Table 2

Agreement between ultrasound, MRI, conventional radiography and clinical examination for structural and soft tissue changes

PEAκ (95% CI)
US1 vs US2 (%)MRI1 vs MRI2 (%)US1 vs MRI1 (%)US1 vs US2MRI1 vs MRI2US1 vs MRI1
Bone erosions
 All9690780.90 (0.83 to 0.97)0.76 (0.64 to 0.88)0.55 (0.40 to 0.70)
 PIP joint (total)9688790.88 (0.76 to 1.0)0.68 (0.62 to 0.74)0.43 (0.17 to 0.70)
  EOA9387780.84 (0.69 to 0.99)0.65 (0.55 to 0.75)0.50 (0.20 to 0.80)
  Non-EOA10091801.00.70 (0.62 to 0.78)*
 DIP joint (total)9691770.90 (0.81 to 1.0)0.78 (0.72 to 0.85)0.53 (0.32 to 0.74)
  EOA9291750.83 (0.68 to 0.99)0.70 (0.55 to 0.86)0.36 (0.08 to 0.64)
  Non-EOA10093801.00.80 (0.70 to 0.90)0.52 (0.12 to 0.93)
Osteophytes/bony nodules
 All9261760.83 (0.75 to 0.91)0.15 (0.04 to 0.27)0.51 (0.35 to 0.66)
 PIP joint (total)9446730.87 (0.77 to 0.96)0.14 (0.03 to 0.24)0.48 (0.27 to 0.69)
  EOA9044670.77 (0.59 to 0.94)0.15 (0.02 to 0.28)0.35 (0.10 to 0.60)
  Non-EOA9850850.96 (0.88 to 1.0)*0.70 (0.39 to 1.01)
 DIP joint (total)9175790.78 (0.63 to 0.92)0.07 (0.03 to 0.11)0.43 (0.16 to 0.70)
  EOA9086810.70 (0.45 to 0.94)−0.05 (−0.12 to 0.03)0.26 (−0.13 to 0.65)
  Non-EOA9355750.84 (0.66 to 1.0)0.10 (0.00 to 0.20)0.50 (0.14 to 0.86)
Synovitis
 All9885870.93 (0.86 to 1.0)0.58 (0.40 to 0.76)0.55 (0.35 to 0.76)
 PIP joint (total)9683920.90 (0.80 to 1.0)0.42 (0.11 to 0.73)0.75 (0.52 to 0.98)
  EOA9581890.89 (0.76 to 1.0)0.41 (0.05 to 0.77)0.68 (0.39 to 0.97)
  Non-EOA98881000.90 (0.70 to 1.1)0.43 (0.23 to 0.63)1.0
 DIP joint (total)10087811.00.68 (0.47 to 0.89)0.36 (0.06 to 0.65)
  EOA10089751.00.77 (0.55 to 0.98)0.36 (0.08 to 0.64)
  Non-EOA10081941.0**
Effusion
 All9275730.84 (0.76 to 0.92)0.50 (0.35 to 0.65)0.41 (0.23 to 0.59)
 PIP joint (total)9173750.80 (0.67 to 0.92)0.41 (0.18 to 0.65)0.33 (0.31 to 0.36)
  EOA8769720.68 (0.48 to 0.88)0.43 (0.20 to 0.66)0.26 (0.08 to 0.61)
  Non-EOA9680800.91 (0.80 to 1.0)0.23 (0.08 to 0.38)0.47 (0.04 to 0.90)
 DIP joint (total)9477710.89 (0.79 to 0.98)0.54 (0.33 to 0.75)0.42 (0.19 to 0.66)
  EOA9075690.79 (0.62 to 0.96)0.42 (0.13 to 0.71)0.40 (0.11 to 0.68)
  Non-EOA10080751.00.38 (0.12 to 0.64)0.39 (0.03 to 0.75)
  • Values are presented as percentages of exact agreement (PEA) and unweighted κvalues (κ(95% CI)). The imaging modalities were ultrasonography, MRI and conventional radiography. To study interobserver reliability, agreement was studied for ultrasound between ultrasonographer 1 (RW, US1) and ultrasonographer 2 (PC, US2), and for MRI between MRI radiologist 1 (LJ, MRI1) and MRI radiologist 2 (VL, MRI2).

  • * Not possible to calculate κvalue because of empty cell in 2×2 table.

  • DIP, distal interphalangeal; EOA, erosive osteoarthritis; PIP, proximal interphalangeal.