Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-13492 Wissenschaftlicher Artikel Reiter, Theresa; Gensler, Daniel; Ritter, Oliver; Weiss, Ingo; Geistert, Wolfgang; Kaufmann, Ralf; Hoffmeister, Sabine; Friedrich, Michael T.; Wintzheimer, Stefan; Düring, Markus; Nordbeck, Peter; Jakob, Peter M.; Ladd, Mark E.; Quick, Harald H.; Bauer, Wolfgang R. Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures Background: One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating. Methods: A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip. Results: A maximum temperature rise of 22.4 degrees C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2 degrees C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8 degrees C. Conclusion: Up to a maximum of 22.4 degrees C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip system can be used to increase MR safety of EP catheters by suppressing the effects of unwanted passive catheter heating due to RF exposure from the MR scanner. 2012 Journal of Cardiovascular Magnetic Resonance 14 12 urn:nbn:de:bvb:20-opus-134927 10.1186/1532-429X-14-12 Physikalisches Institut OPUS4-6459 Wissenschaftlicher Artikel Reiter, Theresa; Ritter, Oliver; Prince, Martin R.; Nordbeck, Peter; Wanner, Christoph; Nagel, Eike; Bauer, Wolfgang R. Minimizing Risk of Nephrogenic systemic fibrosis in Cardiovascular Magnetic Resonance Nephrogenic Systemic Fibrosis is a rare condition appearing only in patients with severe renal impairment or failure and presents with dermal lesions and involvement of internal organs. Although many cases are mild, an estimated 5 % have a progressive debilitating course. To date, there is no known effective treatment thus stressing the necessity of ample prevention measures. An association with the use of Gadolinium based contrast agents (GBCA) makes Nephrogenic Systemic Fibrosis a potential side effect of contrast enhanced magnetic resonance imaging and offers the opportunity for prevention by limiting use of gadolinium based contrast agents in renal failure patients. In itself toxic, Gadolinium is embedded into chelates that allow its safe use as a contrast agent. One NSF theory is that Gadolinium chelates distribute into the extracellular fluid compartment and set Gadolinium ions free, depending on multiple factors among which the duration of chelates exposure is directly related to the renal function. Major medical societies both in Europe and in North America have developed guidelines for the usage of GBCA. Since the establishment of these guidelines and the increased general awareness of this condition, the occurrence of NSF has been nearly eliminated. Giving an overview over the current knowledge of NSF pathobiochemistry, pathogenesis and treatment options this review focuses on the guidelines of the European Medicines Agency, the European Society of Urogenital Radiology, the FDA and the American College of Radiology from 2008 up to 2011 and the transfer of this knowledge into every day practice. 2012 urn:nbn:de:bvb:20-opus-75068 Medizinische Klinik und Poliklinik I OPUS4-12316 Wissenschaftlicher Artikel Reiter, Theresa; Ritter, Oliver; Nordbeck, Peter; Beer, Meinrad; Bauer, Wolfgang Rudolf MRI-guided ablation of wide complex tachycardia in a univentricular heart Magnetic resonance imaging can be used for preprocedural assessment of complex anatomy for radiofrequency (RF) ablations, e.g., in a univentricular heart. This case report features the treatment of a young patient with a functionally univentricular heart who suffered from persistent sudden onset tachycardia with wide complexes that required RF ablation as treatment. 2012 260-263 World Journal of Cardiology 4 8 urn:nbn:de:bvb:20-opus-123165 10.4330/wjc.v4.i8.260 Medizinische Klinik und Poliklinik I OPUS4-12563 Wissenschaftlicher Artikel Nordbeck, Peter; Beer, Meinrad; Köstler, Herbert; Ladd, Mark E.; Quick, Harald H.; Bauer, Wolfgang R.; Ritter, Oliver Cardiac catheter ablation under real-time magnetic resonance guidance One of the main shortcomings of interventional electrophysiology (EP) is its inability to generate sufficient soft tissue contrast for intra-procedural visualization of the myocardium and the surrounding tissue, using conventional imaging techniques. Interventional cardiovascular magnetic resonance imaging (MRI) aims at bringing about significant improvements to the complex and decisive EP interventions far beyond the capabilities of currently available supportive imaging techniques used to surmount the drawbacks of fluoroscopy, as MRI not only allows of precise three-dimensional exposure of the cardiovascular morphology, but also proves to be a promising technique exclusively suitable for direct visualization of arrhythmogenic substrate and therapeutic effects. The major challenge posed by clinical … 2012 European Heart Journal 33 15 urn:nbn:de:bvb:20-opus-125638 10.1093/eurheartj/ehs139 Institut für diagnostische und interventionelle Radiologie (Institut für Röntgendiagnostik)