Optical coherence tomography assessment of vessel wall degradation in thoracic aortic aneurysms

Real, Eusebio; Eguizabal, Alma; Pontón, Alejandro; Díez, Marta Calvo; Val-Bernal, J. Fernando; Mayorga, Marta; Revuelta, José M.; López‐Higuera, José Miguel; Conde, Olga M.

doi:10.1117/1.jbo.18.12.126003

“…The textural analysis of OCT image sections of the media layer of the aortic wall revealed the anomalies present in the wall micro-structure. In [16] an identification rate with a sensitivity-specificity of 90%-86% was reached. Now, the aim of the present study is to improve this identification outcome and to gain insight of the degradation of the aortic wall validating the OCT analysis with the physiological analysis provided by conventional histopathology.…”

Section: Introductionmentioning

confidence: 98%

“…The system response has been characterized. The obtained Point Spread Function (PSF) and sensitivity decay within depth have been taken into account and a correction is applied for every acquired image [16]. The probe lens focal point is placed on the surface of the sample in order characterize the media layer from the surface.…”

Section: Optical Coherence Tomographymentioning

confidence: 99%

See 1 more Smart Citation

Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

Real¹,

Val-Bernal²,

Revuelta³

et al. 2014

Biomed. Opt. Express

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Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels. The OCT indicator of degradation depends on the dimension of areas of the media layer where backscattered reflectivity becomes smaller due to a disorder on the morphology of elastin, collagen and smooth muscle cells (SMCs). Efficient pre-processing of the OCT images is required to accurately extract the dimension of degraded areas after an optimized thresholding procedure. OCT results have been validated against conventional histological analysis. The OCT qualitative assessment has achieved a pair sensitivity-specificity of 100%-91.6% in low-high degradation discrimination when a threshold of 4965.88µm 2 is selected. This threshold suggests to have physiological meaning. The OCT quantitative evaluation of degradation achieves a correlation of 0.736 between the OCT indicator and the histological score. This in-vitro study can be transferred to the clinical scenario to provide an intraoperative assessment tool to guide cardiovascular surgeons in open repair interventions.

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“…The dimensions and severity of degradation in the aorta wall were measured by expert pathologists, providing the degradation state of the affected regions, quantified with a degradation histology score [1,15], grading from null degradation (score 0) to severe degradation (score 15).…”

Section: Histological Analysismentioning

confidence: 99%

Hessian analysis for the delineation of amorphous anomalies in optical coherence tomography images of the aortic wall

Real

¹

,

Val‐Bernal

²

,

Revuelta

³

et al. 2016

Biomed. Opt. Express

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Abstract:The aortic aneurysm is a disease originated mainly in the media layer of the aortic wall due to the occurrence of degraded areas of altered biological composition. These anomalous regions affect the structure and strength of the aorta artery, being their occurrence and extension proportional to the arterial vessel health. Optical Coherence Tomography (OCT) is applied to obtain cross-sectional images of the artery wall. The backscattering mechanisms in tissue make aorta images difficult to analyze due to noise and strong attenuation with penetration. The morphology of anomalies in pathological specimens is also diverse with amorphous shapes and varied dimensions, being these factors strongly related with tissue degradation and the aorta physiological condition. Hessian analysis of OCT images from aortic walls is used to assess the accurate delineation of these anomalous regions. A specific metric of the Hessian determinant is used to delineate degraded regions under blurry conditions and noise. A multiscale approach, based on an anisotropic Gaussian kernel filter, is applied to highlight and aggregate all the heterogeneity present in the aortic wall. An accuracy estimator metric has been implemented to evaluate and optimize the delineation process avoiding subjectivity. Finally, a degradation quantification score has been developed to assess aorta wall condition by OCT with validation against common histology.

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“…Optical Coherence Tomography (OCT) can be applied to visualize tissue within depth of few millimeters, enabling to see a region of the media layer [4]. Anomalous tissue regions produce different backscattering intensity profiles when imaged with OCT due to the invasive appearance of acidic polysaccharides and mucopolysaccharides within a typical ordered microstructure of parallel lamellae of smooth muscle cell, elastin and collagen fibers.…”

Section: Introductionmentioning

confidence: 99%

Enhanced delineation of degradation in aortic walls through OCT

Real

¹

,

Val-Bernal

²

,

Revuelta

³

et al. 2015

Self Cite

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Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels or in aortas prone to aortic dissections. The degeneration in vessel walls appears as lowreflectivity areas due to the invasive appearance of acidic polysaccharides and mucopolysaccharides within a typical ordered microstructure of parallel lamellae of smooth muscle cells, elastin and collagen fibers. An OCT indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker offers a real-time clinical insight of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable SNR conditions on the measurement process, etc. Degraded areas could be outlined by basic thresholding techniques taking advantage of disorders evidences in Bscan images, but this delineation is not always optimum and requires complex additional processing stages. This work proposes an optimized delineation of degraded spots in vessel walls, robust to noisy environments, based on the analysis of the second order variation of image intensity of backreflection to determine the type of local structure. Results improve the delineation of wall anomalies providing a deeper physiological perception of the vessel wall conditions. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.

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Optical coherence tomography assessment of vessel wall degradation in thoracic aortic aneurysms

Cited by 17 publications

References 24 publications

Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

Hessian analysis for the delineation of amorphous anomalies in optical coherence tomography images of the aortic wall

Enhanced delineation of degradation in aortic walls through OCT

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