A new finite element method for inverse problems in structural analysis: application to atherosclerotic plaque elasticity reconstruction

摘要

Atherosclerotic plaque rupture remains the leading cause of acute coronary syndrome (ACS), myocardial infarction and stroke (Lloyd-Jones et al. 2010). Atherosclerotic lesions develop inside the arterial wall. Vulnerable plaque (VP), which is characterised by a relatively large extracellular necrotic core and a thin fibrous cap infiltrated by macrophages, is prone to rupture (Virmani et al. 2000). The rupture of the thin-cap fibroatheroma may lead to the formation of a thrombus, causing the acute syndrome and possibly death (Virmani et al. 2006). The disease remains asymptomatic for a long time, but early detection of vulnerable atherosclerotic lesions is a crucial step in preventing risk of rupture and managing ACS and strokes. Accurate quantification of both morphology (Ohayon et al. 2008) and mechanical properties of the diseased arteries (Finet et al. 2004) are critical keys in the detection of VP. Indeed, peak cap stress (PCS) amplitude has been identified as the biomechanical key predictor of vulnerability to rupture (Finet et al. 2004). Quantifying PCS in vivo remains a challenge as it depends not only on the VP morphology, but also on the mechanical properties of the plaque components (Ohayon et al. 2008). Although several methods have been developed to extract the spatial strain distributions (Doyley et al. 2001; Maurice et al. 2004), the complex geometries of atherosclerotic plaques inhibit direct translation into plaque mechanical properties.