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Table 3 Intra-observer variance

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

  Intra-observer variance
  Mid-Graft Distal anastomosis Ascending aorta Aortic arch Descending aorta Diaphragm Celiac trunk
  2D SSFP
Mean difference (mm) 0.22 0.38 0.56 0.14 −0.05 0.29 −0.07
Limits of agreement (mm) −3.18 to 3.62 −4.39 to 5.14 −3.59 to 4.70 −5.22 to 5.49 −4.21 to 4.10 −6.55 to 7.13 −7.64 to 7.51
Standard deviation (mm) 1.74 2.43 2.11 2.73 2.12 3.49 3.87
Variance (mm2) 3.01 5.92 4.47 7.47 4.50 12.17 14.95
ICC 0.95 0.88 0.94 0.89 0.98 0.96 0.94
  3D CE-CMRA
Mean difference (mm) 0.03 −0.23 0.17 0.58 0.19 0.33 0.73
Limits of agreement (mm) −3.60 to 3.66 −5.54 to 5.07 −2.55 to 2.88 −3.82 to 4.97 −4.32 to 4.72 −5.31 to 5.98 −6.69 to 8.16
Standard deviation (mm) 1.85 2.71 1.38 2.24 2.31 2.88 3.79
Variance (mm2) 3.44 7.34 1.92 5.02 5.31 8.29 14.35
ICC 0.92 0.84 0.97 0.93 0.95 0.96 0.92
p-value (t test) 0.491 0.140 0.480 0.367 0.589 0.922 0.869
p-value (F test) 0.605 0.398 0.089 0.133 0.530 0.144 0.870
  1. Intra-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