PMC8769393_01
(A-C) CT scans on admission reveal diffuse subarachnoid hemorrhage with the predominant amount of clotting in the right cerebellopontine cistern. (D and E) The 3D DSA of the right VA reveals two aneurysms, a right VA dissecting aneurysm with irregular shape and a round fusiform aneurysm on the lateral medullary segment of the right PICA, which originated just proximal to the VA aneurysm; (D) anteroposterior view; (E) lateral view. PICA: posterior inferior cerebellar artery, VA: vertebral artery.
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F1
She complained of severe headache again 1 day prior to referral, and a CT scan performed at the same clinic revealed SAH (Fig. 1A-1C). CTA and vertebral artery (VA) angiography revealed two cerebral aneurysms, a large irregular and pearl-and-string-shaped dissecting aneurysm (maximum diameter, 16.6 mm) of the right VA and a small fusiform aneurysm (maximum diameter, 6.2 mm) on the lateral medullary segment of the right PICA (1.4 mm diameter), which originated just proximal to the right VA aneurysm (Fig. 1D and 1E). The CT scan from the clinic revealed a diffuse distribution of SAH around cisternal spaces, except for predominant clotting in the right cerebellopontine cistern (Fig. 1A).
(A-D): A and C (subtracted) and B and D (non-subtracted) angiograms show the anteroposterior view (A and B) and the RAO view (C and D) of the right VA, performed just after the stent-assisted coiling of the right VA aneurysm. Black arrows indicate the proximal and distal markers of the stent. (E) and (F) show the arterial and venous phases, respectively, of the RAO view 6 weeks later. Although the aneurysmal size of the right PICA was not changed, the stagnation of contrast medium in the aneurysm persisted to the venous phase. (G and H) The RAO view of the right VA angiogram 11 (G) and 17 (H) months after the stent jailing, showing the decrease (G) and the disappearance (H) of the PICA aneurysm. The right VA is gradually straightened and the angle between the right PICA and right VA is slightly sharpened from (C) and (D) to (G) and (H). PICA: posterior inferior cerebellar artery, RAO: right anterior oblique, VA: vertebral artery.
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F2
Three target detachable coils (Stryker, Fremont, CA, USA) were inserted into the aneurysm, preserving the origin of the anterior spinal artery (Fig. 2A-2D). Although no remarkable change of the aneurysmal size of right PICA was seen until 3 months after the operation, the stagnation of contrast medium in the PICA aneurysm persisted to the venous phase 6 weeks (Fig. 2E and 2F) and 3 months after the operation. Angiograms performed 11 and 17 months later revealed moderate shrinkage (Fig. 2G) and complete disappearance of the PICA aneurysm (Fig. 2H), respectively. The angulation of right VA was gradually straightened, and the angle of the right PICA against the right VA slightly sharpened following the stent placement (Fig. 2C-2H).
(A) The TOF-MRA image 3 weeks after the stent jailing indicates the small and round fusiform aneurysm (large arrow) of the PICA. (B) The TOF-MRA image 39 months after stent jailing indicates aneurysmal shrinkage of the PICA. (C-E) MRI performed 39 months after stent jailing. The comparison of images of TOF-MRA (C), heavily T2-weighted imaging (D), and MR-VWI (E) indicates no thrombus formation or thickened wall of the aneurysm sac (small arrows). MR-VWI: magnetic resonance vessel wall imaging, PICA: posterior inferior cerebellar artery, TOF-MRA: time-of-flight MRA.
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F3
Time-of-flight MRA (TOF-MRA) images obtained at 3 weeks (Fig. 3A) and 39 months (Fig. 3B) following stent jailing revealed aneurysmal shrinkage. TOF-MRA (Fig. 3C), heavily T2-weighted imaging (Fig. 3D), and contrast-enhanced magnetic resonance vessel wall imaging (MR-VWI) (Fig. 3E) of the same lateral medullary segment of the right PICA. The TOF-MRA represents the inside of the artery, the heavily T2-weighted imaging indicates the outside of the artery, and MR-VWI shows the wall of the artery, which indicated no thickness or thrombosis of the wall of this segment.