Computed tomography appearance of intra-thoracic lymph nodes in normal cats

Abstract

The study of the appearance of intra-thoracic lymph nodes in the cat observed on the computed tomography which divided into 3 parts as following; the feline soft cadaver, clinically normal cats and the retrospective study of the feline patients. The result showed that the computed tomographic images of feline soft tissue cadavers could not detected any intra-thoracic lymph nodes. However, based on the study on 30 clinically normal cats which were mixed breed, age ranging from 4 months to 11 years old, body weight between 1.5 to 5.7 kilogram, 12 male cats (6 castrated) and 18 female cats (10 spayed) and body condition score between 2 to 5, intra-thoracic lymph nodes could be more detected in the cat that the age was more than 7 months old. Besides, only the sternal, cranial mediastinal and tracheobronchial lymph nodes could be detected on the post-contrast enhanced CT images, but not the intercostal lymph node (6/30, 10/30, 7/30 and 0/30 nodes, respectively). The maximal wideness of the sternal, cranial mediastinal and tracheobronchial lymph node on the axial, post-contrast enhanced CT images were 4.18 ± 1.62 mm, 5.70 ± 2.41 mm and 4.30 ± 2.19 mm, respectively. Comparing between the CT machine setting, the slice thickness at the 1.25 mm showed the similar detection score of the normal intra-thoracic lymph node as that of the 0.625 mm (p > 0.05). Finally, based on the retrospective study, 9 cats were included. The intra-thoracic lymph nodes of 8 cats could not be detected, but a cat revealed a large cranial mediastinal mass.