MRI Tool Identifies Risk of Malignancy in Adnexal Masses


The O-RADS MRI tool could potentially reduce unnecessary or over-extensive surgery in patients with various types of ovarian cancer.

Researchers believe they have developed an MRI tool that can accurately identify the risk of malignancy in adnexal masses.1

The tool, when used in clinical practice, could allow for a tailored, patient-centered approach for masses that are sonographically indeterminate, preventing unnecessary surgery, less extensive surgery, or fertility preservation when appropriate, while ensuring preoperative detection of lesions with a high likelihood of malignancy. 

“There is a real unmet clinical need to find less invasive ways to identify women at risk of ovarian cancer,” Andrea G. Rockall, MRCP, FRCR, senior author of the study and Chair of Radiology at Imperial College London, said in a press release.2 “Our tool has the potential to help triage patients who are low risk so they can have less invasive treatment options, as well as identifying high risk patients so they can receive treatment at an earlier stage and have a better change of long-term survival.” 

The 5-point scoring system, which was evaluated in a study published in JAMA Network Open, is called the Ovarian Adnexal Reporting Data System Magnetic Resonance Imaging; or O-RADS MRI for short. 

In the multicenter study, a total of 1,340 women were enrolled and 1,194 of those women were found to be evaluable. Of that cohort, 1,130 (94.6%) had a pelvic mass on MRI with a reference standard (surgery, 768 [67.9%]; 2-year follow-up, 362 [32.1%]) and a total of 203 patients (18.0%) had at least 1 malignant adnexal or non-adnexal pelvic mass. 

Each patient underwent a routine pelvic MRI examination, including morphological sequences and functional sequences. The patients’ medical records were then reviewed, and gynecological symptoms and ultrasonographic findings were recorded. The quality of the ultrasonography report was recorded using widely used standardized criteria. Additionally, levels of CA 125 were recorded, if available. 

Both an experienced radiologist and a junior radiologist read the MRI scans prospectively and independently, and they were unmasked to clinical and sonographic findings. Then, another experienced reader who was masked to clinical and sonographic findings read the MRI retrospectively. The readers characterized each mass according to a standardized lexicon and assigned a score, and if there was no adnexal mass or if the original of a pelvic mass was non-adnexal, the readers were asked to assign a score of 1 and rate the mass as either suspicious or nonsuspicious for malignancy. 

In regard to the O-RADS MRI scoring system, a score of 1 to 3 was identified as no mass or benign and a score between 4 and 5 was deemed high risk. No invasive cancer was assigned a score of 2. 

The area under the receiver operating characteristic curve was 0.961 (95% CI, 0.948-0.971) among experienced readers, with a sensitivity of 0.93 (95% CI, 0.89-0.96; 189 of 203 patients) and a specificity of 0.91 (95% CI, 0.89-0.93; 848 of 927 patients). There was good interrater agreement among both experiences and junior readers (κ = 0.784; 95% CI, 0.743-0.824). Of the 580 women (51.3%) with a mass on MRI and no specific gynecological symptoms, 362 (62.4%) underwent surgery. Of them, 244 (67.4%) had benign lesions and a score of 3 or less.

The MRI score correctly reclassified the mass origin as non-adnexal with a sensitivity of 0.99 (95% CI, 0.98-0.99; 1,360 of 1,372 patients) and a specificity of 0.78 (95% CI, 0.71-0.85; 102 of 130 patients). 

“Correctly classifying an adnexal mass as benign has positive consequences, including the potential to reduce overtreatment by unnecessary or over-extensive surgery, to allow consideration of minimally invasive or fertility-preserving surgery, and to improve patient information regarding the risk of ovarian reserve alteration after surgery,” the authors wrote. 

According to the study, between 18% and 31% of adnexal masses remain indeterminate following ultrasonography using International Ovarian Tumor Analysis (IOTA) Simple Rules or other ultrasonography scoring systems. The utilization of MRI tool could potentially reduce unnecessary or over-extensive surgery and meet a clinical need. 


1. Thomassin-Naggara I, Poncelet E, Jalaguier-Coudray A, et al. Ovarian-Adnexal Reporting Data System Magnetic Resonance Imaging (O-RADS MRI) Score for Risk Stratification of Sonographically Indeterminate Adnexal Masses. JAMA Network Open. doi:10.1001/jamanetworkopen.2019.19896.

2. MRI tool can diagnose difficult cases of ovarian cancer [news release]. Imperial College, London. Published January 30, 2020. Accessed January 31, 2020.

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