Comparison of computed tomographic angiography and intraoperative mesenteric portovenography for extrahepatic portosystemic shunts

Abstract

SUMMARY 12Objectives: Comparison of intraoperative mesenteric portovenography and computed tomographic 13 angiography for the documentation of the portal vasculature in patients with single extrahepatic 14 portosystemic shunts. 15 Methods:Retrospective study of patients with extrahepatic portosystemic shunts that underwent pre-16 operative computed tomographic angiography and intra-operative mesenteric portography. Studies 17 were compared for identification of the intra-and extrahepatic portal vasculature.

Post‐temporary ligation intraoperative mesenteric portovenography: comparison with CT angiography for investigation of portosystemic shunts

“…Whether the viscosity of the contrast agent plays a role in streamlining has, to the authors’ knowledge, not been investigated. A laminar flow appearance of contrast on preligation IOMP has been observed previously, and this has been described as a potential source of variation in the appearance of the intrahepatic portal vasculature when using this imaging modality (Parry & White ). Such a laminar flow appearance was not identified on any TFL‐IOMP in this current study, and its absence was considered likely due to supra‐physiological pressures achieved by the hand injection of the contrast agent into what was effectively a closed circuit.…”

“…CTA showed a reduction in intravascular contrast enhancement when shunts involved the right gastric vein, whereas patients with this shunt type consistently had good intrahepatic vascular enhancement on TFL‐IOMP. Variation in the preoperative CTA appearance of the intrahepatic vasculature with shunts involving the right gastric vein has been described previously (Parry & White ). Briefly, preferential flow of contrast and streamlining of the contrast agent within the portal vasculature may cause blood within the portal vein to mix incompletely and remain streamlined, with discrete channels of flow permitting the liver to receive blood from discrete viscera.…”

“…Recently, the morphology of the normal extrahepatic portal vein has been compared using both IOMP and CTA, and a conclusion was reached that CTA consistently showed more detail of the extrahepatic portal vein and its tributaries (Parry & White ). In addition, in dogs and cats suffering with a congenital extrahepatic portosystemic shunt (EHPSS), the preoperative findings of CTA have been compared with the findings of shunt preligation IOMP (Parry & White ). This study concluded that preligation IOMP was consistently outperformed by preoperative CTA in all cases except those with an EHPSS involving the right gastric vein and that, as such, there could be little indication for performing preligation IOMP in cases that had already undergone diagnostic preoperative CTA (Parry & White ).…”

Survey of surgical specialists’ content preferences in radiology reports for extrahepatic portosystemic shunts

“…In recent years, multidetector row CT angiography has superseded abdominal ultrasonography for the diagnosis and characterization of extrahepatic portosystemic shunts in most veterinary referral centers, due to its superior sensitivity . Historically, nuclear scintigraphy and intraoperative mesenteric portovenography have also been used for diagnosis, with the latter remaining a common intraoperative tool . Magnetic resonance angiography has also been described for the diagnosis of extrahepatic portosystemic shunts, although is uncommonly used in veterinary practice due to cost, the need for general anesthesia and limits to spatial resolution …”

Anomalies of the Portal Venous System in Dogs and Cats as Seen on Multidetector-Row CT: An Overview and Systematization Proposal

“…Invasive techniques (e.g splenoportography) used to obtain more detailed morphological information, are nowadays replaced by computed tomography (CT) or magnetic resonance imaging (MRI) angiography. [17][18][19][20][21] Tab. 1.…”