High frequency ultrasound morphometry of the thoracic aorta. (A) Intact aorta from a DKO mouse in situ demonstrating severe lipid-rich atherosclerotic lesions in the proximal aorta and arch vessels. Surrounding anatomic structures were masked. Ultrasound images (40 MHz) of the aorta in its long-axis from the aortic valve level to the mid arch from are shown for a wild-type (B), and DKO (C) mouse. In the DKO mouse, there is discrete plaque formation in the proximal brachiocephalic artery (black arrow) and severe thickening of the lesser curvature (white arrows) between the aortic lumen and right pulmonary artery. (D) Mean (±SEM) vessel wall thickness measured at the lesser curvature of the aorta and the brachiocephlic artery. N=10,10,7 for wild-type mice at 10, 20, 40 wks of age, respectively. N=13, 11, 12 for DKO mice at 10, 20, 40 wks of age, respectively. *p<0.01 vs wild type.