Abstract
Purpose
To assess the frequency, imaging findings, and significance of early‐enhancing nonneoplastic (EN) lesions with gadolinium‐enhanced magnetic resonance imaging (MRI) of the liver following partial hepatectomy.
Materials and Methods
We retrospectively reviewed MR images after partial hepatectomy in 30 patients. Postoperative MRI was performed in 1–12 months (mean, 3.7 months) after partial hepatectomy. We defined the EN lesion as a lesion that was ill defined; irregular, wedge shaped, or serpiginous; located along the liver edge; not visible on unenhanced MR images; did not appear hypointense on portal venous‐ or equilibrium‐phase images; or a combination of those imaging findings.
Results
A total of 39 EN lesions (size range, 5–60 mm; mean, 25.2 mm) in 19 patients and 17 recurrent tumors (size range, 5–50 mm; mean, 16.8 mm) in 10 patients newly appeared after partial hepatectomy. The EN lesions were diagnosed as pseudolesions by the second postoperative follow‐up MRI in 17 patients or contrast‐enhanced computed tomography (CT) in two. A total of 13 EN lesions (33%) were located along the liver edge and 20 (51%) were adjacent to the resected area. The shape was circular in 11 (28%), oval in three (8%), irregular in 11 (28%), wedge shaped in five (13%), and serpiginous in nine (23%). No EN lesion showed hypointensity on gadolinium‐enhanced portal venous‐phase or equilibrium‐phase images. A total of 14 EN lesions (36%) showed slight hyperintensity on T2‐weighted images. The confidence levels for malignancy probability assigned by blinded radiologists were lower with EN lesions than with recurrent tumors (P < 0.001).
Conclusion
EN lesions are frequently seen in MRI following partial hepatectomy, and occasionally are slightly hyperintense on T2‐weighted images, mimicking malignant tumors. However, most EN lesions can be correctly diagnosed with MRI findings. J. Magn. Reson. Imaging 2004;20:66–74. © 2004 Wiley‐Liss, Inc.