ECG-gated versus nongated three-dimensional intracoronary ultrasound analysis: Implications for volumetric measurements

The quantitative analysis of a three-dimensional (3-D) intracoronary ultrasound (ICUS) image data set permits a more comprehensive assessment of coronary arterial segments. The 3-D image sets are generally acquired during continuous motorized pullbacks. However, the cyclic changes of vascular dimensions and the cyclic spatial displacement of the ICUS transducer relative to the vessel wall can result in characteristic image artifacts, which may limit the applicability of quantitative automated analysis systems. This limitation may be overcome by an ECG-gated image acquisition. In the present study we acquired in vivo (1) nongated and (2) ECG-gated 3-D ICUS image sets of 15 human atherosclerotic coronary arteries and performed a computer-assisted contour detection of the lumen and total vessel boundaries. Total vessel and lumen volumes measured significantly larger in the nongated versus ECG-gated end-diastolic image sets (753 ± 307 mm³ vs. 705 ± 305 mm³ 411 ± 154 mm³ vs. 388 ± 165 mm³, both: P < 0.05). Both end-diastolic and systolic measurements were available in nine arteries, showing a larger total vessel and lumen volume at systole (664 ± 221 mm³ vs. 686 ± 227 mm³, P = 0.03; 384 ± 164 mm³ vs. 393 ± 170 mm³, P = 0.08). The differences observed may be of particular interest for volumetric ICUS studies, addressing presumably small differences in vessel or lumen dimensions.