Sato T, et al. - Thirteen patients with 14 thrombosed intracranial aneurysms were recruited in a study by the experts in order to examine wall microstructures via gadolinium-enhanced 7T MR imaging. To recognize the gadolinium-enhancing microstructures, tissue samples were available in 5 cases, and histopathologic findings were compared with 7T MR imaging. Partial or complete inner wall enhancement was observed as associated with neovascularization of the inner wall layer and the adjacent thrombus. In the outer aneurysm wall layer, additional partial or complete outer wall enhancement could be defined by the development of vasa vasorum. The double-rim enhancement equated with perifocal edema and wall histologic findings were indicative of instability. Hence, using high-resolution gadolinium-enhanced 7T MR imaging, two distinct aneurysm wall microstructures accountable for gadolinium enhancement not depictable at lower spatial resolutions could be imaged in vivo.