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ultrashort echo time

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https://www.readbyqxmd.com/read/28219648/direct-magnitude-and-phase-imaging-of-myelin-using-ultrashort-echo-time-ute-pulse-sequences-a-feasibility-study
#1
Qun He, Yajun Ma, Shujuan Fan, Hongda Shao, Vipul Sheth, Graeme M Bydder, Jiang Du
In this paper, we aimed to investigate the feasibility of direct visualization of myelin, including myelin lipid and myelin basic protein (MBP), using two-dimensional ultrashort echo time (2D UTE) sequences and utilize phase information as a contrast mechanism in phantoms and in volunteers. The standard UTE sequence was used to detect both myelin and long T2 signal. An adiabatic inversion recovery UTE (IR-UTE) sequence was used to selectively detect myelin by suppressing signal from long T2 water protons. Magnitude and phase imaging and T2* were investigated on myelin lipid and MBP in the forms of lyophilized powders as well as paste-like phantoms with the powder mixed with D2O, and rubber phantoms as well as healthy volunteers...
February 17, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28160357/quantification-of-neonatal-lung-parenchymal-density-via-ultrashort-echo-time-mri-with-comparison-to-ct
#2
Nara S Higano, Robert J Fleck, David R Spielberg, Laura L Walkup, Andrew D Hahn, Robert P Thomen, Stephanie L Merhar, Paul S Kingma, Jean A Tkach, Sean B Fain, Jason C Woods
PURPOSE: To demonstrate that ultrashort echo time (UTE) magnetic resonance imaging (MRI) can achieve computed tomography (CT)-like quantification of lung parenchyma in free-breathing, non-sedated neonates. Because infant CTs are used sparingly, parenchymal disease evaluation via UTE MRI has potential for translational impact. MATERIALS AND METHODS: Two neonatal control cohorts without suspected pulmonary morbidities underwent either a research UTE MRI (n = 5; 1...
February 3, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28154823/ute-t2-%C3%A2-analysis-of-diseased-and-healthy-achilles-tendons-and-correlation-with-clinical-score-an-in-vivo-preliminary-study
#3
COMPARATIVE STUDY
Yang Qiao, Hong-Yue Tao, Kui Ma, Zi-Ying Wu, Jian-Xun Qu, Shuang Chen
Objective. To compare T2(⁎) value of healthy and diseased Achilles tendons (AT) with a recently introduced three-dimensional ultrashort echo time (3D-UTE) sequence and analyze the correlation between T2(⁎) value and clinical scores. Methods. Ten patients with symptomatic Achilles tendon and ten healthy volunteers were investigated with 3D-UTE sequence on a 3T magnetic resonance (MR) scanner. T2(⁎) values of four regions in Achilles tendons were calculated. The clinical outcomes of patients were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) score and Achilles Tendon Rupture Score (ATRS)...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28090666/quantitative-ultrashort-echo-time-imaging-for-assessment-of-massive-iron-overload-at-1-5-and-3-tesla
#4
Axel J Krafft, Ralf B Loeffler, Ruitian Song, Aaryani Tipirneni-Sajja, M Beth McCarville, Matthew D Robson, Jane S Hankins, Claudia M Hillenbrand
PURPOSE: Hepatic iron content (HIC) quantification via transverse relaxation rate (R2*)-MRI using multi-gradient echo (mGRE) imaging is compromised toward high HIC or at higher fields due to the rapid signal decay. Our study aims at presenting an optimized 2D ultrashort echo time (UTE) sequence for R2* quantification to overcome these limitations. METHODS: Two-dimensional UTE imaging was realized via half-pulse excitation and radial center-out sampling. The sequence includes chemically selective saturation pulses to reduce streaking artifacts from subcutaneous fat, and spatial saturation (sSAT) bands to suppress out-of-slice signals...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28090450/quantitative-magnetic-resonance-imaging-of-the-lumbar-intervertebral-discs
#5
REVIEW
Dosik Hwang, Sewon Kim, Nirusha A Abeydeera, Sheronda Statum, Koichi Masuda, Christine B Chung, Palanan Siriwanarangsun, Won C Bae
Human lumbar spine is composed of multiple tissue components that serve to provide structural stability and proper nutrition. Conventional magnetic resonance (MR) imaging techniques have been useful for evaluation of IVD, but inadequate at imaging the discovertebral junction and ligamentous tissues due primarily to their short T2 nature. Ultrashort time to echo (UTE) MR techniques acquire sufficient MR signal from these short T2 tissues, thereby allowing direct and quantitative evaluation. This article discusses the anatomy of the lumbar spine, MR techniques available for morphologic and quantitative MR evaluation of long and short T2 tissues of the lumbar spine, considerations for T2 relaxation modeling and fitting, and existing and new techniques for spine image post-processing, focusing on segmentation...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28090449/ultrashort-time-to-echo-magnetic-resonance-techniques-for-the-musculoskeletal-system
#6
REVIEW
Palanan Siriwanarangsun, Sheronda Statum, Reni Biswas, Won C Bae, Christine B Chung
Magnetic resonance (MR) imaging has been widely implemented as a non-invasive modality to investigate musculoskeletal (MSK) tissue disease, injury, and pathology. Advancements in MR sequences provide not only enhanced morphologic contrast for soft tissues, but also quantitative biochemical evaluation. Ultrashort time to echo (UTE) sequence, in particular, enables novel morphologic and quantitative evaluation of previously unseen MSK tissues. By using short minimum echo times (TE) below 1 msec, the UTE sequence can unveil short T2 properties of tissues including the deepest layers of the articular cartilage, cartilaginous endplate at the discovertebral junction, the meniscus, and the cortical bone...
December 2016: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28074498/imaging-and-t2-relaxometry-of-short-t2-connective-tissues-in-the-knee-using-ultrashort-echo-time-double-echo-steady-state-utedess
#7
Akshay S Chaudhari, Bragi Sveinsson, Catherine J Moran, Emily J McWalter, Ethan M Johnson, Tao Zhang, Garry E Gold, Brian A Hargreaves
PURPOSE: To develop a radial, double-echo steady-state (DESS) sequence with ultra-short echo-time (UTE) capabilities for T2 measurement of short-T2 tissues along with simultaneous rapid, signal-to-noise ratio (SNR)-efficient, and high-isotropic-resolution morphological knee imaging. METHODS: THe 3D radial UTE readouts were incorporated into DESS, termed UTEDESS. Multiple-echo-time UTEDESS was used for performing T2 relaxometry for short-T2 tendons, ligaments, and menisci; and for Dixon water-fat imaging...
January 11, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28051911/quantification-of-human-cortical-bone-bound-and-free-water-in-vivo-with-ultrashort-echo-time-mr-imaging-a-model-based-approach
#8
Shahrokh Abbasi-Rad, Hamidreza Saligheh Rad
Purpose To quantify free and bound water components of cortical bone with a model-based numeric approach with use of ultrashort echo time (UTE) magnetic resonance (MR) imaging in vivo in order to introduce a new predictor for age-related deterioration of cortical bone structure. Materials and Methods Human studies were compliant with HIPAA and approved by the institutional review board. Dual-repetition time three-dimensional hybrid-radial UTE imaging was performed, followed by the application of postprocessing algorithms, to quantify free and bound water parameters (concentration [ρ] and longitudinal relaxation time [T1]) of human cortical bone in vivo...
January 4, 2017: Radiology
https://www.readbyqxmd.com/read/28048790/su-f-j-112-clinical-feasibility-test-of-an-rf-pulse-based-mri-method-for-the-quantitative-fat-water-segmentation
#9
S Yee, J Wloch, M Pirkola
PURPOSE: Quantitative fat-water segmentation is important not only because of the clinical utility of fat-suppressed MRI images in better detecting lesions of clinical significance (in the midst of bright fat signal) but also because of the possible physical need, in which CT-like images based on the materials' photon attenuation properties may have to be generated from MR images; particularly, as in the case of MR-only radiation oncology environment to obtain radiation dose calculation or as in the case of hybrid PET/MR modality to obtain attenuation correction map for the quantitative PET reconstruction...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28038965/inversion-recovery-ultrashort-echo-time-magnetic-resonance-imaging-a-method-for-simultaneous-direct-detection-of-myelin-and-high-signal-demonstration-of-iron-deposition-in-the-brain-a-feasibility-study
#10
Vipul R Sheth, Shujuan Fan, Qun He, Yajun Ma, Jacopo Annese, Robert Switzer, Jody Corey-Bloom, Graeme M Bydder, Jiang Du
Multiple sclerosis (MS) causes demyelinating lesions in the white matter and increased iron deposition in the subcortical gray matter. Myelin protons have an extremely short T2* (<1ms) and are not directly detected with conventional clinical magnetic resonance (MR) imaging sequences. Iron deposition also reduces T2*, leading to reduced signal on clinical sequences. In this study we tested the hypothesis that the inversion recovery ultrashort echo time (IR-UTE) pulse sequence can directly and simultaneously image myelin and iron deposition using a clinical 3T scanner...
December 28, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27919416/a-3d-model-of-the-achilles-tendon-to-determine-the-mechanisms-underlying-nonuniform-tendon-displacements
#11
Geoffrey G Handsfield, Joshua M Inouye, Laura C Slane, Darryl G Thelen, G Wilson Miller, Silvia S Blemker
The Achilles is the thickest tendon in the body and is the primary elastic energy-storing component during running. The form and function of the human Achilles is complex: twisted structure, intratendinous interactions, and differential motor control from the triceps surae muscles make Achilles behavior difficult to intuit. Recent in vivo imaging of the Achilles has revealed nonuniform displacement patterns that are not fully understood and may result from complex architecture and musculotendon interactions...
January 25, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/27821291/development-of-ultrafast-ute-imaging-for-granular-systems
#12
Hilary T Fabich, Andrew J Sederman, Daniel J Holland
Ultrashort echo time (UTE) imaging is commonly used in medical MRI to image 'solid' types of tissue; to date it has not been widely used in engineering or materials science, in part due to the relatively long imaging times required. Here we show how the acquisition time for UTE can be reduced to enable a preliminary study of a fluidized bed, a type of reactor commonly used throughout industry containing short T2(∗) material and requiring fast imaging. We demonstrate UTE imaging of particles with a T2(∗) of only 185μs, and an image acquisition time of only 25ms...
October 29, 2016: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/27816505/advances-in-imaging-approaches-to-fracture-risk-evaluation
#13
REVIEW
Mary Kate Manhard, Jeffry S Nyman, Mark D Does
Fragility fractures are a growing problem worldwide, and current methods for diagnosing osteoporosis do not always identify individuals who require treatment to prevent a fracture and may misidentify those not a risk. Traditionally, fracture risk is assessed using dual-energy X-ray absorptiometry, which provides measurements of areal bone mineral density at sites prone to fracture. Recent advances in imaging show promise in adding new information that could improve the prediction of fracture risk in the clinic...
October 17, 2016: Translational Research: the Journal of Laboratory and Clinical Medicine
https://www.readbyqxmd.com/read/27775843/three-dimensional-ultrashort-echo-time-imaging-using-a-floret-trajectory
#14
Ryan K Robison, Ashley G Anderson, James G Pipe
PURPOSE: Three-dimensional ultrashort echo-time (UTE) imaging commonly makes use of an isotropic 3D radial projection acquisition. The FLORET sequence is proposed and evaluated as a more efficient alternative. METHODS: The properties of the FLORET trajectory are contrasted with those of a 3D radial projection trajectory. The theoretical advantages of FLORET, including greater sampling and SNR efficiency, are evaluated based upon experimental data. The effect of T2* decay on FLORET is analyzed in comparison to the 3D radial, Cones, and Density Adapted Radial trajectories...
October 24, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27742433/k-space-trajectory-mapping-and-its-application-for-ultrashort-echo-time-imaging
#15
Peter Latta, Zenon Starčuk, Marco L H Gruwel, Michael H Weber, Boguslaw Tomanek
MR images are affected by system delays and gradient field imperfections which induce discrepancies between prescribed and actual k-space trajectories. This could be even more critical for non-Cartesian data acquisitions where even a small deviation from the assumed k-space trajectory results in severe image degradation and artifacts. Knowledge of the actual k-space trajectories is therefore crucial and can be incorporated in the reconstruction of high quality non-Cartesian images. A novel MR method for the calibration of actual gradient waveforms was developed using a combination of phase encoding increments and subsequent detection of the exact time point at which the corresponding trajectory is crossing the k-space origin...
October 11, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27731948/ultrashort-echo-time-mri-biomarkers-of-asthma
#16
Khadija Sheikh, Fumin Guo, Dante P I Capaldi, Alexei Ouriadov, Rachel L Eddy, Sarah Svenningsen, Grace Parraga
PURPOSE: To develop and assess ultrashort echo-time (UTE) magnetic resonance imaging (MRI) biomarkers of lung function in asthma patients. MATERIALS AND METHODS: Thirty participants including 13 healthy volunteers and 17 asthmatics provided written informed consent to UTE and pulmonary function tests in addition to hyperpolarized-noble-gas 3T MRI and computed tomography (CT) for asthmatics only. The difference in MRI signal-intensity (SI) across four lung volumes (full-expiration, functional-residual-capacity [FRC], FRC+1L, and full-inspiration) was determined on a voxel-by-voxel basis to generate dynamic proton-density (DPD) maps...
October 12, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27726231/three-dimensional-t1-and-t2-mapping-of-human-lung-parenchyma-using-interleaved-saturation-recovery-with-dual-echo-ultrashort-echo-time-imaging-itsr-dute
#17
Neville D Gai, Ashkan A Malayeri, David A Bluemke
PURPOSE: To develop and assess a new technique for three-dimensional (3D) full lung T1 and T2* mapping using a single free breathing scan during a clinically feasible time. MATERIALS AND METHODS: A 3D stack of dual-echo ultrashort echo time (UTE) radial acquisition interleaved with and without a WET (water suppression enhanced through T1 effects) saturation pulse was used to map T1 and T2* simultaneously in a single scan. Correction for modulation due to multiple views per segment was derived...
October 11, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27699867/a-rapid-and-robust-gradient-measurement-technique-using-dynamic-single-point-imaging
#18
Hyungseok Jang, Alan B McMillan
PURPOSE: We propose a new gradient measurement technique based on dynamic single-point imaging (SPI), which allows simple, rapid, and robust measurement of k-space trajectory. METHODS: To enable gradient measurement, we utilize the variable field-of-view (FOV) property of dynamic SPI, which is dependent on gradient shape. First, one-dimensional (1D) dynamic SPI data are acquired from a targeted gradient axis, and then relative FOV scaling factors between 1D images or k-spaces at varying encoding times are found...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27699843/quantitative-ultrashort-te-imaging-of-the-short-t2-components-in-skeletal-muscle-using-an-extended-echo-subtraction-method
#19
Ericky C A Araujo, N Azzabou, A Vignaud, G Guillot, P G Carlier
PURPOSE: To introduce an ultrashort echo time (UTE) based method for quantitative mapping of short-T2 signals in skeletal muscle (SKM) in the presence of fat, with the aim of monitoring SKM fibrosis. METHODS: From a set of at least five UTE images of the same slice, a long- T2* map, a fat-fraction map, and a map of short-T2 -signal fraction are extracted. The method was validated by numerical simulations and in vitro studies on collagen solutions. Finaly, the method was applied to image the short-T2 signals in the leg of eight healthy volunteers...
October 3, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27663453/respiratory-self-gated-3d-ute-for-lung-imaging-in-small-animal-mri
#20
Marta Tibiletti, Andrea Bianchi, Åsmund Kjørstad, Stefan Wundrak, Detlef Stiller, Volker Rasche
PURPOSE: To investigate retrospective respiratory gating of three-dimensional ultrashort echo time (3D UTE) lung acquisition in free-breathing rats using k-space center self gating signal (DC-SG) and 3D image-based SG (3D-Img-SG). METHODS: Seven rats were investigated with a quasi-random 3D UTE protocol. Low-resolution time-resolved sliding-window images were reconstructed with a 3D golden-angle radial sparse parallel (GRASP) reconstruction to extract a 3D-Img-SG signal, whereas DC-SG was extracted from the center of k-space...
September 23, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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