In the technique presented here, dubbed 'qMRS', we quantify change in

Purpose Glutamate weighted Chemical Exchange Saturation Transfer (GluCEST) MRI is a noninvasive technique for mapping parenchymal glutamate in the brain. Because of sensitivity to field (B 0 ) inhomogeneity, total acquisition time prolonged due repeated image acquisitions at several saturation offset frequencies, which can cause practical issues such as increased patient motions. GluCEST signal derived from small z‐spectrum difference, it often has low signal‐to‐noise‐ratio (SNR). We...

Regulation of insulin release and glucose homeostasis by pancreatic β-cells is dependent on the metabolism glucokinase (GK) influence that activity oxidative phosphorylation. Genetic alterations result in hyperactivity mitochondrial glutamate dehydrogenase (GDH-1) can cause hypoglycemia-hyperammonemia following high protein meals, but role GDH-1 remains poorly understood. strongly inhibited GTP, to near zero absence ADP, cooperatively activated ( n = 2.3) ADP. The dissociation constant for...

Purpose Two‐dimensional creatine CEST (2D‐CrCEST), with a slice thickness of 10‐20 mm and temporal resolution (τ Res ) about 30 seconds, has previously been shown to capture the creatine‐recovery kinetics in healthy controls patients abnormal creatine‐kinase following mild plantar flexion exercise. Since distribution disease burden may vary across muscle length for many musculoskeletal disorders, there is need increase coverage slice‐encoding direction. Here, we demonstrate feasibility...

Transcranial magnetic stimulation (TMS) is used in several FDA-approved treatments and, increasingly, to treat neurological disorders off-label uses. However, the mechanism by which TMS causes physiological change unclear, as are origins of response variability general population. Ideally, objective vivo biomarkers could shed light on these unknowns and eventually inform personalized interventions. Continuous theta-burst (cTBS) a form observed reduce motor evoked potentials (MEPs) for 60 min...

Glutamate‐weighted CEST (gluCEST) imaging is nearly unique in its ability to provide non‐invasive, spatially resolved measurements of glutamate vivo. In this article, we present an improved correction for B 1 inhomogeneity gluCEST images the human brain. Images were obtained on a Siemens 7.0 T Terra outfitted with single‐volume transmit/32‐channel receive phased array head coil. Numerical Bloch‐McConnell simulations, fitting and data processing performed using in‐house code written MATLAB...

A model for glucose sensing by pancreatic β-cells is developed and compared with the available experimental data. The brings together mathematical representations activities of sensor, glucokinase, oxidative phosphorylation. Glucokinase produces 6-phosphate (G-6-P) in an irreversible reaction that determines glycolytic flux. primary products glycolysis are NADH pyruvate. reoxidized reducing equivalents transferred to phosphorylation glycerol phosphate shuttle, some pyruvate oxidized...

Purpose The purpose of this study was to characterize the 1 H downfield MR spectrum from 8.0 10.0 ppm human skeletal muscle at 7 T and determine cross‐relaxation rates observed resonances. Methods We performed MRS in calf healthy volunteers. Single‐voxel collected using alternately selective or broadband inversion‐recovery sequences spectrally 90° E‐BURP RF pulse excitation centered 9.0 with bandwidth = 600 Hz (2.0 ppm). TIs 50–2500 ms. modeled recovery longitudinal magnetization three...

Purpose Ultra‐high field MR imaging lacks B 1 + inhomogeneity due to shorter RF wavelengths used at higher strengths compared human anatomy. CEST techniques tend be highly susceptible inhomogeneities a high and uniform being necessary create the endogenous contrast. High‐permittivity dielectric pads have seen increasing usage in their ability tailor spatial distribution of produced. The purpose this work is demonstrate that materials can improve glutamate weighted (gluCEST) 7T. Theory...

Membrane permeability is a desired property in drug design, but there have been difficulties quantifying the direct partitioning into native membranes. Platensimycin (PL) new promising antibiotic whose biosynthetic production costly. Six dialkylamine analogs of PL were synthesized with identical pharmacophores different side chains; five them found inactive. To address possibility that their activity limited by permeation step, we calculated polarity, measured surface and ability to insert...

Dielectric pads were used to improve the contrast of volumetric (3D) gluCEST via enhanced homogenization B 1 fields. Effective placement required additional coverage face due their physical size achieve saturated strength necessary recover signal from anterior portions brain. The origin gluCEST's need for high is discussed, and examples 3D images acquired with without use dielectric are provided repeatability in presence pad was determined.

Abstract Transcranial magnetic stimulation (TMS) is used in several FDA-approved treatments and, increasingly, to treat neurological disorders off-label uses. However, the mechanism by which TMS causes physiological change unclear, as are origins of response variability general population. Ideally, objective vivo biomarkers could shed light on these unknowns and eventually inform personalized interventions. Continuous theta burst (cTBS) a form has been observed reduce motor evoked potentials...

Deuterium metabolic imaging (DMI) has brought about a renewed interest in the application of 2 H-labeled substrates to map metabolism vivo, yet deuterium spectroscopy remains challenging. We have shown that deuterium-labeled glucose can be observed proton spectrum through reduction signal downstream metabolites technique called quantitative exchange label turnover MRS (qMRS). Here, we show prior knowledge fitting includes unlabeled as well forms glutamate used neural reliably with qMRS.

Nuclear Overhauser Effect (NOE) is an emerging technique to study mobile macromolecules such as lipids in the gray (GM) and white matter (WM) of brain. In this work, we optimized saturation pulse parameters NOE Magnetization Transfer Ratio (MTR) MRI investigated its reproducibility on a healthy human volunteer at 7 Telsa. We found that NOE-MTR GM WM regions brain was highly reproducible (COV<10%) over three year time span. addition, length 3 4 sec provided optimal contrast from both

Robust, reproducible methods are paramount in neuroimaging. This is a challenge for leading-edge and novel techniques at 7T MRI, such as glutamate-weighted chemical exchange saturation transfer (GluCEST). As such, our primary objective to move towards robust analytical pipeline GluCEST imaging data. Here we show, using python-based neuroimaging tools, the development of GluCEST-prep. GluCEST-prep incorporates common analysis steps—brain extraction, tissue segmentation,...

In the 1 H magnetic resonance (MR) spectrum of human muscle, non-exchangeable proton resonances have been observed at 8.0, 8.2 and 8.5 ppm. While relaxation rate enhancement these was previously observed, their cross-relaxation rates with bulk water not yet determined. Knowledge could improve design MR techniques or serve as a potential biomarker. We quantify using selective non-selective inversion-recovery downfield MRS 7T. ppm were significantly faster than 8.0 resonance.

Triplet-Triplet Annihilation (TTA) is a process in which two molecules their triplet spin states interact to produce one excited and ground state singlets. In traditional diffusive TTA systems, Pt or Pd porphyrins are typically used as 'sensitizers'. Upon excitation, followed by ultrafast intersystem crossing, they transfer the excitation energy of an 'annihilator' way collisional triplet-triplet (TTET), thus sensitizing annihilator states. Annihilator triplets undergo TTA, emission delayed...

May 7, 2019April 9, 2019Free AccessGlutamate-weighted CEST (GluCEST) MRI contrast at the site of transcranial magnetic stimulation is related to changes in motor evoked potentials (P3.1-019)John Medaglia, Abigail Cember, Ravi Nanga, Hari Hariharan, Brian Erickson, Apoorva Kelkar, Eric McConathey, Olufunsho Faseyitan, Roy Hamilton, H. Coslett, Mark Elliott, and Ravinder ReddyAuthors Info & AffiliationsApril 2019 issue92 (15_supplement)https://doi.org/10.1212/WNL.92.15_supplement.P3.1-019...