Real-Life Diagnostic Accuracy of MRI in Prenatal Diagnosis

Figure 4

Arachnoid cyst associated with persistence of Liliequist membrane. Gestational age: 36 weeks and 2 days. (a) Sagittal SSFSE T2. Large-sized arachnoid cyst (solid white arrow) anterior to the mesencephalon extending into the prepontine cistern and suprasellar region is shown. The cyst produces a slight mass effect of the protuberance (empty white arrowhead) and an important mass effect on the mesencephalon (solid white arrowhead), hypothalamic region (empty black arrowhead), mammillary bodies (solid black arrow), the floor of the third ventricle (curved white arrow), and optic chiasm (solid black arrowhead). (b) Diffusion tensor with axial tractography image. The cyst (solid white arrow) extends towards the interpeduncular cistern of the mesencephalon and displaces the corticospinal tracts in a posterolateral direction (empty white arrows). Fetal MRI provides additional information because the real extent of the lesion is better evaluated than with ultrasound.

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