Diffusion Weighted MR and Apparent Diffusion Coefficient Measurement in Classification and Characterization of Noncystic Focal Liver Lesions

Abstract: The objective of this study was to assess the clinical role of apparent diffusion coefficient (ADC) analysis in noncystic focal liver lesion (FLL) classification/characterization. Six hundred liver magnetic resonances with multi-b (b¼50, 400, 800s/mm2) diffusion-weighted imaging (DwI) were retrospectively reviewed. Mean ADC was measured in 388 lesions (195 benign and 193 malignant) excluding internal necrotic areas. Cystic benign lesions were excluded from analysis. Sensitivity and specificity in distinguishing benign from malignant lesions were calculated. Analysis of variance was performed to detect differences among subgroups of solid lesions. Mean ADC of malignant lesions was 0.98010 3mm2/s, significantly (P<0.05) lower than mean ADC of benign lesions (1.43310 3mm2/s). Applying an ADC cutoff of 1.06610 3mm2/s, specificity and sensitivity for malignancy were respectively 86.6% and 73.6%. Of all lesions, >1/3 (39.5%) presented values lower than 1 10 3 mm2/s, with 90.0% chance of malignancy. Above 1.510 3mm2/s (about 20% of all lesions) chance of malignancy was 9.5%. DwI cannot assist in noncystic FLL characterization, but can help in FLL classification in about half the cases.