Abstract:
:A new phantom and evaluation method for experimental evaluation of 1H-magnetic resonance spectroscopy single volume localization techniques regarding signal contamination (C), defined as the part of the signal originating outside the volume of interest, is presented. The quality assessment method is based on a spherical phantom with an oil/water interface in order to reduce susceptibility effects, and applied for stimulated-echo acquisition method (STEAM) and spin-echo (SE) sequences, echo times of 270, 135, and 10 ms, and cubic volumes of interest (VOI) of 1(3), 1.5(3), 2(3), 2.5(3), and 3(3) cm3. To be able to mimic measurements of the contamination in three dimensions the physical gradients representing the three orthogonal directions for slice selection were shifted in the pulse sequences. Contamination values in one dimension differed between 6.5% and 8.4% in SE sequences, and between 0.7% and 13.8% in STEAM sequences. In STEAM sequences a decrease of C with increasing VOI size was observed while SE sequences showed comparable C values for the different VOI sizes tested. The total contamination in three dimensions were 19% and 18% in SE and STEAM sequences with a TE of 270 ms, and 7% in a STEAM sequence with a TE of 10 ms, respectively. The presented evaluation method is easily applied to the new phantom and showed high reproducibility.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Burtscher IM,Johansson E,Holtås S,Ståhlberg Fdoi
10.1016/s0730-725x(99)00076-4subject
Has Abstractpub_date
1999-12-01 00:00:00pages
1511-9issue
10eissn
0730-725Xissn
1873-5894pii
S0730-725X(99)00076-4journal_volume
17pub_type
杂志文章abstract::We present the case of a 44-year-old man who complained of cervical pain. He was treated with physiotherapy and analgetics. Because of persistent pain, computed tomography (CT) scan and MRI were performed. They revealed an osteolytic destruction of the fourth cervical vertebra. The patient was treated surgically for r...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章,评审
doi:10.1016/j.mri.2004.01.006
更新日期:2004-05-01 00:00:00
abstract::Present knowledge suggests that in glioblastoma multiforme the value of the apparent diffusion coefficient (ADC) is elevated in the solid part and hyperintense in T1, in spite of the elevated cellularity, and also in areas where peritumoral vasogenic edema is present. The purpose of our study has been to verify in viv...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(02)00594-5
更新日期:2002-11-01 00:00:00
abstract:OBJECTIVE:To investigate T2 mapping as a possible marker for low-grade human articular cartilage lesions during a one-year follow-up, possible changes during the follow-up and compare the reliability and sensitivity of these measurements on high-field (3 T) and ultra-high-field (7 T) MRI scanners. DESIGN:Twenty-one pa...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.09.021
更新日期:2019-01-01 00:00:00
abstract:PURPOSE:Visual review of individual spectra in magnetic resonance spectroscopic imaging (MRSI) data benefits from the application of spectral smoothing; however, if this processing step is applied prior to spectral analysis this can impact the accuracy of the quantitation. This study aims to analyze the effect of spect...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2020.04.013
更新日期:2020-07-01 00:00:00
abstract::A model of MRI signal intensity which is a function of perfusion is developed based upon the assumption that biological tissue can be represented by a blood and tissue compartment. The longitudinal magnetization is derived from the Bloch equations which are modified to model the magnetization in both the blood and tis...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(91)90095-4
更新日期:1991-01-01 00:00:00
abstract::Susceptibility-weighted imaging (SWI) is a valuable technique for high-resolution imaging of brain vasculature that greatly benefits from the emergence of higher field strength MR scanners. Autocalibrating partially parallel imaging techniques can be employed to reduce lengthy acquisition times as long as the decrease...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2008.08.003
更新日期:2009-05-01 00:00:00
abstract::In this paper the effects of reducing the flip angle of the 90-degree observation pulse in inversion recovery imaging are described and analyzed. When incorporated in an IR sequence with a short inversion time (STIR), reduction to the 90-degree pulse allows a significant shortening of the repetition time without loss ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(91)90418-l
更新日期:1991-01-01 00:00:00
abstract:PURPOSE:The state-of-the-art method to quantify sodium concentrations in vivo consists in a fully relaxed 3D spin-density (SD) weighted acquisition. Nevertheless, most sodium MRI clinical studies use short-TR SD acquisitions to reduce acquisition durations. We present a clinically viable implementation of the Variable ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2019.01.015
更新日期:2019-05-01 00:00:00
abstract::Tissue water molecules reside in different biophysical compartments. For example, water molecules in the vasculature reside for variable periods of time within arteries, arterioles, capillaries, venuoles and veins, and may be within blood cells or blood plasma. Water molecules outside of the vasculature, in the extrav...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章,评审
doi:10.1016/j.mri.2007.02.006
更新日期:2007-07-01 00:00:00
abstract:OBJECTIVE:In magnetic resonance-guided breast vacuum biopsies, the contrast agent for targeting suspicious lesions can typically be applied only once during an intervention, due to the slow elimination of the gadolinium chelate from the extracellular fluid space. This study evaluated the feasibility of diffusion-weight...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.12.006
更新日期:2017-05-01 00:00:00
abstract::The results of a magnetic resonance spin-spin relaxation analysis and broad-line magnetic resonance imaging (MRI) (gradient-echo and stray-field imaging) study of water and water transport in Portland cement pastes are presented. The effect of varying the cure conditions and the water to cement (w/c) ratio of the samp...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(98)00072-1
更新日期:1998-06-01 00:00:00
abstract::The midcalf muscles of eight patients who had peripheral arterial occlusive disease were evaluated by exercise MRI before and after bypass surgery or percutaneous transluminal angioplasty. MRI showed a high intensity of these muscles, especially the posterior muscles, after exercise in all patients before intervention...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(95)00018-c
更新日期:1995-01-01 00:00:00
abstract::Diffraction ideas were first introduced to NMR by Mansfield and Grannell. Here we compare "Mansfield (k-space) diffraction" with the "diffusive (q-space) diffraction," noting their similarities and differences. The diffusive-diffraction concept is extremely helpful in elucidating the Pulsed Gradient Spin Echo NMR expe...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(96)00152-x
更新日期:1996-01-01 00:00:00
abstract::Magnetic resonance spectroscopy (MRS) is ideally suited for physiology-neurochemistry experiments with the living brain and particularly for studies on the primary visual cortex (striate cortex or area V1). Yet, the highly convoluted form of the human V1 has thus far prevented the performance of MRS investigations tha...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2007.03.008
更新日期:2007-07-01 00:00:00
abstract::Functional magnetic resonance imaging (fMRI) was performed on a conventional 1.5 T scanner by means of a modified FLASH-technique at temporal resolutions of 80 and 320 ms. The method's stability was assessed by phantom measurements and by investigation of three volunteers resulting in a low amplitude (3%) periodic (4 ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(96)00021-5
更新日期:1996-01-01 00:00:00
abstract::The CNS involvement is frequently found in human immunodeficiency virus (HIV) infection. The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement in neurologically asymptomatic HIV-infected patients with normal MR imagings and to find the corre...
journal_title:Magnetic resonance imaging
pub_type: 临床试验,杂志文章
doi:10.1016/s0730-725x(00)00173-9
更新日期:2000-09-01 00:00:00
abstract::It is a big challenge to segment magnetic resonance (MR) images with intensity inhomogeneity. The widely used segmentation algorithms are region based, which mostly rely on the intensity homogeneity, and could bring inaccurate results. In this paper, we propose a novel region-based active contour model in a variationa...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.10.010
更新日期:2013-05-01 00:00:00
abstract::Wall shear stress (WSS) is a relevant hemodynamic indicator of the local stress applied on the endothelium surface. More specifically, its spatiotemporal distribution reveals crucial in the evolution of many pathologies such as aneurysm, stenosis, and atherosclerosis. This paper introduces a new solution, called PaLMA...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2020.08.017
更新日期:2020-12-01 00:00:00
abstract::The mapping of the human brain white matter fiber networks relative to deep subcortical and cortical gray matter requires high spatial resolution which is challenged by the low signal-to-noise ratio. The purpose of this short report was to introduce a whole brain high spatial resolution diffusion tensor imaging (DTI) ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2008.10.007
更新日期:2009-06-01 00:00:00
abstract::Qualitative and quantitative proton magnetic resonance imaging techniques were applied to persimmon (Diospyros kaki cv 'Fuyu') fruit during development and post-harvest ripening. Spin-lattice (T(1)) relaxation times in mesocarp parenchyma and vascular tissue exhibited a sigmoidal pattern of increase leading to commerc...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(03)00082-1
更新日期:2003-07-01 00:00:00
abstract::Measurements of arterial input function (AIF) can have large systematic errors at standard contrast agent doses in dynamic contrast enhanced MRI (DCE-MRI). We compared measured AIFs from low dose (AIFLD) and standard dose (AIFSD) contrast agent injections, as well as the AIF derived from a muscle reference tissue and ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2015.10.025
更新日期:2016-02-01 00:00:00
abstract::Most modern techniques for functional magnetic resonance imaging (fMRI) rely on blood-oxygen-level-dependent (BOLD) contrast as the basic principle for detecting neuronal activation. However, the measured BOLD effect depends on a transfer function related to neurophysiological changes accompanying electrical neural ac...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2008.02.006
更新日期:2008-11-01 00:00:00
abstract::Blood circulation is an important determinant of the biodistribution of superparamagnetic iron oxide nanoparticles. Here we present a magnetic resonance imaging (MRI) technique based on the use of ultrafast echo times (UTE) for the noninvasive determination of blood half-lives at high particle concentrations, when con...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2015.06.017
更新日期:2015-11-01 00:00:00
abstract::The purpose of this study was to develop a novel intravascular loopless monopole antenna (ILMA) design specifically for imaging of small vessel walls. The ILMA consisted of an unshielded, low-friction guide wire and a tuning/matching box. The material of the guide wire was nitinol and it was coated with polyurethane. ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.06.032
更新日期:2013-01-01 00:00:00
abstract::Microscopic magnetic resonance elastography is a high-resolution method for visualizing shear waves and assessing the biomechanical viscoelastic properties of small biological samples. In this work, we used error propagation to develop a simple analytical model that relates the signal-to-noise ratio of MR magnitude im...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.09.040
更新日期:2007-01-01 00:00:00
abstract::The objective of this study was to describe magnetic resonance (MR) findings with a 1.5T imager for hepatic parenchymal changes after proton beam radiotherapy. Thirty-two patients who received proton radiotherapy with doses of 50-87 Gy underwent MR imaging 1-75 months (mean 22 months) after the start of irradiation. A...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(00)00152-1
更新日期:2000-07-01 00:00:00
abstract:UNLABELLED:The conventional diagnostic work-up of a patient suspected of having a vascular cause for stridor, or dysphagia, includes esophagography and bronchoscopy to delineate the abnormal structure without imaging the structure itself. Cine-angiography is regarded as the golden standard, but is not routinely perform...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(97)00245-2
更新日期:1998-01-01 00:00:00
abstract::A new method for generating diffusion contrast in magnetic resonance imaging is presented. This technique is robust enough to allow implementation on conventional imaging systems without hardware modifications. Results from phantom measurements are reported. Qualitative contrast changes in magnetic resonance images de...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(93)90069-p
更新日期:1993-01-01 00:00:00
abstract::It has been shown recently that quantitative T2-maps may be measured by acquisition of a series of at least eight T2-weighted SNAPSHOT FLASH images. These measurements require a relaxation delay of 10-15 s after each T2-weighted image for the complete relaxation of the spin system. This results in long measuring times...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(95)00004-z
更新日期:1995-01-01 00:00:00
abstract::We studied 26 cases of abdominal aortic aneurysm with magnetic resonance imaging (MRI), computed tomography (CT), ultrasonography (US), and angiography. Data acquired were compared to those obtained at surgery. Diameter of the aneurysm was correctly defined in all cases by CT and MRI, while angiography underestimated ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(90)90089-k
更新日期:1990-01-01 00:00:00