Intracranial aneurysms are heterogeneous in histopathology and imaging appearance. The biological behavior of different types of aneurysms is now known to depend on the structure and physiology of the aneurysm wall itself in addition to intraluminal flow and other luminal features. Aneurysm wall structure and imaging markers of physiology such as aneurysm wall enhancement have been assessed in many prior investigations using conventional-resolution MRI. Recently, high-resolution vessel wall imaging (HR-VWI) techniques with MRI have been introduced. Reports of findings on high-resolution imaging have already emerged for many types of aneurysms demonstrating detailed characterization of wall enhancement, thickness, and components, but many questions remain unexplored. This review discusses the key HR-VWI literature to date. Aneurysm wall findings on conventional-resolution MRI are also discussed as these may help one understand the potential utility and findings on HR-VWI for various aneurysm types. The authors have illustrated these points with several examples demonstrating both features already described in the literature and novel cases demonstrating the potential for future clinical and research applications.
Keywords: ACA = anterior cerebral artery; CTA = CT angiography; DANTE = delayed alternating with nutation for tailored excitation; DIR = double inversion recovery; FOV = field of view; HIV = human immunodeficiency virus; HR-VWI = high-resolution vessel wall imaging; ICA = internal cerebral artery; IR = inversion recovery; MCA = middle cerebral artery; MPIR = magnetization-prepared inversion recovery; MRA = MR angiography; MSDE = motion-sensitive driven equilibrium; PCA = posterior cerebral artery; PD = proton density; QIR = quadruple inversion recovery; SAH = subarachnoid hemorrhage; SPACE = sampling perfection with application optimized contrast using different flip angle evolutions; VISTA = volumetric isotropic turbo spin echo acquisition; VRFA = variable refocusing flip angle; VZV = varicella zoster virus; aneurysm wall; high-resolution vessel wall imaging; intracranial; vascular disorders.