1000–33 On-line Automated Lumen Volume Measurement With 3-D Intracoronary Ultrasound During Coronary Interventions

The aim of the study was the clinical validation of an on-line fully automated lumen detection technique with intravascular ultrasound (IVUS). Methods Assessment of lumen dimensions with IVUS was performed in 10 pts undergoing transcatheter therapy (5 PTCA, 2 DCA, 3 Stents). The images of 10 coronary segments 20mm long in the treated area were acquired during motorized pull-back (1mm/s) and processed using an automated contour detection algorithm based on acoustic quantification of blood backscatter and coronary wall. For each segment, 171 ultrasound images (8.5/mm) were processed in the laboratory, immediately after acquisition (processing time: 1.35 min.) and subsequently corrected off-line by an experienced analyst. Segment lumen volume was calculated by multiplying mean lumen area by segment length. Results Of the 1,710 on-line IVUS cross-sections obtained, 232 (13.6%) could not be analyzed due to failure of the algorithm used for lumen detection induced by presence of side branches, lack of sharpness of the lumen-wall interface or shadowing from calcium interpreted as lumen. On the remaining frames (1,478; 86.4%), on-line vs off-line comparison for mean lumen area and segment volume was performed. On-line measurement of lumen area and volume were highly correlated with the off-line measurements (r=0.85 for area; see fig. for lumen), with a mean difference of 7.4±14.1% and 5.9±5.4% for lumen area and volume, respectively. Conclusion In selected optimal sequences of images acquired during coronary interventions, on-line automated quantitative 3-D provides reliable measurements of lumen dimension, requiring limited manual interaction.