Abstract:
:The present work aims to show the applicability of an analytical model for the optimisation of the STEAM sequence timing parameters for lactate detection at ultra high-field. The effects of the chemical shift displacement artefact on the J-modulated signal for a weakly-coupled spin system were considered in the three applied directions of field gradients and the product operator formalism was used to obtain expressions for the signal modulation in each compartment of the excited volume. The validity of this model was demonstrated experimentally at 7 T in a phantom and acquisitions with optimised parameters were performed on a healthy volunteer. The spectra acquired with TE = 144 ms with the optimised mixing time and TE = 288 ms showed easily detectable lactate peaks in the normal human brain. Additionally, the acquisition with the longer TE resulted in a spectrum with less lipid/macromolecular contamination. The simulations shown here demonstrated that the proposed analytical model is suitable for correctly predicting the resulting lactate signal. With the optimised parameters, it was possible to use a simple sequence with sufficient signal-to-noise ratio to reliably distinguish lactate from overlapping resonances in a healthy brain.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Fernandes CC,Lanz B,Chen C,Morris PG,Salmon CGdoi
10.1002/nbm.4440subject
Has Abstractpub_date
2020-11-02 00:00:00pages
e4440eissn
0952-3480issn
1099-1492pub_type
杂志文章abstract::Electric properties tomography (EPT) derives the patient's electric properties, i.e. conductivity and permittivity, using standard magnetic resonance (MR) systems and standard MR sequences. Thus, EPT does not apply externally mounted electrodes, currents or radiofrequency (RF) probes, as is the case in competing techn...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.3729
更新日期:2017-08-01 00:00:00
abstract::The aim of this study was to measure choline/creatine (Ch/Cr) levels through (1)H-MRS and apparent diffusion coefficient (ADC) values through diffusion-weighted MRI, and to correlate these values with the prognostic parameters of head and neck squamous cell carcinoma (HNSCC). The institutional review board approved th...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3472
更新日期:2016-04-01 00:00:00
abstract::The purpose of this work was to assess the reproducibility of percentage of ventilated lung volume (PV) measured from hyperpolarized (HP) (3)He and (1)H anatomical images acquired in the same breath-hold when compared with PV measured from (3)He and (1)H images from separate breath-holds. Volumetric (3)He ventilation ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3187
更新日期:2014-12-01 00:00:00
abstract::The purpose of the present study was to characterize the metabolic profile of the visual cortex in streptozotocin-induced Type 1 diabetic rats by means of in vivo proton MRS. Several metabolite concentration ratios in the visual cortex were calculated. In addition, postmortem histologic analyses for retinal ganglion c...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3783
更新日期:2017-11-01 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::Chemical exchange saturation transfer (CEST) can offer information about protons associated with mobile proteins through the amide proton transfer (APT) effect, which has been shown to discriminate tumor from healthy tissue and, more recently, has been suggested as a prognosticator of response to therapy. Despite this...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2947
更新日期:2013-10-01 00:00:00
abstract::Manganese ions (Mn(2+) ) enter viable myocardial cells via voltage-gated calcium channels. Because of its shortening of T(1) and its relatively long half-life in cells, Mn(2+) can serve as an intracellular molecular contrast agent to study indirect calcium influx into the myocardium. One major concern in using Mn(2+) ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1554
更新日期:2011-01-01 00:00:00
abstract::Cerebrovascular reactivity (CVR) can give insight into the cerebrovascular function. CVR can be estimated by measuring a blood-oxygen-level-dependent (BOLD) response combined with breath-holding (BH). The reproducibility of this technique has been addressed and existing studies have focused on short-term reproducibili...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4195
更新日期:2020-03-01 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::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::This paper describes the use of off-resonance saturation to further manipulate the blood oxygenation level dependent (BOLD) contrast of fMRI. A customized narrow bandwidth radiofrequency pulse, applied with a range of frequency offsets prior to selection of each slice, was designed and incorporated into a gradient ech...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(sici)1099-1492(199706/08)10:4/5<208::aid-
更新日期:1997-06-01 00:00:00
abstract::The aim of this study is to fabricate and test a novel flexible flat cable antenna (FFCA) for MRI of the knee at different flexion angles. The FFCA was made of a flat cable, a tuning/matching circuit and a signal transmission line. To test its feasibility and validity, in vitro and in vivo experiments were carried out...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3264
更新日期:2015-04-01 00:00:00
abstract::Chronic pain is a major problem for the individual and for society. Despite a range of drugs being available to treat chronic pain, only inadequate pain relief can be achieved for many patients. There is therefore a need for the development of new analgesic compounds. The assessment of pain depends to date entirely on...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1076
更新日期:2006-10-01 00:00:00
abstract::Changes in physiological parameters such as cerebral blood flow, cerebral blood volume, oxygen extraction, and the size and distribution of cerebral blood vessels, result in changes in the local concentration of deoxyhaemoglobin ([dHb]). The purpose of this study was to quantitatively investigate the dependence of the...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(sici)1099-1492(199810)11:6<281::aid-nbm52
更新日期:1998-10-01 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::An indirect method for in vivo T2 mapping of 13 C-labeled metabolites using T2 and T2 * information of water protons obtained a priori is proposed. The T2 values of 13 C metabolites are inferred using the relationship to T2 ' of coexisting 1 H and the T2 * of 13 C metabolites, which is measured using routine hyperpola...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3690
更新日期:2017-05-01 00:00:00
abstract::The purpose of this study was to investigate the feasibility of interventional MRI-guided local agent delivery into pig common bile duct (CBD) walls using a newly designed MR-compatible, needle-integrated balloon catheter system. We first designed a needle-integrated balloon catheter system that comprised of a 22 G MR...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3308
更新日期:2015-06-01 00:00:00
abstract::Elevated brain myo-inositol (m-Ins) concentration (a putative marker of neuroinflammation) has been reported in patients suffering from type 2 diabetes mellitus (T2DM). Obesity alone and T2DM have been found to be associated with a lower concentration of N-acetyloaspartate and N-acetylaspartylglutamate (tNAA, a marker...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3957
更新日期:2018-09-01 00:00:00
abstract::Following the development of parallel imaging, parallel transmission describes the use of multiple RF transmit coils. Parallel transmission can be applied to improve RF excitation, in particular, multidimensional, spatially selective RF excitation. For instance, parallel transmission is able to shorten spatially selec...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1049
更新日期:2006-05-01 00:00:00
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 microstru...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3085
更新日期:2014-05-01 00:00:00
abstract::Quantitative analysis of extracts from two Ehrlich ascites tumour cell lines (Lettre cells) by 19F NMR in vitro demonstrated that one Lettre cell line (designated LLM) metabolized 30-50% less 5-fluorouracil to 5-fluoronucleotides when compared to the other cell line (designated LHM). HPLC analysis of these cellular ex...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940040605
更新日期:1991-12-01 00:00:00
abstract::T1ρ relaxation imaging is a quantitative imaging technique that has been used to assess cartilage integrity, liver fibrosis, tumors, cardiac infarction, and Alzheimer's disease. T1 , T2 , and T1ρ relaxation time constants have each demonstrated different degrees of sensitivity to several markers of fibrosis and inflam...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4284
更新日期:2020-05-01 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::An effective method for in vivo detection of early therapeutic response of patients with non-Hodgkin's lymphoma would enable personalized clinical management of cancer therapy and facilitate the design of optimal treatment regimens. This study evaluates the feasibility of T(2)-weighted MRI (T2WI) and diffusion-weighte...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1261
更新日期:2008-11-01 00:00:00
abstract::Diffusion tensor imaging (DTI) provides an indirect measure of tissue structure on a microscopic scale. To date, DTI is the only imaging method that provides such information in vivo, and has proven to be a valuable tool in both research and clinical settings. In this study, we investigated the relationship between wh...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1810
更新日期:2012-07-01 00:00:00
abstract::Acute kidney injury (AKI) in mice caused by sustained ischemia followed by reperfusion is associated with acute tubular necrosis and renal dysfunctional blood flow. Although the principal role of the kidney is the maintenance of acid-base balance, current imaging approaches are unable to assess this important paramete...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3720
更新日期:2017-07-01 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
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::Perfusion is an important biomarker of tissue function and has been associated with tumor pathophysiology such as angiogenesis and hypoxia. Arterial spin labeling (ASL) MRI allows noninvasive and quantitative imaging of perfusion; however, the application in mouse xenograft tumor models has been challenging due to the...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3330
更新日期:2015-08-01 00:00:00
abstract::The purpose of this paper is to facilitate the comparison of magnetic resonance (MR) spectra acquired from unknown brain lesions with published spectra in order to help identify unknown lesions in clinical settings. The paper includes lists of references for published MR spectra of various brain diseases, including py...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1039
更新日期:2006-06-01 00:00:00