PMC7656028_01
T1-weighted MRI sequence performed before the endoscopic third ventriculostomy. On this MRI, performed 20 years ago and for this reason of suboptimal quality, we identified the presence of a dilatation of the supratentorial compartment of the ventricular system and the presence of a membranous aqueductal stenosis.
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F1
Due to frequent episodes of headache, a 30-year-old female underwent neuroradiological investigations that documented the presence of an aqueductal stenosis with triventricular hydrocephalus and transependymal transudation [Figure 1].
Preoperative MRI. The preoperative MRI demonstrated a biventricular hydrocephalus with sings of transependymal transudation (a). The coronal scans documented that the right lateral ventricle was more dilated than the left one (b) and both FM were occluded (c), with an apparent enlargement of the left FM aditus (yellow arrow). In the sagittal plane, the stoma was not identifiable, while it was possible to objectify an aqueductal stenosis due to the presence of septa inside it (d).
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F2
The MRI showed a dilatation of the lateral ventricles with slight deviation of the septum and slit third ventricle, indicating an obstruction of both FM [Figure 2].
Intraoperative findings. Performing a left-sided approach, we observed that a thin fibrous membrane occluded the homolateral FM (a). We enlarged the left FM (b) and entered in a slit third ventricle (c). We documented the patency of the endoscopic third ventriculostomy (d). We also perforated the septum (e) and, through the septostomy, we evaluated the right FM (f).
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F3
We also fenestrated the septum and, through the septostomy, evaluated the contralateral FM, which was also occluded by a fibrous membrane [Figure 3].
Postoperative MRI. The postoperative MRI demonstrated the resolution of the dilatation of both lateral ventricles and of the transependymal transudation (a). We could identify the signs of our left-sided foraminoplasty (b), septostomy (c), and endoscopic third ventriculostomy (d).
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F4
After surgery, the symptoms improved and the early postoperative MRI showed the resolution of the biventricular hydrocephalus and the patency of septostomy, foraminoplasty, and ETV [Figure 4].
Volumetric analysis. To objectify the reduction of the ventricular system dilatation, we segmented the preoperative (a-c) and postoperative MRI (d-f). Comparing axial (a,d), coronal (b,e), and sagittal (c,f) images, we identified a reduction of the biplanar dimensions of the ventricular system. This reduction was confirmed by the analysis of the preoperative (191.8 cm3) and postoperative (135.9 cm3) volumes.
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F5
We obtained a preoperative ventricular system's volume of 191.8 cm3, while in the postoperative MRI, the value was reduced to 135.9 cm3 [Figure 5].