Although selective contrast coronary arteriography has been the gold standard approach for coronary imaging since more than 30 years, new coronary imaging techniques are currently under development. Intravascular ultrasound (IVUS) is perhaps the most promising of these additional techniques. IVUS makes use of miniaturised crystals incorporated at catheter tips and provides real time, cross-sectional and longitudinal, high resolution images of the arterial wall with three-dimensional reconstruction capabilities (Pandian, 1989; Coy et al., 1991; Liebsen & Klein, 1992). Different devices have been constructed. Actually two types are being used: mechanical (hand-rotated or motor-driven) systems and phased array systems using high-frequency (20-30 MHz) transducers (Bom et al., 1989). Coronary ultrasound imaging performed during catheterization is feasible and safe as demonstrated in several studies examining normal and pathologic coronary arteries (De Scheerder et al., in press).