Ultrasonographic assessment of the spleen in 60 healthy sheep

AIM: To evaluate the sonographic appearance, size, location and shape of the spleen in 60 healthy sheep. METHODS: A 7.5 MHz linear scanner was used to examine the location, extent and appearance of the spleen from the left side of the sheep, in intercostal spaces (ICS) 8-12 and caudal of the last rib. RESULTS: The ultrasonographic appearance of the splenic parenchyma was homogeneous with a thin, smooth echogenic capsule. The spleen could be visualized in intercostal spaces 9-12 in all sheep, in intercostal space 8 in 25/60 sheep (42%) and caudal of the last rib in 24/60 sheep (40%). In intercostal spaces 8-12 and caudal of the last rib the spleen was visible in 16/60 sheep (27 %). The distance from the dorsal margin of the spleen to the spinous processes of the thoracic vertebrae was greatest in the 8th intercostal space: mean 19.32 (SD 2.76) cm and smallest in the 12th intercostal space: mean 6.61 (SD 1.94) cm. The dorsoventral splenic extent was greatest in the 11th intercostal space: mean 13.69 (SD 2.2) cm and smallest in the 8th intercostal space: mean 7.13 (SD 2.5) cm. The thickness of the spleen ranged from 21 (SD 9.0) mm in the 8th intercostal space to 49 (SD 7.0) mm in the 11th intercostal space. The mean vessel diameter was 1.9 (SD 0.7) mm. Spleen size did not correlate with age, body weight, or thoracic and abdominal circumference. CONCLUSIONS: Ultrasonography is a useful, straightforward and non-invasive method for evaluation of the spleen in sheep. CLINICAL RELEVANCE: These findings provide information which can be used as a reference for sonographic spleen examination and diagnosis of splenic lesions in sheep.