PMC9168298_01
(a) Diffusion-weighted MRI showing no lesion in the medulla oblongata including the hypoglossal nerve nucleus. (b) T2-CUBE MRI showing false lumen of ICAD compressing the hypoglossal nerve tube, and the perineural space in the left hypoglossal canal is dilated (arrow). (c) T1-weighted MRI with contrast-enhancement showing dissected false cavity (arrowhead) compressing the distal side of the hypoglossal canal (arrow). (d) MRA showing a left ICAD with a false lumen (arrow). (e) Angiography showing a left ICAD (arrow). (f) Cone-beam CT showing that the false lumen (arrowhead) is protruding to the direction of the hypoglossal canal (arrow). Direct compression is thought to be causing hypoglossal nerve palsy.
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F1
Diffusion-weighted magnetic resonance images (MRI) did not demonstrate any lesions that could cause left hypoglossal nerve palsy [Figure 1a]. T2-CUBE MRI demonstrated a false lumen of ICAD that compressed the outlet portion of the hypoglossal nerve tube and dilation of the perineural space in the hypoglossal canal [Figure 1b]. The false lumen of ICAD was adjacent to the hypoglossal canal at its distal side and protruded toward the hypoglossal neural tube. These findings indicated that direct compression by the false lumen was the cause of hypoglossal nerve palsy [Figure 1c]. MR angiography (MRA) showed dissection of the left ICA accompanied with a false lumen [Figure 1d]. Cerebral angiography performed on the 8th day showed an ICAD consistent with the findings on MRI and MRA [Figure 1e]. Cone-beam computed tomography (CBCT) showed protrusion of the false lumen to the hypoglossal canal [Figure 1f].
(a) Post-CAS angiography demonstrating dilatation of the true lumen of ICA. (b) Congestion of contrast medium in the false lumen is observed immediately after stenting.
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F2
Angiography immediately after stenting showed dilatation of the true lumen and congestion of contrast medium in the false lumen [Figure 2].
Cerebral angiography performed at month 6 demonstrating sufficient dilatation of ICA and absence of the false lumen.
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F3
Cerebral angiography performed at month 6 showed well-dilated ICA and disappearance of false lumen [Figure 3].