Visualizing wall enhancement over time in unruptured intracranial aneurysms using 3D vessel wall imaging

Abstract

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 T1‐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 T1‐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 enhancement (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 postcontrast 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 T1‐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 2019;50:193–200.

Presence of Vessel Wall Hyperintensity in Unruptured Arteriovenous Malformations on Vessel Wall Magnetic Resonance Imaging: Pilot Study of AVM Vessel Wall “Enhancement”

“…Although many studies support the relationship between vessel wall “enhancement” and vessel rupture and/or instability, several complicating factors exist in the imaging of vascular lesions. For one, some studies are now finding that a proportion of vascular malformations that enhance demonstrate persistent and stable “enhancement” over time with no symptomatology or subsequent rupture ( Tian et al, 2019 ). This persistent hyperintensity on imaging could indicate remodeled vessel wall without active inflammation as well as true persistent inflammatory changes; however, more studies and larger, longitudinal studies are needed to investigate if symptomology, rupture, and/or mortality are associated with vessel wall hyperintensity as well as histopathologic correlation with sites of enhancement versus non-enhancement.…”

“…Some of the most commonly employed VW-MRI sequences are variable refocusing flip angle (VRFA) sequences with T1 or proton density-weighted pre- and post-contrast imaging (VISTA; Philips Healthcare), sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE; Siemens), and CUBE software (GE Healthcare) ( Young et al, 2019 ). While VRFA sequences are adequate in most cases, because gadolinium shortens T1 relaxation time, “black blood” suppression in areas of abnormal or even normal in-plane flow can be diminished, potentially causing unsuppressed contrast in flowing blood, artifactually appearing as vessel wall contrast “enhancement.” Examples of this are seen with turbulence and recirculation within aneurysms, slow flow within dilated lumens, and retrograde filling of distal collateral branches with proximal occlusion ( Mandell et al, 2017 ; Tian et al, 2019 ); however, this altered blood flow leading to potential incomplete suppression on VFRA sequences may in and off itself be a high risk feature, such as areas of low wall sheer stress in aneurysms ( Boussel et al, 2008 ), although this hypothesis has yet to be well investigated. Preparation pulses can be helpful in cases where this flow-related artifact is occurring, such as motion-sensitized driven equilibrium (MSDE) which uses flow-sensitive dephasing gradients ( Young et al, 2019 ).…”

“…Initially, the majority of studies were focused on steno-occlusive cerebrovascular disease such as intracranial atherosclerosis ( Vergouwen et al, 2011 ; Skarpathiotakis et al, 2013 ; Mossa-Basha et al, 2015 ), primary central nervous system vasculitis ( Mandell et al, 2012 ; Obusez et al, 2014 ; Mossa-Basha et al, 2015 ), reversible cerebral vasoconstriction syndrome ( Mandell et al, 2012 ; Obusez et al, 2014 ; Mossa-Basha et al, 2015 ), drug-induced vasculopathies ( Han et al, 2008 ), and intracranial dissections ( Chung et al, 2014 ; Natori et al, 2014 ). More recently, there has been increased enthusiasm for the utilization of VW-MRI to further characterize vascular malformations, with intracranial aneurysms being the most commonly studied lesion ( Matouk et al, 2013 , 2016 ; Edjlali et al, 2014 ; Nagahata et al, 2016 ; Tian et al, 2019 ; Wang et al, 2019 ; Liu et al, 2020 ; Zhu et al, 2020 ). Current evidence suggests that vessel wall hyperintensity on post-contrast VW-MRI, often referred to as vessel wall “enhancement,” is associated with ruptured ( Matouk et al, 2013 ; Nagahata et al, 2016 ; Wang et al, 2019 ), symptomatic ( Zhu et al, 2020 ), and unstable ( Edjlali et al, 2014 ; Edjlali et al, 2018 ) aneurysms.…”

Statin treatment for unruptured intracranial aneurysms study: a study protocol for a double-blind, placebo-controlled trial

“…Viewing the two studies side by side will allow rapid identification of the territory of interest from the CE-MRA and represents an approach that would be useful in the clinical setting. [20][21][22] Two neuroradiologists (with >10 years and >5 years of experience in vascular neuroimaging, respectively), who will be blinded to the clinical data but aware of the patients' aneurysm location(s), will independently review the images with a workstation (syngo workstation; Siemens Healthineers, Erlangen, Germany). Qualitative wall enhancement scores and quantitative parameters will be assigned.…”

“…Aneurysm wall signal intensity equal to or greater than that of the pituitary infundibulum will be regarded as enhancement. A scale of 0-5 will be used to grade the aneurysm wall enhancement, with 0 signifying that the aneurysm wall has significant artefacts and/or it is not possible to determine whether the vessel wall is enhanced, 22 1 signifying no enhancement, 2 signifying aneurysm wall enhancement over <25% of the aneurysm surface, 3 signifying wall enhancement over 25%-50% of the aneurysm surface, 4 signifying wall enhancement over 50%-75% of the aneurysm surface and 5 signifying wall enhancement over >75% of the aneurysm surface.…”