Perilesional enhancement of hepatic metastases: correlation between MR imaging and histopathologic findings-initial observations

PURPOSE: To correlate perilesional enhancement on gadolinium-enhanced magnetic resonance (MR) images with histopathologic findings in patients with hepatic metastases. MATERIALS AND METHODS: In seven patients with histopathologically proved hepatic metastases, MR images obtained before and early and late after the administration of gadopentetate dimeglumine were retrospectively evaluated for perilesional enhancement. The thickness of hepatic parenchyma with intense perilesional enhancement was calculated. The thickness of the histologic tumor border (the zone separating the outermost border of the tumor nodule from the surrounding hepatic parenchyma) also was measured. RESULTS: In three patients, early gadolinium-enhanced images showed prominent perilesional enhancement, which correlated with a thick tumor border containing peritumoral desmoplastic reaction, peritumoral inflammation, and vascular proliferation at histopathologic examination. In one patient, mild perilesional enhancement was shown. At histopathologic examination, the lesion periphery showed moderate peritumoral changes. In the remaining three patients, no perilesional enhancement was observed, and at histopathologic examination there was a thin tumor border that contained minimal to mild perilesional changes. The thickness of hepatic parenchyma with intense perilesional enhancement on early gadolinium-enhanced images showed a strong positive correlation with tumor border thickness at histopathologic examination (r = 0.99). CONCLUSION: Intense perilesional enhancement of metastases on early gadolinium-enhanced MR images correlates with histopathologic hepatic parenchymal changes, which include peritumoral desmoplastic reaction, inflammatory cell infiltration, and vascular proliferation.