A new sonomorphologic scoring system (Mainz Score) for the assessment of ovarian tumors using transvaginal ultrasonography. Part I: A comparison between the scoring-system and the assessment by an experienced sonographer.

OBJECTIVE

The problem of an accurate sonographic assessment of ovarian tumor status has not yet been solved. To what extent can the preoperative assessment of adnexal tumors be improved on the basis of a maximum number of sonographic tumor parameters included in the newly developed sonomorphologic Mainz Score?

MATERIALS AND METHODS

In a prospective study 314 premenopausal patients with adnexal tumor underwent a transvaginal sonographic examination performed by an experienced sonographer. In parallel to the sonographic examination a new score including 10 different sonographic parameters was used to predict adnexal tumor status: 1. Total tumor structure, 2. tumor border, 3. wall thickness, 4. inner echos in cystic component, 5. septa, 6. shape of echo complex or of the completely solid tumor, 7. echogenicity of the echo complex or of the completely solid tumor, 8. acuostic phenomena behind tumor, 9. ascites, 10. detection of liver metastases/peritoneal carcinosis Depending on the respective degree of expression, the individual characteristics were rated on a scale from 0 to 2. The total score obtained following addition of the points recorded for each parameters served to confirm the validity of the sonographic tumor status assessment. The first sonographer assessed the tumor status based on his experience and in the knowledge of all clinical parameters. The second sonographer evaluated the tumor status based on the score. All preoperative ultrasonographic findings were compared with the postoperative histologic analysis.

RESULTS

A maximum number of 20 points may be obtained using the Mainz Score. Tumors with a total score of below 9 were rated as benign and those with a score of above 9 as malignant. This resulted in a sensitivity of 96.4%, a specificity of 80.7%, a positive predictive value of 47.4%, and a negative predictive value of 99.6%. The predictive value of the scoring-system was diminished by the presence of 30 false-positive cases, which were identified as inflammatory conglomerate tumors, teratomas, endometrial cysts, cystadenomas and hemorrhagic cysts. The experienced sonographer assessed 233 cases as benign and 24 cases as malignant. The findings were confirmed by the histological examination in 252 of 257 cases. No conclusive prediction of tumor status could be made in 57 tumors. However, the application of the Mainz Score enabled an accurate prediction of the tumor status in 44 of the 57 cases. With the exception of septal thickness all assessment criteria of the score showed a statistically significant correlation between the assigned score and the histologic findings, (p < 0.05).

CONCLUSIONS

The use of the Mainz Score enables even less experienced sonographers to assess the status of premenopausal adnexal tumors with a high degree of accuracy. The score provides the experienced sonographer with a refined and improved method for the prediction of tumor status, especially in the presence of not readily assessable findings.