Jüri Vedru

Associate Professor of Medical Physics, Ph.D.

Institute of Experimental Physics and Technology

University of Tartu

Tähe 4-233

51010 Tartu

Estonia

http://www.physic.ut.ee/~vedru

phones: +372-7-375530, +372-7-422512, +372-7-380292

fax: +372-7-375858

vedru@ut.ee

UNIVERSITY OF TARTU (UTar)

History

Separate chair or institute of physiology exists in the University of Tartu (UTar) since 1860. The research in physiology of circulation and respiration was especially intensified in 1920-30ies when well known Swiss physiologist Prof. Alfred Fleisch was leading the Institute. This in­flu­ence still remains its positive impact. Now also the Institute of Experimental Physics and Techology, University of Tartu, belongs to the centres of scientific research on medical physics and physiological measurement in Estonia. Among numerous fields of re­search of the institute, there are medical physics and biomedical engineering, methods of physiological measurement. Modelling of physiological objects and systems has been pursued also.

Nowadays' Research

1) The Research Group of Medical Physics and Biomedical Engineering at the Institute of Experimental Physics and Technology, has concentrated its efforts to the electric impedance methods for cardiac output measurement. By 1995 the group has recognised limited clinical capabilities of the conventional electric impedance methods for cardiac output mea­su­rement and turned to Foucault cardiography (FCG) - the use of high-frequency Foucault (eddy) currents for tracking the mechanical activity of the heart. Now the main research topic of the group is FCG.

The leader of this research is Jüri Vedru, Ph.D., Associate Professor of Medical Physics at the Institute of Experimental Physics and Technology, UTar. Presently the rest of the team consists of doctoral and master students of the medical physics and biomedical engineering branch of the speciality Applied Physics of UTar. The group works in contact with doctors of the Medical Faculty, UTar, and Tartu University Clinics. We have also close contacts with computer science researchers of the Institute of Technology, UTar.

The research has the further objective to develop an automatic clinical method for the monitoring of the biomechanical functions and parameters of the human heart (firstly, of the cardiac output but also of the functional state parameters of myocardium, e.g. contractility, compliance and viscosity).

The following hypotheses are expected to form the basis to accomplish the objective:

1)      Foucault cardiogram is determined by a volume integral over space around the inductor, which depends on the time-variable conductivity distribution in the thorax. This is the reason of the link between the cardio-synchronous component of FCG and the motion and the blood content variation of the heart.

2)      We believe that the FCG method can supply us with the information necessary to track the atleast the relative variations of the stroke volume and the biomechanical properties of myocardium.

3)      Recording of FCG by several inductors that should be fixed relative each other and suitably positioned – the multiple-inductor FCG – will supply us with a complex of signals that would enable to track the motion of the heart with discrimination between its different components (contractile, breathing-originated and inertial).

For the investigations of the Foucault cardiography (FCG), minimally necessary equipment for the signal recording has been developed and the primary properties of the FCG signal have been investigated. To investigate the method by simulation, a model of heart shape and position dynamics during the heart contraction-dilatation cycle has been developed. For necessary calculations of the eddy current fields in human thorax (as a volume conductor with complex shape and conductivity distribution) finite difference method has been used.

The recent results of studies on this method can be found, e.g. in [Trolla J., Vedru J. On the Safety of Foucault Cardiography. - Proc. XI Int. Conf. Electrical Bio-impedance, Oslo, June 17-21, 2001. - Oslo, 2001. - Pp. 649-652.]

2) Another direction of research on medical physics in the institute is myometry. This is the method for the measurement of the biomechanical properties of the tissue of skeletal muscles. The leader of this research is Arved Vain, Dr. Habil. Biol., Senior Researcher at the Institute of Experimental Physics and Technology, UTar.

For diagnostic purposes at several pathologies and functional diagnostics, it is necessary to compare the states of muscular tissue before and after physiotherapic procedures, massage etc. The principal difference of myometry from traditional practice to measure the skeletal muscle tone via palpation, stretching the muscle or estimating its stiffness, lies in simultaneous measurment of two biomechanical characteristics of the muscle - its elasticity and stiffness. The method can be considered non-invasive and the measurement procedure repeatable.

The device, developed by the researchers especially for those purposes - myometer - has no analogies in the World. Still it enables computerised measurement of the myometric parameters by a skilled operator. The further objective of the research is to create a method and device for the monitoring of time trends of the tone of skeletal muscles.

The recent results of experimental studies on this method can be found, e.g. in [Korhonen R., Vain A., Vanninen E., Viir R., Jurvelin J.S. (1999) Interrelationships of the Interstitial Pressure, Electrical and Mechanical Characteristics of the Skeletal Muscle. Medical & Biological Engineering & Computing Vol.37, supplement 1, 200-201.]

Possible contribution to JPA-s by UTar: 

Cardiovascular (hemodynamical) and biomechanical (myometry) measurements and signal processing

All the tasks of the Integrating activities are essentially important also for us.

However, our skills are best for the following specific tasks:

T1: Sensors: miniaturized, implantable and wireless sensors

Here we have skills on

1) FCG sensors (Foucault or magnetic induction cardiography) for tracking the mechanical activity of the heart.

2) Myometry sensor for measurement of biomechanical properties of the skeletal muscles.

T4: Signal processing, classification, recognition and evaluation

Here we have skills on

1) FCG signal processing.

2) Myometry signal processing and evaluation of the properties of skeletal muscles.

LIST OF RESEARCHERS AND DOCTORAL STUDENTS

Total number of persons: 10 (= 2F+8M)

1. Jüri Vedru, PhD, Assoc. Prof. M

Presently: Assoc. Professor of Medical Physics - UTar, Inst. of Experimental Physics and Technology; Member of the Estonian Society of Biomedical Engineering and Medical Physics, thee International Society for Bioelectromagnetism, Nordic Electrical Bioimpedance Club.

Born: Dec. 24, 1948.

Education: 1972 - UTar, theoretical physics, cum laude

1988 - Ph.D, UTar: "Mathematical Model of Cardiovascular System for Simulation Tasks on the Human Circulation".

Career:

1972-1981 Tartu State University, Junior and later Senior Researcher at Dept. of Sports Medicine;

1982-1984 Post-graduate Student at the Bakulev Institute of Cardiovascular Surgery, Academy of Medical Sci. of the USSR, Moscow;

1985-1992 at Inst. of General and Molecular Pathology (IGMP) of the University of Tartu (UTar): Engineer > Researcher

1992-1997 half-time Sen. Researcher at IGMP & half-time Assoc. Prof. at Inst. for Teaching Physics, UTar;

1997-2002 half-time Sen. Researcher Inst. of Physiology, & half-time Assoc. Prof. Inst. of Materials Science, UTar;

2002 - Assoc. Prof. Inst. of Experimental Physics and Technology, UTar

Current research program: Foucault Cardiography; computer simulation of circulatory system.

2. Arved Vain, Dr. Habil. Biol..M

Presently: Half-time Senior Researcher - UTar, Institute of Experimental Physics and Technology; Member of the Board of the Estonian Olympic Academy, Editor in Chief of Acta Academiae Olympiquae Estoniae.

Member of the Estonian Physiological Society and the International Biomechanical Society.

Born: Oct. 29, 1936

Education: 1961 Tallinn Polytechnical Institute, mechanical engineer.

1970 - PhD, UTar, "On the dynamics of movements in unsupported state” .

1993 - Dr. Habil. Biol., Latvian Institute of Orthopedics and Traumatology in Riga, “The phenomenon of mechanical stress transmission in skeletal muscles”

Career:

1964 working at the University of Tartu,

1970 - 1983 Senior Researcher and Lecturer, UTar, Dept. of Sports Physiology;

1983 - 1989 Associate Professor, Head of Dept. of Gymnastics and Biomechanics, UTar;

1989 - Senior Researcher, UTar, Inst. of Experimental Physics and Technology.

Current research program: Biomechanics of skeletal muscles, Functional Diagnostics and Monitoring of skeletal muscles..

3. Jüri Samarütel PhD, Assoc. Prof. M

Presently: Assoc. Professor - UTar, Clinic of Anaesthesiology and Intensive Care; Chairman of the Board of the Estonian Society of Anesthesiologists; Councillor on Anesthesiology at the Social Ministry.

Born: Apr. 17, 1938

Education: 1962 - UTar, Medical Faculty

1974 - Ph.D, UTar

Career:

1962-1965 – Tartu Republican Clinical Hospital, anestesiologist;

1965-1968 and

1971-1975 – the same hospital, Head of the Ward of Anesthesiology.

1968-1977 - UTar, Assistant Professor,

1977 – still - UTar, Associate Professor.

Current research program: Anesthesiology, Patient Monitoring.

4. Anatoli Landyr PhD, Assoc. Prof. M

Presently: Assoc. Professor - UTar, Clinic of Sports Medicine and Rehabilitation; Member of the Estonian Society of Sports Physicians,

Estonian Federation of Sports Medicine, Estonian Society of Cardiologists, European Society of Cardiologists and secretary of the Baltic Association of Sports Medicine.

Born: July 4, 1946

Education: 1970 - UTar, Medical Faculty

1981 - PhD, UTar, "Automatic quantitative evaluation of athlete’s heart contractility”

Career:

1970-1971 – Tartu Centre of Sports Medicine, internature physician

1971-1977 – Tartu Centre of Sports Medicine, sports physician

1977-1981 – UTar, Department of Sports Medicine, researcher

1981-1984 – UTar, Department of Sports Medicine, Assistant Professor

1984 - still – UTar, Clinic of Sports Medicine, Associate Professor

Current research program: Sports Medicine, especially Functional Diagnostics.

5. Helena Gapeyeva PhD, Researcher, F

Presently: : Researcher – UTar, Institute of Exercise Biology and Physiotherapy, International Society of Physical Medicine and Rehabilitation,

International Association of Physical Education and Sport for Girls and Women, Estonian Association of Physician in Rehabilitation,

Estonian Federation of Sports Medicine, Estonian Society of Physician in Physiotherapy

Born: September 18, 1958

Education: 1982 - UTar, Medical Faculty, cum laude

1993, 1998 - UTar, Medical Faculty, Physician in Rehabilitation of II and I Category

2002 – PhD, UTar (Knee extensor muscle function after partial arthroscopic meniscectomy)

Career:

1982-1983 – UTar, Department of Exercise Physiology, Senior Assistant

1983-1990 – UTar, Department of Gymnastics and Biomechanics, Senior Assistant and Researcher

1990-1998 – UTar, Department of Exercise Physiology, Researcher and Senior Assistant

since 1998 – UTar, Institute of Exercise Biology and Physiotherapy, Senior Assistant

2003 – UTar, Institute of Exercise Biology and Physiotherapy, Researcher (Kinesiology)

Current research program:

Knee extensor muscle function, contractile properties of human skeletal muscles, neuromuscular adaptation during power and endurance training, effect of aging on motor functions, exercise therapy, neuromuscular fatigue.

6. Kalle Kepler MSc M

Presently: Director - UTar, Training Centre of Medical Physics and Biomedical Engineering (BMTK); Member of Board of the Estonian Society for Biomedical Engineering and Medical Physics; Member of Institute of Physics (IOP, UK), Estonian Physical Society, Estonian Society for Quality, Estonian Association of Engineers

Born: July 28, 1959

Education: 1982 - UTar, physics (electronics) - cum laude

2001 - MSc, UTar, Applied Physics (medical physics), "Patient dose and Radiation Risk in Paediatric Radiography"

Career:

1984 – 1997 Senior Researcher, UTar, Inst. of Experimental Physics and Technology

1997 – Director of BMTK, lecturer of courses of medical physics

1999 – 2000 with PHARE projects for translation and adaptation of CENELEC medical electrical equipment standards and MEDDEV documents in Estonia

Current research program: Conformity assessment of medical devices, patient dosimetry.

7. Tatjana Kums MSc F

Presently: UTar, Doctoral Student, Institute of Exercise Biology and Physiotherapy

Born: Aug. 23, 1952

Education: 1974 - UTar, teacher of physical training and sports

1997 – UTar - MSc, Faculty of Exercise and Sports Sciences, "Immediate adaptation reactions of the locomotive apparatus of female gymnasts to training loads"

Career:

1975 - 1986 - UTar, Junior Researcher at the Dept. of Sports Physiology.

1986 - 1990 - UTar, Teacher at the Dept. of Physical Training and Sports

1990 - 1998 – UTar, Senior Laboratory Assistant at the Institute of Sports Pedagogy

1998 - 2003 - UTar, Doctoral Student, Institute of Exercise Biology and Physiotherapy

2003 - UTar, Laboratory Assistant, Institute of Exercise Biology and Physiotherapy

Current research program: Resistance of locomotive apparatus to training loads

8. Sergei Malchenko MSc M

Presently: Doctoral Student - UTar, Institute of Experimental Physics and Technology

Born: April 8, 1973

Education: 1997: UTar, B.Sc. , physics

2000: UTar, M.Sc. , applied physics (medical physics and biomedical engineering) "Model of the Shape of the Surface of Pulsing Heart"

Career:

2000 – UTar, Faculty of Physics and Chemistry, Doctoral Student

Current research program: Foucault cardiography

9. Konstantin Skaburskas MSc M

Presently: Doctoral Student - UTar, Institute of Experimental Physics and Technology

Born: Oct. 10, 1972

Education: 1998: UTar, B.Sc. , physics

2000: UTar, M.Sc. , applied physics (medical physics and biomedical engineering) "Solving of the Direct Problem of Foucault Cardiography "

Career:

2000 – UTar, Faculty of Physics and Chemistry, Doctoral Student

Current research program: Foucault cardiography

10. Jaanus Trolla MSc M

Presently: Doctoral Student - UTar, Institute of Experimental Physics and Technology

Born: June 23, 1973

Education: 1996: UTar, B.Sc. , physics

2000: UTar, M.Sc. , applied physics (medical physics and biomedical engineering) "Design and Study of a Foucault Cardiograph "

Career:

2000 – UTar, Faculty of Physics and Chemistry, Doctoral Student

Current research program: Foucault cardiography