| |
Lesion
|
Per subject
|
Ilium R+L
|
Sacrum R+L
|
P-value Ilium versus Sacrum
|
|---|
|
AS patients (number = 30)
| | | | | |
|
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
|
- 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.
