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Table 2 Intramodality and intermodality agreements of single and total erosion volume, measured on computed tomography (CT) and magnetic resonance imaging (MRI)

From: Detection of bone erosions in rheumatoid arthritis wrist joints with magnetic resonance imaging, computed tomography and radiography

 

Reading A (mm3)

Reading B (mm3)

Mean of readings A and B (mm3)

Spearman ρ

Absolute difference (mm3)a

Absolute numerical difference (mm3)

Relative difference (%)b

Relative numerical difference (%)

Coefficient of variation

Intramodality agreement: CT (reading A) vs CT (reading B) and MRI (reading A) vs MRI (reading B)

Volume per erosion

         

CT (n = 135)

13 (4; 1–245)

14 (4; 1–264)

13 (4; 1–255)

0.92*

-1 (0; -28 to 12)

2 (1; 0–28)

-7 (0; -120 to 100)

29 (22; 0–120)

0.15 (0.11; 0–0.60)

MRI (n = 90)

17 (10; 1–132)

17 (11; 1–138)

17 (11; 1–133)

0.90*

0 (0; -23 to 18)

4 (3; 0–23)

0 (0; -100 to 86)

28 (25; 0–100)

0.14 (0.13 0–0.50)

Volume per person with erosions

         

CT (n = 17)

102 (49; 2–519)

108 (56; 3–535)

105 (55; 3–527)

0.99*

-6 (-2; -54 to 19)

12 (7; 1–54)

-10 (-6; -43 to 15)

16 (15; 3–43)

0.08 (0.07; 0.02–0.21)

MRI (n = 15)

101 (80; 5–409)

100 (78; 5–409)

100 (76; 5–409)

0.95*

1 (0; -23 to 18)

7 (5; 0–23)

2 (0; -22 to 25)

8 (6; 0–25)

0.04 (0.03; 0–0.13)

Intermodality agreement (CT vs MRI) c

Volume per erosion of all concordant erosions (n = 64)

         

CT

21 (5; 1–245)

22 (5; 1–255)

21 (5; 1–255)

      
    

0.55*

2 (-5; -55 to 132)

17 (9; 0–131)

-54 (-59; -174 to 167)

90 (92; 0–174)

0.46 (0.45; 0–0.87)

MRI

20 (13; 1–132)

19 (13; 1–138)

19 (13; 1–133)

      

Total volume per person of all concordant erosions (n = 15)

         

CT

88 (18; 1–514)

93 (23; 1–528)

91 (21; 1–521)

      
    

0.89*

8 (-7; -56 to 147)

40 (16; 4–147)

-48 (-63; -139 to 64)

72 (64; 6–139)

0.36 (0.32; 0.03–0.70)

MRI

83 (78; 5–374)

83 (62; 5–375)

83 (71; 5–375)

      

Total volume per person of all erosions (n = 19)

         

CT

91 (36; 0–519)

100 (49, 0–535)

94 (38; 0–527)

      
    

0.82*

15 (2; -60 to 118)

41 (31; 0–118)

13 (6; -129 to 200)

68 (52; 0–200)

0.34 (0.26; 0–1.0)

MRI

79 (67; 0–409)

79 (67; 0–409)

79 (63; 0–409)

      
  1. Data presented as the mean (median; range). Reading A and reading B, volumes obtained at the first (reading A) and second (reading B) volume measurements, done by the same observer 1 week apart. The mean value of volumes obtained at reading A and B was used for the comparison of CT and MRI volumes. *P < 0.01. aIntramodality agreement, reading A minus reading B; intermodality agreement, CT erosion volume minus MRI erosion volume. bIntramodality agreement, positive values refer to larger erosion volume at reading A than reading B, and vice versa; intermodality agreement, positive values refer to larger erosion volume on CT than MRI, and vice versa. cValues on intermodality agreement are comparisons between CT and MRI erosions volumes.
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Arthritis Research & Therapy

ISSN: 1478-6362

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