ORIGINAL RESEARCH Visualizing Wall Enhancement Over Time in Unruptured Intracranial Aneurysms Using 3D Vessel Wall Imaging Bing Tian, MD , 1,2 * Shahed Toossi, MD, 3 Laura Eisenmenger, MD, 1 Farshid Faraji, 1 Megan K. Ballweber, 1 S. Andrew Josephson, MD, 3 Henrik Haraldsson, PhD, 1 Chengcheng Zhu, PhD, 1 Sinyeob Ahn, PhD, 4 Gerhard Laub, PhD, 4 Christopher Hess, MD, PhD, 1 and David Saloner, PhD 1 Background: Few studies directed at assessing the visualization of the walls of unruptured aneurysms have used higher- resolution 3D MRI vessel wall imaging. Prospective longitudinal studies are also needed to screen vessel wall changes in unruptured aneurysms. Purpose: To compare the aneurysm wall visualization on pre- and post-3D isotropic T 1 -weighted Sampling Perfection with Application-optimized Contrasts by using different flip angle Evolutions (SPACE) images and to explore whether there is a change in wall enhancement at follow up. Study Type: Prospective. Population: Twenty-nine patients with a total of 35 unruptured intracranial aneurysms. Sequence: 3D T 1 -weighted pre- and postcontrast SPACE (0.5 mm isotropic) at 3.0T. Assessment: The aneurysm wall visibility (0–5 scale) between pre- and postcontrast images as well as the wall enhance- ment (0–5 scale) between follow-up and baseline studies (6–30 months, average 12.7 months) were compared. Differences in wall visibility and enhancement were also investigated as a function of aneurysm diameter and location. Statistical Test: The Wilcoxon signed rank paired test was used to compare the wall visibility score between pre- and post- contrast SPACE images, as well as wall enhancement between follow-up and baseline. The Mann–Whitney and Kruskal– Wallis tests were used to investigate the enhancement difference between different diameters and locations. Results: Postcontrast images had significantly higher wall visibility (P = 0.01). A wall enhancement score ≥2 was found in 71% of the aneurysms. Changes in levels of wall enhancement were found in 17% of the aneurysms at follow-up studies, but those changes were small. Wall visibility and enhancement scores of large aneurysms were significantly higher than small ones (P < 0.001). Data Conclusion: 3D T 1 -weighted higher resolution SPACE can be used to assess changes in enhancement at follow-up studies. Contrast SPACE image provides better aneurysm wall visibility and improves visualization of the aneurysm wall. Level of Evidence: 2 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2018. U nruptured intracranial aneurysms are relatively common, being found in 3% of the adult population world- wide. 1 The large majority of unruptured intracranial aneu- rysms will never rupture. 2 However, once ruptured devastating stroke can result, with 27% mortality at 12 months after acute admission. 3 Aneurysms are considered to evolve mainly as the result of progressive degradation of the vascular wall in response to abnormal hemodynamics. 4 Traditional imaging methods provide valuable information on the lumen of intracranial aneurysms. However, there has View this article online at wileyonlinelibrary.com. DOI: 10.1002/jmri.26553 Received Aug 16, 2018, Accepted for publication Oct 9, 2018. * Address reprint requests to: B.T., Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94122. E-mail: bing.tian@hotmail.com From the 1 Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA; 2 Department of Radiology, Changhai Hospital of Shanghai, Shanghai, P.R. China; 3 Department of Neurology, University of California, San Francisco, California, USA; and 4 Siemens Healthcare, Erlangen, Germany © 2018 International Society for Magnetic Resonance in Medicine 1