Prenatal Diagnosis and Outcome of Infratentorial Fluid Collections

Background: Infratentorial fluid collections encompass a wide spectrum of different entities, ranging from normal variants to severe anomalies. They may have a similar anatomic as well as sonographic appearance, and diagnostic errors with significant implications for counseling and management have been described. New advances in prenatal imaging have allowed more detailed evaluation of infratentorial region as well as correct diagnosis for adequate counseling of the parents. Aim of the Work: The study aimed to evaluate the values of fetal MRI and US in the diagnosis of infratentorial fluid collections comparing their end results with the post delivery scans. Patients and Methods: This study involved 90 pregnant females. Gestational Age (GA) ranged from 17th to 28th Weeks Gestation (WG) with a mean of 24th WG. Study has been carried out between March 2011 and May 2014. Pregnant females were referred from obstetric outpatient clinics and Feto-Maternal Unit in Kasr Al-Aini Hospital to Radiology Department Female Imaging Unit. Preliminary US examination was done in all cases using 3.5-5MHz curvilinear 2D trans-ducer, including multiplanar assessment was performed. Fetal MRI was performed in all cases using 1.5 T MR magnet. Prenatal results were correlated with postnatal (MRI or CT) imaging. This study was approved by the hospital research ethics committee. All pregnant females were counseled and signed a consent form. Results: During the study period, 90 pregnant females were examined, at a mean 24 WG (range, 17-28), 45/90 (50%) fetuses were suspected to have infratentorial fluid collections on prenatal US, however, fetal MRI diagnosed 62/90 fetuses (68%). Postnatal imaging confirmed 60/90 cases (66%) with infratentorial fluid collections. The results of our study showed superior diagnostic performance of fetal MRI compared to prenatal US in diagnosis of infratentorial fluid collections.