Pre- and postoperative imaging and interventions for the meso-Rex bypass in children and young adults

Abstract

The meso-Rex bypass is a physiological and anatomical bypass procedure for relief of extrahepatic portal vein obstruction and restoration of mesenteric venous return to the liver. Most patients who are candidates for the bypass are children or young adults with portal hypertension and hypersplenism secondary to cavernous transformation of the portal vein. Most frequently, the bypass utilizes an autologous venous graft to connect the intrahepatic left portal vein to the infrapancreatic superior mesenteric vein (SMV) re-establishing first-pass portal perfusion. We describe the preoperative imaging of the 92 bypass candidates, the surgical anatomy as reflected in postoperative imaging, and the imaging of bypass complications at our institution.Preoperative imaging with US, CT and MR is directed to demonstrate patency and size of the left portal vein and SMV, to define the extent of cavernous transformation and splanchnic collaterals, and to assess for any associated abdominal vascular or solid organ abnormalities. Postoperative imaging is aimed at diagnosing meso-Rex bypass stenosis or occlusion and the interventional management of these complications.

Pattern of branching of the left portal vein: an anatomo-radiological study

“…No pediatric CT angiography was included in the analysis as well as all the vascular casts came from adult subjects. On the other hand, it should be noted, especially in pediatric population that CT angiography also involves radiation [4].…”

Assessment of surgical portosystemic shunts and associated complications: The diagnostic and therapeutic role of radiologists

“…MRA, using time-of-flight or dynamic multiphase, gadolinium enhanced imaging (Fig. 4b), is another method to evaluate shunt patency [53]. MR imaging protocol for the assessment of SPSSs typically includes anatomical assessment of the abdominal organs with pre-contrast axial, coronal and sagittal T1-weighted images, in addition to axial and coronal T2-weighted images.…”

Diagnosis and treatment guidelines for aberrant portal hemodynamics

“…Some cases show portal hypertensive gastroenteropathy and so‐called ectopic varices in the duodenum, around bile ducts, and in the lower gastrointestinal tract Imaging modality findings Ultrasonography, CT, MRI, and laparoscopy Portal‐phase of superior mesenteric arteriography.Portal obstruction is recognized in the extrahepatic region.…”

“…Portal‐phase of superior mesenteric arteriography.Portal obstruction is recognized in the extrahepatic region. Hepatopetal collateral veins are markedly developed at the liver hilum and so‐called “cavernomatous transformation” is recognized Histopathological findings Macroscopic findings of the liver: obstruction of the main portal trunk and cavernomatous changes are observed.…”

“…Portal obstruction is recognized in the extrahepatic region. Hepatopetal collateral veins are markedly developed at the liver hilum and so‐called “cavernomatous transformation” is recognized …”