Accuracy of pelvic ultrasound in preoperative evaluation of uterine myomas: A prospective cohort study

The purpose of this study was to evaluate the accuracy of transvaginal and transabdominal sonography in myoma diagnosis, mapping and measurement. This was a prospective study of consecutive premenopausal women who underwent myomectomy (MY) or hysterectomy (HY) for benign pathology at the Department of Gynecology of Sapienza University of Rome between September 2015 and March 2016. Myomas were exactly mapped by ultrasonography (US) the day before surgery by two expert sonographers. The number, localisation and size of uterine myomas were compared with intraoperative visualisation in case of MY and with anatomopathological (AP) findings in case of HY. We including 45 patients: 24 underwent MY and 21 HY. The analysis showed a significant difference between myomas number at US and at AP, with a concordance in 17 of 45 patients (38%), in all other cases the myomas number was statistically higher. In 76.5% of these was exactly identified myomas number at US when there were 1 myoma, in 12% when the number of myomas was equal to 2 or 3 and the concordance rate decreases with increasing myomas number. Stratified analysis shows that we identify by US myomas with size between 10 and 25 mm, underestimate their size when they are greater than 26 mm and we miss those under 10 mm especially if associated with very large myomas (>70 mm).US detection failure was significant for myomas with maximum ranged diameter of 31–50 mm (p 0.042) , 51–70 mm (p 0.036) and > 70 mm (p 0.021), with a medium size difference respectively of 12,5 mm, 18,7 mm and 28,1 mm. The mapping of not detected myomas at US was: 63% for intramural posterior myomas, 55% for subserous anterior myomas, 51% for intramural anterior myoma, 40% for subserous posterior myomas and 7% for submucosal anterior myomas. There were no difference between two groups (MY vs HY). US is efficient in detecting myoma presence, but its capacity for exact myoma count and mapping falls for intramural side.