No abstract

On multisection dynamic magnetic resonance (MR) images obtained in the arterial-dominant phase, the authors have occasionally noted the presence of an early-enhancing pseudolesion, which is not a hypervascular tumor, in the medial segment of the left hepatic lobe. Multisection dynamic MR imaging was performed in 185 patients with suspected liver disease. A suspect early-enhancing pseudolesion was present in six of the 185 patients. In all six patients, the pseudolesion was located in the subcapsular portion adjacent to the porta hepatis in the medial segment of the left hepatic lobe. Corroborative and follow-up studies failed to demonstrate any evidence of a pathologic condition, therefore justifying the term "pseudolesion." Radiologists should be aware of the possibility of the presence of this early-enhancing pseudolesion in this typical location on multisection dynamic MR images, because such a finding may be misinterpreted as a true lesion.

space.A, Dynamic CT scan shows replaced right hepatic artery originating from superior mesenteric artery as a high-density structure

The purpose of this study is to clarify the changes of peripheral normal liver parenchyma before and after ethanol injection, with respect to MR appearances and pathologic findings and, in so doing, to clinically evaluate the therapeutic effectiveness of percutaneous ethanol injection (PEI) therapy. The normal liver in 12 rabbits was injected with ethanol. We performed conventional and dynamic MR imaging and prepared the histopathologic specimens 1 week (group 1), 2 weeks (group 2), and 1 month (group 3) after ethanol injection. On conventional MR images, coagulative necrosis in the normal liver was demonstrated as an area of low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in all groups. On dynamic MR images, contrast enhancement in the coagulative necrosis was not seen in groups 1 and 2; however, gradual and concentric enhancement was seen in the direction of the central necrotic portion from early-to-delayed phase image in group 3. Although signal intensity of the coagulative necrotic area in the normal liver after ethanol injection may mimic that of untreated or viable hepatocellular carcinoma (HCC) when clinically encountered on conventional MR images, coagulative necrosis of the normal liver parenchyma will be discriminated from viable HCC by using dynamic MR imaging.

Background. Case 1. Case 2. Conclusion.