PMC3130464_01
Case 1: neuroimaging findings on admission. (a) Axial computed tomograph (CT) showing an intracerebral hemorrhage in the right frontal lobe. (b, c) Digital subtraction angiograph (DSA) showing severe right middle cerebral artery stenosis (parenthesis) and two aneurysms in the posterior internal frontal artery and paracentral artery of the ACA (thick arrow and arrowhead, respectively) that functioned as collateral pathways
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F1
Computed tomography (CT) performed at admission revealed intracerebral hemorrhage in the right frontal lobe [Figure 1a]. ACA [Figure 1b and c]. Although an echocardiogram and blood test did not indicate infective endocarditis, due to their peripheral locations, we suspected the aneurysms to be mycotic pseudo-aneurysms and we started conservative antibiotic treatment.
Case 1. (a) Follow-up DSA obtained on day 5. The aneurysm in the posterior internal frontal artery of the ACA showed enlargement (thick arrow). (b) Intraoperative DSA showing obliteration of the aneurysms in the posterior internal frontal artery and paracentral artery (thick arrow and arrowhead, respectively)
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F2
The aneurysm in the paracentral artery was not enlarged [Figure 2a]. Intraoperative DSA confirmed the obliteration of both aneurysms [Figure 2b].
Case 1. (a) Photograph of the trapped and resected aneurysm in the posterior internal frontal artery. (b) The clipped aneurysm in the paracentral artery. (c) Hematoxylin and eosin staining of the trapped and resected aneurysm. Parts of the aneurysmal wall consisted of three layers. (d) Weigert staining of the resected aneurysm. Elastic fibers were stained blue/purple; the point of rupture was devoid of elastic fibers (thick arrow)
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F3
After evacuation of the intracerebral hematoma, we found that the ruptured aneurysm in the posterior internal frontal artery did not involve any arterial branches and so it was surgically trapped and resected [Figure 3a]. The neck of the other unruptured aneurysm in the paracentral artery was clipped [Figure 3b]. These findings were indicative of a true ruptured saccular aneurysm [Figure 3c and d].
PMC3130464_02
Case 2. (a) CT performed at the time of admission showed diffuse subarachnoid hemorrhage and hemorrhages in the fourth ventricle. (b) 3D-DSA also acquired at admission revealed severe basilar artery (BA) stenosis (long arrow) just distal to the vertebral artery union. There were three arterial dilations (thick arrows): two were in a posterior inferior cerebellar artery (PICA)-anterior inferior cerebellar artery (AICA) anastomosis (arrowhead) and one was in the BA trunk distal to a stenotic site
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CT obtained at admission revealed subarachnoid hemorrhage (SAH) mainly distributed in the posterior fossa [Figure 4a]. None of the aneurysms manifested branch involvement [Figure 4b].
Case 2. (a) 3D-DSA acquired on day 7. The thick arrow indicates the enlarged aneurysm in the PICA-AICA anastomosis. (b) DSA obtained on day 15 pre-embolization. The thick arrow points to an aneurysm in the PICA-AICA anastomosis. There is aneurysmal enlargement. (c, d) DSA performed after selective aneurysmal coil embolization with parent artery preservation. The thick arrow in (c) indicates the preserved PICA-AICA anastomosis. The thick arrow in (d) points to a small neck remnant left over from the embolized aneurysm
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F5
Follow-up DSA performed on day 7 demonstrated that the arterial dilation in the PICA-AICA anastomosis had progressed to a saccular aneurysm with a 2-mm neck size; it was 2.7 mm wide and of 2.9 mm in height [Figure 5a]. At this point, the target aneurysm had further increased in size [Figure 5b]. Post-treatment DSA showed a small aneurysmal neck remnant; blood flow in the PICA-AICA anastomosis was preserved [Figure 5c and d].