Assessing the effects of time on cadaveric facial anatomy using conventional photogrammetry, stereophotogrammetry and computed tomography

Body donation remains critically important for anatomical science, allowing examination of biological structures with three-dimensional (3D) context. However, body donors (cadavers) are a time-limited resource and the scarcity of body donors has prompted an interest in digital body preservation. Multiple imaging techniques (e.g., conventional photogrammetry [CPG], stereophotogrammetry [SPG] and computed tomography [3DCT]) can capture the 3D characteristics of a specimen indefinitely. Digital anatomical records provide an opportunity to measure anatomical structures in the absence of the physical specimen. In 2022, the face of a preserved body donor was digitally reconstructed using CPG and 3DCT. 28 months later, a repeat survey was performed using SPG and a series of facial landmarks were directly measured. The accuracy and stability of facial soft-tissues over time were measured using Euclidean landmark distances and cloud-to-mesh techniques. The results show that anatomical models produced by 3DCT and CPG produce similar facial measurements to those acquired by SPG and direct measurement at later timepoints. These data indicate that chemical fixation adequately stabilises facial anatomy over time, each sensor can be used interchangeably for facial measurement and models can be co-registered with minimal discrepancy.