We used ultrasonography to evaluate atherosclerotic lesions in the common carotid arteries of 169 outpatients and inpatients (92 male, 77 female; mean age, 58.2 years), to determine the relation with various
risk factors for atherosclerosis as well as the utility of ultrasonography in the quantitative evaluation of
atherosclerotic diseases. A 7.5 MHz transducer was used to evaluate atherosclerotic lesions on the basis of
the thickness of their intimal-medial complex, which we term wall thickness, and the presence of mural
plaque; the relation between these measurements and age, sex, blood pressure, smoking history (n=68),
diabetes mellitus (n=25), lipid metabolism, and atherosclerotic diseases (n=19) was also studied. Wall thickness of the common carotid arteries and age (male group: r=0.750; female group: r=0.548), Brinkman index, (r=0.284), systolic pressure (r=0.504), and diastolic pressure (r=0.204) correlated positively. Wall thickness was significantly greater and plaques were present significantly more frequently present in patients
with a history of smoking and diabetes mellitus. There was no correlation with lipid metabolism, however.
Multiple regression analysis using these risk factors as explanatory variables showed that age, Brinkman
index, systolic pressure, and diabetes mellitus contributed significantly to increased wall thickness. Wall
thickness was significantly greater in patients with atherosclerotic diseases such as cerebral infarction and
ischemic heart diseases; 69% of those with a wall thickness 0.9 mm or greater had atherosclerosis. These
findings indicate that blood pressure and age contribute to risk of formation of atherosclerotic lesions in the
common carotid artery, and that smoking and diabetes mellitus are important risk factors, as well. Ultrasonographically measured wall thickness was clinically useful for detecting the presence of such atherosclerotic diseases as cerebral infarction and ischemic heart diseases.