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https://www.readbyqxmd.com/read/28301086/b1-mapping-for-bias-correction-in-quantitative-t1-imaging-of-the-brain-at-3t-using-standard-pulse-sequences
#1
Mathieu Boudreau, Christine L Tardif, Nikola Stikov, John G Sled, Wayne Lee, G Bruce Pike
PURPOSE: B1 mapping is important for many quantitative imaging protocols, particularly those that include whole-brain T1 mapping using the variable flip angle (VFA) technique. However, B1 mapping sequences are not typically available on many magnetic resonance imaging (MRI) scanners. The aim of this work was to demonstrate that B1 mapping implemented using standard scanner product pulse sequences can produce B1 (and VFA T1 ) maps comparable in quality and acquisition time to advanced techniques...
March 16, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28295824/wavelet-entropy-of-bold-time-series-an-application-to-rolandic-epilepsy
#2
Lalit Gupta, Jacobus F A Jansen, Paul A M Hofman, René M H Besseling, Anton J A de Louw, Albert P Aldenkamp, Walter H Backes
PURPOSE: To assess the wavelet entropy for the characterization of intrinsic aberrant temporal irregularities in the time series of resting-state blood-oxygen-level-dependent (BOLD) signal fluctuations. Further, to evaluate the temporal irregularities (disorder/order) on a voxel-by-voxel basis in the brains of children with Rolandic epilepsy. MATERIALS AND METHODS: The BOLD time series was decomposed using the discrete wavelet transform and the wavelet entropy was calculated...
March 11, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28295820/comparison-of-readout-segmented-and-conventional-single-shot-for-echo-planar-diffusion-weighted-imaging-in-the-assessment-of-kidney-interstitial-fibrosis
#3
Iris Friedli, Lindsey Alexandra Crowe, Thomas de Perrot, Lena Berchtold, Pierre-Yves Martin, Sophie de Seigneux, Jean-Paul Vallée
PURPOSE: To compare readout-segmented echo-planar imaging (EPI) (RESOLVE) to single-shot EPI (ss-EPI) diffusion-weighted imaging (DWI) for the assessment of renal interstitial fibrosis. MATERIALS AND METHODS: A phantom, eight healthy volunteers (under 30 years to avoid age-fibrosis related) and 27 chronic kidney disease (CKD) patients (scheduled for kidney biopsy) were scanned (at 3T) with ss-EPI and 5-shot RESOLVE DWI (resolution: 2 × 2 × 5 mm(3) , 10 b-values)...
March 10, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28295736/diffusion-prepared-stimulated-echo-turbo-spin-echo-dpsti-tse-an-eddy-current-insensitive-sequence-for-three-dimensional-high-resolution-and-undistorted-diffusion-weighted-imaging
#4
Qinwei Zhang, Bram F Coolen, Maarten J Versluis, Gustav J Strijkers, Aart J Nederveen
In this study, we present a new three-dimensional (3D), diffusion-prepared turbo spin echo sequence based on a stimulated-echo read-out (DPsti-TSE) enabling high-resolution and undistorted diffusion-weighted imaging (DWI). A dephasing gradient in the diffusion preparation module and rephasing gradients in the turbo spin echo module create stimulated echoes, which prevent signal loss caused by eddy currents. Near to perfect agreement of apparent diffusion coefficient (ADC) values between DPsti-TSE and diffusion-weighted echo planar imaging (DW-EPI) was demonstrated in both phantom transient signal experiments and phantom imaging experiments...
March 13, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28291025/evaluation-of-reproducibility-of-diffusion-tensor-imaging-in-the-brachial-plexus-at-3-0-t
#5
Michael J Ho, Andrei Manoliu, Felix Pierre Kuhn, Bram Stieltjes, Markus Klarhöfer, Thorsten Feiweier, Magda Marcon, Gustav Andreisek
OBJECTIVE: The aim of this study was to evaluate the reproducibility of 3 T magnetic resonance imaging diffusion tensor imaging (DTI) of the brachial plexus in healthy subjects. METHODS: Ten healthy volunteers were included, and morphological and DTI sequences of the nerve roots of the brachial plexus from C5 to T1 of both sides were repeatedly acquired on a 3 T magnetic resonance system (MAGNETOM Skyra; Siemens Healthcare, Erlangen, Germany). A prototype diffusion-weighted single-shot echo-planar imaging sequence-enabling slice-specific shim adjustments was performed with b-values of 0 and 800 s/mm in 30 gradient directions, resulting in an acquisition time of about 6 minutes each in axial orientation...
March 13, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28274833/investigating-the-spatiotemporal-characteristics-of-the-deoxyhemoglobin-related-and-deoxyhemoglobin-unrelated-functional-hemodynamic-response-across-cortical-layers-in-awake-marmosets
#6
Cecil Chern-Chyi Yen, Daniel Papoti, Afonso C Silva
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has become a major tool to map neural activity. However, the spatiotemporal characteristics of the BOLD functional hemodynamic response across the cortical layers remain poorly understood. While human fMRI studies suffer from low spatiotemporal resolution, the use of anesthesia in animal models introduces confounding factors. Additionally, inflow contributions to the fMRI signal become non-negligible when short repetition times (TRs) are used...
March 6, 2017: NeuroImage
https://www.readbyqxmd.com/read/28270762/evaluation-of-field-map-and-nonlinear-registration-methods-for-correction-of-susceptibility-artifacts-in-diffusion-mri
#7
Sijia Wang, Daniel J Peterson, J C Gatenby, Wenbin Li, Thomas J Grabowski, Tara M Madhyastha
Correction of echo planar imaging (EPI)-induced distortions (called "unwarping") improves anatomical fidelity for diffusion magnetic resonance imaging (MRI) and functional imaging investigations. Commonly used unwarping methods require the acquisition of supplementary images during the scanning session. Alternatively, distortions can be corrected by nonlinear registration to a non-EPI acquired structural image. In this study, we compared reliability using two methods of unwarping: (1) nonlinear registration to a structural image using symmetric normalization (SyN) implemented in Advanced Normalization Tools (ANTs); and (2) unwarping using an acquired field map...
2017: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/28269512/distribution-aware-estimation-of-the-minimum-achievable-uncertainty-in-diffusion-tensor-imaging-dti
#8
Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi
Diffusion tensor imaging (DTI) provides exquisite sensitivity to structural and microstructural characteristics of brain tissue, and is routinely employed in advanced neuroimaging applications. DTI is commonly performed using intrinsically noisy echo-planar imaging techniques and poses high demands both on scanner performance and on in-scanner subject time, which in turn is directly related to the number of diffusion-weighting direction one requires. While DTI-derived indices such as fractional anisotropy (FA), diffusion tensor trace and anisotropy mode have proven extremely useful in characterizing disease-related aberrations, their estimation is commonly performed using fitting routines that do not properly take into account MRI noise distribution...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268519/comprehensive-reconstruction-of-multi-shot-multi-channel-diffusion-data-using-mussels
#9
Merry Mani, Vincent Magnotta, Douglas Kelley, Mathews Jacob
Echo planar imaging (EPI)-based magnetic resonance imaging (MRI) data are often corrupted by Nyquist ghost artifacts resulting from odd-even shifts of the EPI read-outs. Algorithms that corrects for the Nyquist ghost artifacts rely on calibration scans that are collected prior to the data acquisition. However, a more complex pattern of ghosting artifacts arises when diffusion-weighted data are acquired using segmented k-space EPI read-outs. The additional under-sampling present in the segmented acquisitions and the inter-shot motion during diffusion weighted acquistion cause ghosting artifacts in addition to the EPI ghosting arising from odd-even shifts...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28263425/fast-bilateral-breast-coverage-with-high-spectral-and-spatial-resolution-hiss-mri-at-3t
#10
Milica Medved, Hui Li, Hiroyuki Abe, Deepa Sheth, Gillian M Newstead, Olufunmilayo I Olopade, Maryellen L Giger, Gregory S Karczmar
PURPOSE: To develop and assess a full-coverage, sensitivity encoding (SENSE)-accelerated breast high spatial and spectral resolution (HiSS) magnetic resonance imaging (MRI) within clinically reasonable times as a potential nonenhanced MRI protocol for breast density measurement or breast cancer screening. MATERIALS AND METHODS: Sixteen women with biopsy-proven cancer or suspicious lesions, and 13 women who were healthy volunteers or were screened for breast cancer, received 3T breast MRI exams, including SENSE-accelerated HiSS MRI, which was implemented as a submillimeter spatial resolution echo-planar spectroscopic imaging (EPSI) sequence...
March 6, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28261904/high-resolution-in-vivo-diffusion-imaging-of-the-human-brain-with-generalized-slice-dithered-enhanced-resolution-simultaneous-multislice-gslider-sms
#11
Kawin Setsompop, Qiuyun Fan, Jason Stockmann, Berkin Bilgic, Susie Huang, Stephen F Cauley, Aapo Nummenmaa, Fuyixue Wang, Yogesh Rathi, Thomas Witzel, Lawrence L Wald
PURPOSE: To develop an efficient acquisition for high-resolution diffusion imaging and allow in vivo whole-brain acquisitions at 600- to 700-μm isotropic resolution. METHODS: We combine blipped-controlled aliasing in parallel imaging simultaneous multislice (SMS) with a novel slab radiofrequency (RF) encoding gSlider (generalized slice-dithered enhanced resolution) to form a signal-to-noise ratio-efficient volumetric simultaneous multislab acquisition. Here, multiple thin slabs are acquired simultaneously with controlled aliasing, and unaliased with parallel imaging...
March 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28260287/-value-of-readout-segmented-echo-planar-diffusion-imaging-on-3-0-t-mri-for-predicting-the-early-efficacy-of-concurrent-radiochemotherapy-of-advanced-stage-nasopharyngeal-carcinoma-patients
#12
C M Xu, J H Yuan, X J Chen, J R Qu, L F Wang, Y Zhao, H K Zhang, H Ge, X M Sun, X X Zhang, H L Li
Objective: To discuss the value of RESOLVE for predicting early therapeutic effect of concourrent radiochemotherapy in advanced stage nasopharngeal carcinoma patients. Methods: Sixty-eight patients with nasopharyngeal carcinoma were confirmed by pathology in Henan Cancer Hospital from June 2014 to January 2016.All patients underwent RESLOVE(b value=800 s/mm(2)) with a 3.0 T MRI scanner.The ADC value and the area of the tumor was measured before treatment and 2 weeks after treatment independently performed by two radiologists with 5 years experiences and the agreement evaluation was performed using ANOVA analysis...
February 21, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/28253268/multiband-multi-echo-imaging-of-simultaneous-oxygenation-and-flow-timeseries-for-resting-state-connectivity
#13
Alexander D Cohen, Andrew S Nencka, R Marc Lebel, Yang Wang
A novel sequence has been introduced that combines multiband imaging with a multi-echo acquisition for simultaneous high spatial resolution pseudo-continuous arterial spin labeling (ASL) and blood-oxygenation-level dependent (BOLD) echo-planar imaging (MBME ASL/BOLD). Resting-state connectivity in healthy adult subjects was assessed using this sequence. Four echoes were acquired with a multiband acceleration of four, in order to increase spatial resolution, shorten repetition time, and reduce slice-timing effects on the ASL signal...
2017: PloS One
https://www.readbyqxmd.com/read/28252868/early-diagnosis-and-severity-assessment-of-acute-pancreatitis-ap-using-mr-elastography-mre-with-spin-echo-echo-planar-imaging
#14
Yu Shi, Ying Liu, Yan-Qing Liu, Feng Gao, Jia-Hui Li, Qiu-Ju Li, Qi-Yong Guo
PURPOSE: To evaluate the accuracy of magnetic resonance elastography (MRE) in comparison to contrast-enhanced computed tomography (CE-CT) for early diagnosis and prediction of severity in acute pancreatitis (AP). MATERIALS AND METHODS: This cross-sectional prospective study included 76 patients with suspected AP who underwent both CE-CT and 3.0T MRE within 24 hours of hospital admission. Pancreatic stiffness, CT severity index (CTSI), Acute Physiology and Chronic Health Evaluation (APACHE)-II, and Bedside Index for Severity in AP (BISAP) scores were comparatively evaluated using data from the first 24 hours of admission, and diagnosis and severity of AP were confirmed according to the revised Atlanta Classification (2012)...
March 2, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28245815/fast-magnetic-resonance-spectroscopic-imaging-techniques-in-human-brain-applications-in-multiple-sclerosis
#15
REVIEW
Oun Al-Iedani, Jeannette Lechner-Scott, Karen Ribbons, Saadallah Ramadan
Multi voxel magnetic resonance spectroscopic imaging (MRSI) is an important imaging tool that combines imaging and spectroscopic techniques. MRSI of the human brain has been beneficially applied to different clinical applications in neurology, particularly in neurooncology but also in multiple sclerosis, stroke and epilepsy. However, a major challenge in conventional MRSI is the longer acquisition time required for adequate signal to be collected. Fast MRSI of the brain in vivo is an alternative approach to reduce scanning time and make MRSI more clinically suitable...
February 28, 2017: Journal of Biomedical Science
https://www.readbyqxmd.com/read/28237365/can-a-15-sec-flair-replace-conventional-flair-sequence-in-stroke-mr-protocols
#16
J Benzakoun, B Maïer, D Calvet, M Edjali, G Turc, S Lion, L Legrand, W Ben Hassen, O Naggara, J F Meder, J L Mas, C Oppenheim
BACKGROUND AND PURPOSE: Triage imaging facilitates the timely recognition of acute stroke with prognostic implications. Improvement in MR acquisition speed is needed given the extreme time constraints before treatment. We compared an ultrafast Echo-Planar FLAIR sequence (EPI-FLAIR) and a conventional FLAIR sequence (cFLAIR) for their diagnostic performances and ability to estimate the age of infarction. MATERIAL AND METHODS: Between June and August 2014, 125 consecutive patients (age 69±18 years, 48% men) admitted for a suspicion of acute (≤48-hrs) stroke were explored by both FLAIR sequences at 1...
February 22, 2017: Journal of Neuroradiology. Journal de Neuroradiologie
https://www.readbyqxmd.com/read/28227765/distribution-aware-estimation-of-the-minimum-achievable-uncertainty-in-diffusion-tensor-imaging-dti
#17
Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi, Andrea Duggento, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Maria Guerrisi, Nicola Toschi, Nicola Toschi, Maria Guerrisi, Marco Giannelli, Carlo Tessa, Simona Lanzafame, Andrea Duggento
Diffusion tensor imaging (DTI) provides exquisite sensitivity to structural and microstructural characteristics of brain tissue, and is routinely employed in advanced neuroimaging applications. DTI is commonly performed using intrinsically noisy echo-planar imaging techniques and poses high demands both on scanner performance and on in-scanner subject time, which in turn is directly related to the number of diffusion-weighting direction one requires. While DTI-derived indices such as fractional anisotropy (FA), diffusion tensor trace and anisotropy mode have proven extremely useful in characterizing disease-related aberrations, their estimation is commonly performed using fitting routines that do not properly take into account MRI noise distribution...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226693/comprehensive-reconstruction-of-multi-shot-multi-channel-diffusion-data-using-mussels
#18
Merry Mani, Vincent Magnotta, Douglas Kelley, Mathews Jacob, Merry Mani, Vincent Magnotta, Douglas Kelley, Mathews Jacob, Mathews Jacob, Vincent Magnotta, Merry Mani, Douglas Kelley
Echo planar imaging (EPI)-based magnetic resonance imaging (MRI) data are often corrupted by Nyquist ghost artifacts resulting from odd-even shifts of the EPI read-outs. Algorithms that corrects for the Nyquist ghost artifacts rely on calibration scans that are collected prior to the data acquisition. However, a more complex pattern of ghosting artifacts arises when diffusion-weighted data are acquired using segmented k-space EPI read-outs. The additional under-sampling present in the segmented acquisitions and the inter-shot motion during diffusion weighted acquistion cause ghosting artifacts in addition to the EPI ghosting arising from odd-even shifts...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28216452/water-and-lipid-diffusion-mri-using-chemical-shift-displacement-based-separation-of-lipid-tissue-split
#19
Naoki Ohno, Hirohito Kan, Tosiaki Miyati, Toshitaka Aoki, Shota Ishida, Toshifumi Gabata
PURPOSE: To obtain water and lipid diffusion-weighted images (DWIs) simultaneously, we devised a novel method utilizing chemical shift displacement-based separation of lipid tissue (SPLIT) imaging. MATERIALS AND METHODS: Single-shot diffusion echo-planar imaging without fat suppression was used and the imaging parameters were optimized to separate water and lipid DWIs by chemical shift displacement of the lipid signals along the phase-encoding direction. Using the optimized conditions, transverse DWIs at the maximum diameter of the right calf were scanned with multiple b-values in five healthy subjects...
February 16, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28207858/non-small-cell-lung-cancer-whole-lesion-histogram-analysis-of-the-apparent-diffusion-coefficient-for-assessment-of-tumor-grade-lymphovascular-invasion-and-pleural-invasion
#20
Naoko Tsuchiya, Mariko Doai, Katsuo Usuda, Hidetaka Uramoto, Hisao Tonami
PURPOSE: Investigating the diagnostic accuracy of histogram analyses of apparent diffusion coefficient (ADC) values for determining non-small cell lung cancer (NSCLC) tumor grades, lymphovascular invasion, and pleural invasion. MATERIALS AND METHODS: We studied 60 surgically diagnosed NSCLC patients. Diffusion-weighted imaging (DWI) was performed in the axial plane using a navigator-triggered single-shot, echo-planar imaging sequence with prospective acquisition correction...
2017: PloS One
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