title: Relationship between aneurysm wall enhancement and conventional risk factors in patients with unruptured intracranial aneurysms: A black-blood MRI study.
abstract: OBJECTIVE
  Aneurysmal wall enhancement (AWE) has emerged as a new possible biomarker for depicting inflammation of the intracranial aneurysm (IA). However, the relationships of AWE with other risk factors are still unclear for unruptured IA. The purpose of this study was to investigate the association between AWE and other risk metrics.
  
  
  METHODS
  Forty-eight patients with unruptured saccular IAs diagnosed by digital subtraction angiography were recruited to undergo magnetic resonance (MR) black-blood imaging. AWE was evaluated using the pre- and post-contrast black-blood MR images. Univariate and multivariate logistic regression analysis was performed to investigate the association of AWE with other risk factors, including size, maximal neck width, parent vessel diameter, location, multiplicity, daughter sacs and other clinical factors. The prevalence of AWE in each ISUIA grade was reported and compared by Wilcoxon rank sum test.
  
  
  RESULTS
  In total, 61 aneurysms were detected in 48 patients. Aneurysm size was found to be an independent risk factor associated with AWE (OR 2.46 per mm increase, 95% CI 1.34-4.51; p = 0.004). Patient age was independently and inversely associated with AWE (OR 0.898 per year increase, 95% CI 0.812-0.994; p = 0.037). Higher prevalence of AWE was observed in larger aneurysms (12%, 71.4%, 100%, and 100% of ISUIA grade 1-4 IAs have AWE, respectively). Notably, 12% of small IAs (size <7 mm) exhibited AWE. The IAs with AWE had significant higher ISUIA grade than the IAs without (p < 0.001, Wilcoxon rank sum test).
  
  
  CONCLUSIONS
  The wall enhancement in contrast-enhanced black-blood MR images was independently associated with aneurysm size in unruptured IAs. However, some small unruptured aneurysms did exhibit wall enhancement, suggesting that AWE may provide additional aneurysm instability information to improve current size-based rupture risk evaluation metrics.
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, China.
authors.forename: Haikun
authors.initials: H
authors.lastname: Qi
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Aihua
authors.initials: A
authors.lastname: Liu
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Xianli
authors.initials: X
authors.lastname: Lv
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, China.
authors.forename: Xihai
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Internal Medicine, Nanyang City Center Hospital, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Lv
authors.affiliation: Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, China.
authors.forename: Huijun
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China liyouxiang@263.net.
authors.forename: Youxiang
authors.initials: Y
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: MRI; Unruptured intracranial aneurysm; aneurysmal wall enhancement; inflammation; vasa vasorum