Introduction: Enlargement of unruptured aneurysms indicates an increased risk of rupture. Assessment of aneurysm growth is typically based on aneurysm max diameter. However, this method is often unreliable due to factors such as the degree of contrast enhancement, tilting among studies and artifacts.
Hypothesis: Three-dimensional modeling can help to judge aneurysm growth.
Methods: All aneurysm patients who underwent CTA (1.0-mm slice thickness) with at least one follow-up in 2015, were reviewed. Intracranial saccular aneurysms were selected and fusiform, dissecting and mycotic aneurysms were excluded. Growth was defined as more than a 0.5 mm increase in size compared with the first study. 3D models were created from the source data using 3D-slicer (http://www.slicer.org). Aneurysm extraction from the parent artery was performed semi-automatically and volume and surface area were calculated using vascular toolkit (http://www.vmtk.org). The Mann-Whitney test and ROC curve analysis were applied to compare cases which increased in size with no-change cases.
Results: This research included 59 aneurysms in 51 patients that underwent 250 CTA, with follow-up duration of 50.0 ± 50.5 months. Nine aneurysms increased in size. In 5 of 9 cases, follow-up studies prior to growth detection were available. In these cases, maximum diameter change from the first study was not significant (P = 0.169). By contrast, volume and area were significantly different (P = 0.046 and 0.046, respectively). On ROC analysis, AUCs of maximum diameter, volume, and area changes were 0.7, 0.772 and 0.772.
Conclusions: Calculating volume and area changes was useful to judge aneurysm growth earlier than size measurement.