Abstract:
:Uncertainty regarding the intracellular/extracellular distribution of inorganic phosphate (P(i)) in tumors has raised concerns that pH calculated from the tumor P(i) chemical shift may not accurately represent the intracellular pH (pHin). This issue was addressed in subcutaneously transplanted murine radiation induced fibrosarcoma-1 by directly comparing pH measured via P(i) with pH measured via the in situ generated intracellular xenometabolite 2-deoxyglucose-6-phosphate (2DG6P). In 131 comparative measurements employing eight tumor-bearing mice under both control and hyperglycemic conditions (the latter to extend the range of tumor pH examined), the pH as derived from either 2DG6P or P(i) showed only a small, but statistically significant, difference (0.07 +/- 0.11 SD; P = 0.0001). Scatter in the comparative analysis over the pH range examined (ca. 5.5-7.5) was not uniform. Above pH 6.6, 2DG6P indicated a pH lower than that of P(i) by 0.088 +/- 0.105 SD (n = 107, P = 0.0001); below pH 6.6, 2DG6P indicated a pH essentially identical to and not statistically different from that of P(i) (mean difference 0.003 +/- 0.128 SD (n = 24, P = 0.92)). Evidence is presented in support of this differential arising from a systematic measurement error due to peak overlap between 2DG6P and endogenous phosphomonoester species. These results support the use of P(i) as a tumor 31P NMR pHin indicator, at least in RIF-1 tumors under control and hyperglycemic conditions.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Soto GE,Zhu Z,Evelhoch JL,Ackerman JJdoi
10.1002/mrm.1910360508subject
Has Abstractpub_date
1996-11-01 00:00:00pages
698-704issue
5eissn
0740-3194issn
1522-2594journal_volume
36pub_type
杂志文章abstract:PURPOSE:Nicotinamide adenine dinucleotide (NAD), in oxidized (NAD(+) ) or reduced (NADH) form, plays key roles in cellular metabolism. Intracellular NAD(+) /NADH ratio represents the cellular redox state; however, it is difficult to measure in vivo. We report here a novel in vivo (31) P MRS method for noninvasive measu...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24859
更新日期:2014-06-01 00:00:00
abstract::The magnetization subtraction technique (MS), which is equivalent to the inversion recovery technique in strong magnetic fields, has been implemented in dynamic nuclear polarization-enhanced magnetic resonance imaging (DNPI). The general theoretical basis of the MS method, which can be applied to DNPI or to prepolariz...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910350316
更新日期:1996-03-01 00:00:00
abstract:PURPOSE:Lung pO2 mapping with (3)He MRI assumes that the sources of signal decay with time during a breath-hold are radiofrequency depolarization and oxygen-dependent T1 relaxation, but the method is sensitive to other sources of spatio-temporal signal change such as diffusion. The purpose of this work was to assess th...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24779
更新日期:2014-03-01 00:00:00
abstract:PURPOSE:This assesses the potential of measuring lactate in the human brain using three non-editing MRS methods at 7T and compares the accuracy and precision of the methods. METHODS:1 H MRS data were measured in the right dorsolateral prefrontal cortex using a semi-adiabatic spin-echo full-intensity acquired localized...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.28066
更新日期:2020-06-01 00:00:00
abstract::Human brain white matter exhibits an uncommonly strong dispersion of 1/T1 at high fields. An additional relaxation pathway via the myelin lipids, which are not directly visible to medical NMR due to their fast T2 decay, is proposed. Relaxation dispersion data are successfully analyzed on the basis of this model. ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910090319
更新日期:1989-03-01 00:00:00
abstract::In the pulsed arterial spin labeling (ASL) techniques EPISTAR, PICORE, and FAIR, subtraction of two images in which inflowing blood is first tagged and then not tagged yields a qualitative map of perfusion. An important reason this map is not quantitative is that there is a spatially varying delay in the transit of bl...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910390506
更新日期:1998-05-01 00:00:00
abstract:PURPOSE:To assess the feasibility of using dissolved hyperpolarized xenon-129 (129 Xe) MRI to study renal physiology in humans at 3 T. METHODS:Using a flexible transceiver RF coil, dynamic and spatially resolved 129 Xe spectroscopy was performed in the abdomen after inhalation of hyperpolarized 129 Xe gas with 3 healt...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27923
更新日期:2020-01-01 00:00:00
abstract::Rapid MR imaging using the stimulated echo acquisition mode (STEAM) technique yields single-shot images without any sensitivity to resonance offset effects. However, the absence of susceptibility-induced signal voids or geometric distortions is at the expense of a somewhat lower signal-to-noise ratio than EPI. As a co...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21401
更新日期:2008-04-01 00:00:00
abstract::Specific absorption rate management and excitation fidelity are key aspects of radiofrequency pulse design for parallel transmission at ultra-high magnetic field strength. The design of radiofrequency pulses for multiple channels is often based on the solution of regularized least-squares optimization problems for whi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23004
更新日期:2012-01-01 00:00:00
abstract:PURPOSE:To optimize 3D radial ultrashort echo time MRI for high resolution whole-lung imaging. METHODS:3D radial ultrashort echo time was implemented on a 3T scanner to investigate the effects of: (1) limited field-of-view excitation, (2) variable density readouts, and (3) radial oversampling. Improvements in noise pe...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24570
更新日期:2013-11-01 00:00:00
abstract:PURPOSE:The optic nerve (ON) represents the sole pathway between the eyes and brain; consequently, diseases of the ON can have dramatic effects on vision. However, quantitative magnetization transfer (qMT) applications in the ON have been limited to ex vivo studies, in part because of the fatty connective tissue that s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26164
更新日期:2017-02-01 00:00:00
abstract::MR oximetry requires a T2 measurement that is accurate within 5% in vivo. Simple methods are susceptible to signal loss and tend to underestimate T2. Current methods utilize RF pulses or RF cycling patterns that prevent signal loss at each data acquisition. However, using these methods with imperfect pulses, T2 tends ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380512
更新日期:1997-11-01 00:00:00
abstract::Keyhole acquisition techniques have been used to reduce image acquisition times primarily in contrast agent studies and via simulation in interventional MRI procedures. More recent simulations have suggested that improved definition of an interventional device [e.g., biopsy needles, radio frequency (RF) electrodes] co...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199909)42:3<554::aid-mrm18
更新日期:1999-09-01 00:00:00
abstract::Gradient-recalled echo-planar (T2*-weighted) imaging was used to noninvasively monitor regional blood oxygenation state changes in real time during transient episodes of focal ischemia in cat brain. Varying ischemic intervals (12 s to 30 min) were caused by middle cerebral artery occlusion. A rapid signal drop was not...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910270220
更新日期:1992-10-01 00:00:00
abstract::Intraplaque hemorrhage in atherosclerotic plaques has been associated with accelerated plaque growth as well as exacerbation of clinical symptoms. The identification of intraplaque hemorrhage using magnetic resonance imaging primarily relies on the detection of methemoglobin on T(1) weighted images. Current techniques...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22539
更新日期:2010-11-01 00:00:00
abstract:PURPOSE:To design low peak and integrated power simultaneous multislice excitation radiofrequency pulses with transmit field inhomogeneity compensation in high field MRI. THEORY AND METHODS:The "interleaved greedy and local optimization" algorithm for small-tip-angle spokes pulses is extended to design multiband (MB) ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25455
更新日期:2015-09-01 00:00:00
abstract::The effect on lung ventilation of bronchoconstriction induced by serotonin (intravenous injection of 50 microg/kg of serotonin) was imaged using a hyperpolarized (3)He MR ventilation protocol in spontaneously breathing rats. Lung function maps assessing airflow obstruction, a key feature in clinical pneumology, were d...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22391
更新日期:2010-06-01 00:00:00
abstract:PURPOSE:High angular resolution diffusion imaging (HARDI) is a well-established method to help reveal the architecture of nerve bundles, but long scan times and geometric distortions inherent to echo planar imaging (EPI) have limited its integration into clinical protocols. METHODS:A fast imaging method is proposed he...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26163
更新日期:2017-02-01 00:00:00
abstract::Quantification of peak velocity is important in the assessment of stenotic flow jets in patients with congenital heart disease. Phase-contrast magnetic resonance underestimates peak velocities. Hence, clinically Doppler ultrasound is used as the reference standard for assessing stenoses. It is possible to accurately m...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24293
更新日期:2012-06-01 00:00:00
abstract::Noninvasive investigation of aldose reductase activities in rat testis was performed using 3-fluoro-3-deoxy-D-glucose (3-FDG) and nuclear magnetic resonance (NMR) spectroscopy/imaging. Quantitative determination of testis aldose reductase activities, expressed as the sorbitol index, showed a value similar to that of b...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910290417
更新日期:1993-04-01 00:00:00
abstract::The intra-individual and inter-individual variations of the global N-acetylaspartate (NAA) concentration were measured in a cohort of five 42+/-5 year-old normal females. The total NAA signal from the whole head was obtained with non-localized non-echo proton spectroscopy (1H-MRS) and converted into absolute mole amou...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
doi:10.1002/mrm.1910400506
更新日期:1998-11-01 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::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:PURPOSE:To design, evaluate, and apply a bow tie antenna transceiver radiofrequency (RF) coil array tailored for cardiac MRI at 7.0 Tesla (T). METHODS:The radiofrequency (RF) coil array comprises 16 building blocks each containing a bow tie shaped λ/2-dipole antenna. Numerical simulations were used for transmission fi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25840
更新日期:2016-06-01 00:00:00
abstract:PURPOSE:Diffusion-weighted imaging (DWI) and 18 F-fluorodeoxyglucose-positron emission tomography (18 F-FDG-PET) independently correlate with malignancy in breast cancer, but the relationship between their structural and metabolic metrics is not completely understood. This study spatially correlates diffusion, perfusio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26505
更新日期:2017-09-01 00:00:00
abstract::Choline-containing compounds (CCCs) are elevated in breast cancer, and detected in vivo by the (1)H MRS total choline (tCho) resonance (3.25 ppm) and the (31)P MRS phosphomonoester (PME) resonance (3.8 ppm). Both the tCho and PME resonances decrease early after initiation of successful therapy. The single major compon...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21333
更新日期:2007-08-01 00:00:00
abstract::Spiral k-space magnetic resonance spectroscopic imaging (MRSI) requires high performance from gradient hardware systems. During the readout phase, oscillating gradients are continuously played out, which can cause undesired effects. These effects on the quality of SI data are non-intuitive because of their time-varyin...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20928
更新日期:2006-07-01 00:00:00
abstract:PURPOSE:To develop a fast protocol for measuring T1 values in the internal carotid artery (ICA), to validate this technique with in vitro measurements, and to evaluate its reproducibility. METHODS:A modified Look-Locker sequence was optimized to enable rapid determination of T1 in the ICA at 3T. T1 values from the ICA...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26325
更新日期:2017-06-01 00:00:00
abstract::Consideration of spatially variable noise fields is becoming increasingly necessary in MRI given recent innovations in artifact identification and statistically driven image processing. Fast imaging methods enable study of difficult anatomical targets and improve image quality but also increase the spatial variability...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22013
更新日期:2009-08-01 00:00:00
abstract:PURPOSE:To improve signal-to-noise ratio (SNR) for high-resolution spectroscopic imaging using a subspace-based technique known as SPectroscopic Imaging by exploiting spatiospectral CorrElation (SPICE). METHODS:The proposed method is based on a union-of-subspaces model of MRSI signals, which exploits the partial separ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.26130
更新日期:2017-02-01 00:00:00