Assessment of microscope-integrated indocyanine green angiography during intracranial aneurysm surgery: A retrospective study of 120 patients

Aims: The purpose of this study was to assess the clinical value of indocyanine green angiography (ICG) in intracranial aneurysm surgery by comparing the findings with postoperative angiographic results.
Materials and Methods: One hundred and twenty patients with 148 intracranial aneurysms were included. ICG angiography was performed before and/or after the aneurysm clipping. A near-infrared excitation light illuminated the operation field, ICG was injected intravenously. The intravenous fluorescence was imaged with a video camera integrated into the microscope.
Results: A total of 208 investigations of ICG angiography were performed. Aneurysm clipping was applied in 120 patients. Incomplete clipping was detected in four patients. Parent and/or branching artery stenosis was found in five patients. Delayed perfusion of ICG was detected in one patient. Postoperative digital subtraction angiography (DSA) was performed in 108 patients. The postoperative angiographic results were consistent with findings on intraoperative ICG angiograms in 100 patients (92.6%). In three cases, a mild stenosis was seen on DSA, which was not detected intraoperatively using ICG angiogram. In one patient, middle cerebral artery stenosis was found. Three patients had small residual aneurysms found by postoperative DSA. The remaining one developed a severe cerebral vasospasm.
Conclusions: ICG angiography is a simple, reliable and cost-effective method. It provides real-time information in detecting the patency of parent, branching, perforating arteries and residual aneurysm. This technique may be a useful adjunct to improve the quality of intracranial aneurysm surgery.

Keywords
Cerebral angiography, indocyanine green angiography, intracranial aneurysm