Abstract 17328: Ultrasmall Supraparamagnetic Particles of Iron Oxide-enhanced Magnetic Resonance Imaging in the Assessment of Cellular Inflammation after Myocardial Infarction

Abstract

Introduction: Excessive inflammation after myocardial infarction (MI) can be detrimental to the recovery of cardiac function. Ultrasmall superparamagnetic particles of iron oxide (USPIO)-enhanced magnetic resonance imaging (MRI) can detect myocardial cellular inflammation after MI. We aimed to determine the time course and duration of USPIO-enhancement following acute MI. Methods: Twenty-one patients with acute MI were studied in the 3-month period following acute MI. Repeated T2*-weighted 3T MRI was performed throughout and 24 h after USPIO (ferumoxytol, 4 mg/kg) administration at 4±3, 12±2, 21±4 and 90±9 days. Myocardial regions of interest (ROIs) were drawn and categorised into infarct and non-infarct regions by the presence or absence of late gadolinium enhancement (LGE). R2* values within ROIs were determined to assess the time course and duration of uptake and clearance of USPIO. Results: Following single-dose USPIO administration 2-7 days after acute MI, USPIO uptake is demonstrable at 24 h (p<0.0001) and is cleared within 4-8 days (Figure 1a). Increased USPIO uptake is seen in the infarct region at days 2-7 (p<0.0001), and days 10-14 (p<0.05) compared to non-infarcted myocardium (Figure 1b). Conclusions: For the first time, we have shown USPIO-enhanced MRI can detect and quantify infarct-related cellular inflammation in the first 2 weeks following acute MI.