Indocyanine green visualization of middle meningeal artery before craniotomy during surgical revascularization for moyamoya disease

Background: The middle meningeal artery (MMA) is well known to function as an important collateral channel to the territory of the anterior cerebral artery in moyamoya disease. This study was aimed to evaluate whether indocyanine green (ICG) videoangiography could visualize the anterior branch of the MMA before craniotomy during surgical revascularization for moyamoya disease. Methods: This study included 19 patients who developed TIA, ischemic stroke or hemorrhagic stroke due to moyamoya disease. Plain CT scan and three-dimensional time-of-flight MR angiography were performed in all patients before surgery. All of them underwent superficial temporal artery to middle temporal artery anastomosis and indirect bypass on 27 sides in total. Results: ICG videoangiography could clearly visualize the anterior branch of the MMA in 10 (37%) of 27 sides. The patients with a “visible” MMA are significantly younger than those without. Radiological analysis revealed that ICG videoangiography could visualize it through the cranium when the diameter of the MMA is >1.3 mm and the sphenoid bone thickness over the MMA is <3.0 mm. The MMA could be preserved during craniotomy in all “visible” MMAs, but not in 4 (23.5%) of 17 “invisible” MMAs. The results strongly suggest that ICG videoangiography can visualize the anterior branch of the MMA before craniotomy in about one-third of patients with a large-diameter MMA (>1.3 mm) and thin sphenoid bone (<3.0 mm). Conclusion: ICG videoangiography is a safe and valuable technique to preserve the anterior branch of the MMA during craniotomy for moyamoya disease.