Changes in carotid artery texture by ultrasound and elastin features in a murine model

Carol Mitchell; Rashid Al Mukaddim; Yuming Liu; Melissa Graham; Jens C Eickhoff; Ashley M Weichmann; Matthew C Tattersall; Claudia E Korcarz; James H Stein; Tomy Varghese; Kevin W Eliceiri

doi:10.3389/fcvm.2023.1215449

Changes in carotid artery texture by ultrasound and elastin features in a murine model

Front Cardiovasc Med. 2023 Jul 25:10:1215449. doi: 10.3389/fcvm.2023.1215449. eCollection 2023.

Authors

Carol Mitchell^{1

2}, Rashid Al Mukaddim², Yuming Liu³, Melissa Graham⁴, Jens C Eickhoff⁵, Ashley M Weichmann⁶, Matthew C Tattersall¹, Claudia E Korcarz¹, James H Stein¹, Tomy Varghese², Kevin W Eliceiri^{2

3

7

8}

Affiliations

¹ Department of Medicine, University of Wisconsin-Madison, Madison, WI, United States.
² Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States.
³ Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, United States.
⁴ Comparative Pathology Laboratory, Research Animal Resources and Compliance, University of Wisconsin-Madison, Madison, WI, United States.
⁵ Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, United States.
⁶ Carbone Cancer Center, Small Animal Imaging and Radiotherapy Facility, University of Wisconsin-Madison, Madison, WI, United States.
⁷ Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.
⁸ Morgridge Institute for Research, Madison, WI, United States.

Abstract

Objective: In humans, arterial grayscale ultrasound texture features independently predict adverse cardiovascular disease (CVD) events and change with medical interventions. We performed this study to examine how grayscale ultrasound texture features and elastin fibers change in plaque-free segments of the arterial wall in a murine model prone to atherosclerosis.

Methods: A total of 10 Apoe^tm1Unc/J mice (n = 5 male, n = 5 female) were imaged at 6, 16, and 24 weeks of age. Two mice were euthanized at 6 and 16 weeks and the remaining mice at 24 weeks. Texture features were extracted from the ultrasound images of the distal 1.0 mm of the common carotid artery wall, and elastin measures were extracted from histology images. Two-way analysis of variance was used to evaluate associations between week, sex, and grayscale texture features. Texture feature and elastin number comparisons between weeks were conducted using the sex-by-week two-way interaction contrasts. Sex-specific correlations between the number of elastin fibers and grayscale texture features were analyzed by conducting non-parametric Spearman's rank correlation analyses.

Results: Arterial wall homogeneity changed significantly in male mice from 6 to 24 weeks, with a mean (SD) of 0.14 (0.03) units at 6 weeks and 0.18 (0.03) units at 24 weeks (p = 0.026). Spatial gray level dependence matrices-homogeneity (SGLD-HOM) also correlated with carotid artery plaque score (r_s = 0.707, p = 0.033). Elastin fibers in the region of interest decreased from 6 to 24 weeks for both male and female mice, although only significantly in male mice. The mean (SD) number of elastin fibers for male mice was 5.32 (1.50) at 6 weeks and 3.59 (0.38) at 24 weeks (p = 0.023). For female mice, the mean (SD) number of elastin fibers was 3.98 (0.38) at 6 weeks and 3.46 (0.19) at 24 weeks (p = 0.051).

Conclusion: Grayscale ultrasound texture features that are associated with increased risk for CVD events in humans were used in a murine model, and the grayscale texture feature SGLD-HOM was shown to change in male mice from 6 weeks to 24 weeks. Structural alterations of the arterial wall (change in elastin fiber number) were observed during this time and may differ by sex.

Keywords: atherosclerosis; carotid; elastin quantification; pre-clinical murine model; texture features; ultrasound imaging.

Abstract

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