That finding comes from a systematic quantitative review of studies on the topic performed by Dr. Maria I. Rosa, with the University of Extremo Sul Catarinense, in Criciuma, Brazil, and colleagues, and published online November 8th in the American Journal of Obstetrics & Gynecology.
“A new MRI technique with dynamic diffusion-weighted imaging (DWI) is a useful tool for characterizing epithelial ovarian tumors and can help distinguish among benign, borderline, and invasive tumor,” the authors explain. Also, “Morphologic criteria such as septa, papillary projections, solid portion, and T2- weighted MRI signal intensity of solid tissue are useful for discriminating invasive from noninvasive ovarian tumor.”
To assess the accuracy of MRI in the diagnosis of ovarian cancer, the researchers analyzed data from 15 studies that compared MRI findings with paraffin section histology in a total of 1267 ovarian masses. In this data set, 65.4% of ovarian masses were benign, 5.7% were borderline tumors, and 28.9% were invasive tumors.
The team found that with a positive MRI result, the likelihood ratio of a malignant or borderline tumor versus a benign lesion was 6.6. Looked at another way, the pretest probability of cancer increased from 32% overall to 77% with a positive MRI result and decreased to 4.8% with a negative result, according to the report.
“This systematic review showed that MRI (1.5 T) has sensitivity of 92%, specificity of 85%, and an AUC of 0.95 for the detection of borderline or invasive ovarian tumors,” the authors state.
The ability of MRI to predict whether a pelvic mass is benign or malignant “is of great value,” Dr. Rosa and colleagues conclude. “Benign ovarian masses can be managed with more conservative approaches, either with close observation or with laparoscopic surgery,” they point out. “On the contrary, when a tumor is malignant, there is a need for urgent laparotomy.”
Accuracy of magnetic resonance imaging in ovarian tumor: a systematic quantitative review
Am J Obstet Gynecol 2010.