B inhomogeneity correction of RARE MRI at low SNR: Quantitative in vivo F MRI of mouse neuroinflammation with a cryogenically-cooled transceive surface radiofrequency probe.

Purpose: Low SNR in fluorine-19 ( F) MRI benefits from cryogenically-cooled transceive surface RF probes (CRPs), but strong B inhomogeneities hinder quantification. Rapid acquisition with refocused echoes (RARE) is an SNR-efficient method for MRI of neuroinflammation with perfluorinated compounds but lacks an analytical signal intensity equation to retrospectively correct B inhomogeneity. Here, a workflow was proposed and validated to correct and quantify F-MR signals from the inflamed mouse brain using a F-CRP.

Pentafluorosulfanyl (SF) as a Superior F Magnetic Resonance Reporter Group: Signal Detection and Biological Activity of Teriflunomide Derivatives.

Fluorine (F) magnetic resonance imaging (MRI) is severely limited by a low signal-to noise ratio (SNR), and tapping it for F drug detection in vivo still poses a significant challenge. However, it bears the potential for label-free theranostic imaging. Recently, we detected the fluorinated dihydroorotate dehydrogenase (DHODH) inhibitor teriflunomide (TF) noninvasively in an animal model of multiple sclerosis (MS) using F MR spectroscopy (MRS).

Continuous diffusion spectrum computation for diffusion-weighted magnetic resonance imaging of the kidney tubule system.

Background: The use of rigid multi-exponential models (with predefined numbers of components) is common practice for diffusion-weighted MRI (DWI) analysis of the kidney. This approach may not accurately reflect renal microstructure, as the data are forced to conform to the assumptions of simplified models. This work examines the feasibility of less constrained, data-driven non-negative least squares (NNLS) continuum modelling for DWI of the kidney tubule system in simulations that include emulations of pathophysiological conditions.

Fluorine (F) MRI for Assessing Inflammatory Cells in the Kidney: Experimental Protocol.

Inflammation is one underlying contributing factor in the pathology of acute and chronic kidney disorders. Phagocytes such as monocytes, neutrophils and dendritic cells are considered to play a deleterious role in the progression of kidney disease but may also contribute to organ homeostasis. The kidney is a target of life-threatening autoimmune disorders such as the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV).

Functional Imaging Using Fluorine (F) MR Methods: Basic Concepts.

Kidney-associated pathologies would greatly benefit from noninvasive and robust methods that can objectively quantify changes in renal function. In the past years there has been a growing incentive to develop new applications for fluorine (F) MRI in biomedical research to study functional changes during disease states. F MRI represents an instrumental tool for the quantification of exogenous F substances in vivo.

Hardware Considerations for Preclinical Magnetic Resonance of the Kidney.

Magnetic resonance imaging (MRI) is a noninvasive imaging technology that offers unparalleled anatomical and functional detail, along with diagnostic sensitivity. MRI is suitable for longitudinal studies due to the lack of exposure to ionizing radiation. Before undertaking preclinical MRI investigations of the kidney, the appropriate MRI hardware should be carefully chosen to balance the competing demands of image quality, spatial resolution, and imaging speed, tailored to the specific scientific objectives of the investigation.

Preparation of Ex Vivo Rodent Phantoms for Developing, Testing, and Training MR Imaging of the Kidney and Other Organs.

Here we describe a simple and inexpensive protocol for preparing ex vivo rodent phantoms for use in MR imaging studies. The experimental animals are perfused and fixed with formaldehyde, and then wrapped with gauze and sealed with liquid latex. This yields a phantom that preserves all organs in situ, and which avoids the need to keep fixed animals and organs in containers that have dimensions very different from living animals.

detection of teriflunomide-derived fluorine signal during neuroinflammation using fluorine MR spectroscopy.

Magnetic resonance imaging (MRI) is indispensable for diagnosing neurological conditions such as multiple sclerosis (MS). MRI also supports decisions regarding the choice of disease-modifying drugs (DMDs). Determining tissue concentrations of DMDs has the potential to become an essential clinical tool for therapeutic drug monitoring (TDM).

Transient enlargement of brain ventricles during relapsing-remitting multiple sclerosis and experimental autoimmune encephalomyelitis.

The brain ventricles are part of the fluid compartments bridging the CNS with the periphery. Using MRI, we previously observed a pronounced increase in ventricle volume (VV) in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). Here, we examined VV changes in EAE and MS patients in longitudinal studies with frequent serial MRI scans.

B inhomogeneity correction of RARE MRI with transceive surface radiofrequency probes.

Purpose: The use of surface radiofrequency (RF) coils is common practice to boost sensitivity in (pre)clinical MRI. The number of transceive surface RF coils is rapidly growing due to the surge in cryogenically cooled RF technology and ultrahigh-field MRI. Consequently, there is an increasing need for effective correction of the excitation field ( ) inhomogeneity inherent in these coils.

Toward F magnetic resonance thermometry: spin-lattice and spin-spin-relaxation times and temperature dependence of fluorinated drugs at 9.4 T.

Objective: This study examines the influence of the environmental factor temperature on the F NMR characteristics of fluorinated compounds in phantom studies and in tissue.

Materials And Methods: F MR mapping and MR spectroscopy techniques were used to characterize the F NMR characteristics of perfluoro-crown ether (PFCE), isoflurane, teriflunomide, and flupentixol. T and T mapping were performed, while temperature in the samples was changed (T = 20-60 °C) and monitored using fiber optic measurements.

Fluorine-19 MRI at 21.1 T: enhanced spin-lattice relaxation of perfluoro-15-crown-5-ether and sensitivity as demonstrated in ex vivo murine neuroinflammation.

Objective: Fluorine MR would benefit greatly from enhancements in signal-to-noise ratio (SNR). This study examines the sensitivity gain of F MR that can be practically achieved when moving from 9.4 to 21.

Enhanced Fluorine-19 MRI Sensitivity using a Cryogenic Radiofrequency Probe: Technical Developments and Ex Vivo Demonstration in a Mouse Model of Neuroinflammation.

Neuroinflammation can be monitored using fluorine-19 (F)-containing nanoparticles and F MRI. Previously we studied neuroinflammation in experimental autoimmune encephalomyelitis (EAE) using room temperature (RT) F radiofrequency (RF) coils and low spatial resolution F MRI to overcome constraints in signal-to-noise ratio (SNR). This yielded an approximate localization of inflammatory lesions.