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Home arrow Selected Results arrow 2014 arrow Selected Results of Basic Research
Selected Results of Basic Research
  • The investigation of muscle and liver energy metabolism using novel phosphorus MR spectroscopy and imaging localization methods
  • 3D visualization of objects and their internal microstructures in natural sciences using X-ray microtomography
  • Algorithm for estimating parameters of an ellipse based on regression method with a non-linear constraints and its application to determination of the measurement uncertainty of the phase measured by quadrature homodyne interferometer
  • Magnetometric measurement of low concentrations of coated iron oxide nanoparticles
  • Classification of ischemic lesions identification results obtained by inverse solution

Result 1: The investigation of muscle and liver energy metabolism using novel phosphorus MR spectroscopy and imaging localization methods

Projects: VEGA 2/0013/14 a  APVV-0513-10,   (Institute of Measurement Science SAS)
Authors: L. Valkovič,  I. Frollo
The chemical reactions rates of phosphorus energy metabolism in individual muscle groups and in the liver are important markers of pathophysiology of these organs as well as of the whole organism.
New 31P-MRS method for precise localization of dynamic changes of phosphorus metabolites for the measurement of energy metabolism of the liver and muscles (1D-ISIS) was developed.
Proposed method was tested and optimized for measurement of the liver metabolism at rest and muscle metabolism of the patient during dynamic exercise in an ergometer dedicated for plantar flexion exercise. High reproducibility of the results was found on a 7T MR system.
Liver metabolism measurement technique was successfully tested in patients with non-alcoholic fatty liver and steatohepatitis. Developed methods will find their application in the examination of physiological and pathophysiological changes in human metabolism.
Co-operating Institution: Univ.-Prof. Dr. Siegfried Trattnig, MR Center, Highfield MR, Department of Radiology, Medical University of Vienna, Austria.
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Fig. 1. Test of the localization performance of the developed 1D-ISIS sequence. (a) phantom image with depicted localization volume; (b) 31P-MR spectrum measured without localization and (c) using 1D-ISIS localization method.

Publications:

  1. VALKOVIČ, Ladislav - CHMELÍK, M. - JUST KUKUROVÁ, I. - JAKUBOVÁ, M. - KIPFELSBERGER, M.Ch. - KRUMPOLEC, P. - TUŠEK JELENC, M. - BOGNER, W. - MEYERSPEER, M. - UKROPEC, J. - FROLLO, Ivan - UKROPCOVÁ, B. - TRATTNIG, S. - KRŠŠÁK, M. Depth-resolved surface coil MRS (DRESS)-localized dynamic 31P-MRS of the exercising human gastrocnemius muscle at 7 T. In NMR in Biomedicine, 2014, vol. 27, no. 11, p. 1346-1352. ISSN 0952-3480. (3.559-IF2013)
  2. VALKOVIČ, Ladislav - GAJDOŠÍK, M. - TRAUSSNIGG, S. - WOLF, P. - CHMELÍK, M. - KIENBACHER, Ch. - BOGNER, W. - KREBS, M. - TRAUNER, M. - TRATTNIG, S. - KRŠŠÁK, M. Application of localized 31P MRS saturation transfer at 7 T for measurement of ATP metabolism in the liver: Reproducibility and initial clinical application in patients with non-alcoholic fatty liver disease. In European Radiology, 2014, Vol. 24, no. 7, p. 1602-1609. ISSN 0938-7994. (4.338-IF2013)
  3. VALKOVIČ, Ladislav - BOGNER, W. - GAJDOŠÍK, M. - POVAŽAN, M. -  JUST KUKUROVÁ, I. - KRŠŠÁK, M. - GRUBER, S. - FROLLO, Ivan - TRATTNIG, S. - CHMELÍK, M. One-dimensional image-selected in vivo spectroscopy localized phosphorus saturation transfer at 7T. In Magnetic Resonance in Medicine, 2014, vol. 72, no. 6, p. 1509-1515. ISSN 0740-3194. (3.398-IF2013)
  4. GAJDOŠÍK, M. - CHMELÍK, M. - JUST KUKUROVÁ, I. - BOGNER, W. - VALKOVIČ, Ladislav - TRATTNIG, S. - KRŠŠÁK, M. Vivo relaxation behavior of liver compounds at 7 Tesla, measured by single-voxel proton in MR spectroscopy. In Journal of Magnetic Resonance Imaging, 2014, vol. 40, no. 6, p. 1365-1374. ISSN 1053-1807. (2.788-IF2013)
  5. HOCK, A. - VALKOVIČ, Ladislav - GEIER, A. - KUNTZEN, T. - BOESIGER, P. -  HENNING, A. Navigator based respiratory gating during acquisition and preparation phases for proton liver spectroscopy at 3 T. In NMR in Biomedicine, 2014, vol. 27, no. 3, p. 348-355. ISSN 0952-3480. (3.559-IF2013)
  6. JUST KUKUROVÁ, I. - VALKOVIČ, Ladislav - BOGNER, W. - GAJDOŠÍK, M. - KRŠŠÁK, M. - GRUBER, S. - TRATTNIG, S. - CHMELÍK, M. Two-dimensional spectroscopic imaging with combined free induction decay and long-TE acquisition (FID echo spectroscopic imaging, FIDESI) for the detection of intramyocellular lipids in calf muscle at 7 T. In NMR In Biomedicine, 2014, Vol. 27, p. 980-987. ISSN 0952-3480. (3.559-IF2013) 

Result 2: 3D visualization of objects and their internal microstructures in natural sciences using X-ray microtomography

Projects: VEGA   (Institute of Measurement Science SAS)
Author: M. Hain
There were designed and applied optimized micro-tomographic methods of three-dimensional visualization of objects and their internal microstructures of selected objects and materials. Under the proposal of new methodologies the conditions of microtomographic measurements were optimized for specific objects, e.g. selection of optimized accelerator voltage, current, time of signal accumulation on the detector, the number of repetitions, relaxation time, material of target and the number of X-ray projections. In the field of processing and visualization of results of microtomographic measurement the new methodologies were developed for 3D visualization of microstructures with the application of methods for data filtering, rendering and image segmentation.The results were applied together with Doc. RNDr. Jozef Klembara, DrSc. from the Faculty of Natural Sciences at the comparative anatomical study of the genus anguinae, with Ing. Pavol Kováč, DrSc. from the IEE SAS at the microtomographic analysis of longitudinal inhomogeneity of MgB2 superconductors and Dr. Ďurmeková and Dr. Růžička of the Faculty of Natural Sciences at the microtomographic analysis of rocks and minerals.
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Fig. 1. Microtomographic visualization of the lower jaw and dental bone of six representatives of the genus anguinae (after digital processing and image segmentation, voxel resolution of 10 microns).

 Publications:

 

  1. KLEMBARA, J. - HAIN, M. - DOBIASOVA, K. Comparative anatomy of the lower jaw and dentition of Pseudopus apodus and the interrelationships of species of subfamily Anguinae (Anguimorpha, Anguidae). In The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology, 2014, vol. 297, no. 3, p. 516-544.
  2. HUŠEK, I. - KOVÁČ, P. - ROSOVÁ, A. - MELIŠEK, T. - PACHLA, W. - HAIN, M. Advanced MgB2 wire made by internal magnesium diffusion process. In Journal of Alloys and Compounds, 2014, vol. 588, p. 366-369.
  3. DURMEKOVÁ, T. - RUŽIČKA, P. - HAIN, M. - ČAPLOVIČOVÁ, M. Changes in marble quality after sodium sulphate crystallization and long-lasting freeze-thaw testing. In Engineering Geology for Society and Territory - Volume 5 : Urban Geology, Sustainable Planning and Landscape Exploitation. Springer, 2015. ISBN 978-3-319-09047-4, p. 237-241.

Result 3: Algorithm for estimating parameters of an ellipse based on regression method with a non-linear constraints and its application to determination of the measurement uncertainty of the phase measured by quadrature homodyne interferometer

Projects: APVV-0096-10, VEGA 1/0038/12, VEGA 1/0043/13 (Institute of Measurement Science SAS)
Author: V. Witkovský
Optical interferometers are significantly used in dimensional metrology and its applications. Among them, an important part is based on the quadrature homodyne interferometers, which allows to perform very precise measurements (with sub-nanometer precission). The interferometers generate two interference sinusoidal signals, which are ideally shifted 90°, and allows very sensitive detection of directional movement (shift) by using the corresponding phase change. In real applications, the measured signals shows many deviations from the ideal condition (e.g. offset the zero level signal, unequal amplitude of the signals, the phase shift from the ideal value of 90°). Such signals can be simultaneously modeled by using the parameters of the ellipse, to be determined (estimated) from the measured data which are subject to further biases and measurement errors. For demodulation and back-compensation of those signals is typically used the so-called Haydeman correction. Although this method is often used, the proper determination of uncertainty of the measurement results based on the quadrature homodyne interferometer measurements with application of such a correction is still problematic. Collaboration of the researchers from the Institute of Measurement Science of SAS, Mathematical Institute od SAS and the PTB in Braunschweig (Physikalisch-Technische Bundesanstalt, Germany) have lead to the orginal proposal of methods and algorithms for parameter estimation of the ellipse based on minimizing the geometric distance, which lead to the locally best linear unbiased estimates (BLUEs) of the parameters. The proposed method allows simultaneously to estimate the related statistical uncertainties, including the uncertainties of the estimated phases and/or displacements, respectively.

Partners: Prof. RNDr. G. Wimmer, DrSc. (Mathematical Institute SAS), Dr. R. Koening (Physikalisch-Technische Bundesanstalt, Braunschweig, Germany)

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Obr. 1. Schematic illustration of the principle and of a typical measured signals by using the quadrature homodyne interferometer (BS = Beam Splitter, PBS = Polarizing Beam Splitter). The new method allows to determine the expanded measurement uncertainty of the measured phase and/or the estimated length offsets (displacements).

Publications:

 

  1. KÖNING, R. - WIMMER, G. - WITKOVSKÝ, V.: Ellipse fitting by nonlinear constraints to demodulate quadrature homodyne interferometer signals and to determine the statistical uncertainty of the interferometric phase. Measurement Science and Technology 25 (Number 11, November 2014 ), 2014, 115001 (11pp), doi:10.1088/0957-0233/25/11/115001. (CC publikácia)
  2. KÖNING, R. - WIMMER, G. - WITKOVSKÝ, V.: EllipseFit4HC: A Matlab algorithm for demodulation and uncertainty evaluation of the quadrature interferometer signals. In: F. Pavese, A. Chunovkina, editors, Advanced Mathematical and Computational Tools in Metrology and Testing X.St. Petersburg, Russia, September 9-12, 2014, World Scientific Publ. Co., Singapore. 2014, Submitted.
  3. KÖNING, R. - WITKOVSKÝ, V. - WIMMER, G.: The statistical uncertainty of the Heydemann Correction. A practical limit of optical quadrature homodyne interferometry. In: Macroscale 2014, Dimensional and related measurements at the macroscopic scale. Federal Office for Metrology and Surveying, Vienna, Austria, October 28-30, 2014.
  4. KÖNING, R. - WIMMER, G. - WITKOVSKÝ, V.: The statistical uncertainty of the Heydemann Correction - A practical limit of optical quadrature homodyne interferometry. Measurement Science and Technology, 2014, Submitted.

Result 4: Magnetometrické merania nízkych koncentrácií obalovaných nanočastíc oxidov železa

Projects: VEGA 2/0152/13 a VEGA 2/0143/13 (Institute of Measurement Science SAS)
Authors: M. Škrátek, I. Šimáček, A. Dvurečenskij, M. Majerová, J. Maňka, Cigáň
Obalované magnetické nanočastice sú perspektívnymi nosičmi liečiv pri cielenej terapii. Pri tejto aplikácii je dôležité poznať rozloženie (koncentráciu) nanočastíc v jednotlivých orgánoch, resp. častiach tela. Naša štúdia bola zameraná na vyšetrovanie rôznych parametrov ovplyvňujúcich minimálnu detegovateľnú úroveň pri magnetometrických meraniach nízkych koncentrácií nanočastíc v suspenzných modelových vzorkách pomocou špeciálne upraveného vlastného SQUID gradiometrického systému a SQUID systému MPMS XL 7 AC od firmy Quantum Design. Vyšetrovaný a analyzovaný bol vplyv média, veľkosti vzorky a jej polohy voči snímaču. Závery štúdie poskytujú cenné informácie pre problematiku merania koncentrácie nanočastíc v orgánoch malých laboratórnych zvierat.

Publication:

 

  1. ŠKRÁTEK, Martin - ŠIMÁČEK, Ivan - DVUREČENSKIJ, Andrej - MAJEROVÁ, Melinda - MAŇKA, Ján. Magnetometric measurements of low concentration of coated Fe3O4 nanoparticles. In Acta Physica Polonica A, 2014, vol. 126, no. 1, p. 396-397. ISSN 0587-4246. (0.604-IF2013)

 

Result 5: Classification of ischemic lesions identification results obtained by inverse solution

 

Projects: VEGA No. 2/0131/13, APVV No. APVV-0513-10
Authors: J. Švehlíková, M. Teplan, M. Tyšler
The method for localization of two lesions with changed repolarization by inverse solution to two dipoles assumes that the equivalent electrical generator of each lesion is one dipole. For simulated pairs of lesions the correct localization was obtained in 81-86% of cases depending on the simulated noise in input difference integral maps (SNR 20, 30, 40 dB) and the localization error of the correctly localized lesions was 1.1±0.7 cm. To use the method, it is necessary to distinguish the pairs of lesions from other cases (single or more lesions). To solve this problem 23 characteristics/features of the solutions were specified as classification input to identify the cases with two lesions. The quadratic discriminant analysis with cross-validation was used for the classification. Using the selective forward greedy algorithm 4 features were specified that lead to sensitivity and specificity of the decision about the presence more than 90% for all simulated levels of noise in input data.

 

Publications:

 

  1. ŠVEHLÍKOVÁ, Jana - TEPLAN, Michal - TYSLER, Milan.: Identification of two lesions with local repolarization changes using two dipoles in the Inverse solution. In: Measurement 2013: 9th International Conference on Measurement. Eds. J. Maňka, M.Tyšler, V. Witkovský, I. Frollo. Bratislava: Institute of Measurement Science, SAS, 2013, p. 93-96. ISBN 978-80-969-672-5-4.
  2. SVEHLIKOVA, Jana. - TEPLAN, Michal. - TYSLER, Milan.: Classification of inverse solutions to two dipoles. Computing in Cardiology 2013; vol. 40, p.1127-1130, ISSN 2325-8861.
  3. SVEHLIKOVA Jana - TEPLAN Michal - TYSLER Milan: Identification of two lesions with local repolarization changes using two dipoles in inverse solution. Simulation study. Computers in Biology and Medicine, 2015, vol. 57, p. 96-102. (1.240 - IF2014). (2015 - Current Contents). ISSN 0010-4825.
 
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