Ultrasmall superparamagnetic particles of iron oxide in patients with acute myocardial infarction: early clinical experience

Alam, S. R. et al. (2012) Ultrasmall superparamagnetic particles of iron oxide in patients with acute myocardial infarction: early clinical experience. Circulation: Cardiovascular Imaging, 5(5), pp. 559-565. (doi: 10.1161/CIRCIMAGING.112.974907) (PMID:22875883)

Abstract

Background: Inflammation following acute myocardial infarction (MI) has detrimental effects on reperfusion, myocardial remodelling, and ventricular function. Magnetic resonance imaging using ultrasmall superparamagnetic particles of iron oxide can detect cellular inflammation in tissues, and we therefore explored their role in acute MI in humans. Methods and Results: Sixteen patients with acute ST-segment elevation MI were recruited to undergo 3 sequential magnetic resonance scans within 5 days of admission at baseline, 24 and 48 hours following no infusion (controls; n=6) or intravenous infusion of ultrasmall superparamagnetic particles of iron oxide (n=10; 4 mg/kg). T2*-weighted multigradient-echo sequences were acquired and R2* values were calculated for specific regions of interest. In the control group, R2* values remained constant in all tissues across all scans with excellent repeatability (bias of −0.208 s−1, coefficient of repeatability of 26.96 s−1; intraclass coefficient 0.989). Consistent with uptake by the reticuloendothelial system, R2* value increased in the liver (84±49.5 to 319±70.0 s−1; P<0.001) but was unchanged in skeletal muscle (54±8.4 to 67.0±9.5 s−1; P>0.05) 24 hours after administration of ultrasmall superparamagnetic particles of iron oxide. In the myocardial infarct, R2* value increased from 41.0±12.0 s−1 (baseline) to 155±45.0 s−1 (P<0.001) and 124±35.0 s−1 (P<0.05) at 24 and 48 hours, respectively. A similar but lower magnitude response was seen in the remote myocardium, where it increased from 39±3.2 s−1 (baseline) to 80±14.9 s−1 (P<0.001) and 67.0±15.7 s−1 (P<0.05) at 24 and 48 hours, respectively. Conclusions: Following acute MI, uptake of ultrasmall superparamagnetic particles of iron oxide occurs with the infarcted and remote myocardium. This technique holds major promise as a potential method for assessing cellular myocardial inflammation and left ventricular remodelling, which may have a range of applications in patients with MI and other inflammatory cardiac conditions.

• Item Type: Articles
• Additional Information: Sources of funding: This work and Drs Alam, Semple, Fox, and Newby were supported by the British Heart Foundation (SS/CH/09/002, Centre of Research Excellence Award, CH/09/002). The Wellcome Trust Clinical Research Facility and the Clinical Research Imaging Centre were supported by National Heath Service (NHS) Research Scotland through NHS Lothian. This work was supported by a research agreement with Siemens (Siemens Medical, Germany).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Newby, Professor David and Lang, Professor Ninian
• Authors: Alam, S. R., Shah, A. S.V., Richards, J., Lang, N. N., Barnes, G., Joshi, N., MacGillivray, T., McKillop, G., Mirasadraee, S., Payne, J., Fox, K. A.A., Henriksen, P., Newby, D. E., and Semple, S. I.K.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Circulation: Cardiovascular Imaging
• Publisher: American Heart Association
• ISSN: 1941-9651
• ISSN (Online): 1942-0080
• Published Online: 08 August 2012