Recently, ultrasound tissue characterization of the carotid arteries with an integrated backscatter (IB) analysis was shown to identify a high-risk group of atherosclerosis. To clarify whether IB ultrasound is useful in assessing arterial sclerosis as well as stiffness beta and whether IB values reflect the histological structure, we measured IB values of common carotid media in 52 subjects without coronary risk factors and in 10 patients with systemic sclerosis (SSc) in the clinical studies and 12 patients in the histological studies with a Philips Medical Systems Sonos 5500. IB values were correlated with age (r=0.69, P<0.0001), intima-media thickness (r=0.72, P<0.0001) and stiffness beta (r=0.80, P<0.0001) in the control subjects. IB values and stiffness beta in the SSc group were greater than in an age- and sex-matched control group (IB values: 9.6+/-2.7dB versus 16.1+/-1.8dB; stiffness beta: 11.5+/-4.5 versus 20.6+/-5.6, P<0.01). IB values of the media were correlated with the elastic fragmentation index (r=0.63, P=0.029) and the collagen fiber index (r=0.59, P=0.046). Measurements of IB values of carotid media are useful for non-invasively evaluating arterial sclerosis.