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Table 5 Correction of 2D measurements using linear regression equations

From: Effects of positioning on radiographic measurements of ankle morphology: a computerized tomography-based simulation study

   Perturbed pose (3 Deg) Perturbed pose (6 Deg)
   Error (%) Corrected error (%) Error (%) Corrected error (%)
Sagittal Plane Tibia Part     
  TiAL 2.17 -1.02 4.41 1.12
  TiSR 3.17 -0.05 4.87 1.59
  APG 3.51 -0.14 13.34 9.42
  APA 2.69 2.69 8.40 8.40
  MTiTh 2.91 -1.66 5.56 0.25
  MDA 31.36 8.42 65.25 35.96
  MDV 25.43 8.63 33.46 12.09
  Talus Part     
  TaAL -8.57 1.95 -5.92 0.58
  TaR 7.08 1.10 8.35 1.84
Frontal Plane Tibia part     
  TiW 4.97 -1.85 6.87 -0.23
  MalW 2.37 0.54 3.54 1.66
  MLATi 2.21 2.07 2.74 2.60
  Talus part     
  TaW -10.61 -8.78 -16.36 -14.07
  MLATa 29.80 14.76 50.54 29.11
  1. *Error = 100% × (2D - 3D)/3D.
  2. Mean residual errors of 2D measurements of the morphological parameters made on two sets of DRR images produced from 3D poses with random errors in the three individual rotational components for up to 3 degrees and 6 degrees, respectively, before and after corrections using the linear regression equations derived from data in the standard pose.