Quantitative precision of optical frequency domain imaging: direct comparison with frequency domain optical coherence tomography and intravascular ultrasound.

Yuhei Kobayashi,Peter J. Fitzgerald,Shigemitsu Tanaka,Yasuhiro Honda,Takumi Kimura,Hideki Kitahara,Kozo Okada,Paul G. Yock,Fumiaki Ikeno

doi:10.1007/s12928-015-0349-x

Abstract

No systematic validation study is available with optical frequency domain imaging (OFDI), directly compared with frequency domain optical coherence tomography (FD-OCT) and intravascular ultrasound (IVUS). Controversy also remains about the impact of different stent contour tracing methods by OFDI/FD-OCT. In vitro: coronary phantom models (1.51–5.04 mm) were imaged with OFDI, FD-OCT, and IVUS, demonstrating excellent quantitative precision with a slight overestimation of mean lumen diameter (difference 0.01–0.02 mm). In vivo: corresponding 64 OFDI/IVUS images of stented coronary segments from 20 swines were analyzed. Minimum lumen area by OFDI was larger than IVUS at baseline (P < 0.001), whereas it was smaller than IVUS at follow-up. When stent was traced at leading edges of struts by OFDI, minimum stent area was similar between OFDI and IVUS (P = 0.60). When traced at the highest intensity points of struts by OFDI, it was significantly larger in OFDI than in IVUS (P < 0.001). Three modalities have clinically acceptable precision across the wide range of lumen diameters. In vivo measurements by OFDI and IVUS could slightly be discrepant depending on the parameters and time points. In stent assessment by OFDI, the 2 methods led to a small but systematic difference; therefore, consistency in methodology is advised for comparative studies.

Highlights

Time domain and frequency domain (FD) optical coherence tomographies (OCTs) have been consistently shown to provide more precise lumen measurements compared to conventional 40-megahertz (MHz) intravascular ultrasound (IVUS) both in vitro and in vivo, owing to their much higher resolution and better contrast of lumen border than IVUS systems [1,2,3].Recently, optical frequency domain imaging (OFDI) has become clinically available as another second-generation intravascular optical imaging system
No systematic validation study is available with optical frequency domain imaging (OFDI), directly compared with frequency domain optical coherence tomography (FD-OCT) and intravascular ultrasound (IVUS)
In vivo measurements by OFDI and IVUS could slightly be discrepant depending on the parameters and time points

Summary

Introduction

Time domain and frequency domain (FD) optical coherence tomographies (OCTs) have been consistently shown to provide more precise lumen measurements compared to conventional 40-megahertz (MHz) intravascular ultrasound (IVUS) both in vitro and in vivo, owing to their much higher resolution and better contrast of lumen border than IVUS systems [1,2,3].Recently, optical frequency domain imaging (OFDI) has become clinically available as another second-generation intravascular optical imaging system. While a first-in-human study demonstrated the feasibility and safety of OFDI, [4] there had been no systematic validation study directly comparing OFDI with FD-OCT These secondgeneration OCT systems adopt the same technical principle, there is a theoretical concern that practical differences in image data processing and system configurations may lead to considerable variability in quantitative precision, as previously demonstrated in IVUS systems [5, 6]. It remains controversial whether stent contour should be traced at leading edges or the highest intensity points when assessing with intravascular optical imaging systems [7]. The secondary goal was to compare OFDI stent measurements between tracing at leading edges and the highest intensity points

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