Quantification of Intracranial Aneurysm Morphodynamics from ECG-gated CT Angiography

Rationale and Objectives: Aneurysm morphodynamics is potentially relevant for assessing aneurysm rupture risk. A method is proposed for automated quantification and visualization of intracranial aneurysm morphodynamics from ECG-gated computed tomography angiography (CTA) data. Materials and Methods: A prospective study was performed in 19 aneurysms from 14 patients with diagnostic workup for recently discovered aneurysms (n=15) or follow-up of untreated known aneurysms (n=4). The study was approved by the IRB (Institutional Review Board) of the hospital and written informed consent was obtained from each patient. An image post-processing method was developed for quantifying aneurysm volume changes and visualizing local displacement of the aneurysmal wall over a heart cycle using multiphase ECG-gated (4D) CTA. Percentage volume changes over the heart cycle were determined for aneurysms, surrounding arteries and the skull. Results: Pulsation of the aneurysm and its surrounding vasculature during the heart cycle could be assessed from ECG-gated CTA data. The percentage aneurysmal volume change ranged from 3 -18%. Conclusion: ECG-gated CTA can be used to study morphodynamics of intracranial aneurysms. The proposed image analysis method is capable of quantifying the volume changes and visualizing local displacement of the vascular structures over the cardiac cycle.