Image control after aneurysm clipping: Is 3D computed tomogram angiography enough?

Cerebral digital subtraction angiography (DSA) remains the gold standard for the control of aneurysmal remnants after surgical clipping. Despite being associated with minimal risks, it is an invasive procedure far from being iatrogenia free. Furthermore, it has limited availability which may prolong patient's postoperative stay. On the other hand, the image quality of computed tomography angiography (CTA) has improved significantly over the past decades providing a valuable alternative to DSA. The objective of this study was to compare the capacity of CTA and DSA to detect clinically significant aneurysmal remnants.

From a prospective series of surgically treated aneurysms, those with postoperative CTA and DSA were retrospectively included in the study. A three-dimensional reconstruction of the CTA was performed using the Brainlab Elements software and the results were compared with those of the DSA. In addition, variables that could affect the three-dimensional reconstruction were collected, such as the number of clips per aneurysm and previous clipping or embolization. In case of an aneurysm remnant, its size was also recorded.

Between January 2020 and January 2022, a total of 42 patients in whom 52 aneurysms were clipped (8 of them ruptured) were included. CTA presented a sensitivity of 50% and a specificity of 97% in the detection of aneurysmal remnants. The cases in which CTA did not detect the aneurysmal remnant were previously embolized aneurysms or complex aneurysms that required neck reconstruction with 3 or more clips. None of the remnants undetected by CTA were significant enough to warrant retreatment of the aneurysm.

Excluding complex aneurysms (previously embolized or requiring surgical reconstruction with 3 or more clips), three-dimensional reconstructions of CTA images showed excellent results in detecting clinically significant postoperative aneurysm remnants and may obviate the need for a the more invasive and less available DSA.