Wall motion at 4D-CT angiography and surgical correlation in unruptured intracranial aneurysms: a pilot study

Unruptured intracranial aneurysms (UIAs) are reported more frequently nowadays but their management is not well established; it depends on different structural features of the aneurysms and on multiple patient's risk factors. With this prospective observational study we report our preliminary experience by using four-dimensional (4D) computed tomographic (CT) angiography with ECG-gated reconstructions in the evaluation of dynamic modifications of the aneurysm wall, as a potential predicting factor of growth or rupture. The novelty of this study consists in the correlation between Angio 4D-CT angiography images and surgical findings; only few scientific papers, in fact, have studied this issue.

Thirty-one patients (1 male, 30 females; 59.0±12.7 years old) with 43 unruptured aneurysms (medium size: 5.2±3.0 mm) were studied. ECG-triggered 4D-CT angiography was performed with a 320-detector CT system (Aquilion ONE; Toshiba Medical Systems Corporation, Ōtawara, Japan); ECG-gated reconstruction was performed for visualizing local displacement of the aneurysmal wall over a heart cycle. In the aneurysms surgically treated in our institution we were able to compare the macroscopic features of the aneurysm wall with 4D-CTA findings. We performed long-term follow-up on untreated patients.

Pulsation was detected in 13 of 43 unruptured aneurysms. Eighteen aneurysms were treated: thirteen were surgically treated and five underwent embolization with detachable coil placement. In nine aneurysms surgically treated in our institution (5 with pulsation and 4 without) we observed a significant correlation between 4D-CTA findings and macroscopic features of the aneurysms wall, in particular the pulsations detected at 4D-CTA study have shown to correspond to dark-reddish thinner wall at surgery.

Our data confirm the previous reports concerning the reliability of 4D-CT angiography with ECG-gated reconstructions in defining the dynamic and structural features of the aneurysm wall. Moreover, optimal correlation rate between the findings provided by the 4D-CTA and the macroscopic surgical evaluation support a possible role of this technique to identify aneurysms with a higher risk of rupture.