Renal enlargement in veterinary radiology
Renal disease is extremely common in dogs and cats. In veterinary diagnostic imaging, we use radiographs, ultrasound and sometimes special studies to determine if one or both kidneys are affected. Radiographs are often a good place to start to determine renal size and detect calculi.
The normal reference range sizes for kidneys are 2.5-3.5 x the length of L2 for dogs, and 2-3 x the length of L2 for cats. It’s measured best on the v/d projection where the kidneys remain in a more consistent position.
The left kidney usually sits caudal to the right kidney, with the cranial pole at L2 in the dog and cat. It resides in the retroperitoneal space, dorsal and lateral to the descending colon. If the left kidney enlarges, it tends to displace the descending colon medially and ventrally.
The right kidney is located dorsal to the descending duodenum and the ascending colon. Enlargement of the right kidney can cause medial and ventral displacement of the descending duodenum, and medial and ventral displacement of the ascending colon.