2. Optical coherence tomography (OCT) is
analogous to ultrasound, measuring the
intensity of back-reflected light (near infrared
light) rather than sound (acoustical waves). An
OCT image represents a cross sectional picture
of the optical reflectance properties of tissue. 4
OCT originally developed to image the
transparent tissue of the eye with
unprecedented resolution.
3. In vitro studies have shown that the resolution of
OCT (10-20 micron) can resolve the thin fibrous caps
thought to be responsible for plaque vulnerability. 1
Catheter-based diagnostic techniques can provide
structural information with higher resolution than non-
invasive methods. OCT achieves at least 10 times
higher resolution than IVUS, and can be adapted for
catheter-based imaging of vulnerable plaque. 3
4. Brezinski, Tearney, Bouma, Fujimoto,
and colleagues in 1997 discussed the
advantages of OCT as following:
I. High resolution,
II. Broad dynamic range, and
III. Ability to be delivered through intravascular
catheters 2
6. Tearney, Jang, and colleagues showed
that in vivo OCT imaging of normal
coronary arteries, intimal dissections, and
deployed stents in swine is feasible, and
allows identification of clinically relevant
coronary artery morphology with high-
resolution and contrast. 4
7. IVUS (A) and OCT (B) images of the stented right coronary artery are shown. Although
IVUS showed a well-deployed stent, the detailed structure around the stent struts is not
well visualized. In addition, OCT clearly visualized tissue prolapse between the stent struts
(12 to 3 o’clock). The tissue prolapse occurred mainly in an area with lower OCT signal
intensity, which is suggestive of a plaque with a large lipid content. 5
Visualization of Tissue Prolapse Between
Coronary Stent Struts by OCT
Visualization of Tissue Prolapse Between Coronary Stent Struts by Optical Coherence Tomography: Comparison
With Intravascular Ultrasound ; Ik-Kyung Jang, Guillermo Tearney, and Brett Bouma
Circulation 2001 104: 2754.
8. As highlighted in VP Watch of this week,
Jang and colleagues showed the feasibility
and the ability of intravascular OCT to
visualize the components of coronary plaques
in living patients. 3
They found that compared with IVUS, OCT
images provide additional morphologic
information, which could be used to improve
plaque characterization. 3
9. Echolucent coronary plaque imaged in vivo by OCT (A) and intravascular ultrasound (IVUS) (B). (A)
This plaque demonstrates a homogeneous, signal-poor region (inset, arrow) by OCT that extends
near the vessel lumen at the shoulder of the plaque (inset, arrowheads), possibly representing a
vulnerable shoulder region. The minimum cap thickness at this region measured 20 ± 3 m by OCT.
(B) The echolucent region (arrow) is also identified in the IVUS image from the same site; but the cap
is difficult to visualize, and its thickness cannot be measured. Tick marks, 1 mm.
Ik-Kyung Jang, Brett E. Bouma, Dong-Heon Kang, Seung-Jung Park, Seong-Wook Park, Ki-Bae Seung, Kyu-Bo Choi,
Milen Shishkov, Kelly Schlendorf, Eugene Pomerantsev et al.; Visualization of coronary atherosclerotic plaques in
patients using optical coherence tomography: comparison with intravascular ultrasound, Pages 604-609 ; Journal of
the American College of Cardiology 2002; Volume 39(4): 604-609
Comparing echolucent coronary plaque
imaged in vivo by OCT and IVUS
10. Jang, Tearney, and their colleagues also compared
the OCT and IVUS images of the signal-rich band
overlying the echolucent regions and showed the
potential for OCT to measure cap thickness with a
greater degree of precision than IVUS. 3
They also identified two additional plaques by OCT
with similar characteristics that were not definitely
identified by IVUS. 3
11. Conclusion:
I. OCT represents a new technology for intracoronary
imaging because of its high resolution, broad dynamic
range, and ability to be delivered through
intravascular catheters.
II. The OCT images of human coronary atherosclerotic
plaques (in vivo) provide additional, more detailed
structural information than IVUS.
12. Conclusion:
III. The unique capability of OCT to resolve micrometer-
scale features of coronary plaques in patients
suggests that this new technique holds promise for
identifying features of coronary plaques at risk for
rupture.
13. Questions:
I. Knowing that presence of blood induces major artifact
for OCT imaging, the question is how practically OCT
catheter can be utilized for screening vulnerable
plaques throughout coronary arteries?
II. Knowing the widespread prevalence of
atherosclerotic plaque in healthy population, and
plaques with similar morphology may have different
outcome, the question is how OCT can identify active
inflamed vulnerable plaques?
14. Questions:
III. Knowing the need for imaging both structure and
activity of plaque, would it be feasible to combine OCT
and thermography or OCT and near infra red
spectroscopy?
IV. Assuming the limited use (<20%) of IVUS for plaque
characterization in cat labs is due to cost issue, would
OCT or combination of OCT and thermography/
spectroscopy be cost effective?
16. 1) Fujimoto JG, Boppart SA, Tearney GJ, Bouma BE, Pitris C, Brezinski ME.; High resolution in vivo intra-
arterial imaging with optical coherence tomography.; Heart. 1999 Aug;82(2):128-33.
2) Brezinski ME, Tearney GJ, Weissman NJ, Boppart SA, Bouma BE, Hee MR, Weyman AE, Swanson
EA, Southern JF, Fujimoto JG.; Assessing atherosclerotic plaque morphology: comparison of optical
coherence tomography and high frequency intravascular ultrasound. Heart. 1997 May;77(5):397-403.
3) Ik-Kyung Jang, Brett E. Bouma, Dong-Heon Kang, Seung-Jung Park, Seong-Wook Park, Ki-Bae Seung,
Kyu-Bo Choi, Milen Shishkov, Kelly Schlendorf, Eugene Pomerantsev et al.; Visualization of coronary
atherosclerotic plaques in patients using optical coherence tomography: comparison with intravascular
ultrasound, Pages 604-609 ; Journal of the American College of Cardiology 2002; Volume 39(4): 604-
609
4) Tearney GJ, Jang IK, Kang DH, Aretz HT, Houser SL, Brady TJ, Schlendorf K, Shishkov M, BoumaBE.
Porcine coronary imaging in vivo by optical coherence tomography. Acta Cardiol. 2000 Aug;55(4):233-7.
5) Visualization of Tissue Prolapse Between Coronary Stent Struts by Optical Coherence Tomography:
Comparison With Intravascular Ultrasound ; Ik-Kyung Jang, Guillermo Tearney, and Brett Bouma
Circulation 2001 104: 2754.
References
