Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms

Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms Arndt-Hendrik Schievelkamp, Alexander Schnepper, Elke Hattingen This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7686862/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose This study aimed to compare aneurysm wall enhancement post-coil embolization between patients with and without subarachnoid hemorrhage (SAH). We hypothesized that ruptured aneurysms in SAH patients exhibit different enhancement patterns compared to incidentally found unruptured aneurysms. Potential confounding factors for wall enhancement, such as coil packing density and aneurysm size, were also assessed. Methods This retrospective cross-sectional single-center study included patients who underwent coil embolization for intracranial aneurysms. Subsequently, these patients were monitored with digital subtraction angiography and magnetic resonance imaging, which included a "black blood" contrast-enhanced sequence. Data were analyzed using ROI signal intensities (SI) and visual evaluation. Quantitative and visual assessments of aneurysm wall enhancement were compared between patients with and without SAH using the two-sided Student's t-test. In addition, linear regression was performed to explore the effects of coil density and aneurysm size on wall enhancement. Results Among the 31 patients studied, those with unruptured aneurysm without SAH showed higher wall signal intensities after embolization compared to SAH patients with ruptured and coil-embolized aneurysms (Visual assessment: p = 0.02; ROI measurements: SAH: 813 SI vs. no SAH: 1151 SI, p < 0.01). No significant correlation was found between coil packing density and wall enhancement, nor was there a significant impact of aneurysm size on the enhancement in visual assessment. Conclusion Aneurysm wall enhancement after coil embolization differs significantly between patients with and without SAH, suggesting that aneurysm rupture changes the characteristics of the aneurysm wall. Coil density and aneurysm size appear to have less influence on wall enhancement. Intracranial aneurysm wall enhancement coil embolization subarachnoid hemorrhage black-blood MRI Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION The prevalence of intracranial aneurysms is estimated to be 2% to 3% among the adult population [ 14 , 18 , 22 ]. The main risk of intradural aneurysms is aneurysm rupture, leading to subarachnoid hemorrhage (SAH), which is associated with significant mortality and morbidity in the affected patients. For both ruptured and unruptured intracranial aneurysms, established treatment options include endovascular approaches – such as coil embolization, which remains the most commonly used technique, as well as stent- and flow-diverter-assisted methods – and surgical clipping [ 1 , 4 , 17 , 19 ]. Ruptured aneurysms should be promptly managed with either clipping or endovascular treatment in order to prevent re-bleeding [ 2 , 21 ]. For unruptured aneurysms, treatment options may include conservative therapy, endovascular treatment, or clipping depending on the size, configuration and localization of the aneurysm [ 2 , 8 ]. To evaluate the need for interventional therapy in incidental and unruptured aneurysms, the risk assessment regarding an aneurysm rupture is a crucial factor. Despite various interim analyses of large intervention studies, this risk assessment remains controversial. High-resolution vessel wall MR imaging is discussed as a possible tool for characterizing and identifying cerebral aneurysms at increased risk of rupture [ 6 , 7 , 11 , 12 , 16 ]. However, only few studies have been published regarding aneurysm wall enhancement following coil embolization [ 3 , 10 ]. This study aimed to identify factors influencing aneurysm wall enhancement after coil embolization by comparing ruptured aneurysms in patients with SAH to incidentally detected unruptured aneurysms. The null hypothesis posits that there are no significant differences in aneurysm wall enhancement post-coil embolization between patients with and without SAH. To account for possible confounding variables, secondary hypotheses examined whether coil packing density or aneurysm size affected wall enhancement. Furthermore, the correlation between the amount of foreign material and wall enhancement was assessed. METHODS This retrospective cross-sectional single-center study was approved by the institutional review board. Patients with an incidentally detected intracranial aneurysm without symptoms and patients with subarachnoid hemorrhage (SAH), confirmed by clinical presentation and cranial computed tomography (CT), who underwent coil embolization treatment (in 10 cases stent-assisted) and were routinely followed up with digital subtraction angiography (DSA) and magnetic resonance imaging (MRI) were examined. The cohort included in this study was based on a predefined dataset from 2015 to 2016, established as part of a systematic follow-up program at our institution. All follow-up examinations (DSA and MRI) of patients with an intracranial aneurysm treated by coil embolization during this period have been included in this study. Follow-up MRI and DSA were performed approximately six months after coil embolization as part of the routine institutional protocol. Cases from later years could not be included due to changes in clinical workflows and imaging protocols, which affected data completeness and standardization. The only exclusion criteria were insufficient MR image quality due to severe artifacts from patient movement or the proximity to bony structures (skull base). To analyze our hypothesis, patients with and without SAH were divided into two different groups. All digital subtraction angiographies and MRI examinations were performed at our department's facility using a Philips Allura Xper FD20 for angiographies and a 3 Tesla scanner (Philips Achieva) for MRI. The MRI sequences obtained are shown in Table 1 . Table 1 List of the sequences obtained. Sequence Orientation TR [ms] TE [ms] Flip Angle ° Slice Thickness (mm) Voxel Resolution (mm³) T2W TSE Axial 3277 80 90 5 0,45 Single-shot Diffusion-weighted Imaging Axial 2548 40 90 5 1 Time-of-Flight Angiography Axial 19,5 3,7 20 1 0,2 T2W TSE Coronar 4137 80 90 2 0,2 T1W IR TSE Axial 5 2,5 15 2 1 T1W TSE -/+ GBCA Axial 624 13,4 90 5 0,49 Black Blood T1W IR TSE Axial 2263 13 90 2 0,43 3D T1W Fast-SE + GBCA Sagittal 8,31 3,8 8 1 1 * W: weighted; TSE: Turbo Spin Echo; IR: Inversion Recovery; GBCA: Gadolinium-based Contrast Agent The contrast-enhanced black-blood sequence was consistently acquired at a standardized time point following intravenous contrast agent administration as part of the institutional protocol. The measurements were performed by a graduate student after extensive training and under close supervision by an experienced neuroradiologist. Aneurysm wall enhancement was assessed using ROI measurements of signal intensities (SI) applied over the entire aneurysm; in each slice depicting the aneurysm in the black-blood T1-weighted sequence following intravenous administration of a Gadolinium-containing contrast agent (Fig. 1), focusing on maximal values to mitigate potential artifacts from coil material-induced signal loss. Additionally, visual evaluation using a template was conducted to complement the quantitative analysis. This was based on a 3-point Likert scale: 1 = no or minimal wall enhancement, 2 = moderate enhancement, 3 = strong enhancement. Representative examples are shown in FIG. 2. Coil density was estimated in the planar images of DSA using ROI measurement (FIG. 3) and assessed visually using a template (FIG. 4). The visual scale was developed in-house for this study and enabled standardized categorization of coil packing into low, medium, and high density. Statistical evaluation was performed using the two-sided Student's t-test to compare parameters between patients with and without SAH. Results with a p-value of p < 0.05 were considered significant. Linear regression was used to assess the potential impact of coil material packing density and aneurysm size on ROI measurement results. RESULTS The exclusion of examinations due to insufficient image quality led to the selection of 31 out of a total of 51 patients – consisting of 28 females and three males – with an average age of 56 (ranging from 39 to 79 years old). Among these participants, 14 were diagnosed with SAH. Table 2 provides a comprehensive overview of the patient group, including cases of stent-assisted coiling. Table 2 Overview of the test subjects and the aneurysms included in the evaluation. SAH (N=) No SAH (N=) Total (N=) Patients treated with coil embolization 14 17 31 Female 12 16 28 Male 2 1 3 Stent-supported coil treatment 4 6 10 Additional devices (e.g.; stent-in-stent) 2 0 2 Aneurysm largest diameter (mm) 10 2 3 5 Group "small aneurysms" ( 7 mm) 5 8 13 The study found no significant discrepancy in the size of aneurysms between those with and without SAH. Enhancement of aneurysm wall Visual assessment: Visual assessment revealed that aneurysms in patients without SAH exhibited a more pronounced increase in signal intensity of the aneurysm wall in contrast-enhanced T1-weighted black-blood sequences compared to those in patients with SAH (p = 0.02). ROI measurements: ROI measurements revealed higher maximal SI values in the aneurysms of patients without SAH compared to those with SAH (SAH: 813 SI vs. no SAH: 1151 SI, p < 0.01). A comparison of the mean values of the SI in the ROI measurements in the contrast-enhanced black blood sequence is shown in Fig. 5. The pertinent raw data is presented in Table 3 . Table 3 Maximal Signal Intensity (Max SI) values of the coil-treated aneurysms in the black blood T1-weighted sequence (BB-T1W) in patients with and without SAH Aneurysm Number SAH yes+/no- Localization Size in mm Max SI BB-T1W 1 + Basilar apex 8 1051 2 + Left posterior communicating artery 8 461 3 + Left posterior communicating artery 4 1190 4 + Anterior communicating artery 9 717 5 + Left internal carotid artery 12 1127 6 + Left internal carotid artery 7 384 7 + Vertebral artery 4 201 8 + Left posterior communicating artery 6 778 9 + Left posterior communicating artery 6 1089 10 + Right posterior communicating artery 14 1338 11 + Basilar apex 6 826 12 + Right internal carotid artery 2 1102 13 + Right posterior communicating artery 6 544 14 + Anterior communicating artery 5 535 15 - Left internal carotid artery 15 2135 16 - Basilar apex 8 939 17 - Left superior cerebellar artery 2 1159 18 - Left internal carotid artery 10 1256 19 - Basilar apex 8 491 20 - Basilar apex 8 985 21 - Left internal carotid artery 5 914 22 - Right middle cerebral artery 11 1256 23 - Left internal carotid artery 6 1193 24 - Left internal carotid artery 5 1001 25 - Left internal carotid artery 13 1694 26 - Right internal carotid artery 5 1027 27 - Right posterior communicating artery 4 1421 28 - Left internal carotid artery 8 976 29 - Right posterior inferior cerebellar artery 4 1094 30 - Basilar apex 7 1162 31 - Right internal carotid artery 3 881 Larger aneurysms exhibited higher signal intensities in ROI measurements compared to smaller ones (p < 0.01), a distinction not reflected in visual evaluations. However, linear regression analysis showed that aneurysm size did not have a significant impact on the differences in ROI measurements in the black-blood sequence between patients with and without SAH. Coil packing: No significant variance in coil packing density in relation to the size of the aneurysm was found, nor was there a discernible difference in coil packing density when comparing patients with and without SAH. Linear regression analysis evaluating the effects of coil packing density on wall enhancement revealed insignificant influence. DISCUSSION This study compares aneurysm wall enhancement in patients who underwent coil embolization and were followed-up with DSA and MRI, who had either incidentally detected intracranial aneurysms without symptoms or who had undergone SAH. We found that aneurysms in patients without SAH showed more pronounced wall enhancement in both ROI measurements and visual assessments. While coil density showed no significant impact on aneurysm wall enhancement, notable differences in wall enhancement between patients with and without SAH indicate that aneurysm rupture and/or the presence of SAH influences post-embolization wall behavior. Increased accumulation of contrast agent in the aneurysm wall following endovascular coiling has been described [ 3 , 10 ]. It has been hypothesized that post-interventional remodeling processes, including the formation of a peripheral thrombosis in the aneurysm sac, may be responsible for this phenomenon [ 23 ]. Increasing vascularization of the aneurysm wall with ingrowth of vascularized tissue into the coil material has been described [ 13 , 23 ]. Histological analysis has revealed an increase in vascularization of the aneurysm wall, accompanied by the ingrowth of vascularized tissue into the coil material [ 13 ]. Additionally, an elevated inflammatory reaction within the aneurysm wall, characterized by an influx of inflammatory cells, has been observed [ 13 ]. These findings are in line with recent histo-radiological evidence demonstrating that aneurysm wall enhancement strongly correlates with inflammatory cell infiltration, neovascularization, and wall degeneration, supporting its role as an independent imaging marker of aneurysm instability [ 5 ]. Our findings indicate accumulation of contrast agent within the aneurysm wall following coiling treatment. Aneurysm wall enhancement was significantly lower in patients presenting with SAH compared to those with incidentally detected aneurysms. One potential explanation is a reduction in wall tension when the aneurysm ruptures during SAH. Recent studies show that aneurysm wall enhancement is linked to higher wall tension and unfavorable hemodynamic conditions, regardless of aneurysm size [ 20 ]. In line with this, several clinical studies have found that pronounced aneurysm wall enhancement is associated with aneurysm instability, such as rupture risk and growth [ 6 , 11 , 12 , 13 , 15 ]. The result of our study underlines that the wall tension or the decrease thereof has a decisive influence on the enhancement behavior of aneurysms. Histological analysis indicated that, following rupture, the aneurysm wall undergoes remodeling, which is demonstrated by increased scar tissue formation, reduced inflammatory response, and decreased vascularization of the aneurysm wall [ 9 ]. The increased tissue stress with an inflammatory response, caused by increased tension in the wall of unruptured aneurysms compared to ruptured aneurysms, may be a potential explanation for the increased aneurysm wall enhancement observed [ 13 ]. The study reported that aneurysm size did not differ significantly between individuals with SAH and those without. As mentioned previously, larger aneurysms exhibited higher signal intensities in ROI measurements compared to smaller ones, a distinction not mirrored in visual evaluations. An explanation for this could be that larger aneurysms have higher wall tension, which would be expected to correlate with increased enhancement. Nonetheless, our regression analysis did not confirm a significant impact of aneurysm size on the differences in ROI measurements between patients with and without SAH. A higher accumulation of contrast agent within the aneurysm wall has been linked to an elevated risk of rupture [ 6 , 11 , 12 , 13 , 15 ]. The lack of a significant finding in our study might be attributed to the rupture having a stronger influence on wall tension than aneurysm size. Therefore, while larger aneurysms theoretically should show more enhancement due to higher tension [ 15 ], the rupture itself appears to be a more critical factor influencing wall tension and subsequent enhancement. The following limitations of this retrospective study have to be considered: First, the cohort size, consisting of 31 patients, may limit the generalizability of our results. Then, the study's gender distribution was notably imbalanced, with a significantly higher number of female participants (28) compared to male (3). Additionally, only one post-treatment imaging time point was available per patient, precluding any longitudinal assessment of wall enhancement dynamics. Although follow-up MRI was generally performed at approximately six months post-treatment, slight variation in timing may have influenced individual enhancement values. Moreover, the absence of earlier or serial imaging limits the ability to assess the temporal progression of aneurysm wall changes. A subset of patients underwent stent-assisted coiling. Since only the aneurysm wall was analyzed, a direct influence of the stent on measured signal intensities is unlikely, but heterogeneity of treatment cannot be entirely excluded as a potential confounder. Furthermore, the study did not account for the potential influence of the time interval between the occurrence of bleeding and follow-up controls on wall enhancement, which may have affected our findings. In the retrospective dataset analyzed, no native (pre-contrast) black-blood sequence was available. Therefore, we cannot entirely exclude the possibility that some of the observed hyperintensities may reflect preexisting T1 shortening due to thrombus or hemosiderin deposits rather than true contrast enhancement. However, as follow-up imaging was performed approximately six months after treatment in all cases, it is unlikely that early subacute blood components significantly contributed to the signal. Additionally, since all patients underwent identical imaging protocols and were analyzed using standardized ROI placement, the comparison between SAH and non-SAH cohorts remains internally valid. Visual assessments also showed peripheral enhancement patterns, supporting the interpretation as contrast agent uptake in the aneurysm wall. Finally, our analysis using maximum and mean values to reduce susceptibility artifacts faces limitations. Despite selecting maximum values to lessen coil-related distortions, concerns of deriving maxima from non-wall-bound areas were unfounded, as visual assessments showed enhancements mainly at the periphery. However, our ROI measurement, covering the entire aneurysm, might still introduce artifacts not fully mitigated by ROI placement. This method was chosen to promote reproducibility and standardization among patients. Measuring only the enhancing rim of the aneurysm wall would cause significant variability between readers and reduce consistency, particularly in small or irregularly shaped aneurysms. ROI measurements were performed in each slice containing the aneurysm, and both mean and maximum values were recorded. To minimize the impact of signal loss due to susceptibility artifacts from the coil material, we focused on maximum signal intensities. Since coil-related artifacts typically cause signal attenuation rather than artificial signal increase, the maximum value was considered a robust metric for identifying true enhancement. CONCLUSIONS Significant differences in contrast enhancement on black-blood MR sequences are observed between ruptured and unruptured aneurysms following endovascular treatment. Lower signal intensity in ruptured aneurysms may reflect resolution of stress-related inflammatory changes in the aneurysm wall. Wall tension appears to be a key driver of such stress responses in unruptured aneurysms and may diminish after rupture. Declarations Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Competing Interests: The authors have no relevant financial or non-financial interests to declare. Ethics approval: This retrospective study was approved by the institutional review board of the University Hospital Bonn. Consent to participate / publish: The need for informed consent was waived due to the retrospective design of the study. Author Contribution A-H..S. and E.H. wrote the main manuscript text A.S. and A-H.S. prepared figures 1-5.All authors reviewed the manuscript References Adamou A, Alexandrou M, Roth C, Dorn F, Vajkoczy P, Krischek B (2021) Endovascular treatment of intracranial aneurysms. Life (Basel) 11(4):335. 10.3390/life11040335 Connolly ES, Rabinstein AA, Carhuapoma JR et al (2012) Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/ American Stroke Association. Stroke 43(6):1711–1737. 10.1161/STR.0b013e3182587839 Corrêa DG, Cadete RA, da Hygino Cruz LC (2018) Vessel wall enhancement in treated unruptured aneurysms. AJNR Am J Neuroradiol 39(7):E129–E130. 10.3174/ajnr.A5843 Darsaut TE, Findlay JM, Magro E et al (2017) Surgical clipping or endovascular coiling for unruptured intracranial aneurysms: a pragmatic randomised trial. J Neurol Neurosurg Psychiatry 88(8):663–668. 10.1136/jnnp-2016-315433 Dinia L, Vert C, Gramegna LL et al (2023) Wall enhancement as a biomarker of intracranial aneurysm instability: a histo-radiological study. Acta Neurochir 165:2783–2791. 10.1007/s00701-023-05739-8 Edjlali M, Gentric JC, Régent-Rodriguez C, Trystram D, Hassen WB, Naggara O (2014) Does aneurysmal wall enhancement on vessel wall MRI help to distinguish stable from unstable intracranial aneurysms? Stroke 45(12):3704–3706. 10.1161/STROKEAHA.114.006626 Endo H, Mori N, Mugikura S et al (2022) Quantitative assessment of microstructural evolution of intracranial aneurysm wall by vessel wall imaging. Neuroradiology 64(12):1343–1350. 10.1007/s00234-021-02877-7 Etminan N, Brown RD, Beseoglu K et al (2015) The unruptured intracranial aneurysm treatment score: a multidisciplinary consensus. Neurology 85(10):881–889. 10.1212/WNL.0000000000001891 Frösen J, Tulamo R, Paetau A et al (2012) Saccular intracranial aneurysm: pathology and mechanisms. Acta Neuropathol 123(6):773–786. 10.1007/s00401-011-0939-3 Hara T, Matsushige T, Yoshiyama M et al (2023) Association of circumferential aneurysm wall enhancement with recurrence after coiling of unruptured intracranial aneurysms: a preliminary vessel wall imaging study. J Neurosurg 138(1):147–153. 10.3171/2022.4.JNS22421 Hu P, Yang Q, Wang DD, Guan SC, Xu Y, Lou X (2016) Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm. Neuroradiology 58(10):979–985. 10.1007/s00234-016-1729-3 Larsen N, Flüh C, Saalfeld S et al (2020) Multimodal validation of focal enhancement in intracranial aneurysms as a surrogate marker for aneurysm instability. Neuroradiology 62(12):1627–1635. 10.1007/s00234-020-02498-6 Larsen N, von der Brelie C, Trick D, Riedel C, Lindner T, Matschke J (2018) Vessel wall enhancement in unruptured intracranial aneurysms: an indicator for higher risk of rupture? High-resolution MR imaging and correlated histologic findings. AJNR Am J Neuroradiol 39(9):1617–1621. 10.3174/ajnr.A5731 Li MH, Chen SW, Li YD, Fang C, Xu J, Li Y (2013) Prevalence of unruptured cerebral aneurysms in Chinese adults aged 35 to 75 years. Ann Intern Med 159(8):514. 10.7326/0003-4819-159-8-201310150-00004 Lv N, Karmonik C, Chen S et al (2020) Wall enhancement, hemodynamics, and morphology in unruptured intracranial aneurysms with high rupture risk. Transl Stroke Res 11(5):882–889. 10.1007/s12975-020-00782-4 Mandell DM, Mossa-Basha M, Qiao Y et al (2017) Intracranial vessel wall MRI: principles and expert consensus recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 38(2):218–229. 10.3174/ajnr.A4893 Medical Advisory Secretariat (2006) Coil embolization for intracranial aneurysms: an evidence-based analysis. Ont Health Technol Assess Ser 6(6):1–114 Morita A, Kirino T, Hashi K et al (2012) The natural course of unruptured cerebral aneurysms in a Japanese cohort. N Engl J Med 366(26):2474–2482. 10.1056/NEJMoa1113260 Petr O, Brinjikji W, Cloft HJ, Kallmes DF (2016) Current trends and results of endovascular treatment of unruptured intracranial aneurysms at a single institution in the flow-diverter era. AJNR Am J Neuroradiol 37(6):1106–1113. 10.3174/ajnr.A4699 Sanchez S, Miller JM, Galloy A, Nino M, Ojeda D, Sagues E, Dier C, Gudino A, Jaramillo R, Samaniego EA (2025) Comprehensive morphomechanical and wall enhancement analysis of intracranial aneurysms. Eur Radiol 35:5027–5036. 10.1007/s00330-025-11417-3 Steiner T, Juvela S, Unterberg A et al (2013) European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage. Cerebrovasc Dis 35(2):93–112. 10.1159/000346087 Vlak MHM, Algra A, Brandenburg R, Rinkel GJE (2011) Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis. Lancet Neurol 10(7):626–636. 10.1016/S1474-4422(11)70109-0 Wallace RC, Karis JP, Partovi S, Sampson D, Owens DS, Yuh WT (2007) Noninvasive imaging of treated cerebral aneurysms, part I: MR angiographic follow-up of coiled aneurysms. AJNR Am J Neuroradiol 28(5):1001–1008. 10.3174/ajnr.A0662 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7686862","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":528813701,"identity":"7b3b7a0f-9d89-48d5-867a-8846b94a4948","order_by":0,"name":"Arndt-Hendrik Schievelkamp","email":"","orcid":"","institution":"Rheinische Friedrich-Wilhelms-Universität Bonn","correspondingAuthor":false,"prefix":"","firstName":"Arndt-Hendrik","middleName":"","lastName":"Schievelkamp","suffix":""},{"id":528813702,"identity":"cb42e101-400b-4e96-ae23-e3ea689df1a4","order_by":1,"name":"Alexander Schnepper","email":"","orcid":"","institution":"Rheinische 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1","display":"","copyAsset":false,"role":"figure","size":1881583,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/75594dd1ab9f170e98c88a27.png"},{"id":93728696,"identity":"679c564f-cca3-45f0-9797-346a25c747dc","added_by":"auto","created_at":"2025-10-17 02:12:50","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2741540,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/fece508fa49574c7e8da4d43.png"},{"id":93728700,"identity":"dc1cc6cf-766e-4e96-ad10-52c151e7c4fa","added_by":"auto","created_at":"2025-10-17 02:12:50","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":5396451,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/c5a4caf5aac3f3cc1b25d6f2.png"},{"id":93728703,"identity":"aef8a128-0ced-4b54-b9c5-f2dbccc51627","added_by":"auto","created_at":"2025-10-17 02:12:50","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":5531568,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/ffa4e24de99ead2472eadbd8.png"},{"id":93728712,"identity":"8069b8a2-9971-4508-9623-b22486601c34","added_by":"auto","created_at":"2025-10-17 02:12:50","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":83766,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/7ad7d29b12b25286859ce103.png"},{"id":93733321,"identity":"79a04c79-9e64-4c8e-b5fe-c71b700bdda2","added_by":"auto","created_at":"2025-10-17 02:44:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11928899,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7686862/v1/fd1a8e8a-f474-4b36-b829-cec74f874cd7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe prevalence of intracranial aneurysms is estimated to be 2% to 3% among the adult population [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The main risk of intradural aneurysms is aneurysm rupture, leading to subarachnoid hemorrhage (SAH), which is associated with significant mortality and morbidity in the affected patients.\u003c/p\u003e\u003cp\u003eFor both ruptured and unruptured intracranial aneurysms, established treatment options include endovascular approaches \u0026ndash; such as coil embolization, which remains the most commonly used technique, as well as stent- and flow-diverter-assisted methods \u0026ndash; and surgical clipping [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Ruptured aneurysms should be promptly managed with either clipping or endovascular treatment in order to prevent re-bleeding [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. For unruptured aneurysms, treatment options may include conservative therapy, endovascular treatment, or clipping depending on the size, configuration and localization of the aneurysm [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. To evaluate the need for interventional therapy in incidental and unruptured aneurysms, the risk assessment regarding an aneurysm rupture is a crucial factor. Despite various interim analyses of large intervention studies, this risk assessment remains controversial.\u003c/p\u003e\u003cp\u003eHigh-resolution vessel wall MR imaging is discussed as a possible tool for characterizing and identifying cerebral aneurysms at increased risk of rupture [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. However, only few studies have been published regarding aneurysm wall enhancement following coil embolization [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis study aimed to identify factors influencing aneurysm wall enhancement after coil embolization by comparing ruptured aneurysms in patients with SAH to incidentally detected unruptured aneurysms. The null hypothesis posits that there are no significant differences in aneurysm wall enhancement post-coil embolization between patients with and without SAH. To account for possible confounding variables, secondary hypotheses examined whether coil packing density or aneurysm size affected wall enhancement. Furthermore, the correlation between the amount of foreign material and wall enhancement was assessed.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eThis retrospective cross-sectional single-center study was approved by the institutional review board. Patients with an incidentally detected intracranial aneurysm without symptoms and patients with subarachnoid hemorrhage (SAH), confirmed by clinical presentation and cranial computed tomography (CT), who underwent coil embolization treatment (in 10 cases stent-assisted) and were routinely followed up with digital subtraction angiography (DSA) and magnetic resonance imaging (MRI) were examined. The cohort included in this study was based on a predefined dataset from 2015 to 2016, established as part of a systematic follow-up program at our institution. All follow-up examinations (DSA and MRI) of patients with an intracranial aneurysm treated by coil embolization during this period have been included in this study. Follow-up MRI and DSA were performed approximately six months after coil embolization as part of the routine institutional protocol. Cases from later years could not be included due to changes in clinical workflows and imaging protocols, which affected data completeness and standardization.\u003c/p\u003e\n\u003cp\u003eThe only exclusion criteria were insufficient MR image quality due to severe artifacts from patient movement or the proximity to bony structures (skull base). To analyze our hypothesis, patients with and without SAH were divided into two different groups. All digital subtraction angiographies and MRI examinations were performed at our department\u0026apos;s facility using a Philips Allura Xper FD20 for angiographies and a 3 Tesla scanner (Philips Achieva) for MRI. The MRI sequences obtained are shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eList of the sequences obtained.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSequence\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOrientation\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTR [ms]\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTE [ms]\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eFlip Angle \u0026deg;\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSlice Thickness\u003c/p\u003e\n \u003cp\u003e(mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVoxel Resolution (mm\u0026sup3;)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT2W TSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3277\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSingle-shot Diffusion-weighted Imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2548\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime-of-Flight Angiography\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3,7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT2W TSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCoronar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4137\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT1W IR TSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2,5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eT1W TSE -/+ GBCA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e624\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13,4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBlack Blood T1W IR TSE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAxial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2263\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0,43\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3D T1W Fast-SE\u0026thinsp;+\u0026thinsp;GBCA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSagittal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8,31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3,8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\"\u003e* W: weighted; TSE: Turbo Spin Echo; IR: Inversion Recovery; GBCA: Gadolinium-based Contrast Agent\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eThe contrast-enhanced black-blood sequence was consistently acquired at a standardized time point following intravenous contrast agent administration as part of the institutional protocol. The measurements were performed by a graduate student after extensive training and under close supervision by an experienced neuroradiologist.\u003c/p\u003e\n\u003cp\u003eAneurysm wall enhancement was assessed using ROI measurements of signal intensities (SI) applied over the entire aneurysm; in each slice depicting the aneurysm in the black-blood T1-weighted sequence following intravenous administration of a Gadolinium-containing contrast agent (Fig.\u0026nbsp;1), focusing on maximal values to mitigate potential artifacts from coil material-induced signal loss.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eAdditionally, visual evaluation using a template was conducted to complement the quantitative analysis. This was based on a 3-point Likert scale: 1\u0026thinsp;=\u0026thinsp;no or minimal wall enhancement, 2\u0026thinsp;=\u0026thinsp;moderate enhancement, 3\u0026thinsp;=\u0026thinsp;strong enhancement. Representative examples are shown in FIG. 2.\u003c/p\u003e\n\u003cp\u003eCoil density was estimated in the planar images of DSA using ROI measurement (FIG. 3) and assessed visually using a template (FIG. 4).\u003c/p\u003e\n\u003cp\u003eThe visual scale was developed in-house for this study and enabled standardized categorization of coil packing into low, medium, and high density.\u003c/p\u003e\n\u003cp\u003eStatistical evaluation was performed using the two-sided Student\u0026apos;s t-test to compare parameters between patients with and without SAH. Results with a p-value of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered significant. Linear regression was used to assess the potential impact of coil material packing density and aneurysm size on ROI measurement results.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe exclusion of examinations due to insufficient image quality led to the selection of 31 out of a total of 51 patients \u0026ndash; consisting of 28 females and three males \u0026ndash; with an average age of 56 (ranging from 39 to 79 years old). Among these participants, 14 were diagnosed with SAH. Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e provides a comprehensive overview of the patient group, including cases of stent-assisted coiling.\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eOverview of the test subjects and the aneurysms included in the evaluation.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSAH (N=)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNo SAH (N=)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTotal (N=)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePatients treated with coil embolization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStent-supported coil treatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAdditional devices (e.g.; stent-in-stent)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAneurysm largest diameter (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt; 4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u0026ndash;7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u0026ndash;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGroup \u0026quot;small aneurysms\u0026quot; (\u0026lt;\u0026thinsp;7 mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGroup \u0026quot;large aneurysms\u0026quot; (\u0026gt;\u0026thinsp;7 mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003eThe study found no significant discrepancy in the size of aneurysms between those with and without SAH.\u003c/p\u003e\n\u003cp\u003eEnhancement of aneurysm wall\u003c/p\u003e\n\u003cp\u003eVisual assessment:\u003c/p\u003e\n\u003cp\u003eVisual assessment revealed that aneurysms in patients without SAH exhibited a more pronounced increase in signal intensity of the aneurysm wall in contrast-enhanced T1-weighted black-blood sequences compared to those in patients with SAH (p\u0026thinsp;=\u0026thinsp;0.02).\u003c/p\u003e\n\u003cp\u003eROI measurements:\u003c/p\u003e\n\u003cp\u003eROI measurements revealed higher maximal SI values in the aneurysms of patients without SAH compared to those with SAH (SAH: 813 SI vs. no SAH: 1151 SI, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). A comparison of the mean values of the SI in the ROI measurements in the contrast-enhanced black blood sequence is shown in Fig.\u0026nbsp;5.\u003c/p\u003e\n\u003cp\u003eThe pertinent raw data is presented in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eMaximal Signal Intensity (Max SI) values of the coil-treated aneurysms in the black blood T1-weighted sequence (BB-T1W) in patients with and without SAH\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAneurysm Number\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSAH yes+/no-\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eLocalization\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSize in mm\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMax SI BB-T1W\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1051\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e461\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1190\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e717\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1127\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e384\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVertebral artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e201\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e778\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1089\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1338\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e826\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1102\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e544\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e535\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2135\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e939\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft superior cerebellar artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1159\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1256\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e491\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e985\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e914\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight middle cerebral artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1256\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1193\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1694\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1027\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight posterior communicating artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1421\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLeft internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e976\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight posterior inferior cerebellar artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1094\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBasilar apex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1162\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRight internal carotid artery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e881\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eLarger aneurysms exhibited higher signal intensities in ROI measurements compared to smaller ones (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01), a distinction not reflected in visual evaluations. However, linear regression analysis showed that aneurysm size did not have a significant impact on the differences in ROI measurements in the black-blood sequence between patients with and without SAH.\u003c/p\u003e\n\u003cp\u003eCoil packing:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNo significant variance in coil packing density in relation to the size of the aneurysm was found, nor was there a discernible difference in coil packing density when comparing patients with and without SAH. Linear regression analysis evaluating the effects of coil packing density on wall enhancement revealed insignificant influence.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis study compares aneurysm wall enhancement in patients who underwent coil embolization and were followed-up with DSA and MRI, who had either incidentally detected intracranial aneurysms without symptoms or who had undergone SAH. We found that aneurysms in patients without SAH showed more pronounced wall enhancement in both ROI measurements and visual assessments. While coil density showed no significant impact on aneurysm wall enhancement, notable differences in wall enhancement between patients with and without SAH indicate that aneurysm rupture and/or the presence of SAH influences post-embolization wall behavior.\u003c/p\u003e\u003cp\u003eIncreased accumulation of contrast agent in the aneurysm wall following endovascular coiling has been described [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. It has been hypothesized that post-interventional remodeling processes, including the formation of a peripheral thrombosis in the aneurysm sac, may be responsible for this phenomenon [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Increasing vascularization of the aneurysm wall with ingrowth of vascularized tissue into the coil material has been described [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eHistological analysis has revealed an increase in vascularization of the aneurysm wall, accompanied by the ingrowth of vascularized tissue into the coil material [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Additionally, an elevated inflammatory reaction within the aneurysm wall, characterized by an influx of inflammatory cells, has been observed [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. These findings are in line with recent histo-radiological evidence demonstrating that aneurysm wall enhancement strongly correlates with inflammatory cell infiltration, neovascularization, and wall degeneration, supporting its role as an independent imaging marker of aneurysm instability [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOur findings indicate accumulation of contrast agent within the aneurysm wall following coiling treatment. Aneurysm wall enhancement was significantly lower in patients presenting with SAH compared to those with incidentally detected aneurysms. One potential explanation is a reduction in wall tension when the aneurysm ruptures during SAH. Recent studies show that aneurysm wall enhancement is linked to higher wall tension and unfavorable hemodynamic conditions, regardless of aneurysm size [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In line with this, several clinical studies have found that pronounced aneurysm wall enhancement is associated with aneurysm instability, such as rupture risk and growth [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The result of our study underlines that the wall tension or the decrease thereof has a decisive influence on the enhancement behavior of aneurysms. Histological analysis indicated that, following rupture, the aneurysm wall undergoes remodeling, which is demonstrated by increased scar tissue formation, reduced inflammatory response, and decreased vascularization of the aneurysm wall [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The increased tissue stress with an inflammatory response, caused by increased tension in the wall of unruptured aneurysms compared to ruptured aneurysms, may be a potential explanation for the increased aneurysm wall enhancement observed [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe study reported that aneurysm size did not differ significantly between individuals with SAH and those without. As mentioned previously, larger aneurysms exhibited higher signal intensities in ROI measurements compared to smaller ones, a distinction not mirrored in visual evaluations. An explanation for this could be that larger aneurysms have higher wall tension, which would be expected to correlate with increased enhancement. Nonetheless, our regression analysis did not confirm a significant impact of aneurysm size on the differences in ROI measurements between patients with and without SAH. A higher accumulation of contrast agent within the aneurysm wall has been linked to an elevated risk of rupture [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The lack of a significant finding in our study might be attributed to the rupture having a stronger influence on wall tension than aneurysm size. Therefore, while larger aneurysms theoretically should show more enhancement due to higher tension [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], the rupture itself appears to be a more critical factor influencing wall tension and subsequent enhancement.\u003c/p\u003e\u003cp\u003eThe following limitations of this retrospective study have to be considered: First, the cohort size, consisting of 31 patients, may limit the generalizability of our results. Then, the study's gender distribution was notably imbalanced, with a significantly higher number of female participants (28) compared to male (3). Additionally, only one post-treatment imaging time point was available per patient, precluding any longitudinal assessment of wall enhancement dynamics. Although follow-up MRI was generally performed at approximately six months post-treatment, slight variation in timing may have influenced individual enhancement values. Moreover, the absence of earlier or serial imaging limits the ability to assess the temporal progression of aneurysm wall changes. A subset of patients underwent stent-assisted coiling. Since only the aneurysm wall was analyzed, a direct influence of the stent on measured signal intensities is unlikely, but heterogeneity of treatment cannot be entirely excluded as a potential confounder. Furthermore, the study did not account for the potential influence of the time interval between the occurrence of bleeding and follow-up controls on wall enhancement, which may have affected our findings. In the retrospective dataset analyzed, no native (pre-contrast) black-blood sequence was available. Therefore, we cannot entirely exclude the possibility that some of the observed hyperintensities may reflect preexisting T1 shortening due to thrombus or hemosiderin deposits rather than true contrast enhancement. However, as follow-up imaging was performed approximately six months after treatment in all cases, it is unlikely that early subacute blood components significantly contributed to the signal. Additionally, since all patients underwent identical imaging protocols and were analyzed using standardized ROI placement, the comparison between SAH and non-SAH cohorts remains internally valid. Visual assessments also showed peripheral enhancement patterns, supporting the interpretation as contrast agent uptake in the aneurysm wall. Finally, our analysis using maximum and mean values to reduce susceptibility artifacts faces limitations. Despite selecting maximum values to lessen coil-related distortions, concerns of deriving maxima from non-wall-bound areas were unfounded, as visual assessments showed enhancements mainly at the periphery. However, our ROI measurement, covering the entire aneurysm, might still introduce artifacts not fully mitigated by ROI placement. This method was chosen to promote reproducibility and standardization among patients. Measuring only the enhancing rim of the aneurysm wall would cause significant variability between readers and reduce consistency, particularly in small or irregularly shaped aneurysms. ROI measurements were performed in each slice containing the aneurysm, and both mean and maximum values were recorded. To minimize the impact of signal loss due to susceptibility artifacts from the coil material, we focused on maximum signal intensities. Since coil-related artifacts typically cause signal attenuation rather than artificial signal increase, the maximum value was considered a robust metric for identifying true enhancement.\u003c/p\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eSignificant differences in contrast enhancement on black-blood MR sequences are observed between ruptured and unruptured aneurysms following endovascular treatment. Lower signal intensity in ruptured aneurysms may reflect resolution of stress-related inflammatory changes in the aneurysm wall. Wall tension appears to be a key driver of such stress responses in unruptured aneurysms and may diminish after rupture.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\u003cp\u003eCompeting Interests: The authors have no relevant financial or non-financial interests to declare.\u003c/p\u003e\u003cp\u003e Ethics approval: This retrospective study was approved by the institutional review board of the University Hospital Bonn.\u003c/p\u003e\u003cp\u003e Consent to participate / publish: The need for informed consent was waived due to the retrospective design of the study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eA-H..S. and E.H. wrote the main manuscript text A.S. and A-H.S. prepared figures 1-5.All authors reviewed the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAdamou A, Alexandrou M, Roth C, Dorn F, Vajkoczy P, Krischek B (2021) Endovascular treatment of intracranial aneurysms. Life (Basel) 11(4):335. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/life11040335\u003c/span\u003e\u003cspan address=\"10.3390/life11040335\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eConnolly ES, Rabinstein AA, Carhuapoma JR et al (2012) Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/ American Stroke Association. Stroke 43(6):1711\u0026ndash;1737. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1161/STR.0b013e3182587839\u003c/span\u003e\u003cspan address=\"10.1161/STR.0b013e3182587839\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCorr\u0026ecirc;a DG, Cadete RA, da Hygino Cruz LC (2018) Vessel wall enhancement in treated unruptured aneurysms. AJNR Am J Neuroradiol 39(7):E129\u0026ndash;E130. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3174/ajnr.A5843\u003c/span\u003e\u003cspan address=\"10.3174/ajnr.A5843\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDarsaut TE, Findlay JM, Magro E et al (2017) Surgical clipping or endovascular coiling for unruptured intracranial aneurysms: a pragmatic randomised trial. J Neurol Neurosurg Psychiatry 88(8):663\u0026ndash;668. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1136/jnnp-2016-315433\u003c/span\u003e\u003cspan address=\"10.1136/jnnp-2016-315433\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDinia L, Vert C, Gramegna LL et al (2023) Wall enhancement as a biomarker of intracranial aneurysm instability: a histo-radiological study. Acta Neurochir 165:2783\u0026ndash;2791. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00701-023-05739-8\u003c/span\u003e\u003cspan address=\"10.1007/s00701-023-05739-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEdjlali M, Gentric JC, R\u0026eacute;gent-Rodriguez C, Trystram D, Hassen WB, Naggara O (2014) Does aneurysmal wall enhancement on vessel wall MRI help to distinguish stable from unstable intracranial aneurysms? Stroke 45(12):3704\u0026ndash;3706. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1161/STROKEAHA.114.006626\u003c/span\u003e\u003cspan address=\"10.1161/STROKEAHA.114.006626\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEndo H, Mori N, Mugikura S et al (2022) Quantitative assessment of microstructural evolution of intracranial aneurysm wall by vessel wall imaging. Neuroradiology 64(12):1343\u0026ndash;1350. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00234-021-02877-7\u003c/span\u003e\u003cspan address=\"10.1007/s00234-021-02877-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEtminan N, Brown RD, Beseoglu K et al (2015) The unruptured intracranial aneurysm treatment score: a multidisciplinary consensus. Neurology 85(10):881\u0026ndash;889. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1212/WNL.0000000000001891\u003c/span\u003e\u003cspan address=\"10.1212/WNL.0000000000001891\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFr\u0026ouml;sen J, Tulamo R, Paetau A et al (2012) Saccular intracranial aneurysm: pathology and mechanisms. Acta Neuropathol 123(6):773\u0026ndash;786. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00401-011-0939-3\u003c/span\u003e\u003cspan address=\"10.1007/s00401-011-0939-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHara T, Matsushige T, Yoshiyama M et al (2023) Association of circumferential aneurysm wall enhancement with recurrence after coiling of unruptured intracranial aneurysms: a preliminary vessel wall imaging study. J Neurosurg 138(1):147\u0026ndash;153. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2022.4.JNS22421\u003c/span\u003e\u003cspan address=\"10.3171/2022.4.JNS22421\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHu P, Yang Q, Wang DD, Guan SC, Xu Y, Lou X (2016) Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm. Neuroradiology 58(10):979\u0026ndash;985. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00234-016-1729-3\u003c/span\u003e\u003cspan address=\"10.1007/s00234-016-1729-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLarsen N, Fl\u0026uuml;h C, Saalfeld S et al (2020) Multimodal validation of focal enhancement in intracranial aneurysms as a surrogate marker for aneurysm instability. Neuroradiology 62(12):1627\u0026ndash;1635. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00234-020-02498-6\u003c/span\u003e\u003cspan address=\"10.1007/s00234-020-02498-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLarsen N, von der Brelie C, Trick D, Riedel C, Lindner T, Matschke J (2018) Vessel wall enhancement in unruptured intracranial aneurysms: an indicator for higher risk of rupture? High-resolution MR imaging and correlated histologic findings. AJNR Am J Neuroradiol 39(9):1617\u0026ndash;1621. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3174/ajnr.A5731\u003c/span\u003e\u003cspan address=\"10.3174/ajnr.A5731\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLi MH, Chen SW, Li YD, Fang C, Xu J, Li Y (2013) Prevalence of unruptured cerebral aneurysms in Chinese adults aged 35 to 75 years. Ann Intern Med 159(8):514. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.7326/0003-4819-159-8-201310150-00004\u003c/span\u003e\u003cspan address=\"10.7326/0003-4819-159-8-201310150-00004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLv N, Karmonik C, Chen S et al (2020) Wall enhancement, hemodynamics, and morphology in unruptured intracranial aneurysms with high rupture risk. Transl Stroke Res 11(5):882\u0026ndash;889. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s12975-020-00782-4\u003c/span\u003e\u003cspan address=\"10.1007/s12975-020-00782-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMandell DM, Mossa-Basha M, Qiao Y et al (2017) Intracranial vessel wall MRI: principles and expert consensus recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 38(2):218\u0026ndash;229. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3174/ajnr.A4893\u003c/span\u003e\u003cspan address=\"10.3174/ajnr.A4893\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMedical Advisory Secretariat (2006) Coil embolization for intracranial aneurysms: an evidence-based analysis. Ont Health Technol Assess Ser 6(6):1\u0026ndash;114\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMorita A, Kirino T, Hashi K et al (2012) The natural course of unruptured cerebral aneurysms in a Japanese cohort. N Engl J Med 366(26):2474\u0026ndash;2482. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1056/NEJMoa1113260\u003c/span\u003e\u003cspan address=\"10.1056/NEJMoa1113260\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePetr O, Brinjikji W, Cloft HJ, Kallmes DF (2016) Current trends and results of endovascular treatment of unruptured intracranial aneurysms at a single institution in the flow-diverter era. AJNR Am J Neuroradiol 37(6):1106\u0026ndash;1113. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3174/ajnr.A4699\u003c/span\u003e\u003cspan address=\"10.3174/ajnr.A4699\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSanchez S, Miller JM, Galloy A, Nino M, Ojeda D, Sagues E, Dier C, Gudino A, Jaramillo R, Samaniego EA (2025) Comprehensive morphomechanical and wall enhancement analysis of intracranial aneurysms. Eur Radiol 35:5027\u0026ndash;5036. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00330-025-11417-3\u003c/span\u003e\u003cspan address=\"10.1007/s00330-025-11417-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSteiner T, Juvela S, Unterberg A et al (2013) European Stroke Organization guidelines for the management of intracranial aneurysms and subarachnoid haemorrhage. Cerebrovasc Dis 35(2):93\u0026ndash;112. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1159/000346087\u003c/span\u003e\u003cspan address=\"10.1159/000346087\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVlak MHM, Algra A, Brandenburg R, Rinkel GJE (2011) Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis. Lancet Neurol 10(7):626\u0026ndash;636. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1474-4422(11)70109-0\u003c/span\u003e\u003cspan address=\"10.1016/S1474-4422(11)70109-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWallace RC, Karis JP, Partovi S, Sampson D, Owens DS, Yuh WT (2007) Noninvasive imaging of treated cerebral aneurysms, part I: MR angiographic follow-up of coiled aneurysms. AJNR Am J Neuroradiol 28(5):1001\u0026ndash;1008. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3174/ajnr.A0662\u003c/span\u003e\u003cspan address=\"10.3174/ajnr.A0662\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Intracranial aneurysm, wall enhancement, coil embolization, subarachnoid hemorrhage, black-blood MRI","lastPublishedDoi":"10.21203/rs.3.rs-7686862/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7686862/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eThis study aimed to compare aneurysm wall enhancement post-coil embolization between patients with and without subarachnoid hemorrhage (SAH). We hypothesized that ruptured aneurysms in SAH patients exhibit different enhancement patterns compared to incidentally found unruptured aneurysms. Potential confounding factors for wall enhancement, such as coil packing density and aneurysm size, were also assessed.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis retrospective cross-sectional single-center study included patients who underwent coil embolization for intracranial aneurysms. Subsequently, these patients were monitored with digital subtraction angiography and magnetic resonance imaging, which included a \"black blood\" contrast-enhanced sequence. Data were analyzed using ROI signal intensities (SI) and visual evaluation. Quantitative and visual assessments of aneurysm wall enhancement were compared between patients with and without SAH using the two-sided Student's t-test. In addition, linear regression was performed to explore the effects of coil density and aneurysm size on wall enhancement.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eAmong the 31 patients studied, those with unruptured aneurysm without SAH showed higher wall signal intensities after embolization compared to SAH patients with ruptured and coil-embolized aneurysms (Visual assessment: p\u0026thinsp;=\u0026thinsp;0.02; ROI measurements: SAH: 813 SI vs. no SAH: 1151 SI, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01). No significant correlation was found between coil packing density and wall enhancement, nor was there a significant impact of aneurysm size on the enhancement in visual assessment.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eAneurysm wall enhancement after coil embolization differs significantly between patients with and without SAH, suggesting that aneurysm rupture changes the characteristics of the aneurysm wall. Coil density and aneurysm size appear to have less influence on wall enhancement.\u003c/p\u003e","manuscriptTitle":"Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-17 02:12:45","doi":"10.21203/rs.3.rs-7686862/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b778d942-4281-4db0-9165-f9b2b1a1042f","owner":[],"postedDate":"October 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-17T02:12:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-17 02:12:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7686862","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7686862","identity":"rs-7686862","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}