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Table 1 Bland-Altman and correlation analysis of ultrasound and MRI results

From: Reproducibility and accuracy of optic nerve sheath diameter assessment using ultrasound compared to magnetic resonance imaging

  Descriptive statistics Reproducibility Inter-observer Intra-observer
(scan 1 vs. scan 2) variability variability
Bland-Altman Correlation Bland-Altman Correlation Bland-Altman Correlation
  Mean ± SD (range) d σd r P value d σd r P value d σd r P value
Ultrasound             
ONSD 3 mm 5.43 ± 0.49 −0.07 ±0.69 0.75 0.001 0.25 ±0.51 0.82 <0.001 −0.01 ±0.22 0.97 <0.001
(4.6 – 6.4)
ONSD 5 mm 5.53 ± 0.57 −0.11 ±0.66 0.82 <0.001 0.52 ±1.12 0.62 0.01 −0.09 ±0.47 0.90 <0.001
(4.8 – 6.8)
MR imaging             
ONSD 3 mm 5.69 ± 0.77 0.00 ±0.85 0.83 <0.001 −0.27 ±0.36 0.98 <0.001 −0.01 ±0.26 0.99 <0.001
(4.7 – 7.9)
ONSD 5 mm 5.09 ± 0.66 −0.01 ±0.87 0.76 0.001 −0.14 ±0.39 0.97 <0.001 0.01 ±0.25 0.98 <0.001
(4.2 – 7.1)
  1. d, mean difference; σd, limits of agreement; r, correlation coefficient.