PMC10370514_01
Initial MRI showing a large aneurysm (arrows) of the right ICA in the cavernous sinus with findings suggestive of partial thrombosis. (A) T1-weighted image, (B) T2-weighted image, and (C) time-of-flight-MRA. ICA: internal carotid artery
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F1
Head MRI showed a large aneurysm (22 mm) in the cavernous sinus of the right ICA with findings suggestive of partial thrombosis (Fig. 1A-1C).
Pretreatment right internal carotid angiography showing a large aneurysm of the right ICA in the cavernous sinus with a PTAv bifurcated from the aneurysm proximal neck. (A) Anterior-posterior view, (B) lateral view, and (C) 3D rotation angiography. ICA: internal carotid artery; PTAv: primitive trigeminal artery variant
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F2
Cerebral angiography showed a large aneurysm in the cavernous sinus of the right ICA with a PTAv branch proximal neck to the aneurysm (Fig. 2A-2C).
BOT images. (A) Live image of BOT showing balloon (arrow) dilation in the ICA including PTAv. (B) Pan-aortography early venous phase showing left-right differences. (C) Right vertebral angiography under BOT: Blood flow from the right VA to the BA and retrograde right AICA can be seen. AICA: anterior inferior cerebellar artery; BA: basilar artery; BOT: balloon occlusion test; ICA: internal carotid artery; PTAv: primitive trigeminal artery variant; VA: vertebral artery
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F3
PTAv proximal to the aneurysm, and evaluated ischemic tolerance (Fig. 3A). Pan-aortography did not show any left-right difference in the early venous phase (Fig. 3B). Right vertebral artery (VA) angiography showed that the right ICA was well perfused through the posterior communicating artery (PcomA), while the basilar artery (BA) was also perfused anterogradely from the right VA (Fig. 3C).
Images from the coil embolization. (A) Superselective angiogram of the PTAv showing blood flow in the right AICA region. (B) PTAv embolization with coils (arrow: PTAv embolization site, arrowheads: microcatheter). (C) Live image of parent artery occlusion of the right ICA with coils. (D) Left internal carotid angiography after occlusion showing good right ICA territory blood flow via the anterior communicating artery. (E) Right VA angiography after occlusion showing retrograde blood flow in the AICA territory (or region) (arrow: AICA region perfused with leptomeningeal anastomosis). AICA: anterior inferior cerebellar artery; ICA: internal carotid artery; PTAv: primitive trigeminal artery variant; VA: vertebral artery
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F4
A LANTERN microcatheter (Medicos Hirata, Tokyo, Japan) was then guided to the aneurysmal origin in the ICA and an Axium Prime 3D ES 1 mm x 2 cm coil (Medtronic, Minneapolis, MN, USA) was inserted through the SL10 to occlude the PTAv (Fig. 4A and 4B). Subsequently, a total of eight coils were tightly placed from the aneurysm-proximal area to the horizontal portion (Fig. 4C). After embolization, right internal carotid angiography showed no aneurysm and left internal carotid angiography demonstrated no differences in the early venous phase (Fig. 4D). Right vertebral arteriography showed that the territory of the right AICA (or right AICA region) was retrogradely filled by leptomeningeal anastomosis from superior cerebellar artery (SCA) and posterior inferior cerebellar artery (PICA) (Fig. 4E).
MRI on the day after surgery (A and B: diffusion-weighted image) showing no high-intensity signal and 6 months after surgery (C: T2-weighted image and D: time-of-flight-MRA maximum intensity projection) showing the aneurysm had almost disappeared.
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F5
The next day, diffusion-weighted imaging was negative for ischemic complications and the FLAIR mode showed signal changes inside the aneurysm (Fig. 5A and 5B). Six months later, MRI showed that the aneurysm had almost disappeared and diplopia was in remission (Fig. 5C and 5D).