Cancer of the uterus: the value of MRI pre- and post-irradiation.

In cancer of the uterus, the morphologic factors influencing the choice of therapy and patient prognosis are tumor size, depth of invasion, presence of lymph node metastasis, and stage. Clinical staging is often inaccurate with resultant suboptimal therapy, thereby invalidating comparison between treatment options. The available cross-sectional imaging modalities of ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI), have significantly improved the staging of malignant disease. In the pelvis, MRI offers several advantages over the other imaging modalities. In particular, MRI has excellent soft tissue contrast resolution, allowing direct multiplanar imaging with evaluation of tumor extension in all three directions, and has variable imaging parameters (TR/TE)--characteristics of the echo patterns--to facilitate optimal tumor detection. It is a non-invasive technique with an ability to visualize blood vessels without the need for contrast injection and is independent of body habitus. However, MRI is not tissue-specific and a histological diagnosis is required in all cases. In the post-radiotherapy patient, MRI has the ability to demonstrate radiation tissue change and the potential to differentiate radiation fibrosis from recurrent/residual tumor. Its non-invasive nature and lack of ionizing radiation make it suitable for assessing treatment response and as an adjunct for patient monitoring.