Patients selection
This prospective cross-sectional study was approved by our institutional review board (IRB no. 17100016). Written informed consent was obtained from each patient for participation and publication after receiving information about the details of the study. This trial was registered in the US National library of medicine with NCT03175991 number in clinical trial. The sample size was calculated using the Open Epi software program, version 23.1.
This study was carried out between March 2017 and August 2018. One hundred sixteen women were studied in our center based on suspicion of having ovarian lesion on clinical examination, accidentally discovered ovarian lesion on US examination or computed tomography, or having high serum level of CA-125.
Method
After fulfilling the clinical data (including the age and menopausal status), all patient’s pelvises were examined by Prosound Alpha 7 ultrasound machine (Hitachi Aloka Medical America, Inc., Germany). We used transabdominal, transvaginal, or both approaches.
Gray-scale sonographic and Doppler data analysis
Each ovarian lesion was evaluated morphologically according to the following parameters: tumor volume more or less than 10 cm3, solid component (not present, hyperechoic, non-hyperechoic), cystic component (not present, anechoic, echogenic), papillary projection, septal thickness (not present, thin < 3 mm, thick ≥ 3 mm), and wall thickness (not identified, thin < 3 mm, thick ≥ 3 mm).
After morphological evaluation, color flow Doppler was activated. It was stated as having flow when the flow was central, and it was considered to have no flow when no signal could be detected or if the blood flow was peripheral. Once a central vessel was identified by the color Doppler US, the spectral Doppler parameters as resistive index (RI) and pulsatility index (PI) were automatically calculated. The lowest RI and PI were used for analysis, if there were more than one vessel within the lesion [9].
The following diagnostic algorithm was used:
Any mass has the following criteria: volume ≥ 10 cm3, non-hyperechoic solid component, papillary projection, septal thickness ≥ 3 mm, wall thickness ≥ 3 mm, mass with central blood flow and RI < 0.6, and PI < 1.6 were categorized as suspicious for malignancy [10].
The gold standard test for the benign lesions (as hemorrhagic cysts (Fig. 1)) was spontaneous resolution after 6–8 weeks of sonographic follow-up (n = 88). However, the gold standard test was a histopathological examination of all the malignant ovarian lesions (n = 53) and 15 benign ovarian lesions which have not typical signs of benignity. Tumors were classified according to the FIGO criteria [13] and staged according to WHO criteria [14].
Statistical analysis
Data was collected and analyzed using SPSS (Statistical Package for the Social Science, version 20, IBM, and Armonk, New York). Continuous data were expressed in the form of mean ± SD or median (range), while nominal data were expressed in the form of frequency (percentage). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio, and negative likelihood ratio for each sonographic and Doppler parameter were calculated using the ROC curve. Chi-square test was used to compare the nominal data of different groups in the study, while the student t test was used to compare the mean of different two groups and ANOVA tests for more than two groups. Multivariate regression analysis for predictor of ovarian malignancy was calculated; p value was significant if < 0.05.