ULTRASONOGRAPHIC APPEARANCE OF THE CISTERNA CHYLI IN THE DOG

Introduction/Aims
The cisterna chyli (CC) is a dilated and bipartite portion of the lymphatic channels coursing intimately along the abdominal aorta in the retroperitoneal space.1 The appearance of the CC of the dog has been described on magnetic resonance imaging.2 The aim of this poster is to describe the ultrasonographic appearance of the CC in 2 dogs with chylous ascitis and in 2 healthy dogs.
Methods
Abdominal ultrasonography was realised with a 7.5MHz microconvex transducer. A right or left lateral dorsal approach was used. The aorta (together with the cranial mesenteric artery in normal dogs) was used as the main landmark to localize the CC. The dogs with chylous ascites were a 4 year old female american cocker spaniel, with immune-mediated hemolytic anemia and thrombocytopenia and a 1 year old, spayed female whippet with recurrent pancreatitis. The 2 healthy dogs were a 7 year old Beagle and a 9 year old Jack Russell. The abdominal ultrasonography was realised within 2 hours after the meal in the healthy dogs.
Results
The CC was seen as a hypoechoic structure, without detectable flow, dorsal and to the right of the aorta. The CC was easily visible in the 2 dogs with chyloabdomen while it was more difficult to localize in the healthy dogs. The CC was tubular on the longitudinal images. On transverse images, the CC is elliptic or semilunar and may partially surround the aorta. The maximal width of the CC measured on transverse images varied from 2-3mm in the 2 healthy dogs to 4-8mm in the 2 dogs with chyloabdomen. In 3 patients some efferent/afferent lymphatic vessels were seen as thin hypoechoic tubes converging on the CC. Shape and size of the CC in the same animal were seen varying during the same ultrasonography or between different exams.
Discussion/Conclusion
The CC is visible by ultrasonography in dogs. Its visibility depends on different conditions like disease of the lymphatic system3, quality and distance of the meal.