Renal parenchyma impairment characterization in partial unilateral ureteral obstruction in mice with intravoxel incoherent motion ‐MRI
Ureteropelvic junction obstruction constitutes a major cause of progressive pediatric renal disease. The biological mechanisms underlying the renal response to obstruction can be investigated using a clinically relevant mouse model of partial unilateral ureteral obstruction (pUUO). Renal function and kidney morphology data can be evaluated using renal ultrasound, scintigraphy and uro‐magnetic resonance imaging (uro‐MRI), but these methods are poorly linked to histological change and not all are quantitative. Here, we propose to investigate pUUO for the first time using an intravoxel incoherent motion diffusion sequence...
Source: NMR in Biomedicine - November 27, 2017 Category: Radiology Authors: Maguelonne Pons, Benjamin Leporq, Liza Ali, Marianne Alison, Miguel Albuquerque, Michel Peuchmaur, Marie ‐Laurence Poli Mérol, Ulrich Blank, Simon A. Lambert, Alaa El Ghoneimi Tags: RESEARCH ARTICLE Source Type: research
Spring –damper equivalents of the fractional, poroelastic, and poroviscoelastic models for elastography
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 27, 2017 Category: Radiology Source Type: research
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NMR in Biomedicine, Ahead of Print. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 27, 2017 Category: Radiology Source Type: research
Spring –damper equivalents of the fractional, poroelastic, and poroviscoelastic models for elastography
In MR elastography, it is common to use an elastic model for the tissue's response in order to interpret the results properly. More complex models, such as viscoelastic, fractional viscoelastic, poroelastic, or poroviscoelastic ones, are also used. These models appear at first sight to be very different, but here it is shown that they may all be expressed in terms of elementary viscoelastic models.
For a medium expressed with fractional models, many elementary spring–damper combinations are added, each of them weighted according to a long‐tailed distribution of time constants or relaxation frequencies. This may open up...
Source: NMR in Biomedicine - November 27, 2017 Category: Radiology Authors: Sverre Holm Tags: SPECIAL ISSUE RESEARCH ARTICLE Source Type: research
Visualization of calcium phosphate cement in teeth by zero echo time 1H MRI at high field
In this study, we demonstrated that zero echo time (ZTE) magnetic resonance imaging (MRI) can provide excellent image contrast for calcium phosphate cement (CPC) material restored in human teeth, and can also be used to follow longitudinally the degradation of CPC in teeth in vivo. We also evaluated the MR relaxation properties of CPC and dental tissues (i.e. dentin and enamel), and found that the newly proposed Gaussian augmentation of the mono‐exponential (GAME) model performed better than the mono‐exponential (ME) model for T2* fitting. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 21, 2017 Category: Radiology Authors: Weiqiang Dou, Simone Mastrogiacomo, Andor Veltien, Hamdan S. Alghamdi, X. Frank Walboomers, Arend Heerschap Tags: RESEARCH ARTICLE Source Type: research
Transit time mapping in the mouse brain using time ‐encoded pCASL
In conclusion, this study shows the successful implementation of te‐pCASL in mice, making it possible, for the first time, to measure ATT in mice in a time‐efficient manner.
With time‐encoded pseudo‐continuous arterial spin labeling (te‐pCASL), time‐efficient multi‐delay sampling can be performed to estimate the arrival of the arterial spin labeling (ASL) signal in the brain. In this study, we show the successful implementation of a Hadamard‐12‐encoded pCASL sequence in mice, yielding perfusion‐weighted images at 11 time points (a). By fitting a perfusion model to the ASL signal time course (b), the ar...
Source: NMR in Biomedicine - November 21, 2017 Category: Radiology Authors: Lydiane Hirschler, Leon P. Munting, Artem Khmelinskii, Wouter M. Teeuwisse, Ernst Suidgeest, Jan M. Warnking, Louise Weerd, Emmanuel L. Barbier, Matthias J.P. Osch Tags: RESEARCH ARTICLE Source Type: research
Advances in computational and statistical diffusion MRI
Computational methods are crucial for the analysis of diffusion magnetic resonance imaging (MRI) of the brain. Computational diffusion MRI can provide rich information at many size scales, including local microstructure measures such as diffusion anisotropies or apparent axon diameters, whole‐brain connectivity information that describes the brain's wiring diagram and population‐based studies in health and disease. Many of the diffusion MRI analyses performed today were not possible five, ten or twenty years ago, due to the requirements for large amounts of computer memory or processor time. In addition, mathematical f...
Source: NMR in Biomedicine - November 14, 2017 Category: Radiology Authors: Lauren J. O'Donnell, Alessandro Daducci, Demian Wassermann, Christophe Lenglet Tags: SPECIAL ISSUE REVIEW ARTICLE Source Type: research
Advances in computational and statistical diffusion MRI
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 14, 2017 Category: Radiology Source Type: research
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NMR in Biomedicine, Ahead of Print. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 14, 2017 Category: Radiology Source Type: research
Issue Information
No abstract is available for this article. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 14, 2017 Category: Radiology Tags: ISSUE INFORMATION Source Type: research
Cover Image, Volume 30, Issue 12
The cover image, by Kurt Schilling et al., is based on the Research Article Can increased spatial resolution solve the crossing fiber problem for diffusion MRI?, DOI: 10.1002/nbm.3787. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 14, 2017 Category: Radiology Authors: Kurt Schilling, Yurui Gao, Vaibhav Janve, Iwona Stepniewska, Bennett A. Landman, Adam W. Anderson Tags: COVER IMAGE Source Type: research
Quantification of GABA, glutamate and glutamine in a single measurement at 3 T using GABA‐edited MEGA‐PRESS
In this study, we investigated the reliability of the composite Glu + Gln (Glx) peak estimation and the possibility of Glu and Gln separation in GABA‐edited MEGA‐PRESS spectra. The data acquired in vivo were used to develop a quality assessment framework which identified MEGA‐PRESS spectra in which Glu and Gln could be estimated reliably. Phantoms containing Glu, Gln, GABA and N‐acetylaspartate (NAA) at different concentrations were scanned using GABA‐edited MEGA‐PRESS at 3 T. Fifty‐six sets of spectra in five brain regions were acquired from 36 healthy volunteers. Based on the Glu/Gln ratio, data were cla...
Source: NMR in Biomedicine - November 12, 2017 Category: Radiology Authors: Faezeh Sanaei Nezhad, Adriana Anton, Emilia Michou, JeYoung Jung, Laura M. Parkes, Stephen R. Williams Tags: RESEARCH ARTICLE Source Type: research
Evaluation of renal metabolic response to partial ureteral obstruction with hyperpolarized 13C MRI
In this study, we utilize hyperpolarized 13C MRI to evaluate metabolic markers in the kidneys longitudinally in a mouse model of partial unilateral ureteral obstruction (pUUO). Partial obstruction was surgically induced in the left ureter of nine adult mice, leaving the right ureter as a control. 1H and hyperpolarized [1‐13C]pyruvate MRI of the kidneys was performed 2 days prior to surgery (baseline) and at 3, 7 and 14 days post‐surgery. Images were evaluated for changes in renal pelvis volume, pyruvate, lactate and the lactate to pyruvate ratio. After 14 days, mice were sacrificed and immunohistological staining of...
Source: NMR in Biomedicine - November 12, 2017 Category: Radiology Authors: David J. Niles, Jeremy W. Gordon, Gengwen Huang, Shannon Reese, Erin B. Adamson, Arjang Djamali, Sean B. Fain Tags: RESEARCH ARTICLE Source Type: research
Sources of systematic error in proton density fat fraction (PDFF) quantification in the liver evaluated from magnitude images with different numbers of echoes
In conclusion, correction for known and expected biases in PDFF quantification in liver reduces the fitting error, decreases the dependence on the number of echoes and increases the accuracy.
This retrospective analysis of liver MRI data from 463 subjects fitted the magnitude signal versus echo time from spoiled gradient echo imaging to estimate PDFF with different numbers of echoes (from 3 to 16). Monoexponential R2* decay and a multi‐peak fat spectrum were used, as well as additional corrections for non‐exponential decay (Gaussian), number of double bonds, R2* difference between water and fat, water frequency shift ...
Source: NMR in Biomedicine - November 12, 2017 Category: Radiology Authors: Mark Bydder, Gavin Hamilton, Ludovic Rochefort, Ajinkya Desai, Elhamy R. Heba, Rohit Loomba, Jeffrey B. Schwimmer, Nikolaus M. Szeverenyi, Claude B. Sirlin Tags: RESEARCH ARTICLE Source Type: research
Electro ‐optic probe for real‐time assessments of RF electric field produced in an MRI scanner: Feasibility tests at 3 and 4.7 T
During magnetic resonance imaging (MRI) examinations, the average specific absorption rate (SAR) of the whole body is calculated as an index of global energy deposition in biological tissue without taking into account the presence of metallic implants or conductive materials. However, this global SAR calculation is not sufficient to ensure patient safety and a local SAR measurement should be carried out. Several measurement techniques have already been used to evaluate the local SAR, in particular electric field (E‐field) probes, but the accuracy of the measurements and the resolutions (spatial and temporal) depend stron...
Source: NMR in Biomedicine - November 12, 2017 Category: Radiology Authors: Isabelle Saniour, Gwena ël Gaborit, Anne‐Laure Perrier, Laurane Gillette, Guillaume Revillod, Raphaël Sablong, Lionel Duvillaret, Olivier Beuf Tags: RESEARCH ARTICLE Source Type: research
