Objective: A high rate of false-negative sonographic examinations for evaluation for hepatic artery thrombosis in the setting of collateral artery vessel formation has been documented. Subacute hepatic artery compromise with collateral vessel formation can be subclinical, and we believe that this phenomenon may occur more commonly than currently appreciated.
Conclusion: We discuss two cases of subacute hepatic artery compromise with collateral artery vessel formation that were prospectively diagnosed in July 2007 by sonography and confirmed by angiography. We refer to this phenomenon as "collateral transformation of the hepatic artery."