Comparison of three-dimensional intracranial aneurysmal wall enhancement features based on different modeling modalities

Abstract

BACKGROUND: Aneurysmal wall enhancement (AWE) is a new imaging biomarker of unstable intracranial aneurysms (IAs). Several studies have focused on characterizing AWE in three-dimensional (3D) space. However, methods to generate 3D aneurysm models are diverse, which may lead to variations in AWE mapping. This study aimed to compare the variability of 3D aneurysm models based on different imaging modalities. METHODS: We prospectively recruited three patients who presented with three saccular IAs. Two of the aneurysms were located in the vertebral artery and one in the middle cerebral artery (MCA). Patients underwent both time-of-flight magnetic resonance angiography (TOF-MRA) and contrast-enhanced magnetic resonance imaging (CE-MRI) in a single MRI scan. Two different 3D aneurysm models were generated, one each from TOF and pre-contrast T1 images. The corresponding post-contrast T1 images were registered to the TOF and pre-contrast T1 images. The signal intensities of the aneurysm wall were mapped to each aneurysm model. AWE mapped from the 3D models of TOF and pre-contrast T1 images was quantified and visualized. The values and distributions of AWE generated by the two methods were compared. RESULTS: The 3D-AWE of the T1 model showed higher signal intensity than that of the TOF model. The average (178.71 vs 172.25, 143.30 vs 138.40, and 164.21 vs 140.28, respectively), maximal (361 vs 334, 249 vs 210, and 463 vs 411, respectively), and minimal (59 vs 58, 58 vs 56, and 63 vs 51, respectively) signal intensity values were all higher in T1 models. One case with the aneurysm in the MCA showed extra wall enhancement in the aneurysm neck. CONCLUSION: Studies on 3D-AWE should consider the variability of 3D aneurysm models based on different imaging modalities in the future.