Analysis of digital vernier caliper

Introduction: Accurately measuring tissue thickness is a crucial technical aspect and a source of bias in biomechanical analysis, as even minor errors can substantially affect stress, elasticity, and tissue behavior. This study analyzes the reproducibility and consistency of specimen thickness measurements by experienced users using a digital caliper under two protocols and a specialized device under a third, also assessing the impact on biomechanical properties. Method: The current study is a methodological study in which we examined the thickness of the porcine arterial wall, specifically segments from the aorta, carotid, and coronary arteries. For the first two protocols, thickness measurements were performed using a digital vernier caliper (Multicomp PRO MP012475), whereas a dedicated digital thickness gauge (Mitutoyo 547-500S, Kawasaki, Japan) was employed for the third protocol. Biomechanical testing was conducted using a BioTester® 5000 (CellScale, Canada), fitted with two opposing BioRakes mounted on actuators to apply uniaxial tensile loading at 25% and 50% stretch. Results: For coronary artery wall thickness measurements, significant protocol-dependent differences between novice users for Protocol 1 and Protocol 3 (p = 0.0384), and for intermediate users using the same protocols (p = 0.0122). The mechanical response of porcine vascular tissues at 25% and 50% stretch was not influenced by operator experience, as no statistically significant differences in Cauchy stress were observed among users across the three experimental protocols. Conclusion: This study demonstrates that the method used to measure arterial wall thickness influences reproducibility, particularly in thin-walled vessels such as coronary arteries, and when performed by less experienced users.