Mehrdad Pourfathi

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Until recently, molecular imaging using magnetic resonance (MR) has been limited by the modality's low sensitivity, especially with non-proton nuclei. The advent of hyperpolarized (HP) MR overcomes this limitation by substantially enhancing the signal of certain biologically important probes through a process known as external nuclear polarization, enabling(More)
PURPOSE To produce hyperpolarized bicarbonate indirectly via chemical reaction from a hyperpolarized precursor and utilize it for the simultaneous regional measurement of metabolism and pH. METHODS Alpha keto carboxylic acids are first hyperpolarized by dissolution dynamic nuclear polarization (DNP). These precursor molecules are rapidly reacted with(More)
Dynamic nuclear polarization (DNP) of (15)N2O, known for its long-lived singlet-state order at low magnetic field, is demonstrated in organic solvent/trityl mixtures at ∼1.5 K and 5 T. Both (15)N polarization and intermolecular dipolar broadening are strongly affected by the sample's thermal history, indicating spontaneous formation of N2O clusters. In situ(More)
Metabolic activity in the lung is known to change in response to external insults, inflammation, and cancer. We report measurements of metabolism in the isolated, perfused rat lung of healthy controls and in diseased lungs undergoing acute inflammation using hyperpolarized 1-(13) C-labeled pyruvate. The overall apparent activity of lactate dehydrogenase is(More)
PURPOSE To investigate pulmonary metabolic alterations during progression of acute lung injury. METHODS Using hyperpolarized [1-13 C] pyruvate imaging, we measured pulmonary lactate and pyruvate in 15 ventilated rats 1, 2, and 4 h after initiation of mechanical ventilation. Lung compliance was used as a marker for injury progression. 5 untreated rats were(More)
During dynamic nuclear polarization (DNP) at 1.5 K and 5 T, (129)Xe nuclear magnetic resonance (NMR) spectra of a homogeneous xenon/1-propanol/trityl-radical solid mixture exhibit a single peak, broadened by (1)H neighbors. A second peak appears upon annealing for several hours at 125 K. Its characteristic width and chemical shift indicate the presence of(More)
Ex vivo lung perfusion (EVLP) has recently shown promise as a means of more accurately gauging the health of lung grafts and improving graft performance post-transplant. However, reperfusion of ischemic lung promotes the depletion of high-energy compounds and a progressive loss of normal mitochondrial function, and it remains unclear how and to what extent(More)
Earlier Dynamic Nuclear Polarization (DNP) experiments with frozen xenon/1-propanol/trityl mixtures have demonstrated spontaneous formation of pure xenon clusters above 120 K, enabling spectrally-resolved real-time measurements of (129)Xe nuclear magnetization in the clusters and in the surrounding radical-rich matrix. A spin-diffusion bottleneck was(More)
Intra-uterine fetal ECG monitoring is critical for identical twin gestations because of the increased risk for cardiac defects. Ultrasound echocardiography is important clinically but it does not provide entirely conclusive information pertaining to the fetal cardiac conduction system. On the other hand, fetal electrocardiography can be obtained indirectly(More)
BACKGROUND Clinically translatable hyperpolarized (HP) (13)C-NMR can probe in vivo enzymatic reactions, e.g., lactate dehydrogenase (LDH)-catalyzed reaction by injecting HP (13)C-pyruvate into the subject, which is converted to (13)C labeled lactate by the enzyme. Parameters such as (13)C-lactate signals and lactate-to-pyruvate signal ratio are commonly(More)