Validation of assessment methods for the apparent diffusion coefficient in a clinical trial of axial spondyloarthritis patients treated with golimumab

Jakob M Møller; Mikkel Østergaard; Henrik S Thomsen; Simon Krabbe; Inge J Sørensen; Bente Jensen; Ole Rintek Madsen; Mette Klarlund; Susanne J Pedersen

doi:10.1016/j.ejro.2020.100285

Validation of assessment methods for the apparent diffusion coefficient in a clinical trial of axial spondyloarthritis patients treated with golimumab

Eur J Radiol Open. 2020 Nov 5:7:100285. doi: 10.1016/j.ejro.2020.100285. eCollection 2020.

Authors

Jakob M Møller^{1

2}, Mikkel Østergaard^{2

3}, Henrik S Thomsen^{1

2}, Simon Krabbe^{2

3}, Inge J Sørensen^{2

3}, Bente Jensen⁴, Ole Rintek Madsen^{2

5}, Mette Klarlund³, Susanne J Pedersen^{2

3

5}

Affiliations

¹ Department of Radiology, Herlev and Gentofte Hospital, Herlev, Denmark.
² Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
³ Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup, Denmark.
⁴ Center for Rheumatology and Spine Diseases, Frederiksberg Hospital, Frederiksberg, Denmark.
⁵ Center for Rheumatology and Spine Diseases, Herlev and Gentofte Hospital, Hellerup, Denmark.

Abstract

Purpose: To compare three region-of-interest (ROI) settings in the assessment of ADC in a clinical trial, and to evaluate the effectiveness of ADC in assessing therapy-induced changes and predicting clinical outcomes.

Methods: In a 52-week clinical trial involving patients with axial spondyloarthritis, mean sacroiliac joint (SIJ) ADC measurements using structured, lesion-based, and index-lesion ROI-settings were assessed at baseline and weeks 4, 16, and 52. Variation among the three ROI-settings, correlations with Spondyloarthritis Research Consortium of Canada (SPARCC)-bone marrow edema (BME) SIJ inflammation indices, standardized response means (SRMs), and effectiveness in predicting clinical outcomes were analyzed.

Results: Forty of the 53 patients had at least one assessable SIJ lesion on ADC at baseline. The mean of the structured ROI ADC (ADC_struc) was 230 μmm²/s (standard deviation [SD] = 120). This was significantly lower (p < 0.01) than the means of the lesion-based ROI ADC (ADC_lesion = 420 μmm²/s, SD = 210) and index-lesion ROI ADC (ADC_index = 471 μmm²/s, SD = 278), which did not differ. ADC correlated with SPARCC-BME scores at baseline (p < 0.01) as did changes over time in ADC- and SPARCC-BME (p<0.05). At all follow-up time points, responsiveness was high for ADC_lesion (SRM > 0.92) and ADC_index (SRM > 0.87) while moderate for ADC_struc (SRM:0.54-0.67). Baseline ADC and changes in ADC did not predict clinical outcomes.

Conclusions: Lesion-based and index-lesion ROI ADC could both be used to evaluate the effectiveness of tumor necrosis factor inhibitor therapy. None of the methods could predict clinical outcomes.

Keywords: Apparent diffusion coefficient; Diffusion weighted; Magnetic resonance imaging; Region-of-interest; Spondyloarthritis.