Selective Occipital Artery–Posterior Cerebral Artery Bypass Guided by Fusion Imaging and Short-Segment Parent Artery Occlusion for a Partially Thrombosed Posterior Cerebral Artery Aneurysm: A Case Report

Introduction: Partially thrombosed aneurysms of the posterior cerebral artery (PCA), especially in the P2 segment, pose considerable treatment challenges owing to complex anatomy and ischemic risk. Case Presentation: We report a 49-year-old woman with a partially thrombosed dissecting P2 aneurysm treated using selective occipital artery–PCA bypass guided by digital subtraction angiography–magnetic resonance fusion imaging, followed by endovascular occlusion using Target Tetra coils. Postoperative imaging confirmed bypass patency and complete aneurysm obliteration without infarction or neurological deficit. Conclusion: We highlight a feasible treatment strategy for complex PCA aneurysms, emphasizing the importance of fusion imaging and targeted embolization in minimizing complications and preserving function.