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Table 4 Inter-observer variance

From: Non-contrast MR angiography at 1.5 Tesla for aortic monitoring in Marfan patients after aortic root surgery

  Inter-observer variance
  Mid-Graft Distal anastomosis Ascending aorta Aortic arch Descending aorta Diaphragm Celiac trunk
  2D SSFP
Mean difference (mm) 2.08 0.08 1.17 0.10 1.97 1.10 0.79
Limits of agreement (mm) −4.45 to 8.61 −4.43 to 4.59 −4.87 to 7.20 −5.04 to 5.24 −4.10 to 8.03 −6.34 to 8.55 −8.64 to 10.21
Standard deviation (mm) 3.33 2.30 3.1 2.62 3.10 3.80 4.81
Variance (mm2) 11.1 5.29 9.47 6.87 9.59 14.43 23.13
ICC 0.69 0.83 0.86 0.90 0.95 0.89 0.85
  3D CE-CMRA
Mean difference (mm) 2.34 1.38 1.44 0.41 2.69 1.62 0.95
Limits of agreement (mm) −4.8 to 9.56 −5.72 to 8.47 −3.54 to 6.43 −5.68 to 6.49 −9.31 to 14.70 −5.39 to 8.62 −4.34 to 6.25
Standard deviation (mm) 3.68 3.62 2.54 3.10 6.13 3.57 2.70
Variance (mm2) 13.57 13.11 6.47 9.63 37.53 12.77 7.29
ICC 0.48 0.68 0.84 0.78 0.75 0.87 0.88
p-value (t test) 0.543 0.023 0.385 0.549 0.350 0.064 0.069
p-value (F test) 0.443 0.001 0.440 0.220 <0.001 0.641 <0.001
  1. Inter-observer variance of measured aortic diameters as determined by non-contrast 2D bSSFP imaging and 3D CE-CMRA as described by Bland and Altman. Intraclass correlation coefficients (ICC) are given for both sequence types. Paired t-test was performed for comparison of mean differences and F test for comparison of variances. Significant differences are in bold (significant at p < .05)