Morphological and morphometric features of the endocranial caste in the domestic cat: A reconstructive cone-beam ct study

The endocranial cast, which provides important information about the endocranial cavity and the brain, has been investigated in many vertebrate species for many years. Although various methods have been used in its preparation, the most preferred method today is the production of digital endocranial casts using computed tomography images. Our knowledge about the morphology and morphometry of the endocranial cast of the domestic cat, which is currently the most kept pet species worldwide, is quite limited. The aim of this study was to prepare a digital endocranial cast of the domestic cat whose head region was imaged using cone-beam computed tomography (CBCT), to determine its morphometric characteristics, and to describe the anatomical structures located on the cast. In this retrospective study, DICOM datasets with slice thicknesses of 0.2 mm and 0.3 mm obtained by CBCT from ten female and ten male adult domestic cats were used. The datasets were first evaluated using a DICOM viewer program to determine their suitability according to the research criteria. Each animal's dataset was then imported into an open-source medical modeling software (3D Slicer) to reconstruct a 3D model of the endocranial cast. After recording the volume and surface area data of the cast from the modeling interface, images were captured from six different views for morphological evaluation. In the final stage of the study, the datasets were re-examined in the DICOM viewer, and craniometric analyses were performed. Within this scope, eleven linear measurements and six indices related to the cranial skeleton were calculated. The data obtained from the study were evaluated using appropriate statistical analyses. Digital endocranial casts were successfully created using CBCT images and a medical modeling program. It was observed that thinner slices provided higher surface detail compared to thicker ones. The endocranial cast volume and surface area were determined as 27.7 ± 2.03 cm³ and 64.1 ± 4.47 cm² in females, and 29.0 ± 2.54 cm³ and 65.7 ± 3.77 cm² in males, respectively. The patterns observed on the dorsal and lateral surfaces of the endocranial cast were found to be highly consistent with the sulci and gyri of the brain tissue. The patterns located on the ventral surface were observed to represent the passage sites of cranial nerves. Except for the foramen magnum height, all linear measurements were higher in males, whereas index values were higher in females. No statistically significant differences were found between males and females in terms of the morphometric data obtained in the study (p> 0.05). Although this study on the digital endocranial cast of the domestic cat was conducted on a limited number of specimens, its methodology and results possess a reference value. The presented digital models may contribute to the anatomical knowledge and educational understanding of the cranial cavity.