Protocolo para modelagem e fabricação de biomodelos de coração canino por manufatura aditiva

Abstract

Traditional veterinary anatomy teaching methods, while fundamental, face ethical and logistical challenges, such as the scarcity and degradation of cadaveric specimens. Additive Manufacturing, known as 3D printing, presents itself as a viable technological solution, allowing the creation of physical replicas from medical imaging. However, the application of this technology in the field is frequently marked by empiricism, lacking a systematic approach that guarantees anatomical fidelity and repeatability, especially for organs with complex geometry like the canine heart. This dissertation’s main objective was the development and evaluation of canine heart biomodels, and its secondary objective, the establishment of a detailed engineering protocol for their modeling and manufacturing, aimed at anatomy education. The Design Science Research methodology was adopted as a framework to guide the iterative development and evaluation process of the artifacts. The manufacturing protocol began with the selection of high-resolution, contrast-enhanced Computed Tomography images in DICOM format from two dogs of different breeds. The image segmentation stage, identified as the most critical part of the process, was executed in specialized software. The method developed to overcome segmentation difficulties consisted of a dual-mask approach: a first mask was created for the internal cavities, known as the blood pool, and a second mask was generated for the total cardiac muscle mass. A Boolean subtraction operation was then applied to merge these masks, resulting in a hollow 3D model with high anatomical fidelity. Subsequently, the 3D mesh was refined in mesh-editing software for correction and smoothing. The biomodels were then prepared in two configurations: an integral one for external study, and a sectioned one at the atrioventricular septum for internal study. The manufacturing of the biomodels, the primary artifacts of this research, was carried out using two distinct technologies: Material Extrusion with PLA filament and Vat Photopolymerization with resin. To assess the efficacy of these artifacts, the biomodels underwent a validation process by an expert panel composed of veterinary cardiologists and engineers. This evaluation was conducted through structured Likert scale questionnaires. The validation results demonstrated strong acceptance of the biomodels. The sectioned PLA models were considered excellent for teaching internal macrostructures, such as the myocardial thickness, and were valued for their robustness and low cost. The integral resin models were validated as superior in representing fine anatomical details and the complex external vasculature of the heart’s base. The main limitation identified by the specialists was the unrealistic tactile perception of the rigid materials. It is concluded that the developed biomodels are precise artifacts of high pedagogical utility. The developed protocol, in turn, proved to be an effective and reproducible engineering method, filling the methodological gap of standardization identified in the literature.