Model-based vascular elastography improves the detection of flow-induced carotid artery remodeling in mice

Figures

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  Figure 1. Hemodynamic changes in carotid arteries determined by ultrasound in FVB mice two weeks after ligation. (A) Representative 3D-images of the lumen of the sham-operated (SHAM) or ligated (LIGATED) mice. LCA, left carotid artery. RCA, right carotid artery. Arrows show direction of the blood flow. (B) Carotid lumen volume, mm3. (C) Carotid blood flow velocity rate, mm/s. (D) Carotid blood flow volume rate, mL/min. (E) Carotid shear stress, dynes/cm2. Black bars are LCA. Open bars – RCA. SHAM and LIGATED mice are shown on X-axis. Values are mean ± SEM. *p < 0.05 vs. LCA, SHAM. †p < 0.05 vs. RCA, SHAM. #p < 0.05 vs. RCA, LIGATED. n = 5–6 per group.

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  Figure 2. Ultrasound profiles of the carotid artery wall in FVB mice two weeks after ligation. (A) A representative image of the ligated carotid artery in an ultrasonography M-mode. A bidirectional arrow and a number define carotid artery wall thickness. LCA, left carotid artery. (B) Carotid artery wall thickness, mm. (C) Carotid artery pulsatility index. (D) Carotid artery resistive index. (E) Carotid artery strain, %. Black bars – left carotid artery (LCA). Open bars – right carotid artery (RCA). SHAM and LIGATED mice are shown on X-axis. Values are mean ± SEM. *p < 0.05 vs. LCA, SHAM. #p < 0.05 vs. RCA, LIGATED. n = 5–6 per group.

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  Figure 3. Elastography profiles of the carotid arteries in FVB mice after ligation. (A) Computed sonograms of the carotid arteries at 2 weeks after sham operation. (B) Computed sonograms of the carotid arteries at 2 weeks after ligation. LCA, left carotid artery. RCA, right carotid artery. The Young’s modulus is color-coded: lowest (zero) is set in blue; highest value (54 kPa) is in red. (C) Quantitative analysis of the Young’s modulus at 1 week post-surgery. (D) Quantitative analysis of the Young’s modulus at 2 weeks post-surgery. Black bars – LCA. Open bars – RCA. SHAM and LIGATED mice are shown on X-axis. Values are mean ± SEM. *p < 0.05 vs. LCA, SHAM. #p < 0.05 vs. RCA, LIGATED. n = 5 per group.

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  Figure 4. Reconstruction of the carotid remodeling in FVB mice after ligation. (A) Representative cross-sections of the left carotid artery (LCA) and right carotid artery (RCA) from sham-operated (SHAM) or ligated (LIGATED) mice. Magnification is 20x. Bar is 100 μm. (B) A drawing showing carotid artery at the bifurcation point. Series of cross-sections marked with grey perpendicular lines (every 200 μm) are covering 2,000 μm carotid artery length. Arrow shows direction of blood flow. 3D-reconstruction of the carotid artery compartments based on series of histological sectioning. It was not possible to measure the intimal layer in non-ligated arteries. Carotid compartments are color-coded: black is lumen area, yellow is intimal area, red is medial area, and green is adventitial area. (C) Carotid artery component volumes: lumen, intima, media, and adventitia. Black bars - LCA. Open bars - RCA. SHAM and LIGATED mice are shown on X-axis. Values are mean ± SEM. *p < 0.05 vs. LCA, SHAM; †p < 0.05 vs. RCA, SHAM. ‡p < 0.05 vs. RCA, LIGATED. n = 5–6.

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  Figure 5. Relationships between the Young’s modulus and the left carotid remodeling in FVB mice after ligation. Open squares are sham-operated animals (SHAM). Black squares are ligated mice (LIGATED). Intima volume (A) and Intima/Media Ratio (B) positively correlate with the Young’s modulus. It was not possible to measure the intimal layer in non-ligated arteries. (C) The carotid strain negatively correlated with the Young’s modulus. n = 5.