Long Term Outcomes of Fetal Posterior Fossa Abnormalities Diagnosed with Fetal MRI.

OBJECTIVE: The diagnosis of posterior fossa abnormalities (PFA) in the intrauterine period; and pregnancy outcomes are still controversial. PFA is generally referred to as maternal-fetal medicine specialists. The primary purpose of PFA diagnosis is to screen for other accompanying abnormalities, provide prognostic information to families, and discuss the termination option.

MATERIAL AND METHODS: This retrospective study was conducted with patients diagnosed with PFA between January 2013 and September 2020 in the tertiary Perinatology Clinic. All patients were routinely performed second-trimester ultrasound screening, and the definitive diagnosis was made by fetal MRI in the presence of a suspected anomaly.

RESULTS: Between 2013 and 2020, 164 fetal MRIs were performed for fetal abnormalities, and 22 fetuses were diagnosed with a PFA on fetal MRI. Considering the fetal MRI indications of the cases, four patients (18%) were diagnosed with Mega Cisterna Magna (MSM), Two patients were diagnosed with rhomboencephalosynapsis, thirteen patients were diagnosed with Vermian Hypoplasia-Dandy-Walker variant. In the remaining two patients, those with neural tube defects and lumbosacral NTD are still alive. However, iniencephaly was detected in the other patient and died in the postnatal period.

CONCLUSION: Diagnosis of PFA abnormalities is complex, and it is a condition that cannot be predicted clearly which patients will have a good prognosis and which will have a bad prognosis. The prognosis is not affected by maternal and fetal factors and allows the recognition of additional accompanying abnormalities. Fetal MRI is an imaging method that can provide retrospective examination and research, especially in pregnancies with poor prognoses.