Abstract：
:This work discusses the effect of sampling time on noise, signal-to-noise and contrast-to-noise ratios in magnetic resonance imaging. A simple imaging experiment is performed to demonstrate the effect of sampling time on noise, confirming theoretical expectations that doubling the sampling time while decreasing the read gradient strength by a factor of two reduces statistical noise to 1/square root 2 of its original level. This result suggests that sampling time should be maximized within the constraints of the pulse sequence: namely, that sampling time should be increased and read gradient strength decreased as TE is increased. Revised expressions for signal-to-noise and contrast-to-noise ratios are presented based on the assumption that sampling time increases linearly with echo delay time above a certain minimum TE value. The revised expressions are then used to derive new predictions of the interpulse delay times that maximize signal-to-noise and contrast-to-noise ratios in spin-echo imaging. It is demonstrated that sampling times are critical in determining whether T1-weighted or T2-weighted sequences produce superior tissue contrast in spin-echo imaging.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Hendrick REdoi
10.1016/0730-725x(87)90481-4subject
Has Abstractpub_date
1987-01-01 00:00:00pages
31-7issue
1eissn
0730-725Xissn
1873-5894pii
0730-725X(87)90481-4journal_volume
5pub_type
杂志文章abstract：PURPOSE:To develop a RF coil system for joint imaging of intracranial and extracranial arterial vessel wall at 3T. MATERIALS AND METHOD:The coil system consists of a 24-channel head coil combined with an 8-channel carotid coil. It is compared with a standard coil configuration (12-channel head coil+4-channel neck coil...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.10.018
更新日期：2017-02-01 00:00:00
abstract：:The hippocampal formation possesses an important role in the development and maintenance of short-term memory. In this study, magnetic resonance imaging (MRI) and gross histology were used to quantify the volume of the hippocampal formation in canines. High resolution MRI, using 1 mm thick slices and an intraplanar re...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(95)02083-6
更新日期：1996-01-01 00:00:00
abstract：:Magnetic resonance imaging (MRI) and spectroscopy (MRS) have contributed considerably to clinical radiology, and a variety of MR techniques have been developed to evaluate pathological processes as well as normal tissue biology at the cellular and molecular level. However, in comparison to nuclear imaging, MRI has rel...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2016.12.008
更新日期：2017-05-01 00:00:00
abstract：BACKGROUND AND PURPOSE:Diffusion MRI characteristics have been used as biomarkers to guide prognosis in cerebral pathologies including brain metastases. The measurement of ADC is often described poorly in clinical and research studies with little detail given to the practical considerations of where to place ROIs, whic...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.12.010
更新日期：2014-04-01 00:00:00
abstract：:Primary epiploic appendagitis (PEA) occurs secondary to inflammation of an epiploic appendage, and is considered to be a rare cause of acute abdomen. In this case report, we describe the magnetic resonance imaging (MRI) findings of PEA correlated with computed tomographic (CT) findings. MRI findings included an oval s...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(02)00478-2
更新日期：2002-01-01 00:00:00
abstract：:The purpose of this study was to compare the relative conspicuity of the pancreaticobiliary tree on respiratory-triggered three-dimensional turbo spin echo (3D TSE RT) and breath hold single-shot turbo spin echo (SSTSE BH) acquisitions respectively in MRCP imaging. Both techniques were applied to 61 patients with clin...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(99)00074-0
更新日期：1999-11-01 00:00:00
abstract：:Tissue contrast obtained using fast spin-echo (FSE) and conventional spin-echo (SE) sequences is not identical and a number of mechanisms are thought to contribute to these contrast differences. The effect of stimulated echoes has previously been apparently ruled out as a contributing mechanism. Signal-to-noise ratios...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(95)02110-f
更新日期：1996-01-01 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
abstract：:We used magnetic resonance imaging (MRI) and water-suppressed proton MR spectroscopic imaging (1H MRSI) to study the effects of human immunodeficiency virus (HIV) infection on the brain. Our recent in vivo finding of lower N-acetylaspartate (NAA), a putative marker of neurons, in the supraventricular brain of cognitiv...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(94)92460-0
更新日期：1994-01-01 00:00:00
abstract：:We implemented pseudo-continuous ASL (pCASL) with 2D and 3D balanced steady state free precession (bSSFP) readout for mapping blood flow in the human brain, retina, and kidney, free of distortion and signal dropout, which are typically observed in the most commonly used echo-planar imaging acquisition. High resolution...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.03.024
更新日期：2013-09-01 00:00:00
abstract：:In vivo spin-lattice relaxation times, T1, of water and lipid protons of normal and atrophic muscles were measured, using the spatially resolved spectroscopy (SPARS) sequence, in a genetic avian model of myopathy. These T1 values were compared with those of the hypertrophic muscles. Although the water T1 values of mus...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(89)90550-x
更新日期：1989-05-01 00:00:00
abstract：:1H-nuclear magnetic resonance (NMR) measurements have been carried out on a banded sandstone to investigate the effects of structural inhomogeneities on the fluid dynamics of the sample as a whole. The results obtained from average propagator measurements (the probability of a displacement z in a time delta or P delta...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(98)00043-5
更新日期：1998-06-01 00:00:00
abstract：:The objective of this study was to measure T2* values of the normal human lung in vivo during breathhold using a rapid gradient-echo sequence with ultra-short echo times (TE). A sagittal slice of the right lung was imaged in six volunteers with various TE ranging from 0.5 ms to 5 ms using a clinical 1.5 Tesla MR scann...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(99)00047-8
更新日期：1999-09-01 00:00:00
abstract：:In congenital diaphragmatic hernia (CDH), lung hypoplasia and secondary pulmonary hypertension are the major causes of death and severe disability. Based on new therapeutic strategies survival rates could be improved to up to 80%. However, after surgical repair of CDH, long-term follow-up of these pediatric patients i...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2015.08.003
更新日期：2015-12-01 00:00:00
abstract：PURPOSE:To perform comprehensive in vitro experiments using six-directional icosahedral flow encoding (ICOSA6) 4D flow magnetic resonance imaging (MRI) under various scan conditions to analyze the robustness of velocity and turbulence quantification. MATERIALS AND METHODS:In vitro flow phantoms with steady flow rates ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2020.06.020
更新日期：2020-10-01 00:00:00
abstract：:In porous material research, one main interest of nuclear magnetic resonance diffusion (NMR) experiments is the determination of the shape of pores. While it has been a longstanding question if this is in principle achievable, it has been shown recently that it is indeed possible to perform NMR-based diffusion pore im...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2013.03.027
更新日期：2013-09-01 00:00:00
abstract：:Using both quantitative computer-assisted analysis and visual estimation the MR imaging response of brain metastases to whole-brain radiotherapy (WBRT) was prospectively studied in 49 patients. Compared to the computer-assisted analysis, the precision of the visual estimation (by two readers in conference) of tumor re...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(96)00024-0
更新日期：1997-01-01 00:00:00
abstract：:Gd-DOTA contrast enhancement of MR images was evaluated on induced mammary tumors in female rats. A single intravenous injection of the carcinogenic N-nitrosourea ENU was administered to Wistar rats; this simple treatment led to a high percentage of mammary tumors without causing death. All the induced tumors were ade...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(90)90215-n
更新日期：1990-01-01 00:00:00
abstract：:Systems investigated with NMR spectroscopy are sometimes heterogeneous with respect to chemical composition, rates of chemical exchange, and other properties influencing magnetic resonance parameters. A method was developed to spatially encode reaction kinetic information and produce NMR images sensitive to chemical e...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(88)90125-7
更新日期：1988-09-01 00:00:00
abstract：PURPOSE:The purpose of this study was to assess relationships between intramuscular adipose tissue (IntraMAT) content determined by MRI and intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) determined by (1)H magnetic resonance spectroscopy ((1)H MRS) or echo intensity determined by B-mode ultrasonograp...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2015.12.038
更新日期：2016-05-01 00:00:00
abstract：:The misunderstanding of the labeling for an "MR conditional" respiratory ventilator system resulted in the placement of this device, which had substantial ferromagnetic components, too close to a 3-T magnetic resonance (MR) system, causing a projectile incident. Magnetic resonance imaging health care professionals sho...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2011.07.002
更新日期：2011-10-01 00:00:00
abstract：:Functional T1ρ mapping has been proposed as a method to assess pH and metabolism dynamics in the brain with high spatial and temporal resolution. The purpose of this work is to describe and evaluate a variant of the spin-locked echo-planar imaging sequence for functional T1ρ mapping at 3T. The proposed sequence rapidl...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2014.07.010
更新日期：2014-11-01 00:00:00
abstract：:Magic-angle sample spinning is one of the cornerstones in high-resolution NMR of solid and semisolid materials. The technique enhances spectral resolution by averaging away rank 2 anisotropic spin interactions, thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. In principle, i...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2004.11.067
更新日期：2005-02-01 00:00:00
abstract：:In this paper, a new reaction-diffusion model with viscous stress tensor is proposed for modeling the diffusion and invasion of brain glioma cells, which is based on the model in Yuan J.J., Liu L., Hu Q.M. Mathematical modeling of brain glioma growth using modified reaction-diffusion equation on brain MR images. Compu...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2015.10.012
更新日期：2016-02-01 00:00:00
abstract：:Dysfunction of the corticolimbic circuitry has been highlighted in social anxiety disorder (SAD) during social stimuli. However, few studies have investigated functional connectivity in SAD during the resting state, which may improve our understanding of SAD pathophysiology. The aim of this study was to investigate wh...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2011.02.013
更新日期：2011-06-01 00:00:00
abstract：:Magnetic resonance imaging (MRI) is a completely noninvasive modality that has shown significant promise for the evaluation of the cardiovascular system. Our imaging technique employed electrocardiographic (ECG) gating, which resulted in well-resolved images of the cardiac structures. Patients and animals with a varie...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/0730-725x(84)90002-x
更新日期：1984-01-01 00:00:00
abstract：:The discrimination of tumor boundaries from normal tissue, as well as the evaluation of tissue heterogeneity and tumor grading often continue to pose a challenge in MRI. Although yielding promising results in various fields of medical imaging, two- dimensional (2D) texture analysis in MRI has, until now, demonstrated ...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(03)00201-7
更新日期：2003-11-01 00:00:00
abstract：:Atherosclerotic plaques in the bifurcation of the carotid arteries can pose a significant health risk due to possible plaque rupture and subsequent stroke. The assessment of plaques, and evaluation of the risk they pose, can be performed with Black-Blood (BB) vessel wall magnetic resonance imaging. However, resolution...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/j.mri.2017.04.011
更新日期：2017-07-01 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：:The HASTE (half-Fourier acquisition single-shot turbo spin-echo) technique delivers images with T2-weighting in about half a second and could be ideal for fast dynamic studies when T2-weighting is needed. We evaluated cardiac-triggered HASTE to study cervical spine flexion/extension. The cervical spines of ten asympto...
journal_title：Magnetic resonance imaging
pub_type： 杂志文章
doi：10.1016/s0730-725x(98)00176-3
更新日期：1999-04-01 00:00:00
