The role of ADC measurement in differential diagnosis of focal hepatic lesions.

PURPOSE: To evaluate the utility of apparent diffusion coefficient (ADC) measurement in characterization of focal solid hepatic lesions and determine the role of ADC values in differentiation of solid benign and solid malignant hepatic lesions.
MATERIALS AND METHODS: Between June 2006 and December 2010, a total of 95 focal solid hepatic lesions in 95 consecutive patients were evaluated by abdominal MRI. Diffusion weighted MRI was performed with b 100, b 600 and b 1000 gradients with ADC measurements. Comparison of mean ADC values between solid benign (focal nodular hyperplasia and other solid benign lesions) and solid malignant lesion (hepatocellular carcinoma, metastasis, and cholangiocarcinoma) groups and between each benign and malignant lesion was done. The ROC analyses were performed in order to determine cut-off ADC values for differentiation of benign and malignant lesion groups at 3 different gradients.
RESULTS: Twenty-six of 95 lesions were benign and 69 were malignant. Mean ADC values of solid benign lesions at b 100, b 600 and b 1000 gradients were 2.25±0.54×10(-3), 1.97±0.64×10(-3) and 1.52±0.47×10(-3) mm2/s, respectively. Mean ADC values of solid malignant lesions at b 100, b 600 and b 1000 gradients were 1.84±0.57×10(-3), 1.37±0.38×10(-3) and 1.08±0.22×10(-3) mm2/s, respectively. The ADC values of solid benign lesions were significantly higher than solid malignant lesions at all 3 gradients (P<0.05). Differentiation of benign and malignant subtype lesions from each other in their groups did not yield as significant findings as comparing results between benign and malignant lesions.
CONCLUSION: Although ADC measurements were not helpful for differentiating subtypes of solid benign or solid malignant lesions, ADC measurements at 3 different gradients may be useful in differential diagnosis of benign lesions from malignant ones.