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Table 3 Inter-observer regional mean FA (0-1, unitless), ADC (10−3 mm2/s), AD (10−3 mm2/s) and RD (10−3 mm2/s) values ± standard deviation (mean ± SD) values, variation (the percent coefficients of variation = CV%) and repeatability (mean difference ± 2SD) (observer 1 & 2) (N = 15)

From: Reliability of the freehand region-of-interest method in quantitative cerebral diffusion tensor imaging

Region   Obs. 1 Obs. 2 Obs. 1 Obs. 2 Obs.1 and Obs. 2
Mean ± SD Mean ± SD CV(%) CV(%) Mean diff ± 2SD
Cerebral peduncle FA 0.817 ± 0.039 0.818 ± 0.033 4.8 4.1 − 0.001 ± 0.057
ADC 0.731 ± 0.049 0.721 ± 0.051 6.7 7.1 0.010 ± 0.072
AD 1.652 ± 0.115 1.632 ± 0.113 7.0 6.9 0.021 ± 0.139
RD 0.271 ± 0.052 0.270 ± 0.048 19.2 17.7 0.000 ± 0.065
Internal capsule (posterior) FA 0.707 ± 0.027 0.719 ± 0.040 3.8 5.6 − 0.012 ± 0.053
ADC 0.709 ± 0.025 0.711 ± 0.028 3.5 4.0  − 0.002 ± 0.031
AD 1.403 ± 0.043 1.435 ± 0.064 3.1 4.5  − 0.033 ± 0.101
RD 0.360 ± 0.030 0.346 ± 0.040 8.3 11.5 0.014 ± 0.044
Corona radiata FA 0.524 ± 0.049 0.522 ± 0.050 9.3 9.6 0.002 ± 0.049
ADC 0.683 ± 0.038 0.686 ± 0.043 5.5 6.3  − 0.003 ± 0.028
AD 1.099 ± 0.049 1.108 ± 0.055 4.4 5.0  − 0.008 ± 0.069
RD 0.475 ± 0.052 0.477 ± 0.056 10.9 11.7  − 0.002 ± 0.036
Centrum semiovale FA 0.571 ± 0.080 0.579 ± 0.054 14.1 9.3  − 0.008 ± 0.133
ADC 0.716 ± 0.029 0.708 ± 0.035 4.1 4.9 0.009 ± 0.033
AD 1.238 ± 0.082 1.299 ± 0.046 6.6 3.7 0.010 ± 0.182
RD 0.456 ± 0.064 0.447 ± 0.051 14.1 11.3 0.009 ± 0.080
Uncinate fasciculus FA 0.595 ± 0.057 0.562 ± 0.054 9.6 9.6 0.033 ± 0.033
ADC 0.789 ± 0.050 0.786 ± 0.041 6.3 5.2 0.003 ± 0.043
AD 1.403 ± 0.069 1.348 ± 0.065 4.9 4.9 0.054 ± 0.089
RD 0.482 ± 0.065 0.505 ± 0.057 13.5 11.3  − 0.023 ± 0.035
Forceps minor FA 0.529 ± 0.072 0.494 ± 0.069 13.5 14 0.034 ± 0.113
ADC 0.768 ± 0.037 0.771 ± 0.044 4.8 5.7  − 0.002 ± 0.051
AD 1.275 ± 0.073 1.234 ± 0.063 5.7 5.1 0.041 ± 0.126
RD 0.515 ± 0.064 0.539 ± 0.066 12.5 12.3  − 0.024 ± 0.093
Thalamus FA 0.322 ± 0.031 0.315 ± 0.027 9.5 8.5 0.006 ± 0.050
ADC 0.755 ± 0.028 0.750 ± 0.028 3.7 3.8 0.005 ± 0.018
AD 1.005 ± 0.031 0.992 ± 0.024 3.1 2.5 0.012 ± 0.054
RD 0.630 ± 0.034 0.629 ± 0.033 5.4 5.3 0.001 ± 0.028
CC Genu FA 0.868 ± 0.042 0.849 ± 0.057 4.8 6.7 0.019 ± 0.064
ADC 0.745 ± 0.047 0.760 ± 0.055 6.3 7.2  − 0.015 ± 0.085
AD 1.808 ± 0.093 1.799 ± 0.109 5.2 6.0 0.009 ± 0.186
RD 0.213 ± 0.062 0.240 ± 0.081 29.1 33.7  − 0.026 ± 0.086
CC Splenium FA 0.868 ± 0.050 0.862 ± 0.054 5.7 6.2 0.006 ± 0.092
ADC 0.733 ± 0.067 0.749 ± 0.053 9.2 6.2  − 0.017 ± 0.098
AD 1.778 ± 0.140 1.805 ± 0.112 7.9 6.2  − 0.027 ± 0.136
RD 0.210 ± 0.074 0.222 ± 0.076 35.2 34.4  − 0.011 ± 0.136
  1. FA, fractional anisotropy; ADC, apparent diffusion coefficient; AD, axial diffusivity; RD, radial diffusivity
  2. CV, coefficient of variation; CC, corpus callosum; diff, difference; SD, standard deviation