Abstract:
:Mathematical models are required to estimate kinetic parameters of [1-(13)C] pyruvate-lactate interconversion from magnetic resonance spectroscopy data. One- or two-way exchange models utilizing a hypothetical approximation to the true arterial input function (AIF), (e.g. an ideal 'box-car' function) have been used previously. We present a method for direct measurement of the AIF in the rat. The hyperpolarized [1-(13)C] pyruvate signal was measured in arterial blood as it was continuously withdrawn through a small chamber. The measured signal was corrected for T1 relaxation of pyruvate, RF pulses and dispersion of blood in the chamber to allow for the estimation of the direct AIF. Using direct AIF, rather than the commonly used box-car AIF, provided realistic estimates of the rate constant of conversion of pyruvate to lactate, kpl, the rate constant of conversion of lactate to pyruvate klp, the clearance rate constant of pyruvate from blood to tissue, Kip, and the relaxation rate of lactate T1la. Since no lactate signal was present in blood, it was possible to use a simple precursor-product relationship, with the tumor tissue pyruvate time-course as the input for the lactate time-course. This provided a robust estimate of kpl, similar to that obtained using a directly measured AIF.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Kazan SM,Reynolds S,Kennerley A,Wholey E,Bluff JE,Berwick J,Cunningham VJ,Paley MN,Tozer GMdoi
10.1002/mrm.24546subject
Has Abstractpub_date
2013-10-01 00:00:00pages
943-53issue
4eissn
0740-3194issn
1522-2594journal_volume
70pub_type
杂志文章abstract::The sensitivity of diffusion-weighted MRI was compared to that of T2-weighted MRI following temporary middle cerebral artery occlusion (MCA-O) for 33 min followed by 4 h of reperfusion in rats. Diffusion-weighted spin-echo images using strong gradients (b value of 1413 s/mm2) demonstrated a significant increase in sig...
journal_title:Magnetic resonance in medicine
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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...
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journal_title:Magnetic resonance in medicine
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更新日期:2012-01-01 00:00:00
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更新日期:1997-06-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2017-01-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:1986-10-01 00:00:00
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更新日期:2012-11-01 00:00:00
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更新日期:2014-04-01 00:00:00