Fig. 1

Post-contrast computed tomographic appearance of the thoracic thymus in a rabbit. a On a transverse image at the cranial border of the heart, the right dorsal thoracic thymus lobe (1a) is clearly isolated from the right ventral lobe (1c). The multilobulated heterogeneous structure of the caudal parts of the right ventral (1c) and left thoracic thymus lobes (2) is noted. A right (rcrvc) and left cranial vena cava (lcrvc) is present (ascending (a’) and descending thoracic aorta (a’’), pulmonary trunk (p)). b On a right sagittal image at the level of the right cranial vena cava (rcrvc), the separated right dorsal thoracic thymus lobe (1a) shows a round to ovoid shape with a compact structure. The right ventral thoracic thymus lobe has a small cranial (1b) and larger caudal (1c) part separated by the right internal thoracic artery (rit). Caudal to the right dorsal thoracic thymus lobe, the mediastinal lymph node (3) is seen (heart (h)). c On the dorsal plane, the left thoracic thymus lobe (2) extends more caudally in between the heart and the thoracic wall in comparison to the right ventral thoracic thymus lobe (1c). Cranial to the heart, only little lung tissue is seen on the right. Note the wide cardiac size in relation to the thoracic width (heart (h))