Retrospective image-based gating of intracoronary ultrasound images for improved quantitative analysis: the intelligate method.

Quantitative analysis of intracoronary ultrasound (ICUS) studies is performed on a series of tomographic cross-sectional ICUS images acquired during a motorized 0.5 mm/sec catheter pullback. Catheter displacement in the vascular lumen during the cardiac cycle causes an anatomically shuffled ICUS study, which results in a sawtooth-shaped appearance of the coronary segment in longitudinal reconstructed views in quantitative coronary ultrasound software packages. This hampers contour detection and leads to a laborious time-consuming semiquantitative analysis process that may produce inaccurate results. To solve these problems, in the past, online ECG-gated acquisition hardware has been applied. This article describes a novel image-based gating method called Intelligate, which features automatic retrospective selection of end-diastolic frames from videotaped or digitally stored ICUS studies. Our evaluation shows that there are no quantitative differences between analysis results of hardware ECG-gated and Intelligated ICUS studies.