3T MRI - 3D DSA Fusion Technique on Posterior Cerebral Artery Dissecting Aneurysm: Understanding a Potential Pathophysiologic Mechanism.

SUMMARY: We aimed to show the anatomical relationship between a dissecting aneurysm of the posterior cerebral artery (PCA) and tentorial free edge to understand the pathophysiologic mechanism. A 52-year-old woman with a history of head trauma presented with dizziness and numbness in her left fingers. 3D DSA showed a dissecting aneurysm of the right P2-P3 segment of PCA. The fusion of 3D DSA and 3T MRI was performed at the dedicated workstation using three pairs of landmarks including the ICA termination, MCA bifurcation and A1-A2 junction of the right ACA. Fusion of 3D DSA and 3T MRI clearly demonstrated the dissected segment of PCA crossed the tentorial free edge twice. The fusion images support the direct trauma hypothesis of dissecting aneurysm of the P2-P3 segment of PCA. This novel imaging technique shows future potential to be used to understand the anatomical relationships between various vascular lesions and surrounding structures.