Intravascular Ultrasound: Value of Electronic and Mechanical Devices for Quantifying Mild to Moderate Atherosclerosis

To define the accuracy of electronic and mechanical ultrasound (US) devices for deter mining the thickness of intima and media, 32 fresh normal and atherosclerotic human femoral arteries were obtained at necropsy. The samples were imaged with a 64- element array and a mechanically rotating US transducer at 20 MHz. The mean thickness of the intimal and medial layer was measured with electronic calipers followed by histopathologic and micromorphometric analysis. Morphometric correla tion for intima showed r = 0.64 for the electronic and r = 0.58 for the mechanical US device. The correlation between ultrasonic and histologic measurement of medial thickness in normal and diseased specimens was r = 0.79 for the multielement and r = 0.76 for the mechanical transducer. In conclusion, multielement array transducers are equivalent to mechanically driven probes in the quantitative assessment of periph eral arterial wall layers. Both systems lack sufficient accuracy in the determination of mild to moderate intimal thickening.