Inter- and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord

Table 1 Mean SD inter-rater and intra-rater values for fractional anisotropy, axial diffusivity (× 10^-3 mm²/s), radial diffusivity (×10^-3 mm²/s), and mean diffusivity (× 10^-3 mm²/s), for manually drawn regions of interest and fixed size regions of interest

			Pixels	FA	AD	RD	MD
Freehand ROI	Rater 1	Trial 1	24	0.50 ± 0.13	1.35 ± 0.52	0.70 ± 0.54	0.92 ± 0.53
		Trial 2	24	0.47 ± 0.13	1.16 ± 0.18	0.52 ± 0.17	0.73 ± 0.18
	Rater 2	Trial 1	17	0.48 ± 0.12	1.53 ± 0.65	0.88 ± 0.64	1.10 ± 0.65
		Trial 2	14	0.52 ± 0.10	1.20 ± 0.16	0.48 ± 0.13	0.72 ± 0.14
Fixed ROI	Rater 1	Trial 1	6	0.54 ± 0.10	1.18 ± 0.19	0.46 ± 0.14	0.70 ± 0.16
		Trial 2	6	0.54 ± 0.10	1.18 ± 0.16	0.47 ± 0.13	0.71 ± 0.14
	Rater 2	Trial 1	6	0.53 ± 0.10	1.64 ± 0.58	0.91 ± 0.56	1.16 ± 0.56
		Trial 2	6	0.54 ± 0.10	1.19 ± 0.15	0.45 ± 0.11	0.70 ± 0.12

ROI: Region of interest; FA: Fractional anisotropy; AD: Axial diffusivity; RD: Radial diffusivity; MD: Mean diffusivity.