Bereits 1999 war es möglich, mit einem speziell für Magnetresonanz-Untersuchungen hergestellten Ergometer Belastungen durchzuführen und die Herzaktion dann in “real-time” oder mittels EKG-Triggerung zu akquirieren. Leider hat die Industrie diese interessante Technologie nicht weiter verfolgt, was blieb, sind Adenosin-Belastungen, welche mitunter nicht sehr angenehm sind. Vielleicht erlebt ja das Exercise-Herz MRI ein Revival?
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As early as 1999, it was possible to use an ergometer specially manufactured for magnetic resonance examinations to perform stress tests and then acquire the heart action in “real time” or by means of ECG triggering. Unfortunately, the industry did not pursue this interesting technology any further; what remained were adenosine stresses, which are sometimes not very pleasant. Perhaps the exercise heart MRI will experience a revival?
Background
Supine bicycle exercise testing within the magnet field? A challenging task, indeed. Is it feasable, realible and indicated?
Indication
Supine bicycle exercise testing outside the magnet field? We did that back in 2002 on a Philips 1.5 Tesla scanner in a patient with transient right ventricular dysfunction of unknown origing
Technique
Images were obtained without contrast media by real-time CMR imaging in short breath holds allowing for rapid acquisition of CMR images immediate post exercise. For that purpose, the patient was asked to stop pedaling and reentered into the bore of the magnet.
Results
Images were ungated and acquired by real time CMR. Image quality was absolutely sufficient to assess right and left ventricular function in the short axis. Performance of ventricles were hyperdynamic at a heart rate of about 130/min.
View the short axis images
Second case
We imaged a young 17 year old healthy man who consented to exercise with the CMR bicylce. Potential problems: No valuable ECG signal in case of ischemia
Measurements of blood pressure problematic
Obese patients are not suitable
Breath hold (10 sec for two slices or 32
images) may be too long in dyspneic patients
Arrhythmia is not compatible with imaging
View his short axis images
Conclusion
Exercise MRI is feasable, image quality is not hampered by ultrafast imaging or high heart rate.
Detection of endocardial borders is excellent
Quantification of left ventricular function
is possible and readily obtainable.
Exercising in the Magnet :-)
