Indeterminate adnexal masses at ultrasound: effect of MRI imaging findings on diagnostic thinking and therapeutic decisions.

OBJECTIVE

To determine the impact of MRI including DWI on therapeutic decision-making and costs in the work-up of patients with a indeterminate adnexal mass on ultrasound.

METHODS

Thirty-eight patients with indeterminate ovarian lesions scheduled for surgery were included in this prospective study. In a questionnaire, the surgeon characterised the lesions based on a morphological score and determined the surgical procedure. The assessment was re-evaluated knowing MR findings and correlated with the final diagnosis. A cost-benefit analysis of MRI was performed. The impact of including DWI in the MR protocol was assessed.

RESULTS

MRI provided major diagnostic information in 11/38 cases (28.9%) resulting in abstention from surgery in 5 cases; moderate additional information was recorded in 10/38 (26.3%) patients. Overall a net cost saving (3'676 EUR) was achieved. DWI did not show a significant difference between benign and malignant lesions. Teratomas yielded significantly lower mean ADC values (0.597 × 10(-3) mm(2)/s) compared with all other adnexal lesions (1.812 × 10(-3) mm(2)/s); the mean ADC values in endometrioma (1.387 × 10(-3) mm(2)/s) were significantly lower than in other cystic lesions (2.372 × 10(-3) mm(2)/s).

CONCLUSION

Inclusion of MRI in the diagnostic algorithm of the indeterminate adnexal mass allows better differentiation of ovarian lesions resulting in a change of therapeutic decision-making with net cost savings.