Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts

Abstract

We sought to elucidate the mechanisms underlying two common intravascular optical coherence tomography (IV-OCT) artifacts that occur when imaging metallic stents: “merry-go-rounding” (MGR), which is an increase in strut arc length (SAL), and “blooming,” which is an increase in the strut reflection thickness (blooming thickness). Due to uncontrollable variables that occur in vivo, we performed an in vitro assessment of MGR and blooming in stented vessel phantoms. Using Xience V and Driver stents, we examined the effects of catheter offset, intimal strut coverage, and residual blood on SAL and blooming thickness in IV-OCT images. Catheter offset and strut coverage both caused minor MGR, while the greatest MGR effect resulted from light scattering by residual blood in the vessel lumen, with 1% hematocrit (Hct) causing a more than fourfold increase in SAL compared with saline (p<0.001 ). Residual blood also resulted in blooming, with blooming thickness more than doubling when imaged in 0.5% Hct compared with saline (p<0.001 ). We demonstrate that a previously undescribed mechanism, light scattering by residual blood in the imaging field, is the predominant cause of MGR. Light scattering also results in blooming, and a newly described artifact, three-dimensional-MGR, which results in “ghost struts” in B-scans.

Highly NIR-II Scattering Gold Superclusters for Intravascular Optical Coherence Tomography Molecular Imaging

“…In routine stent evaluation by IV-OCT, common radial artifacts due to the stent arise, known as bloom (the result of laser backscattering) and merry-go-round (the result of laser attenuation or shadowing). 58,59 The binding of AuSC@(13FS)2 to endovascular P-selectin would result in the accumulation of metal at the endovascular surface and the generation of both bloom and merry-go-round image features, which we termed as Reflection or scattering events (ROSEs) (Fig. 6A).…”