TY - JOUR A1 - Winter, Patrick A1 - Kampf, Thomas A1 - Helluy, Xavier A1 - Gutjahr, Fabian T. A1 - Meyer, Cord B. A1 - Rommel, Eberhard A1 - Bauer, Wolfgang R. A1 - Jakob, Peter M. A1 - Herold, Volker T1 - Fast retrospectively triggered local pulse-wave velocity measurements in mice with CMR-microscopy using a radial trajectory JF - Journal of Cardiovascular Magnetic Resonance N2 - Background The aortic pulse-wave velocity (PWV) is an important indicator of cardiovascular risk. In recent studies MRI methods have been developed to measure this parameter noninvasively in mice. Present techniques require additional hardware for cardiac and respiratory gating. In this work a robust self-gated measurement of the local PWV in mice without the need of triggering probes is proposed. Methods The local PWV of 6-months-old wild-type C57BL/6J mice (n=6) was measured in the abdominal aorta with a retrospectively triggered radial Phase Contrast (PC) MR sequence using the flow-area (QA) method. A navigator signal was extracted from the CMR data of highly asymmetric radial projections with short repetition time (TR=3 ms) and post-processed with high-pass and low-pass filters for retrospective cardiac and respiratory gating. The self-gating signal was used for a reconstruction of high-resolution Cine frames of the aortic motion. To assess the local PWV the volume flow Q and the cross-sectional area A of the aorta were determined. The results were compared with the values measured with a triggered Cartesian and an undersampled triggered radial PC-Cine sequence. Results In all examined animals a self-gating signal could be extracted and used for retrospective breath-gating and PC-Cine reconstruction. With the non-triggered measurement PWV values of 2.3±0.2 m/s were determined. These values are in agreement with those measured with the triggered Cartesian (2.4±0.2 m/s) and the triggered radial (2.3±0.2 m/s) measurement. Due to the strong robustness of the radial trajectory against undersampling an acceleration of more than two relative to the prospectively triggered Cartesian sampling could be achieved with the retrospective method. Conclusion With the radial flow-encoding sequence the extraction of a self-gating signal is feasible. The retrospective method enables a robust and fast measurement of the local PWV without the need of additional trigger hardware. KW - pulse-wave velocity KW - mouse KW - self-gating KW - phase-contrast CMR KW - non-triggered KW - retrospective KW - radial KW - aorta Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96602 UR - http://jcmr-online.com/content/15/1/88 ER - TY - JOUR A1 - Munz, Eberhard A1 - Jakob, Peter M. A1 - Borisjuk, Ljudmilla T1 - The potential of nuclear magnetic resonance to track lipids in planta JF - Biochimie N2 - Nuclear Magnetic Resonance (NMR) provides a highly flexible platform for non invasive analysis and imaging biological samples, since the manipulation of nuclear spin allows the tailoring of experiments to maximize the informativeness of the data. MRI is capable of visualizing a holistic picture of the lipid storage in living plant/seed. This review has sought to explain how the technology can be used to acquire functional and physiological data from plant samples, and how to exploit it to characterize lipid deposition in vivo. At the same time, we have referred to the current limitations of NMR technology as applied to plants, and in particular of the difficulty of transferring methodologies optimized for animal/medical subjects to plant ones. A forward look into likely developments in the field is included, anticipating its key future role in the study of living plant. KW - coconut cocos-nucifera KW - H-1-NMR spectroscopy KW - NMR-spectroscopy KW - camelina-sativa KW - high-throughput KW - oil storage KW - seeds KW - accumulation KW - field KW - metabolism KW - NMR KW - Lipid KW - MRI KW - CSI KW - Plants KW - Seeds Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186828 VL - 130 ER - TY - JOUR A1 - Jende, Johann M. E. A1 - Kender, Zoltan A1 - Rother, Christian A1 - Alvarez-Ramos, Lucia A1 - Groener, Jan B. A1 - Pham, Mirko A1 - Morgenstern, Jakob A1 - Oikonomou, Dimitrios A1 - Hahn, Artur A1 - Juerchott, Alexander A1 - Kollmer, Jennifer A1 - Heiland, Sabine A1 - Kopf, Stefan A1 - Nawroth, Peter P. A1 - Bendszus, Martin A1 - Kurz, Felix T. T1 - Diabetic Polyneuropathy Is Associated With Pathomorphological Changes in Human Dorsal Root Ganglia: A Study Using 3T MR Neurography JF - Frontiers in Neuroscience N2 - Diabetic neuropathy (DPN) is one of the most severe and yet most poorly understood complications of diabetes mellitus. In vivo imaging of dorsal root ganglia (DRG), a key structure for the understanding of DPN, has been restricted to animal studies. These have shown a correlation of decreased DRG volume with neuropathic symptom severity. Our objective was to investigate correlations of DRG morphology and signal characteristics at 3 Tesla (3T) magnetic resonance neurography (MRN) with clinical and serological data in diabetic patients with and without DPN. In this cross-sectional study, participants underwent 3T MRN of both L5 DRG using an isotropic 3D T2-weighted, fat-suppressed sequence with subsequent segmentation of DRG volume and analysis of normalized signal properties. Overall, 55 diabetes patients (66 ± 9 years; 32 men; 30 with DPN) took part in this study. DRG volume was smaller in patients with severe DPN when compared to patients with mild or moderate DPN (134.7 ± 21.86 vs 170.1 ± 49.22; p = 0.040). In DPN patients, DRG volume was negatively correlated with the neuropathy disability score (r = −0.43; 95%CI = −0.66 to −0.14; p = 0.02), a measure of neuropathy severity. DRG volume showed negative correlations with triglycerides (r = −0.40; 95%CI = −0.57 to −0.19; p = 0.006), and LDL cholesterol (r = −0.33; 95%CI = −0.51 to −0.11; p = 0.04). There was a strong positive correlation of normalized MR signal intensity (SI) with the neuropathy symptom score in the subgroup of patients with painful DPN (r = 0.80; 95%CI = 0.46 to 0.93; p = 0.005). DRG SI was positively correlated with HbA1c levels (r = 0.30; 95%CI = 0.09 to 0.50; p = 0.03) and the triglyceride/HDL ratio (r = 0.40; 95%CI = 0.19 to 0.57; p = 0.007). In this first in vivo study, we found DRG morphological degeneration and signal increase in correlation with neuropathy severity. This elucidates the potential importance of MR-based DRG assessments in studying structural and functional changes in DPN. KW - diabetic polyneuropathy KW - dorsal root ganglion KW - magnetic resonance neurography KW - neuropathic pain KW - peripheral nervous system Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212459 VL - 14 ER - TY - JOUR A1 - Winter, Patrick M. A1 - Andelovic, Kristina A1 - Kampf, Thomas A1 - Hansmann, Jan A1 - Jakob, Peter Michael A1 - Bauer, Wolfgang Rudolf A1 - Zernecke, Alma A1 - Herold, Volker T1 - Simultaneous measurements of 3D wall shear stress and pulse wave velocity in the murine aortic arch JF - Journal of Cardiovascular Magnetic Resonance N2 - Purpose Wall shear stress (WSS) and pulse wave velocity (PWV) are important parameters to characterize blood flow in the vessel wall. Their quantification with flow-sensitive phase-contrast (PC) cardiovascular magnetic resonance (CMR), however, is time-consuming. Furthermore, the measurement of WSS requires high spatial resolution, whereas high temporal resolution is necessary for PWV measurements. For these reasons, PWV and WSS are challenging to measure in one CMR session, making it difficult to directly compare these parameters. By using a retrospective approach with a flexible reconstruction framework, we here aimed to simultaneously assess both PWV and WSS in the murine aortic arch from the same 4D flow measurement. Methods Flow was measured in the aortic arch of 18-week-old wildtype (n = 5) and ApoE\(^{−/−}\) mice (n = 5) with a self-navigated radial 4D-PC-CMR sequence. Retrospective data analysis was used to reconstruct the same dataset either at low spatial and high temporal resolution (PWV analysis) or high spatial and low temporal resolution (WSS analysis). To assess WSS, the aortic lumen was labeled by semi-automatically segmenting the reconstruction with high spatial resolution. WSS was determined from the spatial velocity gradients at the lumen surface. For calculation of the PWV, segmentation data was interpolated along the temporal dimension. Subsequently, PWV was quantified from the through-plane flow data using the multiple-points transit-time method. Reconstructions with varying frame rates and spatial resolutions were performed to investigate the influence of spatiotemporal resolution on the PWV and WSS quantification. Results 4D flow measurements were conducted in an acquisition time of only 35 min. Increased peak flow and peak WSS values and lower errors in PWV estimation were observed in the reconstructions with high temporal resolution. Aortic PWV was significantly increased in ApoE\(^{−/−}\) mice compared to the control group (1.7 ± 0.2 versus 2.6 ± 0.2 m/s, p < 0.001). Mean WSS magnitude values averaged over the aortic arch were (1.17 ± 0.07) N/m\(^2\) in wildtype mice and (1.27 ± 0.10) N/m\(^2\) in ApoE\(^{−/−}\) mice. Conclusion The post processing algorithm using the flexible reconstruction framework developed in this study permitted quantification of global PWV and 3D-WSS in a single acquisition. The possibility to assess both parameters in only 35 min will markedly improve the analyses and information content of in vivo measurements. KW - 4D flow KW - pulse wave velocity KW - wall shear stress KW - radial KW - self-navigation KW - mouse KW - aortic arch KW - atherosclerosis KW - mice KW - flow KW - plaque KW - CMR KW - quantification KW - microscopy Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259152 VL - 23 IS - 1 ER - TY - JOUR A1 - Kaireit, Till F. A1 - Sorrentino, Sajoscha A. A1 - Renne, Julius A1 - Schoenfeld, Christian A1 - Voskrebenzev, Andreas A1 - Gutberlet, Marcel A1 - Schulz, Angela A1 - Jakob, Peter M. A1 - Hansen, Gesine A1 - Wacker, Frank A1 - Welte, Tobias A1 - Tümmler, Burkhard A1 - Vogel-Claussen, Jens T1 - Functional lung MRI for regional monitoring of patients with cystic fibrosis JF - PLoS ONE N2 - Purpose To test quantitative functional lung MRI techniques in young adults with cystic fibrosis (CF) compared to healthy volunteers and to monitor immediate treatment effects of a single inhalation of hypertonic saline in comparison to clinical routine pulmonary function tests. Materials and methods Sixteen clinically stable CF patients and 12 healthy volunteers prospectively underwent two functional lung MRI scans and pulmonary function tests before and 2h after a single treatment of inhaled hypertonic saline or without any treatment. MRI-derived oxygen enhanced T1 relaxation measurements, fractional ventilation, first-pass perfusion parameters and a morpho-functional CF-MRI score were acquired. Results Compared to healthy controls functional lung MRI detected and quantified significantly increased ventilation heterogeneity in CF patients. Regional functional lung MRI measures of ventilation and perfusion as well as the CF-MRI score and pulmonary function tests could not detect a significant treatment effect two hours after a single treatment with hypertonic saline in young adults with CF (p>0.05). Conclusion This study shows the feasibility of functional lung MRI as a non-invasive, radiation-free tool for monitoring patients with CF. KW - Physics KW - Magnetic resonance imaging KW - Functional magnetic resonance imaging KW - Cystic fibrosis KW - Oxygen KW - Pulmonary imaging KW - Hypertonic KW - Pulmonary function KW - Quantum chronodynamics Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172457 VL - 12 IS - 12 ER - TY - JOUR A1 - Straßer, Marion A1 - Schrauth, Joachim H. X. A1 - Dembski, Sofia A1 - Haddad, Daniel A1 - Ahrens, Bernd A1 - Schweizer, Stefan A1 - Christ, Bastian A1 - Cubukova, Alevtina A1 - Metzger, Marco A1 - Walles, Heike A1 - Jakob, Peter M. A1 - Sextl, Gerhard T1 - Calcium fluoride based multifunctional nanoparticles for multimodal imaging JF - Beilstein Journal of Nanotechnology N2 - New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{−1}\)·s\(^{−1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{−1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging. KW - calcium fluoride nanoparticles KW - magnetic resonance imaging (MRI) KW - multifunctional nanoparticles KW - multimodal imaging KW - photoluminescence Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170657 VL - 8 ER - TY - JOUR A1 - Yilmaz, Ali A1 - Rösch, Sabine A1 - Klingel, Karin A1 - Kandolf, Reinhard A1 - Helluy, Xavier A1 - Hiller, Karl-Heinz A1 - Jakob, Peter M A1 - Sechtem, Udo T1 - Molecular magnetic resonance imaging (MRI) of inflamed myocardium using ferucarbotran in patients with acute myocardial infarction JF - Journal of Cardiovascular Magnetic Resonance N2 - Introduction: Superparamagnetic iron oxide nanoparticle (SPIO)-based molecular imaging agents targeting macrophages have been developed and successfully applied in animal models of myocardial infarction. KW - Acute Myocardial Infarction KW - Cardiovascular Magnetic Resonance KW - Iron Oxide Nanoparticle KW - Superparamagnetic Iron Oxide KW - Infarct Zone Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140991 VL - 13 IS - Suppl. 1 ER -