Ultrasonography, computed tomography and magnetic resonance imaging in the assessment of pelvic pathology

ObjectiveUltrasound (US) is the primary imaging modality in the investigation of pelvic pathology in women however it can be very inaccurate. MRI and CT provide a more detailed pelvic examination and hence we compared their accuracies with that of ultrasound to find out if these two modalities should be used more often.Patients and methods136 women who had MRI examination of the pelvis for investigation of probable pelvic pathology were studied. Hundred and twenty-five of these women had an initial ultrasound scan and 23 had an initial CT. Diagnostic accuracy was assessed against histopathology or clinical follow-up.ResultsHistopathology was available in 127/136 women. Overall 36% of the lesions were malignant. The overall accuracy of MRI, US and CT were 97%, 77% and 87%, respectively. MRI confidently identified the tissue of origin in 94% compared to only 66% for US. There was a significant difference in accuracy between MRI and US in diagnosing adnexal and uterine pathology. MRI was better than CT and US in diagnosing peritoneal metastases whereas CT was superior in diagnosing omental infiltration.ConclusionWe suggest that all women with a pelvic abnormality identified on US or in whom there is a strong clinical suspicion of disease should undergo MR pelvic imaging in preference to CT because of its better soft tissue resolution and multi-planar capability.