title: Quantifying Intracranial Aneurysm Wall Permeability for Risk Assessment Using Dynamic Contrast-Enhanced MRI: A Pilot Study.
abstract: OBJECTIVE
  Pathological changes in the intracranial aneurysm wall may lead to increases in its permeability; however the clinical significance of such changes has not been explored. The purpose of this pilot study was to quantify intracranial aneurysm wall permeability (K(trans), VL) to contrast agent as a measure of aneurysm rupture risk and compare these parameters against other established measures of rupture risk. We hypothesized K(trans) would be associated with intracranial aneurysm rupture risk as defined by various anatomic, imaging, and clinical risk factors.
  
  
  METHODS
  Twenty-seven unruptured intracranial aneurysms in 23 patients were imaged with dynamic contrast-enhanced MR imaging, and wall permeability parameters (K(trans), VL) were measured in regions adjacent to the aneurysm wall and along the paired control MCA by 2 blinded observers. K(trans) and VL were evaluated as markers of rupture risk by comparing them against established clinical (symptomatic lesions) and anatomic (size, location, morphology, multiplicity) risk metrics.
  
  
  RESULTS
  Interobserver agreement was strong as shown in regression analysis (R(2) > 0.84) and intraclass correlation (intraclass correlation coefficient >0.92), indicating that the K(trans) can be reliably assessed clinically. All intracranial aneurysms had a pronounced increase in wall permeability compared with the paired healthy MCA (P < .001). Regression analysis demonstrated a significant trend toward an increased K(trans) with increasing aneurysm size (P < .001). Logistic regression showed that K(trans) also predicted risk in anatomic (P = .02) and combined anatomic/clinical (P = .03) groups independent of size.
  
  
  CONCLUSIONS
  We report the first evidence of dynamic contrast-enhanced MR imaging-modeled contrast permeability in intracranial aneurysms. We found that contrast agent permeability across the aneurysm wall correlated significantly with both aneurysm size and size-independent anatomic risk factors. In addition, K(trans) was a significant and size-independent predictor of morphologically and clinically defined high-risk aneurysms.
authors: From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.) Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois.
authors: P
authors: P
authors: Vakil
authors: From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.).
authors: S A
authors: SA
authors: Ansari
authors: Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois.
authors: C G
authors: CG
authors: Cantrell
authors: Department of Neurological Surgery (C.S.E., H.H.B.), University of Texas-Southwestern, Dallas, Texas.
authors: C S
authors: CS
authors: Eddleman
authors: Department of Economics and Decision Sciences (F.H.D.), Western Illinois University, Macomb, Illinois.
authors: F H
authors: FH
authors: Dehkordi
authors: From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.).
authors: J
authors: J
authors: Vranic
authors: From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.).
authors: M C
authors: MC
authors: Hurley
authors: Department of Neurological Surgery (C.S.E., H.H.B.), University of Texas-Southwestern, Dallas, Texas.
authors: H H
authors: HH
authors: Batjer
authors: Neurosurgery (B.R.B.).
authors: B R
authors: BR
authors: Bendok
authors: From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.) Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois t-carroll@northwestern.edu.
authors: T J
authors: TJ
authors: Carroll
mesh_terms: D000328:Adult; D000368:Aged; D002199:Capillary Permeability; D003287:Contrast Media; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010865:Pilot Projects; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D003287:Contrast Media
references: Arterioscler Thromb Vasc Biol. 2012 Apr;32(4):1032-8
references: 22328774
references: Neurol Res. 2006 Jun;28(4):372-80
references: 16759441
references: Stroke. 2004 Oct;35(10):2287-93
references: 15322297
references: Lancet. 2003 Jul 12;362(9378):103-10
references: 12867109
references: J Neurointerv Surg. 2015 Jul;7(7):530-6
references: 24827066
references: J Neurosurg. 2002 Jan;96(1):52-6; discussion 58-60
references: 11794603
references: J Neurointerv Surg. 2013 May;5(3):201-6
references: 22387724
references: J Magn Reson Imaging. 2014 Jan;39(1):120-31
references: 24151067
references: Magn Reson Imaging. 1987;5(3):201-8
references: 3626789
references: J Neurosurg. 2002 Jan;96(1):3-42
references: 11794601
references: AJR Am J Roentgenol. 2002 Mar;178(3):711-6
references: 11856703
references: AJNR Am J Neuroradiol. 2006 Feb;27(2):409-17
references: 16484420
references: N Engl J Med. 2012 Sep 27;367(13):1267-8; author reply 1269
references: 23013093
references: Stroke. 2009 Mar;40(3):942-51
references: 19164781
references: Br J Radiol. 2003 Jan;76(901):39-50
references: 12595324
references: Radiology. 1986 Sep;160(3):757-61
references: 3488563
references: Radiology. 2006 Nov;241(2):459-68
references: 16966482
references: J Neurosurg. 2008 May;108(5):1052-60
references: 18447733
references: AJNR Am J Neuroradiol. 2006 May;27(5):1113-8
references: 16687554
references: Stroke. 2009 Jan;40(1):313-6
references: 18845802
references: Int J Numer Method Biomed Eng. 2012 Feb;28(2):214-28
references: 22548127
references: J Magn Reson Imaging. 2007 Oct;26(4):1106-11
references: 17896356
references: J Clin Neurosci. 2013 Aug;20(8):1110-3
references: 23673143
references: J Magn Reson Imaging. 2012 Mar;35(3):518-27
references: 22095652
references: J Magn Reson Imaging. 1999 Sep;10(3):223-32
references: 10508281