• Measurement of muscle metabolism using phosphorus spectroscopy on ultra-high fields
• Advanced quantitative imaging of the degeneration of meniscus, Achilles tendon and cartilage under loading using MRI
  
• Noninvasive localization of ectopic activity in the heart
  
• Cooperation in the development of electronic modules designed for computer control of cycle of magnetic field in Nuclotron accelerator in Dubna
  

Result 1: Measurement of muscle metabolism using phosphorus spectroscopy on ultra-high fields

Projects: Projekt VEGA 2/0090/11 a  ŠPVV no. 2003SP200280203

Authors: L. Valkovič, P. Szomolányi, V. Juráš, I. Frollo

A new non-invasive method was developed and tested in muscle tissue for the measurement of creatine-kinase reaction rate based on phosphorus magnetization transfer. The feasibility of this type of experiment was tested at 7T MRI, with the conclusion that it can be performed 2.7 to 3.4 times faster compared to the same protocol at 3T. Further research was dedicated to measure muscle metabolism at rest and during physical exercise. Our findings show that magnetization transfer can be used as an alternative method for oxidative metabolism evaluation in stroke and uncooperative patients.

In addition, a new two-dimensional MR method based on spectroscopic imaging of chemical shift was developed and tested in vivo. Using newly developed pulses for excitation, a reduction of chemical shift artifacts in MR data can be achieved in range of 1.5-7.7 times. This reduction was experimentally tested in phantoms and this newly developed method was shown feasible for measurements of liver (volunteers) in clinically acceptable measurement time. The reproducibility of the results was tested on ultra-high field MR system of 7T.

Co-operating institution: Univ.-Prof. Dr. Siegfried Trattnig, MR Center, Highfield MR, Department of Radiology, Medical University of Vienna, Austria.

Fig 1 a: sample In-vivo measurement of the human calf muscle on 7T MR system. The grid represents the volumes, in which the MR spectroscopic evaluation was performed. The total measurement time was 6 minutes and 58 seconds. b: Time evolution of the 31P spectrum at rest, during exercise and consecutive recovery.

Publications:

1.   VALKOVIČ, Ladislav - CHMELÍK, M. - KUKUROVÁ, I.J. - KRŠŠÁK, M. -  GRUBER, S. - FROLLO, Ivan - TRATTNIG, S. - BOGNER, W. Time-resolved phosphorous magnetization transfer of the human calf muscle at 3 T and 7 T: A feasibility study. In European Journal of Radiology, 2013, vol. 82, no. 5, p. 745-751. ISSN 0720-048X. (2.512-IF2012).

2.   VALKOVIČ, Ladislav - UKROPCOVÁ, B. - CHMELÍK, M. - BALÁŽ, M. - BOGNER, W. - SCHMID, A.I. - FROLLO, Ivan - ZEMKOVÁ, E. - KLIMEŠ, I. - UKROPEC, J. - TRATTNIG, S. - KRŠŠÁK, M. Interrelation of 31P-MRS metabolism measurements in resting and exercised quadriceps muscle of overweight-to-obese sedentary individuals. In NMR in Biomedicine, 2013, vol. 26, no. 12, p. 1714-1722. ISSN 0952-3480. (3.446-IF2012).

3.   CHMELÍK, M. - KUKUROVÁ, I.J. - GRUBER, S. - KRŠŠÁK, M. - VALKOVIČ, Ladislav - TRATTNIG, S. - BOGNER, W. Fully adiabatic 31P 2D-CSI with reduced chemical shift displacement error at 7 T - GOIA-1D-ISIS/2D-CSI. In Magnetic Resonance in Medicine, 2013,  vol. 69, no. 5, p. 1233-1244. ISSN 0740-3194. (3.267-IF2012)

4.   FRUEHWALD-PALLAMAR, J. - SZOMOLÁNYI, Pavol - FAKHRAI, N. - LUNZER, A. - WEBER, M. - THURNHER, M.M. - PALLAMAR, M. - TRATTNIG, S. - PRAYER, D. - NOEBAUER-HUHMANN, I.M. Parallel imaging of the cervical spine at 3T: Optimized trade-off between speed and image quality. In American Journal of Neuroradiology, 2012, vol. 33, no. 10, p. 1867-1874. ISSN 0195-6108. (3.167-IF2012).

Result 2: Noninvasive localization of ectopic activity in the heart

Projects: VEGA 2/0131/13, APVV-0513-10

Authors: M. Tyšler, J. Švehlíková, O. Punschykova, J. Lenková

A method for localization of the focus of ectopic heart activity using multichannel ECG measurement and whole-torso CT imaging was proposed. It is supposed that the searched local pathology can be represented by a dipole. In a simulation study the influence of torso approximation accuracy on the result of the localization was observed. It was found that the use of a common torso model modified only according to patient anthropometric parameters causes a mean localization error of 3.4 ± 1.1 cm. If also information on the heart shape was available the error decreased to 1.00 ± 0.7 cm. With a realistic torso model obtained from CT the mean localization error was 0.7 ± 0.7 cm. The method was used in an experimental study on a patient with ectopic ventricular activity. His torso models were based on anthropometric measurements and a CT scan. The noninvasively obtained position of the ectopic focus was in agreement with the result of the invasive intracardial mapping. Both studies confirmed that the use of a torso model with dimensions adapted to a specific patient and with realistic heart model enables to localize the pathological ectopic activity with acceptable accuracy.

Foreign partner: Faculty of biomedical engineering CUT in Prague, Kladno

Fig. 1. Left: CT scan of a patient torso and the initial ectopic activity near the left ventricular base identified by intracardial mapping.
Right: noninvasively estimated position of the initial ectopic activity using a torso model with approximated shape and realistic heart model obtained from CT (b) and torso and heart model obtained from CT (c) (base to apex view).

Publications:

1.   TYŠLER, Milan - ŠVEHLÍKOVÁ, Jana - PUNSCHYKOVA, O. -  LENKOVÁ, Jana. Influence of Torso Model Accuracy on the Noninvasive Localization of Heart Pathologies. Acta Mechanica Slovaca, 2013, vol. 17, no. 3, p. 18-25. ISSN 1335-2393.

2.   LENKOVA, Jana - SVEHLIKOVA, Jana - TYSLER, Milan. Individualized model of torso surface for the inverse problem of electrocardiology. J. of Electrocardiology, 2012, vol. 45, p. 231-236, ISSN (printed): 0022-0736. ISSN (electronic): 1532-8430. (1.109 IF2010).

3.   TYŠLER, Milan - LENKOVÁ, Jana - ŠVEHLÍKOVÁ, Jana. Impact of the Patient Torso Model on the Solution of the Inverse Problem of Electrocardiography. Advances in Electrical and Electronic Engineering, 2013. Prijaté do tlače.

4.   TYŠLER, Milan - LENKOVÁ, Jana - ŠVEHLÍKOVÁ, Jana. Vplyv modelu torza na inverznú lokalizáciu ischémie. In: Trendy v biomedicínskom inžinierstve. Zborník konferencie. Technická univerzita v Košiciach, 2013, 53-56. ISBN 978-80-8086-208-4, EAN 9788080862084.

5.   LENKOVA, Jana - SVEHLIKOVA, Jana - TYSLER, Milan. Impact of Torso Model Fidelity on the Inverse Localization of Ischemia. In: Proceedings of the 40th International Congress on Electrocardiology, 2013, VEDA, 2013, v tlači.

Result 3: Advanced quantitative imaging of the degeneration of meniscus, Achilles tendon and cartilage under loading using MRI

Projects: VEGA 2/0090/11 a  ŠPVV no. 2003SP200280203

Authors: V. Juráš, L. Valkovič, P. Szomolányi, I. Frollo

Within the scope of our project we developed and validated a new method for investigation of menisci and tendons with the novel variable echo time MRI sequence. Unlike conventional methods, this method allows for detecting the signal from menisci and tendons with high resolution. Moreover, with this method it is possible to quantitatively map the transversal relaxation constant T2* which corresponds to the degeneration status of meniscus and tendon. Besides the high resolution, artifact-free images are also a great advantage. Our experiments showed we are able to detect the collagen fiber disruption in connective tissues at early stages. The response of the cartilage to the loading was investigated by T2 constant, whilst the compression was realized directly in the MR scanner using a MR compatible dedicated device. We are able to follow-up the cartilage transplant in time resulting in getting the complex information about the repair site maturation.

 Co-operating institution: Univ.-Prof. Dr. Siegfried Trattnig, MR Center, Highfield MR, Department of Radiology, Medical University of Vienna, Austria.

Publications:

1.   JURÁŠ, Vladimír - APPRICH, S. - SZOMOLÁNYI, Pavol - BIERI, O. - DELIGIANNI, X. - TRATTNIG, S. Bi-exponential T2* analysis of healthy and diseased Achilles tendons: An in vivo preliminary magnetic resonance study and correlation with clinical score. In European Radiology, 2013, vol. 23, no. 10, p. 2814-2822. ISSN 0938-7994. (3.548-IF2012).

2.   JURÁŠ, Vladimír - APPRICH, S. - SZOMOLÁNYI, Pavol - DOMAYER, S. - FROLLO, Ivan - TRATTNIG, S. Bi-exponential T2* analysis of meniscus. In MEASUREMENT 2013 : 9th International Conference on Measurement. Editors J. Maňka, M. Tyšler, V. Witkovský, I. Frollo. - Bratislava : Institute of Measurement Science, SAS, 2013, p. 129-132. ISBN 978-80-969-672-5-4.

3.   SZOMOLÁNYI, Pavol - SCHÖNBAUER, E. - JURÁŠ, Vladimír - ZBÝŇ, Š. - FROLLO, Ivan - TRATTNIG, S. MR T2 study of human knee cartilage using in-vivo compression device. In MEASUREMENT 2013 : 9th International Conference on Measurement. Editors J. Maňka, M. Tyšler, V. Witkovský, I. Frollo. - Bratislava : Institute of Measurement Science, SAS, 2013, p. 133-136. ISBN 978-80-969-672-5-4.

Result 4: Cooperation in the development of electronic modules designed for computer control of cycle of magnetic field in Nuclotron accelerator in Dubna

Projects: -

Authors: Ľ. Ondriš, D. Krušinský

Based on the contract N 08626319 between the Joint Institute for Nuclear Research Dubna, Russian Federation and the Institute of Measurement Science SAS, the electronic modules designed for computer control of cycle of magnetic field in Nuclotron accelerator in the Laboratory of High Energy Veksler and Baldin were developed.

All developed electronic modules are controlled from computer through USB 2.0.

Foreign partner: Joint Institute for Nuclear Research Dubna, Russian Federation.