Variability in quantitative measurement of the same segment with two different intravascular ultrasound systems: in vivo and in vitro studies.

We evaluated two different intravascular ultrasound (IVUS) systems, Atlantis and Intrafocus, to verify their accuracy and reproducibility. In an in vivo study on 20 consecutive patients with coronary artery diseases, the minimum lumen diameter (MLD), vessel diameter, lumen area (LA), vessel area, plaque area, and area stenosis rate (% AS) were respectively measured. In an in vitro study, MLD and LA were measured in four metal tubes with different diameters.