PMC9263357_01
Imaging of case 1. (A) CT shows subarachnoid hemorrhage concentrated at the perimesencephalic cistern with involvement of the fourth ventricle. (B) CTA reveals no underlying vascular lesions. (C,D) Angiograms of the left VA show a pseudoaneurysm (arrow) located in the hypoplastic and plexiform PICA. (C) shows a three-dimensional angiogram, and (D) shows a two-dimensional angiogram. (E) Angiogram of the left VA shows that the aneurysm and parent PICA are cast with Onyx, and other branches are visualized. (F) Follow-up MRI scan shows a minor brainstem infarction (arrow). CT, computed tomography; CTA, CT angiography; L, left; MRI, magnetic resonance imaging; PICA, posterior inferior cerebellar artery; VA, vertebral artery.
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F1
CT showed subarachnoid hemorrhage (SAH) concentrated at the perimesencephalic cistern with involvement of the fourth ventricle (Figure 1A). CT angiography (CTA) revealed no underlying vascular lesions (Figure 1B). Catheter angiography revealed that the left PICA was hypoplastic and plexiform. A pseudoaneurysm was located in the hypoplastic and plexiform PICA (Figures 1C,D). PICA were occluded with an Onyx liquid embolic system (Medtronic, Irvine, California, USA) (Figure 1E). Postoperatively, he showed no consciousness or movement disturbance. MRI only revealed the old brainstem infarction (Figure 1F).
PMC9263357_02
Imaging of case 2. (A) CT shows SAH concentrated at the cisterns around the brainstem and cerebellomedullary cistern. (B) CTA reveals no vascular abnormalities. (C) Angiogram of the right VA shows a pseudoaneurysm (arrow) located in the hypoplastic and plexiform PICA. (D) Superselective angiogram of the right PICA showing the pseudoaneurysm (arrow). (E) Angiogram of the VA shows that the aneurysm and parent PICA were cast with Onyx, and other branches are visualized. (F) Postoperative CT scan shows the location of casting Onyx (arrow) and partial resolution of the SAH. CT, computed tomography; CTA, CT angiography; PICA, posterior inferior cerebellar artery; R, right; SAH, subarachnoid hemorrhage; VA, vertebral artery.
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F2
CT showed SAH concentrated at the cisterns around the brainstem and cerebellomedullary cistern (Figure 2A). CTA revealed no vascular abnormalities that might be responsible for the SAH (Figure 2B). Catheter angiography showed that the right PICA was hypoplastic and plexiform. A pseudoaneurysm was detected in the plexiform PICA (Figures 2C,D). Then, the Onyx liquid embolic system was cast, successfully occluding the aneurysm and parent PICA (Figure 2E). SAH (Figure 2F). She was discharged to a local hospital for rehabilitation.