## 2 Materials and Methods  
### Patients  
This was a prospective single center study (Obstetrics and Gynecology Hospital \"Cuza Voda\" Iasi, Romania) performed between 2017 and 2019, which included 230 patients, the age range being 17 to 74 years. Patient selection criteria included hypogastric pain, infertility, metorrhugia, dysmenorrhea and dyspareunia.  
At the outset of the medical investigations, the women had a clinical and paralclinical diagnosis of ovarian masses in the private sector through detailed history and using transvaginal and transabdominal ultrasonography. Following that, the cases with high suspicion of benign tumors were sent to our hospital for evaluation and surgery. In order to minimize bias, all the patients were evaluated by experienced specialists using the same ultrasound machine, the Voluson E8 equipped with IOTA ADNEX(tm) software.  
Each patient signed a written informed consent. The informed consent was approved by the Commission for Medical Ethics of the University of Medicine [PERSON], Iasi (790/2017).  
We collected all data pertaining to the patients that approached our clinic for ovarian masses. We observed the following morphological aspects:  
1. [noitemsep]
2. Laterality (unilateral or bilateral);
3. Maximum diameter;
4. Echogenicity;
5. Wall thickness;
6. Cystic content;
7. Solid areas;
8. Spotations;
9. Solid papillary projections;
10. The presence of ascites;
11. The Doppler evaluation [2; 12].  
From our hospital's electronic database, we retrieved data concerning the values of CA 125, the type of surgery and the histopathological results after the surgery.  
We applied the IOTA ADNEX model protocol.  
The preoperative classification system of adnexal masses is composed of 5 specific features for benign tumors (B-rules) and 5 specific features for malignant tumors (M-rules). These rules are useful in diagnosing patients with at least one persistent adnexal mass before surgical treatment.  
Rules for predicting a benign tumor \(\rightarrow\) B-rules:  
* B1: unilocular cyst;
* B2: presence of solid components (largest diameter <7 mm);
* B3: presence of acoustic shadowing;
* B4: smooth multilocular tumor with the largest diameter <100 mm;
* B5: no blood flow (color score 1).  
Rules for predicting a malignant tumor \(\rightarrow\) M-rules:  
* M1: irregular solid tumor;
* M2: presence of ascites;
* M3: at least four papillary structures present;
* M4: irregular, multilocular, solid tumor with the largest diameter > = 100 mm;
* M5: intensive blood flow (color score 4).  
If one or more B-rules were present in the absence of M-rules, the ovarian masses were classified as benign. However, if one or more M-rules were present in the absence of B-rules, the mass was classified as malignant [2].  
The ADNEX model is available at [[http://www.iotagroup.org/adnexmodel/](http://www.iotagroup.org/adnexmodel/)]([http://www.iotagroup.org/adnexmodel/](http://www.iotagroup.org/adnexmodel/)) (accessed on 17 June 2021) (Figure 1).  
The IOTA ADNEX model is able to estimate the probability of an adnexal tumor of being benign, borderline or malignant [11; 19].  
In the case the mass is suspected to be malignant (elevated CA-125, ascites, fixed pelvic mass, abdominal metastasis and/or increased IOTA ADNEX risk of malignancy), the patient should be directed to a gynecological oncology center.  
The golden standard remains the histological diagnosis of the surgically removed tumor.