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NMR in Biomedicine

Shannon B Donnola, Connie M Piccone, Lan Lu, Joshua Batesole, Jane Little, Katherine M Dell, Chris A Flask
Chronic kidney disease (CKD) occurs in over one-third of patients with sickle cell disease (SCD) and can progress to end-stage renal disease. Unfortunately, current clinical assessments of kidney function are insensitive to early-stage CKD. Previous studies have shown that diffusion magnetic resonance imaging (MRI) can sensitively detect regional renal microstructural changes associated with early-stage CKD. However, previous MRI studies in patients with SCD have been largely limited to the detection of renal iron deposition assessed by T2 * relaxometry...
January 19, 2018: NMR in Biomedicine
Mara Cercignani, Claudia Gandini Wheeler-Kingshott
Diffusion imaging has been instrumental in understanding damage to the central nervous system as a result of its sensitivity to microstructural changes. Clinical applications of diffusion imaging have grown exponentially over the past couple of decades in many neurological and neurodegenerative diseases, such as multiple sclerosis (MS). For several reasons, MS has been extensively researched using advanced neuroimaging techniques, which makes it an 'example disease' to illustrate the potential of diffusion imaging for clinical applications...
January 19, 2018: NMR in Biomedicine
Daniel J Huereca, Konstandinos A Bakoulas, Farhad Ghoddoussi, Bruce A Berkowitz, Avril Genene Holt, Patrick J Mueller
Spinally projecting neurons in the rostral ventrolateral medulla (RVLM) are believed to contribute to pathophysiological alterations in sympathetic nerve activity and the development of cardiovascular disease. The ability to identify changes in the activity of RVLM neurons in conscious animals and humans, especially longitudinally, would represent a clinically important advancement in our understanding of the contribution of the RVLM to cardiovascular disease. To this end, we describe the initial development of manganese-enhanced magnetic resonance imaging (MEMRI) for the rat RVLM...
January 12, 2018: NMR in Biomedicine
Teng Ma, Shaolin Yang, Haiyan Jing, Lin Cong, Zhixin Cao, Zhiling Liu, Zhaoqin Huang
Prostate cancer (PCa) is the second most common cancer in men. The Gleason score (GS) and biomarkers play important roles in the diagnosis and treatment of patients with PCa. The purpose of this study was to investigate the relationship between the apparent diffusion coefficient (ADC) and the molecular markers Ki-67, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in PCa. Thirty-nine patients with 39 lesions, who had been diagnosed with PCa, were enrolled in this study. All patients underwent diffusion-weighted magnetic resonance imaging (DW-MRI) (b = 800 s/mm2 )...
January 9, 2018: NMR in Biomedicine
Katharina Paul, Till Huelnhagen, Eva Oberacker, Daniel Wenz, André Kuehne, Helmar Waiczies, Sebastian Schmitter, Oliver Stachs, Thoralf Niendorf
This study shows that diffusion-weighted rapid acquisition with relaxation enhancement-echo planar imaging (RARE-EPI) has the capability to acquire distortion-free images of the eye and orbit with ample diffusion contrast. The results underpin the challenges of ocular imaging at 3.0 T and 7.0 T for EPI and demonstrate that these issues can be offset using accelerated RARE-based approaches. This benefit can be exploited for the assessment of spatial arrangements of the eye segments and their masses with the goal to provide guidance in the diagnostic assessment and treatment of ophthalmological diseases...
January 9, 2018: NMR in Biomedicine
Paola Porcari, Matt G Hall, Chris A Clark, Elizabeth Greally, Volker Straub, Andrew M Blamire
The investigation of age-related changes in muscle microstructure between developmental and healthy adult mice may help us to understand the clinical features of early-onset muscle diseases, such as Duchenne muscular dystrophy. We investigated the evolution of mouse hind-limb muscle microstructure using diffusion imaging of in vivo and in vitro samples from both actively growing and mature mice. Mean apparent diffusion coefficients (ADCs) of the gastrocnemius and tibialis anterior muscles were determined as a function of diffusion time (Δ), age (7...
January 9, 2018: NMR in Biomedicine
Isaac M Adanyeguh, Marie-Lorraine Monin, Daisy Rinaldi, Léorah Freeman, Alexandra Durr, Stéphane Lehéricy, Pierre-Gilles Henry, Fanny Mochel
The striatum is a well-known region affected in Huntington disease (HD). However, other regions, including the visual cortex, are implicated. We have identified previously an abnormal energy response in the visual cortex of patients at an early stage of HD using 31 P magnetic resonance spectroscopy (31 P MRS). We therefore sought to further characterize these metabolic alterations with 1 H MRS using a well-validated semi-localized by adiabatic selective refocusing (semi-LASER) sequence that allows the measurement of an expanded number of neurometabolites...
January 9, 2018: NMR in Biomedicine
Md Nasir Uddin, Teresa D Figley, Ruth Ann Marrie, Chase R Figley
Given the growing popularity of T1 -weighted/T2 -weighted (T1 w/T2 w) ratio measurements, the objective of the current study was to evaluate the concordance between T1 w/T2 w ratios obtained using conventional fast spin echo (FSE) versus combined gradient and spin echo (GRASE) sequences for T2 w image acquisition, and to compare the resulting T1 w/T2 w ratios with histologically validated myelin water fraction (MWF) measurements in several subcortical brain structures. In order to compare these measurements across a relatively wide range of myelin concentrations, whole-brain T1 w magnetization prepared rapid acquisition gradient echo (MPRAGE), T2 w FSE and three-dimensional multi-echo GRASE data were acquired from 10 participants with multiple sclerosis at 3 T...
January 9, 2018: NMR in Biomedicine
Yi-Jui Liu, Yi-Hsiung Lee, Hing-Chiu Chang, Hui-Chu Chiu, Ta-Wei Chiu, Kang Hsu, Cheng-Ming Pen, Hsian-He Hsu, Chun-Jung Juan
The aim of this study was to investigate proton changes of the parotid gland after gustatory stimulation by semi-quantitative parameters and an empirical mathematical model (EMM) using high-temporal-resolution, double-echo, echo-planar imaging (EPI). Approved by a local institutional review board, this study examined 20 parotid glands from 10 healthy volunteers (male:female = 6: 4; age ± standard deviation =35.1 ± 14.1 years) with written informed consent obtained. All participants underwent 1.5-T, double-echo EPI with gustatory stimulation...
January 8, 2018: NMR in Biomedicine
Dmitry Shishmarev, Alan J Wright, Tiago B Rodrigues, Giuseppe Pileio, Gabriele Stevanato, Kevin M Brindle, Philip W Kuchel
Fumarate is an important probe of metabolism in hyperpolarized magnetic resonance imaging and spectroscopy. It is used to detect the release of fumarase in cancer tissues, which is associated with necrosis and drug treatment. Nevertheless, there are limited reports describing the detailed kinetic studies of this enzyme in various cells and tissues. Thus, we aimed to evaluate the sub-minute kinetics of human red blood cell fumarase using nuclear magnetic resonance (NMR) spectroscopy, and to provide a quantitative description of the enzyme that is relevant to the use of fumarate as a probe of cell rupture...
January 8, 2018: NMR in Biomedicine
Adam Berrington, Natalie L Voets, Sarah J Larkin, Nick de Pennington, James Mccullagh, Richard Stacey, Christopher J Schofield, Peter Jezzard, Stuart Clare, Tom Cadoux-Hudson, Puneet Plaha, Olaf Ansorge, Uzay E Emir
Abnormally high levels of the 'oncometabolite' 2-hydroxyglutarate (2-HG) occur in many grade II and III gliomas, and correlate with mutations in the genes of isocitrate dehydrogenase (IDH) isoforms. In vivo measurement of 2-HG in patients, using magnetic resonance spectroscopy (MRS), has largely been carried out at 3 T, yet signal overlap continues to pose a challenge for 2-HG detection. To combat this, several groups have proposed MRS methods at ultra-high field (≥7 T) where theoretical increases in signal-to-noise ratio and spectral resolution could improve 2-HG detection...
January 5, 2018: NMR in Biomedicine
Yoshiyuki Hirano, Cecil C Yen, Junjie V Liu, Julie B Mackel, Hellmut Merkle, George C Nascimento, Bojana Stefanovic, Afonso C Silva
Understanding the spatiotemporal features of the hemodynamic response function (HRF) to brain stimulation is essential for the correct application of neuroimaging methods to study brain function. Here, we investigated the spatiotemporal evolution of the blood oxygen level-dependent (BOLD) and cerebral blood volume (CBV) HRF in conscious, awake marmosets (Callithrix jacchus), a New World non-human primate with a lissencephalic brain and with growing use in biomedical research. The marmosets were acclimatized to head fixation and placed in a 7-T magnetic resonance imaging (MRI) scanner...
December 29, 2017: NMR in Biomedicine
Mingyan Li, Ewald Weber, Jin Jin, Thimo Hugger, Yasvir Tesiram, Peter Ullmann, Simon Stark, Miguel Fuentes, Sven Junge, Feng Liu, Stuart Crozier
The rotating radiofrequency coil (RRFC) has been developed recently as an alternative approach to multi-channel phased-array coils. The single-element RRFC avoids inter-channel coupling and allows a larger coil element with better B1 field penetration when compared with an array counterpart. However, dedicated image reconstruction algorithms require accurate estimation of temporally varying coil sensitivities to remove artefacts caused by coil rotation. Various methods have been developed to estimate unknown sensitivity profiles from a few experimentally measured sensitivity maps, but these methods become problematic when the RRFC is used as a transceiver coil...
December 27, 2017: NMR in Biomedicine
Karthik Lakshmanan, Ryan Brown, Guillaume Madelin, Yongxian Qian, Fernando Boada, Graham C Wiggins
The purpose of this work is to illustrate a new coil decoupling strategy and its application to a transmit/receive sodium/proton phased array for magnetic resonance imaging (MRI) of the human brain. We implemented an array of eight triangular coils that encircled the head. The ensemble of coils was arranged to form a modified degenerate mode birdcage whose eight shared rungs were offset from the z-axis at interleaved angles of ±30°. This key geometric modification resulted in triangular elements whose vertices were shared between next-nearest neighbors, which provided a convenient location for counter-wound decoupling inductors, whilst nearest-neighbor decoupling was addressed with shared capacitors along the rungs...
December 27, 2017: NMR in Biomedicine
Laura Ziser, Naja Meyer-Schell, Nyoman D Kurniawan, Robert Sullivan, David Reutens, Min Chen, Viktor Vegh
The availability of high-field-strength magnetic resonance imaging (MRI) systems has brought about the development of techniques that aim to map myelination via the exploitation of various contrast mechanisms. Myelin mapping techniques have the potential to provide tools for the diagnosis and treatment of diseases, such as multiple sclerosis. In this study, we evaluated the sensitivity of T2 *, frequency shift and susceptibility measures to myelin levels in a cuprizone mouse model of demyelination. The model was supplemented with two different dosages of fingolimod, a drug known to positively affect demyelination...
December 20, 2017: NMR in Biomedicine
Piotr Kozlowski, Silvia D Chang, Edward C Jones, S Larry Goldenberg
The purpose of this study was to evaluate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in the detection of dominant prostate tumors with multi-parametric MRI of the whole gland. Combined diffusion tensor imaging (DTI) and DCE MRI from 16 patients with biopsy-proven prostate cancer and no previous treatment were acquired with a 3.0-T MRI scanner prior to radical prostatectomy, and used to identify dominant tumors. MRI results were validated by whole-mount histology. Paired t-test and Wilcoxon test, logistic generalized linear mixed effect models and receiver operating characteristic (ROC) analyses were used for the estimation of the statistical significance of the results...
December 20, 2017: NMR in Biomedicine
Małgorzata Marjańska, Dinesh K Deelchand, James S Hodges, J Riley McCarten, Laura S Hemmy, Andrea Grant, Melissa Terpstra
The resonances originating from proteins underlie those of metabolites in brain 1 H nuclear magnetic resonance (NMR) spectra. These resonances have different physical properties from those of metabolites, such as shorter T1 and T2 relaxation time constants. The age dependence of the macromolecular pattern and content in the human brain was investigated with a focus on adults over 66 years of age using ultrahigh-field in vivo magnetic resonance spectroscopy. Eighteen young and 23 cognitively normal older adults were studied at 7 T...
December 20, 2017: NMR in Biomedicine
Ana Francisca Soares, Hongxia Lei
This study demonstrates the suitability of magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) for the imaging of congenital portosystemic shunts (PSS) in mice, a vascular abnormality in which mesenteric blood bypasses the liver and is instead drained directly to the systemic circulation. The non-invasive diagnosis performed in tandem with other experimental assessments permits further characterization of liver, whole-body and brain metabolic defects associated with PSS. Magnetic resonance measurements were performed in a 26-cm, horizontal-bore, 14...
December 20, 2017: NMR in Biomedicine
Byungjai Kim, Hyunseok Seo, Dongchan Kim, HyunWook Park
A simultaneous acquisition technique of image and navigator signals (simultaneously acquired navigator, SIMNAV) is proposed for cardiac magnetic resonance imaging (CMRI) in Cartesian coordinates. To simultaneously acquire both image and navigator signals, a conventional balanced steady-state free precession (bSSFP) pulse sequence is modified by adding a radiofrequency (RF) pulse, which excites a supplementary slice for the navigator signal. Alternating phases of the RF pulses make it easy to separate the simultaneously acquired magnetic resonance data into image and navigator signals...
December 20, 2017: NMR in Biomedicine
Patrick Wespi, Jonas Steinhauser, Grzegorz Kwiatkowski, Sebastian Kozerke
No abstract text is available yet for this article.
December 15, 2017: NMR in Biomedicine
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