Diffusion-Weighted MR Imaging of the Benign Hepatic Focal Lesions

Abstract

Purpose: To determine the role of diffusion weighted MR imaging and apparent diffusion coefficient (ADC) in benign hepatic focal lesions. Method and Materials: This study included 47 patients (29 M, 18 F with mean age of 43 years) with benign hepatic focal lesions. They were cyst (n = 8), hemangioma (n = 23), abscess (n = 5), adenoma (n = 5), focal nodular hyperplasia (n = 4) and nodular regenerative hyperplasia (n = 2). They underwent routine MR imaging and diffusion MR weighted imaging using 1.5 tesla MR unit (Symphony-Siemens). Diffusion MR imaging was done using spin echo type of single shot echo planar imaging (EPI) with b value of 0, 500 & 1000 sec/mm2. The apparent diffusion coefficient (ADC) map was reconstructed and ADC value was measured. The mean ADC values correlated with histo-pathological results as well as follow-up imaging results. Results: Adequate ADC maps were obtained in 47 patients. The mean ADC values were 3.4 ± 0.12 × 10-3 mm2/sec in cystic lesion, 2.23 ± 0.08 × 10-3 mm2/sec in hemangioma, 1.94 ± 0.05 × 10-3 mm2/sec in abscess, 1.72 ± 0.07 × 10-3 in focal nodular hyperplasia, 1.65 ± 0.06 × 10-3 mm2/sec in adenoma, 1.62 ± 0.07 × 10-3 mm2/sec in nodular regenerative hyperplasia. The mean ADC values were significantly different within benign hepatic focal lesions (P < 0.001). The differences between the mean ADC values of FNH, adenoma and NRH were not statistically significant (P < 0.23). Conclusion: Diffusion weighted MR imaging is a new imaging modality for diagnosis and characterization of different benign hepatic focal lesions, particularly in patient with renal dysfunction.