Repeatability of quantitative metrics derived from MR diffusion tractography in paediatric patients with epilepsy.

Journal Article (Journal Article)

OBJECTIVE: To quantify the test-retest repeatability of mean diffusivity (MD) and fractional anisotropy (FA) derived from diffusion tensor imaging (DTI) tractography in a cohort of paediatric patients with localization-related epilepsy. METHODS: 30 patients underwent 2 DTI acquisitions [repetition time/echo time (ms), 7000/90; flip, 90°; b-value, 1000 s mm(-2); voxel (mm), 2 × 2 × 2]. Two observers used Diffusion Toolkit and TrackVis ( ) to segment and analyse the following tracts: corpus callosum, corticospinal tracts, arcuate fasciculi, inferior longitudinal fasciculi and inferior fronto-occipital fasciculi. Mean MD and mean FA were calculated for each tract. Each observer independently analysed one of the DTI data sets for every patient. RESULTS: Segmentation identified all tracts in all subjects, except the arcuate fasciculus. There was a highly consistent relationship between repeated observations of MD (r = 0.993; p < 0.0001) and FA (r = 0.990; p < 0.0001). For each tract, coefficients of variation ranged from 0.9% to 2.1% for MD and from 1.5% to 2.8% for FA. The 95% confidence limits (CLs) for change ranged from 2.8% to 6% for MD and from 4.3% to 8.6% for FA. For the arcuate fasciculus, Cohen's κ for agreement between the observers (identifiable vs not identifiable) was 1.0. CONCLUSION: We quantified the repeatability of two commonly utilized scalar metrics derived from DTI tractography. For an individual patient, changes greater than the repeatability coefficient or 95% CLs for change are unlikely to be related to variability in their measurement. ADVANCES IN KNOWLEDGE: Reproducibility of these metrics will aid in the design of future studies and might one day be used to guide management in patients with epilepsy.

Full Text

Duke Authors

Cited Authors

  • Paldino, MJ; Hedges, K; Rodrigues, KM; Barboriak, DP

Published Date

  • May 2014

Published In

Volume / Issue

  • 87 / 1037

Start / End Page

  • 20140095 -

PubMed ID

  • 24720623

Pubmed Central ID

  • PMC4075541

Electronic International Standard Serial Number (EISSN)

  • 1748-880X

Digital Object Identifier (DOI)

  • 10.1259/bjr.20140095


  • eng

Conference Location

  • England