Contrast-enhanced B-mode US angiography in the assessment of experimental in vivo and in vitro atherosclerotic disease

Rationale and Objectives. This study was performed to (a) test the hypothes is that filling the arterial lumen with echoes at B-mode ultrasound (US) en ables the assessment of wall and luminal abnormalities and (b) compare cont rast material-enhanced B-mode US with color and power Doppler US angiograph y. Materials and Methods. Atherosclerotic lesions were created in 14 rabbit ao rtas and imaged with color Doppler and B-mode US before and after the intra venous administration of 0.3 mL of AF0150, a US contrast agent. In addition , four replicas of diseased human carotid arteries were immersed in a tissu e-mimicking phantom and imaged with B-mode and color and power Doppler US b efore and after the administration of 1 mL of AF0150 per liter of porcine b lood. Radiopaque plastic casts of the rabbit aortas and contact radiographs of the plastic replicas served as standards. Results, Although color and power Doppler US allowed immediate localization of the lumen, precise estimation of stenoses and reliable visualization of surface irregularities were not possible. After AF0150 administration, ang iogram-like images of the lumen were created with B-mode US, allowing rapid assessment of the entire vessel lumen and wall. Consequently, luminal sten oses were more accurately measured than with unenhanced B-mode US (r(2) = 0 .94, P < .0001 vs r(2) = 0.21, P = .25) or Doppler (r(2) = 0.42, P < .03), In addition, plaques and ulcerations were visible only with contrast-enhanc ed B-mode US. Conclusion. Microbubbles fill the arterial lumen with echoes at B-mode US, creating an angiogram-like image. The ability to visualize the inner and ou ter surfaces of the vascular wall improved the evaluation of luminal and wa ll abnormalities.