Primary ovarian cancer: prospective comparison of contrast-enhanced CT and pre-and postcontrast, fat-suppressed MR imaging, with histologic correlation.

Sixteen patients with clinically suspected malignant ovarian disease underwent contrast agent-enhanced computed tomography (CT) and magnetic resonance (MR) imaging in a prospective comparative study. MR imaging included fat-suppressed spin-echo and breath-hold FLASH (fast low-angle shot) before and after intravenous injection of gadopentetate dimeglumine. Histologic confirmation was obtained at laparotomy (n = 13) and biopsy (n = 3). Thirteen patients had histologically proven primary ovarian cancer. MR images showed the internal architecture of ovarian tumors better than CT in nine patients and equivalently in seven. MR images showed the relationship between ovarian tumors and adjacent pelvic structures (uterus [n = 9], sigmoid colon [n = 7], bladder [n = 7], and rectum [n = 3]) better than CT in nine patients and equivalently in seven. Intraabdominal extent of disease was better defined on MR than on CT images in nine patients, equivalently in six, and worse in one. Peritoneal metastases 1-2 cm in diameter were detected on MR images and missed on CT scans in six patients. In only one case did this result in a staging error with CT. The results suggest that MR imaging is at least equivalent and may be superior to CT in the evaluation of ovarian malignancy.