Quantitative measurement from vascular casts.

Area of Science:

• Biomedical Engineering
• Vascular Biology
• Materials Science

Background:

• Casting materials exhibit significant shrinkage (0.2-20%) and wide viscosity ranges (1.4-100,000 cP).
• Blood vessels possess complex and variable mechanical properties, with differing responses to pressure changes in diameter and length.
• Perfusion fixation alone does not fully preserve native vascular dimensions.

Purpose of the Study:

• To evaluate vascular casting as a method for accurate measurement of the vasculature.
• To identify critical parameters for minimizing dimensional errors during vascular casting.
• To assess the accuracy of measuring atherosclerotic lesions using aortic casts.

Main Methods:

• Review of quantitative measurements of casting material properties.
• Analysis of blood vessel mechanical properties under varying pressures.
• Assessment of dimensional changes in fixed dog carotid arteries.
• Evaluation of measurement error in periorificial atherosclerotic lesions from aortic casts.

Main Results:

• Casting materials vary widely in shrinkage and viscosity.
• Vascular dimensions are sensitive to pressure, with significant variability in length changes.
• Glutaraldehyde-fixed dog carotid arteries retain elastic recoil (approx. 20% circumferentially, 30% longitudinally).
• A ~10% measurement error was observed for periorificial atherosclerotic lesions from aortic casts.

Conclusions:

• Vascular casting is recommended for accurate vasculature measurement when using low-shrinkage resins and maintaining physiologic transmural pressures.
• Careful technique is essential to mitigate casting-induced dimensional errors.
• Further research is needed on the effects of vascular smooth muscle tone during casting.