Angiology and vascular medicine

How to assess ischemia on the exercising muscle?

Combining Ergospect modules currently available with existing MR technologies offers a wide range of clinical, scientific and pharmacological applications.

Clinical Applications
The symptoms of many diseases are only evident and can only be assessed during exercise. Static measurements are just a snapshot and do not reveal the entire physiological range of an organism. Relevant diseases and clinical pictures therefore require dynamic evaluation during load or movement in order to reveal symptoms. Ergospect offers a wide variety of possible applications and custom-made developments. Peripheral arterial disease (PAD) is a very common condition (Esterhammer 2008, Schocke 2008). Approximately 20% of people over 55 years of age suffer from PAD, which significantly compromises their quality of life. This often manifests in severe pain on walking even short distances. An accurate evaluation of muscle physiology is essential in order to treat these conditions. Methods employed to date are expensive and sometimes inappropriate. Thanks to the Ergospect pedal, muscle function can now be assessed accurately and optimum treatment can be recommended for the patient.

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Scientific Applications
Why does muscle fatigue occur during exercise and how can the onset of fatigue be delayed by appropriate training? One of the vital requirements in medical diagnostics and physiology is the precise knowledge and assessment of muscle metabolism. Until recently, muscle metabolism could only be assessed by a muscle biopsy – an invasive procedure whereby a small piece of muscle tissue is extracted from the subject (Febbraio 1999). This procedure can be expensive, time-consuming and potentially painful. With the Ergospect pedal, the muscle metabolism of athletes and amateur sportsmen alike can easily be assessed using a non-invasive technique and without using contrast agents (Pesta 2010). By adopting this approach, training progress can be evaluated easily, effectively and safely over extended periods of time. These possibilities open up new optimised training avenues and will prove indispensable in emerging fields.

Pharmacological Applications
Pharmaceutical companies can now evaluate the effects of new drugs using the diagnostic Ergospect pedal. This is a straightforward, non-invasive method for testing metabolic changes in different muscles and throughout the body. One key advantage of this technique is that the various muscle groups (M. gastrocnemius, M. gluteus, M., quadriceps femoris) can be examined independently.

Application Fields of Ergospect Modules

Trispect:

Functional Specification:

  • calf muscles, muscles of the planta pedis
Indications:
  • macrovascular disease, e.g. peripheral arterial disease (PAD), microvascular disease, e.g. diabetes mellitus (DM),
  • disorders of muscle metabolism (myopathies, lipid metabolism),
  • changes in lactate metabolism (cancer, diabetes mellitus(DM)),
  • tumour perfusion before, during and after chemotherapy,
  • tissue perfusion after transplantations, replantation, frostbite or drug application,
  • assessment of training progress in patients (e.g. peripheral arterial disease (PAD)),
  • exercise responses of athletes, amateur sportsmen and patients,
Parameters:
  • 31P MRS, 13C MRS: determination of mitochondrial function, anaerobic and aerobic capacity and glycogen metabolism
  • 1H-MRS: lipid metabolism and deoxymyoglobin: tracking of intra- and extra-myocellular lipids and myoglobin
  • LATEST: lactate chemical exchange saturation transfer (CEST) to image lactate in vivo
  • blood oxygen level dependency (BOLD): monitoring of the oxygen supply within the tissue (e.g. diabetes mellitus (DM))
  • perfusion MRI: microcirculation within the exercising muscle
  • phase-contrast MRI: assessment of blood flow
  • CINE MRI: real-time imaging of calf muscles during exercise testing
  • relaxometry: determination of oedema or water content in different tissues during exercise testing (calf muscles)
  • mfMRI: T2-imaging of the flexor muscles to determine intramuscular water content changes under strain
  • conventional loaded MRI: investigation of anatomical structures under isometric strain
Target:
  • angiologists, gerontologists, interventional radiologists, neurologists, orthopaedists, paediatricians, physiologists, plastic surgeons, radiologists, sports physicians, training facilities for astronauts and athletes, traumatologists, vascular physicians/surgeons
Cardio Step:

Functional Specification:

  • stress MRI of heart and circulation, cerebral blood flow
Indications:
  • coronary heart disease (CHD), myocardial infarction (MI),
  • evaluation of aortic (e.g. aortic aneurysms, aortic coarctation), coronary arterial, pulmonary and cerebral blood flow during exercise,
  • assessment of endothelial function of aorta, coronary arteries and internal mammary artery (IMA) during exercise with and without application of vasodilators,
  • assessment of training progress in patients (e.g. chronic obstructive pulmonary disease (COPD), peripheral arterial disease (PAD), chronic heart failure), athletes and amateur sports men,
  • exercise responses to gravity-independent training
Parameters:
  • 31P MRS, 13C MRS: determination of mitochondrial function, anaerobic and aerobic capacity and glycogen metabolism
  • 1H-MRS: lipid metabolism and deoxymyoglobin: tracking of intra- and extra-myocellular lipids and myoglobin
  • Functional MRI (fMRI) of the brain: inversion time (TI) pulsed arterial spin labelling (PASL): measurement of relative CBF before, during and after exercise
  • phase-contrast MRI: assessment of blood flow
  • relaxometry: determination of oedema or water content in the myocardium under stress
Target:
  • angiologists, cardiologists, gerontologists, heart surgeons, paediatricians, physiologists, pulmonologists, radiologists, sports physicians, training facilities for astronauts and athletes, vascular physicians/surgeons