Portosystemic shunts (PSSs) are anomalous vascular communications between the portal vein or itsbranches and the systemic venous system. Signalment, history, clinical signs, and laboratory findings canalready provide a presumptive diagnosis of a PSS. However, imaging techniques such as portography,ultrasonography (US), nuclear scintigraphy, computed tomography (CT), or magnetic resonance imaging(MRI) are required to provide a definitive diagnosis. Nuclear scintigraphy is the gold standard for detectingPSSs, but it is not useful in distinguishing the different types of shunts. Due to its high sensitivity,portography was for a long time considered the gold standard for the differentiation of PSSs, even thoughit is an invasive technique. However, the recent development of a standard protocol for ultrasound (US)and the routine use of Doppler modalities resulted in the same sensitivity as portography. Therefore, withthe additional benefit of being fast and noninvasive, US is now more commonly performed. It may be suggestedas a “new” gold standard, depending upon the experience of the radiologist. Computed tomographyand MRI provide detailed anatomic information. In this third part about portosystemic shunts in dogs andcats the different types of shunts and their diagnosis using portography will be explained.