Accuracy of Stent Measurements Using ECG-Gated Greyscale Intravascular Ultrasound Images: A Validation Study

Greyscale intravascular ultrasound (IVUS) is an accurate tool for measuring stent dimensions and residual disease at the stent edge. Electrocardiographically (ECG)-gated IVUS is used in evolving second-generation IVUS systems, but this modality provides fewer greyscale cross-sectional images, and its accuracy to measure stent dimensions has not been assessed. This study was designed to validate the use of ECG-gated greyscale IVUS in measuring minimum stent area (MSA), stent length and reference dimensions compared to standard greyscale IVUS data. IVUS imaging was performed after drug-eluting stent implantation in 53 target lesions in 48 patients with acute coronary syndrome. The IVUS catheter was mechanically withdrawn at 0.5 mm/s, standard greyscale images were collected at 10 frames/s, and ECG-gated greyscale images were constructed from R-wave gated images. The MSA measured 6.20 ± 1.75 mm2 vs. 5.98 ± 1.55 mm2 on standard greyscale and ECG-gated greyscale IVUS, respectively (R2 = 0.91, p = 0.005). The MSA position (R2 = 0.66, p = 0.179) and stent length (R2 = 0.99, p = 0.435) measurements were similar between modalities. Proximal reference vessel area was larger by ECG-gated IVUS, but proximal reference lumen and distal reference measurements were similar. Bland-Altman plots demonstrated good agreement between modalities. In conclusion, ECG-gated greyscale IVUS provides accurate and reliable measurements of stent length, area and reference segment plaque burden after stent implantation and is not inferior to standard greyscale IVUS. (E-mail: gsm18439@aol.com or gmintz@crf.org).