Optical Coherence Tomography for Intracranial Aneurysms: A New Method for Assessing the Aneurysm Structure

BACKGROUND: There is a lack of precise methods for predicting the risk of aneurysm rupture. Therefore, prophylactic treatment is used, which leads to unnecessary potential complications. A new modality enabling a more accurate risk assessment is needed. Optical coherence tomography (OCT) is a new-generation imaging technology that has astonishing resolution for vascular imaging. In this study, OCT was used for the evaluation of intracranial aneurysms. METHODS: In vivo OCT imaging was performed for aneurysms induced in 6 rabbits and in 9 intracranial aneurysm patients. Catheters were cut short to prevent any extra length from damaging aneurysms and tissues. Images of both the parent artery and the aneurysm at multiple viewing angles were obtained using rotational OCT scanning. RESULTS: The OCT images of rabbits correlated well with histologic sections. The 3-layered architecture of the parent arteries was explicitly shown. Ruptured intracranial aneurysms manifested complete breakdown of the wall structure; however, this was not observed in any unruptured aneurysms. The OCT images of unruptured intracranial aneurysms demonstrated a trend of degradation by showing the gradual disappearance of the demarcation between the layers or incomplete apoptosis in layer structures. CONCLUSION: OCT is the most precise imaging modality because it provides detailed information regarding the aneurysm structures, thus enabling more distinct insight into the vascular construction of intracranial aneurysms.