Focal eosinophilic infiltration versus metastasis in the liver: comparison of MRI findings.

Abstract

BACKGROUNDS/AIMS: This article was studied to compare the MRI findings of focal hepatic eosinophilic infiltration and hepatic metastasis.

METHODOLOGY: Contrast enhanced MR images of 40 lesions in 15 patients with focal hepatic eosinophilic infiltration and 34 lesions in 17 patients with liver metastasis were reviewed retrospectively. The size, number and location of focal lesions were analyzed. The lesion-to-liver contrast difference of each lesion was recorded using region of interest (ROI) curve on T1- and T2-weighted images. Enhancement pattern was classified into homogenous, rim-enhancement and heterogeneous enhancement. All the images were reviewed by two gastrointestinal radiologists in consensus.

RESULTS: Focal eosinophilic infiltration and hepatic metastasis showed predominantly low signal intensity on T1WI and high signal intensity on T2WI. However, focal eosinophilic infiltration manifested as iso signal intensity, more frequently than hepatic metastasis on T1WI (42.5% vs. 0%). Metastasis showed more frequently high signal intensity on portal (94.1% vs. 57.5%) and delayed phase (94.1% vs. 45.0%) comparing with focal eosinophilic infiltration. The lesion-to-liver contrast was greater in metastasis on both images (19 +/- 17 vs. 8 +/- 6 on T1WI and 21 +/- 19 vs. 13 +/- 10 on T2WI). Rim enhancement pattern is more frequently seen in metastasis on all phases. Seventeen (43%) focal eosinophilic infiltrations showed rim enhancement on arterial or portal venous phase and homogenous enhancement on delayed phase.

CONCLUSION: MRI findings to favor eosinophilic infiltration include subcapsular location, lesser lesion-to-liver contrast on T1 and T2 weighted image and early rim enhancement with layed homogenous enhancement.