Evaluate the value of diffusion weighted MRI in the differential diagnosis of liver cystic lesions

Abstract

Simple cysts of the liver are relatively common, accounting for about 2.5% of the population. Hydatid cysts are usually asymptomatic and are discovered by chance on ultrasound. Diagnosis of hydatid cysts is usually performed by positive ultrasound and serologic features. On MRI, distinct morphologic features of types 1, 2, and 3 of hydatid cysts are useful in the differential diagnosis of fully fluid hydatid cysts from simple cysts. Typical MRI sequences do not distinguish type 1 cysts from simple cysts. Diffusion-weighted MRI or DW-MRI is a technique that is sensitive to molecular diffusion in tissues. For this reason, we decided to investigate the diagnostic value of DW-MRI in cystic liver lesions and to distinguish simple liver cysts from hydatid cysts. Methods: Fifty patients with a diagnosis of liver cyst without definitive diagnosis are referred to Imam Reza Hospital for 20 months. Cysts with histopathology of abscess, hydatid cyst, and simple sac will be excluded. Other cysts including calcified cysts as well as cysts containing solid components are included in the statistical analysis. The cysts will also be diagnosed and classified by serology, histopathology and sonography. Non-echo cysts will be classified as simple cysts if they are asymptomatically negative and the types of hydatid cyst lesions will be classified according to the appearance of the ultrasound and serological tests. All of the above patients undergo MRI. In addition to standard sequences, ADC-MAP images will be obtained from all patients in addition to standard DW sequences. They will then be followed for one year in terms of surgery, drug or follow up. Results: In this study, 51 patients with liver cyst were diagnosed and a total of 96 cysts were studied. Mean age of patients was 46.7±17.9 years. Among the 96 cysts, ultrasound results showed 26 Hedatid cysts (27.1%) and 62 simple cysts (64.6%). MRI results showed 44 hydatid cysts (45.8%) and 52 simple cysts (54.2%). Of the 96 cysts available, follow-up and pathology showed that 40 patients had hydatid cysts (41.6%), 55 patients had simple cysts (57.3%) and one patient (1%) had metastases. Sensitivity, specificity, positive and negative predictive values for MRI were 97.5%, 90.9%, 88.6% and 96.2%, respectively. Of the 40 hydatid cysts studied, 6 (15%) were type 1 cysts, 17 (42.5%) were type 2 cysts, 10 (25%) were type 3 cysts, 6 (15%) were type 4 cysts, and one (2.5%). %) was type 5 cyst. The mean ADC value between hydatid cysts was 2.501±0.534 and that between simple cysts was 2.869±0.324, which was statistically significant (P <0.001). The difference in ADC value observed in hydatid cysts and simple cysts was statistically significant (P <0.001). The area under the diagram was calculated for simple cysts with 0.743 which was statistically significant (P <0.001) and with cutoff point of 2.764 the sensitivity and specificity were 69.1% and 63.1%, respectively.