PMC9062920_01
(a-d) Initial MRI (a: T2-weighted image, b: T1-weighted volume isotropic turbo spin-echo acquisition, c: sagittal reconstruction image of MRA, and d: MRA). The basilar artery was dilated and the top of the artery extended upward (b and d). The right posterior cerebral artery extended the floor of the third ventricle upward but did not touch the fornix (c). The enlargement of the ventricles was not observed (a). (e-h) MRI 5 years later (the second examination); (e) T2-weighted image, (f) T1-weighted volume isotropic turbo spin-echo acquisition, (g: sagittal reconstruction image of MRA, h: MRA). The left internal carotid artery was asymptomatically occluded (h). The basilar artery and right posterior cerebral artery extended further upward and the floor of the third ventricle touched the fornix (f and g). The enlargement of the ventricles was not observed (e). (i-l) MRI 1 year and 7 months later (the third examination, just before ETV); (i) T2-weighted image, (j) fluid-attenuated inversion recovery image, (k) sagittal reconstruction image of MRA, and (l) T2 drive image. The bilateral ventricle and the third ventricle were enlarged (I and j). The right posterior cerebral artery extended further upward and touched the fornix while deformities of the midbrain and pons were also observed (k). The floor of the third ventricle was observed to be ballooning (l).
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F1
Magnetic resonance imaging (MRI) showed that the basilar artery was elongated, protruding upward, and compressing the third ventricle floor [Figure 1a-d]. Although he experienced no changes in clinical symptoms, 5 years later, MRI showed asymptomatic left internal carotid artery occlusion and further VBD elongation [Figure 1e-h] while SPECT showed no decrease in cerebral blood flow. MRI showed a significant dilation of both lateral ventricles, periventricular hyperintensity, and ballooning of the third ventricle [Figure 1i-l].
Images of the endoscopic third ventricle ventriculostomy. (a) The foramen of Monro was observed from the right ventricle, which was enlarged. (b) Consolidated images of endoscopic findings in the third ventricle. The floor of the third ventricle extended to the fornix due to the upward extension of the right posterior cerebral artery (white arrowhead). The mamillary body was stretched (white arrow). (c) The basilar artery (asterisk) was confirmed through the floor of the third ventricle. (d) The floor of the third ventricle was fenestrated to avoid injuring the basilar artery. (e) The vascular wall of the basilar artery (asterisk) had white sclerotic changes.
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F2
An insertion port was placed on the right frontal lobe toward the anterior horn of the right ventricle and a flexible endoscope was inserted [Figure 2a]. The posterior part of the third ventricle floor was stretched upward due to the extension of the right posterior cerebral artery [Figure 2b] and the third ventricle floor was seen to be ballooning while the tuber cinereum was thinning. Arterial pulsation was confirmed through the third ventricle floor [Figure 2c]. The tuber cinereum was fenestrated at the right posterior of the infundibular recess, avoiding the artery [Figure 2d]. The endoscope was inserted into the basal cistern through the fenestration at the tuber cinereum and the basilar artery adventitia was observed to be white from fibrotic change [Figure 2e].
Postoperative MRI showed that the ventricles were shrinking (a: T2-weighted image) and the floor of the third ventricle was fenestrated (b: T2 DRIVE image).
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F3
On postoperative day 7, MRI showed a decrease in dilatation of both lateral ventricles and the periventricular hyperintensity had also improved [Figure 3a]. In addition, the cerebrospinal flow void at the fenestration on the third ventricle floor was confirmed and the right posterior cerebral artery had returned to the anterior position [Figure 3b].