Three-Dimensional Tissue Strain Measurement Using a Row–Column Array During Biaxial Testing of Excised Ventricular Porcine Myocardium

Figures

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  Figure 1.. (A) Top view photograph of an excised square sample of right ventricular myocardium loaded into the BMT device. Schematics of measurement configurations using (B) 3D ultrasound examination, and (C) optical camera imaging.

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  Figure 2.. X-Z cross-section of the 3D ultrasound image and triplane views of displacement vector components throughout the specimen volume for (A–D) the maximum stretch for 1:1 aspect ratio protocol of the LV specimen, and (E–H) the maximum stretch for 1:2 aspect ratio protocol of the right ventricular specimen. Lateral, axial, and elevational displacement refer to displacement in the X,Z, and Y directions, respectively.

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  Figure 3.. (A–D) In-plane and out-of-plane strain components computed from 3D ultrasound images (solid curves) for the left ventricular specimen under 1:1 loading (A, B) and the right ventricular specimen under 1:2 loading (C, D). Dashed curves in (A) and (C) are optical camera-derived strain (ground truth). (E) Bland–Altman representation of all in-plane strain measurements EXX,EYY, and EXY (blue circles); solid and dashed horizontal lines are mean difference and ± one standard deviation of difference. Root mean square error is 1.6% strain.

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  Figure 4.. The second Piola–Kirchhoff stresses SXX and SYY versus mean positive principal strain E1,2 from 3DUST for the (A) LV specimen in a 1:1 stretch protocol, (B) LV in a 1:2 protocol, (C) RV specimen in a 1:1 protocol, and (D) RV in the 1:2 protocol. Curves are straight lines meant to guide the eye between measured data points.