The Potential Role of Optical Coherence Tomography in the Evaluation of Vulnerable Carotid Atheromatous Plaques: A Pilot Study
The decision to intervene surgically in patients with carotid artery disease is based on the presence of symptoms, along with the severity of carotid artery stenosis as assessed by ultrasound or X-ray computed tomography (CT). Optical coherence tomography (OCT) is a relatively new imaging technique that offers potential in the identification of, as well as the distinction between, stable and unstable atherosclerotic plaques. The purpose of our study was to evaluate whether OCT can be used as a noninvasive diagnostic tool to reveal the morphology of carotid stenosis from the adventitial surface of the carotid artery. To achieve this aim, excised atheromatous plaques were scanned by OCT from the external surface.
Plaques removed at carotid endarterectomy were scanned by OCT from the external surface within 72 hr of surgery and then examined histologically. The images of the histologic slides and the scans were then compared.
We examined 10 carotid endarterectomy specimens and were able to identify calcification, cholesterol crystal clefts, and lipid deposits in the OCT images with histologic correlation. The strong light scattering from the calcified tissue and cholesterol crystal clefts limited the depth of light penetration, making observation of the intimal surface and the detail of the fibrous cap difficult. However, we were able to confidently identify the absence of an atherosclerotic plaque by OCT scans even from the external surface.
The results of this pilot study demonstrate that OCT can reveal the main features of carotid stenosis but that plaque vulnerability cannot be reliably and precisely assessed if scanned from the external surface with OCT in its present form.
KeywordsCarotid artery stenosis Endarterectomy Noninvasive diagnosis Optical coherence tomography
- 5.North American Symptomatic Carotid Endarterectomy Trial (NASCET) investigators (1991) Clinical alert: Benefit of carotid endarterectomy for patients with high-grade stenosis of the internal carotid artery. National Institute of Neurological Disorders and Stroke, Stroke and Trauma Division. Stroke 22:816–817Google Scholar
- 25.Wang RK, Tuchin VV, Xu X, Elder JB (2001) Concurrent Enhancement of imaging depth and contrast for optical coherence tomography by hyperosmotic agents. J Opt Soc Am B 18:948–953Google Scholar
- 26.van der Meer FJ, Faber DJ, Baraznji Sassoon DM, Aalders MC, Pasterkamp G, van Leeuwen TG (2005) Localized measurement of optical attenuation coefficients of atherosclerotic plaque constituents by quantitative optical coherence tomography. IEEE Trans Med Imaging 24: 1369–1376PubMedCrossRefGoogle Scholar
- 31.Drexler W, Morgner U, Kartner FX, Pitris C, Boppart SA, Li XD, Ippen EP, Fujimoto JG (1999) In vivo ultrahigh-resolution optical coherence tomography. Opt Lett 24:1221–1223Google Scholar