Article Figures & Data
- Figure 1.
The discriminatory capacity of DWI in active cases and back pain controls was similar to the manual SPARCC scoring system. Active cases comprise Group 1 pretreatment and Group 2, and the controls by Group 3. ROC curve analysis for ADC DWI (AUC of 91%; p = 1.5 × 10−8) and SPARCC scores (AUC of 90%; p = 1.9 × 10−7). DWI: diffusion-weighted imaging; SPARCC: Spondyloarthritis Research Consortium of Canada; ROC: receiver-operator characteristic; ADC: apparent diffusion coefficient; AUC: area under the curve.
Group 1 Group 2 Group 3 Pretreatment Posttreatment No. 18 20 20 Age, yrs, mean (range) 38 (23–68) 40.6 (23–62) 37 (20–60) Sex (% male) 56 55 37 BASDAI 5.5 2 4.7 6.5 CRP 24.2 4.9 8.9 5.5 ESR 41.8 12 15.3 15.1 % HLA-B27 carriage 100 80 70 BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate.
- Table 2.
DWI ADC scores for different groups regarding each measurement in duplicate. Active group includes Group 1 pretreatment and Group 2. Duplicate measurements per side were averaged prior to the tests. Corrected values indicate sacroiliac sides subtracted from sacral and averaged.
Group 1 Pretreatment Group 1 Postreatment Group 2 Active Group 3 Mean SD Mean SD Mean SD Mean SD Mean SD ADC.right.1 0.672 0.425 0.408 0.144 0.947 0.409 0.820 0.434 0.403 0.146 ADC.right.2 0.665 0.414 0.448 0.124 0.949 0.423 0.818 0.438 0.400 0.150 ADC.left.1 0.831 0.543 0.598 0.356 0.802 0.492 0.815 0.509 0.415 0.150 ADC.left.2 0.846 0.517 0.609 0.339 0.835 0.502 0.840 0.502 0.416 0.160 ADC.sacrum.1 0.301 0.148 0.357 0.143 0.330 0.183 0.317 0.166 0.438 0.137 ADC.sacrum.2 0.306 0.163 0.367 0.140 0.332 0.178 0.820 0.434 0.439 0.136 Corrected score 0.450 0.433 0.154 0.23 0.552 0.273 0.505 0.354 −0.03 0.07 DWI: diffusion-weighted imaging; ADC: apparent diffusion coefficient.
- Table 3.
Comparisons of sacral and sacroiliac ADC values comparing different groups at matched sites. P values from paired t tests (Group 1 pre- vs posttreatment) or t tests (any other comparison) are displayed. Duplicate measurements per side were averaged prior to the tests. Corrected values indicate sacroiliac sides subtracted from sacral and averaged. For example, on the left side, Group 1 pretreatment scores were significantly different compared with Group 1 posttreatment scores (p = 0.0028), whereas comparing with Group 2 scores at this site was marginally significant (p = 0.05).
Group 1 Posttreatment Group 2 Group 3 Left Right Sacral Corrected Left Right Sacral Corrected Left Right Sacral Corrected Group 1 pretreatment 0.0028 0.0074 0.079 0.0017 0.89 0.23 0.48 0.39 0.0011 0.0084 0.0089 0.00021 Group 1 posttreatment — — — — 0.050 0.0012 0.85 1.7 × 10−5 0.025 0.26 0.080 0.0040 Group 2 — — — — 0.00015 9.0 × 10−5 0.085 2.0 × 10−9 ADC: apparent diffusion coefficient.
- Table 4.
Responsiveness analysis of ADC scores in comparison of active group with Group 3. For SPARCC scores, because the SD for Group 3 is zero, no effect size can be calculated.
Active Mean Active SD Group 3 Mean Group 3 SD Effect Size p ADC 0.50 0.35 −0.03 0.07 7.610 10−10 SPARCC 10.60 12.06 0.00 0.00 NA 9.6 × 10−6 ASDAS-CRP 3.42 1.28 2.77 0.89 0.736 0.049 ASDAS-ESR 3.37 1.25 2.88 0.94 0.529 0.14 ESR 27.84 23.08 15.10 13.98 0.911 0.026 CRP 16.13 19.00 5.51 6.57 1.618 0.0092 BASDAI 6.25 2.52 6.54 2.14 −0.135 0.78 BASFI 4.08 2.20 4.13 2.92 −0.019 0.94 BASMI 2.33 1.81 2.11 1.96 0.112 0.78 ADC: apparent diffusion coefficient; SPARCC: Spondyloarthritis Research Consortium of Canada; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; ASDAS: Ankylosing Spondylitis Disease Activity Score; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; BASFI: Bath Ankylosing Spondylitis Functional Index; BASMI: Bath Ankylosing Spondylitis Metrology Index.
- Table 5.
Responsiveness measures of magnetic resonance imaging scores and other measures in comparison of Group 1 cases pre- and posttreatment.
Group 1 Pretreatment Group 1 Posttreatment Effect Size SRM p Mean SD Mean SD ADC 0.45 0.43 0.15 0.23 −0.684 −0.877 0.0017 SPARCC 13.40 15.02 3.25 5.66 −0.676 −0.911 0.00083 ASDAS-CRP 4.32 0.62 1.75 0.99 −4.118 −2.273 7.9 × 10−8 ASDAS-ESR 4.29 0.69 1.72 0.99 −3.701 −2.372 6.3 × 10−8 ESR 41.78 24.03 12.00 12.22 −1.239 −1.335 6.3 × 10−5 CRP 24.18 18.07 4.88 4.57 −1.068 −1.050 0.00063 BASDAI 7.94 1.13 2.01 1.72 −5.237 −3.396 5 × 10−10 BASFI 5.02 1.45 2.70 2.02 −1.599 −1.029 0.00063 BASMI 2.78 2.14 1.82 2.00 −0.446 −0.953 0.00095 SRM: standardized response mean; ADC: apparent diffusion coefficient; SPARCC: Spondyloarthritis Research Consortium of Canada; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; ASDAS: Ankylosing Spondylitis Disease Activity Score; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; BASFI: Bath Ankylosing Spondylitis Functional Index; BASMI: Bath Ankylosing Spondylitis Metrology Index.
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