SummaryA total of 39 patients with suspected primary (n = 17) or recurrent/residual (n = 22) ovarian carcinoma were investigated by pelvic magnetic resonance imaging (MRI) and immunoscintigraphy using the monoclonal antibody OC-125 labelled with Indium-111. The results of the imaging studies were compared with surgical evaluation and pathological examination of resected material in each case. In patients with suspected primary tumours, the sensitivity and specificity of MRI for the diagnosis of ovarian carcinoma was 37·5 and 66 per cent respectively, and for immunoscintigraphy 75 and 22 per cent. In patients with suspected recurrent disease, the sensitivity and specificity were 88 and 40 per cent for MRI and 82 and 60 per cent for immunoscintigraphy, compared with serum CA125 levels which had a sensitivity of 81 per cent and specificity of 50 per cent. The predictive value of a positive result was 83 per cent for MRI, 87 per cent for immunoscintigraphy and 81 per cent for serum CA125, with a negative predictive value of 50 per cent for all three techniques. These techniques are proving to be the main imaging methods for the assessment of patients with ovarian carcinoma, however, both techniques showed limitations in the detection of very small volume disease and were no more sensitive than serum CA125 in the detection of recurrence.