Advances in IVUS/OCT and Future Clinical Perspective of Novel Hybrid Catheter System in Coronary Imaging

Abstract

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been developed and improved as both diagnostic and guidance tools for interventional procedures over the past three decades. IVUS has a resolution of 100 μm with a high tissue penetration and capability of assessing the entire structure of a coronary artery including the external elastic membrane, whereas OCT has a higher resolution of 10-20 μm to assess endoluminal structures with a limited tissue penetration compared to IVUS. Recently, two companies, CONAVI and TERUMO, integrated IVUS and OCT into a single catheter system. With their inherent strength and limitations, the combined IVUS and OCT probes are complementary and work synergistically to enable a comprehensive depiction of coronary artery. In this review, we summarize the performance of the two intracoronary imaging modalities-IVUS and OCT-and discuss the expected potential of the novel hybrid IVUS-OCT catheter system in the clinical field.

Keywords: hybrid IVUS–OCT catheter; intracoronary imaging; intravascular ultrasound; optical coherence tomography; percutaneous coronary intervention; vulnerable plaque.

Figure 1

Timeline of intravascular ultrasound and optical coherence tomography with advances of PCI era. A history focused on intracoronary imaging devices (IVUS and OCT). Red and blue frames indicate representative events associated with IVUS and OCT, respectively. IVUS, intravascular ultrasound; OCT, optical coherence tomography; POBA, plain old balloon angioplasty; BMS, bare-metal stent; DES, drug-eluting stent; PCI, percutaneous coronary intervention; ACC, American College of Cardiology; AHA, American Heart Association; SCAI, Society for Cardiovascular Angiography; ESC, European Society of Cardiology; EACTS, European Association for Cardio-Thoracic Surgery; MACE, major adverse cardiac events.

Figure 2

Observational abilities of IVUS and OCT in the settings of several intracoronary structures. IVUS indicates both grayscale IVUS and IVUS with radiofrequency analysis. IVUS, intravascular ultrasound; OCT, optical coherence tomography; BRS, bioresorbable scaffold; EEM, external elastic membrane.

Figure 3

Various types of arrangements of IVUS and OCT transducer. There were three types of arrangements of IVUS and OCT transducer; (A): back-to-back arrangement; (B): coplanar arrangement; (C): sequential arrangement; (D): colinear arrangement. The colinear arrangement can acquire the strictest coregistration image of IVUS and OCT in three types of arrangements. IVUS, intravascular ultrasound; OCT, optical coherence tomography.

Figure 4

CONAVI Novasight hybrid imaging catheter; external appearances. (A) A whole appearance of system body. (B) Interface module. (C) Catheter technical specifications. (D) The transducer. IVUS, intravascular ultrasound; OCT, optical coherence tomography.

Figure 5

CONAVI Novasight hybrid imaging catheter; sample images. (A) Coregistered intracoronary images of superficial atheroma in IVUS (A-1) and OCT (A-2), and corresponding histopathology (A-3). (B) Preclinical in vivo images. (C) Measurements of lumen size by the coregistered image of IVUS and OCT. By default, any measurements (areas, distances) made in an IVUS image are automatically copied over into the OCT image and vice versa. The copied measurement can be removed. IVUS, intravascular ultrasound; OCT, optical coherence tomography.

Figure 6

TERUMO hybrid IVUS–OCT catheter system; external appearances. (A) A whole appearance of system body. (B) Interface module. (C) Catheter technical specifications. IVUS, intravascular ultrasound; OCT, optical coherence tomography.

Figure 7

TERUMO hybrid IVUS–OCT catheter system; sample images. (A) Coregistered intracoronary imaging of thrombus in IVUS (A-1) and OCT (A-2) in a cadaver coronary artery. (B) Coregistered intracoronary imaging of calcification in IVUS (B-1) and OCT (B-2) in a cadaver coronary artery. (C) Fusion image of IVUS and OCT. (D) IB-IVUS image with OCT. IVUS, intravascular ultrasound; OCT, optical coherence tomography; IB, integrated backscatter.