Latest applications for CT and low-dose scanning in clinical routine with Dual Source CT

At the Annual Scientific Meeting 2010 of the Society of Cardiovascular Computed Tomography (SSCT) in Las Vegas, Siemens will focus on Dual Source CT and show new applications in the fields of radiation dose and contrast agent reduction. Special emphasis will also be devoted to the planning of TAVI (Transcatheter Aortic Valve Implantation) procedures with the CT Scanner Somatom Definition Flash and the imaging software Syngo.via from Siemens. Leading cardiologists will show in workshops and symposia how they achieved progress in CT performance with the help of Siemens solutions.

Computed tomography angiography (CTA) has evolved into one of the most important methods in cardiac imaging in recent years. Particularly the Siemens scanner Somatom Definition Flash is, thanks to Dual Source CT, able to acquire full-volume images of the heart within seconds. That way, it allows cardiologists worldwide rapid advances in diagnosis and therapy of heart diseases. The Siemens scanner offers cardiologists many possibilities to further reduce radiation dose and contrast agent for CTAs. This is also one of the main objectives of the SCCT. Since 2006, the society has dedicated its annual meeting to the latest innovations in cardiac CT, offering an educational forum for cardiac specialists. Siemens provides knowledge for the cardiologists at the SCCT 2010 from July 15 to 17 in Las Vegas in a satellite symposium with many workshops and live case demonstrations.

CTA: Reduced dose in clinical routine with Dual Source CT

„Somatom Definition Flash enables us to significantly reduce CTA radiation dose in clinical routine into the sub-millisievert range for the vast majority of patients,” said Jörg Hausleiter, MD, cardiologist and Director of the Intensive Care Unit at the German Heart Center in Munich, Germany. Hausleiter and his colleagues have come to examine 60 to 70 percent of their patients with a radiation dose below one millisievert (mSv). The Siemens scanner enables them to display the entire heart volume within only one heart beat – independent of the patient’s heart rate. This is a quantum leap in CTA of the coronary vessels, where, until now, conventional technology has required considerably higher dose rates. Examinations in the sub-mSv range were only possible in very few, selected patients. Dual Source CT allows scanning every patient with high or irregular heart rates – even without the use of beta blockers to slow down the heart rate. That means, even patients who cannot tolerate beta blockers may be spared referral to invasive angiography.

Reducing contrast agent: Cardiologists prefer Somatom Definition Flash

Somatom Definition Flash’s low-dose scanning potential also benefits patients with heart valve disease who were selected for a TAVI (Transcatheter Aortic Valve Implantation) and must be examined by CT in order to plan the procedure. The minimally invasive TAVI treatment is particularly appropriate for older patients with a high perioperative risk during heart surgery. It links the implantation of an artificial heart valve with a balloon dilatation in the catheter laboratory. The great advantage is that the patient’s thorax must not be opened as the new valve is inserted through the femoral artery or through a small incision between the ribs. For the preparation of this procedure, Somatom Definition Flash brings even more benefits to the user: TAVI patients are usually multimorbid and suffer from renal insufficiency. They can barely metabolize larger quantities of contrast agent that often have to be applied for a CTA to display the coronary arteries and the aorta. “For us, Somatom Definition Flash is the best solution to plan a TAVI because it allows us to reduce contrast agent significantly,” said Tobias Pflederer, MD, cardiologist at University Hospital Erlangen, Germany. “Single-source CTs, for example, require 100 or even 150 milliliters of contrast agent for assessing the abdominal aorta. With the Definition Flash, we need only 40 milliliters for the aorta and the coronary arteries.” The cardiologists in Erlangen only need two seconds to assess the whole aorta including the coronary arteries in one scan. “Using the resulting information, we can plan every single step of the TAVI procedure,” said Pflederer.

TAVI interventions: Syngo.via supports planning for cardiac specialist

Prior to the TAVI treatment, the cardiologists need to clarify many anatomical issues regarding the vessels. They must know, for example, whether there are stenoses in the peripheral arteries. In that case, they could not insert the new valve through the femoral artery. Furthermore, they must determine the diameter of the aortic bulbus (initial part of the aorta) to select the right size of the artificial valve. The imaging software Syngo.via combines the application modules Syngo.CT Vascular Analysis and Syngo.CT Cardiac Function to display a dedicated TAVI planning workflow that helps physicians answer all these questions quickly, easily, and securely. The software, for instance, automatically exposes the aorta and its valves virtually. It reconstructs the vessel in the most important planes and automatically indicates the measurements that the physician has to conduct for his diagnosis. “With Syngo.via, we are also able to predict the angulations that we will need for invasive fluoroscopy in the TAVI procedure, and we can load and adjust them right in the cath lab,” explained Pflederer. “Our first experiences are that this way, the workflow inside the cath lab can be accelerated by 30 percent.” The University Hospital Erlangen conducts three to four TAVI interventions per week. Pflederer believes that the quantity will increase and that TAVI then may also be used for non-high-risk patients. He assumes that soon, other valve diseases may be treated by transcatheter approaches as well.

The products mentioned here are not commercially available in all countries. Due to regulatory reasons the future availability in any country cannot be guaranteed. Further details are available from the local Siemens organizations.

The outcomes achieved by the Siemens customers described herein were achieved in the customer's unique setting.

Since there is no “typical” hospital and many variables exist (e.g., hospital size, case mix, level of IT adoption) there can be no guarantee that others will achieve the same results.

The University Hospital Erlangen and the German Heart Center Munich have a cooperation contract with Siemens Healthcare.

The Siemens Healthcare Sector is one of the world's largest suppliers to the healthcare industry and a trendsetter in medical imaging, laboratory diagnostics, medical information technology and hearing aids. Siemens offers its customers products and solutions for the entire range of patient care from a single source – from prevention and early detection to diagnosis, and on to treatment and aftercare. By optimizing clinical workflows for the most common diseases, Siemens also makes healthcare faster, better and more cost-effective. Siemens Healthcare employs some 48,000 employees worldwide and operates around the world. In fiscal year 2009 (to September 30), the Sector posted revenue of 11.9 billion euros and profit of around 1.5 billion euros.