Nuclear magnetic relaxation dispersion of murine tissue for development of T1 (R1) dispersion contrast imaging
This study quantified the spin–lattice relaxation rate (R1) dispersion of murine tissues from 0.24 mT to 3 T. A combination of ex vivo and in vivo spin–lattice relaxation rate measurements were acquired for murine tissue. Selected brain, liver, kidney, muscle, and fat tissues were excised and R1 dispersion profiles were acquired from 0.24 mT to 1.0 T at 37 °C, using a fast field‐cycling MR (FFC‐MR) relaxometer. In vivo R1 dispersion profiles of mice were acquired from 1.26 T to 1.74 T at 37 °C, using FFC‐MRI on a 1.5 T scanner outfitted with a field‐cycling insert electromagnet to dynamically control B...
Source: NMR in Biomedicine - October 18, 2017 Category: Radiology Authors: Yonathan T. Araya, Francisco Mart ínez‐Santiesteban, William B. Handler, Chad T. Harris, Blaine A. Chronik, Timothy J. Scholl Tags: RESEARCH ARTICLE Source Type: research
The role of magnetization transfer in the observed contrast in T1 weighted imaging under clinical setups
In T1 weighted magnetic resonance imaging of brain and spinal cord in the clinical setting, the white matter (WM) appears with greater intensity than the gray matter (GM). This contrast has been assigned to differences in T1 values. In these experiments the RF pulses are too long to excite both the water and the species with restricted motion of the protons (SRMP). In in vitro studies using short RF pulses, the contrast is reversed, with greater intensity for the GM. These results raise the question of whether magnetization transfer (MT) plays a role in the contrast observed in the T1 weighting experiments. In the present ...
Source: NMR in Biomedicine - October 18, 2017 Category: Radiology Authors: U. Eliav, G. Navon Tags: RESEARCH ARTICLE Source Type: research
Simultaneous imaging of hyperpolarized [1,4 ‐13C2]fumarate, [1‐13C]pyruvate and 18F–FDG in a rat model of necrosis in a clinical PET/MR scanner
A co‐polarization scheme for [1,4‐13C2]fumarate and [1‐13C]pyruvate is presented to simultaneously assess necrosis and metabolism in rats with hyperpolarized 13C magnetic resonance (MR). The co‐polarization was performed in a SPINlab polarizer. In addition, the feasibility of simultaneous positron emission tomography (PET) and MR of small animals with a clinical PET/MR scanner is demonstrated. The hyperpolarized metabolic MR and PET was demonstrated in a rat model of necrosis. The polarization and T1 of the co‐polarized [1,4‐13C2]fumarate and [1‐13C]pyruvate substrates were measured in vitro and compared with...
Source: NMR in Biomedicine - October 18, 2017 Category: Radiology Authors: Abubakr Eldirdiri, Andreas Clemmensen, Sean Bowen, Andreas Kj ær, Jan Henrik Ardenkjær‐Larsen Tags: RESEARCH ARTICLE Source Type: research
Issue Information
No abstract is available for this article. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - October 16, 2017 Category: Radiology Tags: ISSUE INFORMATION Source Type: research
Cover Image, Volume 30, Issue 11
The cover image, by Luis Akakpo et al., is based on the Research Article User‐independent diffusion tensor imaging analysis pipelines in a rat model presenting ventriculomegalia: A comparison study, DOI: 10.1002/nbm.3793. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - October 16, 2017 Category: Radiology Authors: Luis Akakpo, Wyston C. Pierre, Chen Jin, Ir ène Londono, Philippe Pouliot, Gregory A. Lodygensky Tags: COVER IMAGE Source Type: research
Soft tissue rheology and its implications for elastography: Challenges and opportunities
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - October 9, 2017 Category: Radiology Source Type: research
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NMR in Biomedicine, Ahead of Print. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - October 9, 2017 Category: Radiology Source Type: research
Combined endogenous MR biomarkers to predict basal tumor oxygenation and response to hyperoxic challenge
Hypoxia is a common feature of solid tumors, which translates into increased angiogenesis, malignant phenotype cell selection, change in gene expression and greater resistance to radiotherapy and chemotherapy. Therefore, there is a need for markers of hypoxia to stratify patients, in order to personalize treatment to improve therapeutic outcome. However, no modality has yet been validated for the screening of hypoxia in routine clinical practice. Magnetic resonance imaging (MRI) R1 and R2* relaxation parameters are sensitive to tissue oxygenation: R1 is sensitive to dissolved oxygen and R2* is sensitive to intravascular de...
Source: NMR in Biomedicine - October 1, 2017 Category: Radiology Authors: Thanh ‐Trang Cao‐Pham, Nicolas Joudiou, Matthias Van Hul, Caroline Bouzin, Patrice D. Cani, Bernard Gallez, Bénédicte F. Jordan Tags: RESEARCH ARTICLE Source Type: research
Soft tissue rheology and its implications for elastography: Challenges and opportunities
Abstract
Magnetic resonance elastography and related shear wave ultrasound elastography techniques can be used to estimate the mechanical properties of soft tissues in vivo by using the relationships between wave propagation and the elastic properties of materials. These techniques have found numerous clinical and research applications, tracking changes in tissue properties as a result of disease or other interventions. Most dynamic elastography approaches estimate tissue elastic (or viscoelastic) properties from a simplified version of the equations for the propagation of acoustic waves through a homogeneous linear (visco...
Source: NMR in Biomedicine - October 1, 2017 Category: Radiology Authors: Lynne E. Bilston Tags: SPECIAL ISSUE REVIEW ARTICLE Source Type: research
Characterization and stratification of prostate lesions based on comprehensive multiparametric MRI using detailed whole ‐mount histopathology as a reference standard
This study aimed to characterize prostate cancer (PCa) based on multiparametric MR (mpMR) measures and to validate mpMRI in detecting PCa and predicting PCa aggressiveness through correlations with whole‐mount histopathology. MpMRI provided excellent separation of benign tissues and PCa, and across PCa tissues of different aggressiveness in the peripheral and in the transition zones, even for small lesions. The final models prominently featured spectroscopy and dynamic contrast‐enhanced imaging metrics, underlining the value of these measures within a comprehensive mpMRI examination. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - September 30, 2017 Category: Radiology Authors: Olga Starobinets, Jeffry P. Simko, Kyle Kuchinsky, John Kornak, Peter R. Carroll, Kirsten L. Greene, John Kurhanewicz, Susan M. Noworolski Tags: RESEARCH ARTICLE Source Type: research
Investigation of the contribution of total creatine to the CEST Z ‐spectrum of brain using a knockout mouse model
The current study aims to assign and estimate the total creatine (tCr) signal contribution to the Z‐spectrum in mouse brain at 11.7 T. Creatine (Cr), phosphocreatine (PCr) and protein phantoms were used to confirm the presence of a guanidinium resonance at this field strength. Wild‐type (WT) and knockout mice with guanidinoacetate N‐methyltransferase deficiency (GAMT−/−), which have low Cr and PCr concentrations in the brain, were used to assign the tCr contribution to the Z‐spectrum. To estimate the total guanidinium concentrations, two pools for the Z‐spectrum around 2 ppm were assumed: (i) a Lorentzian f...
Source: NMR in Biomedicine - September 29, 2017 Category: Radiology Authors: Lin Chen, Haifeng Zeng, Xiang Xu, Nirbhay N. Yadav, Shuhui Cai, Nicolaas A. Puts, Peter B. Barker, Tong Li, Robert G. Weiss, Peter C.M. Zijl, Jiadi Xu Tags: RESEARCH ARTICLE Source Type: research
An eigenvalue approach for the automatic scaling of unknowns in model ‐based reconstructions: Application to real‐time phase‐contrast flow MRI
Abstract
The purpose of this work is to develop an automatic method for the scaling of unknowns in model‐based nonlinear inverse reconstructions and to evaluate its application to real‐time phase‐contrast (RT‐PC) flow magnetic resonance imaging (MRI). Model‐based MRI reconstructions of parametric maps which describe a physical or physiological function require the solution of a nonlinear inverse problem, because the list of unknowns in the extended MRI signal equation comprises multiple functional parameters and all coil sensitivity profiles. Iterative solutions therefore rely on an appropriate scaling of unknown...
Source: NMR in Biomedicine - September 28, 2017 Category: Radiology Authors: Zhengguo Tan, Thorsten Hohage, Oleksandr Kalentev, Arun A. Joseph, Xiaoqing Wang, Dirk Voit, K. Dietmar Merboldt, Jens Frahm Tags: RESEARCH ARTICLE Source Type: research
Diffusion parameter mapping with the combined intravoxel incoherent motion and kurtosis model using artificial neural networks at 3 T
Artificial neural networks (ANNs) were used for voxel‐wise parameter estimation with the combined intravoxel incoherent motion (IVIM) and kurtosis model facilitating robust diffusion parameter mapping in the human brain. The proposed ANN approach was compared with conventional least‐squares regression (LSR) and state‐of‐the‐art multi‐step fitting (LSR‐MS) in Monte‐Carlo simulations and in vivo in terms of estimation accuracy and precision, number of outliers and sensitivity in the distinction between grey (GM) and white (WM) matter. Both the proposed ANN approach and LSR‐MS yielded visually increased para...
Source: NMR in Biomedicine - September 28, 2017 Category: Radiology Authors: Marco Bertleff, Sebastian Domsch, Sebastian Weing ärtner, Jascha Zapp, Kieran O'Brien, Markus Barth, Lothar R. Schad Tags: RESEARCH ARTICLE Source Type: research
Diffusion MRI fiber tractography of the brain
The ability of fiber tractography to delineate non‐invasively the white matter fiber pathways of the brain raises possibilities for clinical applications and offers enormous potential for neuroscience. In the last decade, fiber tracking has become the method of choice to investigate quantitative MRI parameters in specific bundles of white matter. For neurosurgeons, it is quickly becoming an invaluable tool for the planning of surgery, allowing for visualization and localization of important white matter pathways before and even during surgery. Fiber tracking has also claimed a central role in the field of “connectomics...
Source: NMR in Biomedicine - September 25, 2017 Category: Radiology Authors: Ben Jeurissen, Maxime Descoteaux, Susumu Mori, Alexander Leemans Tags: SPECIAL ISSUE REVIEW ARTICLE Source Type: research
Diffusion MRI fiber tractography of the brain
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - September 25, 2017 Category: Radiology Source Type: research
