CT arterial portography: causes of technical failure and variable liver enhancement.

Objective: We studied the causes of technical failure and enhancement variability encountered during CT arterial portography.
Materials and Methods: CT arterial portograms and digital arteriograms were obtained via the superior mesenteric artery before partial liver resection in 43 patients with malignant tumors. These studies were reviewed for causes of technical failure and variable enhancement.
Results: Eleven (26%) of 43 procedures were technical failures. Causes of failure included aortic injection after catheter dislodgement (four), dense hyperenhancement associated with laminar flow in the portal vein produced by rapid venous return from a selective injection into a proximal branch vessel of the superior mesenteric artery (two), premature scanning beginning at the iliac crest (two), reflux into a replaced right hepatic artery (one), hepatic arterial enhancement via the pancreaticoduodenal arcade (one), and portal hypertension (one). Of the 32 remaining studies, 28 showed areas of parenchymal hypoenhancement or hyperenhancement. Causes of variable enhancement included impaired portal vein perfusion from mass effect of the tumor, laminar flow in the portal vein, and focal fatty infiltration.
Conclusion: Technical failures and enhancement variability are common in CT arterial portography. Factors leading to technical failure include catheter choice and position, portal hypertension, and operator error.