Table 2 |
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|
Frequency of MRI lesions recorded by four readers jointly and percentage concordance among six possible reader pairs. |
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|
Lesion |
Per subject |
Ilium R+L |
Sacrum R+L |
P-value Ilium versus Sacrum |
|
|
|
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|
AS patients (number = 30) |
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|
Frequency: median (IQR)a |
ER |
11.4 (9.0) |
8.6 (6.9) |
2.1 (2.9) |
< 0.0001 |
|
BME |
13.1 (15.1) |
6.8 (10.4) |
5.1 (7.9) |
0.67 |
|
|
FI |
10.9 (11.7) |
4.5 (5.3) |
5.6 (7.0) |
0.06 |
|
|
EE |
1.1 (1.4) |
1.0 (1.0) |
0.0 (0.3) |
< 0.0001 |
|
|
BF |
1.0 (1.3) |
0.8 (1.3) |
0.0 (0.3) |
< 0.0001 |
|
|
% Concordance six RP: total (positive/negative)b |
ER |
73.9 (56.9/16.9) |
80.0 (75.0/5.0) |
67.8 (38.9/28.9) |
N/A |
|
BME |
85.0 (60.4/24.6) |
79.7 (60.3/19.4) |
90.3 (60.6/29.7) |
N/A |
|
|
FI |
69.7 (43.6/26.1) |
66.4 (35.3/31.1) |
73.1 (51.9/21.1) |
N/A |
|
|
EE |
75.7 (19.7/56.0) |
65.8 (32.5/33.3) |
85.6 (6.9/78.6) |
N/A |
|
|
BF |
80.0 (13.8/66.3) |
70.3 (24.7/45.6) |
89.7 (2.8/86.9) |
N/A |
|
|
Controls (number = 30) |
|||||
|
Frequency: median (IQR)a |
ER |
0 (0.4) |
0 (0.3) |
0 (0.0) |
0.02 |
|
BME |
0.1 (0.9) |
0 (0.4) |
0 (0.3) |
0.81 |
|
|
FI |
0 (2.1) |
0 (0.9) |
0 (0.2) |
0.26 |
|
|
EE |
0 (0.0) |
0 (0.0) |
0 (0.0) |
N/A |
|
|
BF |
0 (0.0) |
0 (0.0) |
0 (0.0) |
0.98 |
|
|
% Concordance six RP: total (positive/negative)b |
ER |
92.1 (0.8/91.3) |
87.8 (1.4/86.4) |
96.4 (0.3/96.1) |
N/A |
|
BME |
89.3 (1.9/87.4) |
88.6 (2.2/86.4) |
90.0 (1.7/88.3) |
N/A |
|
|
FI |
83.8 (2.9/80.8) |
80.3 (4.7/75.6) |
87.2 (1.1/86.1) |
N/A |
|
|
EE |
100.0 (0.0/100.0) |
100.0 (0.0/100.0) |
100.0 (0.0/100.0) |
N/A |
|
|
BF |
98.7 (0.2/98.5) |
98.1 (0.3/97.8) |
99.2 (0.0/99.2) |
N/A |
|
|
|
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|
aFrequency of lesions: for ER, BME and FI the number of SIJ quadrants affected; for EE and BF the number of joint surfaces affected irrespective of the number of SIJ MRI slices; bpercentage concordance among six possible reader pairs for 60 joint surfaces (Ilium R+L; Sacrum R+L) and for 120 joint surfaces (per subject). AS, ankylosing spondylitis; BF, backfill; BME, bone marrow edema; EE, extended erosion; ER, erosion; FI, fat infiltration; IQR, interquartile range; L, left; N/A, not applicable; R, right; RP, reader pair; % Concordance six RP, percentage concordance among six possible reader pairs (100% = six concordant reader pairs); total = positive and negative concordance. |
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|
Weber et al. Arthritis Research & Therapy 2012 14:R124 doi:10.1186/ar3854 |
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