CLINICAL STUDY: ATHEROSCLEROSIS
Visualization of coronary atherosclerotic plaques in patients using optical coherence tomography: comparison with intravascular ultrasound
Ik-Kyung Jang, MD, PhD, FACC*,*,
Brett E. Bouma, PhD ,
Dong-Heon Kang, MD* ,
Seung-Jung Park, MD, FACC||,
Seong-Wook Park, MD, FACC||,
Ki-Bae Seung, MD,
Kyu-Bo Choi, MD, FACC,
Milen Shishkov, PhD,
Kelly Schlendorf, BS,
Eugene Pomerantsev, MD, PhD*,
Stuart L. Houser, MD ,
H. Thomas Aretz, MD and
Guillermo J. Tearney, MD, PhD
* Cardiology Division, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
Wellman Laboratories of Photomedicine, Massachusett General Hospital and Harvard Medical School, Boston, Massachusetts, USA
Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
Department of Cardiology, Kangnam St. Mary’s Hospital and Catholic University of Korea, Seoul, South Korea
|| Department of Cardiology, Asan Medical Center and Ulsan University Medical College, Seoul, South Korea
Manuscript received April 25, 2001;
revised manuscript received November 5, 2001,
accepted November 28, 2001.
* Reprint requests and correspondence: Dr. Ik-Kyung Jang, Cardiology Division, Bulfinch 105, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA.
jang.ik{at}mgh.harvard.edu
 |
Abstract
|
|---|
OBJECTIVES: The aim of this study was to evaluate the feasibility and the ability of intravascular optical coherence tomography (OCT) to visualize the components of coronary plaques in living patients.
BACKGROUND: Disruption of a vulnerable coronary plaque with subsequent thrombosis is currently recognized as the primary mechanism for acute myocardial infarction. Although such plaques are considered to have a thin fibrous cap overlying a lipid pool, imaging modalities in current clinical practice do not have sufficient resolution to identify thin (<65 µm) fibrous caps. Optical coherence tomography is a new imaging modality capable of obtaining cross-sectional images of coronary vessels at a resolution of approximately 10 µm.
METHODS: The OCT images and corresponding histology of 42 coronary plaques were compared to establish OCT criteria for different types of plaques. Atherosclerotic lesions with mild to moderate stenosis were identified on angiograms in 10 patients undergoing cardiac catheterization. Optical coherence tomography and intravascular ultrasound (IVUS) images of these sites were obtained in all patients without complication.
RESULTS: Comparison between OCT and histology demonstrated that lipid-rich plaques and fibrous plaques have distinct OCT characteristics. A total of 17 IVUS and OCT image pairs obtained from patients were compared. Axial resolution measured 13 ± 3 µm with OCT and 98 ± 19 µm with IVUS. All fibrous plaques, macrocalcifications and echolucent regions identified by IVUS were visualized in corresponding OCT images. Intimal hyperplasia and echolucent regions, which may correspond to lipid pools, were identified more frequently by OCT than by IVUS.
CONCLUSIONS: Intracoronary OCT appears to be feasible and safe. Optical coherence tomography identified most architectural features detected by IVUS and may provide additional detailed structural information.
|
Abbreviations and Acronyms
| | FWHM | | FWHM | | full-width-half-maximum | | IVUS | | intravascular ultrasound | | OCT | | optical coherence tomography |
|
Autopsy studies have identified several histologic characteristics of plaques that are prone to rupture and cause acute coronary events. These vulnerable plaques possess: 1) a thin fibrous cap (<65 µm); 2) a large lipid pool; and 3) activated macrophages near the fibrous cap (1–4). Because many of the determinants of plaque vulnerability are structural abnormalities, a high-resolution imaging technique may offer promise as a method of detecting vulnerable plaques. Presently, however, a reliable method of identifying such plaques is not available.
Non-invasive imaging modalities such as magnetic resonance and computerized tomography are currently under intense investigation. Catheter-based diagnostic techniques, however, can provide structural information with higher resolution than non-invasive methods. Intravascular magnetic resonance is being actively investigated for plaque detection and characterization (5). Intravascular ultrasound (IVUS) is widely used in interventional cardiology. A recent publication suggests a correlation between the presence of echolucent zones in coronary plaques on IVUS images and acute coronary events (6). Preliminary angioscopic studies have suggested that the presence of yellow plaques with a glistening surface correlates with acute events (7). More quantitative approaches (8,9), which measure molecular absorption overtones of lipid or the Raman shift of cholesterol, may provide unique signals from vessel walls to identify large lipid pools. Based on the hypothesis that local inflammation within vulnerable plaques may lead to local elevations in temperature, a temperature-sensing catheter has been used to study temperature heterogeneity and temperature differences between atherosclerotic plaque and healthy vessel walls (10,11).
Intravascular optical coherence tomography (OCT) has recently been proposed as a high-resolution imaging method for plaque characterization (12). Optical coherence tomography is an optical analog of ultrasound imaging because it measures the amplitude of backscattered light (optical echoes) returning from a sample as a function of delay. In vitro studies have shown that the resolution of OCT (10 µm to 20 µm) can resolve the thin fibrous caps thought to be responsible for plaque vulnerability. Additionally, the intrinsic optical properties of typical plaque constituents have provided sufficient contrast in these studies for OCT to differentiate between lipid, calcium and fibrous tissue. Recent experiments performed in vivo have demonstrated intravascular OCT imaging of normal rabbit aortas (13) and swine coronary arteries (14). Here we present the first application, to our knowledge, of intracoronary OCT in living patients. The goals of this study were: 1) to demonstrate the feasibility and safety of OCT imaging in patients; and 2) to assess OCT images of human coronary pathology acquired in vivo by comparison with IVUS images obtained from corresponding locations.
|
Methods
|
|---|
The OCT system used in this study has been described previously (15). Optical coherence tomography images were acquired at either 8 (250 angular pixels x 250 radial pixels) or 4 frames per second (500 angular pixels x 250 radial pixels), displayed using a gray-scale lookup table and digitally archived. Optical coherence tomography catheters were constructed using modified 3.2F IVUS catheters. Key modifications included the insertion of a single mode optical fiber through the IVUS core and distal termination of the optical fiber by a miniature gradient index lens and a micro prism.
Before performing OCT in living patients, 42 human cadaveric coronary artery segments were imaged using both 7F and 3.2F OCT catheters in order to determine the OCT characteristics of different plaque types. Histologic sections were obtained every 50 µm and stained with Movat’s Pentachrome. Corresponding OCT images and histologic sections were compared.
Patients (n = 10, 8 men/2 women, mean age of 59) undergoing percutaneous coronary intervention were enrolled after written informed consent was obtained. The study protocol was approved by the institutional review board of the individual institutions. After stent deployment for more severely stenotic plaques, adjacent atherosclerotic lesions (n = 17) with mild to moderate stenosis in the same vessel were evaluated using IVUS (3.2F, 30-MHz, Boston Scientific, Natick, Massachusetts) and OCT. Intravascular ultrasound was performed with an automatic pullback device at a rate of 0.5 mm/s, and an OCT catheter was advanced to a previously identified site. The exact locations of the IVUS and OCT catheters were identified using different landmarks, such as side branches and angles of the vessel as well as the tip of the guide catheter and the stent edges.
In order to remove blood from the field of view and allow clear visualization of the vessel wall, OCT images were recorded during intermittent 8 to 10 cc saline flushes through the guide catheter. The total time that was added to the procedure for OCT imaging was approximately 5 to 10 min.
After the procedure, corresponding OCT and IVUS images were selected. For each OCT imaging site, the longitudinal distances along the vessel between the image plane and at least two landmarks were measured using digitally recorded angiograms and commercially available image processing software (IPLab Spectrum 3.1, Signal Analytics, Vienna, Virginia). Single IVUS frames were extracted and digitized for direct comparison with the corresponding OCT images.
The resolutions for each modality were determined by measuring the full-width-half-maximum (FWHM) of the first derivative of a single axial reflectance scan at the surface of the tissue. A total of 10 FWHM measurements were used to compute the mean and standard deviation of the axial resolution for the two modalities. This method provides the true "image resolution" and differs from previously published methods for determining the system axial point-spread function using a phantom.
An experienced observer, blinded to the OCT data set, reviewed the IVUS data using established criteria (16–19) to classify plaque type and identify image features including the presence of a plaque, echolucent regions and intimal hyperplasia. The plaque type was classified as fibrous, calcific or lipid-rich. An OCT observer, blinded to all IVUS information, reviewed all OCT images and evaluated the images with respect to the features described above, as well as the presence of the internal and external elastic laminae. The OCT observer’s interpretation of the images was based on the results of in vitro studies (criteria in Table 1).
|
Results
|
|---|
Representative OCT images and corresponding histology of different coronary plaques from 42 human coronary artery segments are shown in Figure 1. The layered structure of the normal coronary wall was absent in all OCT images of atherosclerotic plaques. Calcifications within plaques were identified by the presence of well-delineated, low backscattering heterogeneous regions (Figs. 1A and 1B). Fibrous plaques consisted of homogeneous high backscattering areas (Figs. 1C and 1D). Lipid pools were less well-delineated than calcifications and demonstrated decreased signal density and more heterogeneous backscattering than fibrous plaques (Figs. 1E and 1F). The strong contrast between lipid-rich cores and fibrous regions in OCT images allowed fibrous caps to be easily identified. The information obtained from the cadaveric coronary artery study allowed the identification of similar morphologic features in living patients.
View larger version (82K):
[in this window]
[in a new window]
|
Figure 1 Correlation between optical coherence tomography images (A, C, E) and histologic findings (B, D, F) of human coronary artery plaques obtained at autopsy. (A) Optical coherence tomography image of a plaque consists mainly of fibrous tissue documented by histology (B) with subintimal calcifications (c). (C) Optical coherence tomography image of a predominantly fibrous plaque documented by histology (D). (E) Optical coherence tomography image of a plaque with a lipid pool (lp) and an overlying dense fibrous cap (arrowheads) documented by histology (F). Areas of neovascularization (n) can be seen as open spaces within the lipid core. Optical coherence tomography scale bars, 500 µm. Movat’s Pentachrome stain for (B), (D) and (F).
|
|
All patients tolerated the procedure well without complications. The duration of clear OCT imaging after each saline purge was approximately 2 s. The maximum penetration depth of OCT imaging measured 1.25 mm versus 5 mm for IVUS. Optical coherence tomography and IVUS axial resolutions measured 13 ± 3 µm and 98 ± 19 µm, respectively. The superior resolution of OCT can be readily appreciated by comparing corresponding OCT and IVUS images showing regions of intimal hyperplasia (Figs. 2A and 2B).
View larger version (91K):
[in this window]
[in a new window]
|
Figure 2 Fibrous coronary plaque imaged in vivo by optical coherence tomography (OCT) (A) and intravascular ultrasound (IVUS) (B). (A) From 9 o’clock to 2 o’clock, this OCT image demonstrates visualization of the intima (with intimal hyperplasia [i]), media (m) and adventitia (a). The internal and external elastic laminae are visible as signal-rich lines bordering the media (inset). A plaque extending from 2 o’clock to 9 o’clock contains a homogeneous, signal-rich region consistent with a fibrous plaque (f) that is partially obscured by a guidewire shadow artifact (*). (B) In the corresponding IVUS image, the fibrous plaque (f) is also visualized. Tick marks, 1 mm.
|
|
Table 2 summarizes the correlation between OCT and IVUS findings. In 10 patients, 17 distinct vessel locations were evaluated by OCT and IVUS. An OCT image consistent with an eccentric fibrous plaque is presented in Figure 2A, with the IVUS image from the same location in Figure 2B. All plaques identified by OCT were characterized by the loss of the layered structure observed in normal vessels or vessels with intimal hyperplasia (Fig. 2A, inset). A total of 13 imaging locations were identified as fibrous plaques by IVUS. All of these sites were also identified as fibrous plaques by OCT.
Macrocalcifications were identified in four plaques by OCT (Figs. 3A and 3C) and IVUS (Figs. 3B and 3D). The contrast between calcifications and the surrounding vessel wall was often higher in IVUS images (Figs. 3B and 3D). However, the bright IVUS signal from calcifications made assessment of neighboring tissue difficult due to saturation artifact. Moreover, the attenuation of ultrasound by calcifications caused shadowing, which impaired visualization of deeper vessel wall structures and prevented accurate measurement of the depth of calcification. In contrast, OCT images allowed improved evaluation of the extent of calcifications within plaques and visualization of plaque microstructure adjacent to calcifications.
View larger version (177K):
[in this window]
[in a new window]
|
Figure 3 Calcific coronary plaques imaged in vivo by optical coherence tomography (OCT) (A, C) and intravascular ultrasound (IVUS) (B, D). (A) This OCT image shows a well delineated, heterogeneous, signal-poor region corresponding to a macrocalcification (A, arrow), also seen in the corresponding IVUS image (B, arrow). A signal-rich fibrous band (A, two arrowheads) overlying the calcification is easily identified in the OCT image but is obscured by a saturation artifact in the IVUS image. (C) A thin layer of circumferential calcification is seen in this OCT image (arrows) as a well-defined, heterogeneous, signal-poor region within the vessel wall. A side-branch (arrowhead) can be seen adjacent to the guidewire artifact (*). (D) The extent of the calcifications (arrows) and their relation to the surrounding fibrous components of the plaque are not as clearly seen in the corresponding IVUS image. The borders of the guidewire (*) artifact are marked by dotted lines in A, C. Tick marks, 1 mm.
|
|
Echolucent regions, possibly representing large lipid pools, were identified in two corresponding OCT and IVUS image pairs (Figs. 4 and 5). Comparison of the OCT and IVUS images of the signal-rich band overlying the echolucent regions demonstrates the potential for OCT to measure cap thickness with a greater degree of precision than IVUS. Optical coherence tomography also identified two additional plaques with similar characteristics that were not definitely identified by IVUS.
View larger version (91K):
[in this window]
[in a new window]
|
Figure 4 Echolucent coronary plaque imaged in vivo by optical coherence tomography (OCT) (A) and intravascular ultrasound (IVUS) (B). (A) An atherosclerotic plaque extending from 5 o’clock to 12 o’clock contains regions consistent with fibrous tissue (f) and a homogeneous, signal-poor region (arrow), which is partially obscured by a guidewire shadow artifact (*). The minimum cap (arrowhead) thickness measured 122 ± 7 µm by OCT. (B) The corresponding IVUS image shows the same echolucent region (arrow). Tick marks, 1 mm.
|
|
View larger version (93K):
[in this window]
[in a new window]
|
Figure 5 Echolucent coronary plaque imaged in vivo by optical coherence tomography (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 µm 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.
|
|
|
Discussion
|
|---|
Corresponding OCT and IVUS image pairs form a basis for validating OCT findings and comparison of the two modalities. All fibrous plaques, calcifications and echolucent regions identified by IVUS were seen in OCT images. Moreover, as compared with IVUS, OCT images provided additional morphologic information, which could be used to improve plaque characterization (Table 2). The high resolution of OCT facilitated the identification of intimal hyperplasia, the internal and external elastic laminae, and echolucent regions, architecture that can be difficult to discern by IVUS. In addition, the lack of saturation and shadowing artifacts in OCT images of calcium deposits allowed calcium within the vessel wall to be located and enabled visualization of adjacent tissues. Most importantly, the high resolution of OCT permits the measurement of thin fibrous caps (<65 µm), thought to be present in a majority of vulnerable coronary plaques (4).
Limitations of OCT.
Clear visualization of the entire vessel lumen by OCT was possible only by displacing blood with saline. Because the maximum duration of optimal imaging after a single purge was only approximately 2 s, screening long vessel segments with OCT would be difficult. One possible solution to this problem is the proximal occlusion with an occluding balloon or the placement of the flushing catheter inside the guiding catheter with subsequent continuous saline flush, a technique commonly practiced in angioscopy (7). For an accurate measurement of a total lipid pool or for the evaluation of a vessel remodeling process, the limited depth of penetration of OCT could indeed pose a problem. However, the current capabilities of OCT are well suited for the identification and study of vulnerable plaques, where the relevant morphologic features are primarily localized to within 500 µm of the luminal surface (1–4). One way to overcome this limitation of penetration is to combine OCT with other modalities capable of imaging through blood. Other techniques such as angioscopy and thermography have been shown to provide additional information that may be related to plaque vulnerability (7,10,11). Combining these modalities with OCT may render a device with improved sensitivity for detecting vulnerable coronary plaques. Finally, although the relatively slow frame rates (4 to 8 frames per second) can potentially give rise to motion artifacts, these effects were surprisingly minimal in our study.
Future role of OCT.
Identification of vulnerable plaques might lead to a therapeutic strategy specifically designed for a given patient, such as balloon angioplasty, stenting, local delivery therapy or radiation brachytherapy to prevent acute coronary syndromes (20,21). In situ OCT imaging could also advance our understanding of the intrinsic morphologic features that determine plaque vulnerability. In addition, OCT could be used to monitor structural changes that occur with plaque regression after genetic or pharmacologic intervention (22,23).
Conclusions.
Our study demonstrates the feasibility of intracoronary OCT to visualize coronary plaque microstructure in patients. The OCT images of human coronary atherosclerotic plaques obtained in vivo provide additional, more detailed structural information than IVUS. 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. The findings of this initial experience should be supported by a prospective clinical trial to test the ability of OCT to identify vulnerable plaques. Once the predictive capability of OCT is established, a trial demonstrating effective treatment could potentially contribute to the prevention of acute myocardial infarction and sudden cardiac death.
|
Footnotes
|
|---|
Supported by Whitaker Foundation, Cambridge, Massachusetts.
|
References
|
|---|
1. Falk E. Plaque rupture with severe pre-existing stenosis precipitating coronary thrombosis, characteristics of coronary atherosclerotic plaques underlying fatal occlusive thombi. Br Heart J. 1983;50:127–134[Abstract/Free Full Text]
2. Davies MJ. Detecting vulnerable coronary plaques. Lancet. 1996;347:1422–1423[Medline]
3. Lee RT, Libby P. The unstable atheroma. Arterioscler Thromb Vasc Biol. 1997;17:1859–1867[Free Full Text]
4. Virmani R, Kolodgie FD, Burke AP, et al. Lesions from sudden coronary death: a comprehensive morphological classification scheme for atherosclerotic lesions. Arterioscler Thromb Vasc Biol. 2000;20:1262–1275[Free Full Text]
5. Zimmermann-Paul GG, Quick P, Vogt HH, von Schulthess GK, Kling D, Debatin JF. High-resolution intravascular magnetic resonance imaging: monitoring of plaque formation in heritable hyperlipidemic rabbits. Circulation. 1999;99:1054–1061[Abstract/Free Full Text]
6. Yamagishi M, Terashima M, Awano K, et al. Morphology of vulnerable coronary plaques: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary event. J Am Coll Cardiol. 2000;35:106–111[Abstract/Free Full Text]
7. Uchida Y, Fumitaka N, Tomaru T, et al. Prediction of acute coronary syndromes by percutaneous coronary angioscopy in patients with stable angina. Am Heart J. 1995;130:195–203[CrossRef][Medline]
8. Jaross W, Neumeister V, Lattke P, et al. Determination of cholesterol in atherosclerotic plaques using near infrared diffuse reflection spectroscopy. Atherosclerosis. 1999;147:327–337[CrossRef][Medline]
9. Romer TJ, Brennan JF III, Fitzmaurice M, et al. Histopathology of human coronary atherosclerosis by quantifying its chemical composition with Raman spectroscopy. Circulation. 1998;97:878–885[Abstract/Free Full Text]
10. Casscells W, Hathorn B, David M, et al. Thermal detection of cellular infiltrates in living atherosclerotic plaques: possible implications for plaque rupture and thrombosis. Lancet. 1996;347:1447–1451[CrossRef][Medline]
11. Stefanadis C, Diamantopoulos L, Vlachopoulos C, et al. Thermal heterogeneity within human atherosclerotic coronary arteries detected in vivo: a new method of detection by application of a special thermography catheter. Circulation. 1999;99:1965–1971[Abstract/Free Full Text]
12. Brezinski ME, Tearney GJ, Bouma BE, et al. Optical coherence tomography for optical biopsy: properties and demonstration of vascular pathology. Circulation. 1996;93:1206–1213[Abstract/Free Full Text]
13. Fujimoto JG, Boppart SA, Tearney GJ, et al. High resolution in vivo intra-arterial imaging with optical coherence tomography. Heart. 1999;82:128–133[Abstract/Free Full Text]
14. Tearney GJ, Jang IK, Kang DH, et al. Porcine coronary artery imaging in vivo by optical coherence tomography. Acta Cardiol. 2000;55:233–237[CrossRef][Medline]
15. Bouma BE, Tearney GJ. Power-efficient nonreciprocal interferometer and linear-scanning fiber optic catheter for optical coherence tomography. Opt Lett. 1999;24:531–533[Medline]
16. Tobis JM, Mallery J, Mahon D, et al. Intravascular ultrasound imaging of human coronary arteries in vivo: analysis of tissue characterizations with comparison to in vitro histological specimens. Circulation. 1991;83:913–926[Abstract/Free Full Text]
17. Yamagishi M, Umeno T, Hongo Y, et al. Intravascular ultrasonic evidence for importance of plaque distribution (eccentric vs. circumferential) in determining distensibility of the left anterior descending artery. Am J Cardiol. 1997;79:1596–1600[CrossRef][Medline]
18. Mintz GS, Kent KM, Pichard AD, et al. Contribution of inadequate arterial remodeling to the development of focal coronary artery stenoses: an intravascular ultrasound study. Circulation. 1997;95:1791–1798[Abstract/Free Full Text]
19. Fitzgerald PJ, St. Goar FG, Connolly AJ, et al. Intravascular ultrasound imaging of coronary arteries: is three layers the norm? Circulation. 1992;86:154–158[Abstract/Free Full Text]
20. Teirstein PS, Massullo V, Jani S, et al. Catheter-based radiotherapy to inhibit restenosis after coronary stenting. N Engl J Med. 1997;336:1697–1703[Abstract/Free Full Text]
21. Willerson JT, Buja LM. Cause and course of acute myocardial infarction. Am J Med. 1980;69:903–914[CrossRef][Medline]
22. Ganz P, Creager A, Fang JC, et al. Pathogenic mechanisms of atherosclerosis: effect of lipid lowering on the biology of atherosclerosis. Am J Med. 1996;101:4A10S–16S[Medline]
23. Feldman LJ, Isner JM. Gene therapy for the vulnerable plaque. J Am Coll Cardiol. 1995;26:826–835[Abstract]
This article has been cited by other articles:
|
|
|
|
 
A. Tanaka, T. Imanishi, H. Kitabata, T. Kubo, S. Takarada, T. Tanimoto, A. Kuroi, H. Tsujioka, H. Ikejima, K. Komukai, et al.
Lipid-rich plaque and myocardial perfusion after successful stenting in patients with non-ST-segment elevation acute coronary syndrome: an optical coherence tomography study
Eur. Heart J.,
June 1, 2009;
30(11):
1348 - 1355.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. A. Sheth, J. M. Tam, M. A. Maricevich, L. Josephson, and U. Mahmood
Quantitative Endovascular Fluorescence-based Molecular Imaging through Blood of Arterial Wall Inflammation
Radiology,
June 1, 2009;
251(3):
813 - 821.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. U Farooq, A. Khasnis, A. Majid, and M. Y Kassab
The role of optical coherence tomography in vascular medicine
Vascular Medicine,
February 1, 2009;
14(1):
63 - 71.
[Abstract]
[PDF]
|
|
|
|
|
|
|
J. A. Goldstein
Coronary plaque characterization by computed tomographic angiography: present promise and future hope.
J. Am. Coll. Cardiol. Img.,
February 1, 2009;
2(2):
161 - 163.
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Tanaka, T. Imanishi, H. Kitabata, T. Kubo, S. Takarada, T. Tanimoto, A. Kuroi, H. Tsujioka, H. Ikejima, S. Ueno, et al.
Morphology of Exertion-Triggered Plaque Rupture in Patients With Acute Coronary Syndrome: An Optical Coherence Tomography Study
Circulation,
December 2, 2008;
118(23):
2368 - 2373.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. J. Tearney, S. Waxman, M. Shishkov, B. J. Vakoc, M. J. Suter, M. I. Freilich, A. E. Desjardins, W.-Y. Oh, L. A. Bartlett, M. Rosenberg, et al.
Three-dimensional coronary artery microscopy by intracoronary optical frequency domain imaging.
J. Am. Coll. Cardiol. Img.,
November 1, 2008;
1(6):
752 - 761.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. E. Muller and S. R. Dixon
Googling the coronary: fiberoptics and a computer provide the answers.
J. Am. Coll. Cardiol. Img.,
November 1, 2008;
1(6):
762 - 764.
[Full Text]
[PDF]
|
|
|
|
|
|
|
O C Raffel, T Akasaka, and I-K Jang
Cardiac optical coherence tomography
Heart,
September 1, 2008;
94(9):
1200 - 1210.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J.-S. Kim, J.-S. Kim, E.-Y. Choi, D. Choi, and Y. Jang
Catastrophic Thrombus Formation During Optical Coherence Tomography
Circulation,
August 5, 2008;
118(6):
e101 - e102.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Ohayon, G. Finet, A. M. Gharib, D. A. Herzka, P. Tracqui, J. Heroux, G. Rioufol, M. S. Kotys, A. Elagha, and R. I. Pettigrew
Necrotic core thickness and positive arterial remodeling index: emergent biomechanical factors for evaluating the risk of plaque rupture
Am J Physiol Heart Circ Physiol,
August 1, 2008;
295(2):
H717 - H727.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
O. C. Raffel, F. M. Merchant, G. J. Tearney, S. Chia, D. D. Gauthier, E. Pomerantsev, K. Mizuno, B. E. Bouma, and I.-K. Jang
In vivo association between positive coronary artery remodelling and coronary plaque characteristics assessed by intravascular optical coherence tomography
Eur. Heart J.,
July 2, 2008;
29(14):
1721 - 1728.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
L Meng, B Lv, S Zhang, and B Yv
In vivo optical coherence tomography of experimental thrombosis in a rabbit carotid model
Heart,
June 1, 2008;
94(6):
777 - 780.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Sawada, J. Shite, H. M. Garcia-Garcia, T. Shinke, S. Watanabe, H. Otake, D. Matsumoto, Y. Tanino, D. Ogasawara, H. Kawamori, et al.
Feasibility of combined use of intravascular ultrasound radiofrequency data analysis and optical coherence tomography for detecting thin-cap fibroatheroma
Eur. Heart J.,
May 1, 2008;
29(9):
1136 - 1146.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B X Chen, F Y Ma, W Luo, J H Ruan, W L Xie, X Z Zhao, S H Sun, X M Guo, F Wang, T Tian, et al.
Neointimal coverage of bare-metal and sirolimus-eluting stents evaluated with optical coherence tomography
Heart,
May 1, 2008;
94(5):
566 - 570.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Y. Suzuki, F. Ikeno, T. Koizumi, F. Tio, A. C. Yeung, P. G. Yock, P. J. Fitzgerald, and W. F. Fearon
In Vivo Comparison Between Optical Coherence Tomography and Intravascular Ultrasound for Detecting Small Degrees of In-Stent Neointima After Stent Implantation
J. Am. Coll. Cardiol. Intv.,
April 1, 2008;
1(2):
168 - 173.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Di Mario and P. Barlis
Optical Coherence Tomography: A New Tool to Detect Tissue Coverage in Drug-Eluting Stents
J. Am. Coll. Cardiol. Intv.,
April 1, 2008;
1(2):
174 - 175.
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Kubo, T. Imanishi, S. Takarada, A. Kuroi, S. Ueno, T. Yamano, T. Tanimoto, Y. Matsuo, T. Masho, H. Kitabata, et al.
Implication of plaque color classification for assessing plaque vulnerability a coronary angioscopy and optical coherence tomography investigation.
J. Am. Coll. Cardiol. Intv.,
February 1, 2008;
1(1):
74 - 80.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F Prati, M Zimarino, E Stabile, G Pizzicannella, T Fouad, R Rabozzi, A Filippini, J Pizzicannella, M Cera, and R De Caterina
Does optical coherence tomography identify arterial healing after stenting? An in vivo comparison with histology, in a rabbit carotid model
Heart,
February 1, 2008;
94(2):
217 - 221.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Kubo, T. Imanishi, S. Takarada, A. Kuroi, S. Ueno, T. Yamano, T. Tanimoto, Y. Matsuo, T. Masho, H. Kitabata, et al.
Assessment of Culprit Lesion Morphology in Acute Myocardial Infarction: Ability of Optical Coherence Tomography Compared With Intravascular Ultrasound and Coronary Angioscopy
J. Am. Coll. Cardiol.,
September 4, 2007;
50(10):
933 - 939.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Ohayon, O. Dubreuil, P. Tracqui, S. Le Floc'h, G. Rioufol, L. Chalabreysse, F. Thivolet, R. I. Pettigrew, and G. Finet
Influence of residual stress/strain on the biomechanical stability of vulnerable coronary plaques: potential impact for evaluating the risk of plaque rupture
Am J Physiol Heart Circ Physiol,
September 1, 2007;
293(3):
H1987 - H1996.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. Nakazawa, A. V Finn, and R. Virmani
Virtual histology: does it add anything?
Heart,
August 1, 2007;
93(8):
897 - 898.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
O. C. Raffel, G. J. Tearney, D. D. Gauthier, E. F. Halpern, B. E. Bouma, and I.-K. Jang
Relationship Between a Systemic Inflammatory Marker, Plaque Inflammation, and Plaque Characteristics Determined by Intravascular Optical Coherence Tomography
Arterioscler. Thromb. Vasc. Biol.,
August 1, 2007;
27(8):
1820 - 1827.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. Matsumoto, J. Shite, T. Shinke, H. Otake, Y. Tanino, D. Ogasawara, T. Sawada, O. L. Paredes, K.-i. Hirata, and M. Yokoyama
Neointimal coverage of sirolimus-eluting stents at 6-month follow-up: evaluated by optical coherence tomography
Eur. Heart J.,
April 2, 2007;
28(8):
961 - 967.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Waxman, F. Ishibashi, and J. E. Muller
Detection and Treatment of Vulnerable Plaques and Vulnerable Patients: Novel Approaches to Prevention of Coronary Events
Circulation,
November 28, 2006;
114(22):
2390 - 2411.
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Ferencik, R. C. Chan, S. Achenbach, J. B. Lisauskas, S. L. Houser, U. Hoffmann, S. Abbara, R. C. Cury, B. E. Bouma, G. J. Tearney, et al.
Arterial Wall Imaging: Evaluation with 16-Section Multidetector CT in Blood Vessel Phantoms and ex Vivo Coronary Arteries
Radiology,
September 1, 2006;
240(3):
708 - 716.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. De Caterina and M. Zimarino
Coronary artery remodelling in atherosclerosis: unfortunately unpredictable
Eur. Heart J.,
August 1, 2006;
27(15):
1761 - 1763.
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Kawasaki, B. E. Bouma, J. Bressner, S. L. Houser, S. K. Nadkarni, B. D. MacNeill, I.-K. Jang, H. Fujiwara, and G. J. Tearney
Diagnostic Accuracy of Optical Coherence Tomography and Integrated Backscatter Intravascular Ultrasound Images for Tissue Characterization of Human Coronary Plaques
J. Am. Coll. Cardiol.,
July 4, 2006;
48(1):
81 - 88.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. S. Vasan
Biomarkers of Cardiovascular Disease: Molecular Basis and Practical Considerations
Circulation,
May 16, 2006;
113(19):
2335 - 2362.
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Aoki, A. C. Abizaid, P. W. Serruys, A. T.L. Ong, E. Boersma, J. E. Sousa, and N. Bruining
Evaluation of Four-Year Coronary Artery Response After Sirolimus-Eluting Stent Implantation Using Serial Quantitative Intravascular Ultrasound and Computer-Assisted Grayscale Value Analysis for Plaque Composition in Event-Free Patients
J. Am. Coll. Cardiol.,
November 1, 2005;
46(9):
1670 - 1676.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. K. Nadkarni, B. E. Bouma, T. Helg, R. Chan, E. Halpern, A. Chau, M. S. Minsky, J. T. Motz, S. L. Houser, and G. J. Tearney
Characterization of Atherosclerotic Plaques by Laser Speckle Imaging
Circulation,
August 9, 2005;
112(6):
885 - 892.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
I.-K. Jang, G. J. Tearney, B. MacNeill, M. Takano, F. Moselewski, N. Iftima, M. Shishkov, S. Houser, H. T. Aretz, E. F. Halpern, et al.
In Vivo Characterization of Coronary Atherosclerotic Plaque by Use of Optical Coherence Tomography
Circulation,
March 29, 2005;
111(12):
1551 - 1555.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Madjid, A. Zarrabi, S. Litovsky, J. T. Willerson, and W. Casscells
Finding Vulnerable Atherosclerotic Plaques: Is It Worth the Effort?
Arterioscler. Thromb. Vasc. Biol.,
October 1, 2004;
24(10):
1775 - 1782.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. D. MacNeill, I.-K. Jang, B. E. Bouma, N. Iftimia, M. Takano, H. Yabushita, M. Shishkov, C. R. Kauffman, S. L. Houser, H.T. Aretz, et al.
Focal and multi-focal plaque macrophage distributions in patients with acute and stable presentations of coronary artery disease
J. Am. Coll. Cardiol.,
September 1, 2004;
44(5):
972 - 979.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. A Schaar, J. E Muller, E. Falk, R. Virmani, V. Fuster, P. W Serruys, A. Colombo, C. Stefanadis, S Ward Casscells, P. R Moreno, et al.
Terminology for high-risk and vulnerable coronary artery plaques
Eur. Heart J.,
June 2, 2004;
25(12):
1077 - 1082.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J Rogowska, N A Patel, J G Fujimoto, and M E Brezinski
Optical coherence tomographic elastography technique for measuring deformation and strain of atherosclerotic tissues
Heart,
May 1, 2004;
90(5):
556 - 562.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. A. Schaar, C. L. de Korte, F. Mastik, C. Strijder, G. Pasterkamp, E. Boersma, P. W. Serruys, and A. F.W. van der Steen
Characterizing Vulnerable Plaque Features With Intravascular Elastography
Circulation,
November 25, 2003;
108(21):
2636 - 2641.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. E. Sobel, D. J. Taatjes, and D. J. Schneider
Intramural Plasminogen Activator Inhibitor Type-1 and Coronary Atherosclerosis
Arterioscler. Thromb. Vasc. Biol.,
November 1, 2003;
23(11):
1979 - 1989.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Naghavi, P. Libby, E. Falk, S. W. Casscells, S. Litovsky, J. Rumberger, J. J. Badimon, C. Stefanadis, P. Moreno, G. Pasterkamp, et al.
From Vulnerable Plaque to Vulnerable Patient: A Call for New Definitions and Risk Assessment Strategies: Part I
Circulation,
October 7, 2003;
108(14):
1664 - 1672.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. D. MacNeill, H. C. Lowe, M. Takano, V. Fuster, and I.-K. Jang
Intravascular Modalities for Detection of Vulnerable Plaque: Current Status
Arterioscler. Thromb. Vasc. Biol.,
August 1, 2003;
23(8):
1333 - 1342.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B E Bouma, G J Tearney, H Yabushita, M Shishkov, C R Kauffman, D DeJoseph Gauthier, B D MacNeill, S L Houser, H T Aretz, E F Halpern, et al.
Evaluation of intracoronary stenting by intravascular optical coherence tomography
Heart,
March 1, 2003;
89(3):
317 - 320.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. J. Tearney, H. Yabushita, S. L. Houser, H. T. Aretz, I.-K. Jang, K. H. Schlendorf, C. R. Kauffman, M. Shishkov, E. F. Halpern, and B. E. Bouma
Quantification of Macrophage Content in Atherosclerotic Plaques by Optical Coherence Tomography
Circulation,
January 7, 2003;
107(1):
113 - 119.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. M. Yelbuz, M. A. Choma, L. Thrane, M. L. Kirby, and J. A. Izatt
Optical Coherence Tomography: A New High-Resolution Imaging Technology to Study Cardiac Development in Chick Embryos
Circulation,
November 26, 2002;
106(22):
2771 - 2774.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
H. Yabushita, B. E. Bouma, S. L. Houser, H. T. Aretz, I.-K. Jang, K. H. Schlendorf, C. R. Kauffman, M. Shishkov, D.-H. Kang, E. F. Halpern, et al.
Characterization of Human Atherosclerosis by Optical Coherence Tomography
Circulation,
September 24, 2002;
106(13):
1640 - 1645.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
Top
Abstract
Methods