Fig. 6
From: Non-visualisation of cavum septi pellucidi: implication in prenatal diagnosis?
Alobar HPE. a Coronal ultrasound at 21 weeks’ gestation demonstrates apparent fusion of thalami (arrow), and overlying supratentorial CSF-filled cavity without discernible cortex, although significant near-field reverberation artefact was present. Sonographic considerations included alobar HPE and hydranencephaly and patient chose to continue with pregnancy. b Coronal T2-weighted MRI at 31 weeks gestation confirms the presence of fused thalami and absent falx. c Axial T2-weighted MRI demonstrates absence of CSP and non-cleavage of the hemispheres. The falx and interhemispheric fissure are completely absent. The single crescent-shaped forebrain ventricle (arrow), monoventricle (“Amadeus ventricle”), openly communicates with a large dorsal cyst (asterisk). d Sagittal T2-weighted MRI demonstrates communication of the monoventricle (arrow) with a large dorsal cyst (asterisk)