Introduction

MR imaging is increasingly being used in gynaecological and pelvic imaging due to its high contrast resolution compared to CT and ultrasound. As MR imaging techniques continue to improve, its role continues to evolve. Consequently, MRI is proving useful in characterising adnexal masses and may have a role in defining the extent of disease in ovarian cancer.

Technique

Optimal imaging in ovarian cancer requires a high-field system with good gradients in order to obtain rapid and high-resolution images. Imaging acquisition is further enhanced by the use of phased-array coils that are compatible with parallel imaging techniques. These techniques use some of the spatial information contained in the individual elements of a radiofrequency (RF) receiver coil array to increase imaging speed [1].

For characterisation of adnexal masses, images should be obtained in at least two planes to assist in determining the organ of origin of the mass. Both T1- and T2-weighted images are important for pelvic anatomy and in tissue characterisation. The use of small field of view high-resolution images improves the delineation of small structures such as papillary projections. Fat-suppression sequences help to distinguish fatty from haemorrhagic masses. Fat-saturated chemical shift techniques are preferable to STIR sequences. This is to avoid confusion between fat and haemorrhagic lesions, as haemorrhagic lesions may have the same T1 relaxation time as fat on the STIR sequence. Gadolinium-enhanced fat-suppressed T1-weighted images improve lesion characterisation by increasing the conspicuity of nodules and septa in complex adnexal masses [2–5].