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Minimum detectable difference of MR diffusion maps in acute ischemic stroke
Author(s) -
Harris Ashley D.,
Govindaraj Mirthula,
Frayne Richard
Publication year - 2008
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21166
Subject(s) - diffusion mri , fractional anisotropy , region of interest , medicine , effective diffusion coefficient , nuclear medicine , stroke (engine) , white matter , acute stroke , magnetic resonance imaging , radiology , physics , tissue plasminogen activator , thermodynamics
Purpose To determine the minimum detectable difference (MDD) and investigate variability of region‐of‐interest (ROI) analysis of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in acute ischemic stroke. Materials and Methods Ten patients with acute stroke (<24 hours) and moderate‐to‐large infarcts were imaged using a fast diffusion tensor technique. Four observers repeated three trials, during which each of two ROI types (free‐hand polygon and ellipse) were drawn in white and gray matter (WM and GM) on FA and ADC maps. Analysis‐of‐variance techniques examined tissue and ROI type effects as well as inter‐ and intraobserver variability. F‐tests examined the variability differences between ROI types. Results The MDD for ADC was 0.160 × 10 −3 mm 2 s −1 in WM and 0.212 × 10 −3 mm 2 s −1 in GM. The FA MDD was 0.19 in WM and 0.10 in GM. Tissue but not ROI type affected the mean values for both ADC and FA maps. Intraobserver reliability was substantial, while interobserver reliability was poor‐to‐moderate. No variability differences were found by ROI types. Conclusion The MDD for WM and GM in normal and ischemic tissue were calculated. Inter‐ and intraobserver variability and tissue type affect ROI analysis of ADC and FA maps. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.