scholarly journals Analysis of Cerebral Aneurysm Wall Tension and Enhancement Using Finite Element Analysis and High-Resolution Vessel Wall Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Adam E. Galloy ◽  
Ashrita Raghuram ◽  
Marco A. Nino ◽  
Alberto Varon Miller ◽  
Ryan Sabotin ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Resolution ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Vessel Wall Imaging ◽  
Wall Tension ◽  
Element Analysis ◽  
Aneurysm Wall ◽  
Wall Imaging

Biomechanical computational simulation of intracranial aneurysms has become a promising method for predicting features of instability leading to aneurysm growth and rupture. Hemodynamic analysis of aneurysm behavior has helped investigate the complex relationship between features of aneurysm shape, morphology, flow patterns, and the proliferation or degradation of the aneurysm wall. Finite element analysis paired with high-resolution vessel wall imaging can provide more insight into how exactly aneurysm morphology relates to wall behavior, and whether wall enhancement can describe this phenomenon. In a retrospective analysis of 23 unruptured aneurysms, finite element analysis was conducted using an isotropic, homogenous third order polynomial material model. Aneurysm wall enhancement was quantified on 2D multiplanar views, with 14 aneurysms classified as enhancing (CRstalk≥0.6) and nine classified as non-enhancing. Enhancing aneurysms had a significantly higher 95th percentile wall tension (μ = 0.77 N/cm) compared to non-enhancing aneurysms (μ = 0.42 N/cm, p < 0.001). Wall enhancement remained a significant predictor of wall tension while accounting for the effects of aneurysm size (p = 0.046). In a qualitative comparison, low wall tension areas concentrated around aneurysm blebs. Aneurysms with irregular morphologies may show increased areas of low wall tension. The biological implications of finite element analysis in intracranial aneurysms are still unclear but may provide further insights into the complex process of bleb formation and aneurysm rupture.

scholarly journals Circumferential wall enhancement in evolving intracranial aneurysms on magnetic resonance vessel wall imaging

2019 ◽  
Vol 131 (4) ◽  
pp. 1262-1268 ◽  
Author(s):  
Shunsuke Omodaka ◽  
Hidenori Endo ◽  
Kuniyasu Niizuma ◽  
Miki Fujimura ◽  
Takashi Inoue ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Contrast Ratio ◽  
Multivariable Analysis ◽  
Vessel Wall Imaging ◽  
Fast Spin Echo ◽  
Unruptured Aneurysms ◽  
Ruptured Aneurysms ◽  
Aneurysm Wall ◽  
Wall Imaging

OBJECTIVERecent MR vessel wall imaging studies have indicated intracranial aneurysms in the active state could show circumferential enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in unruptured aneurysms at the evolving state (i.e., growing or symptomatic) has not been studied in detail. The authors quantitatively assessed the degree of CEAW in evolving unruptured aneurysms by comparing it separately to that in stable unruptured and ruptured aneurysms.METHODSA quantitative analysis of CEAW was performed in 26 consecutive evolving aneurysms using MR vessel wall imaging. Three-dimensional T1-weighted fast spin echo sequences were obtained before and after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of CEAW. Aneurysm characteristics of evolving aneurysms were compared with those of 69 stable unruptured and 67 ruptured aneurysms.RESULTSThe CRstalk values in evolving aneurysms were significantly higher than those in stable aneurysms (0.54 vs 0.34, p < 0.0001), and lower than those in ruptured aneurysms (0.54 vs 0.83, p < 0.0002). In multivariable analysis, CRstalk remained significant when comparing evolving with stable aneurysms (odds ratio [OR] 12.23, 95% confidence interval [CI] 3.53–42.41), and with ruptured aneurysms (OR 0.083, 95% CI 0.022–0.310).CONCLUSIONSThe CEAW in evolving aneurysms was higher than those in stable aneurysms, and lower than those in ruptured aneurysms. The degree of CEAW may indicate the process leading to rupture of intracranial aneurysms, which can be useful additional information to determine an indication for surgical treatment of unruptured aneurysms.

scholarly journals Vessel wall imaging in intracranial aneurysms

2019 ◽  
Vol 11 (11) ◽  
pp. 1105-1112 ◽  
Author(s):  
Edgar A Samaniego ◽  
Jorge A Roa ◽  
David Hasan
Keyword(s):  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Vessel Wall Imaging ◽  
Current Evidence ◽  
Clinical Use ◽  
Quantitative Susceptibility Mapping ◽  
Aneurysm Wall ◽  
Brain Aneurysms ◽  
Wall Imaging

High-resolution vessel wall imaging (HR-VWI) is becoming a useful tool in the characterization and identification of unstable unruptured brain aneurysms. However, it has not been validated for clinical use. The current evidence on HR-VWI techniques for characterization of brain aneurysms is described in this review. Specific imaging approaches such as aneurysm wall contrast enhancement, MRI-quantitative susceptibility mapping, and 7T MRI are described in detail.

Conventional and high-resolution vessel wall MRI of intracranial aneurysms: current concepts and new horizons

2018 ◽  
Vol 128 (4) ◽  
pp. 969-981 ◽  
Author(s):  
Vance T. Lehman ◽  
Waleed Brinjikji ◽  
Mahmud Mossa-Basha ◽  
Giuseppe Lanzino ◽  
Alejandro A. Rabinstein ◽  
...  
Keyword(s):  
High Resolution ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Biological Behavior ◽  
Wall Structure ◽  
New Horizons ◽  
Aneurysm Wall ◽  
Resolution Imaging ◽  
Wall Imaging

Intracranial aneurysms are heterogeneous in histopathology and imaging appearance. The biological behavior of different types of aneurysms is now known to depend on the structure and physiology of the aneurysm wall itself in addition to intraluminal flow and other luminal features. Aneurysm wall structure and imaging markers of physiology such as aneurysm wall enhancement have been assessed in many prior investigations using conventional-resolution MRI. Recently, high-resolution vessel wall imaging (HR-VWI) techniques with MRI have been introduced. Reports of findings on high-resolution imaging have already emerged for many types of aneurysms demonstrating detailed characterization of wall enhancement, thickness, and components, but many questions remain unexplored. This review discusses the key HR-VWI literature to date. Aneurysm wall findings on conventional-resolution MRI are also discussed as these may help one understand the potential utility and findings on HR-VWI for various aneurysm types. The authors have illustrated these points with several examples demonstrating both features already described in the literature and novel cases demonstrating the potential for future clinical and research applications.

Abstract WMP29: Contrast Enhancement Measurement of Unruptured Intracranial Aneurysms: A 3T High-Resolution Vessel Wall Imaging Validation Study

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Jorge A Roa ◽  
Mario Zanaty ◽  
Avery Pazour ◽  
Carlos Osorno-Cruz ◽  
Daizo Ishii ◽  
...  
Keyword(s):  
High Resolution ◽  
Contrast Enhancement ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Roc Curves ◽  
Vessel Wall Imaging ◽  
Enhancement Ratio ◽  
Post Contrast ◽  
Unruptured Intracranial Aneurysms ◽  
Wall Imaging

Background: High-resolution vessel wall imaging (HR-VWI) has emerged as a valuable tool in assessing unruptured intracranial aneurysms (UIAs). There is no standardized method to quantify contrast enhancement of the aneurysmal wall. Contrast enhancement is reflected as signal intensity (SI) at the time of objective quantification. This study compares all the existing methods to objectively quantify contrast enhancement of UIAs. Methods: 3T HR-VWI was used to prospectively image patients with UIAs. Three different methods were analyzed in T1 pre- and post-contrast sequences: (1) circumferential aneurysm wall enhancement (CAWE) = mean post-contrast SI; (2) aneurysm-to-pituitary enhancement ratio (CR stalk ) = ratio of CAWE over pituitary stalk enhancement; and (3) enhancement ratio (ER) = max post-contrast SI - max pre-contrast SI/max pre-contrast SI x 100%. Known risks factors of aneurysm instability such as size ≥7mm and location in the anterior communicating (ACOM) and basilar arteries (BA) were used for analysis. Results: Forty-seven patients with 53 UIAs were included in the study. Mean age was 63.5 years, and 35 (74.5%) were women. UIAs ≥ 7mm showed significantly higher SI measurements for CAWE (273.1 vs 206.9, P =.05), CR stalk (0.49 vs 0.38, P =.006), and ER (85.7% vs 52.5%, P =.002) compared to smaller UIAs. SI was higher in UIAs located in the ACOM and BA (279.6 vs 235.7; 0.45 vs 0.44; 75.1% vs 61.3%) for CAWE, CR stalk and ER, respectively. ROC curves demonstrated sensitivity/specificity values of 0.74/0.64 for CAWE ≥ 205, 0.74/0.60 for CR stalk ≥ 0.398, and 0.71/0.73 for ER ≥ 62.1%. We found a moderately strong correlation between CAWE and CR stalk (Spearman = 0.69), CAWE and ER (Spearman = 0.52) and CR stalk and ER (Spearman = 0.47), with P <.001 in all cases. Conclusion: Three different methods: CAWE, CR stalk and ER may be used reliably to quantify SI in the wall of UIAs. Figure: ROC curves for (A) CAWE, (B) CR stalk and (C) ER.

scholarly journals Objective quantification of contrast enhancement of unruptured intracranial aneurysms: a high-resolution vessel wall imaging validation study

2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jorge A. Roa ◽  
Mario Zanaty ◽  
Carlos Osorno-Cruz ◽  
Daizo Ishii ◽  
Girish Bathla ◽  
...  
Keyword(s):  
High Resolution ◽  
Contrast Enhancement ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Pituitary Stalk ◽  
Aneurysm Wall ◽  
Unruptured Intracranial Aneurysms ◽  
The Mean ◽  
Objective Quantification ◽  
Wall Imaging

OBJECTIVEHigh-resolution vessel wall imaging (HR-VWI) has emerged as a valuable tool in assessing unruptured intracranial aneurysms (UIAs). There is no standardized method to quantify contrast enhancement of the aneurysm wall. Contrast enhancement can be objectively measured as signal intensity (SI) or subjectively adjudicated. In this study, the authors compared the different methods to quantify wall enhancement of UIAs and determined the sensitivity and specificity of each method as a surrogate of aneurysm instability. They also compared SI quantification between scanners from different manufacturers.METHODSThe University of Iowa HR-VWI Project database was analyzed. This database compiles patients with UIAs who prospectively underwent HR-VWI using a 3T MRI scanner. The mean and maximal SI values of the aneurysm wall, pituitary stalk, and genu of the corpus callosum were used to compare 3 different measurement methods: 1) aneurysm enhancement ratio AER = (SIwall post − SIwall pre)/SIwall pre; 2) aneurysm-to–pituitary stalk contrast ratio CRstalk = SIwall post/SIstalk post; and 3) aneurysm enhancement index AEI = ([SIwall post/SIbrain post] − [SIwall pre/SIbrain pre])/(SIwall pre/SIbrain pre) (where “pre” indicates precontrast images and “post” indicates postcontrast images). Size ≥ 7 mm was used as a surrogate of aneurysm instability for receiver operating characteristic (ROC) curve analysis. To determine if the objective quantification of SI varies among scanners from different manufacturers, 9 UIAs underwent the same HR-VWI protocol using a 3T General Electric (GE) scanner and a 3T Siemens scanner. Three UIAs also underwent a third scanning procedure on a unit with a different magnet strength (7T GE).RESULTSEighty patients with 102 UIAs were included in the study. The mean age was 64.5 ± 12.2 years, and 64 (80%) patients were women. UIAs ≥ 7 mm had significantly higher SIs than smaller UIAs (< 7 mm): AER = 0.82 vs 0.49, p < 0.001; CRstalk = 0.84 vs 0.61, p < 0.001; and AEI = 0.81 vs 0.48, p < 0.001. ROC curves demonstrated optimal sensitivity of 81.5% for CRstalk ≥ 0.60, 75.9% for AEI ≥ 0.50, and 74.1% for AER ≥ 0.49. Intermanufacturer correlation between 3T GE and 3T Siemens MRI scanners for CRstalk using mean and maximal SI values was excellent (Pearson coefficients > 0.80, p < 0.001). A similar correlation was identified among the 3 UIAs that underwent 7T imaging.CONCLUSIONSCRstalk using maximal SI values was the most reliable objective method to quantify enhancement of UIAs on HR-VWI. The same ratios were obtained between different manufacturers and on scans obtained using magnets of different strengths.

scholarly journals Decreased contrast enhancement on high-resolution vessel wall imaging of unruptured intracranial aneurysms in patients taking aspirin

2020 ◽  
pp. 1-7 ◽  
Author(s):  
Jorge A. Roa ◽  
Mario Zanaty ◽  
Daizo Ishii ◽  
Yongjun Lu ◽  
David K. Kung ◽  
...  
Keyword(s):  
High Resolution ◽  
Contrast Enhancement ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Vessel Wall Imaging ◽  
Pituitary Stalk ◽  
Noninvasive Method ◽  
Aneurysmal Wall ◽  
Unruptured Intracranial Aneurysms ◽  
Wall Imaging

OBJECTIVEInflammation plays an integral role in the formation, growth, and progression to rupture of unruptured intracranial aneurysms (UIAs). Animal and human studies have suggested that, due to its antiinflammatory effect, aspirin (ASA) may decrease the risks of growth and rupture of UIAs. High-resolution vessel wall imaging (HR-VWI) has emerged as a noninvasive method to assess vessel wall inflammation and UIA instability. To the authors’ knowledge, to date no studies have found a significant correlation between patient use of ASA and contrast enhancement of UIAs on HR-VWI.METHODSThe University of Iowa HR-VWI Project database was analyzed. This database is a compilation of data on patients with UIAs who prospectively underwent HR-VWI on a 3T Siemens MRI scanner. The presence of aneurysmal wall enhancement was objectively defined using the aneurysm-to–pituitary stalk contrast ratio (CRstalk). This ratio was calculated by measuring the maximal signal intensity in the aneurysmal wall and the pituitary stalk on postcontrast T1-weighted images. Data on aneurysm size, morphology, and location and patient demographics and comorbidities were collected. Use of ASA was defined as daily intake of ≥ 81 mg during the previous 6 months or longer. Univariate and multivariate logistic regression analyses were performed to determine factors independently associated with increased contrast enhancement of UIAs on HR-VWI.RESULTSIn total, 74 patients harboring 96 UIAs were included in the study. The mean patient age was 64.7 ± 12.4 years, and 60 patients (81%) were women. Multivariate analysis showed that age (OR 1.12, 95% CI 1.05–1.19), aneurysm size ≥ 7 mm (OR 21.3, 95% CI 4.88–92.8), and location in the anterior communicating, posterior communicating, and basilar arteries (OR 10.7, 95% CI 2.45–46.5) were significantly associated with increased wall enhancement on HR-VWI. On the other hand, use of ASA was significantly associated with decreased aneurysmal wall enhancement on HR-VWI (OR 0.22, 95% CI 0.06–0.83, p = 0.026).CONCLUSIONSThe study results establish a correlation between use of ASA daily for ≥ 6 months and significant decreases in wall enhancement of UIAs on HR-VWI. The findings also demonstrate that detection of wall enhancement using HR-MRI may be a valuable noninvasive method for assessing aneurysmal wall inflammation and UIA instability.

scholarly journals High-Resolution Vessel Wall Magnetic Resonance Imaging of Small Unruptured Intracranial Aneurysms

2021 ◽  
Vol 10 (2) ◽  
pp. 225
Author(s):  
Łukasz Zwarzany ◽  
Ernest Tyburski ◽  
Wojciech Poncyljusz
Keyword(s):  
Magnetic Resonance Imaging ◽  
Risk Factors ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Aneurysm Rupture ◽  
Resonance Imaging ◽  
Aneurysm Wall ◽  
Conventional Risk Factors

Background: We decided to investigate whether aneurysm wall enhancement (AWE) on high-resolution vessel wall magnetic resonance imaging (HR VW-MRI) coexists with the conventional risk factors for aneurysm rupture. Methods: We performed HR VW-MRI in 46 patients with 64 unruptured small intracranial aneurysms. Patient demographics and clinical characteristics were recorded. The PHASES score was calculated for each aneurysm. Results: Of the 64 aneurysms, 15 (23.4%) showed wall enhancement on post-contrast HR VW-MRI. Aneurysms with wall enhancement had significantly larger size (p = 0.001), higher dome-to-neck ratio (p = 0.024), and a more irregular shape (p = 0.003) than aneurysms without wall enhancement. The proportion of aneurysms with wall enhancement was significantly higher in older patients (p = 0.011), and those with a history of prior aneurysmal SAH. The mean PHASES score was significantly higher in aneurysms with wall enhancement (p < 0.000). The multivariate logistic regression analysis revealed that aneurysm irregularity and the PHASES score are independently associated with the presence of AWE. Conclusions: Aneurysm wall enhancement on HR VW-MRI coexists with the conventional risk factors for aneurysm rupture.

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