Articles from Circulation

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Bluemke, David A. ; Achenbach, Stephan ; Budoff, Matthew et al
Noninvasive Coronary Artery Imaging: Magnetic Resonance Angiography and Multidetector Computed Tomography Angiography: A Scientific Statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young.
Circulation. Status Publish Ahead of Print, published online before print, 27 June 2008

Gavazzi, Emanuele; Ravanelli, Marco; Farina, Davide; Chiari, Maria Elena; Maroldi, Roberto
Scimitar Syndrome: Comprehensive, Noninvasive Assessment With Cardiovascular Magnetic Resonance Imaging
Source
Circulation. 118(3):e63-e64, July 15, 2008.

von zur Muhlen, C ; von Elverfeldt, D ; Moeller, J A. ; Choudhury, R P. et al
Magnetic Resonance Imaging Contrast Agent Targeted Toward Activated Platelets Allows In Vivo Detection of Thrombosis and Monitoring of Thrombolysis
Circulation. 118(3):258-267, July 15, 2008.
Abstract
Background-: Platelets are the key to thrombus formation and play a role in the development of atherosclerosis. Noninvasive imaging of activated platelets would be of great clinical interest. Here, we evaluate the ability of a magnetic resonance imaging (MRI) contrast agent consisting of microparticles of iron oxide (MPIOs) and a single-chain antibody targeting ligand-induced binding sites (LIBS) on activated glycoprotein IIb/IIIa to image carotid artery thrombi and atherosclerotic plaques.Methods and Results-: Anti-LIBS antibody or control antibody was conjugated to 1-[mu]m MPIOs (LIBS MPIO/control MPIO). Nonocclusive mural thrombi were induced in mice with 6% ferric chloride. MRI (at 9.4 T) was performed once before and repeatedly in 12-minute-long sequences after LIBS MPIO/control MPIO injection. After 36 minutes, a significant signal void, corresponding to MPIO accumulation, was observed with LIBS MPIOs but not control MPIOs (P<0.05).>

Nazarian, Saman ; Kolandaivelu, Aravindan ; Zviman, Menekhem M. et al
Feasibility of Real-Time Magnetic Resonance Imaging for Catheter Guidance in Electrophysiology Studies
Circulation. 118(3):223-229, July 15, 2008.
Abstract
Background-: Compared with fluoroscopy, the current imaging standard of care for guidance of electrophysiology procedures, magnetic resonance imaging (MRI) provides improved soft-tissue resolution and eliminates radiation exposure. However, because of inherent magnetic forces and electromagnetic interference, the MRI environment poses challenges for electrophysiology procedures. In this study, we sought to test the feasibility of performing electrophysiology studies with real-time MRI guidance.Methods and Results-: An MRI-compatible electrophysiology system was developed. Catheters were targeted to the right atrium, His bundle, and right ventricle of 10 mongrel dogs (23 to 32 kg) via a 1.5-T MRI system using rapidly acquired fast gradient-echo images ([almost equal to]5 frames per second). Catheters were successfully positioned at the right atrial, His bundle, and right ventricular target sites of all animals. Comprehensive electrophysiology studies with recording of intracardiac electrograms and atrial and ventricular pacing were performed. Postprocedural pathological evaluation revealed no evidence of thermal injury to the myocardium. After proof of safety in animal studies, limited real-time MRI-guided catheter mapping studies were performed in 2 patients. Adequate target catheter localization was confirmed via recording of intracardiac electrograms in both patients.Conclusions-: To the best of our knowledge, this is the first study to report the feasibility of real-time MRI-guided electrophysiology procedures. This technique may eliminate patient and staff radiation exposure and improve real-time soft tissue resolution for procedural guidance.

Flogel, Ulrich PhD; Ding, Zhaoping MD; Hardung, Hendrik et al
In Vivo Monitoring of Inflammation After Cardiac and Cerebral Ischemia by Fluorine Magnetic Resonance Imaging.
Circulation. 118(2):140-148, July 8, 2008.
Abstract Background-: In this study, we developed and validated a new approach for in vivo visualization of inflammatory processes by magnetic resonance imaging using biochemically inert nanoemulsions of perfluorocarbons (PFCs).Methods and Results-: Local inflammation was provoked in 2 separate murine models of acute cardiac and cerebral ischemia, followed by intravenous injection of PFCs. Simultaneous acquisition of morphologically matching proton (1H) and fluorine (19F) images enabled an exact anatomic localization of PFCs after application. Repetitive 1H/19F magnetic resonance imaging at 9.4 T revealed a time-dependent infiltration of injected PFCs into the border zone of infarcted areas in both injury models, and histology demonstrated a colocalization of PFCs with cells of the monocyte/macrophage system. We regularly found the accumulation of PFCs in lymph nodes. Using rhodamine-labeled PFCs, we identified circulating monocytes/macrophages as the main cell fraction taking up injected nanoparticles.Conclusions-: PFCs can serve as a "positive" contrast agent for the detection of inflammation by magnetic resonance imaging, permitting a spatial resolution close to the anatomic 1H image and an excellent degree of specificity resulting from the lack of any 19F background. Because PFCs are nontoxic, this approach may have a broad application in the imaging and diagnosis of numerous inflammatory disease states. Schwitter, Juerg Extending the Frontiers of Cardiac Magnetic Resonance. [editorial] Circulation. 118(2):109-112, July 8, 2008.Flogel, Ulrich PhD; Ding, Zhaoping MD; Hardung, Hendrik et al In Vivo Monitoring of Inflammation After Cardiac and Cerebral Ischemia by Fluorine Magnetic Resonance Imaging. Circulation. 118(2):140-148, July 8, 2008. Abstract Background-: In this study, we developed and validated a new approach for in vivo visualization of inflammatory processes by magnetic resonance imaging using biochemically inert nanoemulsions of perfluorocarbons (PFCs).Methods and Results-: Local inflammation was provoked in 2 separate murine models of acute cardiac and cerebral ischemia, followed by intravenous injection of PFCs. Simultaneous acquisition of morphologically matching proton (1H) and fluorine (19F) images enabled an exact anatomic localization of PFCs after application. Repetitive 1H/19F magnetic resonance imaging at 9.4 T revealed a time-dependent infiltration of injected PFCs into the border zone of infarcted areas in both injury models, and histology demonstrated a colocalization of PFCs with cells of the monocyte/macrophage system. We regularly found the accumulation of PFCs in lymph nodes. Using rhodamine-labeled PFCs, we identified circulating monocytes/macrophages as the main cell fraction taking up injected nanoparticles.Conclusions-: PFCs can serve as a "positive" contrast agent for the detection of inflammation by magnetic resonance imaging, permitting a spatial resolution close to the anatomic 1H image and an excellent degree of specificity resulting from the lack of any 19F background. Because PFCs are nontoxic, this approach may have a broad application in the imaging and diagnosis of numerous inflammatory disease states.

Schwitter, Juerg Extending the Frontiers of Cardiac Magnetic Resonance. [editorial]
Circulation. 118(2):109-112, July 8, 2008.