journal
MENU ▼
Read by QxMD icon Read
search

Magnetic Resonance Imaging

journal
https://www.readbyqxmd.com/read/27919785/a-comparative-assessment-of-preclinical-chemotherapeutic-response-of-tumors-using-quantitative-non-gaussian-diffusion-mri
#1
Junzhong Xu, Ke Li, R Adam Smith, John C Waterton, Ping Zhao, Zhaohua Ding, Mark D Does, H Charles Manning, John C Gore
BACKGROUND: Diffusion-weighted MRI (DWI) signal attenuation is often not mono-exponential (i.e. non-Gaussian diffusion) with stronger diffusion weighting. Several non-Gaussian diffusion models have been developed and may provide new information or higher sensitivity compared with the conventional apparent diffusion coefficient (ADC) method. However the relative merits of these models to detect tumor therapeutic response is not fully clear. METHODS: Conventional ADC, and three widely-used non-Gaussian models, (bi-exponential, stretched exponential, and statistical model), were implemented and compared for assessing SW620 human colon cancer xenografts responding to barasertib, an agent known to induce apoptosis via polyploidy...
December 2, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27919784/a-comparison-study-between-the-saturation-recovery-t1-and-casl-mri-methods-for-quantitative-cbf-imaging
#2
Xiao Wang, Xiao-Hong Zhu, Yi Zhang, Afshin A Divani, Amanda J Murphy, Wei Chen
The saturation-recovery (SR)-T1 MRI method for quantitatively imaging cerebral blood flow (CBF) change (ΔCBF) concurrently with the blood oxygenation level dependence (BOLD) alteration has been recently developed and validated by simultaneous measurement of relative CBF change using laser Doppler flowmetry (LDF) in rats at 9.4T. In this study, ΔCBF induced by mildly transient hypercapnia and measured by the SR-T1 MRI method was rigorously compared with an established perfusion MRI method-continuous arterial spin labeling (CASL) approach in normal and preclinical middle cerebral artery occlusion (MCAo) rat models...
December 2, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27916658/referenceless-one-dimensional-nyquist-ghost-correction-in-multicoil-single-shot-spatiotemporally-encoded-mri
#3
Ying Chen, Yupeng Liao, Lisha Yuan, Hui Liu, Seong Dae Yun, Nadim Joni Shah, Zhong Chen, Jianhui Zhong
Single-shot spatiotemporally encoded (SPEN) MRI is a novel fast imaging method capable of retaining the time efficiency of single-shot echo planar imaging (EPI) but with distortion artifacts significantly reduced. Akin to EPI, the phase inconsistencies between mismatched even and odd echoes also result in the so-called Nyquist ghosts. However, the characteristic of the SPEN signals provides the possibility of obtaining ghost-free images directly from even and odd echoes respectively, without acquiring additional reference scans...
December 1, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27916657/pharmacokinetic-analysis-and-drug-delivery-efficiency-of-the-focused-ultrasound-induced-blood-brain-barrier-opening-in-non-human-primates
#4
Gesthimani Samiotaki, Maria Eleni Karakatsani, Amanda Buch, Stephanos Papadopoulos, Shih Ying Wu, Sachin Jambawalikar, Elisa E Konofagou
PURPOSE: Focused Ultrasound (FUS) in conjunction with systemically administered microbubbles has been shown to open the Blood-Brain Barrier (BBB) locally, non-invasively and reversibly in rodents and non-human primates (NHP), suggesting the immense potential of this technique. The objective of this study entailed the investigation of the physiologic changes in the brain following the FUS-induced BBB opening and their relationship with the underlying anatomy. MATERIALS AND METHODS: Pharmacokinetic analysis was implemented in NHP's that received FUS at various acoustic pressures...
December 1, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27899333/abnormalities-of-brain-neural-circuits-related-to-obesity-a-diffusion-tensor-imaging-study
#5
Ioannis Papageorgiou, Loukas G Astrakas, Vassileios Xydis, George A Alexiou, Panagiotis Bargiotas, Loukia Tzarouchi, Anastasia K Zikou, Dimitrios N Kiortsis, Maria I Argyropoulou
PURPOSE: Increased Body-Mass-Index (BMI) has been associated with brain atrophy in both gray and white matter structures. However, little is known concerning the integrity of white matter tracts in obesity. The purpose of the study was to evaluate the pattern of changes in white matter microstructure in human adiposity. MATERIAL AND METHODS: The study included 268 participants (52 obese, 96 overweight and 120 normal-weight) that were retrospectively evaluated by Diffusion Tensor Imaging...
November 27, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27899332/artificial-neural-network-for-suppression-of-banding-artifacts-in-balanced-steady-state-free-precession-mri
#6
Ki Hwan Kim, Sung-Hong Park
The balanced steady-state free precession (bSSFP) MR sequence is frequently used in clinics, but is sensitive to off-resonance effects, which can cause banding artifacts. Often multiple bSSFP datasets are acquired at different phase cycling (PC) angles and then combined in a special way for banding artifact suppression. Many strategies of combining the datasets have been suggested for banding artifact suppression, but there are still limitations in their performance, especially when the number of phase-cycled bSSFP datasets is small...
November 27, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27899331/comparison-of-7t-and-3t-mri-in-patients-with-moyamoya-disease
#7
Byeong Ho Oh, Hyeong Cheol Moon, Hyeon Man Baek, Youn Joo Lee, Sang Woo Kim, Young Jai Jeon, Gun Seok Lee, Hong Rae Kim, Jai Ho Choi, Kyung Soo Min, Mou Seop Lee, Young Gyu Kim, Dong Ho Kim, Won Seop Kim, Young Seok Park
Magnetic resonance imaging and magnetic resonance angiography (MRI/MRA) are widely used for evaluating the moyamoya disease (MMD). This study compared the diagnostic accuracy of 7Tesla (T) and 3T MRI/MRA in MMD. In this case control study, 12 patients [median age: 34years; range (10-66years)] with MMD and 12 healthy controls [median age: 25years; range (22-59years)] underwent both 7T and 3T MRI/MRA. To evaluate the accuracy of MRI/MRA in MMD, five criteria were compared between imaging systems of 7T and 3T: Suzuki grading system, internal carotid artery (ICA) diameter, ivy sign, flow void of the basal ganglia on T2-weighted images, and high signal intensity areas of the basal ganglia on time-of-flight (TOF) source images...
November 27, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27899330/mr-visible-localization-device-for-radiographic-pathologic-correlation-of-surgical-specimens
#8
Sonja Kinner, Tilman B Schubert, Elisabetta A Nocerino, Shannon Hynes, Timothy J Colgan, Agnes G Loeffler, Christopher Brace, Scott B Reeder, Emily Winslow
PURPOSE: The detection of small parenchymal hepatic lesions identified by preoperative imaging remains a challenge for traditional pathologic methods in large specimens. We developed a magnetic resonance imaging (MRI) compatible localization device for imaging of surgical specimens aimed to improve identification and localization of hepatic lesions ex vivo. MATERIALS AND METHODS: The device consists of two stationary and one removable MR-visible grids lined with silicone gel, creating an orthogonal 3D matrix for lesion localization...
November 27, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27890779/fast-triple-spin-echo-dixon-ftsed-sequence-for-water-and-fat-imaging
#9
Radim Korinek, Karel Bartusek, Zenon Starcuk
A number of 'Dixon' techniques based on fast spin echo (FSE) sequence have been proposed and successfully used in many branches of medicine. Some require only one scan, but most of them need multiple scans and long scan times. This article describes a new fast triple-spin-echo Dixon (FTSED) technique suitable for ultra-high field MRI, in which three specific time shifts are introduced in the echo train; thus, three images with defined water-fat phase-differences (0, π, 2π) are encoded in the phase of the acquired images without extreme restrictions upon the echo duration...
November 24, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27890778/investigating-the-spatial-specificity-of-s2-ssfp-fmri-a-monte-carlo-simulation-approach
#10
Mahdi Khajehim, Abbas Nasiraei Moghaddam
The desirable spatial specificity of spin echo (SE) fMRI cannot be efficiently utilized in high fields due to specific absorption rate (SAR) and B1 inhomogeneity problems. Consequently, S2-SSFP fMRI has been suggested as an alternative to mitigate these problems. Nevertheless, no accurate analysis has been performed thus far to evaluate spatial specificity of this technique. To study spatial specificity, we performed Monte Carlo simulations for evaluating the micro-vasculature contribution in functional contrast along with vessel size sensitivity estimations for a range of relevant imaging parameters...
November 24, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27889621/identifying-non-toxic-doses-of-manganese-for-manganese-enhanced-magnetic-resonance-imaging-to-map-brain-areas-activated-by-operant-behavior-in-trained-rats
#11
Rita Gálosi, Csaba Szalay, Mihály Aradi, Gábor Perlaki, József Pál, Roy Steier, László Lénárd, Zoltán Karádi
Manganese-enhanced magnetic resonance imaging (MEMRI) offers unique advantages such as studying brain activation in freely moving rats, but its usefulness has not been previously evaluated during operant behavior training. Manganese in a form of MnCl2, at a dose of 20mg/kg, was intraperitoneally infused. The administration was repeated and separated by 24h to reach the dose of 40mg/kg or 60mg/kg, respectively. Hepatotoxicity of the MnCl2 was evaluated by determining serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, albumin and protein levels...
November 24, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27888153/three-dimensional-black-blood-t2-mapping-with-compressed-sensing-and-data-driven-parallel-imaging-in-the-carotid-artery
#12
Jianmin Yuan, Ammara Usman, Scott A Reid, Kevin F King, Andrew J Patterson, Jonathan H Gillard, Martin J Graves
PURPOSE: To develop a 3D black-blood T2 mapping sequence with a combination of compressed sensing (CS) and parallel imaging (PI) for carotid wall imaging. MATERIALS AND METHODS: A 3D black-blood fast-spin-echo (FSE) sequence for T2 mapping with CS and PI was developed and validated. Phantom experiments were performed to assess T2 accuracy using a Eurospin Test Object, with different combination of CS and PI acceleration factors. A 2D multi-echo FSE sequence was used as a reference to evaluate the accuracy...
November 22, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27876569/o-space-with-high-resolution-readouts-outperforms-radial-imaging
#13
Haifeng Wang, Leo Tam, Emre Kopanoglu, Dana C Peters, R Todd Constable, Gigi Galiana
PURPOSE: While O-Space imaging is well known to accelerate image acquisition beyond traditional Cartesian sampling, its advantages compared to undersampled radial imaging, the linear trajectory most akin to O-Space imaging, have not been detailed. In addition, previous studies have focused on ultrafast imaging with very high acceleration factors and relatively low resolution. The purpose of this work is to directly compare O-Space and radial imaging in their potential to deliver highly undersampled images of high resolution and minimal artifacts, as needed for diagnostic applications...
November 20, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27871865/iterative-reconstruction-of-radially-sampled-31-p-bssfp-data-using-prior-information-from-1-h-mri
#14
Kristian Rink, Nadia Benkhedah, Moritz C Berger, Christine Gnahm, Nicolas G R Behl, Jonathan M Lommen, Vanessa Stahl, Peter Bachert, Mark E Ladd, Armin M Nagel
The purpose of this study is to improve direct phosphorus ((31)P) MR imaging. Therefore, 3D density-adapted radially-sampled balanced steady-state free precession (bSSFP) sequences were developed and an iterative approach exploiting additional anatomical information from hydrogen ((1)H) data was evaluated. Three healthy volunteers were examined at B0=7T in order to obtain the spatial distribution of the phosphocreatine (PCr) intensities in the human calf muscle with a nominal isotropic resolution of 10mm in an acquisition time of 10min...
November 19, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27867053/intra-voxel-analysis-in-magnetic-resonance-imaging
#15
Michele Ambrosanio, Fabio Baselice, Giampaolo Ferraioli, Flavia Lenti, Vito Pascazio
A technique for analyzing the composition of each voxel, in the magnetic resonance imaging (MRI) framework, is presented. By combining different acquisitions, a novel methodology, called intra voxel analysis (IVA), for the detection of multiple tissues and the estimation of their spin-spin relaxation times is proposed. The methodology exploits the sparse Bayesian learning (SBL) approach in order to solve a highly underdetermined problem imposing the solution sparsity. IVA, developed for spin echo imaging sequence, can be easily extended to any acquisition scheme...
November 17, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27867052/accelerating-mri-fat-quantification-using-a-signal-model-based-dictionary-to-assess-gastric-fat-volume-and-distribution-of-fat-fraction
#16
Dian Liu, Andreas Steingoetter, Helen L Parker, Jelena Curcic, Sebastian Kozerke
To quantify intragastric fat volume and distribution with accelerated magnetic resonance (MR) imaging using signal model-based dictionaries (DICT) in comparison to conventional parallel imaging (CG-SENSE). This study was approved by the local ethics committee and written informed consent was obtained. Seven healthy subjects were imaged after intake of a lipid emulsion and data at three different time points during the gastric emptying process was acquired in order to cover a range of fat fractions. Fully sampled and prospectively undersampled image data at a reduction factor of 4 were acquired using a multi gradient echo sequence at 1...
November 17, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27864008/renal-plasma-flow-rpf-measured-with-multiple-inversion-time-arterial-spin-labeling-asl-and-tracer-kinetic-analysis-validation-against-a-dynamic-contrast-enhancement-method
#17
Christopher C Conlin, Niels Oesingmann, Bradley Bolster, Yufeng Huang, Vivian S Lee, Jeff L Zhang
PURPOSE: To propose and validate a method for accurately quantifying renal plasma flow (RPF) with arterial spin labeling (ASL). MATERIALS AND METHODS: The proposed method employs a tracer-kinetic approach and derives perfusion from the slope of the ASL difference signal sampled at multiple inversion-times (TIs). To validate the method's accuracy, we performed a HIPAA-compliant and IRB-approved study with 15 subjects (9 male, 6 female; age range 24-73) to compare RPF estimates obtained from ASL to those from a more established dynamic contrast-enhanced (DCE) MRI method...
November 15, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27856399/enhanced-laws-textures-a-potential-mri-surrogate-marker-of-hepatic-fibrosis-in-a-murine-model
#18
Baojun Li, Hernan Jara, Heishun Yu, Michael O'Brien, Jorge Soto, Stephan W Anderson
PURPOSE: To compare enhanced Laws textures derived from parametric proton density (PD) maps to other MRI surrogate markers (T2, PD, apparent diffusion coefficient (ADC)) in assessing degrees of liver fibrosis in an ex vivo murine model of hepatic fibrosis imaged using 11.7T MRI. METHODS: This animal study was IACUC approved. Fourteen male, C57BL/6 mice were divided into control and experimental groups. The latter were fed a 3,5-dicarbethoxy-1,4-dihydrocollidine (DDC) supplemented diet to induce hepatic fibrosis...
November 14, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27856398/recovery-of-accurate-t2-from-historical-1-5-tesla-proton-density-and-t2-weighted-images-application-to-7-year-t2-changes-in-multiple-sclerosis-brain
#19
Md Nasir Uddin, Kelly C McPhee, Gregg Blevins, Alan H Wilman
OBJECTIVE: To determine accurate quantitative transverse relaxation times (T2) using retrospective clinical images and apply it to examine 7-year changes in multiple sclerosis (MS) brain. METHODS: A method for T2 mapping from retrospective proton density (PD) and T2-weighted fast spin echo images was recently introduced, but requires measurement of flip angles. We examined whether 1.5T flip angle variation in brain can be predicted, thus enabling T2 analysis of historical PD and T2-weighted images without a concurrent flip angle map...
November 14, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27845245/mr-elastography-of-hepatocellular-carcinoma-correlation-of-tumor-stiffness-with-histopathology-features-preliminary-findings
#20
Scott M Thompson, Jin Wang, Vishal S Chandan, Kevin J Glaser, Lewis R Roberts, Richard L Ehman, Sudhakar K Venkatesh
PURPOSE: To determine if tumor stiffness by MR Elastography (MRE) is associated with hepatocellular carcinoma (HCC) pathologic features. MATERIAL AND METHODS: A retrospective review was undertaken of all patients with pathologically confirmed HCC who underwent MRE prior to loco-regional therapy, surgical resection or transplant between 1/1/2007 to 12/31/2015. An independent observer measured tumor stiffness (kilopascals, kPa) by drawing regions of interest (ROI) covering the HCC and in the case of HCCs with non-enhancing/necrotic components, only the solid portion was included in the ROI...
November 11, 2016: Magnetic Resonance Imaging
journal
journal
28440
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"