Elsevier

American Heart Journal

Volume 152, Issue 4, October 2006, Pages 755.e1-755.e4
American Heart Journal

Clinical Investigation
Imaging and Diagnostic Testing
Measurement of the thickness of the fibrous cap by optical coherence tomography

https://doi.org/10.1016/j.ahj.2006.06.030Get rights and content

Background

Identification of the fibrous cap is important because its thickness is a major determinant of plaque vulnerability in lipid-rich plaque. Thus, a high-resolution imaging technique may be a promising method for the identification of the fibrous cap within lipid-rich plaque. The purpose of this study was to investigate the feasibility of using optical coherence tomography (OCT) to measure the thickness of the fibrous cap within lipid-rich plaque.

Methods and Results

We examined 35 lipid-rich plaques from 102 coronary arterial segments of 38 human cadavers (22 men and 16 women; mean ages, 74 ± 7 years). Optical coherence tomography and corresponding histological images were digitized for measurement of the thickness of fibrous cap, and the results between OCT and histological examination were compared. There was good correlation of the thickness of the fibrous cap between OCT and histological examination (y = 0.97x + 28.49; r = 0.90; P < .001). A Bland-Altman test showed good agreement of the thickness of the fibrous cap between OCT and histological examination (mean difference, −24 ± 44 μm).

Conclusions

Optical coherence tomography provides an accurate representation of the thickness of the fibrous cap and may prove useful in assessing plaque vulnerability in lipid-rich plaque.

Section snippets

Methods

We examined 102 coronary arterial segments from 38 human cadavers (22 men and 16 women; mean ages, 74 ± 7 years). Of these 38 cadavers, 6 had symptomatic cardiovascular disease (16%). The study protocol was approved by the ethics committee of Kawasaki medical school, and written informed consent was obtained from each family. About 5 cm in length of the proximal site of the 3 major coronary arteries, including the left anterior descending coronary artery, left circumflex artery, and right

Measurement of the thickness of the fibrous cap

The thickness of the fibrous cap measured by histological examination ranged from 10 to 450 μm (mean, 138 μm). The thickness of the fibrous cap measured by OCT ranged from 10 to 430 μm (mean, 163 μm). Representative OCT image and corresponding histological image of the fibrous cap within the lipid-rich plaque are shown in Figure 1. There was good correlation of the thickness of the fibrous cap between OCT and histological examination (y = 0.97x + 28.49; r = 0.90; P < .001) (Figure 2). A

Discussion

In this study, the accuracy of OCT for measuring the thickness of the fibrous cap was tested against histological examinations and was found to be acceptable according to both the correlation study and Bland-Altman analysis. Considering the resolution of OCT, which was 10 μm, the bias of the OCT on the thickness of the fibrous cap was quite acceptable. Recently, OCT has been proposed as a high-resolution intravascular imaging method, providing accurate evaluation of not only coronary arterial

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