At the University Medical Center Mannheim, Germany, radiologists and cardiologists are jointly developing an algorithm for an individualized – that is, adapted to the patient’s risk factor – yet standardized, diagnostic path for patients with suspected coronary artery disease (CAD). They particularly use the diagnostic quality of coronary computed tomography angiography (CTA) and magnetic resonance imaging (MRI). Professor Stefan Schönberg, MD, Director of the Institute for Clinical Radiology and Nuclear Medicine, explains, ”We are looking at the definition and implementation of the entire process, from diagnosis to treatment and follow-up. When coronary heart disease is suspected, the cardiologist first determines the risk of its presence. We then hold joint discussion about the diagnostic approach, arrive at the diagnosis, and the cardiologists make the necessary interventions, if required. To this end, we require an excellent workflow since every second counts when suspecting coronary artery disease in an acute setting.” At the institute, this excellent workflow is supported by two high-end Siemens systems: the Dual Source CT scanner SOMATOM® Definition and the MR System MAGNETOM® Avanto. In 2008, the institute also put a 3 Tesla MAGNETOM Trio – a Tim® (Total imaging matrix) System into operation.

“Today, contrast-enhanced CTA can be used for excluding relevant stenoses, and cardiovascular MRI can be used for evaluating morphology, tissue characterization, and cardiac function,“ says Tim Süselbeck, MD, Head of the Cath Lab. Particularly for patients with medium risk, CTA can rule out relevant stenoses. According to Christian Fink, MD, Section Chief of Cardiothoracic Imaging, the high negative predictive value is the greatest benefit of the method: “If the images are diagnostic, coronary stenoses can be ruled out at more than 95 percent probability.” Additionally, CTA provides important information about the calcium score, which is an independent risk factor for a subsequent coronary event.

In those patients, if stenoses in major coronary arteries can be excluded with a high level of confidence after CTA and if additional examinations are indicated, for example, or when the hemodynamic relevance of detected stenoses is to be determined, advanced diagnostic imaging techniques are applied. Besides myocardial scintigraphy and stress echocardiography, mainly stress MRI is considered. Stress MRI provides proof by visualization of wall motion abnormalities or by tissue characterization. As Schönberg points out, “Stress MRI shows a better spatial resolution than myocardial scintigraphy and works without radiation exposure. The 3 Tesla magnet of MAGNETOM Trio further improves spatial resolution, contrast, and speed of acquisition. Parallel acquisition techniques will allow high-resolution functional analyses of the entire heart within a few breath-holds. These represent undeniable advantages for both workflow and patient.”