Abstract：
PURPOSE:To exploit the improved comparability and hardware independency of quantitative MRI, databases of MR physical parameters in healthy tissue are required, to which tissue properties of patients can be compared. In this work, normative values for longitudinal and transverse relaxation times in the brain were established and tested in single-subject comparisons for detection of abnormal relaxation times. METHODS:Relaxometry maps of the brain were acquired from 52 healthy volunteers. After spatially normalizing the volumes into a common space, T1 and T2 inter-subject variability within the healthy cohort was modeled voxel-wise. A method for a single-subject comparison against the atlases was developed by computing z-scores with respect to the established healthy norms. The comparison was applied to two multiple sclerosis and one clinically isolated syndrome cases for a proof of concept. RESULTS:The established atlases exhibit a low variation in white matter structures (median RMSE of models equal to 32 ms for T1 and 4 ms for T2 ), indicating that relaxation times are in a narrow range for normal tissues. The proposed method for single-subject comparison detected relaxation time deviations from healthy norms in the example patient data sets. Relaxation times were found to be increased in brain lesions (mean z-scores >5). Moreover, subtle and confluent differences (z-scores ~2-4) were observed in clinically plausible regions (between lesions, corpus callosum). CONCLUSIONS:Brain T1 and T2 quantitative norms were derived voxel-wise with low variability in healthy tissue. Example patient deviation maps demonstrated good sensitivity of the atlases for detecting relaxation time alterations.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Piredda GF,Hilbert T,Granziera C,Bonnier G,Meuli R,Molinari F,Thiran JP,Kober Tdoi
10.1002/mrm.27927subject
Has Abstractpub_date
2020-01-01 00:00:00pages
337-351issue
1eissn
0740-3194issn
1522-2594journal_volume
83pub_type
杂志文章abstract：:In radiotherapy, target tissues are defined best on MR images due to their superior soft tissue contrast. Computed tomography imaging is geometrically accurate and it is needed for dose calculation and generation of reference images for treatment localization. Co-registration errors between MR and computed tomography ...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章,随机对照试验
doi：10.1002/mrm.24459
更新日期：2013-07-01 00:00:00
abstract：:The mechanism behind previously observed changes in the apparent diffusion coefficient (ADC) during brain activation is not well understood. Therefore, we investigated the signal source and spatial specificity of functional magnetic resonance imaging (fMRI) ADC changes systematically in the visual cortex of cats using...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.21074
更新日期：2006-12-01 00:00:00
abstract：:A cerebrospinal fluid (CSF)-suppressed flow-attenuated inversion recovery (FLAIR) double-shot diffusion echo-planar imaging (EPI) sequence was developed and used, along with a non-CSF-suppressed version of the sequence, to determine the extent of the contribution of CSF partial-volume averaging to the apparent diffusi...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910370117
更新日期：1997-01-01 00:00:00
abstract：:The aim of this study was to quantify changes in thoracic aortic wall shear stress (WSS) in asymptomatic patients with Marfan syndrome (MFS) compared with healthy controls. WSS in the thoracic aorta was quantified based on time-resolved 3D phase contrast MRI with three-directional velocity encoding (4D flow MRI, tempo...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.24562
更新日期：2013-10-01 00:00:00
abstract：:We present new diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models. The phantom design permits the application of imaging parameters that are typically employed in studies of the human brain. The phantoms were made of small-diameter acrylic fibers, chose...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.21789
更新日期：2008-12-01 00:00:00
abstract：:The fate of the 13C label arising from [U-13C]succinate in rabbit renal proximal convoluted tubular (PCT) cells, incubated with [U-13C]succinate, was investigated by 13C NMR spectroscopy of the perchloric acid extracts of the cell pellets. The 13C label of [U-13C]succinate was predominantly metabolized into glutamate,...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910140114
更新日期：1990-04-01 00:00:00
abstract：PURPOSE:The use of electromagnetic (EM) modeling is critical for specific absorption rate (SAR) characterization in parallel transmission MRI. Radiofrequency arrays that include decoupling networks can be difficult to characterize accurately in simulation. A practical method of simplifying modeling is to exclude the de...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.25504
更新日期：2015-11-01 00:00:00
abstract：:The dependence of 1/T1 on the magnetic field strength (the relaxation dispersion) has been measured at 37 degrees C on autopsy samples of human brain gray and white matter at field strengths corresponding to proton Larmor frequencies between 10 kHz and 50 MHz (0.0002-1.2 T). Additional measurements of 1/T1 and 1/T2 ha...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910160212
更新日期：1990-11-01 00:00:00
abstract：:Electron paramagnetic resonance imaging using nitroxides is a powerful method for visualizing the redox status modulated by oxidative stress in vivo. Typically, however, data acquisition times have been too slow to obtain a sufficient number of projections for three-dimensional images, when using continuous wave-elect...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.22598
更新日期：2011-01-01 00:00:00
abstract：:Passive MR tracking of catheters and guidewires is usually done by dynamically imaging a single thick slab, subtracting a baseline image, and combining the result with a previously acquired MR angiogram. In the in vitro and in vivo experiments reported here, it is demonstrated that this approach may be greatly simplif...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/1522-2594(200101)45:1<17::aid-mrm1003>3.0.
更新日期：2001-01-01 00:00:00
abstract：PURPOSE:The diseased myocardium lacks metabolic flexibility and responds to stimuli differently compared with healthy hearts. Here, we report the use of hyperpolarized 13C NMR spectroscopy to detect sudden changes in cardiac metabolism in isolated, perfused rat hearts in response to adrenergic stimulation. METHODS:Met...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.25419
更新日期：2015-08-01 00:00:00
abstract：:Skeletal muscle triglycerides are markers for insulin resistance in type 2 diabetes. Recently, MR spectroscopy was adapted for in vivo measurement of triglycerides in animal models and for the characterization of new therapeutic approaches. Because of small MR spectroscopy voxel sizes used in skeletal muscles, surface...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.22149
更新日期：2009-10-01 00:00:00
abstract：:We studied the fluxes of a potassium congener (Rb(+)) in mouse hearts by (87)Rb MRS at 8.4T. The hearts were loaded with Rb(+) by perfusion with Krebs-Henseleit buffer, in which 50% of K(+) was substituted with Rb(+). We initiated Rb(+) efflux by changing the perfusion medium to Rb(+)-free buffer. Spectra were acquire...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.20450
更新日期：2005-05-01 00:00:00
abstract：:The study of lung perfusion in normal and diseased subjects is of great interest to physiologists and physicians. In this work we demonstrate the application of a liquid-phase hyperpolarized (HP) carbon-13 ((13)C) tracer to magnetic resonance imaging (MRI) of the pulmonary vasculature and pulmonary perfusion in a porc...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.21168
更新日期：2007-03-01 00:00:00
abstract：PURPOSE:Phosphorus spectroscopy (31 P-MRS) is a proven method to probe cardiac energetics. Studies typically report the phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio. We focus on another 31 P signal: inorganic phosphate (Pi), whose chemical shift allows computation of myocardial pH, with Pi/PCr providing ...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.28494
更新日期：2021-03-01 00:00:00
abstract：:Proton T(1rho)-dispersion MRI is demonstrated for indirect, in vivo detection of (17)O in the brain. This technique, which may be readily implemented on any clinical MRI scanner, is applied towards high-resolution, quantitative mapping of cerebral blood flow (CBF) in the rat by monitoring the clearance of (17)O-enrich...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.10403
更新日期：2003-03-01 00:00:00
abstract：PURPOSE:To develop and evaluate a method for volumetric contrast-enhanced MRI of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography (MRA) using a single injection of contrast agent. METHODS:An interleaved variable density (IVD) undersampling pattern was implemented i...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.25195
更新日期：2015-03-01 00:00:00
abstract：PURPOSE:To obtain whole-brain high-resolution T2 maps in 2 minutes by combining simultaneous multislice excitation and low-power PINS (power independent of number of slices) refocusing pulses with undersampling and a model-based reconstruction. METHODS:A multi-echo spin-echo sequence was modified to acquire multiple s...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.27890
更新日期：2019-12-01 00:00:00
abstract：:A method is described for the correction of geometric distortions occurring in echo planar images. The geometric distortions are caused in large part by static magnetic field inhomogeneities, leading to pixel shifts, particularly in the phase encode direction. By characterizing the field inhomogeneities from a field m...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910340111
更新日期：1995-07-01 00:00:00
abstract：:The ability to generate in vivo maps of lactate may have significant diagnostic utility in staging and treatment planning of a wide variety of cancers. The double selective multiple quantum filter technique (SelMQC) has been shown to be effective for nonlocalized detection of lactate with little or no interference fro...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.21659
更新日期：2008-08-01 00:00:00
abstract：:Myocardial blood flow varies during the cardiac cycle in response to pulsatile changes in epicardial circulation and cyclical variation in myocardial tension. First-pass assessment of myocardial perfusion by dynamic contrast-enhanced MRI is one of the most challenging applications of MRI because of the spatial and tem...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.22538
更新日期：2010-12-01 00:00:00
abstract：:High-resolution magic-angle spinning has become a valuable tool to study biologic samples; however, there are only a few high-resolution magic-angle spinning methodologies that have been explored specifically to deal with small semisolid biomaterials such as tissues. Here, we report a novel high-resolution (1)H NMR sp...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.22231
更新日期：2010-02-01 00:00:00
abstract：:This article describes an EPR spectrometer specifically designed and constructed for EPR spectroscopy in humans. The spectrometer is based on a permanent magnet, suitable for measurements at 1200 MHz. The magnet has a full 50 cm gap between the poles, which facilitates accurate and comfortable placement of the subject...
journal_title：Magnetic resonance in medicine
pub_type： 临床试验,杂志文章
doi：10.1002/mrm.20689
更新日期：2005-11-01 00:00:00
abstract：PURPOSE:Define criteria for selection of optimal flip angle sets for T1 estimation and evaluate effects on T1 mapping. THEORY AND METHODS:Flip angle sets for spoiled gradient echo-based T1 mapping were selected by minimizing T1 estimate variance weighted by the joint density of M0 and T1 in an initial acquisition. The...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.25920
更新日期：2016-09-01 00:00:00
abstract：:Dynamic contrast-enhanced MRI data in vertebral bone marrow (vBM) are currently analyzed with descriptive indices. The purpose of this study was to develop and evaluate a quantitative approach, considering the tissue composition of vBM. Therefore, a measurement of the water fraction, f(wat), and the precontrast relaxa...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.22415
更新日期：2010-07-01 00:00:00
abstract：:We have noninvasively produced low-resolution, quantitative nuclear magnetic resonance images of cerebral blood flow in 2-ml voxels in eight cats. Typical signal-to-noise of 4 to 1 was obtained in cerebral voxels in 16.5-s epochs. Mean flow during normocapnia (paCO2 = 39 +/- 4 mm Hg) and hypercapnia (paCO2 = 62 +/- 4 ...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910280105
更新日期：1992-11-01 00:00:00
abstract：:The time evolution of water diffusion, perfusion, T1, and T2 is investigated at high magnetic field (8.5 T) following permanent middle cerebral artery occlusion in the rat. Cerebral blood flow maps were obtained using arterial spin tagging. Although the quantitative perfusion measurements in ischemic tissue still pose...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/(sici)1522-2594(199903)41:3<479::aid-mrm9>
更新日期：1999-03-01 00:00:00
abstract：:Localized 1H NMR homonuclear J editing spectroscopy was used to measure the concentration of 2-pyrrolidinone (PRDN) in the human occipital lobe of five normal and six epileptic subjects taking vigabatrin. PRDN is a lactam cyclization product of gamma-aminobutyric acid (GABA). From a localized volume of 13.5 cm3 in the...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/(sici)1522-2594(199905)41:5<889::aid-mrm6>
更新日期：1999-05-01 00:00:00
abstract：:The most widely-used functional magnetic resonance imaging (fMRI) technique is based on the blood oxygenation level dependent (BOLD) effect, which requires at least partial uncoupling between cerebral blood flow (CBF) and oxygen consumption changes during increased mental activity. To compare BOLD and CBF effects duri...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910380110
更新日期：1997-07-01 00:00:00
abstract：:Orientational anisotropy of T2 and T1 relaxation times, diffusion, and magnetization transfer has been investigated for six different tissues: tendon, cartilage, kidney, muscle, white matter, and optic nerve. Relaxation anisotropy was observed for tendon and cartilage, and diffusional anisotropy was measured in kidney...
journal_title：Magnetic resonance in medicine
pub_type： 杂志文章
doi：10.1002/mrm.1910320508
更新日期：1994-11-01 00:00:00
