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ultrashort echo time

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https://www.readbyqxmd.com/read/29096054/comparison-of-ferumoxytol-based-cerebral-blood-volume-estimates-using-quantitative-r1-and-r2-relaxometry
#1
Leonardo A Rivera-Rivera, Tilman Schubert, Gesine Knobloch, Patrick A Turski, Oliver Wieben, Scott B Reeder, Kevin M Johnson
PURPOSE: Cerebral perfusion is commonly assessed clinically with dynamic susceptibility contrast MRI using a bolus injection of gadolinium-based contrast agents, resulting in semi-quantitative values of cerebral blood volume (CBV). Steady-state imaging with ferumoxytol allows estimation of CBV with the potential for higher precision and accuracy. Prior CBV studies have focused on the signal disrupting T2* effects, but ferumoxytol also has high signal-enhancing T1 relaxivity. The purpose of this study was to investigate and compare CBV estimation using T1 and T2*, with the goal of understanding the contrast mechanisms and quantitative differences...
November 2, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29067730/simultaneous-qsm-and-metabolic-imaging-of-the-brain-using-spice
#2
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/29048157/paramagnetic-19-f-relaxation-enhancement-in-nickel-ii-complexes-of-n-trifluoroethyl-cyclam-derivatives-and-cell-labeling-for-19-f-mri
#3
Jan Blahut, Karel Bernášek, Andrea Gálisová, Vít Herynek, Ivana Císařová, Jan Kotek, Jan Lang, Stanislava Matějková, Petr Hermann
1,8-Bis(2,2,2-trifluoroethyl)cyclam (te2f) derivatives with two coordinating pendant arms involving methylenecarboxylic acid (H2te2f2a), methylenephosphonic acid (H4te2f2p), (2-pyridyl)methyl (te2f2py), and 2-aminoethyl arms (te2f2ae) in 4,11-positions were prepared, and their nickel(II) complexes were investigated as possible (19)F MR tracers. The solid-state structures of several synthetic intermediates, ligands, and all complexes were confirmed by X-ray diffraction analysis. The average Ni···F distances were determined to be about 5...
November 6, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29023975/motion-robust-high-resolution-3d-free-breathing-pulmonary-mri-using-dynamic-3d-image-self-navigator
#4
Wenwen Jiang, Frank Ong, Kevin M Johnson, Scott K Nagle, Thomas A Hope, Michael Lustig, Peder E Z Larson
PURPOSE: To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. METHODS: Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states...
October 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28984733/cartilage-endplate-thickness-variation-measured-by-ultrashort-echo-time-mri-is-associated-with-adjacent-disc-degeneration
#5
Britta Berg-Johansen, Misung Han, Aaron J Fields, Ellen C Liebenberg, Brandon J Lim, Peder Ez Larson, Cigdem Gunduz-Demir, Galateia J Kazakia, Roland Krug, Jeffrey C Lotz
STUDY DESIGN: A magnetic resonance imaging study of human cadaver spines. OBJECTIVE: To investigate associations between cartilage endplate (CEP) thickness and disc degeneration. SUMMARY OF BACKGROUND DATA: Damage to the CEP is associated with spinal injury and back pain. However, CEP morphology and its association with disc degeneration have not been well characterized. METHODS: Ten lumbar motion segments with varying degrees of disc degeneration were harvested from six cadaveric spines and scanned with MRI in the sagittal plane using a T2-weighted 2D sequence, a 3D ultrashort echo-time (UTE) imaging sequence, and a 3D T1ρ mapping sequence...
October 3, 2017: Spine
https://www.readbyqxmd.com/read/28971513/rapid-dual-echo-ramped-hybrid-encoding-mr-based-attenuation-correction-drhe-mrac-for-pet-mr
#6
Hyungseok Jang, Fang Liu, Tyler Bradshaw, Alan B McMillan
PURPOSE: In this study, we propose a rapid acquisition for MR-based attenuation correction (MRAC) in positron emission tomography (PET)/MR imaging, in which an ultrashort echo time (UTE) image and an out-of-phase echo image are obtained within a single rapid scan (35 s) at high spatial resolution (1 mm(3) ), which allows accurate estimation of a pseudo CT image using 4-class tissue classification (discrete bone, discrete air, continuous fat, and continuous water). METHODS: In dual-echo ramped hybrid encoding (dRHE), a UTE echo is directly followed by a second out-of-phase echo, in which hybrid spatial encoding combining single-point imaging and 3-dimensional radial frequency encoding is used to improve the quality of both images...
October 2, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28913879/short-t2-imaging-using-a-3d-double-adiabatic-inversion-recovery-prepared-ultrashort-echo-time-cones-3d-dir-ute-cones-sequence
#7
Ya-Jun Ma, Yanchun Zhu, Xing Lu, Michael Carl, Eric Y Chang, Jiang Du
PURPOSE: To investigate high contrast imaging of short T2 tissues with a three-dimensional double adiabatic inversion recovery prepared ultrashort echo time Cones (3D DIR-UTE-Cones) sequence. METHODS: The sequence used two sequential adiabatic inversion pulses to suppress signals from long T2 tissues, followed by multispoke UTE acquisition to detect signals from short T2 tissues. The two adiabatic inversion pulses are identical with a center frequency located at the water peak, but the spectral width is broad enough to cover both water and fat frequencies...
September 14, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28862351/chemical-shift-encoding-cse-for-sensitive-fluorine-19-mri-of-perfluorocarbons-with-complex-spectra
#8
Ruud B van Heeswijk, Roberto Colotti, Emeline Darçot, Jean Delacoste, Maxime Pellegrin, Davide Piccini, Diego Hernando
PURPOSE: To implement a fluorine-19 ((19) F) chemical shift encoding (CSE) approach for the sensitive imaging of molecules with multi-resonance spectra to remove their chemical shift displacement (CSD) artifacts, and to characterize its sensitivity versus established pulse sequences. METHODS: The feasibility of CSE spoiled gradient echo (GRE) and balanced steady-state free precession (bSSFP) was first demonstrated in a phantom study. The dependence of the sensitivity of CSE-bSSFP on several pulse sequence parameters was then established, after which the occurrence of out-of-plane excitation was assessed for 2D and 3D techniques...
September 1, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28833407/fully-phase-encoded-mri-near-metallic-implants-using-ultrashort-echo-times-and-broadband-excitation
#9
Curtis N Wiens, Nathan S Artz, Hyungseok Jang, Alan B McMillan, Kevin M Koch, Scott B Reeder
PURPOSE: To develop a fully phase-encoded MRI method for distortion-free imaging near metallic implants, in clinically feasible acquisition times. THEORY AND METHODS: An accelerated 3D fully phase-encoded acquisition with broadband excitation and ultrashort echo times is presented, which uses a broadband radiofrequency pulse to excite the entire off-resonance induced by the metallic implant. Furthermore, fully phase-encoded imaging is used to prevent distortions caused by frequency encoding, and to obtain ultrashort echo times for rapidly decaying signal...
August 21, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28812309/murine-pulmonary-imaging-at-7t-t2-and-t1-with-anisotropic-ute
#10
Jinbang Guo, Xuefeng Cao, Zackary I Cleveland, Jason C Woods
PURPOSE: To measure the T2* and T1 of mouse lung at 7T via anisotropic-resolution radial ultrashort echo-time imaging with ellipsoidal k-space coverage. METHODS: Ellipsoidal field-of-view was created by expanding uniform spherical k-space coverage. The effects of T2* and ellipsoidal sampling on image resolution were investigated by using point-spread-function analysis and resolution phantoms. Finally, this ellipsoidal sampling approach was used to measure the lung T2* and T1 of healthy C57BL/6 mice at the increasingly common preclinical field strength of 7T...
August 15, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28780188/ultrashort-echo-time-t2-%C3%A2-values-decrease-in-tendons-with-application-of-static-tensile-loads
#11
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
#12
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/28731616/inversion-recovery-ultrashort-echo-time-imaging-of-ultrashort-t2-tissue-components-in-ovine-brain-at-3%C3%A2-t-a-sequential-d2-o-exchange-study
#13
Shu-Juan Fan, Yajun Ma, Eric Y Chang, Graeme M Bydder, Jiang Du
Inversion recovery ultrashort echo time (IR-UTE) imaging holds the potential to directly characterize MR signals from ultrashort T2 tissue components (STCs), such as collagen in cartilage and myelin in brain. The application of IR-UTE for myelin imaging has been challenging because of the high water content in brain and the possibility that the ultrashort T2 * signals are contaminated by water protons, including those associated with myelin sheaths. This study investigated such a possibility in an ovine brain D2 O exchange model and explored the potential of IR-UTE imaging for the quantification of ultrashort T2 * signals in both white and gray matter at 3 T...
October 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28716680/three-dimensional-adiabatic-inversion-recovery-prepared-ultrashort-echo-time-cones-3d-ir-ute-cones-imaging-of-cortical-bone-in-the-hip
#14
Amin Nazaran, Michael Carl, Yajun Ma, Saeed Jerban, Yanchun Zhu, Xing Lu, Jiang Du, Eric Y Chang
PURPOSE: We present three-dimensional adiabatic inversion recovery prepared ultrashort echo time Cones (3D IR-UTE-Cones) imaging of cortical bone in the hip of healthy volunteers using a clinical 3T scanner. METHODS: A 3D IR-UTE-Cones sequence, based on a short pulse excitation followed by a 3D Cones trajectory, with a nominal TE of 32μs, was employed for high contrast morphological imaging of cortical bone in the hip of heathy volunteers. Signals from soft tissues such as muscle and marrow fat were suppressed via adiabatic inversion and signal nulling...
December 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28666972/non-destructive-nir-spectral-imaging-assessment-of-bone-water-comparison-to-mri-measurements
#15
Chamith S Rajapakse, Mugdha V Padalkar, Hee Jin Yang, Mikayel Ispiryan, Nancy Pleshko
Bone fracture risk increases with age, disease states, and with use of certain therapeutics, such as acid-suppressive drugs, steroids and high-dose bisphosphonates. Historically, investigations into factors that underlie bone fracture risk have focused on evaluation of bone mineral density (BMD). However, numerous studies have pointed to factors other than BMD that contribute to fragility, including changes in bone collagen and water. The goal of this study is to investigate the feasibility of using near infrared spectral imaging (NIRSI) to determine the spatial distribution and relative amount of water and organic components in whole cross-sections of bone, and to compare those results to those obtained using magnetic resonance imaging (MRI) methods...
October 2017: Bone
https://www.readbyqxmd.com/read/28643355/ultra-short-echo-time-images-quantify-high-liver-iron
#16
Eamon K Doyle, Kristin Toy, Bertin Valdez, Jonathan M Chia, Thomas Coates, John C Wood
PURPOSE: 1.5T gradient echo-based R2∗ estimates are standard-of-care for assessing liver iron concentration (LIC). Despite growing popularity of 3T, echo time (TE) limitations prevent 3T liver iron quantitation in the upper half of the clinical range (LIC ⪆20 mg/g). In this work, a 3D radial pulse sequence was assessed to double the dynamic range of 3T LIC estimates. THEORY AND METHODS: The minimum TE limits the dynamic range of pulse sequences to estimate R2∗...
June 22, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28570096/advanced-mri-techniques-for-the-ankle
#17
REVIEW
Palanan Siriwanarangsun, Won C Bae, Sheronda Statum, Christine B Chung
OBJECTIVE: The purposes of this article are to present a state-of-the-art routine protocol for MRI of the ankle, to provide problem-solving tools based on specific clinical indications, and to introduce principles for the implementation of ultrashort echo time MRI of the ankle, including morphologic and quantitative assessment. CONCLUSION: Ankle injury is common among both athletes and the general population, and MRI is the established noninvasive means of evaluation...
September 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28570032/free-breathing-pediatric-chest-mri-performance-of-self-navigated-golden-angle-ordered-conical-ultrashort-echo-time-acquisition
#18
Evan J Zucker, Joseph Y Cheng, Anshul Haldipur, Michael Carl, Shreyas S Vasanawala
PURPOSE: To assess the feasibility and performance of conical k-space trajectory free-breathing ultrashort echo time (UTE) chest magnetic resonance imaging (MRI) versus four-dimensional (4D) flow and effects of 50% data subsampling and soft-gated motion correction. MATERIALS AND METHODS: Thirty-two consecutive children who underwent both 4D flow and UTE ferumoxytol-enhanced chest MR (mean age: 5.4 years, range: 6 days to 15.7 years) in one 3T exam were recruited...
June 1, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28561910/assessment-of-porosity-index-of-the-femoral-neck-and-tibia-by-3d-ultra-short-echo-time-mri
#19
Min Chen, Huishu Yuan
PURPOSE: To measure the porosity index (PI) by ultrashort echo-time magnetic resonance imaging (UTE MRI) of the femoral neck and tibia; assess its correlations with age, gender, and body mass index (BMI); and analyze the PI correlations between both sites to assess whether tibial PI can reflect changes of femoral neck PI. MATERIALS AND METHODS: In all, 68 healthy men and women (mean age, 45.7 ± 15.9 years) underwent 3D UTE MRI (3.0T) of the hip and mid-shaft tibia...
May 31, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28504544/radial-ultrashort-te-imaging-removes-the-need-for-breath-holding-in-hepatic-iron-overload-quantification-by-r2-mri
#20
Aaryani Tipirneni-Sajja, Axel J Krafft, M Beth McCarville, Ralf B Loeffler, Ruitian Song, Jane S Hankins, Claudia M Hillenbrand
OBJECTIVE: The objective of this study is to evaluate radial free-breathing (FB) multiecho ultrashort TE (UTE) imaging as an alternative to Cartesian FB multiecho gradient-recalled echo (GRE) imaging for quantitative assessment of hepatic iron content (HIC) in sedated patients and subjects unable to perform breath-hold (BH) maneuvers. MATERIALS AND METHODS: FB multiecho GRE imaging and FB multiecho UTE imaging were conducted for 46 test group patients with iron overload who could not complete BH maneuvers (38 patients were sedated, and eight were not sedated) and 16 control patients who could complete BH maneuvers...
July 2017: AJR. American Journal of Roentgenology
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