CTA-based angle selection for diagnostic and interventional angiography ofsaccular intracranial aneurysms

Coil embolization is a safe treatment for cerebral aneurysms only if the wi dth of the neck in relation to the fundus of the aneurysm is small, Therefo re, accurate visualization of the aneurysmal neck is required both in the d iagnostic process and during the intervention. Conventional digital subtrac tion angiography (DSA) is still the preferred modality for the examination of cerebrovascular abnormalities like aneurysms, but it often does not prov ide the required morphological characteristics due to the suboptimal select ion of projection angles and resulting overprojections of surrounding vascu lature. This paper presents a method for performing a computer-assisted calculation of the optimal projection angles for DSA by post-processing computed tomog raphic angiography (CTA) volume data using ray-casting techniques and a com bination of image processing algorithms, By means of phantom studies, retro spective simulations of angiograms, and in vivo applications of calculated optimal viewing angles, it is demonstrated that the proposed method results in better angiographic projections of the neck of saccular aneurysms with small neck-fundus ratio than those acquired at standard angles prescribed b y clinical protocols.