MRI-based synthetic CT: a new method for structural damage assessment in the spine in patients with axial spondyloarthritis - a comparison with low-dose CT and radiography.

OBJECTIVE: To investigate the ability of MRI-based synthetic CT (sCT), low-dose CT (ldCT) and radiography to detect spinal new bone formation (NBF) in patients with axial spondyloarthritis (axSpA). METHODS: Radiography of lumbar and cervical spine, ldCT and sCT of the entire spine were performed in 17 patients with axSpA. sCT was reconstructed using the BoneMRI application (V.1.6, MRIGuidance BV, Utrecht, NL), a quantitative three-dimensional MRI-technique based on a dual-echo gradient sequence and a machine learning processing pipeline that can generate CT-like MR images. Images were anonymised and scored by four readers blinded to other imaging/clinical information, applying the Canada-Denmark NBF assessment system. RESULTS: Mean scores of NBF lesions for the four readers were 188/209/37 for ldCT/sCT/radiography. Most NBF findings were at anterior vertebral corners with means 163 on ldCT, 166 on sCT and 35 on radiography. With ldCT of the entire spine as reference standard, the sensitivity to detect NBF was 0.67/0.13 for sCT/radiography; both with specificities >0.95. For levels that were assessable on radiography (C2-T1 and T12-S1), the sensitivity was 0.61/0.48 for sCT/radiography, specificities >0.90. For facet joints, the sensitivity was 0.46/0.03 for sCT/radiography, specificities >0.94. The mean inter-reader agreements (kappa) for all locations were 0.68/0.58/0.56 for ldCT/sCT/radiography, best for anterior corners. CONCLUSION: With ldCT as reference standard, MRI-based sCT of the spine showed very high specificity and a sensitivity much higher than radiography, despite limited reader training. sCT could become highly valuable for detecting/monitoring structural spine damage in axSpA, not the least in clinical trials.

Changes of inflammation in patients with psoriatic arthritis after high intensity interval training assessed by ultrasound and MRI, a randomized controlled trial.

BACKGROUND: In psoriatic arthritis (PsA) there is a theoretical risk of increased disease activity related to strenuous physical activity, including exercise. We evaluated the effect of high intensity interval training (HIIT) on objective measures of inflammation in PsA assessed by ultrasound (US) of peripheral joints and entheses, and by bone marrow edema (BME) on MRI of the sacroiliac joints (SIJ) and spine. METHODS: We randomly assigned 67 PsA patients to an intervention group that performed structured HIIT for 11 weeks, or to a control group instructed not to change their physical exercise habits. Outcome measures included US evaluation of the total cohort and MRI in a subgroup of 41; both assessed at 3 months. We calculated the proportions with an increased US B-mode and power-doppler (PD) signal of joints and entheses and Spondyloarthritis-Research-Consortium-of-Canada (SPARCC)-BME score of the SIJ and spine for both groups. RESULTS: Proportions with an increased US B-mode score of the joints were 32% and 28% in HIIT and control groups, respectively. Corresponding proportions of PD scores of the joints were 7% and 10% and PD scores of entheses were 32% and 31%. The proportions with increased MRI BME of the SIJ were 6% in the HIIT group and 10% in the control group. Corresponding proportions were 6% and 5% for the MRI BME of the spine. CONCLUSION: In PsA patients with a low to moderate disease activity, there was no clear evidence of objectively measured increased inflammation after HIIT, as evaluated by US and MRI. TRIAL REGISTRATION: ClinicalTrials.gov NCT02995460 (16/12/2016).

MRI lesions of the spine in patients with axial spondyloarthritis: an update of lesion definitions and validation by the ASAS MRI working group.

OBJECTIVES: Spinal MRI is used to visualise lesions associated with axial spondyloarthritis (axSpA). The ASAS MRI working group (WG) updated and validated the definitions for inflammatory and structural spinal lesions in the context of axSpA. METHODS: After review of the existing literature on all possible types of spinal MRI pathologies in axSpA, the group (12 rheumatologists and two radiologists) consented on the required revisions of lesion definitions compared with the existing nomenclature of 2012. In a second step, using 62 MRI scans from the ASAS classification cohort, the proposed definitions were validated in a multireader campaign by global (absent/present) and detailed (inflammation and structural) lesion assessment at the vertebral corner (VC), vertebral endplate, facet joints, transverse processes, lateral and posterior elements. Intraclass correlation coefficient (ICC) was used for analysis. RESULTS: Revisions were made for both inflammatory (bone marrow oedema, BMO) and structural (fat, erosion, bone spur and ankylosis) lesions, including localisation (central vs lateral), extension (VC vs vertebral endplate) and extent (minimum number of slices needed), while new definitions were suggested for the type of lesion based on lesion maturity (VC monomorphic vs dimorphic). The most reliably assessed lesions were VC fat lesion and VC monomorphic BMO (ICC (mean of all 36 reader pairs/overall 9 readers): 0.91/0.92; 0.70/0.67, respectively. CONCLUSIONS: The lesion definitions for spinal MRI lesions compatible with SpA were updated by consensus and validated by a group of experienced readers. The lesions with the highest frequency and best reliability were fat and monomorphic inflammatory lesions at the VC.

Morphological characteristics of sacroiliac joint MRI lesions in axial spondyloarthritis and control subjects.

OBJECTIVES: To investigate SI joint MRI inflammation, structural and degenerative lesion characteristics in patients with axial spondyloarthritis (axSpA) and various control groups. METHODS: Patients with axSpA (n = 41) and lumbar disc herniation (n = 25), women with (n = 46) and without (n = 14) post-partum (childbirth within 4-16 months) buttock/pelvic pain, cleaning assistants (n = 26), long-distance runners (n = 23) and healthy men (n = 29) had MRI of the SI joints prospectively performed. MRI lesions were assessed on nine slices covering the cartilaginous compartment by two experienced readers according to the definitions of the Spondyloarthritis Research Consortium of Canada SI joint inflammation and structural scores, and were evaluated according to depth and extent. Other morphological characteristics were also analysed. RESULTS: Total depth scores for bone marrow oedema (BME) and fat lesion (FAT) and total extent score for erosion were statistically significantly highest in axSpA, while scores for sclerosis were numerically highest in women with post-partum pain. Maximum BME depth >10 mm was frequently and exclusively found in axSpA and post-partum women (39% vs 14-17%) while FAT depth >5 mm was predominantly found in axSpA (76% vs 0-10%). Erosions were primarily seen in axSpA, especially when extensive (≥4 or confluent; 17% vs 0%). Capsulitis was absent in non-axSpA groups. BME and FAT in the ligamentous compartment were primarily found in axSpA (17/22% vs 0/2% in non-axSpA groups). In non-axSpA, osteophytes (axSpA vs non-axSpA: 0% vs 3-17%) and vacuum phenomenon (7% vs 30-66%) were more frequent, and the joint space was wider [mean (s.d.) 1.5 (0.9) vs 2.2 (0.5) mm]. CONCLUSIONS: FAT depth >5 mm, but not BME depth >10 mm, could almost differentiate axSpA patients from all other groups. When excluding post-partum women, BME >5 mm and erosion were highly specific for axSpA.

Do tender joints in active psoriatic arthritis reflect inflammation assessed by ultrasound and magnetic resonance imaging?

OBJECTIVE: To investigate the association between clinical joint tenderness and intra- and periarticular inflammation as assessed by ultrasound and MRI in patients with active PsA and to explore if the associations differ according to patient-reported outcomes (PROs) and structural damage. METHODS: Forty-one patients with active PsA and hand involvement had 76/78 joints examined for swelling/tenderness and ultrasound and MRI of 24 and 12 finger joints, respectively. Synovitis, tenosynovitis, periarticular inflammation and erosions were assessed using OMERACT definitions and scoring systems. Correlation between imaging inflammation sum-scores (intra-and periarticular) and tender/swollen joint counts were calculated using Spearman's rho, agreement at joint level was examined using prevalence and bias adjusted kappa (PABAK). Subgroup analyses explored the influence of PROs and radiographic erosive disease on these associations. RESULTS: No significant correlations were found between tender or swollen joint counts and imaging inflammation sum-scores (rho = -0.31-0.38). In patients with higher level of overall pain, disability and lower self-reported mental health, a tendency towards negative correlations were found. At joint level, intra- and periarticular imaging inflammatory lesions had slight agreement with joint tenderness (PABAK = 0.02-0.19) and slight to moderate with swelling (PABAK = 0.16-0.54). For tender joints, agreement with imaging inflammation was even weaker in patients with either high overall pain scores, high disability scores, and/or non-erosive disease. CONCLUSION: Joint tenderness had low association with imaging signs of inflammation in PsA patients, particularly in patients with high self-reported pain, disability and low mental health, indicating that tenderness is influenced by other parameters than local inflammation.

Tapering of TNF inhibitors in axial spondyloarthritis in routine care - 2-year clinical and MRI outcomes and predictors of successful tapering.

OBJECTIVES: In a 2-year follow-up study of patients with axial spondyloarthritis (axSpA) in clinical remission who tapered TNF inhibitor (TNFi) treatment according to a clinical guideline, we aimed to investigate the proportion who successfully tapered/discontinued therapy and baseline predictors thereof. The proportion regaining clinical remission after flare and the progression on MRI/radiography were also assessed. METHODS: One-hundred-and-nine patients (78 [72%]/31 [28%] receiving standard and reduced dose, respectively) in clinical remission (BASDAI < 40, physician global score < 40) and no signs of disease activity the previous year tapered TNFi as follows: to two-thirds of standard dose at baseline, half at week 16, one-third at week 32 and discontinuation at week 48. Patients experiencing clinical, BASDAI or MRI flare (predefined criteria) stopped tapering and escalated to previous dose. Prediction analyses were performed by multivariable regression. RESULTS: One hundred and six patients (97%) completed 2 years' follow-up; 55 patients (52%) had successfully tapered: 23 (22%) receiving two-thirds, 15 (14%) half, 16 (15%) one-third dose and 1 (1%) discontinued. In patients at standard dose at baseline (n = 78), lower physician global score was the only independent predictor of successful tapering (odds ratio [OR] = 0.79 [95% CI: 0.64, 0.93]; P = 0.003). In the entire patient group lower physician global score (OR = 0.86 [0.75, 0.98]; P = 0.017), lower Spondyloarthritis Research Consortium of Canada (SPARCC) Sacroiliac Joint Erosion score (OR = 0.78 [0.57, 0.98]; P = 0.029) and current smoker (OR = 3.28 [1.15, 10.57]; P = 0.026) were independent predictors of successful tapering. At 2 years, 97% of patients were in clinical remission. Minimal changes in imaging findings were observed. CONCLUSION: After 2 years following a clinical guideline, 52% of patients with axSpA in clinical remission had successfully tapered TNFi, only 1% discontinued. Baseline physician global score was an independent predictor of successful tapering.

Central reader evaluation of MRI scans of the sacroiliac joints from the ASAS classification cohort: discrepancies with local readers and impact on the performance of the ASAS criteria.

OBJECTIVES: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group conducted a multireader exercise on MRI scans from the ASAS classification cohort to assess the spectrum and evolution of lesions in the sacroiliac joint and impact of discrepancies with local readers on numbers of patients classified as axial spondyloarthritis (axSpA). METHODS: Seven readers assessed baseline scans from 278 cases and 8 readers assessed baseline and follow-up scans from 107 cases. Agreement for detection of MRI lesions between central and local readers was assessed descriptively and by the kappa statistic. We calculated the number of patients classified as axSpA by the ASAS criteria after replacing local detection of active lesions by central readers and replacing local reader radiographic sacroiliitis by central reader structural lesions on MRI. RESULTS: Structural lesions, especially erosions, were as frequent as active lesions (≈40%), the majority of patients having both types of lesions. The ASAS definitions for active MRI lesion typical of axSpA and erosion were comparatively discriminatory between axSpA and non-axSpA. Local reader overcall for active MRI lesions was about 30% but this had a minor impact on the number of patients (6.4%) classified as axSpA. Substitution of radiography with MRI structural lesions also had little impact on classification status (1.4%). CONCLUSION: Despite substantial discrepancy between central and local readers in interpretation of both types of MRI lesion, this had a minor impact on the numbers of patients classified as axSpA supporting the robustness of the ASAS criteria for differences in assessment of imaging.

The utility of magnetic resonance imaging lesion combinations in the sacroiliac joints for diagnosing patients with axial spondyloarthritis. A prospective study of 204 participants including post-partum women, patients with disc herniation, cleaning staff, runners and healthy persons.

OBJECTIVES: To investigate the diagnostic utility of different combinations of SI joint MRI lesions for differentiating patients with axial SpA (axSpA) from other conditions with and without buttock/pelvic pain. METHODS: A prospective cross-sectional study included patients with axSpA (n = 41), patients with lumbar disc herniation (n = 25), women with (n = 46) and without (n = 14) post-partum (birth within 4-16 months) buttock/pelvic pain and cleaning assistants (n = 26), long-distance runners (n = 23) and healthy men (n = 29) without pain. Two independent readers assessed SI joint MRI lesions according to the Spondyloarthritis Research Consortium of Canada MRI definitions and pre-defined MRI lesion combinations with bone marrow oedema (BME) and fat lesions (FAT), respectively. Statistical analyses included the proportion of participants with scores above certain thresholds, sensitivity, specificity, positive and negative predictive values and likelihood ratios. RESULTS: BME adjacent to the joint space (BME@joint space) was most frequent in axSpA (63.4%), followed by women with post-partum pain (43.5%), but was present in nearly all groups. BME adjacent to fat lesions (BME@FAT) and BME adjacent to erosions (BME@erosion) were only present in axSpA patients and in women with post-partum pain, but scores ≥3 and ≥4, respectively, were only seen in axSpA patients. FAT@erosion was exclusively recorded in axSpA patients. FAT@joint space and FAT@sclerosis were present in most groups, but with higher scores in the axSpA group. CONCLUSION: BME@joint space and FAT@joint space were frequent in axSpA but also in other conditions, reducing the diagnostic utility. FAT@erosion, and BME@FAT, BME@erosion and FAT@sclerosis above certain thresholds, were exclusively seen in axSpA patients and may thus have diagnostic utility in the differentiation of axSpA from other conditions.

MRI lesions in the sacroiliac joints of patients with spondyloarthritis: an update of definitions and validation by the ASAS MRI working group.

OBJECTIVES: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group (WG) was convened to generate a consensus update on standardised definitions for MRI lesions in the sacroiliac joint (SIJ) of patients with spondyloarthritis (SpA), and to conduct preliminary validation. METHODS: The literature pertaining to these MRI lesion definitions was discussed at three meetings of the group. 25 investigators (20 rheumatologists, 5 radiologists) determined which definitions should be retained or required revision, and which required a new definition. Lesion definitions were assessed in a multi-reader validation exercise using 278 MRI scans from the ASAS classification cohort by global assessment (lesion present/absent) and detailed scoring (inflammation and structural). Reliability of detection of lesions was analysed using kappa statistics and the intraclass correlation coefficient (ICC). RESULTS: No revisions were made to the current ASAS definition of a positive SIJ MRI or definitions for subchondral inflammation and sclerosis. The following definitions were revised: capsulitis, enthesitis, fat lesion and erosion. New definitions were developed for joint space enhancement, joint space fluid, fat metaplasia in an erosion cavity, ankylosis and bone bud. The most frequently detected structural lesion, erosion, was detected almost as reliably as subchondral inflammation (κappa/ICC:0.61/0.54 and 0.60/0.83) . Fat metaplasia in an erosion cavity and ankylosis were also reliably detected despite their low frequency (κappa/ICC:0.50/0.37 and 0.58/0.97). CONCLUSION: The ASAS-MRI WG concluded that several definitions required revision and some new definitions were necessary. Multi-reader validation demonstrated substantial reliability for the most frequently detected lesions and comparable reliability between active and structural lesions.

The Pathogenesis of Ankylosing Spondylitis: an Update.

PURPOSE OF REVIEW: Ankylosing spondyloarthritis (AS) is a chronic inflammatory disease that involves the axial joints and entheses. Extra-spinal manifestations such as anterior uveitis, psoriasis, and colitis also occur frequently. This review on the pathogenesis of AS includes an update on the recent discoveries within the field. RECENT FINDINGS: HLA-B*27 is still considered of major importance in the pathogenesis, and it has recently been shown to profoundly affect the gut microbiome and its metabolites and the handling of bacteria during infection. Biochemical and biophysical properties of HLA-B*27 influence its ability to misfold, to induce an endoplasmic reticulum stress response, and to promote autophagy/unfolded protein responses (UPR). HLA-B*27 free heavy chains may induce inflammation through T cells, NK cells, and myeloid cells. Induction of UPR genes results in release of tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), IL-23, and interferon-γ and increase in T helper (Th) 17 cells. Several other HLA-B and non-B molecules have been associated with AS, although their role in the pathogenesis is unknown. Genotypes of endoplasmic reticulum aminopeptidases (ERAP) 1 and 2 have been associated with alterations in the antigenic pool expressed by HLA-B*27 molecules. In the gut, innate immune cells type 3 (ILC3) influence T cell expression of IL-17 and IL-22. Gamma-delta (γ/δ) T cells are induced by IL-23 to produce IL-17. IL-7 induces mucosa-associated invariant T (MAIT) cells to produce IL-17. Besides the microbiome, zonulin may be important through its effects on the permeability of tight junctions in the intestinal epithelial barrier.

Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group.

OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording of the existing definition was examined in detail and the data and a draft proposal were presented to and voted on by the ASAS membership. RESULTS: The clear presence of bone marrow oedema on MRI in subchondral bone is still considered to be the defining observation that determines the presence of active sacroiliitis. Structural damage lesions seen on MRI may contribute to a decision by the observer that inflammatory lesions are genuinely due to SpA but are not required to meet the definition. The existing definition was clarified adding guidelines and images to assist in the application of the definition. CONCLUSION: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility when used for classification purposes.

Enthesitis in patients with psoriatic arthritis, axial spondyloarthritis and healthy subjects assessed by 'head-to-toe' whole-body MRI and clinical examination.

OBJECTIVES: To investigate the ability of whole-body MRI (WBMRI) to detect axial and peripheral enthesitis in patients with psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA), and in healthy subjects (HS). Furthermore, to develop MRI enthesitis indices based on WBMRI and validate these by use of clinical measures of disease activity. METHODS: Prospective cross-sectional study of patients with PsA (n=18) and axSpA (n=18) with moderate to high disease activity, and HS (n=12). Enthesitis at 35 individual sites located at upper and lower limbs, chest and pelvis were evaluated by WBMRI and clinical examination, and compared. Three new WBMRI enthesitis indices were developed. RESULTS: WBMRI allowed evaluation of 888 (53%) of 1680 sites investigated, and 19 (54%) of 35 entheses had a readability >70%. The percentage agreement between WBMRI and clinical enthesitis was 49-100%, when compared at the level of the individual entheses. Enthesitis on WBMRI was observed in 148 (17%) of the entheseal sites, and was frequently present at greater trochanters (55%) and Achilles (43%) and supraspinate (23%) tendon insertions in patients and HS. At the first mentioned two locations enthesitis often appeared without clinical signs of enthesitis. Patients and HS differed significantly in one of the new WBMRI enthesitis scores. Patients and HS differed significantly in one of the new WBMRI enthesitis scores, and this score correlated weakly with BASDAI question 4 (tenderness in relation to entheses), BASDAI and patient global (ρ=0.29-0.31, p<0.05). CONCLUSIONS: WBMRI is a promising new imaging modality for evaluation of enthesitis in patients with PsA and axSpA, but requires further investigation before clinical use.

Head-to-toe whole-body MRI in psoriatic arthritis, axial spondyloarthritis and healthy subjects: first steps towards global inflammation and damage scores of peripheral and axial joints.

OBJECTIVES: By whole-body MRI (WBMRI), we aimed to examine the frequency and distribution of inflammatory and structural lesions in PsA patients, SpA patients and healthy subjects (HSs), to introduce global WBMRI inflammation/damage scores, and to assess WBMRI's reproducibility and correlation with conventional MRI (convMRI). METHODS: WBMRI (3.0-T) of patients with peripheral PsA (n = 18) or axial SpA (n = 18) and of HS (n = 12) was examined for proportion of evaluable features (readability) and the presence and pattern of lesions in axial and peripheral joints. Furthermore, global WBMRI scores of inflammation and structural damage were constructed, and WBMRI findings were compared with clinical measures and convMRI (SpA/HS: spine and SI joints; PsA/HS: hand). RESULTS: The readability (92-100%) and reproducibility (intrareader intraclass correlation coefficient: 0.62-1.0) were high in spine/SI joint, but lower in the distal peripheral joints. Wrists, shoulders, knees, ankles and MTP joints were most commonly involved, with frequency of synovitis > bone marrow oedema (BMO) > erosion. WBMRI global BMO scores of peripheral and axial joints were higher in PsA {median 7 [interquartile range (IQR) 3-15]} and SpA [8 (IQR 2-14)] than in HSs [2.5 (IQR 1-4.5)], both P < 0.05. WBMRI global structural damage scores (erosion, fat infiltration and ankylosis) were higher in SpA [7 (IQR 3-12)] than HSs [1.5 (IQR 0-4.5)], P = 0.012. Correlations between WBMRI and convMRI spine and SI joint scores were ρ = 0.20-0.78. CONCLUSION: WBMRI allows simultaneous assessment of peripheral and axial joints in PsA and SpA, and the distribution of inflammatory and structural lesions and global scores can be determined. The study strongly encourages further development and longitudinal testing of WBMRI techniques and assessment methods in PsA and SpA.

Influence of field strength, coil type and image resolution on assessment of synovitis by unenhanced MRI--a comparison with contrast-enhanced MRI.

OBJECTIVES: To explore if the reliability of synovitis assessment by unenhanced MRI is influenced by different MRI field-strengths, coil types and image resolutions in RA patients. METHODS: Forty-one RA patients and 12 healthy controls underwent hand MRI (wrist and 2(nd)--5(th) metacarpophalangeal joints) at 4 different field-strengths (0.23 T/0.6 T/1.5 T/3.0 T) on the same day. Seven protocols using a STIR sequence with different field-strengths, coils (flex coils/dedicated phased-array extremity coils) and resolution were applied and scored blindly for synovitis (OMERACT-RAMRIS method). A 1.5 T post-contrast T1-weighted sequence was used as gold standard reference. RESULTS: Fair-good agreement (ICC=0.38--0.72) between the standard reference and the different STIR protocols (best agreement with extremity coil and small voxel size at 1.5 T). The accuracy for presence/absence of synovitis was very high per person (0.80--1.0), and moderate-high per joint (0.63--0.85), whereas exact agreements on scores were moderate (0.50--0.66). The intrareader agreement (15 patients and 3 controls) on presence/absence of synovitis was very high (0.87--1.0). CONCLUSIONS: Unenhanced MRI using STIR sequence is only moderately reliable for assessing hand synovitis in RA, when contrast-enhanced MRI is considered the gold standard reference. Contrast injection, field strength and coil type influence synovitis assessment, and should be considered before performing MRI in clinical trials and practice. KEY POINTS: • STIR is only moderately reliable for synovitis assessment, compared with post-contrast-T1-w. • Contrast injection, field strength, and coil type influence synovitis assessment. • Contrast injection is recommended for reliable and reproducible hand synovitis assessment.

Magnetic resonance imaging for diagnosing, monitoring and prognostication in psoriatic arthritis.

Psoriatic arthritis (PsA) is a chronic systemic, inflammatory disease associated with skin psoriasis. PsA may be difficult to assess with clinical examination and blood tests because of its complex and multifaceted clinical presentation. Magnetic resonance imaging (MRI) can visualise all peripheral and axial joints and entheses involved in PsA, and allow the rheumatologist to assess inflammation and structural damage in detail. In the present paper, we provide a brief overview of MRI to diagnose, monitor and prognosticate in PsA in clinical care.

Recent Advances in Imaging of the Axial Skeleton in Spondyloarthritis for Diagnosis, Assessment of Treatment Effect, and Prognostication.

In the last few years, many studies have investigated the role of imaging for improved diagnosis, assessment of treatment effects, and determining prognosis in patients with axial spondyloarthritis (SpA). Recent research has primarily focused on the utility of magnetic resonance imaging (MRI) for improved diagnosis of patients with non-radiographic axial SpA, and in particular on the classification utility of the MRI criteria as defined by the Assessment of Spondyloarthritis International Society (ASAS). New and more sensitive methods for evaluation of MRI of the sacroiliac joints have been developed and have provided insight into effects of treatment on structural progression and the interrelationships between different lesions visualized by MRI. This review gives an overview of the recent advances in imaging of the axial skeleton in axial SpA from a clinical perspective.

Whole-body MRI assessment of disease activity and structural damage in rheumatoid arthritis: first step towards an MRI joint count.

OBJECTIVE: The aim of this study was to investigate the ability of whole-body MRI (WBMRI) to visualize inflammation [synovitis, bone marrow oedema (BME) and enthesitis] and structural damage in patients with RA. METHODS: The 3T WBMR images were acquired in a head-to-toe scan in 20 patients with RA and at least one swollen or tender joint. Short Tau Inversion Recovery and pre- and post-contrast T1-weighted images were evaluated for readability and the presence/absence of inflammation (synovitis, BME and enthesitis) and structural damage (erosions and fat infiltrations) in 76 peripheral joints, 30 entheseal sites and in the spine. RESULTS: The readability was >70% for all individual joints, except for the most peripheral joints of the hands and feet. Synovitis was most frequent in the wrist, first tarsometatarsal, first CMC joints and glenohumeral joints (67-61%); BME in the wrist, CMC, acromioclavicular and glenohumeral joints (45-35%) and erosions in the wrist, MTP and CMC joints (19-16%). Enthesitis at ≥ 1 site was registered in 16 patients. BME was frequently seen in the cervical (20%) but not the thoracic and lumbar spine, while fat infiltrations and erosions were rare. The intrareader agreement was high (85-100%) for all pathologies. The agreement between WBMRI and clinical findings was low. CONCLUSION: Peripheral and axial inflammation and structural damage at joints and entheses was frequently identified by WBMRI, and more frequently than by clinical examination. WBMRI is a promising tool for evaluation of the total inflammatory load of inflammation (an MRI joint count) and structural damage in RA patients.

Bone marrow oedema assessment by magnetic resonance imaging in rheumatoid arthritis wrist and metacarpophalangeal joints: the importance of field strength, coil type and image resolution.

OBJECTIVE: The aim of this study was to examine the influence of different MRI unit field strengths, coil types and image resolutions on the OMERACT RA MRI scoring system (RAMRIS) of bone marrow oedema (BME) and image quality. METHODS: Forty-one patients and 12 healthy controls participated in this cross-sectional study. Coronal short tau inversion recovery (STIR) and T1-weighted sequences were obtained at 0.23, 0.6, 1.5 and 3T using flex coils (Flex). Additional STIR sequences were obtained with phased array extremity coils (Extr) (at 0.6 and 1.5T) and higher resolution (at 1.5T). In otal, 338 STIR image sets were anonymized and scored according to RAMRIS and parameters of image quality were measured. RESULTS: The BME sum scores were similar overall when comparing the different MRI units, coil types and voxel sizes, yet significantly higher at the higher resolution of 1.5T Extr compared with 0.23T Flex (P = 0.004), 0.6T Flex (P = 0.03), 1.5T Flex (P = 0.05) and 3T Flex (P = 0.001). Mean differences were relatively minor (0-3.5). Intrareader reliability of BME scores was high [intraclass correlation coefficient ≥ 0.90 for all except 0.23T (0.81) and percentage exact agreement 81-88%]. The smallest detectable difference was better at 0.6, 1.5 and 3T (9-29% of maximum value) than at 0.23T (40%). Image quality was lowest at 0.23T. CONCLUSION: No major, consistent differences were found between BME scores using STIR sequences obtained at different field strengths, coil types and image resolutions, suggesting that these are equally suited for assessment of BME in RA. However, parameters of image quality and intrareader reliability (favouring 0.6, 1.5 and 3T) should be considered when selecting the MRI acquisition strategy.

No overall damage progression despite persistent inflammation in adalimumab-treated psoriatic arthritis patients: results from an investigator-initiated 48-week comparative magnetic resonance imaging, computed tomography and radiography trial.

OBJECTIVE: In a comparative conventional MRI, dynamic contrast-enhanced (DCE)-MRI, CT and radiography study, the authors aimed to monitor whether inflammation is reduced or even eliminated and damage halted in PsA patients receiving anti-TNF therapy. METHODS: A 48-week prospective open-label investigator-initiated trial of 41 biologic-naive patients treated with 40 mg adalimumab every other week. Hand CT, MRI (according to the PsA MRI scoring system method) and radiography (Sharp-van der Heijde method) were obtained at weeks 0, 6 (only MRI), 24 and 48. Clinical response was assessed by the PsA Response Criteria (PsARC). RESULTS: In the 23 PsARC responders at week 48, significant decreases from baseline in MRI synovitis (mean -2.0, P < 0.05), bone marrow oedema (BMO) (-1.3, P < 0.05), flexor tenosynovitis (-2.1, P < 0.05) and total inflammation (-6.0, P < 0.005) were observed. However, MRI signs of inflammation remained present (week 48 total inflammation score median = 9). Several DCE-MRI parameters also decreased (P < 0.05) and were correlated (ρ = 0.62) with conventional MRI total inflammation score. No statistically significant changes in bone erosion or proliferation scores were observed. With CT as the standard reference for detecting bone erosions/proliferations, sensitivity, specificity and accuracy were 100%/40%, 83%/93% and 84%/86%, respectively, for MRI, whereas corresponding values for radiography were 17%/26%, 98%/96%, and 93%/87%, respectively. Erosive progression as assessed by CT was found in 6 of 480 joints and baseline BMO was predictive (relative risk 10, 95% CI 2.1, 49). CONCLUSION: MRI signs of inflammation decrease, but do not disappear, during anti-TNF-α therapy. No overall changes in bone erosions or proliferations were observed. On joint-level baseline MRI, BMO was related to subsequent erosive progression detected by CT. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov/, NCT01465438.