title: Spatially constrained incoherent motion method improves diffusion-weighted MRI signal decay analysis in the liver and spleen.
abstract: OBJECTIVE
  To evaluate the effect of the spatially constrained incoherent motion (SCIM) method on improving the precision and robustness of fast and slow diffusion parameter estimates from diffusion-weighted MRI in liver and spleen in comparison to the independent voxel-wise intravoxel incoherent motion (IVIM) model.
  
  
  METHODS
  We collected diffusion-weighted MRI (DW-MRI) data of 29 subjects (5 healthy subjects and 24 patients with Crohn's disease in the ileum). We evaluated parameters estimates' robustness against different combinations of b-values (i.e., 4 b-values and 7 b-values) by comparing the variance of the estimates obtained with the SCIM and the independent voxel-wise IVIM model. We also evaluated the improvement in the precision of parameter estimates by comparing the coefficient of variation (CV) of the SCIM parameter estimates to that of the IVIM.
  
  
  RESULTS
  The SCIM method was more robust compared to IVIM (up to 70% in liver and spleen) for different combinations of b-values. Also, the CV values of the parameter estimations using the SCIM method were significantly lower compared to repeated acquisition and signal averaging estimated using IVIM, especially for the fast diffusion parameter in liver (CVIV IM = 46.61 ± 11.22, CVSCIM = 16.85 ± 2.160, p < 0.001) and spleen (CVIV IM = 95.15 ± 19.82, CVSCIM = 52.55 ± 1.91, p < 0.001).
  
  
  CONCLUSIONS
  The SCIM method characterizes fast and slow diffusion more precisely compared to the independent voxel-wise IVIM model fitting in the liver and spleen.
authors.affiliation: Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Vahid
authors.initials: V
authors.lastname: Taimouri
authors.affiliation: Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Onur
authors.initials: O
authors.lastname: Afacan
authors.affiliation: Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Jeannette M
authors.initials: JM
authors.lastname: Perez-Rossello
authors.affiliation: Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Callahan
authors.affiliation: Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Robert V
authors.initials: RV
authors.lastname: Mulkern
authors.affiliation: Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Simon K
authors.initials: SK
authors.lastname: Warfield
authors.affiliation: Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: Moti
authors.initials: M
authors.lastname: Freiman
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000473:pathology; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007082:Ileum; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000033:anatomy & histology* / Q000473:pathology; D008297:Male; D008962:Models, Theoretical; D009038:Motion; D013154:Spleen / Q000033:anatomy & histology* / Q000473:pathology; D055815:Young Adult
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