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 cognitively impaired HIV-seropositive patients (CISP) compared to noninfected controls was replicated in a new cohort of 13 CISP patients and extended to include 10 high-risk homosexual HIV-seronegative controls. Throughout the supraventricular brain the ratio of NAA to choline-containing metabolites (NAA/Cho) was lower in CISP subjects than in high-risk controls (1.98 +/- 0.36 vs. 2.35 +/- 0.29, p = 0.016), and the ratio of NAA to creatine-containing metabolites (NAA/Cr) was also lower in CISP subjects than in high-risk controls (3.02 +/- 0.44 vs. 3.56 +/- 0.39, p = 0.007) with Cho/Cr unchanged in both groups. These findings indicate a NAA reduction which suggests neuron loss and/or dendritic and axonal damage. Homosexual high-risk HIV-seronegative controls had metabolite measures similar to previously studied heterosexual HIV-seronegative controls. NAA measures in six cognitively normal HIV-seropositive subjects (CNSP) (NAA/Cho = 2.34 +/- 0.39, NAA/Cr = 3.42 +/- 0.69) were similar to those of controls and tended to be increased relative to those in cognitively impaired HIV-seropositive subjects. This study demonstrates that reduced NAA in the supraventricular brain is associated with the development of severe cognitive impairments secondary to HIV infection and that 1H MRSI methodology reliably detects HIV effects on the brain.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Meyerhoff DJ,MacKay S,Poole N,Dillon WP,Weiner MW,Fein Gdoi
10.1016/0730-725x(94)92460-0subject
Has Abstractpub_date
1994-01-01 00:00:00pages
653-9issue
4eissn
0730-725Xissn
1873-5894pii
0730-725X(94)92460-0journal_volume
12pub_type
杂志文章abstract::In certain nuclear magnetic resonance (NMR) applications in which accessibility to the gantry is limited, performing optimal tuning and matching represents a major problem. Here, we discuss a method of tuning NMR probe circuits and matching their impedances which uses cables with different impedance values. This simpl...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(99)00051-x
更新日期:1999-09-01 00:00:00
abstract:PURPOSE:To develop a protocol to non-invasively measure and map fat fraction, fat/(fat+water), as a function of age in the adult thymus for future studies monitoring the effects of interventions aimed at promoting thymic rejuvenation and preservation of immunity in older adults. MATERIALS AND METHODS:Three-dimensional...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.03.016
更新日期:2018-07-01 00:00:00
abstract::Focal brain ischemia was induced by middle cerebral artery occlusion in the rat. The volume of cerebral damage was determined 2 days later by MRI in vivo and in the same animals histologically. The edema volume as measured by MRI and the histologically determined infarction was highly correlated. As a consequence, the...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(92)90411-r
更新日期:1992-01-01 00:00:00
abstract::Poly(L-glutamic acid) (PGA)-cystamine-[gadolinium (Gd)-DO3A] was prepared in high yield with a high Gd-DO3A conjugation efficiency. Approximately 55% of the carboxylic groups in PGA were loaded with Gd-DO3A via cystamine as the spacer. Cystamine can be readily cleaved by endogenous thiols to release the Gd(III) chelat...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.03.009
更新日期:2006-09-01 00:00:00
abstract::Rapid maturational brain changes occur during adolescence--a time associated with risk-taking behaviors and improvements in cognition. The present study examined the relationship between white matter (WM) microstructure, impulsive behavior and response inhibition in female and male adolescents. Twenty-one healthy adol...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.03.012
更新日期:2006-09-01 00:00:00
abstract::The analysis of functional magnetic resonance imaging (fMRI) data involves multiple stages of data pre-processing before the activation can be statistically detected. Spatial smoothing is a very common pre-processing step in the analysis of functional brain imaging data. This study presents a broad perspective on the ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2007.08.006
更新日期:2008-05-01 00:00:00
abstract::Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) and microimaging experiments have been performed to study the diffusion of liquid alkanes into a variety of semicrystalline polyethylene (PE) samples. The results highlight the importance of the crystalline phase in controlling the diffusion process in terms...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(98)00032-0
更新日期:1998-06-01 00:00:00
abstract::Until recently, NMR imaging with intermolecular multiple-quantum coherences (iMQCs) has been based on the acquisition of a single echo. In vivo studies of iMQC image contrast would greatly benefit from a method that could acquire several orders of quantum coherence during the same acquisition. This would enable compar...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2004.10.019
更新日期:2004-12-01 00:00:00
abstract::In the present work, we reported a new nuclear Overhauser enhancement (NOE)-mediated magnetization transfer (MT) signal at around -1.6ppm (NOE(-1.6)) in rat brain and investigated its application in the detection of acute ischemic stroke in rodent model. Using continuous wave (CW) MT sequence, the NOE(-1.6) is reliabl...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.05.002
更新日期:2016-10-01 00:00:00
abstract::Several recent articles have assessed the relative efficiency of nuclear magnetic resonance (NMR) pulse sequences. One consideration that has received little attention is the effect on image contrast of displaying images without information on the sign of the reconstructed signals. The radiofrequency receivers current...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(84)90193-0
更新日期:1984-01-01 00:00:00
abstract::Automatic segmentation of different types of tissue from magnetic resonance images is of great importance for clinical and research applications, particularly large-scale and longitudinal studies of brain pathology. We developed a fully automated algorithm for the segmentation of lateral ventricles from cranial magnet...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.08.013
更新日期:2006-12-01 00:00:00
abstract::For a number of reasons, it is desirable to fabricate coils which, for a known current, shall produce predetermined values of the magnetic field intensity at a number of points within a nuclear magnetic resonance imager. The calculation of the magnetic field intensity at a set of points involves the integration of the...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(89)90524-9
更新日期:1989-11-01 00:00:00
abstract::Liver fibrosis determines the functional liver reserve. Several studies have reported that the apparent diffusion coefficient (ADC) values of diffusion-weighted magnetic resonance imaging (DW-MRI) can assess liver fibrosis. We investigated whether DW-MRI predicts postoperative hepatic insufficiency and liver fibrosis ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2010.03.018
更新日期:2010-07-01 00:00:00
abstract::Autofocusing is a postprocessing technique for motion correction, which optimizes an image quality metric against various trial motions. In this work, image metric maps, which are measures of image quality plotted as a function of in-plane 2-D trial translations, are systematically studied to develop improved autofocu...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.02.003
更新日期:2006-07-01 00:00:00
abstract:PURPOSE:To prospectively compare image quality and reliability of a non-contrast, self-navigated 3D whole-heart magnetic resonance angiography (MRA) sequence with contrast-enhanced computed tomography angiography (CTA) for sizing of thoracic aortic aneurysm (TAA). METHODS:Self-navigated 3D whole-heart 1.5 T MRA was pe...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2020.12.003
更新日期:2021-02-01 00:00:00
abstract::T2-weighted images are considered the most sensitive for lesion detection at high field; however, long imaging time is problematic. Accordingly, the authors compared four breath-hold T2 or T2* weighted sequences comprising T2*-weighted FLASH, T2*-weighted PSIF, T2-weighted rapid spin echo (RASE), and T2-weighted Turbo...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(92)90371-6
更新日期:1992-01-01 00:00:00
abstract:OBJECTIVE:Our purpose was to evaluate imaging findings of breast cancers according to the dominant stroma type by using kinetic curve analysis and model-based perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging. METHODS:From March 2011 to September 2011, 64 cancers in 64 patients were includ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2015.07.010
更新日期:2016-01-01 00:00:00
abstract::The nonhuman primate brain study provides important supplemental means for human brain exploration since the two species share close anatomical and functional similarities. MR diffusion tensor imaging (DTI) in human brain has revealed exquisite details of brain structures especially in the brain white matter. However,...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2008.07.004
更新日期:2009-04-01 00:00:00
abstract::We report initial NMR studies of continuous flow laser-polarized xenon gas, both in unrestricted tubing, and in a model porous media. The study uses Pulsed Gradient Spin Echo-based techniques in the gas-phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients....
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(03)00156-5
更新日期:2003-04-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Slice-encoding metal artifact corrections (SEMAC)-view-angle tilting (VAT) sequences have recently been used in clinical protocols to reduce metal artifacts in MR scans of patients with spinal instrumentation. The objective of this study was to compare the SEMAC-VAT sequence with the conventional...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.08.002
更新日期:2018-12-01 00:00:00
abstract:PURPOSE:This study aimed to further investigate the effects of agmatine on brain edema in the rats with middle cerebral artery occlusion (MCAO) injury using magnetic resonance imaging (MRI) monitoring and biochemical and histopathologic evaluation. MATERIALS AND METHODS:Following surgical induction of MCAO for 90min, ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2013.03.026
更新日期:2013-09-01 00:00:00
abstract::We recently directly examined the relationship between blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals and neural activity by simultaneously acquiring electrophysiological and fMRI data from monkeys in a 4.7-T vertical scanner (Logothetis NK, Pauls J, Augath MA, Trinath T, Oelt...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2007.03.015
更新日期:2007-07-01 00:00:00
abstract:PURPOSE:To analyze several histopathological features and their possible correlations with whole lesion histogram analysis derived from ADC maps in meningioma. MATERIALS AND METHODS:The retrospective study involved 36 patients with primary meningiomas. For every tumor, the following histogram analysis parameters of ap...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.05.009
更新日期:2018-09-01 00:00:00
abstract::Noninvasive functional studies on human spinal cord by means of magnetic resonance imaging (MRI) are gaining attention because of the promising applications in the study of healthy and injured central nervous system. The findings obtained are generally consistent with the anatomic knowledge based on invasive methods, ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章,评审
doi:10.1016/j.mri.2004.10.015
更新日期:2004-12-01 00:00:00
abstract::Contrast-enhanced 3D MR voiding urethrography (CE 3D MRVU) was performed on 5 healthy volunteers and 18 patients with urethral disease. After intravenous injection of 0.3 ml/kg gadolinium, the images of the three consecutive acquisitions of the 3D MRVU technique were obtained during voiding. The raw data were reconstr...
journal_title:Magnetic resonance imaging
pub_type: 临床试验,杂志文章
doi:10.1016/j.mri.2004.09.008
更新日期:2004-11-01 00:00:00
abstract::The role of susceptibility effects in the production of artifacts in chemical shift images generated by the selective excitation technique is discussed. The effects are demonstrated in images of phantom samples of agarose gels containing small air bubbles. The artifacts can lead to erroneous interpretations, in which ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(92)90022-r
更新日期:1992-01-01 00:00:00
abstract::The local determination of porosity is an extremely valuable target because of different applications in petrophysics. In fact, obtaining a reliable profile of porosity or saturations could considerably improve the evaluation of transport properties of porous media, especially if applied to multiphase flow test (i.e.,...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(96)00182-8
更新日期:1996-01-01 00:00:00
abstract::The subthalamic nucleus (STN) is one of the most common stimulation targets for treating Parkinson's disease using deep brain stimulation (DBS). This procedure requires precise placement of the stimulating electrode. Common practice of DBS implantation utilizes microelectrode recording to locate the sites with the cor...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.02.006
更新日期:2012-06-01 00:00:00
abstract::A four-channel Tic-Tac-Toe (TTT) transmit RF coil was designed and constructed for foot and ankle imaging at 7T MRI. Numerical simulations using an in-house developed FDTD package and experimental analyses using a homogenous phantom show an excellent agreement in terms of B1+ field distribution and s-parameters. Simul...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2017.09.005
更新日期:2018-01-01 00:00:00
abstract::We have developed an in vivo longitudinally detected ESR (LODESR) imaging system operating at 700 MHz based on a loop-gap resonator and a pair of saddle-type pickup coils. A good linear relationship between the LODESR signal intensity and the applied power in a range up to 15.8 W was obtained. The detection of LODESR ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(97)82763-4
更新日期:1997-01-01 00:00:00