1.1 Current Carotid Risk Assessment In current clinical practice, selection for surgical removal of the carotid plaque (carotid endarterectomy) is determined by the degree of luminal narrowing known as the degree of stenosis (Rothwell et al., 2003a). The operation has been determined beneficial in patients with symptomatic, severe stenosis in two large, randomized trials; the North American Symptomatic Carotis Endarterectomy Trial (NASCET, 1991) and the European Carotid Surgery Trial (ECST, 1998). To determine the degree of stenosis, NASCET and ECST used measurements based on x-ray digital subtraction angiographies. Today, Doppler ultrasound is used in clinical practice for determination of the degree of stenosis (Nederkoorn et al., 2003; Titi et al., 2007). This technique does not rely on direct measurements of the degree of stenosis but uses determination of maximum peak systolic and end diastolic blood flow velocities as well as the spectral composition of these velocities to assess the degree of stenosis. The ultrasound Doppler techniques, though in universal clinical use, are problematic due to problems with the insonation angle affecting the Doppler equation (Tola and Yurdakul, 2006; Claudon et al., 2001), interand intra-observer variations (Mead et al., 2000; Lui et al., 2005), and interpretation in the presence of complex geometries (Clevert et al., 2006; Clevert et al., 2007). Preventive treatment of patients with carotid plaques but no symptoms (asymptomatic patients) would be preferable but is controversial, since trials have shown only marginal effect of treatment from current risk stratification, and total mortality after five years is unchanged in treated vs. untreated groups (Halliday et al., 2004; Redgrave et al., 2006). To prevent a single stroke, the number needed to treat for symptomatic patients is seven (Rothwell et al., 2003a) rising to forty for asymptomatic patients (Halliday et al., 2004). Using the current risk assessment algorithm, the majority of patients operated are thus needlessly exposed to peri-operative risks. Further, atherosclerotic plaques tend to grow outwards initially, which may result in normal luminal size belying substantial plaque volumes, a process known as arterial remodeling (Glagov et al., 1987; Glagov et al., 1988;