More Like this

1. Toward Lung Ventilation Imaging Using Hyperpolarized Diethyl Ether Gas Contrast Agent

   https://doi.org/10.1002/chem.202304071  

   Ariyasingha, Nuwandi M; Chowdhury, Md_Raduanul H; Samoilenko, Anna; Salnikov, Oleg G; Chukanov, Nikita V; Kovtunova, Larisa M; Bukhtiyarov, Valerii I; Shi, Zhongjie; Luo, Kehuan; Tan, Sidhartha; et al (May 2024, Chemistry – A European Journal)

   Abstract Hyperpolarized¹²⁹Xe gas was FDA‐approved as an inhalable contrast agent for magnetic resonance imaging of a wide range of pulmonary diseases in December 2022. Despite the remarkable success in clinical research settings, the widespread clinical translation of HP¹²⁹Xe gas faces two critical challenges: the high cost of the relatively low‐throughput hyperpolarization equipment and the lack of¹²⁹Xe imaging capability on clinical MRI scanners, which have narrow‐bandwidth electronics designed only for proton (¹H) imaging. To solve this translational grand challenge of gaseous hyperpolarized MRI contrast agents, here we demonstrate the utility of batch‐mode production of proton‐hyperpolarized diethyl ether gas via heterogeneous pairwise addition of parahydrogen to ethyl vinyl ether. An approximately 0.1‐liter bolus of hyperpolarized diethyl ether gas was produced in 1 second and injected in excised rabbit lungs. Lung ventilation imaging was performed using sub‐second 2D MRI with up to 2×2 mm²in‐plane resolution using a clinical 0.35 T MRI scanner without any modifications. This feasibility demonstration paves the way for the use of inhalable diethyl ether as a gaseous contrast agent for pulmonary MRI applications using any clinical MRI scanner. 

   more » « less
2. MRI4ALL : A Week‐Long Hackathon for the Development of an Open‐Source Ultra‐Low‐Field MRI System

   https://doi.org/10.1002/jmri.29771  

   Block, Kai Tobias; Zhang, Chengtong; Ciancia, Vito; Cooley, Clarissa; Geethanath, Sairam; Stockmann, Jason; Verghese, George; Alon, Leeor (March 2025, Journal of Magnetic Resonance Imaging)

   ABSTRACT The goal of the MRI4ALL hackathon, which took place in October 2023, was to develop a functional low‐field MRI scanner in just one week and to release all created source code and resources as open‐source packages. The event was attended by 52 participants from 16 institutions who assembled the scanner on the last day of the hackathon. The scanner's magnetic B₀field with a strength of 43 mT and a target field‐of‐view size of 11 cm³was created with a Halbach array made from 990 N40UH permanent magnets, held in place using 3D printed ring formers. Gradient coils were fabricated by gluing enameled copper wire onto 3D printed holders with imprinted wire patterns. A solenoid coil for RF transmission and reception was built by winding 20 turns of Litz wire around a 3D printed cylinder. A Red Pitaya FPGA prototyping board running the MaRCoS framework was used to control the scanner components, and a GPA‐FHDO amplifier board was used to drive the gradients. To simplify the scanner's operation, console software with an intuitive graphical user interface was developed in Python using the PyPulseq package for sequence calculations. Furthermore, the scanner was equipped with a cooling system, as well as options for passive and active shimming. After resolving several technical issues that arose during the assembly, the scanner is now able to acquire MR images with different sequences. While not suitable for real‐world clinical applications, it can be utilized for educational purposes or as a low‐cost prototyping platform. Moreover, it may serve as a reference design for future MRI development projects. All source code and resources are available on the project websitemri4all.org, allowing other groups to replicate the scanner. Evidence Leveln/a Technical EfficacyStage 1. 

   more » « less
3. An Fe( ii ) complex detects hydrogen peroxide with ¹ H and ¹⁹ F magnetic resonance imaging responses

   https://doi.org/10.1039/D5CC04066C  

   Karbalaei, Sana; Franke, Alicja; Zahl, Achim; Pokkuluri, P Raj; Beyers, Ronald J; Ivanović-Burmazović, Ivana; Goldsmith, Christian R (October 2025, Chemical Communications)

   A highly air- and water-stable Fe(ii) complex with a fluorinated ligand has a strong¹⁹F MRI signal but is a poorT₁-weighted¹H MRI contrast agent. Upon oxidation by H₂O₂, the¹⁹F MRI signal decays as the relaxivity for¹H MRI markedly improves. 

   more » « less
4. Rapid in situ carbon-13 hyperpolarization and imaging of acetate and pyruvate esters without external polarizer

   https://doi.org/10.1038/s42004-024-01316-x  

   Mohiuddin, Obaid; de_Maissin, Henri; Pravdivtsev, Andrey N; Brahms, Arne; Herzog, Marvin; Schröder, Leif; Chekmenev, Eduard Y; Herges, Rainer; Hövener, Jan-Bernd; Zaitsev, Maxim; et al (December 2024, Communications Chemistry)

   Abstract Hyperpolarized¹³C MRI visualizes real-time metabolic processes in vivo. In this study, we achieved high¹³C polarization in situ in the bore of an MRI system for precursor molecules of most widely employed hyperpolarized agents: [1-¹³C]acetate and [1-¹³C]pyruvate ethyl esters in their perdeuterated forms, enhancing hyperpolarization lifetimes, hyperpolarized toP_13C ≈ 28% at 80 mM concentration andP_13C ≈ 19% at 10 mM concentration, respectively. Using vinyl esters as unsaturated Parahydrogen-Induced Polarization via Side-Arm Hydrogenation (PHIP-SAH) precursors and our novel polarization setup, we achieved these hyperpolarization levels by fast side-arm hydrogenation in acetone-d₆at elevated temperatures (up to 90°C) and hydrogenation pressures (up to 32 bar). We optimized the hyperpolarization process, reducing it to under 10 s, and employed advanced pulse sequences to enhance the polarization transfer efficiency. The hyperpolarization system has a small footprint, allowing it to be positioned in the same magnet, where¹³C MRI is performed. We exemplified the utility of the design with sub-second in situ¹³C MRI of ethyl [1-¹³C]pyruvate-d₆. However, challenges remain in side-arm cleavage and purification in the MRI system to extract highly polarized aqueous agent solutions. Our results showcase efficient and rapid¹³C hyperpolarization of these metabolite precursors in an MRI system with minimal additional hardware, promising to enhance future throughput and access to hyperpolarized¹³C MRI. 

   more » « less
5. Iron( iii ) chelated paramagnetic polymeric nanoparticle formulation as a next-generation T ₁ -weighted MRI contrast agent

   https://doi.org/10.1039/d1ra05544e  

   Marasini, Ramesh; Rayamajhi, Sagar; Moreno-Sanchez, Anthony; Aryal, Santosh (September 2021, RSC Advances)

   Magnetic resonance imaging (MRI) is a routinely used imaging technique in medical diagnostics. To enhance the quality of MR images, contrast agents (CAs) are used, which account for nearly 40% of MRI exams in the clinic globally. The most used CAs are gadolinium-based CAs (GBCAs) but the use of GBCAs has been linked with metal-deposition in vital organs. Gadolinium deposition has been shown to be correlated with nephrogenic systemic fibrosis, a fibrosis of the skin and internal organs. Therefore, there is an unmet need for a new CA alternative to GBCAs for T 1 -weighted Ce-MRI. Herein, we designed paramagnetic ferric iron( iii ) ion-chelated poly(lactic- co -glycolic)acid nanoparticle formulation and routinely examined their application in Ce-MRI using clinical and ultra-high-field MRI scanners. Nanoparticles were monodispersed and highly stable at physiological pH over time with the hydrodynamic size of 130 ± 12 nm and polydispersity index of 0.231 ± 0.026. The T 1 -contrast efficacy of the nanoparticles was compared with commercial agent gadopentetate dimeglumine, called Magnevist®, in aqueous phantoms in vitro and then validated in vivo by visualizing an angiographic map in a clinical MRI scanner. Relaxivities of the nanoparticles in an aqueous environment were r 1 = 10.59 ± 0.32 mmol −1 s −1 and r 1 = 3.02 ± 0.14 mmol −1 s −1 at 3.0 T and 14.1 T measured at room temperature and pH 7.4, respectively. The clinically relevant magnetic field relaxivity is three times higher compared to the Magnevist®, a clinical GBCA, signifying its potential applicability in clinical settings. Moreover, iron is an endogenous metal with known metabolic safety, and the polymer and phospholipids used in the nanoconstruct are biodegradable and biocompatible components. These properties further put the proposed T 1 agent in a promising position in contrast-enhanced MRI of patients with any disease conditions. 

   more » « less