On the feasibility of densitometric assessment of cerebral aneurysms

Computer-aided operator-interactive densitometry was used to study the feasibility of quantitating the radiographic images of cerebral aneurysms. Contrast-filled tubings of varying diameter were used to investigate the linearity of the system and to assess the general accuracy and reproducibility of the densitometric method. To study the reproducibility of the technique on aneurysms, a vein pouch aneurysm model was developed in rabbits. Inter- and intra-operator errors were determined by four observers, who performed multiple measurements on various projections of aneurysm images taken both in vitro and in vivo. These errors ranged between 3 and 8% for the in vitro data, and 7 and 22% for the in vivo data. It was found that the current approach that utilizes the linear segment of the film-screen characteristic curve has to be extended to involve the non-linear segment at the 'toe' section of the characteristic curve for future clinical applications.