PMC9168332_01
Preoperative MRI. MRI SPGR (left side) and T2 drive (right side) images confirmed that the left vertebral artery (black arrow) and anterior inferior cerebellar artery (red arrow) were close to the facial nerve (yellow arrow heads), but the detailed relationship with REZ of facial nerve was difficult to understand. a: left upper, b: right upper, c: left lower, d: rtght lower.
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F1
MRI T2 drive and SPGR images confirmed that the left vertebral artery (VA) and anterior inferior cerebellar artery (AICA) were close to the facial nerve, but the detailed relationship with the REZ of the facial nerve was difficult to understand [Figure 1].
Depiction of the facial nerve by MRI diffusion tensor image (DTI). We have created 3D images of the facial nerve and brainstem (d: coronal; e: sagittal; and f: axial view) by extracting RExZ and AS (green) and RDP and CP (yellow) of the facial nerve with reference to DTI( a, coronal; b: saggital, c: axial view, blue line: diffusion tensor image) d, e, f: purple: brainstem. g; Preoperative image: the left vertebral artery and anterior inferior cerebellar artery compressed REZ of the left facial nerve (green).
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F2
MRA and DTI fusion images revealed compressed left facial nerve at the portion of AS, secondary to tortuous and elongated VA, and AICA [Figure 2].
Intraoperative view. REZ (yellow arrow heads) of facial nerve was decompressed by transposition of the left vertebral artery (black arrows) and interposition of anterior inferior cerebellar artery (red arrows).
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F3
AICA was performed [Figure 3]. After operation, the spasm disappeared immediately.
Perioperative fusion images. Brainstem (purple), the AS and RExP parts of the facial nerve called REZ (green), other parts of the facial nerve (yellow) and MRA (preoperative [red] and postoperative [blue] vertebrobasilar system). (a) Postoperative image: vascular compression on REZ has been released. (b) Fusion image of pre- and postoperative examination could allow us to evaluate the extent of decompression easily. Preoperative vascular image (translucent blue), postoperative vascular image (red), and REZ of facial nerve (green).
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F4
We could recognize the decompressed facial nerve using the created images in the manner we described [Figures 4a and 4b].