Title of Invention	ERGOMETER SUITABLE FOR USE IN A MAGNETIC RESONANCE APPARATUS
Abstract	The present invention relates to an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. It comprises at least one drive means which is provided essentially movably and at least one pneumatic piston/cylinder array (7) . The drive means is provided at the piston (20) or the cylinder (21) and pneumatically applied pressure between the piston (20) and the cylinder (21) constitutes a resistance or force to be overcome by the test person or patient by operating the drive means. The resistance or the force necessary to set the drive means in motion, particularly during operation, can be controlled and/or regulated and the piston (20) and the cylinder (21) are sized such that an air cus...

Title of Invention

ERGOMETER SUITABLE FOR USE IN A MAGNETIC RESONANCE APPARATUS

Abstract

The present invention relates to an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. It comprises at least one drive means which is provided essentially movably and at least one pneumatic piston/cylinder array (7) . The drive means is provided at the piston (20) or the cylinder (21) and pneumatically applied pressure between the piston (20) and the cylinder (21) constitutes a resistance or force to be overcome by the test person or patient by operating the drive means. The resistance or the force necessary to set the drive means in motion, particularly during operation, can be controlled and/or regulated and the piston (20) and the cylinder (21) are sized such that an air cus...

Full Text	Our Ref.: L 1520 PCT Ergometer suitable for use in a magnetic resonance apparatus The present invention relates to an ergometer and a process for operating an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance (MR) apparatus. Such examinations are carried out, inter alia, in the fields of medical diagnostics and sports science. Exercising different muscle groups is a frequently used method to examine muscle function in the fields of sports medicine and cardiovascular medicine. What is referred to as the 31P- MRS process (Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy) is a suitable examination process wherein the blood flow in a stimulated muscle is measured locally in a magnetic resonance apparatus. This way, energy metabolites in the muscle, such as for example phosphocreatine, inorganic phosphate or adenosine triphosphate, can be measured quantitatively. By means of the 31P-MRS process it is also possible to record the energy metabolites when exercising the muscles of the calf. Initially, there is a decrease in phosphocreatine when the muscle is exercised to a certain degree until the oxygen supply in the muscle is raised to such an extent that the increased energy requirements can be met by the oxidative metabolism alone. In that case, the phosphocreatine breakdown reaches an equilibrium state. If due to a stenosis in a supplying blood vessel the blood flow and thus the oxygen supply cannot be increased to meet the demand, the phosphocreatine decreases progressively. The use of an ergometer in a strong magnetic field is problematic since many components have to be manufactured from - 1 - non-ferromagnetic metals and/or wood or plastic materials so that the device can be operated in an artefact-free manner and will function correctly, e.g. in a magnetic resonance tomograph. Also, sensors and cables for measuring device parameters such as force and travel have to be provided such that they do not cause measuring artefacts. Furthermore, it has to be possible to set a defined and reproducible force, or resistance, in an ergometer which has to be overcome by a test person or patient to set a drive means, which can e.g. be a pedal, in motion. Furthermore, it is useful if during ergometry the work output can be set, measured, or calculated, and adjusted accordingly while the ergometer is operated. When using an ergometer, the test person or patient presses against a defined resistance at a set frequency, with the deflection angle of the pedal and friction playing an important role as well. The frequency is usually given by a metronome and the force is measured by means of piezo technology. In commercially available ergometers which are operated outside of magnetic fields, the force setting is automatically readjusted via a feedback control system by means of suitable electronic or mechanic devices during the operation if the test person does not maintain the frequency or angle deflection. The use of an ergometer only makes sense if such feedback control systems are in place. The ergometers suitable for use in an MR apparatus which are currently commercially available do not comprise such a feedback control system. Moreover, in the commercially available ergometers the measuring result is falsified in a non-linear manner due to frictional resistance during the motion of the drive means so that a measuring error cannot be calculated reliably. It is therefore the object of the present invention to provide an improved ergometer, and/or an improved ergometer arrangement, which preferably overcomes the disadvantages described above. -2- This object is achieved by the features described in the patent claims. The invention is based on the fundamental idea of providing an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. The test person or patient has to apply a certain force, which can be pre-set, at a drive means in order to set a piston/cylinder array in motion. This essentially causes the piston and the cylinder to move relative to each other. The force necessary to overcome the resistance presented by the piston/cylinder array can be controlled or regulated, in particular during the motion of the drive means. This can be done manually by specialist staff or with the help of appropriate instructions e.g. from an instructing computer program wherein the instructions are essentially based on the evaluations of the measured data. Preferably, such a computer program also automatically controls the operation. Preferably, the force range is changed manually by the specialist staff and then regulated automatically in the corresponding range. The evaluation of the work output or performance by the test person is very concise since in the present invention friction loss has been minimized to a negligible value. Friction losses can essentially be avoided by providing a cushion, preferably an air cushion, in the piston/cylinder array between the piston and the cylinder at least during relative motion. All the components used in the ergometer were examined for their suitability in an MR apparatus, and the ergometer preferably consists of non-ferromagnetic materials, such as e.g. plastics or wood, and was furthermore only processed with tools which do not cause metal abrasion on the individual components. -3- The resistance, or the force, that has to be overcome or applied at the drive means to set it in motion is generated by a pneumatic system in the sense of a piston/cylinder system. In addition to compressed air, which is preferred, fluids of all kinds can be used. Preferably, compressible fluids are used. The piston is constructed such that a narrow air cushion forms between the piston and the cylinder which diminishes friction to such a degree that it is negligible in the calculation of the work output. An air vessel is provided between a compressed air inlet and the cylinder so that air pressure can be controlled or regulated infinitely at any time, even during the measurement. A computer-controlled control system is preferably used for this purpose, which is operated outside of the MR apparatus forming the Faraday cage. Thus, no electronic device is present inside or close to the MR tube in order not to affect the measuring results. The control module comprises a pressure sensor and a pressure regulator as well as a computer with the appropriate software. The work output of the exercising muscles can be regulated in particular by the pressure in the cylinder, the depth of the piston's submergence into the cylinder and the frequency of the plantar flexion. The actual depth of the piston's submergence into the cylinder is measured; this will be explained in more detail in the description of the embodiments. The frequency is given by a metronome which provides different frequencies, whereby the test person or patient should follow the beat of the metronome when operating the ergometer. In addition to the frequency and the air pressure, the depth of the piston's submergence into the cylinder is also preferably infinitely variable. An appropriate program calculates the various parameters at a desired work output in watt or the watt number based on set parameters. -4- In another preferred embodiment of the ergometer as a pedal ergometer, the test person or patient preferably lies on his/her back during the measurement with his/her foot attached to a pedal with two straps. Furthermore, additional strap fixations are provided in the calf area and the shoulders in order to avoid motion artefacts. The fixation of the upper body can be adjusted to the height of the patient so that plantar flexion can be carried out to a pre-set stop and a full extension of the knee joint, respectively. A measuring coil is placed directly under the muscle or muscle group to be measured, preferably the muscles of the calf. In order to optimize the measuring result, the calf is placed in the middle of the measuring coil so that the distance between calf and measuring coil is minimized. Preferably, only one calf is measured in order to make use of the intensity of the measured signal in the center underneath the calf and thus reduce the measuring time. This is furthermore advantageous because no measuring artefacts from a second calf affect the result. Another preferred embodiment of the ergometer is an arm ergometer wherein the mechanism of the arm ergometer corresponds to that of the pedal ergometer. Instead of leg muscles, the arm muscle to be measured, e.g. the brachial or the antebrachial muscle, is placed in an appropriate position relative to the measuring device. In this embodiment, the test person or patient can be in a standing, sitting or lying position. In the following, the invention will be described based on exemplary preferred embodiments with reference to the drawings. Fig. 1 shows a schematic view of an embodiment of the device according to the present invention, -5- Fig. 2a shows a schematic view of an embodiment of the piston/cylinder array of the device according to the present invention, Fig. 2b shows a schematic sectional view of an embodiment of the piston/cylinder array of the device according to the present invention and Fig. 3 shows a schematic view of an embodiment of measuring the distance by means of a rotation angle wheel and a bending beam of the device of according to the present invention. Figure 1 shows a schematic perspective view of a preferred embodiment of an ergometer as a pedal ergometer 1. The components of the ergometer 1 consist of non-ferromagnetic materials so as to allow a use of the ergometer in an MR apparatus. On a base plate 2, a drive means, which in this preferred embodiment as a pedal ergometer is a pedal 3, is essentially movably provided with a fixture 5 via one or a pair of bearing pins 4, wherein the fixture 5 is firmly attached to the base plate 2. The drive means varies according to the body part to be measured, or the muscle(s) to be exercised, and is preferably designed such that when the drive means is deflected, the muscle to be measured or examined has to be exercised. For instance, the drive means can be designed such that essentially the desired muscles or muscle groups are exercised with known exercises such as e.g. butterfly, bench pressing, biceps curls, latissimus pull-down, leg extension, leg curl, leg adduction, leg press and/or cable cross. Thus, other embodiments of the drive means are e.g. handles, loops and other devices known from weight training. Preferably, the muscle to be measured essentially lies still on the measuring unit or measuring coil. For example, in the case of the pedal ergometer, the pedal 3 is therefore operated from the ankle joint in order to keep the calf as still as possible on top of the measuring coil. The drive means can -6- preferably be attached on-center to a body part of a test person or patient to be measured so that the results supplied by the measuring coil provided in the measuring coil holder 6 are as concise as possible. A pneumatic piston/cylinder array 7 is provided between the drive means, such as e.g. the pedal 3, and a fixture on the base plate 2 such that when the drive means is deflected by a test person or a patient, the piston 20 moves relative to the cylinder 21. The pneumatically applied pressure of the piston/cylinder array 7 constitutes a resistance or force when the test person or patient operates the pedal 3. The pedal 3 preferably comprises a stop which protects the piston 20 from knocking against the bottom of the cylinder 21. This way, damage to the piston/cylinder array 7 can be prevented. In another preferred embodiment of the ergometer according to the present invention as an arm ergometer, the ergometer is operated with muscles of the arm to be measured. The muscle(s) to be measured are positioned in a manner analogous to that described in connection with the pedal ergometer. The pneumatically applied pressure of the piston/cylinder array 7 is supplied from a compressed air inlet connected to the cylinder 21. Preferably, an air vessel 8 is provided between the ergometer 1 and the compressed air inlet. This air vessel 8 is designed such that the air pressure applied at the piston/cylinder array 7 can be controlled or regulated via a control means, which will be explained in more detail below, and furthermore guarantees that no high or short-term load peaks result from the counter-pressure when the drive means, e.g. the pedal 3, is deflected. The force to be applied is in a range of from 50 N to 900 N, or from 100 N to 800 N, or from 200 N to 700 N, or from 300 N to 600 N and is preferably about 600 N for healthy test persons and about 300 N for patients whose movement of the body part in question is restricted. -7- The ergometer 1 preferably comprises a control means whose sensors and accompanying protected cables can be provided within the examination chamber of the magnetic resonance apparatus. The electronic controls of the control means are located outside of the examination chamber of the magnetic resonance apparatus. The control means regulates the air pressure at the piston/cylinder array 7 and thus the pressure exerted onto the piston 20 which constitutes the force necessary to be applied by a test person or patient in order to deflect the drive means, e.g. the pedal 3. This control means preferably comprises a computer and a computer program for controlling and/or processing acquired data. The determination of the force to be applied at the drive means is carried out by one or several sensors provided at the piston 20 which convert a mechanical deformation to an electric signal or an electric resistance change. Preferably, a strain indicator 23 is used for this purpose. In the area of a strain indicator, the diameter of the piston 20 of the piston/cylinder array 7 is smaller than in the cylinder guidance. Furthermore, at least in the area of the strain indicator, the piston 20 can be hollow. In a preferred embodiment, the modulus of elasticity of the piston 20 is ideally 3,000 N/mm2. The resistance or force necessary to set the drive means or the pedal 3 in motion can be controlled or regulated in particular during operation. The resistance or force can be automatically or electronically regulated or e.g. controlled manually based on the signals measured during the examination of the test person or patient. Furthermore, the piston 20 and the cylinder 21 are sized such that an air cushion is formed between them at least during operation or when they move relative to each other. Due to this air cushion, the -8- frictional resistance becomes negligible and consequently, the measured values are considerably more precise. The piston/cylinder array 7 comprises a gap between the piston 20 and the cylinder 21 of 0.02 mm to 0.05 mm, or 0.03 mm to 0.05 mm, or 0.02 mm to 0.04 mm, or 0.03 to 0.04 mm, and preferably the gap is about 0.035 mm. Furthermore, in a preferred embodiment as pedal ergometer fixations are provided, such as e.g. a strap fixation for the test person's foot, calf and shoulders, which can also be adjusted to the height of the test person or patient. In another preferred embodiment as an arm ergometer, corresponding fixations are provided e.g. for the hand or forearm of the test person or patient. For measuring the distance of the motion of the drive means, a carbon spring comprising at least one strain indicator is provided parallel to the pneumatic cylinder 21. This way, conclusions can be drawn regarding the motion of the drive means, e.g. the pedaling motion, as a function of the output signal of the strain indicator. This carbon spring is designed such that it exhibits a spring constant over a long spring travel, and the spring is operated in this range of the spring travel. Figure 2a shows a schematic view of a piston/cylinder array 7, and Figure 2b shows a sectional view of this piston/cylinder array 7. By means of an adapter 22, the force range to be applied by the test person or patient can be modified in the ranges described above, preferably depending on whether a patient or a test person is examined. This is done by firmly attaching the piston diameter effective in the cylinder either to the cylinder 21 or the piston 20 using an adapter 22 which -9- encircles the piston 20. Preferably, the adapter 22 is screwed to the part at issue. Figure 3 shows the measuring of the distance by means of a rotation angle wheel 32 and a bending beam 31. When the drive means is deflected, the bending beam 31 is deflected and the distance traveled by the drive means is determined. For this purpose, the rotation angle wheel 32 is attached to an eccentric rotating pin 34 used as an axis, and the rotation angle wheel 32 is moved as a consequence of the deflection of the drive means, e.g. the pedal 3, and in turn deflects the bending beam 31. Thus, the bending beam 31, whose one end is firmly attached to a fixing device 30, is deflected. At least one strain indicator 33 is provided at the bending beam 31 such that the deformation of the bending beam 31 is converted to an electronic signal. The invention also encompasses embodiments combining features from different embodiments described above. -10- constitutes a resistance or force for deflecting the drive means by the test person or patient, characterized in that the piston (20) and the cylinder (21) are sized such that an air cushion is formed between them at least during operation or when they move relative to each other. 3. Ergometer according to claim 1 or 2, wherein the drive means is a pedal (3) or a handle. 4. Ergometer according to claim 3, wherein the ergometer furthermore comprises strap fixations for the foot, calf, and shoulders of a test person or patient. 5. Ergometer according to claim 3 or 4, wherein the strap fixation for the shoulders can be adjusted to the height of the test person. 6. Ergometer according to any of the preceding claims, wherein the piston/cylinder array (7) comprises a gap of at least 0.02 mm and at most 0.05 mm between the piston (20) and the cylinder (21). 7. Ergometer according to any of the preceding claims, wherein the components of the ergometer consist of non- ferromagnetic materials. 8. Ergometer according to any of the preceding claims, wherein the drive means comprises a stop which protects the piston (20) from knocking against the bottom of the cylinder (21). -12- 9. Ergometer according to any of the preceding claims, wherein the force to be applied at the drive means is determined via the measurement of the air pressure in the cylinder (21) or in the compressed air inlet. 10. Ergometer according to any of the preceding claims, wherein the force to be applied at the drive means is determined via at least one strain indicator at the piston. 11. Ergometer according to claim 10, wherein in the area of the strain indicator the diameter of the piston is smaller than in the cylinder guidance. 12. Ergometer according to claim 10, wherein the piston (20) is hollow at least in the area of the strain indicator. 13. Ergometer according to any of the preceding claims, wherein the modulus of. elasticity of the piston (20) is ideally 3,000 N/mm2. 14. Ergometer according to any of the preceding claims, wherein the measurement of the distance of the motion of the drive means is carried out with a carbon spring comprising at least one strain indicator which is provided parallel to the pneumatic cylinder. 15. Ergometer according to claim 14, wherein the carbon spring is designed such that it exhibits a spring constant over a long spring travel and the spring is operated in this range. 16. Ergometer according to any of the preceding claims, wherein the distance is determined by means of a bending -13- beam (31) which -is deflected by the motion of the drive means. 17. Ergometer according to claim 16, wherein a rotation angle wheel (32) is firmly attached to an eccentric rotating pin (34) used as an axis and provided such that it is moved as a consequence of the deflection of the drive means and in turn deflects the bending beam (31) . 18. Ergometer according to claim 16 or 17, wherein one end of the bending beam (31) is firmly attached by means of a fixing device (30) and is deflected at a distance thereto. 19. Ergometer according to claim 16, 17 or 18, wherein at least one strain indicator (33) is provided at the bending beam (31) such that the deformation of the bending beam (31) is converted to an electronic signal. 20. Ergometer according to any of the preceding claims, wherein the drive means is attached on-center to a body part of a test person or patient to be measured.- 21. Ergometer according to any of the preceding claims, wherein the force to be applied by the •test person or patient is modified by modifying the piston diameter effective in the cylinder (21) by means of an adapter (23) encircling the piston (20) which is attached to either the cylinder (21) or the piston (20). 22. Ergometer according to any of the preceding claims, wherein the force to be applied at the drive means is up to about 600 N for healthy test persons and ideally about 300 N for patients. -14- 23. Ergometer arrangement comprising an ergometer according to any of the preceding claims, wherein the arrangement furthermore comprises a compressed air inlet and an air vessel (8) provided between the compressed air inlet and the ergometer. 24. Ergometer arrangement comprising an ergometer according to claim 23, wherein the air vessel (8) is designed such that the air pressure applied at the piston/cylinder array (7) can be controlled or regulated and guarantees that no high or short-term load peaks result from the counter-pressure when the drive means is deflected. 25. Ergometer arrangement according to claim 23 or 24, wherein the arrangement furthermore comprises a control means whose sensors and accompanying protected cables are provided within the examination chamber of the magnetic resonance apparatus and the electronic controls of the control means are located outside of the examination chamber of the magnetic resonance apparatus. 26. Ergometer arrangement according to claim 25, wherein the control means regulates the air pressure at the piston/cylinder array {7) and thus the pressure exerted onto the piston (20) which constitutes the force necessary to be applied by a test person or patient in order to deflect the drive means. 27. Ergometer arrangement according to claim 25 or 26, wherein the control means comprises a computer and a computer program for controlling and/or processing acquired data. -15- 28. Process for operating.an ergometer, in particular according to claim 1 or 7, in a magnetic resonance apparatus, comprising the steps: providing at least one movable drive means, providing at least one pneumatic piston/cylinder array (7) comprising arranging the drive means at the piston (20) or the cylinder (21) and creating a resistance or force to be overcome by the test person or patient by operating the drive means and providing pneumatically applied pressure between the piston (20) and the cylinder (21), characterized by controlling and/or regulating the resistance or force necessary to set the drive means in motion, particularly during operation, wherein the step of regulating or controlling the resistance or the force is automatically or electronically, based on measured signals from a feedback loop during the examination of the test person or patient. 29. Process for operating an ergometer in particular according to any of claims 2, 6 or 7, in a magnetic resonance apparatus, comprising the steps: providing at least one movable drive means, providing at least one pneumatic piston/cylinder array (7) comprising arranging the drive means at the piston (20) or the cylinder (21) and creating a resistance or force to be overcome by the test person or patient by operating the drive means and providing pneumatically applied pressure between the piston (20) and the cylinder (21), -16- characterized by forming an air cushion between the piston (20) and the cylinder (21) during operation or when they move relative to each other. 30. Use of an ergometer, an ergometer arrangement and/or a process according to any of the preceding claims in medical diagnostics and sports science, in particular for a P NMR process. -17- The present invention relates to an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. It comprises at least one drive means which is provided essentially movably and at least one pneumatic piston/cylinder array (7). The drive means is provided at the piston (20) or the cylinder (21) and pneumatically applied pressure between the piston (20) and the cylinder (21) constitutes a resistance or force to be overcome by the test person or patient by operating the drive means. The resistance or the force necessary to set the drive means in motion, particularly during operation, can be controlled and/or regulated and the piston (20) and the cylinder (21) are sized such that an air cushion is formed between them at least during operation or when they move relative to each other. The resistance or the force necessary to operate the drive means is regulated and/or controlled automatically or electronically based on measured signals from a feedback loop during the examination of the test person or patient.

Full Text

Our Ref.: L 1520 PCT
Ergometer suitable for use in a
magnetic resonance apparatus
The present invention relates to an ergometer and a process
for operating an ergometer which is particularly suitable for
examining a test person or patient in a magnetic resonance
(MR) apparatus. Such examinations are carried out, inter
alia, in the fields of medical diagnostics and sports science.
Exercising different muscle groups is a frequently used method
to examine muscle function in the fields of sports medicine
and cardiovascular medicine. What is referred to as the 31P-
MRS process (Phosphorus-31 Nuclear Magnetic Resonance
Spectroscopy) is a suitable examination process wherein the
blood flow in a stimulated muscle is measured locally in a
magnetic resonance apparatus. This way, energy metabolites in
the muscle, such as for example phosphocreatine, inorganic
phosphate or adenosine triphosphate, can be measured
quantitatively. By means of the 31P-MRS process it is also
possible to record the energy metabolites when exercising the
muscles of the calf. Initially, there is a decrease in
phosphocreatine when the muscle is exercised to a certain
degree until the oxygen supply in the muscle is raised to such
an extent that the increased energy requirements can be met by
the oxidative metabolism alone. In that case, the
phosphocreatine breakdown reaches an equilibrium state. If
due to a stenosis in a supplying blood vessel the blood flow
and thus the oxygen supply cannot be increased to meet the
demand, the phosphocreatine decreases progressively.
The use of an ergometer in a strong magnetic field is
problematic since many components have to be manufactured from
- 1 -

non-ferromagnetic metals and/or wood or plastic materials so
that the device can be operated in an artefact-free manner and
will function correctly, e.g. in a magnetic resonance
tomograph. Also, sensors and cables for measuring device
parameters such as force and travel have to be provided such
that they do not cause measuring artefacts. Furthermore, it
has to be possible to set a defined and reproducible force, or
resistance, in an ergometer which has to be overcome by a test
person or patient to set a drive means, which can e.g. be a
pedal, in motion. Furthermore, it is useful if during
ergometry the work output can be set, measured, or calculated,
and adjusted accordingly while the ergometer is operated.
When using an ergometer, the test person or patient presses
against a defined resistance at a set frequency, with the
deflection angle of the pedal and friction playing an
important role as well. The frequency is usually given by a
metronome and the force is measured by means of piezo
technology. In commercially available ergometers which are
operated outside of magnetic fields, the force setting is
automatically readjusted via a feedback control system by
means of suitable electronic or mechanic devices during the
operation if the test person does not maintain the frequency
or angle deflection. The use of an ergometer only makes sense
if such feedback control systems are in place. The ergometers
suitable for use in an MR apparatus which are currently
commercially available do not comprise such a feedback control
system. Moreover, in the commercially available ergometers
the measuring result is falsified in a non-linear manner due
to frictional resistance during the motion of the drive means
so that a measuring error cannot be calculated reliably.
It is therefore the object of the present invention to provide
an improved ergometer, and/or an improved ergometer
arrangement, which preferably overcomes the disadvantages
described above.
-2-

This object is achieved by the features described in the
patent claims.
The invention is based on the fundamental idea of providing an
ergometer which is particularly suitable for examining a test
person or patient in a magnetic resonance apparatus. The test
person or patient has to apply a certain force, which can be
pre-set, at a drive means in order to set a piston/cylinder
array in motion. This essentially causes the piston and the
cylinder to move relative to each other. The force necessary
to overcome the resistance presented by the piston/cylinder
array can be controlled or regulated, in particular during the
motion of the drive means. This can be done manually by
specialist staff or with the help of appropriate instructions
e.g. from an instructing computer program wherein the
instructions are essentially based on the evaluations of the
measured data. Preferably, such a computer program also
automatically controls the operation. Preferably, the force
range is changed manually by the specialist staff and then
regulated automatically in the corresponding range. The
evaluation of the work output or performance by the test
person is very concise since in the present invention friction
loss has been minimized to a negligible value. Friction
losses can essentially be avoided by providing a cushion,
preferably an air cushion, in the piston/cylinder array
between the piston and the cylinder at least during relative
motion.
All the components used in the ergometer were examined for
their suitability in an MR apparatus, and the ergometer
preferably consists of non-ferromagnetic materials, such as
e.g. plastics or wood, and was furthermore only processed with
tools which do not cause metal abrasion on the individual
components.
-3-

The resistance, or the force, that has to be overcome or
applied at the drive means to set it in motion is generated by
a pneumatic system in the sense of a piston/cylinder system.
In addition to compressed air, which is preferred, fluids of
all kinds can be used. Preferably, compressible fluids are
used. The piston is constructed such that a narrow air
cushion forms between the piston and the cylinder which
diminishes friction to such a degree that it is negligible in
the calculation of the work output. An air vessel is provided
between a compressed air inlet and the cylinder so that air
pressure can be controlled or regulated infinitely at any
time, even during the measurement. A computer-controlled
control system is preferably used for this purpose, which is
operated outside of the MR apparatus forming the Faraday cage.
Thus, no electronic device is present inside or close to the
MR tube in order not to affect the measuring results. The
control module comprises a pressure sensor and a pressure
regulator as well as a computer with the appropriate software.
The work output of the exercising muscles can be regulated in
particular by the pressure in the cylinder, the depth of the
piston's submergence into the cylinder and the frequency of
the plantar flexion. The actual depth of the piston's
submergence into the cylinder is measured; this will be
explained in more detail in the description of the
embodiments. The frequency is given by a metronome which
provides different frequencies, whereby the test person or
patient should follow the beat of the metronome when operating
the ergometer. In addition to the frequency and the air
pressure, the depth of the piston's submergence into the
cylinder is also preferably infinitely variable. An
appropriate program calculates the various parameters at a
desired work output in watt or the watt number based on set
parameters.
-4-

In another preferred embodiment of the ergometer as a pedal
ergometer, the test person or patient preferably lies on
his/her back during the measurement with his/her foot attached
to a pedal with two straps. Furthermore, additional strap
fixations are provided in the calf area and the shoulders in
order to avoid motion artefacts. The fixation of the upper
body can be adjusted to the height of the patient so that
plantar flexion can be carried out to a pre-set stop and a
full extension of the knee joint, respectively. A measuring
coil is placed directly under the muscle or muscle group to be
measured, preferably the muscles of the calf. In order to
optimize the measuring result, the calf is placed in the
middle of the measuring coil so that the distance between calf
and measuring coil is minimized. Preferably, only one calf is
measured in order to make use of the intensity of the measured
signal in the center underneath the calf and thus reduce the
measuring time. This is furthermore advantageous because no
measuring artefacts from a second calf affect the result.
Another preferred embodiment of the ergometer is an arm
ergometer wherein the mechanism of the arm ergometer
corresponds to that of the pedal ergometer. Instead of leg
muscles, the arm muscle to be measured, e.g. the brachial or
the antebrachial muscle, is placed in an appropriate position
relative to the measuring device. In this embodiment, the
test person or patient can be in a standing, sitting or lying
position.
In the following, the invention will be described based on
exemplary preferred embodiments with reference to the
drawings.
Fig. 1 shows a schematic view of an embodiment of the device
according to the present invention,
-5-

Fig. 2a shows a schematic view of an embodiment of the
piston/cylinder array of the device according to the
present invention,
Fig. 2b shows a schematic sectional view of an embodiment of
the piston/cylinder array of the device according to
the present invention and
Fig. 3 shows a schematic view of an embodiment of measuring
the distance by means of a rotation angle wheel and a
bending beam of the device of according to the
present invention.
Figure 1 shows a schematic perspective view of a preferred
embodiment of an ergometer as a pedal ergometer 1. The
components of the ergometer 1 consist of non-ferromagnetic
materials so as to allow a use of the ergometer in an MR
apparatus. On a base plate 2, a drive means, which in this
preferred embodiment as a pedal ergometer is a pedal 3, is
essentially movably provided with a fixture 5 via one or a
pair of bearing pins 4, wherein the fixture 5 is firmly
attached to the base plate 2. The drive means varies
according to the body part to be measured, or the muscle(s) to
be exercised, and is preferably designed such that when the
drive means is deflected, the muscle to be measured or
examined has to be exercised. For instance, the drive means
can be designed such that essentially the desired muscles or
muscle groups are exercised with known exercises such as e.g.
butterfly, bench pressing, biceps curls, latissimus pull-down,
leg extension, leg curl, leg adduction, leg press and/or cable
cross. Thus, other embodiments of the drive means are e.g.
handles, loops and other devices known from weight training.
Preferably, the muscle to be measured essentially lies still
on the measuring unit or measuring coil. For example, in the
case of the pedal ergometer, the pedal 3 is therefore operated
from the ankle joint in order to keep the calf as still as
possible on top of the measuring coil. The drive means can
-6-

preferably be attached on-center to a body part of a test
person or patient to be measured so that the results supplied
by the measuring coil provided in the measuring coil holder 6
are as concise as possible. A pneumatic piston/cylinder array
7 is provided between the drive means, such as e.g. the pedal
3, and a fixture on the base plate 2 such that when the drive
means is deflected by a test person or a patient, the piston
20 moves relative to the cylinder 21. The pneumatically
applied pressure of the piston/cylinder array 7 constitutes a
resistance or force when the test person or patient operates
the pedal 3. The pedal 3 preferably comprises a stop which
protects the piston 20 from knocking against the bottom of the
cylinder 21. This way, damage to the piston/cylinder array 7
can be prevented.
In another preferred embodiment of the ergometer according to
the present invention as an arm ergometer, the ergometer is
operated with muscles of the arm to be measured. The
muscle(s) to be measured are positioned in a manner analogous
to that described in connection with the pedal ergometer.
The pneumatically applied pressure of the piston/cylinder
array 7 is supplied from a compressed air inlet connected to
the cylinder 21. Preferably, an air vessel 8 is provided
between the ergometer 1 and the compressed air inlet. This
air vessel 8 is designed such that the air pressure applied at
the piston/cylinder array 7 can be controlled or regulated via
a control means, which will be explained in more detail below,
and furthermore guarantees that no high or short-term load
peaks result from the counter-pressure when the drive means,
e.g. the pedal 3, is deflected. The force to be applied is in
a range of from 50 N to 900 N, or from 100 N to 800 N, or from
200 N to 700 N, or from 300 N to 600 N and is preferably about
600 N for healthy test persons and about 300 N for patients
whose movement of the body part in question is restricted.
-7-

The ergometer 1 preferably comprises a control means whose
sensors and accompanying protected cables can be provided
within the examination chamber of the magnetic resonance
apparatus. The electronic controls of the control means are
located outside of the examination chamber of the magnetic
resonance apparatus. The control means regulates the air
pressure at the piston/cylinder array 7 and thus the pressure
exerted onto the piston 20 which constitutes the force
necessary to be applied by a test person or patient in order
to deflect the drive means, e.g. the pedal 3. This control
means preferably comprises a computer and a computer program
for controlling and/or processing acquired data.
The determination of the force to be applied at the drive
means is carried out by one or several sensors provided at the
piston 20 which convert a mechanical deformation to an
electric signal or an electric resistance change. Preferably,
a strain indicator 23 is used for this purpose. In the area
of a strain indicator, the diameter of the piston 20 of the
piston/cylinder array 7 is smaller than in the cylinder
guidance. Furthermore, at least in the area of the strain
indicator, the piston 20 can be hollow. In a preferred
embodiment, the modulus of elasticity of the piston 20 is
ideally 3,000 N/mm2.
The resistance or force necessary to set the drive means or
the pedal 3 in motion can be controlled or regulated in
particular during operation. The resistance or force can be
automatically or electronically regulated or e.g. controlled
manually based on the signals measured during the examination
of the test person or patient. Furthermore, the piston 20 and
the cylinder 21 are sized such that an air cushion is formed
between them at least during operation or when they move
relative to each other. Due to this air cushion, the
-8-

frictional resistance becomes negligible and consequently, the
measured values are considerably more precise. The
piston/cylinder array 7 comprises a gap between the piston 20
and the cylinder 21 of 0.02 mm to 0.05 mm, or 0.03 mm to 0.05
mm, or 0.02 mm to 0.04 mm, or 0.03 to 0.04 mm, and preferably
the gap is about 0.035 mm.
Furthermore, in a preferred embodiment as pedal ergometer
fixations are provided, such as e.g. a strap fixation for the
test person's foot, calf and shoulders, which can also be
adjusted to the height of the test person or patient.
In another preferred embodiment as an arm ergometer,
corresponding fixations are provided e.g. for the hand or
forearm of the test person or patient.
For measuring the distance of the motion of the drive means, a
carbon spring comprising at least one strain indicator is
provided parallel to the pneumatic cylinder 21. This way,
conclusions can be drawn regarding the motion of the drive
means, e.g. the pedaling motion, as a function of the output
signal of the strain indicator. This carbon spring is
designed such that it exhibits a spring constant over a long
spring travel, and the spring is operated in this range of the
spring travel.
Figure 2a shows a schematic view of a piston/cylinder array 7,
and Figure 2b shows a sectional view of this piston/cylinder
array 7. By means of an adapter 22, the force range to be
applied by the test person or patient can be modified in the
ranges described above, preferably depending on whether a
patient or a test person is examined. This is done by firmly
attaching the piston diameter effective in the cylinder either
to the cylinder 21 or the piston 20 using an adapter 22 which
-9-

encircles the piston 20. Preferably, the adapter 22 is
screwed to the part at issue.
Figure 3 shows the measuring of the distance by means of a
rotation angle wheel 32 and a bending beam 31. When the drive
means is deflected, the bending beam 31 is deflected and the
distance traveled by the drive means is determined. For this
purpose, the rotation angle wheel 32 is attached to an
eccentric rotating pin 34 used as an axis, and the rotation
angle wheel 32 is moved as a consequence of the deflection of
the drive means, e.g. the pedal 3, and in turn deflects the
bending beam 31. Thus, the bending beam 31, whose one end is
firmly attached to a fixing device 30, is deflected. At least
one strain indicator 33 is provided at the bending beam 31
such that the deformation of the bending beam 31 is converted
to an electronic signal.
The invention also encompasses embodiments combining features
from different embodiments described above.
-10-

constitutes a resistance or force for deflecting the drive
means by the test person or patient,
characterized in that
the piston (20) and the cylinder (21) are sized such that
an air cushion is formed between them at least during
operation or when they move relative to each other.
3. Ergometer according to claim 1 or 2,
wherein the drive means is a pedal (3) or a handle.
4. Ergometer according to claim 3, wherein the ergometer
furthermore comprises strap fixations for the foot, calf,
and shoulders of a test person or patient.
5. Ergometer according to claim 3 or 4,
wherein the strap fixation for the shoulders can be
adjusted to the height of the test person.
6. Ergometer according to any of the preceding claims,
wherein the piston/cylinder array (7) comprises a gap of
at least 0.02 mm and at most 0.05 mm between the piston
(20) and the cylinder (21).
7. Ergometer according to any of the preceding claims,
wherein the components of the ergometer consist of non-
ferromagnetic materials.
8. Ergometer according to any of the preceding claims,
wherein the drive means comprises a stop which protects
the piston (20) from knocking against the bottom of the
cylinder (21).
-12-

9. Ergometer according to any of the preceding claims,
wherein the force to be applied at the drive means is
determined via the measurement of the air pressure in the
cylinder (21) or in the compressed air inlet.
10. Ergometer according to any of the preceding claims,
wherein the force to be applied at the drive means is
determined via at least one strain indicator at the
piston.
11. Ergometer according to claim 10,
wherein in the area of the strain indicator the diameter
of the piston is smaller than in the cylinder guidance.
12. Ergometer according to claim 10,
wherein the piston (20) is hollow at least in the area of
the strain indicator.
13. Ergometer according to any of the preceding claims,
wherein the modulus of. elasticity of the piston (20) is
ideally 3,000 N/mm2.
14. Ergometer according to any of the preceding claims,
wherein the measurement of the distance of the motion of
the drive means is carried out with a carbon spring
comprising at least one strain indicator which is provided
parallel to the pneumatic cylinder.
15. Ergometer according to claim 14, wherein the carbon spring
is designed such that it exhibits a spring constant over a
long spring travel and the spring is operated in this
range.
16. Ergometer according to any of the preceding claims,
wherein the distance is determined by means of a bending
-13-

beam (31) which -is deflected by the motion of the drive
means.
17. Ergometer according to claim 16, wherein a rotation angle
wheel (32) is firmly attached to an eccentric rotating pin
(34) used as an axis and provided such that it is moved as
a consequence of the deflection of the drive means and in
turn deflects the bending beam (31) .
18. Ergometer according to claim 16 or 17, wherein one end of
the bending beam (31) is firmly attached by means of a
fixing device (30) and is deflected at a distance thereto.
19. Ergometer according to claim 16, 17 or 18, wherein at
least one strain indicator (33) is provided at the bending
beam (31) such that the deformation of the bending beam
(31) is converted to an electronic signal.
20. Ergometer according to any of the preceding claims,
wherein the drive means is attached on-center to a body
part of a test person or patient to be measured.-
21. Ergometer according to any of the preceding claims,
wherein the force to be applied by the •test person or
patient is modified by modifying the piston diameter
effective in the cylinder (21) by means of an adapter (23)
encircling the piston (20) which is attached to either the
cylinder (21) or the piston (20).
22. Ergometer according to any of the preceding claims,
wherein the force to be applied at the drive means is up
to about 600 N for healthy test persons and ideally about
300 N for patients.
-14-

23. Ergometer arrangement comprising an ergometer according to
any of the preceding claims,
wherein the arrangement furthermore comprises a compressed
air inlet and an air vessel (8) provided between the
compressed air inlet and the ergometer.
24. Ergometer arrangement comprising an ergometer according to
claim 23,
wherein the air vessel (8) is designed such that the air
pressure applied at the piston/cylinder array (7) can be
controlled or regulated and guarantees that no high or
short-term load peaks result from the counter-pressure
when the drive means is deflected.
25. Ergometer arrangement according to claim 23 or 24,
wherein the arrangement furthermore comprises a control
means whose sensors and accompanying protected cables are
provided within the examination chamber of the magnetic
resonance apparatus and the electronic controls of the
control means are located outside of the examination
chamber of the magnetic resonance apparatus.
26. Ergometer arrangement according to claim 25,
wherein the control means regulates the air pressure at
the piston/cylinder array {7) and thus the pressure
exerted onto the piston (20) which constitutes the force
necessary to be applied by a test person or patient in
order to deflect the drive means.
27. Ergometer arrangement according to claim 25 or 26, wherein
the control means comprises a computer and a computer
program for controlling and/or processing acquired data.
-15-

28. Process for operating.an ergometer,
in particular according to claim 1 or 7, in a magnetic
resonance apparatus, comprising the steps:
providing at least one movable drive means,
providing at least one pneumatic piston/cylinder array (7)
comprising arranging the drive means at the piston (20) or
the cylinder (21) and creating a resistance or force to be
overcome by the test person or patient by operating the
drive means and providing pneumatically applied pressure
between the piston (20) and the cylinder (21),
characterized by
controlling and/or regulating the resistance or force
necessary to set the drive means in motion, particularly
during operation, wherein the step of regulating or
controlling the resistance or the force is automatically
or electronically, based on measured signals from a
feedback loop during the examination of the test person or
patient.
29. Process for operating an ergometer
in particular according to any of claims 2, 6 or 7, in a
magnetic resonance apparatus, comprising the steps:
providing at least one movable drive means,
providing at least one pneumatic piston/cylinder array (7)
comprising arranging the drive means at the piston (20) or
the cylinder (21) and creating a resistance or force to be
overcome by the test person or patient by operating the
drive means and providing pneumatically applied pressure
between the piston (20) and the cylinder (21),
-16-

characterized by
forming an air cushion between the piston (20) and the
cylinder (21) during operation or when they move relative
to each other.
30. Use of an ergometer, an ergometer arrangement and/or a
process according to any of the preceding claims in
medical diagnostics and sports science, in particular for
a P NMR process.
-17-

The present invention relates to an ergometer which is particularly suitable for examining a test person or patient in a magnetic resonance apparatus. It comprises at least one drive means which is provided essentially movably and at least one pneumatic piston/cylinder array (7). The drive means is provided at the piston (20) or the cylinder (21) and pneumatically applied pressure between the piston (20) and the cylinder (21) constitutes a resistance or force to be overcome by the test person or patient by operating the drive means. The resistance or the force necessary to set the drive means in motion, particularly during operation, can be controlled and/or regulated and the piston (20) and the cylinder (21) are sized such that an air cushion is formed between them at least during operation or when they move relative to each other. The resistance or the force necessary to operate the drive means is regulated and/or controlled automatically or electronically based on measured signals from a feedback loop during the examination of the test person or patient.

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Patent Number

270222

Indian Patent Application Number

3947/KOLNP/2007

PG Journal Number

49/2015

Publication Date

04-Dec-2015

Grant Date

02-Dec-2015

Date of Filing

15-Oct-2007

Name of Patentee

GREINER, ANDREAS

Applicant Address

LARCHENSTRASSE 49A 6063 RUM

Inventors:

#	Inventor's Name	Inventor's Address
1	GREINER, ANDREAS	LARCHENSTRASSE 49A 6063 RUM
2	SCHOCKE, MICHAEL	OPPOLZERSTRASSE 6 6020 INNSBRUCK

PCT International Classification Number

A61B 5/22

PCT International Application Number

PCT/EP2006/003639

PCT International Filing date

2006-04-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	05008676.8	2005-04-20	EPO