Assessing the influence of isoflurane anesthesia on cardiac metabolism using hyperpolarized [1 ‐13C]pyruvate
Isoflurane is a frequently used anesthetic in small‐animal dissolution dynamic nuclear polarization‐magnetic resonance imaging (DNP‐MRI) studies. Although the literature suggests interactions with mitochondrial metabolism, the influence of the compound on cardiac metabolism has not been assessed systematically to date. In the present study, the impact of low versus high isoflurane concentration was examined in a crossover experiment in healthy rats. The results revealed that cardiac metabolism is modulated by isoflurane concentration, showing increased [1‐13C]lactate and reduced [13C]bicarbonate production during h...
Source: NMR in Biomedicine - December 5, 2017 Category: Radiology Authors: Jonas Steinhauser, Patrick Wespi, Grzegorz Kwiatkowski, Sebastian Kozerke Tags: RESEARCH ARTICLE Source Type: research
Combination of surface and ‘vertical’ loop elements improves receive performance of a human head transceiver array at 9.4 T
Ultra‐high‐field (UHF, ≥7 T) human magnetic resonance imaging (MRI) provides undisputed advantages over low‐field MRI (≤3 T), but its development remains challenging because of numerous technical issues, including the low efficiency of transmit (Tx) radiofrequency (RF) coils caused by the increase in tissue power deposition with frequency. Tight‐fit human head transceiver (TxRx) arrays improve Tx efficiency in comparison with Tx‐only arrays, which are larger in order to fit multi‐channel receive (Rx)‐only arrays inside. A drawback of the TxRx design is that the number of elements in an array is limited ...
Source: NMR in Biomedicine - December 1, 2017 Category: Radiology Authors: N.I. Avdievich, I.A. Giapitzakis, A. Pfrommer, T. Borbath, A. Henning Tags: RESEARCH ARTICLE Source Type: research
A referenceless Nyquist ghost correction workflow for echo planar imaging of hyperpolarized [1 ‐13C]pyruvate and [1‐13C]lactate
We describe here a workflow for hyperpolarized 13C EPI that requires no reference scan. This involves the selection of a ghost‐containing background from a 13C image of a single metabolite at a single time point, the identification of phase correction coefficients that minimize signal in the selected area, and the application of these coefficients to images acquired at all time points and from all metabolites. The workflow was compared in phantom experiments with phase correction using a 13C reference scan, and yielded similar results in situations with a regular field of view (FOV), a restricted FOV and where there were...
Source: NMR in Biomedicine - December 1, 2017 Category: Radiology Authors: Jiazheng Wang, Alan J. Wright, Richard L. Hesketh, De ‐en Hu, Kevin M. Brindle Tags: RESEARCH ARTICLE Source Type: research
Impact of intratumoral heterogeneity of breast cancer tissue on quantitative metabolomics using high ‐resolution magic angle spinning 1H NMR spectroscopy
We describe the intratumoral variability of metabolite and lipid concentrations, quantified using high‐resolution magic angle spinning (HR MAS) 1H nuclear magnetic resonance (NMR) spectroscopy after multi‐core sampling of resected breast tumor tissue from three patients, and sampling of duplicate tissue cores from 15 additional breast tumors. In total, 32 metabolites were detected and quantified, and the intertumoral differences were, in general, found to be larger than the intratumoral differences, which suggests that one, or few, replicates per tumor are acceptable, supporting the feasibility of reliable cohort studi...
Source: NMR in Biomedicine - December 1, 2017 Category: Radiology Authors: Mikheil Gogiashvili, Salome Horsch, Rosemarie Marchan, Kathrin Gianmoena, Cristina Cadenas, Berno Tanner, Sabrina Naumann, Diana Ersova, Frank Lippek, J örg Rahnenführer, Jan T. Andersson, Roland Hergenröder, Jörg Lambert, Jan G. Hengstler, Karolina E Tags: RESEARCH ARTICLE Source Type: research
Increased CEST specificity for amide and fast ‐exchanging amine protons using exchange‐dependent relaxation rate
Chemical exchange saturation transfer (CEST) imaging of amides at 3.5 ppm and fast‐exchanging amines at 3 ppm provides a unique means to enhance the sensitivity of detection of, for example, proteins/peptides and neurotransmitters, respectively, and hence can provide important information on molecular composition. However, despite the high sensitivity relative to conventional magnetic resonance spectroscopy (MRS), in practice, CEST often has relatively poor specificity. For example, CEST signals are typically influenced by several confounding effects, including direct water saturation (DS), semi‐solid non‐specific ...
Source: NMR in Biomedicine - November 30, 2017 Category: Radiology Authors: Xiao ‐Yong Zhang, Feng Wang, Junzhong Xu, Daniel F. Gochberg, John C. Gore, Zhongliang Zu Tags: RESEARCH ARTICLE Source Type: research
Characterization of glioblastoma in an orthotopic mouse model with magnetic resonance elastography
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Source Type: research
Cardiovascular magnetic resonance elastography: A review
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Source Type: research
Imaging brain microstructure with diffusion MRI: practicality and applications
NMR in Biomedicine, EarlyView. (Source: NMR in Biomedicine)
Source: NMR in Biomedicine - November 29, 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 29, 2017 Category: Radiology Source Type: research
Online 1H ‐MRS measurements of time‐varying lactate production in an animal model of glioma during administration of an anti‐tumoral drug
The aims of this study were to implement a magnetic resonance spectroscopy (MRS) protocol for the online profiling of subnanomolar quantities of metabolites sampled from the extracellular fluid using implanted microdialysis and to apply this protocol in glioma‐bearing rats for the quantification of lactate concentration and the measurement of time‐varying lactate concentration during drug administration. MRS acquisitions on the brain microdialysate were performed using a home‐built, proton‐tuned, microsolenoid with an active volume of 2 μL. The microcoil was placed at the outlet of the microdialysis probe inside ...
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Authors: Yannick Cr émillieux, Roberto Salvati, Ursule Dumont, Noël Pinaud, Véronique Bouchaud, Stéphane Sanchez, Stefan Glöggler, Alan Wong Tags: RESEARCH ARTICLE Source Type: research
Imaging brain microstructure with diffusion MRI: practicality and applications
This article gives an overview of microstructure imaging of the brain with diffusion MRI and reviews the state of the art. The microstructure‐imaging paradigm aims to estimate and map microscopic properties of tissue using a model that links these properties to the voxel scale MR signal. Imaging techniques of this type are just starting to make the transition from the technical research domain to wide application in biomedical studies. We focus here on the practicalities of both implementing such techniques and using them in applications. Specifically, the article summarizes the relevant aspects of brain microanatomy and...
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Authors: Daniel C. Alexander, Tim B. Dyrby, Markus Nilsson, Hui Zhang Tags: SPECIAL ISSUE REVIEW ARTICLE Source Type: research
Cardiovascular magnetic resonance elastography: A review
Cardiovascular diseases are the leading cause of death worldwide. These cardiovascular diseases are associated with mechanical changes in the myocardium and aorta. It is known that stiffness is altered in many diseases, including the spectrum of ischemia, diastolic dysfunction, hypertension and hypertrophic cardiomyopathy. In addition, the stiffness of the aortic wall is altered in multiple diseases, including hypertension, coronary artery disease and aortic aneurysm formation. For example, in diastolic dysfunction in which the ejection fraction is preserved, stiffness can potentially be an important biomarker. Similarly, ...
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Authors: Saad Khan, Faisal Fakhouri, Waqas Majeed, Arunark Kolipaka Tags: SPECIAL ISSUE REVIEW ARTICLE Source Type: research
Characterization of glioblastoma in an orthotopic mouse model with magnetic resonance elastography
Glioblastoma (GBM) is the most common primary brain tumor. It is highly malignant and has a correspondingly poor prognosis. Diagnosis and monitoring are mainly accomplished with MRI, but remain challenging in some cases. Therefore, complementary methods for tumor detection and characterization would be beneficial. Using magnetic resonance elastography (MRE), we performed a longitudinal study of the biomechanical properties of intracranially implanted GBM in mice and compared the results to histopathology. The biomechanical parameters of viscoelastic modulus, shear wave speed and phase angle were significantly lower in tumo...
Source: NMR in Biomedicine - November 29, 2017 Category: Radiology Authors: Katharina Schregel, Navid Nazari, Michal O. Nowicki, Miklos Palotai, Sean E. Lawler, Ralph Sinkus, Paul E. Barbone, Samuel Patz Tags: SPECIAL ISSUE RESEARCH ARTICLE Source Type: research
