Title : The brainstem beyond the “Blind Spot” of prenatal diagnosis: MRI observation series
Abstract:
Purpose: To analyze the contribution of magnetic resonance imaging (MRI) to the prenatal diagnosis of anomalies of brainstem structures using the example of describing our own rare clinical observations and comparing the results of MRI with the changes identified during a previous Ultrasound.
Materials and methods: A retrospective analysis was conducted of 5 cases of various brain stem anomalies identified by fetal MRI (gestational age range 19–29 weeks) on 1.5T (Achieva) and 3T (Ingenia) Philips scanners at the International Tomography Center of the SB RAS, on a 3T (GE HealthCare) at the “Scandinavia” clinic.
Results: In all 7 cases, MRI revealed a brainstem malformation: dysplasia of the diencephalic-mesencephalic junction (1), pontocerebellar hypoplasia (1), Joubert syndrome (2), brainstem kinking (2), and brainstem disconnection (1). Most of the anomalies were not detected by Ultrasound or was interpreted as a cerebellar abnormality (5/7). In addition, MRI revealed concomitant pathologies: cerebellar hypogenesis (6/7), ventriculomegaly (5/7), anomalies of cortical development (3/7), microcephaly (1/7), the corpus callosum anomaly (4/7), cleft lip and palate (1/7). We represent the embryogenetic principles of the concomitant development of the brainstem structures and the posterior cranial fossa anomalies. Presented US and MR imaging data of all 7 cases of rare brain anomalies provide a practical benefits for radiologists, focusing their attention on the difficulties of diagnosing brain stem structures using only US.
Conclusions: Ultrasound has limitations in imaging the brainstem in the 2nd trimester, in most cases identifying only an associated cerebellar abnormality. MRI provides the necessary quality of visualization for detecting anomalies of stem structures and identifying the entire spectrum of associated intrauterine developmental defects, which helps to timely determine the necessary tactics and suspect a genetic syndrome.
Audience Take Away:
- Presented US and MR imaging data of rare brain anomalies provide a practical benefits for radiologists, focusing their attention on the difficulties of diagnosing brainstem structures using only US.
- The audience will be able to use what they learn in the practice of prenatal diagnosis of brain malformations, increasing their accuracy and specificity in detecting brain stem abnormalities.
- Considering the critical importance of early detection of abnormalities of the brainstem, the presented information will help to avoid mistakes in determining pregnancy management.
- We show practical useful diagnostic pitfalls and life hacks of MRI diagnosis of brainstem anomalies.
