The role of diffusion-weighted MRI in the classification of liver hydatid cysts and differentiation of simple cysts and abscesses from hydatid cysts.

PURPOSE The purpose of this study is to identify the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the classification of liver hydatid cysts (HCs) and their differentiation from simple cysts and liver abscesses. MATERIALS AND METHODS Twenty-two patients that were sent to our department with preliminary diagnoses of HCs or abscess were included in the study. Thirty lesions were evaluated. MRI included T1-weighted fast gradient echo, T2-weighted half-Fourier acquisition single-shot turbo spin echo, and DW single-shot echo planar pulse sequencing (b, 0, 50, and 1000 s/mm²). The apparent diffusion coefficient (ADC) values (mm²/s) of the HCs, abscesses, and simple cysts were calculated. RESULTS No statistically significant difference was found between the ADC values of type 1 and 3 (P > 0.05) HCs and of simple cysts and type 1 HCs (P > 0.05). The ADC values of abscesses were significantly lower than those of type 1 and type 3 HCs, and simple cysts. No statistically significant difference was found between the ADC values of abscesses and type 4 HCs (P > 0.05). Type 4 lesions exhibited significantly lower ADC values in comparison to type 1 and 3 HCs. CONCLUSION DW-MRI helps differentiate type 4 lesions from other cysts and can distinguish abscesses from hydatid cysts other than type 4 as well as from simple cysts. Type 1 HCs cannot be differentiated from simple cysts using ADC values alone, and type 4 lesions are indistinguishable from abscesses.