Abstract:
:The accuracy and precision of the quantification of metabolite concentrations in in vivo (1) H NMR spectroscopy are affected by linewidth and signal-to-noise ratio (SNR). To study the effect of both factors in in vivo (1) H NMR spectra acquired at ultrahigh field, a reference spectrum was generated by summing nine in vivo (1) H NMR spectra obtained in rat brain with a STEAM sequence at 16.4 T. By progressive deterioration of linewidth and SNR, 6400 single spectra were generated. In an accuracy study, the variation in the mean concentrations of five metabolites was mainly dependent on SNR, whereas 11 metabolites were predominantly susceptible to the linewidth. However, the standard deviations of the concentrations obtained were dependent almost exclusively on the SNR. An insignificant correlation was found between most of the heavily overlapping metabolite peaks, indicating independent and reliable quantification. Two different approaches for the consideration of macromolecular signals were evaluated. The use of prior knowledge derived by parameterization of a metabolite-nulled spectrum demonstrated improved fitting quality, with reduced Cramér-Rao lower bounds, compared to the calculation of a regularized spline baseline.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Hong ST,Pohmann Rdoi
10.1002/nbm.2821subject
Has Abstractpub_date
2013-01-01 00:00:00pages
74-82issue
1eissn
0952-3480issn
1099-1492journal_volume
26pub_type
杂志文章abstract::We describe the optimal high-level postprocessing of single-voxel (1)H magnetic resonance spectra and assess the benefits and limitations of automated methods as diagnostic aids in the detection of recurrent brain tumor. In a previous clinical study, 90 long-echo-time single-voxel spectra were obtained from 52 patient...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1041
更新日期:2006-08-01 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::In many small animals there are distinct differences in fiber-type composition among limb muscles, and these differences typically correspond to marked disparities in the oxidative capacities. However, whether there are similar differences in the oxidative capacity among leg muscles in humans is less clear. The purpos...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1413
更新日期:2009-12-01 00:00:00
abstract::We have developed a reliable, reproducible model of hypoxia in the gerbil. 1H and 31P NMR spectroscopy demonstrates that cerebral energy metabolism is very resistant to hypoxia. Cerebral blood flow (measured by hydrogen clearance) began to increase when the arterial oxygen tension (paO2) was reduced to 40-50 mm Hg, an...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940050109
更新日期:1992-01-01 00:00:00
abstract::This paper compares two spectral processing methods for obtaining quantitative measures from in vivo prostate spectra, evaluates their effectiveness, and discusses the necessary modifications for accurate results. A frequency domain analysis (FDA) method based on peak integration was compared with a time domain fittin...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1008
更新日期:2006-04-01 00:00:00
abstract::The purpose of this work was to carry out diffusion tensor imaging (DTI) at multiple diffusion times Td in skeletal muscle in normal subjects and chronic exertional compartment syndrome (CECS) patients and analyze the data with the random permeable barrier model (RPBM) for biophysical specificity. Using an institution...
journal_title:NMR in biomedicine
pub_type: 临床试验,杂志文章
doi:10.1002/nbm.3087
更新日期:2014-05-01 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::Phosphorus MRSI (31 P-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunte...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3662
更新日期:2016-12-01 00:00:00
abstract::The aim of this study was to investigate physiological variations of the water T2 relaxation time in vertebral bone marrow with respect to age, body mass index (BMI), sex and proton density fat fraction (PDFF) based on single-voxel magnetic resonance spectroscopy (MRS) at 3 T. Multi-TE single-voxel STEAM MRS data of a...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4439
更新日期:2020-11-17 00:00:00
abstract:PURPOSE:To investigate the feasibility of using multiple flip angles in dynamic contrast enhanced (DCE) MRI to reduce the uncertainty in estimation of intracellular water lifetime (τi ). METHODS:Numerical simulation studies were conducted to assess the uncertainty in estimation of τi using dynamic contrast enhanced MR...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4135
更新日期:2019-11-01 00:00:00
abstract::We introduce a new protocol to obtain very high-frame-rate cinematographic (Cine) MRI movies of the beating mouse heart within a reasonable measurement time. The method is based on a self-gated accelerated fast low-angle shot (FLASH) acquisition and compressed sensing reconstruction. Key to our approach is that we exp...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2883
更新日期:2013-04-01 00:00:00
abstract::We review several methods that have been developed to infer microstructural and physiological information about isotropic and anisotropic tissues from diffusion weighted images (DWIs). These include Diffusion Imaging (DI), Diffusion Tensor Imaging (DTI), isotropically weighted imaging, and q-space imaging. Just as DI ...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940080707
更新日期:1995-11-01 00:00:00
abstract::In this work we introduce the concept of correlation chemical shift imaging (CCSI). Novel CCSI pulse sequences are demonstrated on clinical scanners for two-dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY) imaging experiments. To date there has been limited progress reported towar...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1730
更新日期:2012-02-01 00:00:00
abstract::Results are presented from an in vivo study of human skin in which a zig-zag surface coil together with a three-pulse Fourier Series Window (FSW) protocol have been used to obtain minimally contaminated 31P skin spectra of the posterior calf. Phantom experiments indicate that while the fall-off in the B1 field profile...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(SICI)1099-1492(199608)9:5<195::AID-NBM416
更新日期:1996-08-01 00:00:00
abstract::The cerebral blood volume (CBV) is a crucial physiological indicator of tissue viability and vascular reactivity. Thus, noninvasive CBV mapping has been of great interest. For this, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, including monocrystalline iron oxide nanoparticles, can be used as long-ha...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.2885
更新日期:2013-08-01 00:00:00
abstract::Two FDA-approved agents, ferumoxides (Feridex), a suspension of superparamagnetic iron oxide (SPIO) nanoparticles and protamine sulfate, a drug used to reverse heparin anticoagulation, can be complexed and used to label cells magnetically ex vivo. Labeling stem cells with ferumoxides-protamine sulfate (FePro) complexe...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.991
更新日期:2005-12-01 00:00:00
abstract::Modified gradient-echo MR techniques were applied to study the effects of inflow on functional brain imaging studies using visual and motor cortex stimulation. The results demonstrate that the large signal changes, seen in previously reported gradient-echo studies at 1.5-2.0 T, are dominated by direct inflow effects, ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940070113
更新日期:1994-03-01 00:00:00
abstract::Standard functional MRI (fMRI), which includes resting-state or paradigm-driven designs, is widely used in studies of brain function, aging, and disease. These fMRI studies typically use two-dimensional gradient echo-planar imaging, which inherently contains phase data that enables quantitative susceptibility mapping ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3619
更新日期:2017-04-01 00:00:00
abstract::Proton magnetic resonance spectroscopy at 1.9 T was used to quantify dolichols, cholesterols, choline-containing phospholipids and double bonds in unsaturated acyl chains in lipid extracts of four types of thyroid tissue [normal (n = 27), papillary cancer (n = 15), adenoma (n = 13) and Basedow disease (n = 6)]. In nor...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/1099-1492(200011)13:7<377::aid-nbm658>3.0.
更新日期:2000-11-01 00:00:00
abstract::The management and treatment of high-grade glioblastoma multiforme (GBM) and solitary metastasis (MET) are very different and influence the prognosis and subsequent clinical outcomes. In the case of a solitary MET, diagnosis using conventional radiology can be equivocal. Currently, a definitive diagnosis is based on h...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3163
更新日期:2014-09-01 00:00:00
abstract::Early imaging or blood biomarkers of tumor response is needed to customize anti-tumor therapy on an individual basis. This study evaluates the sensitivity and relevance of five potential MRI biomarkers. Sixty nude rats were implanted with human glioma cells (U-87 MG) and randomized into three groups: one group receive...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1611
更新日期:2011-06-01 00:00:00
abstract::The temporary or permanent storage of human bodies in freezers following a homicide is a documented method for criminal disposal of human corpses. In these cases, the detection of characteristics which indicate that a thawed cadaver or body part was previously frozen provides crucial information for forensic casework....
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4220
更新日期:2020-02-01 00:00:00
abstract::This paper describes the development of a novel technique for functional MRI of the human brain at 0.135 microL resolution for a whole brain section. In comparison with conventional studies at 3 mm isotropic resolution or 27 microL voxel size, the method yields an improvement by a factor of 200. To achieve optimum ima...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.998
更新日期:2005-12-01 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::The aim of this study was to acquire the transient MRI signal of hyperpolarized tracers and their metabolites efficiently, for which specialized imaging sequences are required. In this work, a multi-echo balanced steady-state free precession (me-bSSFP) sequence with Iterative Decomposition with Echo Asymmetry and Leas...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4291
更新日期:2020-06-01 00:00:00
abstract::Vessel size index (VSI), a parameter related to the distribution of vessel diameters, may be estimated using two MRI approaches: (i) dynamic susceptibility contrast (DSC) MRI following the injection of a bolus of Gd-chelate. This technique is routinely applied in the clinic to assess intracranial tissue perfusion in p...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1734
更新日期:2012-02-01 00:00:00
abstract::The development and implementation of novel MRI pulse sequences remains challenging and laborious. Gradient waveforms are typically designed using a combination of analytical and ad hoc methods to construct each gradient waveform axis independently. This strategy makes coding the pulse sequence complicated, in additio...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4308
更新日期:2020-12-01 00:00:00
abstract::The myeloproliferative leukemic virus (MPLV) induces within 2-3 weeks a massive infiltration of the adult mouse liver by hematopoietic leukemic cells. Since the metabolism of the infiltrated organ might be correlated with an interaction of two cell populations, it was decided to study the isolated hematopoietic cells ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940020106
更新日期:1989-06-01 00:00:00
abstract::Cross-talk between adipose tissue and liver is disturbed in the metabolic syndrome. Moreover, the relative fatty acid composition of adipose and liver fat is poorly characterized. Long-TE (1)H MRS can determine the unsaturation and polyunsaturation of adipose tissue. The aim of this study was to use long-TE (1)H MRS t...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1580
更新日期:2011-04-01 00:00:00
abstract::Spontaneous fluctuations in the blood oxygenation level-dependent (BOLD) MRI signal during the resting state are increasingly being studied in healthy and diseased brain in humans and animal models. Yet, the relationship between functional brain status and the characteristics of spontaneous BOLD fluctuations remains p...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1556
更新日期:2011-01-01 00:00:00