Parahydrogen-induced polarization and spin order transfer in ethyl pyruvate at high magnetic fields.

Nuclear magnetic resonance has experienced great advances in developing and translating hyperpolarization methods into procedures for fundamental and clinical studies. Here, we propose the use of a wide-bore NMR for large-scale (volume- and concentration-wise) production of hyperpolarized media using parahydrogen-induced polarization. We discuss the benefits of radio frequency-induced parahydrogen spin order transfer, we show that 100% polarization is theoretically expected for homogeneous B and B magnetic fields for a three-spin system.

Through-Space Multinuclear Magnetic Resonance Signal Enhancement Induced by Parahydrogen and Radiofrequency Amplification by Stimulated Emission of Radiation.

Hyperpolarized (, polarized far beyond the thermal equilibrium) nuclear spins can result in the radiofrequency amplification by stimulated emission of radiation (RASER) effect. Here, we show the utility of RASER to amplify nuclear magnetic resonance (NMR) signals of solute and solvent molecules in the liquid state. Specifically, parahydrogen-induced RASER was used to spontaneously enhance nuclear spin polarization of protons and heteronuclei (here F and P) in a wide range of molecules.

[Hyperpolarized C magnetic resonance imaging-a window into metabolism : High-resolution images of human metabolism].

Clinical Issue: Despite being one of the main pillars of modern diagnostics, magnetic resonance imaging (MRI) uses only a tiny fraction of its potential: no more than a millionth of all nuclear spins contribute to the MRI signal. In order to increase this fraction, called polarization, MRI scanners with stronger magnetic fields are being developed. However, even the most modern scanners do not exploit the potential of MRI.

Synthesis of C and H Labeled Vinyl Pyruvate and Hyperpolarization of Pyruvate.

The hyperpolarization of nuclear spins has enabled unique applications in chemistry, biophysics, and particularly metabolic imaging. Parahydrogen-induced polarization (PHIP) offers a fast and cost-efficient way of hyperpolarization. Nevertheless, PHIP lags behind dynamic nuclear polarization (DNP), which is already being evaluated in clinical studies.

[Noninvasive functional lung imaging with hyperpolarized xenon : Breakthrough for diagnostics?].

Background: Magnetic resonance imaging (MRI) is a noninvasive technique that provides excellent contrast for soft tissue organs. However, due to the low density of protons and many air-tissue junctions, its application in the lung is limited. Thus, X‑ray-based methods are often used here (with the well-known disadvantages of ionizing radiation).

Influence of Spatial Resolution and Compressed SENSE Acceleration Factor on Flow Quantification with 4D Flow MRI at 3 Tesla.

Four-dimensional (4D) flow MRI allows quantifying flow in blood vessels-non invasively and in vivo. The clinical use of 4D flow MRI in small vessels, however, is hampered by long examination times and limited spatial resolution. Compressed SENSE (CS-SENSE) is a technique that can accelerate 4D flow dramatically.

Dynamic monitoring of fracture healing process in response to magnesium implant with multimodal imaging: pilot longitudinal study in a rat external fixation model.

Rodent models are commonly used in pre-clinical research of magnesium (Mg)-based and other types of biomaterials for fracture treatment. Most studies selected unstable fixation methods, and there is a lack of multimodal longitudinal monitoring of bone healing. The purpose of this study is to develop a rat femoral fracture model stabilized by external fixation with intra-medullary Mg implant, and to investigate the dynamic bone union process with several imaging techniques offering complementing insights into the process.

Frequency-Selective Manipulations of Spins allow Effective and Robust Transfer of Spin Order from Parahydrogen to Heteronuclei in Weakly-Coupled Spin Systems.

We present a selectively pulsed (SP) generation of sequences to transfer the spin order of parahydrogen (pH ) to heteronuclei in weakly coupled spin systems. We analyze and discuss the mechanism and efficiency of SP spin order transfer (SOT) and derive sequence parameters. These new sequences are most promising for the hyperpolarization of molecules at high magnetic fields.

Selective excitation of hydrogen doubles the yield and improves the robustness of parahydrogen-induced polarization of low-γ nuclei.

We describe a new method for pulsed spin order transfer of parahydrogen-induced polarization (PHIP) that enables high polarization in incompletely H-labeled molecules by exciting only the desired protons in a frequency-selective manner. This way, the effect of selected -couplings is suspended. Experimentally 1.

Coherent Evolution of Signal Amplification by Reversible Exchange in Two Alternating Fields (alt-SABRE).

Parahydrogen (pH ) is a convenient and cost-efficient source of spin order to enhance the magnetic resonance signal. Previous work showed that transient interaction of pH with a metal organic complex in a signal amplification by reversible exchange (SABRE) experiment enabled more than 10 % polarization for some N molecules. Here, we analyzed a variant of SABRE, consisting of a magnetic field alternating between a low field of ∼1 μT, where polarization transfer is expected to take place, and a higher field >50 μT (alt-SABRE).

Luminal enhancement in intracranial aneurysms: fact or feature?-A quantitative multimodal flow analysis.

Purpose: Intracranial aneurysm (IA) wall enhancement on post-contrast vessel wall magnetic resonance imaging (VW-MRI) is assumed to be a biomarker for vessel wall inflammation and aneurysm instability. However, the exact factors contributing to enhancement are not yet clarified. This study investigates the relationship between luminal enhancement and intra-aneurysmal flow behaviour to assess the suitability of VW-MRI as a surrogate method for determining quantitative and qualitative flow behaviour in the aneurysm sac.

Parahydrogen-Induced Polarization Relayed via Proton Exchange.

The hyperpolarization of nuclear spins is a game-changing technology that enables hitherto inaccessible applications for magnetic resonance in chemistry and biomedicine. Despite significant advances and discoveries in the past, however, the quest to establish efficient and effective hyperpolarization methods continues. Here, we describe a new method that combines the advantages of direct parahydrogenation, high polarization (), fast reaction, and low cost with the broad applicability of polarization transfer via proton exchange.

Imaging Inflammation - From Whole Body Imaging to Cellular Resolution.

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented.

Selective excitation doubles the transfer of parahydrogen-induced polarization to heteronuclei.

In this work, we present a new pulse sequence to transform the spin order added to a molecule after the pairwise addition of parahydrogen into 13C polarization. Using a selective 90° preparation instead of a non-selective 45° excitation, the new variant performed twice as well as previous implementations in both simulations and experiments, exemplified with hyperpolarized ethyl acetate. This concept is expected to extend to other nuclei and other spin order transfer schemes that use non-selective excitation.

Metallic Implants in MRI - Hazards and Imaging Artifacts.

Background:  Magnetic resonance imaging (MRI) is an examination method for noninvasive soft tissue imaging without the use of ionizing radiation. Metallic implants, however, may pose a risk for the patient and often result in imaging artifacts. Due to the increasing number of implants, reducing these artifacts has become an important goal.

Acid-Sphingomyelinase Triggered Fluorescently Labeled Sphingomyelin Containing Liposomes in Tumor Diagnosis after Radiation-Induced Stress.

In liposomal delivery, a big question is how to release the loaded material into the correct place. Here, we will test the targeting and release abilities of our sphingomyelin-consisting liposome. A change in release parameters can be observed when sphingomyelin-containing liposome is treated with sphingomyelinase enzyme.

Pseudo-Enhancement in Intracranial Aneurysms on Black-Blood MRI: Effects of Flow Rate, Spatial Resolution, and Additional Flow Suppression.

Background: Vessel-wall enhancement (VWE) on black-blood MRI (BB MRI) has been proposed as an imaging marker for a higher risk of rupture and associated with wall inflammation. Whether VWE is causally linked to inflammation or rather induced by flow phenomena has been a subject of debate.

Purpose: To study the effects of slow flow, spatial resolution, and motion-sensitized driven equilibrium (MSDE) preparation on signal intensities in BB MRI of patient-specific aneurysm flow models.

Parahydrogen-Induced Polarization of Amino Acids.

Nuclear magnetic resonance (NMR) has become a universal method for biochemical and biomedical studies, including metabolomics, proteomics, and magnetic resonance imaging (MRI). By increasing the signal of selected molecules, the hyperpolarization of nuclear spin has expanded the reach of NMR and MRI even further (e.g.

Open-source, partially 3D-printed, high-pressure (50-bar) liquid-nitrogen-cooled parahydrogen generator.

The signal of magnetic resonance imaging (MRI) can be enhanced by several orders of magnitude using hyperpolarization. In comparison to a broadly used dynamic nuclear polarization (DNP) technique that is already used in clinical trials, the parahydrogen (H-based hyperpolarization approaches are less cost-intensive, are scalable, and offer high throughput. However, a H generator is necessary.

Catalytic Hydrogenation of Trivinyl Orthoacetate: Mechanisms Elucidated by Parahydrogen Induced Polarization.

Parahydrogen (pH ) induced polarization (PHIP) is a unique method that is used in analytical chemistry to elucidate catalytic hydrogenation pathways and to increase the signal of small metabolites in MRI and NMR. PHIP is based on adding or exchanging at least one pH molecule with a target molecule. Thus, the spin order available for hyperpolarization is often limited to that of one pH molecule.

Comparison of photoacoustic and fluorescence tomography for the imaging of ICG-labelled liposomes in the medullary cavity in mice.

Few reports quantitatively compare the performance of photoacoustic tomography (PAT) fluorescence molecular tomography (FMT) . We compared both modalities for the detection of signals from injected ICG liposomes in the tibial medullary space of 10 BALB/c mice and . Signals significantly correlated between modalities (R² = 0.