Purpose: To compare manual region of interest (ROI) labeling and tract-based spatial statistics (TBSS) by their ability to detect group-wise differences in fractional anisotropy (FA) in the neonatal brain.
Materials and methods: Diffusion-weighted data were obtained for nine infants with hypoxic-ischemic encephalopathy (HIE) (six males, three females; gestational age [GA] range, 36-40 weeks; mean GA, 37.8 weeks) and 11 healthy-control infants (10 males, 1 female; GA range, 36-40 weeks; mean GA, 38.4 weeks) at 3T. For manual ROI labeling, ROIs were drawn freehand for each subject in eight, clinically relevant brain regions. For TBSS, all FA data underwent an optimized, automated protocol for neonates. Each method was evaluated for detection of decreased FA in HIE infants, sensitivity, specificity, and variability.
Results: FA values from manual ROI and TBSS were strongly correlated (r = 0.94, P < 0.0001). Both methods found decreased FA in most ROIs for HIE infants. There was no significant interaction between method and group, indicating a similar ability to detect FA differences (F(1,19) = 0.599, P = 0.449). Sensitivity (manual: 0.709, TBSS: 0.694, 95% CI [-0.136, 0.163], P = 0.856), specificity (manual and TBSS: 0.716, 95% CI [-0.133, 0.133], P = 1), and standard error (manual: 0.009, TBSS: 0.007) were comparable.
Conclusion: Manual ROI labeling and TBSS are comparable methods of diffusion analysis to detect group differences in FA in the neonatal brain.
Keywords: diffusion tensor imaging; fractional anisotropy; hypoxic-ischemic encephalopathy; neonates; tract-based spatial statistics.
© 2015 Wiley Periodicals, Inc.