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Objectives: To investigate whether antibody response patterns against Klebsiella pneumoniae capsular serotypes can discriminate patients with axial spondyloarthritis (axSpA) from patients with non-specific low back pain (LBP).Method: Immunoglobulin (Ig)G and IgA antibodies against K. pneumoniae capsular serotypes K2, K26, K36, and K50 were measured, and antibody seropositivity compared between groups and analysed for patient correlation in five different groups: (a) 96 patients fulfilling the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axSpA; (b) 38 patients with either a positive magnetic resonance imaging (MRI) scan as defined by ASAS or a positive human leucocyte antigen (HLA)-B27 status plus one clinical SpA feature, characterized as 'non-axSpA'; (c) 82 non-specific LBP patients; (d) 40 healthy blood donors and (e) 43 patients with diagnosed ankylosing spondylitis (AS) served as the negative and positive control groups.Results: There was no difference in IgG and IgA seropositivity against all serotypes between the axSpA, non-axSpA, and LBP groups. No significant correlations were found between anti-Klebsiella antibodies and age, gender, HLA-B27, or high-sensitivity C-reactive protein (hsCRP). IgG seropositivity against K50 was more frequent in AS (25.6%) than in axSpA (13.5%, p < 0.05). axSpA patients with radiographic sacroiliitis and AS controls concordantly had the highest frequency of seropositivity for ≥ 2 serotypes (21%).Conclusions: The antibody patterns against K. pneumoniae serotypes K2, K26, K36, and K50 did not discriminate between early axSpA and non-specific LBP. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the current study was to investigate the diagnostic value of three sacroiliac (SI) joint pain provocation tests for sacroiliitis identified by magnetic resonance imaging (MRI) and stratified by gender.Method: Patients without clinical signs of nerve root compression were selected from a cohort of patients with persistent low back pain referred to an outpatient spine clinic. Data from Gaenslen's test, the thigh thrust test, and the long dorsal sacroilia ligament test and sacroiliitis identified by MRI were analysed.Results: The median age of the 454 included patients was 33 (range 18-40) years and 241 (53%) were women. The prevalence of SI joints with sacroiliitis was 5%. In the whole study group, only the thigh trust test was associated with sacroiliitis, the area under the receiver operating characteristic (ROC) curve (AUC) was 0.58 [95% confidence interval (CI) 0.51-0.65], sensitivity 31% (95% CI 18-47), and specificity 85% (95% CI 82-87). In men, sacroiliitis was associated with all the SI joint tests assessed and multi-test regimens, with the greatest AUC found for at least one positive out of three tests [AUC 0.68 (95% CI 0.56-0.80), sensitivity 56% (95% CI 31-79), and specificity 81% (95% CI 77-85)]. In women, no significant associations were observed between the SI joint tests and sacroiliitis.Conclusions: Only in men were the SI joint tests found to be associated with sacroiliitis identified by MRI. Although, the diagnostic value was relatively low, the results indicate that the use of SI joint tests for sacroiliitis may be optimized by gender-separate analyses. [ABSTRACT FROM AUTHOR]

Objective: To investigate the prognostic value of the two arms of the Assessment of SpondyloArthritis international Society (ASAS) criteria regarding the progression of structural lesions in the sacroiliac joints (SIJs)., Methods: Information on baseline fulfilment of the ASAS criteria and baseline and follow-up magnetic resonance imaging of the SIJ in 603 patients aged 18-40 years referred with low back pain to an outpatient spine were collected. Magnetic resonance imaging positivity was defined as bone marrow oedema (BMO) in two or more consecutive slices or two or more lesions in one slice, as described in the ASAS definition of sacroiliitis., Results: Of 71 participants fulfilling the ASAS criteria at baseline, 66 (93%) fulfilled the 'imaging arm' and 14 (20%) fulfilled the 'clinical arm'. The 'clinical arm' predicted the progression of erosions with an odds ratio of 55 (compared with not fulfilling the ASAS criteria), while the 'imaging arm' predicted the progression of erosions with an odds ratio of 8. Moreover, in 24% of the patients in the 'imaging arm', all having BMO at the SIJ at baseline, the BMO disappeared without neither erosions nor ankylosis emerging., Conclusion: We found that the 'clinical arm' was a strong predictor for the progression of SIJ erosion, while the 'imaging arm' had a more modest prognostic value for structural progression., (© Japan College of Rheumatology 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Neck pain and headache are highly prevalent conditions and leading causes of disability worldwide. Although MRI is widely used in the management of these conditions, there is uncertainty about the clinical significance of cervical MRI findings in patients with neck pain or headache. Therefore, this study aims to investigate the association between cervical degenerative MRI findings and self-reported neck pain, neck disability, and headache., Methods: This study was a secondary analysis of a cohort of patients with low back pain aged 18-40 years recruited from a non-surgical outpatient spine clinic. The cervical MRI and outcome measures used in this analysis were collected at a four-year follow-up (2014-2017). Self-reported outcome measures included neck pain intensity, neck disability as measured by the Neck Disability Index, and headache as measured by a single NDI item. Cervical MRI findings included disc degeneration, disc contour changes, and vertebral endplate signal changes (VESC). Multivariable logistic regression analyses, adjusted for age and sex, were used to analyse the associations between MRI findings and neck pain, neck disability, and headache., Results: A total of 600 participants who underwent MRI and completed the relevant questionnaires at follow-up were included. The median age was 37 years (interquartile range 31-41) and 325 (54%) were female. Of the included participants, 181 (31%) had moderate or severe neck pain, 274 (59%) had moderate or severe neck disability, 193 (42%) reported headaches, and 211 (35%) had one or more cervical degenerative MRI findings. Cervical disc degeneration and disc contour changes were positively associated with moderate or severe neck pain with odds ratio 1.6 (95% CI 1.1-2.4) and 1.6 (1.1-2.3), respectively. VESC was associated with moderate or severe neck disability with odds ratio 3.3 (1.3-8.4). No statistically significant associations were found between the MRI findings assessed and headache., Conclusions: In this cross-sectional exploratory study, we found that cervical disc degeneration and disc contour changes were associated with neck pain, and VESC was associated with neck disability. None of the MRI findings were associated with headache. The results suggest that cervical degenerative changes may contribute to the aetiology of neck symptoms, but the associations are modest and cannot guide clinical decisions., (© 2023. Chiropractic and Osteopathic College of Australasia, European Academy of Chiropractic, The Royal College of Chiropractors, Nordic Institute of Chiropractic and Clinical Biomechanics and BioMed Central Ltd.)

Objectives: To review the available evidence on diagnostic imaging findings in knee and hip osteoarthritis (OA) as treatment effect modifiers in non-surgical OA interventions., Methods: MEDLINE, Embase and The Cochrane Central Register of Controlled Trials were searched from the earliest records published to 22 March 2022. Studies in knee and hip OA reporting subgroup analyses in randomised controlled trials with imaging findings as potential treatment effect modifiers were included. Studies were critically appraised using the Cochrane risk of bias tool and a subgroup analysis quality assessment., Results: Of 10 014 titles and abstracts screened, eight studies met the inclusion criteria, six on knee OA and two on hip OA. The studies investigated effect modifiers in exercise therapy, intra-articular injections and unloading shoes. Imaging findings assessed as potential treatment effect modifiers were radiographic OA severity, hip effusion (ultrasound), bone marrow lesions and meniscal pathology (MRI). Two studies fulfilled the methodological quality criteria for assessing effect modification. One reported that radiographic knee OA severity modified the effect of unloading shoes on walking pain. Those with more severe radiographic knee OA had a greater response to shoe inserts. One reported no interaction between radiographic OA severity or joint effusion and the effect of intraarticular injections of corticosteroid or hyaluronic acid in hip OA, indicating no difference in response in people with greater hip joint effusion or radiographic OA severity compared with those with less severe joint disease., Conclusion: Overall, methodological limitations and very few studies do not permit conclusions on diagnostic imaging findings as effect modifiers in non-surgical interventions in knee and hip OA.Radiographic severity of knee OA potentially modifies the effect of unloading shoes., Prospero Registration Number: CRD42020181934., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Magnetic resonance imaging (MRI) is commonly used in the management of low back pain (LBP). This review provides an overview of the clinical relevance of degenerative MRI findings in the lumbar spine. The association between degenerative MRI findings and LBP is relatively consistent at population level, but very little research exists on the prognostic value of MRI findings and based on the current evidence, MRI cannot be used to guide treatment. Lumbar spine MRI is only recommended for patients with progressive neurological deficits, suspicion of specific pathology or in absence of progress of conservative treatment.

Background: Evidence on prognostic factors associated with progression to total hip replacement (THR) in hip osteoarthritis (OA) is for the most patient- and disease-specific characteristics either conflicting or inconclusive. Therefore, the objectives of this study of participants with hip OA enrolled in a structured program of supervised education and exercise therapy were to describe the rate of THR and to identify prognostic factors for receiving THR within the following 2 years., Methods: Participants aged ≥ 45 years with hip OA enrolled in Good Life with osteoArthritis in Denmark (GLA:D®) from July 2014 to March 2017 were included. Potential prognostic factors included demographic and disease-specific baseline characteristics and measures of physical activity and quality of life (QoL). Information on THR was retrieved from The Danish National Patient Registry. A multivariable Cox proportional hazards model was developed., Results: Of 3657 included participants, 30% received a THR within 2 years. Of the 100 participants already wait-listed for THR, 60% had the procedure. Of 22 candidate prognostic factors, 14 were statistically significant for receiving THR. Factors associated with a faster rate of THR included being "male" (HR 1.43), having "self-reported radiographic hip OA" (HR 2.32), being "wait-listed for THR" (HR 2.17), and having a higher "pain intensity" (HR 1.01). In contrast, faster "walking speed" (HR 0.64), better "hip-related QoL" (HR 0.98), and having "three or more comorbidities" (HR 0.62) were predictive of a slower rate of THR., Conclusion: During the 2-year follow-up period, 30% of the cohort received a THR. Notably, 40% of those wait-listed for THR when entering the program did not receive THR within 2 years. A number of baseline prognostic factors for receiving THR were identified., (© 2021. The Author(s).)

Objectives: The objectives of this study were to asses (1) inter-rater and intrarater reliability of ultrasound imaging in patients with hip osteoarthritis, and (2) agreement between ultrasound and X-ray findings of hip osteoarthritis using validated Outcome Measures in Rheumatology ultrasound definitions for pathology., Design: An inter-rater and intrarater reliability study., Setting: A single-centre study conducted at a regional hospital., Participants: 50 patients >39 years of age referred for radiography due to hip pain and suspected hip osteoarthritis were included. Exclusion criteria were previous hip surgery in the painful hip, suspected fracture or malignant changes in the hip., Intervention: Bilateral ultrasound examinations (n=92) were performed continuously by two experienced operators blinded to clinical information and other imaging findings. After 4-6 weeks, one operator reassessed the images. X-rays were assessed by a third imaging specialist., Primary and Secondary Outcome Measures: Inter-rater and intrarater reliability and agreement between ultrasound imaging and X-ray were assessed using Cohen's ordinal kappa statistics for binary categorical variables and weighted kappa for ordered categorical variables., Results: Kappa values (κ) for inter-rater reliability were 0.9 and 0.8 for hip effusion/synovitis and osteoarthritis grading, respectively. For acetabular and femoral osteophytes, femoral cartilage changes and labrum changes κ ranged from 0.4 to 0.7. Intrarater reliability had κ equal or higher compared with inter-rater reliability. Agreement between ultrasound and X-ray findings ranged from κ=0.2 to κ=0.5., Conclusion: This study demonstrated substantial to almost perfect reliability on the most common ultrasound findings related to hip osteoarthritis and osteoarthritis grading. Agreement on the grade of osteoarthritis between ultrasound and X-ray was moderate. Overall, these results support ultrasound imaging as a reliable tool in the assessment of hip osteoarthritis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Sacroiliac (SI) joint bone marrow edema (BME) is considered to be pivotal in the detection of early spondyloarthritis. However, the link between BME and development of spondyloarthritis-related bone remodeling remains unclear. This study was undertaken to investigate the evolution of BME and structural lesions in the SI joints over time., Methods: Baseline and 4-year follow-up magnetic resonance imaging scans were conducted in 604 patients ages 18-40 years who were referred with low back pain to an outpatient spine clinic. Eight SI joint regions were scored for BME and categorized as absent, limited (<25% of subcortical bone region), intermediate (25-50%), or extensive (>50%). Structural lesions including erosions and fat lesions were scored as absent or present., Results: SI joint BME was seen at either time point (baseline or at 4 years) in 41% of participants but was persistent at both time points in only 16% of participants. Structural SI joint lesions developed according to the extent of BME at baseline: limited, intermediate, and extensive BME (as compared to absent BME) were independently associated with erosion at follow-up with odds ratios (ORs) of 3, 5, and 46, respectively, and with fat lesions (ORs 3, 7, and 33, respectively). In regions with limited and intermediate BME at baseline, 60% and 50% had resolved by follow-up, respectively, while only 2% and 7% had evolved into extensive BME by follow-up., Conclusion: While extensive SI joint BME was a strong independent predictor of development of structural lesions, limited and intermediate BME were mostly transient and only rarely evolved into extensive BME or structural lesions. These findings enhance our understanding of the natural development of SI joint lesions and indicate different progression patterns for limited/intermediate versus extensive BME, possibly due to different etiologies., (© 2019, American College of Rheumatology.)

The chronic joint inflammation in axial spondyloarthritis (axSpA) is characterized by infiltration of activated macrophages. The haptoglobin-hemoglobin receptor CD163 and the mannose receptor CD206 are strongly expressed on M2c and M2a macrophages, respectively. We measured the soluble forms of the receptors (sCD163 and sCD206) in plasma (PL) in two axSpA cohorts. All patients fulfil the 2009 Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axSpA and/or the 1984 modified New York criteria for ankylosing spondylitis. The first cohort included anti-TNF-α treated patients with active axSpA (n = 30); the second cohort included patients in early disease stages (n = 38). Plasma sCD163 and sCD206 were both within the reference interval of healthy controls (HC), but sCD163 decreased slightly during anti-TNF-α treatment [baseline: 1.49 mg/L (IQR: 1.22-1.77 mg/L, 12 weeks: 1.29 (IQR: 1.09-1.57) mg/L, 20 weeks: 1.25 (IQR: 0.99-1.75) mg/L, 52 weeks: 1.39 (IQR: 1.15-1.78) mg/L], while sCD206 increased [baseline: 0.17 (IQR: 0.13-0.21) mg/L, 12 weeks: 0.19 (0.16-0.23) mg/L, 20 weeks: 0.20 (0.14-0.24) mg/L, 52: 0.19 (IQR: 0.14-0.23) mg/L], pointing toward a shift in polarization of involved macrophages. Plasma levels of sCD206 proved significantly higher in patients with early disease stages and definite radiological sacroiliitis (n = 10). This was not the case for sCD163. A significant increase in response to anti-TNF-α treatment, could suggest sCD206 as a marker of response to anti-TNF-α treatment, however, the potential for the two macrophage markers as diagnostic and prognostic indicators of disease in axSpA is weak.

Objective: To investigate the association between magnetic resonance imaging (MRI) findings at the sacroiliac (SI) joints and vertebral endplates and pain characteristics assumed to be indicative of axial inflammation., Methods: Patients ages 18-40 years with persistent low back pain referred to an outpatient spine clinic participated, including an unknown proportion of axial spondyloarthritis patients. Data included MRI of the spine and SI joints and self-reported responses to questions covering the Calin, Berlin, Assessment of Spondyloarthritis International Society, and Bailly inflammatory back pain (IBP) definitions., Results: In the 1,020 included patients, 53% were women, and the median age was 33 years. Positive associations were found between the SI joint MRI findings and pain characteristics, odds ratios ranging from 1.4 to 2.7. SI joint bone marrow edema (BME) was associated with morning stiffness >60 minutes, and SI joint erosions with the Calin, Berlin, and Bailly IBP definitions, alternating buttock pain, and good response to nonsteroidal antiinflammatory drugs. SI joint fatty marrow deposition (FMD) was associated with insidious onset, and SI joint sclerosis with pain at night. In addition, the spinal MRI changes were associated with IBP, odds ratios ranging from 1.4 to 2.0; vertebral endplate BME was associated with morning stiffness, and vertebral endplate FMD with the Calin and Bailly IBP definitions, improvement with exercise, morning stiffness >30 minutes, and pain worst in the morning., Conclusion: The identified associations between inflammatory MRI findings and pain characteristics indicate that axial inflammation to some degree induces a specific pain pattern. Thus, the results add to knowledge of axial inflammatory processes. However, all identified associations were weak, which compromises the use of IBP as a marker of axial inflammation., (© 2017, American College of Rheumatology.)

Objective: To determine the reproducibility of evaluation of sacroiliac joint (SIJ) radiographs among readers with varying levels of experience, and to identify potential drivers of disagreement in classification among 5 predefined radiographic lesion types., Methods: The study sample consisted of 104 consecutive patients aged 18-40 with low back pain ≥ 3 months of duration who met the Assessment of SpondyloArthritis international Society (ASAS) definition for a positive SIJ magnetic resonance image, or were HLA-B27-positive and had ≥ 1 spondyloarthritis (SpA)-related clinical/laboratory feature according to the ASAS classification criteria for axial SpA. Seven blinded readers (2 musculoskeletal radiologists, 5 rheumatologists) classified pelvic radiographs according to the modified New York criteria (mNY) and recorded presence/absence of 5 lesion types in both SIJ: erosion, sclerosis, ankylosis, joint space widening, and joint space narrowing. Reproducibility of mNY classification among 21 reader pairs was assessed and potential drivers of disagreement were identified among 5 lesion types. A generalized linear mixed logistic regression model served to analyze to what extent discordance in lesion type was associated with discrepant mNY classification., Results: Mean κ values (percent concordance) were 0.39 (84.1%) for mNY classification over 21 reader pairs, 0.46 (79.8%) between 2 musculoskeletal radiologists, and 0.55 (86.5%) and 0.36 (77.9%) between the most experienced rheumatologist and the 2 radiologists. Erosion showed the lowest agreement (25%) among patients with discordant classification and gave the highest OR of 13.5 for disagreement., Conclusion: Reproducibility of radiographic SIJ classification in an SpA inception cohort was only fair to at best moderate among 7 readers with varying levels of experience, questioning the applicability of mNY in early SpA.

Background: The aim of this study was to investigate subgroups of magnetic resonance imaging (MRI) findings for the spine and sacroiliac joints (SIJs) using latent class analysis (LCA), and to investigate whether these subgroups differ in their demographic and clinical characteristics., Methods: The sample included 1037 patients aged 18-40 years with persistent low back pain (LBP). LCA was applied to MRI findings of the spine and SIJs. The resulting subgroups were tested for differences in self-reported demographic and clinical characteristics., Results: A five-class model was identified: Subgroup 1, 'No or few findings' (n = 116); Subgroup 2, 'Mild spinal degeneration' (n = 540); Subgroup 3, 'Moderate to severe spinal degeneration' (n = 229); Subgroup 4, 'Moderate to severe spinal degeneration with mild SIJ findings' (n = 68); and Subgroup 5, 'Mild spinal degeneration with moderate to severe SIJ findings' (n = 84). The two SIJ subgroups (Subgroups 4 and 5) had a higher median activity limitation score (Roland Morris Disability Questionnaire calculated as a proportional score: 65 (IQR 48-78)/65 (48-78)) compared with Subgroups 1-3 (48 (35-74)/57 (39-74)/57 (39-74)), a higher prevalence of women (68 % (95 % CI 56-79)/68 % (58-78)) compared with Subgroups 2 and 3 (51 % (47-55)/40 % (33-46)), a higher prevalence of being overweight (67 % (95 % CI 55-79)/53 % (41-65)) compared with Subgroup 1 (36 % (26-46)) and a higher prevalence of previous LBP episodes (yes/no: 81 % (95 % CI 71-91)/79 % (70-89)) compared with Subgroup 1 (58 % (48-67)). Subgroup 5 was younger than Subgroup 4 (median age 29 years (IQR 25-33) versus 34 years (30-37)) and had a higher prevalence of HLA-B27 (40 % (95 % CI 29-50)) compared with the other subgroups (Subgroups 1-4: 12 % (6-18)/7 % (5-10)/6 % (3-9)/12 % (4-20)). Across the subgroups with predominantly spinal findings (Subgroups 1-3), median age, prevalence of men, being overweight and previous LBP episodes were statistically significantly lower in Subgroup 1, higher in Subgroup 2 and highest in Subgroup 3., Conclusions: Five distinct subgroups of MRI findings in the spine and SIJs were identified. The results indicate that SIJ MRI findings not only can be seen as a part of the spondyloarthritis disease entity, but also are associated with age, gender and being overweight. Furthermore, the results indicate that LBP patients with SIJ MRI findings are more disabled compared with patients without SIJ MRI findings, and that moderate to severe spinal degeneration and/or SIJ MRI findings may be associated with recurrent pain.

Objective: The Assessment of SpondyloArthritis international Society (ASAS) has previously published criteria for spondyloarthritis (SpA). In the Spines of Southern Denmark cohort, which included patients with persistent low back pain and an unknown proportion of patients with SpA, our objectives were 1) to estimate the prevalence of magnetic resonance imaging (MRI) findings and clinical features included in the ASAS criteria for SpA and 2) to explore the associations between MRI findings and clinical features., Methods: We included patients ages 18-40 years with persistent low back pain who had been referred to the Spine Centre of Southern Denmark. We collected information on clinical features (including HLA-B27 and high-sensitivity C-reactive protein) and MRI findings in the spine and sacroiliac (SI) joints., Results: Of 1,020 included patients, 537 (53%) had at least 1 of the clinical features included in the ASAS criteria for SpA. Three clinical features were common-inflammatory back pain according to the ASAS criteria, a good response to nonsteroidal antiinflammatory drugs (NSAIDs), and family history of SpA. The prevalence of these features ranged from 15% to 17%. Sacroiliitis on MRI according to the ASAS definition was present in 217 patients (21%). Of those 217 patients, 91 (42%) had the minimum amount of bone marrow edema required according to the ASAS definition (a low bone marrow edema score). The presence of HLA-B27, peripheral arthritis, a good response to NSAIDs, and preceding infection were independently positively associated with MRI findings in the SI joints (odds ratios [ORs] of 1.9-9.0). The remaining 8 clinical features were not positively associated with MRI findings. Importantly, only age was independently associated with low bone marrow edema score at the SI joints (OR of 1.1 per year)., Conclusion: In this population, 53% had at least 1 clinical feature included in the ASAS criteria for SpA, and 21% had sacroiliitis according to the ASAS definition; furthermore, the associations between the clinical and imaging domains were inconsistent. The results indicate a need for further investigation of the importance of these findings in SpA, including investigation of the minimum requirements for defining sacroiliitis on MRI., (© 2016, American College of Rheumatology.)

Objective: To estimate the prevalence of degenerative and spondyloarthritis (SpA)-related magnetic resonance imaging (MRI) findings in the spine and sacroiliac joints (SIJs) and analyse their association with gender and age in persistent low back pain (LBP) patients., Methods: Degenerative and SpA-related MRI findings in the whole spine and SIJs were evaluated in Spine Centre patients aged 18-40 years with LBP., Results: Among the 1,037 patients, the prevalence of disc degeneration, disc contour changes and vertebral endplate signal (Modic) changes were 87 % (±SEM 1.1), 82 % (±1.2) and 48 % (±1.6). All degenerative spinal findings were most frequent in men and patients aged 30-40 years. Spinal SpA-related MRI findings were rare. In the SIJs, 28 % (±1.4) had at least one MRI finding, with bone marrow oedema being the most common (21 % (±1.3)). SIJ erosions were most prevalent in patients aged 18-29 years and bone marrow oedema in patients aged 30-40 years. SIJ sclerosis and fatty marrow deposition were most common in women. SIJ bone marrow oedema, sclerosis and erosions were most frequent in women indicating pregnancy-related LBP., Conclusion: The high prevalence of SIJ MRI findings associated with age, gender, and pregnancy-related LBP need further investigation of their clinical importance in LBP patients., Key Points: • The location of vertebral endplate signal changes supports a mechanical aetiology. • Several sacroiliac joint findings were associated with female gender and pregnancy-related back pain. • Sacroiliac joint bone marrow oedema was frequent and age-associated, indicating a possible degenerative aetiology. • More knowledge of the clinical importance of sacroiliac joint MRI findings is needed.

Background: The Back Pain Cohort of Southern Denmark (BaPa Cohort) was initiated with the aim of evaluating the clinical relevance of magnetic resonance imaging (MRI) in the diagnosis of early spondyloarthritis (SpA). In order to facilitate the collection of MRI data for this study, an electronic evaluation form was developed including both SpA-related and degenerative axial changes. The objective of the current study was to assess the intra- and inter-observer agreement of the MRI changes assessed., Methods: Three radiologists evaluated 48 MRI scans of the whole spine and the sacroiliac joints from a subsample of the BaPa Cohort, consisting of patients with non-specific low back pain and patients with different stages of SpA features. The spine was evaluated for SpA-related and degenerative MRI changes and the SIJ for SpA-related changes. Inter- and intra-observer agreements were calculated with kappa statistics. In the interpretation of the kappa coefficient, the standards for strength of agreement reported by Landis and Koch were followed., Results: A total of 48 patients, 40% men and mean age of 31 years (range 18-40 years), were evaluated once by all three readers and re-evaluated by two of the readers after 4-12 weeks. For MRI changes in the spine, substantial to almost perfect observer agreement was found for the location and the size of vertebral signal changes and for disc degeneration and disc contour. For the sacroiliac joints, substantial or almost perfect observer agreement was found for the grading of bone marrow oedema and fatty marrow deposition, the depth of bone marrow oedema and for subchondral sclerosis. Global assessment of the SpA diagnosis had substantial to almost perfect observer agreements., Conclusion: The acceptable agreement for key MRI changes in the spine and sacroiliac joints makes it possible to use these MRI changes in the BaPa Cohort study and other studies investigating MRI changes in patients with non-specific low back pain and suspected SpA.

Introduction: Magnetic resonance imaging (MRI) has been proven capable of showing inflammatory and structural changes in patients with spondyloarthritis (SpA) and has become widely used in the diagnosis of SpA. Despite this, no systematic reviews evaluate the diagnostic utility of MRI for SpA. Therefore, the objective of this systematic review was to determine the evidence for the utility of MRI in the clinical diagnosis of SpA. The aims were to identify which MRI findings are associated with the diagnosis of SpA and to quantify this association., Methods: MEDLINE and EMBASE were electronically searched. Inclusion criteria were cross-sectional or longitudinal case-control or cohort MRI studies. The studies required a group with either SpA or inflammatory back pain (IBP) and a non-case group without SpA or IBP. Each group required a minimum of 20 participants. The included articles had to report results containing raw numbers suitable for the construction of two-by-two tables or report results by sensitivity and specificity for cross-sectional studies or odds ratios, relative risk ratios, or likelihood ratios for longitudinal studies. Method quality was assessed by using criteria based on the QUADAS tool., Results: In total, 2,395 articles were identified in MEDLINE and EMBASE before November 2011. All articles were reviewed by title and abstract. Seventy-seven articles were reviewed by full text, and 10 met the inclusion criteria. Two were considered of high quality: one evaluated the sacroiliac joints, and the other, the spine. Because of the small number of high-quality studies, a meta-analysis was not performed. The two high-quality studies found a positive association between MRI findings (bone marrow edema, erosions, fat infiltrations, global assessment of sacroiliitis, and ankylosis) and the diagnosis of IBP and SpA., Conclusion: In this review, several MRI findings were found to be associated with SpA. However, because of the small number of high-quality studies, the evidence for the utility of MRI in the diagnosis of SpA must be considered limited. Therefore, caution should be taken to ensure that inflammatory and structural MRI findings are not interpreted as being more specific for SpA than is supported by research.