A case of internal trapping to a thrombosed giant rapidly growing aneurysm at the posterior cerebral artery

Abstract

We describe a case of internal trapping including the vasa vasorum for a thrombosed giant rapidly growing posterior cerebral artery aneurysm and performing a detailed analysis. A 48-year-old woman was followed up in our hospital for a thrombosed large posterior cerebral artery aneurysm located in the P2 segment. She initially presented after experiencing a sudden headache on two occasions. Head computed tomography and magnetic resonance imaging indicated a larger aneurysm than before. Digital subtraction angiography with balloon occlusion test was assessed, and internal trapping was sequentially conducted. We detected that the vasa vasorum originated from the posterior temporal artery. Therefore, we embolized the posterior temporal artery including the vasa vasorum using N-butyl-2-cyanoacrylate and Lipiodol. Next, the anterior temporal artery was embolized with N-butyl-2-cyanoacrylate and Lipiodol, posterior temporal artery P3 segment and the aneurysm and finally the proximal P2 segment were embolized with coils. Final vertebral and internal carotid angiography showed complete obliteration of the aneurysm. On the day after the procedure her paresis worsened and she developed left upper quadrantanopia, however was finally discharged with no hemiparesis. We reported a case of a rapidly growing thrombosed giant posterior cerebral artery aneurysm treated by parent artery occlusion including the vasa vasorum with detailed image analysis.

Keywords: parent artery occlusion; posterior cerebral aneurysm; thrombosed giant aneurysm; vasa vasorum.

Fig. 1

MRI and CT images from 7 years ago until hospitalization for headache Fig. 1a–c: T2-weighted MRI. Fig. 1a: 7 years before admission. A large thrombosed aneurysm in the right PCA was 18 mm in size, and the thrombosed part was on the lateral side. The patient had no symptoms. Fig. 1b: 2 years before admission. The aneurysm size grew larger gradually. Fig. 1c: On admission, she had a sudden headache and rapid aneurysm growth, which was approximately 28 mm. Specifically, as the aneurysmal component, both the previous thrombosed portion and the blood flow cavity portion got larger. No subarachnoid or intracerebral hemorrhage was noted. Fig. 1d, e: Plain computed tomography. Fig. 1d: 1 year before admission. The aneurysm size was 18 mm. Fig. 1e: On admission, the aneurysm grew rapidly. MRI: magnetic resonance image, PCA: posterior cerebral artery.

Fig. 2

VAG and BOT images on admission Fig. 2ab: The aneurysm was 28 mm and located in the P2 segment of the right PCA at the bifurcation to the P3–4 segments and the temporal arteries. Fig. 2a: AP view of right VAG. Fig. 2b: Lateral view of right VAG. Fig. 2c: VR image of right vertebral 3D-RA. Fig. 2d-f: Coronal view of the MPR images on right vertebral 3D-RA. From a to d, front to back view, we suspected that the small vessels arising from the posterior temporal artery were suspected to be vasa vasorum, which fed the thrombosed part and subsequently the posterior temporal artery was formed once and ran backward. Arrow: posterior temporal artery, Arrowhead: small vessel suspected of being vasa vasorum Fig. 2gh: These images are from the balloon occlusion test. Fig. 2g: Right ICAG in arterial phase lateral view on BOT. A parieto-occipital artery and posterior temporal artery were demonstrated in retrograde. Black arrow: parieto-occipital artery, Black arrowhead: posterior temporal artery. Fig. 2h: Right ICAG in venous phase lateral view on BOT. A calcarine artery was demonstrated faintly in retrograde. Black double-headed arrow: calcarine artery, PCA: posterior cerebral artery, AP: anterio-posterior, MPR: multiplanar reconstruction, 3D-RA: 3-dimensional rotational angiography, VAG: vertebral angiography, VR: volume-rendering, BOT: balloon occlusion test, ICAG: internal carotid angiography.

Fig. 3

A schema: 3D-RA VR image of VAG Small vessels arising from the posterior temporal artery were vasa vasorum, which fed the thrombosed part. The aneurysm was located at the bifurcation to the P3–4 segments and the temporal arteries. A thalamogeniculate artery arose from the P2 segment, just proximal to the aneurysm. 3D-RA: 3-dimensional rotational angiography, VAG: vertebral angiography, VR: volume-rendering.

Fig. 4

Embolization of the posterior temporal artery including vasa vasorum, anterior temporal artery, and P3 segment. Fig. 4ab: Embolization of the posterior temporal artery and vasa vasorum using a mixture of N-butyl-2-cyanoacrylate and Lipiodol. Fig. 4a: Lateral view of angiography of right posterior temporal artery. Small vessels resembling vasa vasorum arising from the posterior temporal artery and feeding the thrombosed part of the aneurysm. Arrow head: vasa vasorum. Fig. 4b: The vasa vasorum and posterior temporal artery were embolized using a 25% mixture of N-butyl-2-cyanoacrylate and Lipiodol. Fig. 4cd: Anterior temporal artery embolization. Fig. 4c: Lateral view of angiography of right anterior temporal artery. An Excelsior SL-10 microcatheter was advanced into the origin of the anterior temporal artery. Fig. 4d: Anterior temporal artery embolization was performed using a 25% mixture of NBCA and Lipiodol. Fig. 4ef: P3 segment embolization. Fig. 4e: Anteroposterior view of the posterior cerebral angiography before embolization. An Excelsior SL-10 was advanced into the P3 segment using a 0.012 GT microguidewire with a double angle tip. Fig. 4f: Coil embolization was performed using a total of 11cm coils.

Fig. 5

Embolization of intra-aneurysm and proximal P2 segment Fig. 5a: The aneurysm was roughly packed with 189cm coils, and the proximal P2 segment was embolized using 17cm coils to prevent occlusion of the thalamogeniculate artery. Fig. 5b: Image after aneurysm and proximal P2 segment embolization, indicating a thalamogeniculate artery. Fig. 5c: Final right vertebral angiography, anteroposterior view. Fig. 5d: Final right vertebral angiography, lateral view. Fig. 5e: Final right internal carotid angiography, lateral view, which indicated a parieto-occipital artery and a posterior temporal artery on delayed phase. Arrow: Parieto-occipital artery, Arrow head: Posterior temporal artery. Fig. 5f-h: Fluid-attenuated inversion recovery image. Fig. 5f: 2 days after the procedure. No change in aneurysm size was seen, and subarachnoid hemorrhage was not detected. However, cerebral infarction developed in the right temporal lobe, and midbrain edema was noted. Fig. 5g: 2 months after the procedure. Fig. 5h: 1 year after the procedure. Midbrain edema disappeared, and the aneurysm size decreased. The high signal intensity of the aneurysm at 2 months indicated thrombosis and iso-intensity at 1 year demonstrated