Bruining et al. should be congratulated on their informative paper demonstrating that electrocardiogram (ECG) gating improves volumetric measurements from three-dimensional intracoronary ultrasound images . The ECG gating not only smooths the longitudinal image and makes it visually more pleasing, it also improves the quantitative analysis. The volumes of the artery lumen and the vessel (i.e., the area bounded by the media) were larger when measured by a nongated computer edge-detection program as compared with the ECG-gated program. The major downside to this method is that the image acquisition rate is slow at 1 min/cm of artery. This rate may be feasible for dedicated IVUS researchers, but the casual user of intravascular ultrasound may find this too laborious. However, the longitudinal images more closely approximates an angiographic view and therefore is a more familiar presentation for the interventional cardiologist. As the authors have pointed out, the ECG-gating technique may be more appropriate for serial studies that attempt to look at the volume of atherosclerotic plaque over time.
This article reminds us that, in addition to ECG gating, there are new developments in the field of intravascular ultrasound imaging. Perhaps the most significant advance is complete digital storage of all the cross-sectional ultrasound images. With this new capability, the operator will be able to scroll through the database of images to review all cross-sectional information and the long-axis reconstructed projections. The ability to recall the images from a digital