Abstract:
:NMR relaxometry can provide information about the relaxation of the magnetization in different tissues, increasing our understanding of molecular dynamics and biochemical composition in biological systems. In general, tissues have complex and heterogeneous structures composed of multiple pools. As a result, bulk magnetization returns to its original state with different relaxation times, in a multicomponent relaxation. Recovering the distribution of relaxation times in each voxel is a difficult inverse problem; it is usually unstable and requires long acquisition time, especially on clinical scanners. MRI can also be viewed as an inverse problem, especially when compressed sensing (CS) is used. The solution of these two inverse problems, CS and relaxometry, can be obtained very efficiently in a synergistically combined manner, leading to a more stable multicomponent relaxometry obtained with short scan times. In this paper, we will discuss the details of this technique from the viewpoint of inverse problems.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Zibetti MVW,Helou ES,Sharafi A,Regatte RRdoi
10.1002/nbm.4318subject
Has Abstractpub_date
2020-12-01 00:00:00pages
e4318issue
12eissn
0952-3480issn
1099-1492journal_volume
33pub_type
杂志文章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::It is generally accepted that tumour microcirculation, blood flow, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status--factors which are usually closely linked and which define the so-called metabolic microenvironment--can markedly influence the therapeutic response of malignant tumours to...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940050505
更新日期:1992-09-01 00:00:00
abstract::MRI detects changes in blood-oxygenation-level dependent (BOLD) contrast in tumors caused by tumor oxygenating agents. These changes can be used to guide the design of improved tumor oxygenating treatments (TOXs). The conventional approach to detection of BOLD effects assumes that the water resonance is a single, homo...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.728
更新日期:2002-02-01 00:00:00
abstract::Spatiotemporally structured noise, such as physiological noise, is a potential source of artifacts in functional magnetic resonance imaging (fMRI) and is the main limiting factor for the detection of small blood oxygen level-dependent (BOLD) signal variations. fMRI was employed to detect low-frequency BOLD signal fluc...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.987
更新日期:2005-12-01 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 ability to assess the perfusion territories of major cerebral arteries can be a valuable asset to the diagnosis of a number of cerebrovascular diseases. Recently, several arterial spin labeling (ASL) techniques have been proposed for determining the cerebral perfusion territories of individual arteries by three di...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1177
更新日期:2007-11-01 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::Tumor metabolism is directly coupled to tumor blood flow (TBF) and both metabolism and blood flow may be determinants of tumor response to treatment. Since NMR has been used extensively to monitor tumor metabolism noninvasively, development of NMR-based methods for TBF measurement was motivated by the desire to examin...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940050516
更新日期:1992-09-01 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::Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and proton (1H) magnetic resonance spectroscopy (MRS) provide structural and biochemical information, including vascular volume, vascular permeability and tissue metabolism. In this study, we performed analysis of the enhancement characteristic from DCE-...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1511
更新日期:2010-10-01 00:00:00
abstract::The main aim of this study was to employ high-resolution MRI to investigate the spatiotemporal development of pathological features associated with contusive spinal cord injury (SCI) in mice. Experimental mice were subjected to either sham surgery or moderate contusive SCI. A 16.4-T small-animal MR system was employed...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2829
更新日期:2013-02-01 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::With a fixed time to acquire a magnetic resonance (MR) image, time can be spent to acquire better spatial resolution with decrease in signal-to-noise ratio (SNR) or decreased resolution with increase in SNR. This resolution/SNR tradeoff at fixed time has been investigated by a visual rater study using images of ex viv...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1359
更新日期:2009-06-01 00:00:00
abstract::Chemical exchange saturation transfer (CEST)-derived, pH-weighted, amide proton transfer (APT) MRI has shown promise in animal studies for the prediction of infarction risk in ischemic tissue. Here, APT MRI was translated to patients with acute stroke (1-24 h post-symptom onset), and assessments of APT contrast, perfu...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3048
更新日期:2014-02-01 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::Hyperglycemia (blood glucose concentration >150 mg/dL) is common in extremely low gestational age newborns (ELGANs; birth at <28 week gestation). Hyperglycemia increases the risk of brain injury in the neonatal period. The long-term effects are not well understood. In adult rats, hyperglycemia alters hippocampal energ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3910
更新日期:2018-05-01 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::Phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) has gained much interest in schizophrenia research in recent years since it allows the non-invasive measurement of high-energy phosphates and phospholipids in vivo. However, until now only differences in metabolite concentrations between certain brain areas of ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(sici)1099-1492(199912)12:8<483::aid-nbm58
更新日期:1999-12-01 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::Patients with different types of mucopolysaccharidoses (MPS) lack specific lysosomal enzymes, which leads to tissue accumulation and urinary excretion of glycosaminoglycans (GAGs). Since little is known about the molecular composition of the excreted GAG fragments, we used two-dimensional [1H,13C]-correlation nuclear ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.833
更新日期:2003-06-01 00:00:00
abstract::High-energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromis...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1636
更新日期:2011-08-01 00:00:00
abstract::Signal of lung parenchymal tissue from the living rat and mouse lung was detected at 4.7 T with a good signal-to-noise ratio and motion-suppressed artifacts using a short TE gradient-echo sequence. Neither cardiac nor respiratory gating were applied, and animals respired freely during data collection. Mean T(2)* relax...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.706
更新日期:2001-08-01 00:00:00
abstract::Localization techniques are considered an indispensable part of the clinical spectroscopy examination. The results are often a marked improvement in diagnostic information (amplification), but because of the introduction of new artifacts and the more prolonged examination time, some of the undoubted advantage is lost ...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940020525
更新日期:1989-12-01 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 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::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::1H MR spectroscopy was used to correlate the metabolite signals in 66 untreated metastatic brain tumors with the results of Gd-DTPA enhanced MRI. Cubic volumes containing brain metastases of lung cancer (n = 17), mammary carcinoma (n = 24), melanoma (n = 12) and those originating from other tumors (n = 13) were examin...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(SICI)1099-1492(199604)9:2<65::AID-NBM397>
更新日期:1996-04-01 00:00:00
abstract::Organs consist of several types of cells with specialized functions. This cellular localization of function is often referred to as compartmentation. Due to the intrinsic low sensitivity of MR methods it is generally not possible in vivo to obtain images or spectra of single cells. Instead the MRS signal is the sum of...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.692
更新日期:2001-04-01 00:00:00
abstract::Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue contrast. In addition, (...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.2767
更新日期:2012-08-01 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