keyword
MENU ▼
Read by QxMD icon Read
search

Echo planar

keyword
https://www.readbyqxmd.com/read/28806768/design-and-fabrication-of-a-realistic-anthropomorphic-heterogeneous-head-phantom-for-mr-purposes
#1
Sossena Wood, Narayanan Krishnamurthy, Tales Santini, Shailesh Raval, Nadim Farhat, John Andy Holmes, Tamer S Ibrahim
OBJECTIVE: The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications. MATERIALS AND METHODS: An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and preliminarily evaluated through an application that involves electromagnetic-tissue interactions: MRI (due to it being an available resource)...
2017: PloS One
https://www.readbyqxmd.com/read/28806322/reduced-field-of-view-diffusion-weighted-magnetic-resonance-imaging-of-the-prostate-at-3-tesla-comparison-with-standard-echo-planar-imaging-technique-for-image-quality-and-tumor-assessment
#2
Tsutomu Tamada, Justin M Ream, Ankur M Doshi, Samir S Taneja, Andrew B Rosenkrantz
OBJECTIVE: The purpose of this study was to compare image quality and tumor assessment at prostate magnetic resonance imaging (MRI) between reduced field-of-view diffusion-weighted imaging (rFOV-DWI) and standard DWI (st-DWI). METHODS: A total of 49 patients undergoing prostate MRI and MRI/ultrasound fusion-targeted biopsy were included. Examinations included st-DWI (field of view [FOV], 200 × 200 mm) and rFOV-DWI (FOV, 140 × 64 mm) using a 2-dimensional (2D) spatially-selective radiofrequency pulse and parallel transmission...
August 12, 2017: Journal of Computer Assisted Tomography
https://www.readbyqxmd.com/read/28804779/language-mapping-using-t2-prepared-bold-functional-mri-in-the-presence-of-large-susceptibility-artifacts-initial-results-in-patients-with-brain-tumor-and-epilepsy
#3
Jun Hua, Xinyuan Miao, Shruti Agarwal, Chetan Bettegowda, Alfredo Quiñones-Hinojosa, John Laterra, Peter C M Van Zijl, James J Pekar, Jay J Pillai
At present, presurgical functional mapping is the most prevalent clinical application of functional magnetic resonance imaging (fMRI). Signal dropouts and distortions caused by susceptibility effects in the current standard echo planar imaging (EPI)-based fMRI images are well-known problems and pose a major hurdle for the application of fMRI in several brain regions, many of which are related to language mapping in presurgical planning. Such artifacts are particularly problematic in patients with previous surgical resection cavities, craniotomy hardware, hemorrhage, and vascular malformation...
June 2017: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28801939/assessment-of-advanced-hepatic-mr-elastography-methods-for-susceptibility-artifact-suppression-in-clinical-patients
#4
Jin Wang, Kevin J Glaser, Tianhui Zhang, Qungang Shan, Bingjun He, Jun Chen, Meng Yin, Bogdan Dzyubak, Jennifer L Kugel, Scott A Kruse, Roger C Grimm, Sudhakar K Venkatesh, Richard L Ehman
PURPOSE: To assess the success rate, image quality, and the ability to stage liver fibrosis of a standard 2D gradient-recalled echo (GRE) and four different spin-echo (SE) magnetic resonance elastography (MRE) sequences in patients with different liver iron concentrations. MATERIALS AND METHODS: A total of 332 patients who underwent 3T MRE examinations that included liver fat and iron quantification were enrolled, including 136 patients with all five MRE techniques...
August 11, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28799090/prostate-cancer-detection-among-readers-with-different-degree-of-experience-using-ultra-high-b-value-diffusion-weighted-imaging-is-a-non-contrast-protocol-sufficient-to-detect-significant-cancer
#5
D Hausmann, N Aksöz, J von Hardenberg, T Martini, N Westhoff, S Buettner, S O Schoenberg, P Riffel
AIM: To evaluate the accuracy of a T2-weighted (T2w) - and a parallel transmit zoomed b = 2000 s/mm2 (b2000) - diffusion-weighted imaging sequence among three readers with different degrees of experience for prostate cancer (Pca) detection. METHODS: Ninety-three patients with suspected Pca were enrolled. For b2000 a two-dimensional spatially-selective RF pulse using an echo-planar transmit trajectory was applied, and the field of view (FOV) was reduced to one-third...
August 10, 2017: European Radiology
https://www.readbyqxmd.com/read/28797739/mb-swift-functional-mri-during-deep-brain-stimulation-in-rats
#6
Lauri J Lehto, Djaudat Idiyatullin, Jinjin Zhang, Lynn Utecht, Gregor Adriany, Michael Garwood, Olli Gröhn, Shalom Michaeli, Silvia Mangia
Recently introduced 3D radial MRI pulse sequence entitled Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) having inherently zero acquisition delay was used to obtain functional MRI (fMRI) contrast in rat's brain at 9.4 Tesla during deep brain stimulation (DBS). The results demonstrate that MB-SWIFT allows images free of susceptibility artefacts, and provides an excellent fMRI activation contrast in the brain. Flip angle dependence of the MB-SWIFT fMRI signal and elimination of the fMRI contrast while using saturation bands, indicate a blood flow origin of the observed fMRI contrast...
August 7, 2017: NeuroImage
https://www.readbyqxmd.com/read/28796443/relative-cerebral-blood-volume-is-a-potential-biomarker-in-late-delayed-radiation-induced-brain-injury
#7
Ying Xie, Haiwei Huang, Junjie Guo, Dongxiao Zhou
PURPOSE: To assess whether relative cerebral blood volume (rCBV) can provide information to reliably evaluate the stages of late delayed radiation-induced brain injury. MATERIALS AND METHODS: Forty patients diagnosed with late delayed radiation-induced brain injury were enrolled. The patients were examined using a 1.5T magnetic resonance imaging (MRI) system equipped with an 8-channel head coil. An echo planar imaging (EPI) sequence was used in perfusion-weighted imaging (PWI)...
August 10, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28795419/simultaneous-mr-thermometry-and-acoustic-radiation-force-imaging-using-interleaved-acquisition
#8
Joshua T de Bever, Henrik Odéen, Lorne W Hofstetter, Dennis L Parker
PURPOSE: A novel and practical method for simultaneously performing MR acoustic radiation force imaging (ARFI) and proton resonance frequency (PRF)-shift thermometry has been developed and tested. This could be an important tool for evaluating the success of MR-guided focused ultrasound procedures for which MR-thermometry measures temperature and thermal dose and MR-ARFI detects changes in tissue mechanical properties. METHODS: MR imaging was performed using a gradient recalled echo segmented echo-planar imaging pulse sequence with bipolar motion encoding gradients (MEG)...
August 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28782129/volumetric-mri-thermometry-using-a-three-dimensional-stack-of-stars-echo-planar-imaging-pulse-sequence
#9
Sumeeth V Jonathan, William A Grissom
PURPOSE: To measure temperature over a large brain volume with fine spatiotemporal resolution. METHODS: A three-dimensional stack-of-stars echo-planar imaging sequence combining echo-planar imaging and radial sampling with golden angle spacing was implemented at 3T for proton resonance frequency-shift temperature imaging. The sequence acquires a 188x188x43 image matrix with 1.5x1.5x2.75 mm(3) spatial resolution. Temperature maps were reconstructed using sensitivity encoding (SENSE) image reconstruction followed by the image domain hybrid method, and using the k-space hybrid method...
August 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28771867/motion-corrected-k-space-reconstruction-for-interleaved-epi-diffusion-imaging
#10
Zijing Dong, Fuyixue Wang, Xiaodong Ma, Erpeng Dai, Zhe Zhang, Hua Guo
PURPOSE: To develop a new approach to correct for physiological and macroscopic motion in multishot, interleaved echo-planar diffusion imaging. THEORY: This work built on the previous SPIRiT (iterative self-consistent parallel imaging reconstruction) based reconstruction for physiological motion correction in multishot diffusion-weighted imaging to account for macroscopic motion. In-plane rotation, translation correction, data rejection, and weighted combination are integrated in SPIRiT-based reconstruction to correct for ghosting artifacts, blurring, altered b-matrix, and residual artifacts caused by motion...
August 3, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28770039/globally-weaker-and-topologically-different-resting-state-connectivity-in-youth-with-autism
#11
Benjamin E Yerys, John D Herrington, Theodore D Satterthwaite, Lisa Guy, Robert T Schultz, Danielle S Bassett
BACKGROUND: There is a lack of agreement about functional connectivity differences in individuals with autism spectrum disorder (ASD). Studies using absolute strength have found reduced connectivity, while those using relative strength--a measure of system topology--reveal mostly enhanced connectivity. We hypothesized that mixed findings may be driven by the metric of functional connectivity. METHODS: Resting-state echo planar 3 T functional magnetic resonance imaging scans were acquired on a Siemens Verio Scanner from 6 to 17-year-old youth with ASD (n = 81) and a matched typically developing control group (n = 82)...
2017: Molecular Autism
https://www.readbyqxmd.com/read/28764428/diffuse-ultrasonic-backscatter-using-a-multi-gaussian-beam-model
#12
Xiongbing Li, Yongfeng Song, Andrea P Arguelles, Joseph A Turner
Diffuse ultrasonic backscatter is widely used to evaluate microstructural parameters of heterogeneous materials. Recent singly scattered response (SSR) models utilize a single-Gaussian beam (SGB) assumption which is expected to have limitations. Following a similar formalism, a model is presented using a multi-Gaussian beam (MGB) assumption to characterize the transducer beam for longitudinal-to-longitudinal scattering at normal incidence through an interface with arbitrary curvature. First, the Wigner transform of the transducer field is defined using conjugate double-layer MGB expressions...
July 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28755383/solid-bone-tumors-of-the-spine-diagnostic-performance-of-apparent-diffusion-coefficient-measured-using-diffusion-weighted-mri-using-histology-as-a-reference-standard
#13
Grazia Pozzi, Domenico Albano, Carmelo Messina, Salvatore Alessio Angileri, Asma'a Al-Mnayyis, Fabio Galbusera, Alessandro Luzzati, Giuseppe Perrucchini, Gennaro Scotto, Antonina Parafioriti, Alberto Zerbi, Luca Maria Sconfienza
PURPOSE: To assess the diagnostic performance of mean apparent diffusion coefficient (mADC) in differentiating benign from malignant bone spine tumors, using histology as a reference standard. Conventional magnetic resonance imaging (MRI) sequences have good reliability in evaluating spinal bone tumors, although some features of benign and malignant cancers may overlap, making the differential diagnosis challenging. MATERIALS AND METHODS: In all, 116 patients (62 males, 54 females; mean age 59...
July 29, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28748092/a-focused-ultrasound-treatment-system-for-moving-targets-part-i-generic-system-design-and-in-silico-first-stage-evaluation
#14
Michael Schwenke, Jan Strehlow, Daniel Demedts, Sabrina Haase, Diego Barrios Romero, Sven Rothlübbers, Caroline von Dresky, Stephan Zidowitz, Joachim Georgii, Senay Mihcin, Mario Bezzi, Christine Tanner, Giora Sat, Yoav Levy, Jürgen Jenne, Matthias Günther, Andreas Melzer, Tobias Preusser
BACKGROUND: Focused ultrasound (FUS) is entering clinical routine as a treatment option. Currently, no clinically available FUS treatment system features automated respiratory motion compensation. The required quality standards make developing such a system challenging. METHODS: A novel FUS treatment system with motion compensation is described, developed with the goal of clinical use. The system comprises a clinically available MR device and FUS transducer system...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28747522/pet-imaging-stability-measurements-during-simultaneous-pulsing-of-aggressive-mr-sequences-on-the-ge-signa-pet-mr
#15
Timothy W Deller, Mohammad Mehdi Khalighi, Floris P Jansen, Gary H Glover
The recent introduction of simultaneous whole-body PET/MR scanners has enabled new research taking advantage of the complementary information obtainable with PET and MR imaging. One such application is kinetic modeling, which requires high levels of PET quantitative stability. This challenges the task of isolating the two imaging subsystems from mutual interference. Performance measurements have previously been published demonstrating sufficient PET stability in the presence of MR pulsing for typical clinical use; however, PET stability during radiofrequency (RF)-intensive and gradient-intensive sequences has not previously been evaluated for a clinical whole-body scanner...
July 26, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28745021/the-impact-of-t1-versus-epi-spatial-normalization-templates-for-fmri-data-analyses
#16
Vince D Calhoun, Tor D Wager, Anjali Krishnan, Keri S Rosch, Karen E Seymour, Mary Beth Nebel, Stewart H Mostofsky, Prashanth Nyalakanai, Kent Kiehl
Spatial normalization of brains to a standardized space is a widely used approach for group studies in functional magnetic resonance imaging (fMRI) data. Commonly used template-based approaches are complicated by signal dropout and distortions in echo planar imaging (EPI) data. The most widely used software packages implement two common template-based strategies: (1) affine transformation of the EPI data to an EPI template followed by nonlinear registration to an EPI template (EPInorm) and (2) affine transformation of the EPI data to the anatomic image for a given subject, followed by nonlinear registration of the anatomic data to an anatomic template, which produces a transformation that is applied to the EPI data (T1norm)...
July 26, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28742733/intravoxel-incoherent-motion-model-free-determination-of-tissue-type-in-abdominal-organs-using-machine-learning
#17
Alexander Ciritsis, Cristina Rossi, Moritz C Wurnig, Valerie Phi Van, Andreas Boss
PURPOSE: For diffusion data sets including low and high b-values, the intravoxel incoherent motion model is commonly applied to characterize tissue. The aim of the present study was to show that machine learning allows a model-free approach to determine tissue type without a priori assumptions on the underlying physiology. MATERIALS AND METHODS: In 8 healthy volunteers, diffusion data sets were acquired using an echo-planar imaging sequence with 16 b-values in the range between 0 and 1000 s/mm...
July 24, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28740202/prior-knowledge-fitting-of-accelerated-five-dimensional-echo-planar-j-resolved-spectroscopic-imaging-effect-of-nonlinear-reconstruction-on-quantitation
#18
Zohaib Iqbal, Neil E Wilson, M Albert Thomas
(1)H Magnetic Resonance Spectroscopic imaging (SI) is a powerful tool capable of investigating metabolism in vivo from mul- tiple regions. However, SI techniques are time consuming, and are therefore difficult to implement clinically. By applying non-uniform sampling (NUS) and compressed sensing (CS) reconstruction, it is possible to accelerate these scans while re- taining key spectral information. One recently developed method that utilizes this type of acceleration is the five-dimensional echo planar J-resolved spectroscopic imaging (5D EP-JRESI) sequence, which is capable of obtaining two-dimensional (2D) spectra from three spatial dimensions...
July 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28736946/fast-and-reproducible-in-vivo-t1-mapping-of-the-human-cervical-spinal-cord
#19
Marco Battiston, Torben Schneider, Ferran Prados, Francesco Grussu, Marios C Yiannakas, Sebastien Ourselin, Claudia A M Gandini Wheeler-Kingshott, Rebecca S Samson
PURPOSE: To develop a fast and robust method for measuring T1 in the whole cervical spinal cord in vivo, and to assess its reproducibility. METHODS: A spatially nonselective adiabatic inversion pulse is combined with zonally oblique-magnified multislice echo-planar imaging to produce a reduced field-of-view inversion-recovery echo-planar imaging protocol. Multi- inversion time data are obtained by cycling slice order throughout sequence repetitions. Measurement of T1 is performed using 12 inversion times for a total protocol duration of 7 min...
July 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28736924/evaluation-of-spiral-acquisition-variants-for-functional-imaging-of-human-superior-colliculus-at-3t-field-strength
#20
Vimal Singh, Josef Pfeuffer, Tiejun Zhao, David Ress
PURPOSE: High-resolution functional magnetic resonance imaging of human subcortical brain structures is challenging because of their deep location in the cranium, and their comparatively weak blood oxygen level dependent responses to strong stimuli. Magnetic resonance imaging data for subcortical brain regions exhibit both low signal-to-noise ratio and low functional contrast-to-noise ratio. To overcome these challenges, this work evaluates the use of dual-echo spiral variants that combine outward and inward trajectories...
July 24, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
keyword
keyword
105873
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"