Volumetric measurement and three-dimensional reconstruction of feline paranasal sinuses by using computed tomography images with semi-automatic segmentation

Sinonasal diseases are common in cats and diagnosis is challenging due to similarity of clinical symptoms and complex anatomical structure. Paranasal sinuses of cats evaluated 2D by computed tomography (CT) on previous studies. In human medicine, evaluation of paranasal sinus by CT based segmentation is gold standart. Recent studies in human medicine emphasize the importance of 3D evaluation and volumetric measurements of paranasal sinuses, demonstrating their potential contibution to the diagnosis. This study aims to promote the routine use of CT based segmentation in evaluation of cat paranasal sinuses. In this study, CT images of 20 cats without paranasal sinus pathology were used. The CT images were obtained using a Fujifilm Supria model CT scanner with 32 slices. Skull length measurements were performed on sagittal plane, skull width measurements were obtained on dorsal plane 2D CT images. Three-dimensional views and volume measurements of paranasal sinuses were obtained CT based segmentation by using the 3D Doctor software. The morphometric structures and anatomical variations of paranasal sinuses were evaluated 2D and 3D. Descriptive statistics including mean, standard error, median, first quartile, third quartile, minimum, and maximum were summarized for weight, age, skull width, skull length, frontal sinus volume, and sphenoid sinus volume data obtained during the study. Possible relationships between continuous variables were examined using Pearson correlation analysis. A significance level of p<0.05 was considered in all statistical analyses. The CT images of 20 cats were used. The average age of the cats was 69.7±11.16 months, and their average weight was 3.96±0.21 kg. Among the images included in the study, 55% belonged to female cats and 45% to male cats. In the 3D evaluation of all cases anatomical variations were detected in both frontal and sphenoid sinuses in. Asymmetry between the right and left cavities was observed in 10% of frontal sinuses. Mild septal deviation was detected in 12 frontal sinuses. Vertical septa were found in all frontal sinuses, while horizontal septa were observed in 65% of frontal sinuses. An oblique, eccentrically located septum within the sphenoid sinus waw observed 90%. One septa was detected in 5% of sphenoid sinuses. The average frontal sinus volume was 2579.23±211.3 mm³, and the average sphenoid sinus volume was 330.25±31.74 mm³. There was a statistically significant difference in frontal and sphenoid sinus volumes between female and males. Significant positive correlation was found between frontal and sphenoid sinus volumes (p<0.05). Significant positive correlation was found between frontal sinus volume and skull lenght. In this study 15% of the frontal sinuses were hypoplastic, 70% were normal pneumatized, and 15% were hyperplastic. 20% of the sphenoid sinuses are hypoplastic, 65% are normal pneumatized, and 15% are hyperplastic. Three-dimensional volume and morphometric evaluation of cat paranasal sinuses important due to complex anatomical structure, with irregular extensions in three-dimensional planes, and high individual anatomical variations of paransal sinuses. We believed that CT-based segmentation in the evaluation of paranasal sinuses can contribute to the diagnosis of sinonasal diseases in veterinary medicine.