Type:
Educational Exhibit
Keywords:
Paediatric, Abdomen, Liver, Catheter arteriography, CT, Ultrasound, Balloon occlusion, Contrast agent-intravenous, Arteriovenous malformations, Congenital, Not applicable
Authors:
M. J. MORENO, L. Riaza Martin, E. Vazquez, I. Diez Miranda, L. Riera, A. Coma; BARCELONA/ES
DOI:
10.26044/ecr2020/C-08312
Findings and procedure details
Ultrasound (US) is the first line of diagnosis, as it is a noninvasive and radiation-free alternative. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) confirm the diagnosis and provide vascular information not available in a US examination. Finally, angiography can clarify cases in which the diagnosis is uncertain, especially angiography with occlusion test, and treat the shunt through an occlusive device placed in the shunt. Closing the shunt through interventional radiology is preferred whenever possible (Fig. 25).
Imaging evaluation of CPSS:
- US (Fig. 21): In most cases, it will be an evaluation of a child with nonspecific symptoms. The US is useful to identify the MPV (or absence thereof), its branches, the direction of Doppler flow and in some cases demonstrate the shunt. In extrahepatic CPSS it is difficult to see the shunt, but an absent or small MPV will hint at its existence [2]. It is also used to identify accompanying abnormalities. When the abnormalities are identified, it is always useful to complete the study with additional imaging. [1,3].
- CT and MR imaging (Fig. 22, Fig. 23): Contrast-enhanced CT angiography and MR angiography both provide a map of the portal vessels and characterize complications (hepatic tumors, liver parenchymal derangements) or other malformations. MR must always be considered the first choice, as it is radiation-free [3,8].
- Angiography (Fig. 24): Conventional angiography is considered the standard for the diagnosis of CPSS. It provides the most accurate depiction of the portal, hepatic and abnormal vessels imaging can muster. The technique usually used is indirect mesenteric portovenography, during the visceral phase of the mesenteric arterial angiography. When this is not enough to map the portal circulation or show the shunt(s), a direct transhepatic portography may be performed. During the angiography it is also possible conducting the occlusion test, which consists of the placement of a balloon close to the shunt, without occluding the MPV, and measuring the portal and IVC pressure before and after the occlusion. The test is useful especially in extrahepatic CPSS, to demonstrate the presence of extremely hypoplastic or ectopic portal vein, not observed in non-invasive imaging, and the measurement of portal pressure provides information that will help guide the treatment [4,8].