Characterization of Malignancy of Adnexal Lesions Using ADC Entropy: Comparison with Mean ADC and Qualitative DWI Assessment

A. S. Kierans¹, G. L. Bennett¹, T. C. Mussi¹, J. S. Babb¹, H. Rusinek¹, J. Melamed², A. B. Rosenkrantz¹

37 patients with an adnexal mass underwent pelvic MRI including DWI before resection. We evaluated performance of mean ADC, ADC entropy, and subjective interpretation of two radiologists using DWI in discriminating benign and malignant adnexal lesions. Malignant lesions demonstrated significantly higher ADC entropy than benign lesions but no significant difference in mean ADC. Accuracy of ADC entropy was similar to that of the less experienced reader. However, the more experienced readers accuracy was greater than that of all other assessments. We conclude ADC entropy may serve as a useful quantitative metric for ovarian lesion evaluation, particularly for less experienced readers.