Neonatal ovarian cysts: management with reference to magnetic resonance imaging.

Objective: Ultrasound (US) has been used as a tool to determine the indication for surgery for neonatal ovarian cysts. The purpose of this study was to investigate whether magnetic resonance imaging (MRI) contributes to optimal management.

Methods: Between 1993 and 2001, US and MRI studies were simultaneously performed on 13 consecutive infants younger than 2 months of age with ovarian cysts. The US Patterns were classified as complex or simple. Signal intensity (SI) of the cysts on MRI was compared with that of the liver on T1-weighted images (T1WI) and with urine on T2-weighted images (T2WI). We assumed that high SI on T1WI and iso or low SI on T2WI indicated complications.

Results: There were 10 complex and three simple cysts on US. Of the 10 complex cysts, two had no complications at surgery or resolved spontaneously. These two cysts showed low SI on T1WI. Eight complex cysts showed high SI on T1WI and all were haemorrhagic. The US diagnosis corresponded to the MRI findings in three simple cysts. The sensitivity of US for haemorrhage was 80%, and that of MRI was 100%.

Conclusions: We found that MRI was a more reliable diagnostic modality than US for diagnosing neonatal ovarian cysts.