Siemens exhibits new cardiac imaging application for aortic valve
prosthesis at ESC 2009
28 August 2009
Siemens will be demonstrating a new cardiac application for the syngo
DynaCT Cardiac imaging application at the ESC (European Society of
Cardiology) Congress 2009 from 30 Aug - 2 Sept.
During transfemoral aortic valve replacement, a heart valve
prosthesis gets implanted via peripheral artery access. To position
aortic valve prostheses accurately, the cardiologist must have very
precise knowledge of the individual anatomy of the patient’s aorta.
That's where syngo DynaCT Cardiac comes in: during the intervention,
it generates CT-like cross-sectional images on an angiographic C-arm
system and offers 3D reconstruction of the aortic root. These 3D images
can be overlaid on actual fluoroscopic images and provide a kind of
three-dimensional roadmap for the examiner. Thus, with syngo DynaCT
Cardiac, the cardiologist can position the valve prosthesis more
accurately and quickly than before.
For most patients worldwide, open heart surgery is performed for the
placement of an aortic valve prosthesis. The most frequent reason for
this intervention is the constriction of the valve, so-called aortic
valve stenosis, which occurs primarily in elderly persons.
In the course of time the valve loses elasticity and no longer fully
opens. This decreases the flow of blood, and the organs no longer
receive a sufficient supply of oxygen. Normally, the operation requires
opening the sternum. The heart has to be temporarily stopped and its
function taken over by a heart-lung machine. Especially for elderly and
severely ill patients with accompanying diseases such as heart failure,
renal failure and diabetes, such an intervention is risky.
Recently, new procedures have been developed in which the the aortic
valve prosthesis is implanted in the heart using a catheter rather than
through the usual open heart surgery. This involves an intervention
often performed jointly by the cardiologist and the heart surgeon.
First, through a small incision in the groin artery, a special balloon
catheter is guided to the heart to dialate the stenosed aortic valve.
Then, a collapsed heart valve is also inserted up to the valve level via
a balloon catheter; there it is unfolded and attached to the surrounding
tissue with a so-called "stent".
For such complex transcatheter techniques, high-performance
angiographic systems like those in the Siemens Artis zee family are
used, since they provide the best possible imaging, even in a completely
sterile OR environment. With these systems physicians can follow the
minimally invasive intervention on an X-ray screen while directly
monitoring the function of the valve prosthesis, which can possibly
spare the patient postoperative measures.
Prior to such interventions it is imperative that the cardiologist
gets a comprehensive picture of the heart and vessels. Previously, this
normally required imaging with CT scanners or MRI systems, which led to
additional costs.
For this reason, Siemens (as the first company in the medical field
in 2004) developed an application that can generate CT-like 3D images
directly on an angiography system: Syngo DynaCT.
The application has been continually fine-tuned and developed, so
that today it combines the advantages of three-dimensional CT imaging
with live X-ray imaging of the beating heart in one examination and on a
single system.
The CT-like images of the heart are produced by rotating the C-arm at
high speed around the patient. In this way, several hundred images are
acquired and reconstructed as 3D volumes. If the acquisition is
triggered via the patient ECG, even time-dependent 3D volumes can be
generated for visualization of the beating heart. The complete 3D image
is available in less than a minute.
Anatomical structure segments are overlaid with the live X-ray image,
allowing the physician to navigate with the catheter quickly and
confidently without the use of a contrast medium.
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