Technologies and Strategies for Metabolic and Molecular Imaging With Hyperpolarized MRI.

Conventional Magnetic Resonance Imaging (MRI) offers limited sensitivity for direct metabolic and molecular imaging using non-proton nuclei due to low thermal nuclear spin polarization. Hyperpolarization (HP) technologies increase nuclear spin polarization by several orders of magnitude, overcoming this limitation to enable in vivo studies of biochemistry and physiology. A growing body of literature has shown the value in HP technologies offering metabolic and functional information useful for a variety of clinical applications.

Development and optimization of human deuterium MR spectroscopic imaging at 3 T in the abdomen.

Purpose: To establish and optimize abdominal deuterium MR spectroscopic imaging in conjunction with orally administered H-labeled molecules.

Methods: A flexible transmit-receive surface coil was used to image naturally abundant deuterium signal in phantoms and healthy volunteers and after orally administered HO in a patient with a benign renal tumor (oncocytoma).

Results: Water and lipid peaks were fitted with high confidence from both unlocalized spectra and from voxels within the liver, kidney, and spleen on spectroscopic imaging.

K-Means Clustering of Hyperpolarised C-MRI Identifies Intratumoral Perfusion/Metabolism Mismatch in Renal Cell Carcinoma as the Best Predictor of the Highest Grade.

: Early and accurate grading of renal cell carcinoma (RCC) improves patient risk stratification and has implications for clinical management and mortality. However, current diagnostic approaches using imaging and renal mass biopsy have limited specificity and may lead to undergrading. : This study explored the use of hyperpolarised [1-C]pyruvate MRI (HP C-MRI) to identify the most aggressive areas within the tumour of patients with clear cell renal cell carcinoma (ccRCC) as a method to guide biopsy targeting and to reduce undergrading.

Multiarm, non-randomised, single-centre feasibility study-investigation of the differential biology between benign and malignant renal masses using advanced magnetic resonance imaging techniques (IBM-Renal): protocol.

Introduction: Localised renal masses are an increasing burden on healthcare due to the rising number of cases. However, conventional imaging cannot reliably distinguish between benign and malignant renal masses, and renal mass biopsies are unable to characterise the entirety of the tumour due to sampling error, which may lead to delayed treatment or overtreatment. There is an unmet clinical need to develop novel imaging techniques to characterise renal masses more accurately.

Deuterium Metabolic Imaging of Alzheimer Disease at 3-T Magnetic Field Strength: A Pilot Case-Control Study.

Background Impaired glucose metabolism is characteristic of several types of dementia, preceding cognitive symptoms and structural brain changes. Reduced glucose uptake in specific brain regions, detected using fluorine 18 (F) fluorodeoxyglucose (FDG) PET, is a valuable diagnostic marker in Alzheimer disease (AD). However, the use of F-FDG PET in clinical practice may be limited by equipment availability and high cost.

Radical-induced hetero-nuclear mixing and low-field C relaxation in solid pyruvic acid.

Radicals serve as a source of polarization in dynamic nuclear polarization, but may also act as polarization sink, in particular at low field. Additionally, if the couplings between the electron spins and different nuclear reservoirs are stronger than any of the reservoirs' couplings to the lattice, radicals can mediate hetero-nuclear polarization transfer. Here, we report radical-enhanced C relaxation in pyruvic acid doped with trityl.

Radical-Induced Low-Field H Relaxation in Solid Pyruvic Acid Doped with Trityl-OX063.

In dynamic nuclear polarization (DNP), radicals such as trityl provide a source for high nuclear spin polarization. Conversely, during the low-field transfer of hyperpolarized solids, the radicals' dipolar or Non-Zeeman reservoir may act as a powerful nuclear polarization sink. Here, we report the low-temperature proton spin relaxation in pyruvic acid doped with trityl, for fields from 5 mT to 2 T.

Deuterium metabolic imaging and hyperpolarized C-MRI of the normal human brain at clinical field strength reveals differential cerebral metabolism.

Deuterium metabolic imaging (DMI) and hyperpolarized C-pyruvate MRI (C-HPMRI) are two emerging methods for non-invasive and non-ionizing imaging of tissue metabolism. Imaging cerebral metabolism has potential applications in cancer, neurodegeneration, multiple sclerosis, traumatic brain injury, stroke, and inborn errors of metabolism. Here we directly compare these two non-invasive methods at 3 T for the first time in humans and show how they simultaneously probe both oxidative and non-oxidative metabolism.

Enabling Clinical Technologies for Hyperpolarized Xenon Magnetic Resonance Imaging and Spectroscopy.

Hyperpolarization is a technique that can increase nuclear spin polarization with the corresponding gains in nuclear magnetic resonance (NMR) signals by 4-8 orders of magnitude. When this process is applied to biologically relevant samples, the hyperpolarized molecules can be used as exogenous magnetic resonance imaging (MRI) contrast agents. A technique called spin-exchange optical pumping (SEOP) can be applied to hyperpolarize noble gases such as Xe.