inversion recovery ultra-fast steady-state free precession (IR-ufSSFP) technique. METHODS: Electrocardiogram-triggered pulmonary relaxometry with IR-ufSSFP was performed in 7 healthy human subjects at 1.5 T. The data were acquired under both normoxic and hyperoxic conditions. In a single breath-hold of less than 9 seconds, 30 transient state IR-ufSSFP images were acquired, yielding longitudinal (T1) and transversal (T2) relaxometry parameter maps using voxel-wise nonlinear fitting...
May 18, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28508110/joint-non-uniform-sampling-of-all-incremented-time-delays-for-quicker-acquisition-in-protein-relaxation-studies
#4
Mateusz Urbańczyk, Michał Nowakowski, Wiktor Koźmiński, Krzysztof Kazimierczuk
NMR relaxometry plays crucial role in studies of protein dynamics. The measurement of longitudinal and transverse relaxation rates of [Formula: see text]N is the main source of information on backbone motions. However, even the most basic approach exploiting a series of [Formula: see text]N HSQC spectra can require several hours of measurement time. Standard non-uniform sampling (NUS), i.e. random under-sampling of indirect time domain, typically cannot reduce this by more than 2-4[Formula: see text] due to relatively low "compressibility" of these spectra...
May 15, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28504137/gelation-of-na-alginate-aqueous-solution-a-study-of-sodium-ion-dynamics-via-nmr-relaxometry
#5
Congxian Zhao, Chao Zhang, Hongliang Kang, Yanzhi Xia, Kunyan Sui, Ruigang Liu
Sodium alginate (SA) hydrogels have a wide range of applications including tissue engineering, drug delivery and formulations for preventing gastric reflux. The dynamics of sodium ions during the gelation process of SA solution is critical for clarification of the gelation procedure. In this work, nuclear magnetic resonance (NMR) relaxometry and pulsed-field-gradient (PFG) NMR diffusometry were used to investigate the dynamics of the sodium ions during the gelation of SA alginate. We find that sodium ions are in two different states with the addition of divalent calcium ions, corresponding to Ca(2+) crosslinked and un-crosslinked regions in the hydrogels...
August 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28482173/evaluation-of-a-combination-tumor-treatment-using-thermo-triggered-liposomal-drug-delivery-and-carbon-ion-irradiation
#6
Daisuke Kokuryo, Ichio Aoki, Eiji Yuba, Kenji Kono, Sadahito Aoshima, Jeff Kershaw, Tsuneo Saga
The combination of radiotherapy with chemotherapy is one of the most promising strategies for cancer treatment. Here, a novel combination strategy utilizing carbon ion irradiation as a high-linear energy transfer (LET) radiotherapy and a thermo-triggered nanodevice is proposed, and drug accumulation in the tumor and treatment effects are evaluated using magnetic resonance imaging relaxometry and immunohistology (Ki-67, n = 15). The thermo-triggered liposomal anticancer nanodevice was administered into colon-26 tumor-grafted mice, and drug accumulation and efficacy was compared for 6 groups (n = 32) that received or did not receive the radiotherapy and thermo trigger...
April 21, 2017: Translational Research: the Journal of Laboratory and Clinical Medicine
https://www.readbyqxmd.com/read/28461021/pediatric-fontan-patients-are-at-risk-for-myocardial-fibrotic-remodeling-and-dysfunction
#7
Atsuko Kato, Eugénie Riesenkampff, Deane Yim, Shi-Joon Yoo, Mike Seed, Lars Grosse-Wortmann
BACKGROUND: Patients with single ventricle (SV) circulations are at risk for ventricular dysfunction. This study investigates whether there is evidence of increased myocardial fibrosis and myocardial dysfunction in children after the Fontan operation. METHODS: Consecutive children after the Fontan operation who underwent cardiac magnetic resonance (CMR) T1 relaxometry with a modified look-locker inversion recovery approach were included in this retrospective study...
April 22, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28456185/dynamics-of-solid-alanine-by-means-of-nuclear-magnetic-resonance-relaxometry
#8
A Kubica-Misztal, P Rochowski, M Florek-Wojciechowska, D Kruk
(1)H nuclear magnetic resonance relaxometry was applied to investigate the dynamics of l-alanine in the solid phase (powder). The experimental studies were carried out in a very broad frequency range, covering four orders of magnitude-from 4 kHz to 40 MHz (referring to the (1)H resonance frequency) in order to probe motional processes of much different time scales by a single experiment. To get access to the dynamics of different proton groups of alanine, the (1)H spin-lattice relaxation measurements were performed for non-deuterated and partially deuterated alanine...
April 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28432403/bone-marrow-fat-content-in-70-adolescent-girls-with-anorexia-nervosa-magnetic-resonance-imaging-and-magnetic-resonance-spectroscopy-assessment
#9
Kirsten Ecklund, Sridhar Vajapeyam, Robert V Mulkern, Henry A Feldman, Jennifer M O'Donnell, Amy D DiVasta, Catherine M Gordon
BACKGROUND: Adolescents and women with anorexia nervosa have increased bone marrow fat and decreased bone formation, at least in part due to hormonal changes leading to preferential stem cell differentiation to adipocytes over osteoblasts. OBJECTIVE: The purpose of this study was to evaluate marrow fat content and correlate with age and disease severity using knee MRI with T1 relaxometry (T1-R) and MR spectroscopy (MRS) in 70 adolescents with anorexia nervosa. MATERIALS AND METHODS: We enrolled 70 girls with anorexia nervosa who underwent 3-T knee MRI with coronal T1-W images, T1-R and single-voxel proton MRS at 30 and 60 ms TE...
April 22, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/28431589/t2-relaxometry-helps-prognosticate-seizure-outcome-in-patients-with-solitary-cerebral-cysticercosis
#10
Aaron de Souza, Atchayaram Nalini, Jitender Saini, Kandavel Thennarasu
OBJECTIVE: Correlate serial T2 relaxometry (T2R) values with long term seizure outcome in patients with solitary cerebral cysticercosis (SCC) in order to establish its usefulness as a prognostic marker in these patients. METHODS: Patients with new-onset seizures due to SCC were imaged serially using a pre-determined MRI protocol at enrolment and after 3, 6, 12 and 24months. T2 relaxometry was performed using a dual echo sequence with maps generated manually from the measured image intensities at the level of the lesion...
May 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28425543/in-situ-nuclear-magnetic-resonance-microimaging-of-live-biofilms-in-a-microchannel
#11
R S Renslow, M J Marshall, A E Tucker, W B Chrisler, X-Y Yu
Biofilms are comprised of microbial cells and an extracellular polymeric substance (EPS) matrix that supports interactions between community members and with the local environment. The highly hydrated EPS matrix makes the application of many biofilm visualization techniques difficult. Hence, to better visualize how biofilms interact with their environment, there is a need for imaging techniques to monitor hydrated state biofilm dynamics. We employed an in situ dynamic approach to construct label-free images of biofilms...
April 20, 2017: Analyst
https://www.readbyqxmd.com/read/28418846/drug-carrying-microbubbles-as-a-theranostic-tool-in-convection-enhanced-delivery-for-brain-tumor-therapy
#12
Pin-Yuan Chen, Chih-Kuang Yeh, Po-Hung Hsu, Chung-Yin Lin, Chiung-Yin Huang, Kuo-Chen Wei, Hao-Li Liu
Convection-enhanced delivery (CED) is a promising technique for infusing a therapeutic agent through a catheter with a pressure gradient to create bulk flow for improving drug spread into the brain. So far, gadopentetate dimeglumine (Gd-DTPA) is the most commonly applied surrogate agent for predicting drug distribution through magnetic resonance imaging (MRI). However, Gd-DTPA provides only a short observation duration, and concurrent infusion provides an indirect measure of the exact drug distribution. In this study, we propose using microbubbles as a contrast agent for MRI monitoring, and evaluate their use as a drug-carrying vehicle to directly monitor the infused drug...
March 15, 2017: Oncotarget
https://www.readbyqxmd.com/read/28405651/structure-and-dynamics-of-nh2-ch3-2-3sb2cl9-by-means-of-1-h-nmr-relaxometry-quadrupolar-relaxation-enhancement-effects
#13
M Florek-Wojciechowska, R Jakubas, D Kruk
(1)H spin-lattice relaxation experiments have been performed for [NH2(CH3)2]3Sb2Cl9 (tris(dimethylammonium)nonachlorodiantimonate(iii)) in the temperature range of 253-313 K and a broad range of frequencies - from 4 kHz to 40 MHz. From the analysis of quadrupolar relaxation enhancement effects (quadrupolar peaks) associated with (14)N nuclei, two lattice sites characterized by different electric field gradient tensors have been revealed. The (14)N quadrupolar couplings and asymmetry parameters at these sites differ by a factor of about two...
April 13, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28401643/ultrafast-compartmentalized-relaxation-time-mapping-with-linear-algebraic-modeling
#14
Yi Zhang, Xiaoyang Liu, Jinyuan Zhou, Paul A Bottomley
PURPOSE: To dramatically accelerate compartmental-average longitudinal (T1 ) and transverse (T2 ) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. METHODS: Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space...
April 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28367903/longitudinal-assessment-of-dentate-nuclei-relaxometry-during-massive-gadobutrol-exposure
#15
Enrico Tedeschi, Sirio Cocozza, Pasquale Borrelli, Lorenzo Ugga, Vincenzo Brescia Morra, Giuseppe Palma
We report the assessment of Dentate Nuclei (DN) R1 (1/T1) and R2* (1/R2*) values in a patient with relapsing-remitting Multiple Sclerosis, exposed to 22 standard (0.1 mmol/kg) doses of gadobutrol, who underwent eight relaxometric magnetic resonance (MR) measurements within two years. DN R1 did not significantly increase nor correlated with cumulative gadobutrol administration, even after a total dose of 130 ml. Likewise, DN R2* relaxometry remained unchanged. In conclusion, massive gadobutrol exposure did not induce significant DN relaxometry changes...
March 27, 2017: Magnetic Resonance in Medical Sciences: MRMS
https://www.readbyqxmd.com/read/28358656/dynamics-of-white-matter-plasticity-underlying-working-memory-training-multimodal-evidence-from-diffusion-mri-and-t2-relaxometry
#16
Claudia Metzler-Baddeley, Sonya Foley, Silvia de Santis, Cyril Charron, Adam Hampshire, Karen Caeyenberghs, Derek K Jones
Adaptive working memory (WM) training may lead to cognitive benefits that are associated with white matter plasticity in parietofrontal networks, but the underlying mechanisms remain poorly understood. We investigated white matter microstructural changes after adaptive WM training relative to a nonadaptive comparison group. Microstructural changes were studied in the superior longitudinal fasciculus, the main parietofrontal connection, and the cingulum bundle as a comparison pathway. MRI-based metrics were the myelin water fraction and longitudinal relaxation rate R1 from multicomponent T2 relaxometry (captured with the mcDESPOT approach) as proxy metrics of myelin, the restricted volume fraction from the composite hindered and restricted model of diffusion as an estimate of axon morphology, and fractional anisotropy and radial diffusivity from diffusion tensor imaging...
March 30, 2017: Journal of Cognitive Neuroscience
https://www.readbyqxmd.com/read/28338417/a-3d-tissue-printing-approach-for-validation-of-diffusion-tensor-imaging-in-skeletal-muscle
#17
David B Berry, Shangting You, John Warner, Lawrence R Frank, Shaochen Chen, Samuel R Ward
The ability to noninvasively assess skeletal muscle microstructure, which predicts function and disease, would be of significant clinical value. One method that holds this promise is diffusion tensor magnetic resonance imaging (DT-MRI), which is sensitive to the microscopic diffusion of water within tissues and has become ubiquitous in neuroimaging as a way of assessing neuronal structure and damage. However, its application to the assessment of changes in muscle microstructure associated with injury, pathology, or age remains poorly defined, because it is difficult to precisely control muscle microstructural features in vivo...
March 24, 2017: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/28317922/optical-imaging-of-localized-chemical-events-using-programmable-diamond-quantum-nanosensors
#18
Torsten Rendler, Jitka Neburkova, Ondrej Zemek, Jan Kotek, Andrea Zappe, Zhiqin Chu, Petr Cigler, Jörg Wrachtrup
Development of multifunctional nanoscale sensors working under physiological conditions enables monitoring of intracellular processes that are important for various biological and medical applications. By attaching paramagnetic gadolinium complexes to nanodiamonds (NDs) with nitrogen-vacancy (NV) centres through surface engineering, we developed a hybrid nanoscale sensor that can be adjusted to directly monitor physiological species through a proposed sensing scheme based on NV spin relaxometry. We adopt a single-step method to measure spin relaxation rates enabling time-dependent measurements on changes in pH or redox potential at a submicrometre-length scale in a microfluidic channel that mimics cellular environments...
March 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28303617/joint-system-relaxometry-jsr-and-cr%C3%A3-mer-rao-lower-bound-optimization-of-sequence-parameters-a-framework-for-enhanced-precision-of-despot-t1-and-t2-estimation
#19
Rui Pedro A G Teixeira, Shaihan J Malik, Joseph V Hajnal
PURPOSE: This study aims to increase the precision of single-compartment DESPOT relaxometry by two means: (i) a joint system relaxometry (JSR) approach that estimates parameters in a single step using all available data; and (ii) optimizing acquisition parameters by deploying a robust design tool based on the Crámer-Rao lower bound (CRLB). METHODS: Following the development of the analysis and design capabilities, phantom and four in vivo subject experiments were performed to compare directly the precision achieved with DESPOT and JSR estimation using published protocols and protocols designed using a proposed CRLB framework...
March 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28281697/measurement-and-visualization-of-tight-rock-exposed-to-co2-using-nmr-relaxometry-and-mri
#20
Haitao Wang, Zengmin Lun, Chengyuan Lv, Dongjiang Lang, Bingyu Ji, Ming Luo, Weiyi Pan, Rui Wang, Kai Gong
Understanding mechanisms of oil mobilization of tight matrix during CO2 injection is crucial for CO2 enhanced oil recovery (EOR) and sequestration engineering design. In this study exposure behavior between CO2 and tight rock of the Ordos Basin has been studied experimentally by using nuclear magnetic resonance transverse relaxation time (NMR T2) spectrum and magnetic resonance imaging (MRI) under the reservoir pressure and temperature. Quantitative analysis of recovery at the pore scale and visualization of oil mobilization are achieved...
March 10, 2017: Scientific Reports
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