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Lothar R Schad - One of the best experts on this subject based on the ideXlab platform.

  • characterization of chronic active multiple sclerosis lesions with Sodium 23 na magnetic resonance imaging preliminary observations
    European Journal of Neurology, 2021
    Co-Authors: Philipp Eisele, Lothar R Schad, Matthias Kraemer, Andreas Dabringhaus, Claudia E Weber, Anne Ebert, Michael Platten, Achim Gass
    Abstract:

    BACKGROUND AND PURPOSE There has been an increasing interest in chronic active multiple sclerosis (MS) lesions as a new magnetic resonance imaging (MRI) marker of disease progression. Chronic active lesions are characterized by progressive tissue matrix damage, axonal loss and chronic inflammation. Sodium (23 Na) MRI provides a biochemical marker of cell integrity and tissue viability in a quantitative manner. The aim of this study was to investigate with 23 Na MRI tissue abnormalities in chronic active lesions as indicators of tissue destruction. METHODS To identify chronic active lesions, two 3D magnetization-prepared rapid acquisition gradient-echo datasets obtained 12 months apart were processed using the voxel-guided morphometry algorithm. Cross-sectional 23 Na MRI was performed during the 12-month follow-up period. Total Sodium concentration was calculated in chronic active lesions compared to shrinking, chronic stable and acute contrast-enhancing lesions. RESULTS Overall, 70 MS lesions (21 chronic active, 10 shrinking, 29 chronic stable lesions, 10 acute contrast-enhancing lesions) in 12 patients were included. Total Sodium concentration in chronic active lesions (49.57 ± 8.47 mM) was significantly higher than in shrinking (42.16 ± 3.9 mM; p = 0.03) and chronic stable lesions (39.92 ± 4.82 mM; p < 0.001). Chronic active lesions showed similar Sodium values compared to acute contrast-enhancing lesions (48.06 ± 6.65 mM; p = 0.97). No differences between shrinking and chronic stable lesions were observed (p = 0.89). CONCLUSION High Sodium values in chronic active MS lesions may be an indicator of ongoing inflammation and tissue damage.

  • cerebral Sodium 23 na magnetic resonance imaging in patients with migraine a case control study
    European Radiology, 2019
    Co-Authors: Melissa M Meyer, A Schmidt, Justus Benrath, Simon Konstandin, Lothar R Pilz, Michael G Harrington, Johannes Budjan, Mathias Meyer, Lothar R Schad
    Abstract:

    Evaluation of MRI-derived cerebral 23Na concentrations in patients with migraine in comparison with healthy controls. In this case-control study, 24 female migraine patients (mean age, 34 ± 11 years) were enrolled after evaluation of standardized questionnaires. Half (n = 12) of the cohort suffered from migraine, the other half was impaired by both migraine and tension-type headaches (TTH). The combined patient cohort was matched to 12 healthy female controls (mean age, 34 ± 11 years). All participants underwent a cerebral 23Na-magnetic resonance imaging examination at 3.0 T, which included a T1w MP-RAGE sequence and a 3D density-adapted, radial gradient echo sequence for 23Na imaging. Circular regions of interests were placed in predetermined anatomic regions: cerebrospinal fluid (CSF), gray and white matter, brain stem, and cerebellum. External 23Na reference phantoms were used to calculate the total 23Na tissue concentrations. Pearson’s correlation, Kendall Tau, and Wilcoxon rank sum test were used for statistical analysis. 23Na concentrations of all patients in the CSF were significantly higher than in healthy controls (p < 0.001). The CSF of both the migraine and mixed migraine/TTH group showed significantly increased Sodium concentrations compared to the control group (p = 0.007 and p < 0.001). Within the patient cohort, a positive correlation between pain level and TSC in the CSF (r = 0.62) could be observed. MRI-derived cerebral 23Na concentrations in the CSF of migraine patients were found to be statistically significantly higher than in healthy controls. • Cerebral Sodium MRI supports the theory of ionic imbalances and may aid in the challenging pathophysiologic understanding of migraine. • Case-control study shows significantly higher Sodium concentrations in cerebrospinal fluid of migraineurs. • Cerebral Sodium MRI may become a non-invasive imaging tool for drugs to modulate Sodium, and hence migraine, on a molecular level, and influence patient management.

  • apparent diffusion coefficient and Sodium concentration measurements in human prostate tissue via hydrogen 1 and Sodium 23 magnetic resonance imaging in a clinical setting at 3 t
    Investigative Radiology, 2012
    Co-Authors: Daniel Hausmann, Friedrich Wetterling, Frank G Zollner, Simon Konstandin, Stefan Haneder, Armin M Nagel, Dietmar Dinter, Stefan O Schonberg, Lothar R Schad
    Abstract:

    IntroductionMultiparametric magnetic resonance imaging (MRI) of the prostate involves morphologic and functional imaging techniques, which could potentially enable to distinguish between common benign prostate diseases, especially prostatitis and prostate cancer. The aim of this study was to determi

  • in vivo chlorine 35 Sodium 23 and proton magnetic resonance imaging of the rat brain
    NMR in Biomedicine, 2010
    Co-Authors: Stefan Kirsch, M Augath, David J Seiffge, Lothar Schilling, Lothar R Schad
    Abstract:

    In this study we demonstrate the feasibility of combined chlorine-35, Sodium-23 and proton magnetic resonance imaging (MRI) at 9.4 Tesla, and present the first in vivo chlorine-35 images obtained by means of MRI. With the experimental setup used in this study all measurements could be done in one session without changing the setup or moving the subject. The multinuclear measurement requires a total measurement time of 2 h and provides morphological (protons) and physiological (Sodium-23, chlorine-35) information in one scanning session. Chlorine-35, Sodium-23 and high resolution proton images were acquired from a phantom, a healthy rat and from a rat displaying a focal cerebral infarction. Compared to the healthy tissue a signal enhancement of a factor of 2.2 +/- 0.2 in the chlorine-35 and a factor of 2.9 +/- 0.6 in the Sodium-23 images is observed in the areas of infarction. Exemplary unlocalized measurement of the in vivo longitudinal and transversal relaxation time of chlorine-35 in a healthy rat showed multi-exponential behaviour. A biexponential fit revealed a fast and a slow relaxing component with T(1,a) = (1.7 +/- 0.4) ms, T(1,b) = (25.1 +/- 1.4) ms, amplitudes of A = 0.26 +/- 0.02, (1-A) = 0.74 +/- 0.02 and T(2,a) = (1.3 +/- 0.1) ms, T(2,b) = (11.8 +/- 1.1) ms, A = 0.64 +/- 0.02, (1-A) = 0.36 +/- 0.02. Combined proton, Sodium-23 and chlorine-35 MRI may provide a new approach for non-invasive studies of ionic regulatory processes under physiological and pathological conditions in vivo.

James T Grist - One of the best experts on this subject based on the ideXlab platform.

  • Sodium 23 na mri of the kidney basic concept
    Methods of Molecular Biology, 2021
    Co-Authors: James T Grist, Esben Sovso Hansen, Frank G Zollner, Christoffer Laustsen
    Abstract:

    The handling of Sodium by the renal system is a key indicator of renal function. Alterations in the corticomedullary distribution of Sodium are considered important indicators of pathology in renal diseases. The derangement of Sodium handling can be noninvasively imaged using Sodium magnetic resonance imaging (23Na MRI), with data analysis allowing for the assessment of the corticomedullary Sodium gradient. Here we introduce Sodium imaging, describe the existing methods, and give an overview of preclinical Sodium imaging applications to illustrate the utility and applicability of this technique for measuring renal Sodium handling.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

  • Sodium 23 na mri of the kidney experimental protocol
    Methods of Molecular Biology, 2021
    Co-Authors: James T Grist, Esben Sovso Hansen, Frank G Zollner, Christoffer Laustsen
    Abstract:

    Sodium handling is a key physiological hallmark of renal function. Alterations are generally considered a pathophysiologic event associated with kidney injury, with disturbances in the corticomedullary Sodium gradient being indicative of a number of conditions. This experimental protocol review describes the individual steps needed to perform 23Na MRI; allowing accurate monitoring of the renal Sodium distribution in a step-by-step experimental protocol for rodents.This chapter is based upon work from the PARENCHIMA COST Action, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.

  • analysis protocol for renal Sodium 23 na mr imaging
    Methods of Molecular Biology, 2021
    Co-Authors: James T Grist, Frank G Zollner, Esben Sovso Szocska Hansen, Christoffer Laustsen
    Abstract:

    The signal acquired in Sodium (23Na) MR imaging is proportional to the concentration of Sodium in a voxel, and it is possible to convert between the two using external calibration phantoms. Postprocessing, and subsequent analysis, of Sodium renal images is a simple task that can be performed with readily available software. Here we describe the process of conversion between Sodium signal and concentration, estimation of the corticomedullary Sodium gradient and the procedure used for quadrupolar relaxation analysis.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.

  • creating a clinical platform for carbon 13 studies using the Sodium 23 and proton resonances
    Magnetic Resonance in Medicine, 2020
    Co-Authors: James T Grist, Esben Sovso Szocska Hansen, Juan D Sanchezheredia, Mary A Mclean, Rasmus Stilling Tougaard, Frank Riemer, Rolf F Schulte, Joshua D Kaggie, Jan Henrik Ardenkjaerlarsen
    Abstract:

    Purpose Calibration of hyperpolarized 13 C-MRI is limited by the low signal from endogenous carbon-containing molecules and consequently requires 13 C-enriched external phantoms. This study investigated the feasibility of using either 23 Na-MRI or 1 H-MRI to calibrate the 13 C excitation. Methods Commercial 13 C-coils were used to estimate the transmit gain and center frequency for 13 C and 23 Na resonances. Simulations of the transmit B1 profile of a Helmholtz loop were performed. Noise correlation was measured for both nuclei. A retrospective analysis of human data assessing the use of the 1 H resonance to predict [1-13 C]pyruvate center frequency was also performed. In vivo experiments were undertaken in the lower limbs of 6 pigs following injection of hyperpolarized 13 C-pyruvate. Results The difference in center frequencies and transmit gain between tissue 23 Na and [1-13 C]pyruvate was reproducible, with a mean scale factor of 1.05179 ± 0.00001 and 10.4 ± 0.2 dB, respectively. Utilizing the 1 H water peak, it was possible to retrospectively predict the 13 C-pyruvate center frequency with a standard deviation of only 11 Hz sufficient for spectral-spatial excitation-based studies. Conclusion We demonstrate the feasibility of using the 23 Na and 1 H resonances to calibrate the 13 C transmit B1 using commercially available 13 C-coils. The method provides a simple approach for in vivo calibration and could improve clinical workflow.

Paul A Bottomley - One of the best experts on this subject based on the ideXlab platform.

  • tissue Sodium concentration in myocardial infarction in humans a quantitative 23na mr imaging study
    Radiology, 2008
    Co-Authors: Ronald Ouwerkerk, Paul A Bottomley, Meiyappan Solaiyappan, Amy E Spooner, Gordon F Tomaselli, Katherine C Wu, Robert G Weiss
    Abstract:

    Purpose: To prospectively determine whether the absolute tissue Sodium concentration (TSC) increases in myocardial infarctions (MIs) in humans and whether TSC is related to infarct size, infarct age, ventricular dysfunction, and/or electrophysiologic inducibility of ventricular arrhythmias. Materials and Methods: Delayed contrast material–enhanced 1.5-T hydrogen 1 (1H) magnetic resonance (MR) imaging was used to measure the size and location of nonacute MIs in 20 patients (18 men, two women; mean age, 63 years ± 9 [standard deviation]; age range, 48–82 years) examined at least 90 days after MI. End-systolic and end-diastolic volumes, ejection fraction, and left ventricle (LV) mass were measured with cine MR imaging. The TSC in normal, infarcted, and adjacent myocardial tissue was measured on Sodium 23 (23Na) MR images coregistered with delayed contrast-enhanced 1H MR images. Programmed electric stimulation to induce monomorphic ventricular tachycardia (MVT) was used to assess arrhythmic potential, and myo...

  • tissue Sodium concentration in human brain tumors as measured with 23na mr imaging
    Radiology, 2003
    Co-Authors: Ronald Ouwerkerk, Karen B Bleich, Joseph S Gillen, Martin G Pomper, Paul A Bottomley
    Abstract:

    PURPOSE: To use combined proton (1H) and Sodium 23 (23Na) magnetic resonance (MR) imaging to noninvasively quantify total tissue Sodium concentration and to determine if concentration is altered in malignant human brain tumors. MATERIALS AND METHODS: Absolute tissue Sodium concentration in malignant gliomas was measured on quantitative three-dimensional 23Na MR images with tissue identification from registered 1H MR images. Concentration was determined in gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and vitreous humor in 20 patients with pathologically proven malignant brain tumors (astrocytoma, n = 17; oligodendroglioma, n = 3) and in nine healthy volunteers. Sodium concentration in tumors and edema was determined from 23Na image signal intensities in regions that were contrast material enhanced on T1-weighted 1H images (tumors) or regions that were only hyperintense on fluid-attenuated inversion recovery (FLAIR) 1H images (edema). Sodium concentrations were measured noninvasively from 23Na images obtained with short echo times (0.4 msec) by using external saline solution phantoms for reference. Differences in mean Sodium concentration of all healthy tissue and lesions in patients were tested with a paired t test. Concentration in uninvolved tissues in patients was compared with that in the same tissue types in the volunteers with an independent samples two-tailed t test. RESULTS: Mean concentration (in millimoles per kilogram wet weight) was 61 +/- 8 (SD) for GM, 69 +/- 10 for WM, 135 +/- 10 for CSF, 113 +/- 14 for vitreous humor, 103 +/- 36 for tumor, 68 +/- 11 for unaffected contralateral tissue, and 98 +/- 12 for FLAIR hyperintense regions surrounding tumors. Significant differences (P <.002) in Sodium concentration were demonstrated by using a t test for both tumors and surrounding FLAIR hyperintense tissues versus GM, WM, CSF, and contralateral brain tissue. CONCLUSION: 23Na MR imaging with short echo times can be used to quantify absolute tissue Sodium concentration in patients with brain tumors and shows increased Sodium concentration in tumors relative to that in normal brain structures.

Ronald Ouwerkerk - One of the best experts on this subject based on the ideXlab platform.

  • tissue Sodium concentration in myocardial infarction in humans a quantitative 23na mr imaging study
    Radiology, 2008
    Co-Authors: Ronald Ouwerkerk, Paul A Bottomley, Meiyappan Solaiyappan, Amy E Spooner, Gordon F Tomaselli, Katherine C Wu, Robert G Weiss
    Abstract:

    Purpose: To prospectively determine whether the absolute tissue Sodium concentration (TSC) increases in myocardial infarctions (MIs) in humans and whether TSC is related to infarct size, infarct age, ventricular dysfunction, and/or electrophysiologic inducibility of ventricular arrhythmias. Materials and Methods: Delayed contrast material–enhanced 1.5-T hydrogen 1 (1H) magnetic resonance (MR) imaging was used to measure the size and location of nonacute MIs in 20 patients (18 men, two women; mean age, 63 years ± 9 [standard deviation]; age range, 48–82 years) examined at least 90 days after MI. End-systolic and end-diastolic volumes, ejection fraction, and left ventricle (LV) mass were measured with cine MR imaging. The TSC in normal, infarcted, and adjacent myocardial tissue was measured on Sodium 23 (23Na) MR images coregistered with delayed contrast-enhanced 1H MR images. Programmed electric stimulation to induce monomorphic ventricular tachycardia (MVT) was used to assess arrhythmic potential, and myo...

  • tissue Sodium concentration in human brain tumors as measured with 23na mr imaging
    Radiology, 2003
    Co-Authors: Ronald Ouwerkerk, Karen B Bleich, Joseph S Gillen, Martin G Pomper, Paul A Bottomley
    Abstract:

    PURPOSE: To use combined proton (1H) and Sodium 23 (23Na) magnetic resonance (MR) imaging to noninvasively quantify total tissue Sodium concentration and to determine if concentration is altered in malignant human brain tumors. MATERIALS AND METHODS: Absolute tissue Sodium concentration in malignant gliomas was measured on quantitative three-dimensional 23Na MR images with tissue identification from registered 1H MR images. Concentration was determined in gray matter (GM), white matter (WM), cerebrospinal fluid (CSF), and vitreous humor in 20 patients with pathologically proven malignant brain tumors (astrocytoma, n = 17; oligodendroglioma, n = 3) and in nine healthy volunteers. Sodium concentration in tumors and edema was determined from 23Na image signal intensities in regions that were contrast material enhanced on T1-weighted 1H images (tumors) or regions that were only hyperintense on fluid-attenuated inversion recovery (FLAIR) 1H images (edema). Sodium concentrations were measured noninvasively from 23Na images obtained with short echo times (0.4 msec) by using external saline solution phantoms for reference. Differences in mean Sodium concentration of all healthy tissue and lesions in patients were tested with a paired t test. Concentration in uninvolved tissues in patients was compared with that in the same tissue types in the volunteers with an independent samples two-tailed t test. RESULTS: Mean concentration (in millimoles per kilogram wet weight) was 61 +/- 8 (SD) for GM, 69 +/- 10 for WM, 135 +/- 10 for CSF, 113 +/- 14 for vitreous humor, 103 +/- 36 for tumor, 68 +/- 11 for unaffected contralateral tissue, and 98 +/- 12 for FLAIR hyperintense regions surrounding tumors. Significant differences (P <.002) in Sodium concentration were demonstrated by using a t test for both tumors and surrounding FLAIR hyperintense tissues versus GM, WM, CSF, and contralateral brain tissue. CONCLUSION: 23Na MR imaging with short echo times can be used to quantify absolute tissue Sodium concentration in patients with brain tumors and shows increased Sodium concentration in tumors relative to that in normal brain structures.

Hans J. Jakobsen - One of the best experts on this subject based on the ideXlab platform.