title: Diffusion-compensated tofts model suggests contrast leakage through aneurysm wall.
abstract: OBJECTIVE
  The purpose of this study was to investigate the diffusional transport of contrast agent and its effects on kinetic modeling of dynamic contrast enhanced (DCE) images.
  
  
  METHODS
  We performed simulations of our diffusion-compensated model and compared these results to human intracranial aneurysms (IAs). We derive an easy-to-use parameterization of diffusional effects that can provide an accurate estimate of diffusion corrected contrast agent leakage rates (ktrans). Finally, we performed re-ansalysis of an existing data set to determine whether diffusion-corrected kinetic parameters improve the identification of high-risk IAs, thereby providing a new MRI-based imaging metric of IA stability based on wall integrity.
  
  
  RESULTS
  Probability distributions of simulated versus measured data show contrast leakage away from the aneurysm wall. Parameterization of diffusional effects on ktransshowed high correlation with long-chain methods in both surrounding tissue and near the aneurysm wall (r2= 0.91 and r2= 0.90, respectively). Finally, size, ktrans, and ( ktrans-kDCtrans) showed significant univariate relationships with rupture risk (P < 0.05).
  
  
  CONCLUSIONS
  We report the first evidence of diffusion-compensated permeability modeling in intracranial aneurysms and propose a parameterization of diffusional effects on ktrans. Furthermore, a comparison of measured versus simulated data suggests that contrast leakage occurs across the aneurysm wall. Magn Reson Med 78:2388-2398, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, USA.|University of Chicago, Department of Radiology, Chicago, Illinois, USA.
authors.forename: Charles G
authors.initials: CG
authors.lastname: Cantrell
authors.affiliation: University of Illinois, College of Medicine, Chicago, Illinois, USA.|Northwestern University, Department of Radiology, Evanston, Illinois, USA.
authors.forename: Parmede
authors.initials: P
authors.lastname: Vakil
authors.affiliation: Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Jeong
authors.affiliation: Northwestern University, Department of Radiology, Evanston, Illinois, USA.|Northwestern University, Departments of Neurology and Neurological Surgery, Evanston, Illinois, USA.
authors.forename: Sameer A
authors.initials: SA
authors.lastname: Ansari
authors.affiliation: University of Chicago, Department of Radiology, Chicago, Illinois, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000783:Aneurysm; D003198:Computer Simulation; D003287:Contrast Media / Q000737:chemistry*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D010539:Permeability; D010865:Pilot Projects; D018401:Sample Size; D012984:Software
chemical_list: D003287:Contrast Media
keywords: Tofts model; aneurysm; contrast leakage; rupture risk