Discussion: The application of imaging studies to patients with gynaecological malignancies was still in its infancy until the introduction of cross-sectional imaging techniques occurred, including computed tomography (CT) and magnetic resonance imaging. The reported accuracy of MRI is superior to CT in assessing tumor size, defining parametrial and vaginal invasion, and even detecting regional lymph node involvement. CT should be used only when the patient is less able to tolerate the MRI study or when the latter technique is not readily available.
With further advent of functional MRI, MRI undoubtedly is the imaging modality of choice in pelvic malignancies. Diffusion-weighted imaging–ADC mapping provides information about the functional environment of water in tissues, thereby augmenting the morphologic information provided by conventional MR imaging. Detected changes include shifts of water from extracellular to intracellular spaces, restriction of cellular membrane permeability, increased cellular density and disruption of cellular membrane depolarization. These findings are commonly associated with malignancies; therefore, diffusion-weighted imaging has many applications in oncologic imaging, providing functional information to complement the excellent anatomic detail provided by MR imaging and thereby aiding in tumor detection and characterization and in the prediction and assessment of response to therapy.
When diffusion-weighted MR imaging is used in gynaecologic applications, cervical cancers have been shown to have significantly lower apparent diffusion coefficient (ADC) values compared with normal cervical tissue. Similar findings have been noted in endometrial cancers, with a tendency toward lower ADC values in higher-grade lesions. In addition, diffusion-weighted MR imaging shows promise as a biomarker for treatment response, with increasing ADC values noted in cervical carcinomas responding to radiation therapy. Diffusion-weighted MR imaging also shows promise in discriminating between benign and malignant lesions within the myometrium and endometrial cavity and in detecting peritoneal dissemination of gynaecologic tumours.