Tumor Encasement

In patients with pancreatobiliary tumors, it is important to evaluate portal vein invasion before surgery. Whereas CT and DSA are often used for this purpose, 3D CE MR portography is also an accurate means to diagnose portal vein invasion [16, 30]. Invasion of the portal vein makes tumor resection with clear margins nearly impossible, thus removing the patient as a surgical candidate. Tumors in the pancreatic head may encase the SMV, portal vein, and medial splenic vein. Because these tumors cause biliary obstruction, they are usually detected quickly and are therefore more often re-sectable. Tumors in the body and tail of the pancreas cause less biliary obstruction and therefore frequently become larger before being detected. These tumors commonly occlude the splenic vein. Splenic vein occlusion has a tendency to produce short gastric varices which serve as venous collaterals. These can usually be seen on delayed images.

f

Fig. 16a-l. A 64 year old patient undergoing high dose chemotherapy, with portal vein thrombosis. The 3D CE MRA MIP reconstruction (a) in the portal-venous phase shows occlusion of the right branch of the portal vein (arrows). In addition, the portal vein is supplied by collaterals from the splenic vein (arrowhead), while the superior and inferior mesenteric veins are not displayed. To further evaluate the anatomic situation, sagittal (b), axial (c), and coronal (d-l) thick slab multiplanar reconstructions were prepared. The sagittal reconstruction reveals thrombus material in the superior mesenteric vein (arrow in b), while the axial reconstruction reveals additional thrombus material in the intrahepatic portions of the portal vein (arrows in c). The coronal reconstructions (d-l) reveal the full extent of the thrombosis, which affects the superior and inferior mesenteric veins as well as the splenic vein (arrows). Note the hypoperfusion of hepatic tissue due to peripheral portal vein thrombosis (arrowheads in f)

Fig. 17a, b. Extensive collateral mesenteric vessels in a patient after splenic vein thrombosis due to pancreatitis. Imaging was performed to rule out portal vein thrombosis.

The 3D CE MRA (0.1 mmol/kg Gd-BOPTA) MIP reconstruction (a) reveals an extensive number of collateral vessels (arrow) in the area of the gastric veins. In addition, collateral vessels (arrowheads) that drain blood from the splenic hilum to the abdominal wall and into the superior mesenteric vein are also visible. However, both the MIP reconstruction (a) and the volume-rendered image (b) reveal a patent portal vein with normal intrahepatic branching (arrowin b)

Fig. 17a, b. Extensive collateral mesenteric vessels in a patient after splenic vein thrombosis due to pancreatitis. Imaging was performed to rule out portal vein thrombosis.

The 3D CE MRA (0.1 mmol/kg Gd-BOPTA) MIP reconstruction (a) reveals an extensive number of collateral vessels (arrow) in the area of the gastric veins. In addition, collateral vessels (arrowheads) that drain blood from the splenic hilum to the abdominal wall and into the superior mesenteric vein are also visible. However, both the MIP reconstruction (a) and the volume-rendered image (b) reveal a patent portal vein with normal intrahepatic branching (arrowin b)

Fig. 18a-c. Cavernous transformation post portal vein occlusion. The unenhanced T2-weighted image (a) reveals multiple dilated vessels (arrows) that demonstrate flow void in the area of the liver hilum. The vessels are markedly enhanced on the corresponding post-contrast Tl-weighted image (b). This appearance is characteristic of cavernous transformation. On the 3D CE MRA MIP reconstruction (c), the cavernous transformation (arrowheads) is only faintly enhanced due to the slow flow in the vessels. This case shows that the acquisition of contrast-enhanced Tl-weighted images often provides important additional diagnostic information. Alternatively a 3D VIBE sequence can be utilized

Fig. 19. Patent surgical spleno-renal shunt performed for lowering portal hypertension in a patient with liver fibrosis and recurrent bleeding from esophageal varices.

The 3D CE MRA study reveals a patent spleno-renal shunt with clear depiction of the vein graft (arrow), the left renal vein (arrowhead) and the ICV (asterisk)

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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