Background
Methods
Evaluation of BME of the SIJ and spine
Evaluation of structural lesions
Structural lesions seen on T1WSE MRI: standardized definitions
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Erosion: on T1WSE is the full-thickness loss of the dark appearance of iliac or sacral cortical bone at its anticipated location as well as loss of the normal bright appearance of adjacent bone marrow.
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Backfill: on T1WSE is the complete loss of iliac or sacral cortical bone at its anticipated location as well as increased signal clearly demarcated from adjacent normal marrow by dark signal with irregular contour reflecting sclerosis at the border of the eroded bone.
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Fat metaplasia: increased signal on T1WSE sequences. To be scored in the SPARCC SSS method, there must be homogeneous signal across the lesion, and it must extend >1 cm in depth from the joint surface.
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Ankylosis: bone marrow signal on T1WSE between the sacral and iliac bone marrow with a full-thickness loss of the dark appearance of the iliac and sacral cortical bone.
Statistical analysis
Results
Patients
SPARCC SIJ BME ≥2 (N = 128) | SPARCC SIJ BME <2 (N = 55) | Total (N = 183) | |||||||
---|---|---|---|---|---|---|---|---|---|
SSS >0 n = 69 | SSS = 0 n = 59 |
P value | SSS >0 n = 7 | SSS = 0 n = 48 |
P value | SSS >0 n = 76 | SSS = 0 n = 107 |
P value | |
Age, years* | 30.3 (6.8) | 33.5 (7.7) | 0.01 | 33.9 (11.9) | 32.6 (8.5) | 0.73 | 30.6 (7.3) | 33.1 (8.0) | 0.04 |
Male, n (%)†
| 57 (82.6) | 28 (47.5) | <0.001 | 3 (42.9) | 22 (45.8) | 1.0 | 60 (79.0) | 50 (46.7) | <0.001 |
BMI, kg/m2* | 24.5 (3.6) | 25.2 (4.6) | 0.34 | 25.3 (5.6) | 25.4 (5.2) | 0.96 | 24.6 (3.8) | 25.3 (4.9) | 0.29 |
Symptom duration, years* | 2.5 (2.2) | 2.7 (1.4) | 0.47 | 2.6 (1.5) | 1.9 (1.4) | 0.22 | 2.5 (2.2) | 2.4 (1.4) | 0.64 |
HLA-B27 positive, n (%)‡
| 60 (87.0) | 37 (62.7) | 0.002 | 6 (85.7) | 29 (60.4) | 0.40 | 66 (86.8) | 66 (61.7) | <0.001 |
Anterior uveitis, n (%)‡
| 7 (10.1) | 6 (10.2) | 1.0 | 0 | 1 (2.1) | 1.0 | 7 (9.2) | 7 (6.5) | 0.58 |
IBD, n (%)‡
| 0 | 0 | 1.0 | 0 | 1 (2.1) | 1.0 | 0 | 1 (0.9) | 1.0 |
PsO, n (%)‡
| 8 (11.6) | 10 (17.0) | 0.45 | 0 | 5 (10.4) | 1.0 | 8 (10.5) | 15 (14.0) | 0.51 |
PsO family history, n (%)‡
| 4 (5.8) | 1 (1.7) | 0.38 | 0 | 3 (6.3) | 1.0 | 4 (5.3) | 4 (3.7) | 0.72 |
ASDAS-CRP | 3.1 (1.1) | 3.1 (0.9) | 0.98 | 2.3 (1.2) | 2.8 (0.8) | 0.11 | 3.0 (1.1) | 3.0 (0.9) | 0.85 |
CRP, mg/l | 7.7 (9.6) | 7.6 (14.7) | 0.96 | 5.3 (9.3) | 5.0 (7.0) | 0.93 | 7.5 (9.6) | 6.4 (11.9) | 0.53 |
BASDAI, 0–10 | 5.7 (2.0) | 6.4 (1.6) | 0.03 | 4.5 (2.3) | 6.0 (1.6) | 0.03 | 5.6 (2.0) | 6.2 (1.6) | 0.02 |
BASFI, 0–10 cm VAS | 3.7 (2.5) | 4.6 (2.6) | 0.04 | 3.0 (1.4) | 3.9 (2.2) | 0.30 | 3.6 (2.5) | 4.3 (2.4) | 0.07 |
BASMI, 0–10 | 1.0 (1.2) | 1.4 (1.5) | 0.14 | 1.2 (0.9) | 1.4 (1.4) | 0.72 | 1.1 (1.2) | 1.4 (1.4) | 0.10 |
SPARCC spine score, 23-DVU, 0–414 | 6.9 (11.9) | 4.0 (5.8) | 0.10 | 2.5 (3.9) | 2.5 (3.9) | 0.99 | 6.5 (11.5) | 3.3 (5.1) | 0.01 |
SPARCC spine score, 23-DVU 0–414, median§
| 2.0 | 1.5 | 0.39 | 1.0 | 0.8 | 0.85 | 2.0 | 1.5 | 0.12 |
SPARCC SIJ BME | Erosion | Backfill | Fat metaplasia | Ankylosis | |||||
---|---|---|---|---|---|---|---|---|---|
≥2 n = 128 | >0 n = 58 | 0 n = 70 | >0 n = 26 | 0 n = 102 | >0 n = 14 | 0 n = 114 | >0 n = 3 | 0 n = 125 | |
<2 n = 55 | >0 n = 6 | 0 n = 49 | >0 n = 0 | 0 n = 55 | >0 n = 1 | 0 n = 54 | >0 n = 1 | 0 n = 54 | |
Age, years | ≥2 | 30.0 (6.1) | 33.2 (8.0) | 28.9 (6.9) | 32.5 (7.3) | 32.3 (7.6) | 31.7 (7.3) | 26.3 (1.2) | 31.9 (7.4) |
<2 | 35.3 (12.4) | 32.4 (8.4) | ─ | 32.7 (8.8) | 40.0 | 32.6 (8.9) | 25.0 | 32.9 (8.9) | |
Male, n (%) | ≥2 | 51 (87.9) | 34 (48.6) | 21 (80.8) | 64 (62.8) | 12 (85.7) | 73 (64.0) | 3 (100) | 82 (65.6) |
<2 | 3 (50.0) | 22 (44.9) | ─ | 25 (45.5) | 1 (100) | 24 (44.4) | 0 | 25 (46.3) | |
BMI, kg/m2
| ≥2 | 24.6 (3.5) | 25.1 (4.5) | 24.7 (3.8) | 24.9 (4.2) | 25.1 (3.1) | 24.8 (4.2) | 25.9 (4.9) | 24.8 (4.1) |
<2 | 26.7 (4.8) | 25.3 (5.3) | ─ | 25.4 (5.2) | 30.1 | 25.4 (5.3) | 17.3 | 25.6 (5.2) | |
Symptom duration, years | ≥2 | 2.5 (2.3) | 2.7 (1.5) | 3.0 (2.9) | 2.5 (1.5) | 3.2 (1.7) | 2.5 (1.9) | 4.0 (1.2) | 2.5 (1.9) |
<2 | 2.4 (1.5) | 2.0 (1.4) | ─ | 2.0 (1.4) | 0.3 | 2.0 (1.4) | 4.0 | 2.0 (1.4) | |
HLA-B27 positive, n (%) | ≥2 | 50 (86.2) | 47 (67.1) | 25 (96.2) | 72 (70.6) | 12 (85.7) | 85 (74.6) | 3 (100) | 94 (75.2) |
<2 | 5 (83.3) | 30 (61.2) | ─ | 35 (63.6) | 1 (100) | 34 (63.0) | 1 (100) | 34 (63.0) | |
Anterior uveitis, n (%) | ≥2 | 5 (8.6) | 8 (11.4) | 1 (3.9) | 12 (11.8) | 2 (14.3) | 11 (9.7) | 1 (33.3) | 12 (9.6) |
<2 | 0 | 1 (2.0) | ─ | 1 (1.8) | 0 | 1 (1.9) | 0 | 1 (1.9) | |
IBD, n (%) | ≥2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
<2 | 0 | 1 (2.0) | ─ | 1 (1.8) | 0 | 1 (1.9) | 0 | 1 (1.9) | |
PsO, n (%) | ≥2 | 6 (10.3) | 12 (17.1) | 2 (7.7) | 16 (15.7) | 3 (21.4) | 15 (13.2) | 0 | 18 (14.4) |
<2 | 0 | 5 (10.2) | ─ | 5 (9.1) | 0 | 3 (5.6) | 0 | 5 (9.3) | |
PsO family history, n (%) | ≥2 | 4 (6.9) | 1 (1.4) | 0 | 5 (4.9) | 1 (7.1) | 4 (3.5) | 0 | 5 (4.0) |
<2 | 0 | 3 (6.1) | ─ | 3 (5.5) | 0 | 3 (5.6) | 0 | 3 (5.6) | |
ASDAS-CRP | ≥2 | 3.0 (1.1) | 3.1 (0.9) | 3.2 (1.1) | 3.0 (1.0) | 2.7 (0.7) | 3.1 (1.0) | 3.1 (0.1) | 3.1 (1.0) |
<2 | 2.4 (1.3) | 2.8 (0.8) | ─ | 2.8 (0.9) | 0.7 | 2.8 (0.8) | 1.8 | 2.8 (0.9) | |
CRP, mg/l | ≥2 | 7.6 (9.7) | 7.7 (13.9) | 8.6 (9.5) | 7.4 (12.8) | 4.0 (4.1) | 8.1 (12.8) | 2.8 (2.2) | 7.7 (12.3) |
<2 | 5.8 (10.0) | 4.9 (7.0) | ─ | 5.0 (7.2) | 1.3 | 5.1 (7.3) | 2.2 | 5.1 (7.3) | |
BASDAI, 0–10 | ≥2 | 5.6 (2.0) | 6.4 (1.7) | 5.9 (2.3) | 6.1 (1.7) | 5.4 (1.9) | 6.1 (1.8) | 6.8 (1.2) | 6.0 (1.9) |
<2 | 4.7 (2.5) | 5.9 (1.6) | ─ | 5.8 (1.7) | 0.4 | 5.9 (1.6) | 3.5 | 5.8 (1.7) | |
BASFI, 0–10 cm VAS | ≥2 | 3.6 (2.6) | 4.5 (2.5) | 3.7 (2.8) | 4.2 (2.5) | 3.6 (2.0) | 4.2 (2.6) | 4.5 (0.7) | 4.1 (2.6) |
<2 | 3.0 (1.6) | 3.9 (2.2) | ─ | 3.8 (2.1) | 0.5 | 3.8 (2.1) | 2.9 | 3.8 (2.2) | |
BASMI, 0–10 | ≥2 | 1.1 (1.3) | 1.3 (1.4) | 1.1 (1.5) | 1.2 (1.3) | 0.9 (1.1) | 1.3 (1.4) | 1.3 (2.2) | 1.2 (1.3) |
<2 | 1.2 (1.0) | 1.4 (1.3) | ─ | 1.3 (1.3) | 0 | 1.4 (1.3) | 1.3 | 1.3 (1.3) | |
SPARCC spine score, 23-DVU, 0–414 | ≥2 | 7.5 (12.8) | 4.0 (5.7) | 9.1 (16.1) | 4.6 (7.1) | 5.6 (7.7) | 5.5 (9.9) | 11.7 (14.9) | 5.4 (9.6) |
<2 | 2.8 (4.2) | 2.5 (3.9) | ─ | 2.5 (3.9) | 3.5 | 2.5 (3.9) | 1.0 | 2.5 (3.9) |
MRI structural lesions and SIJ BME according to radiographic grade
Radiographic grade | MRI inflammation | MRI structural lesion | ||||
---|---|---|---|---|---|---|
SPARCC SIJ BME ≥ 2 | SSS > 0 | Erosion > 0 | Fat Metaplasia > 0 | Backfill > 0 | Ankylosis > 0 | |
Bilateral grade 0 | 23/37 (62.2) | 11/38 (28.9) | 10/38 (26.3) | 2/38 (5.3) | 3/38 (7.9) | 0/38 (0) |
Unilateral grade 1 | 25/40 (62.5) | 10/41 (24.4) | 10/41 (24.4) | 2/41 (4.9) | 2/41 (4.9) | 0/41 (0) |
Unilateral grade 2 | 6/6 (100) | 2/6 (33.3) | 1/6 (16.7) | 0/6 (0) | 2/6 (33.3) | 0/6 (0) |
Bilateral grade 1 | 28/41 (68.3) | 15/41 (36.6) | 9/41 (22.0) | 0/41 (0) | 5/41 (12.2) | 2/41 (4.9) |
Unilateral grade 1 and contralateral grade 2 | 46/59 (78.0) | 39/59 (66.1) | 35/59 (59.3) | 11/59 (18.6) | 14/59 (23.7) | 2/59 (3.4) |
P value* | 0.16 | <0.001 | <0.001 | 0.008 | 0.03 | 0.45 |