Abstract:
:The dependence of apparent diffusion coefficients (ADCs) of molecules in biological tissues on an acquisition-specific timescale is a powerful mechanism for studying tissue microstructure. Unlike water, metabolites are confined mainly to intracellular compartments, thus providing higher specificity to tissue microstructure. Compartment-specific structural and chemical properties may also affect molecule transverse relaxation times (T₂). Here, we investigated the correlation between diffusion and relaxation for N-acetylaspartate, creatine and choline compounds in human brain white matter in vivo at 7 T, and compared them with those of water under the same experimental conditions. Data were acquired in a volume of interest in parietal white matter at two different diffusion times, Δ = 44 and 246 ms, using a matrix of three echo times (T(E)) and five diffusion weighting values (up to 4575 s/mm²). Significant differences in the dependence of the ADCs on T(E) were found between water and metabolites, as well as among the different metabolites. A significant decrease in water ADC as a function of TE was observed only at the longest diffusion time (p < 0.001), supporting the hypothesis that at least part of the restricted water pool can be associated with longer T₂, as suggested by previous studies in vitro. Metabolite data showed an increase of creatine (p < 0.05) and N-acetylaspartate (p < 0.05) ADCs with TE at Δ = 44 ms, and a decrease of creatine (p < 0.05) and N-acetylaspartate (p = 0.1) ADCs with TE at Δ = 246 ms. No dependence of choline ADC on TE was observed. The metabolite results suggest that diffusion and relaxation properties are dictated not only by metabolite distribution in different cell types, but also by other mechanisms, such as interactions with membranes, exchange between "free" and "bound" states or interactions with microsusceptibility gradients.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Branzoli F,Ercan E,Webb A,Ronen Idoi
10.1002/nbm.3085subject
Has Abstractpub_date
2014-05-01 00:00:00pages
495-506issue
5eissn
0952-3480issn
1099-1492journal_volume
27pub_type
杂志文章abstract::Transceiver surface coil arrays improve transmit performance (B1/√kW) and B1 homogeneity for head imaging up to 9.4 T. To further improve reception performance and parallel imaging, the number of array elements must be increased with a corresponding decrease in their size. With a large number of small interacting ante...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2989
更新日期:2013-11-01 00:00:00
abstract::Wilms' tumours (WTs) are large heterogeneous tumours, which typically consist of a mixture of histological cell types, together with regions of chemotherapy-induced regressive change and necrosis. The predominant cell type in a WT is assessed histologically following nephrectomy, and used to assess the tumour subtype ...
journal_title:NMR in biomedicine
pub_type: 临床试验,杂志文章
doi:10.1002/nbm.3337
更新日期:2015-08-01 00:00:00
abstract::Biomarkers of early response to treatment have the potential to improve cancer therapy by allowing treatment to be tailored to the individual. Alterations in lipids detected by in vivo MRS have been suggested as noninvasive biomarkers of cell stress and early indicators of cell death. An improved understanding of the ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2796
更新日期:2012-11-01 00:00:00
abstract::Management of brain tumours in children would benefit from improved non-invasive diagnosis, characterisation and prognostic biomarkers. Metabolite profiles derived from in-vivo MRS have been shown to provide such information. Studies indicate that using optimum a priori information on metabolite contents in the constr...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1432
更新日期:2010-01-01 00:00:00
abstract::This review highlights various magnetic resonance image (MRI) segmentation algorithms that employ pattern recognition. The procedures are grouped into two categories: low- to intermediate-level, and high-level image processing. The former consists of grey level histogram analysis, texture definition, edge identificati...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/(sici)1099-1492(199806/08)11:4/5<157::aid-
更新日期:1998-06-01 00:00:00
abstract::Diffusion tensor imaging (DTI) has been employed for over 2 decades to noninvasively quantify central nervous system diseases/injuries. However, DTI is an inadequate simplification of diffusion modeling in the presence of coexisting inflammation, edema and crossing nerve fibers. We employed a tissue phantom using fixe...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4414
更新日期:2021-01-01 00:00:00
abstract::Acute hypoxia (transient cycles of hypoxia-reoxygenation) is known to occur in solid tumors and is generally believed to be caused by tumor blood flow instabilities. It was recently demonstrated that T2*-weighted (T2*w) gradient echo (GRE) MRI is a powerful non-invasive method for investigating periodic changes in tum...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1002
更新日期:2006-02-01 00:00:00
abstract::The progression of Parkinson's disease (PD) seems to vary according to the disease stage, which greatly influences the management of PD patients. However, the underlying mechanism of progression in PD remains unclear. This study was designed to explore the progressive pattern of iron accumulation at different stages i...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3489
更新日期:2017-04-01 00:00:00
abstract::More than 50% of cancers fail to respond to any individual treatment and tumour follow-up after treatment plays a major role in routine therapy planning and pharmacological research. Today, MRS is the only technological approach providing non-invasive access to tumour biochemistry. Ten years ago, expectations were rai...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940060602
更新日期:1993-11-01 00:00:00
abstract::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, su...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3877
更新日期:2018-03-01 00:00:00
abstract::The aim of this study was to evaluate the change of breast density in the normal breast of patients receiving neoadjuvant chemotherapy (NAC). Forty-four breast cancer patients were studied. MRI acquisition was performed before treatment (baseline), and 4 and 12 weeks after treatment. A computer-algorithm-based program...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3006
更新日期:2013-12-01 00:00:00
abstract::Cerebral edema is a major complication of acute liver failure but may also be seen in other forms of liver failure such as acute-on-chronic liver failure (ACLF) and chronic liver failure (CLF). ACLF develops in patients with previously well-compensated chronic liver disease following acute hepatitis A or E superimpose...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1249
更新日期:2008-08-01 00:00:00
abstract::Citicoline supplementation has been used to ameliorate memory disturbances in older people and those with Alzheimer's disease. This study used MRS to characterize the effects of citicoline on high-energy phosphate metabolites and constituents of membrane synthesis in the frontal lobe. Phosphorus ((31)P) metabolite dat...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1281
更新日期:2008-11-01 00:00:00
abstract::An MR thermometry method is proposed for measuring in vivo small temperature changes engendered by external RF heat sources. The method relies on reproducible and stable respiration and therefore currently applies to ventilated animals whose breathing is carefully controlled. It first consists in characterizing the st...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3232
更新日期:2015-01-01 00:00:00
abstract::To understand and predict the blood-oxygenation level-dependent (BOLD) fMRI signal, an accurate knowledge of the relationship between cerebral blood flow (DeltaCBF) and volume (DeltaCBV) changes is critical. Currently, this relationship is widely assumed to be characterized by Grubb's power-law, derived from primate d...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1411
更新日期:2009-12-01 00:00:00
abstract:INTRODUCTION:Sarcoidosis is a systemic granulomatous disease affecting in particular the respiratory tract. Cardiac magnetic resonance (CMR), including a measurement of T1 relaxation time, could potentially detect early stadia of sarcoidosis of the heart. The study aims to assess T1 mapping in the detection of early ca...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4388
更新日期:2020-11-01 00:00:00
abstract::We propose a very high-resolution, three-dimensional (3D) gradient-echo technique with a twofold parallel imaging acceleration using a specialized occipital receiver coil at 3 T to perform functional MRI (fMRI) of the visual cortex. This configuration makes it possible to acquire 3D fMRI data within a timescale compat...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1158
更新日期:2007-08-01 00:00:00
abstract::This review assesses the progress of NMR in the field of hemorheology, i.e., the assessment of the mechanical and physical characteristics of flowing blood. The review deals with the intrinsic rheological properties of the red cell and its constituents (membrane, cytoplasm), which are dominant in the microcirculation,...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940020102
更新日期:1989-06-01 00:00:00
abstract::We show how quantitative information about proton handling in human skeletal muscle in exercise and recovery can be obtained by 31P MRS and illustrate this with data from metabolic disorders. Proton production, proton efflux and passive buffering can be distinguished by comparing changes in [phosphocreatine] and pH at...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940060112
更新日期:1993-01-01 00:00:00
abstract::The potential for using pre-polarized liquids as contrast agents in vivo is investigated and the feasibility of the method demonstrated. In this study we show the enhancement obtained following intravenous delivery of pre-polarized saline into the antecubital vein of a volunteer. This form of contrast agent provides s...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(sici)1099-1492(199910)12:6<381::aid-nbm57
更新日期:1999-10-01 00:00:00
abstract::A study was undertaken to determine if the vascular characteristics measured by dynamic contrast-enhanced magnetic resonance imaging (primarily permeability surface area product and extracellular-extravascular tissue volume fraction) would be beneficial in explaining the inter-lesion metabolic heterogeneity displayed ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.675
更新日期:2000-12-01 00:00:00
abstract::Most ovarian tumors are cystic structures containing variable amounts of fluid. Several studies of ovarian cyst fluid focus on one specific metabolite using conventional assay systems. We examined the potential of (1)H-nuclear magnetic resonance spectroscopy in evaluation of the overall metabolic composition of cyst f...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/1099-1492(200008)13:5<297::aid-nbm648>3.0.
更新日期:2000-08-01 00:00:00
abstract::Aminoacylase 1 deficiency is a novel inborn error of metabolism. The clinical significance of the deficiency is under discussion, as well as the possible consequences of the defect for brain metabolism and function. This study includes the five originally published cases as well as three novel ones. NMR spectroscopy o...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1170
更新日期:2008-02-01 00:00:00
abstract::In this study, mapping of ultrashort T2 and T2* of acutely isolated porcine menisci at B0 = 9.4 T was investigated. Maps of T2 were measured from a slice through the pars intermedia with a spin echo-prepared two-dimensional ultrashort-TE T2 mapping technique published previously. T2* mapping was performed by two-dimen...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2931
更新日期:2013-09-01 00:00:00
abstract::In this study, metabolic changes in the 79A/C3H, ME7/VM, ME7/C3H, 87V/VM and 22A/SV scrapie mouse models were investigated during the clinical phase of the disease, using in vitro proton nuclear magnetic resonance spectroscopy. N-acetyl-aspartate was found to be significantly reduced in infected mice of the ME7/ C3H (...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(SICI)1099-1492(199612)9:8<359::AID-NBM428
更新日期:1996-12-01 00:00:00
abstract::MRS provides a valuable tool for the non-invasive detection of brain γ-aminobutyric acid (GABA) in vivo. GABAergic dysfunction has been observed in the aging cerebellum. The study of cerebellar GABA changes is of considerable interest in understanding certain age-related motor disorders. However, little is known about...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3381
更新日期:2015-10-01 00:00:00
abstract::A simple technique permitting long term 31P magnetic resonance spectroscopy of cultured mammalian cells is described. Cells are encapsulated in calcium alginate gels and perfused with a new phosphate-fre medium designed for maintenance of high cell viability. Intracellular pH and beta-NTP/Pi ratios, studied in three c...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940030104
更新日期:1990-02-01 00:00:00
abstract::Encoding of spatial information in magnetic resonance imaging is conventionally accomplished by using magnetic field gradients. During gradient encoding, the position in k-space is determined by a time-integral of the gradient field, resulting in a limitation in imaging speed due to either gradient power or secondary ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1399
更新日期:2009-11-01 00:00:00
abstract::The purpose of this work was to harmonize data acquisition and post-processing of single voxel proton MRS ((1) H-MRS) at 7 T, and to determine metabolite concentrations and the accuracy and reproducibility of metabolite levels in the adult human brain. This study was performed in compliance with local institutional hu...
journal_title:NMR in biomedicine
pub_type: 杂志文章,多中心研究
doi:10.1002/nbm.3252
更新日期:2015-03-01 00:00:00
abstract::The sodium-calcium exchanger (NCX) is one of the transporters contributing to the control of intracellular calcium (Ca(2+)) concentration by normally mediating net Ca(2+) efflux. However, the reverse mode of the NCX can cause intracellular Ca(2+) concentration overload, which exacerbates the myocardial tissue injury r...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1414
更新日期:2009-10-01 00:00:00