Usefulness of cardiovascular magnetic resonance imaging of the superficial femoral artery for screening patients with diabetes mellitus for atherosclerosis.

Cardiovascular magnetic resonance (CMR) of the superficial femoral artery (SFA) allows direct and noninvasive visualization of atherosclerotic plaque burden. We examined atherosclerosis in 3 groups of patients without history or symptoms of peripheral arterial disease with varying expected burdens: those with diabetes mellitus (DM) and known coronary artery disease (CAD) (n = 24), those with DM and a high prevalence of CAD risk factors (n = 20), and controls of similar age without DM or CAD and few CAD risk factors (n = 15). We also assessed the diagnostic accuracy of this technique to differentiate among these 3 groups. T1-weighted spin-echocardiographic images were used to measure mean wall thickness (WT) and total wall volume indexed to total vessel volume. Diagnostic accuracy was assessed by area under receiver operating characteristics curve analysis. Patients with DM plus risk factors and DM plus CAD had higher mean WT (1.28 and 1.37 mm) and mean indexed wall volume (0.53 and 0.56) compared to controls (mean WT 1.16 mm and mean indexed wall volume 0.45; p <0.010 for all comparisons). Mean WT and indexed wall volume showed good diagnostic accuracy in discriminating controls from those with DM plus CAD (areas under curve 0.85 and 0.87, respectively, p <0.001), whereas only indexed wall volume discriminated DM plus risk factors from controls (area under curve 0.82, p <0.001). Neither could discriminate between DM plus risk factors and DM plus CAD. In conclusion, patients with DM plus risk factors and DM plus CAD had significantly greater atherosclerotic burden in the SFA on CMR imaging than controls of similar age, with good diagnostic accuracy in differentiating these groups. The high reproducibility and reliability of CMR of the SFA may facilitate improved assessment of atherosclerosis prevalence and progression/regression in studies of novel therapies.