Imaging techniques for the pre-surgical diagnosis of adnexal tumours

A correct diagnosis of any adnexal mass is essential to triage women to appropriate treatment pathways. Several imaging techniques are available that may be used to provide an assessment of a mass before treatment, such as transvaginal ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography combined with computed tomography. In this chapter, we focus in depth on the role of transvaginal ultrasonography, as current evidence suggests it is the most appropriate initial imaging investigation to identify and characterise any mass if present in women suspected of having adnexal pathology. Subjective assessment by an experienced ultrasound examiner is the optimal approach to diagnose masses, followed by risk models and rules developed by the International Ovarian Tumor Analysis study. A group of tumours has proven difficult to classify with transvaginal ultrasound, and remain a diagnostic challenge for which accurate second-stage tests would be of value. Some studies suggest that magnetic resonance imaging (MRI), compared with other imaging modalities, may play a role in the assessment of this cohort of 'difficult to classify' adnexal masses. These studies, however, did not report quality of transvaginal ultrasonography (i.e. experience level of the examiner) and lacked uniformity in describing the criteria used to define such 'difficult' masses. On the basis of standardised terminology developed by the International Ovarian Tumor Analysis study to describe adnexal masses, as well as prediction models and rules developed in the course of the study, we propose new criteria that we can use to clearly define complex or 'difficult to classify' adnexal masses to focus the role for second-line imaging tests, such as conventional magnetic resonance imaging combined with dynamic contrast-enhanced or diffusion-weighted sequences on masses where further tests other than ultrasonography would be of value.