Infectious (mycotic) aneurysms are rare with high mortality and are most commonly found at the distal branches of the middle cerebral artery (MCA). Because aneurysms of the distal MCA are located deep in the Sylvian fissure and are small in size, intraoperative identification and safe clip occlusion of these aneurysms are challenging. Thus, the use of intraoperative imaging and navigation can be beneficial. We describe the use of intraoperative real-time 3D ultrasound “angiography” (3D-iUS) in localizing and occlusion control of a ruptured MCA M3 segment mycotic aneurysm. To our knowledge, its application in the surgery of a ruptured mycotic distal MCA aneurysm is not yet reported.
 A 54-year-old woman with a history of septic thrombophlebitis treated with long-term antibiotic therapy presented with sudden onset of headaches, dysphasia, and seizures. Computed tomography (CT) revealed subarachnoid hemorrhage in the distal portion of the left Sylvian fissure. Digital subtraction angiography (DSA) showed an aneurysm at the peripheral branch of the M3 segment of the MCA with characteristics of an infectious aneurysm. A microsurgical treatment was decided. 3D-iUS scan showed an aneurysm within the Sylvian fissure at a depth of 5 cm. The aneurysm was clipped and a repeated 3D-iUS scan showed total occlusion of the aneurysm and patency of the parent artery. The intraoperative findings were confirmed with a postoperative DSA.
 Our case report shows that real-time 3D-iUS, despite its limitations, is an important tool to locate and ascertain the successful clip occlusion of an aneurysm, especially when intraoperative angiography (IA) and indocyanine green (ICG) videoangiography are not available due to low-income settings.

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