Background: The clinical diagnosis of ovarian torsion is challenging and findings on pelvic sonography can be pivotal in making the correct diagnosis.
Objective: To determine the sonographic characteristics in children of surgically and pathologically proven ovarian torsion.
Material and methods: We performed a retrospective review of the sonograms and medical records of 41 patients with surgically and pathologically proven ovarian torsion at a pediatric hospital between 1994 and 2005. All sonograms were reviewed retrospectively by two pediatric radiologists with attention to the size, echotexture, location, presence of peripheral round cysts, and evidence of flow on Doppler sonography within the torsed ovary. The amount of free pelvic fluid was also recorded.
Results: The most common sonographic finding of ovarian torsion was an enlarged ovary/adnexal mass. All torsed adnexa were larger than the normal contralateral ovary, with the median volume 12 times that of the normal contralateral side. The majority (61%, n = 25) of the torsions occurred on the right. Color flow, either venous or arterial, was present in 62% (n = 21/34) of the torsed ovaries for which flow on Doppler sonography was documented. In 63% of the torsed ovaries (n = 26), the torsed adnexa appeared heterogeneous. Ovarian or para-ovarian pathology that may have acted as a potential lead point was present in 55% (n = 24) of torsed ovaries. The volume ratio of the torsed to normal ovary can predict the presence of an ovarian mass within the torsed ovary. In 70% of torsed ovaries with a volume ratio greater than 20, an ovarian mass was present, and in approximately 90% of those with a volume ratio less than 20, an internal mass was absent.
Conclusion: An enlarged heterogeneous appearing ovary is the most common finding in ovarian torsion. The presence or absence of flow by Doppler sonography is not helpful in the diagnosis. The volume ratio of the torsed to the normal ovary can predict the presence of an internal mass within the torsed adnexa.