@article{ortmeier_macculloch_barskiy_kempf_myers_koerber_pravdivtsev_buckenmaier_theis_2024, title={SABRE-hyperpolarization dynamics of [1-13C]pyruvate monitored by in situ zero- to ultra-low field NMR}, volume={19}, ISSN={["2666-4410"]}, DOI={10.1016/j.jmro.2024.100149}, abstractNote={Hyperpolarized [1-13C]pyruvate is the leading metabolite used in the emerging field of hyperpolarization-enhanced MRI. Signal amplification by reversible exchange (SABRE) is a straight forward hyperpolarization method that has recently been shown to hyperpolarize [1-13C]pyruvate at low (microtesla and below) magnetic fields. Here, we show that commercial optical magnetometers with Rb-vapor media can be used to readily monitor the build-up and decay of the hyperpolarized MR signal. In addition, we measure ZULF-NMR spectra in various conditions, ranging from a J-coupling-dominated regime transitioning into a Zeeman-dominated regime when going from a sub-nT field to a µT field. The experimentally acquired spectra are matched well by numerical simulations.}, journal={JOURNAL OF MAGNETIC RESONANCE OPEN}, author={Ortmeier, Adam and MacCulloch, Keilian and Barskiy, Danila A. and Kempf, Nicolas and Myers, John Z. and Koerber, Rainer and Pravdivtsev, Andrey N. and Buckenmaier, Kai and Theis, Thomas}, year={2024}, month={Jun} }
 @article{macculloch_browning_bedoya_mcbride_abdulmojeed_dedesma_goodson_rosen_chekmenev_yen_et al._2023, title={Facile hyperpolarization chemistry for molecular imaging and metabolic tracking of [1-13C]pyruvate in vivo}, volume={16-17}, ISSN={["2666-4410"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85168097895&partnerID=MN8TOARS}, DOI={10.1016/j.jmro.2023.100129}, abstractNote={Hyperpolarization chemistry based on reversible exchange of parahydrogen, also known as Signal Amplification By Reversible Exchange (SABRE), is a particularly simple approach to attain high levels of nuclear spin hyperpolarization, which can enhance NMR and MRI signals by many orders of magnitude. SABRE has received significant attention in the scientific community since its inception because of its relative experimental simplicity and its broad applicability to a wide range of molecules, however in vivo detection of molecular probes hyperpolarized by SABRE has remained elusive. Here we describe a first demonstration of SABRE-hyperpolarized contrast detected in vivo, specifically using hyperpolarized [1-13C]pyruvate. Biocompatible formulations of hyperpolarized [1-13C]pyruvate in, both, methanol-water mixtures, and ethanol-water mixtures followed by dilution with saline and catalyst filtration were prepared and injected into healthy Sprague Dawley and Wistar rats. Effective hyperpolarization-catalyst removal was performed with silica filters without major losses in hyperpolarization. Metabolic conversion of pyruvate to lactate, alanine, and bicarbonate was detected in vivo. Pyruvate-hydrate was also observed as minor byproduct. Measurements were performed on the liver and kidney at 4.7 T via time-resolved spectroscopy and chemical-shift-resolved MRI. In addition, whole-body metabolic measurements were obtained using a cryogen-free 1.5 T MRI system, illustrating the utility of combining lower-cost MRI systems with simple, low-cost hyperpolarization chemistry to develop safe, and scalable molecular imaging.}, journal={JOURNAL OF MAGNETIC RESONANCE OPEN}, author={Macculloch, Keilian and Browning, Austin and Bedoya, David O. Guarin and Mcbride, Stephen J. and Abdulmojeed, Mustapha B. and Dedesma, Carlos and Goodson, Boyd M. and Rosen, Matthew S. and Chekmenev, Eduard Y. and Yen, Yi-Fen and et al.}, year={2023}, month={Dec} }
 @article{macculloch_browning_tomhon_lehmkuhl_chekmenev_theis_2023, title={Parahydrogen in Reversible Exchange Induces Long-Lived 15N Hyperpolarization of Anticancer Drugs Anastrozole and Letrozole}, volume={5}, ISSN={["1520-6882"]}, url={https://doi.org/10.1021/acs.analchem.2c04817}, DOI={10.1021/acs.analchem.2c04817}, abstractNote={Hyperpolarization modalities overcome the sensitivity limitations of NMR and unlock new applications. Signal amplification by reversible exchange (SABRE) is a particularly cheap, quick, and robust hyperpolarization modality. Here, we employ SABRE for simultaneous chemical exchange of parahydrogen and nitrile-containing anticancer drugs (letrozole or anastrozole) to enhance 15N polarization. Distinct substrates require unique optimal parameter sets, including temperature, magnetic field, or a shaped magnetic field profile. The fine tuning of these parameters for individual substrates is demonstrated here to maximize 15N polarization. After optimization, including the usage of pulsed μT fields, the 15N nuclei on common anticancer drugs, letrozole and anastrozole, can be polarized within 1-2 min. The hyperpolarization can exceed 10%, corresponding to 15N signal enhancement of over 280,000-fold at a clinically relevant magnetic field of 1 T. This sensitivity gain enables polarization studies at naturally abundant 15N enrichment level (0.4%). Moreover, the nitrile 15N sites enable long-lasting polarization storage with [15N]T1 over 9 min, enabling signal detection from a single hyperpolarization cycle for over 30 min.}, number={20}, journal={ANALYTICAL CHEMISTRY}, author={MacCulloch, Keilian and Browning, Austin and TomHon, Patrick and Lehmkuhl, Soeren and Chekmenev, Eduard Y. and Theis, Thomas}, year={2023}, month={May} }
 @article{browning_macculloch_tomhon_mandzhieva_chekmenev_goodson_lehmkuhl_theis_2023, title={Spin dynamics of [1,2-C-13(2)]pyruvate hyperpolarization by parahydrogen in reversible exchange at micro Tesla fields}, volume={25}, ISSN={["1463-9084"]}, url={https://doi.org/10.1039/D3CP00843F}, DOI={10.1039/d3cp00843f}, abstractNote={The spin dynamics during SABRE of [1,2-13C2]pyruvate are detailed. An analytical model and numerical simulations are used to understand the selective formation of hyperpolarized magnetization or singlet order on the 13C2-spin pair.}, number={24}, journal={PHYSICAL CHEMISTRY CHEMICAL PHYSICS}, author={Browning, Austin and Macculloch, Keilian and TomHon, Patrick and Mandzhieva, Iuliia and Chekmenev, Eduard Y. and Goodson, Boyd M. and Lehmkuhl, Soeren and Theis, Thomas}, year={2023}, month={Jun}, pages={16446–16458} }
 @article{macculloch_tomhon_browning_akeroyd_lehmkuhl_chekmenev_theis_2021, title={Hyperpolarization of common antifungal agents with SABRE}, volume={6}, ISSN={["1097-458X"]}, url={https://doi.org/10.1002/mrc.5187}, DOI={10.1002/mrc.5187}, abstractNote={Abstract}, number={12}, journal={MAGNETIC RESONANCE IN CHEMISTRY}, publisher={Wiley}, author={MacCulloch, Keilian and Tomhon, Patrick and Browning, Austin and Akeroyd, Evan and Lehmkuhl, Soren and Chekmenev, Eduard Y. and Theis, Thomas}, year={2021}, month={Jun} }