Coronary artery lumen volume measurement using three-dimensional intravascular ultrasound: validation of a new technique.

OBJECTIVE

To validate an automated algorithm for the measurement of lumen volumes of coronary arteries.

BACKGROUND

Current intravascular ultrasound systems use absolute measurements of and changes in areas and diameters for the assessment of coronary artery disease. However, the coronary artery is a three-dimensional structure of complex geometry and volume.

METHODS

We used a comprehensive imaging system designed to reconstruct planar intravascular ultrasound images in three dimensions. This system consisted of a 25 MHz transducer-tipped rigid probe (for in vitro studies) or a 25 MHz transducer-tipped catheter within a 3.9F monorail imaging sheath (for in vivo studies), a motorized catheter pullback device that withdrew the transducer at 0.5 mm/sec, and an image processing computer that stacked 15 image slices/mm of vessel axial length and then performed threshold-based three-dimensional image rendering and lumen volume measurement. We imaged 13 human coronary vessels (6 RCA, 6 LAD, 1 LCX) in vitro and 16 vessels (8 LAD, 6 RCA, 2 SVG) in vivo.

IN VITRO STUDIES

Lumen volumes derived by three-dimensional intravascular ultrasound were 171 +/- 121 mm3 and compared very well with those derived by histology (160 +/- 109 mm3, r = 0.97, SEE = 29 mm3, P < 0.001) and with those derived by manual planimetry of planar intravascular ultrasound images (150 +/- 106 mm3, r = 0.97, SEE = 30 mm3, P < 0.001). In vivo studies: Lumen volumes derived by three-dimensional intravascular ultrasound were 74 +/- 35 mm3 and compared well with those derived by quantitative angiography (52 +/- 20 mm3, r = 0.71, SEE = 25 mm3, P < 0.002).

CONCLUSIONS

Three-dimensional intravascular ultrasound is a new technique that can accurately measure coronary artery lumen volumes. Further technical improvements may help to establish this technique as the new standard for lumen volume measurement.