Cartilage Imaging: Techniques and Developments.

Cartilage degeneration is one of the most common chronic age-related joint disorders leading to pain and reduced joint motion. The increasing prevalence of osteoarthritis requires accurate cartilage imaging, both clinically and in research. Detailed cartilage imaging is also necessary for traumatic cartilage lesions and for pre- and postoperative assessment of cartilage repair procedures. Although still widely used, conventional radiography bears significant limitations because it assesses cartilage indirectly by joint space width. Magnetic resonance imaging (MRI) enables direct visualization of cartilage damage along with other concomitantly affected joint tissues. Several semiquantitative grading systems and volumetric analysis methods exist to assess cartilage damage and cartilage repair on MRI. Quantification of hyaline and fibrocartilage biochemical composition is possible with novel MRI methods such as T2- and T1ρ-mapping, delayed gadolinium-enhanced MRI of cartilage, glycosaminoglycan chemical exchange saturation transfer, and sodium imaging, along with quantitative computed tomography arthrography. These techniques provide promising quantitative imaging biomarkers that can detect early cartilage changes before morphological alterations occur.

Good clinical and radiographic outcome of cementless metal metaphyseal sleeves in total knee arthroplasty.

Background and purpose - The number of revision total knee arthroplasties (TKA) is continuously increasing, leading to a growing need for reliable management of metaphyseal bone loss. We evaluated patients operated with a TKA using metal metaphyseal sleeves for bone defects with a minimum 5-year follow-up. Patients and methods - 37 patients had been operated on. 3 patients died and 3 patients were lost during follow-up. Of the 31 remainders (20 women), 9 had been operated on with a primary TKA and 22 with a revision TKA at the index surgery. The mean age at surgery was 69 (54-89) years and the mean follow-up time was 7.4 (5-12) years. Bone defects were classified according to the Anderson Orthopaedic Research Institute classification (tibia: type I n = 9, type II n = 5 and type III n = 17; femur: type I n = 12, type II n = 3 and type III n = 16). Results - At final follow-up one-third experienced an improvement concerning walking aids and walking distance. Except for 1 patient, all had full extension and a mean knee flexion of 110 (90-140) degrees. VAS pain at rest was 13 (SD 25) and on movement 30 (SD 31). 7 patients were reoperated due to: infection (n = 4), periprosthetic fracture (n = 1), skin necrosis (n = 1), and wound rupture (n = 1). The cumulative 5-year survival rate for reoperation was 77% (CI 63-92) and for revision 97% (CI 91-100). At the time of final follow-up, the sleeves showed good osseointegration with no signs of progressive radiolucency or migration. Interpretation - Titanium sleeves are a promising option in managing difficult cases with metaphyseal bone defects in TKA, providing a stable construct with good medium-term radiographic outcome.

Comparison of metal ion concentrations and implant survival after total hip arthroplasty with metal-on-metal versus metal-on-polyethylene articulations.

Background and purpose - Large metal-on-metal (MoM) articulations are associated with metal wear and corrosion, leading to increased metal ion concentrations and unacceptable revision rates. There are few comparative studies of 28-mm MoM articulations with conventional metal-on-polyethylene (MoP) couplings. We present a long-term follow-up of a randomized controlled trial comparing MoM versus MoP 28-mm articulations, focused on metal ions and implant survival. Patients and methods - 85 patients with a mean age of 65 years at surgery were randomized to a MoM (Metasul) or a MoP (Protasul) bearing. After 16 years, 38 patients had died and 4 had undergone revision surgery. 13 patients were unavailable for clinical follow-up, leaving 30 patients (n = 14 MoM and n = 16 MoP) for analysis of metal ion concentrations and clinical outcome. Results - 15-year implant survival was similar in both groups (MoM 96% [95% CI 88-100] versus MoP 97% [95% CI 91-100]). The mean serum cobalt concentration was 4-fold higher in the MoM (1.5 µg/L) compared with the MoP cohort (0.4 µg/L, p < 0.001) and the mean chromium concentration was double in the MoM (2.2 µg/L) compared with the MoP cohort (1.0 µg/L, p = 0.05). Mean creatinine levels were similar in both groups (MoM 93 µmol/L versus MoP 92 µmol/L). Harris hip scores differed only marginally between the MoM and MoP cohorts. Interpretation - This is the longest follow-up of a randomized trial on 28-mm MoM articulations, and although implant survival in the 2 groups was similar, metal ion concentrations remained elevated in the MoM cohort even in the long term.

A new low-dose multi-phase trauma CT protocol and its impact on diagnostic assessment and radiation dose in multi-trauma patients.

PURPOSE: Computed tomography (CT) examinations, often using high-radiation dosages, are increasingly used in the acute management of polytrauma patients. This study compares a low-dose polytrauma multi-phase whole-body CT (WBCT) protocol on a latest generation of 16-cm detector 258-slice multi-detector CT (MDCT) scanner with advanced dose reduction techniques to a single-phase polytrauma WBCT protocol on a 64-slice MDCT scanner. METHODS: Between March and September 2015, 109 polytrauma patients (group A) underwent acute WBCT with a low-dose multi-phase WBCT protocol on a 258-slice MDCT whereas 110 polytrauma patients (group B) underwent single-phase trauma CT on a 64-slice MDCT. The diagnostic accuracy to trauma-related injuries, radiation dose, quantitative and semiquantitative image quality parameters, subjective image quality scorings, and workflow time parameters were compared. RESULTS: In group A, statistically significantly more arterial injuries (p = 0.04) and arterial dissections (p = 0.002) were detected. In group A, the mean (±SD) dose length product value was 1681 ± 183 mGy*cm and markedly lower when compared to group B (p < 0.001). The SDs of the mean Houndsfield unit values of the brain, liver, and abdominal aorta were lower in group A (p < 0.001). Mean signal-to-noise ratios (SNRs) for the brain, liver, and abdominal aorta were significantly higher in group A (p < 0.001). Group A had significantly higher image quality scores for all analyzed anatomical locations (p < 0.02). However, the mean time from patient registration until completion of examination was significantly longer for group A (p < 0.001). CONCLUSIONS: The low-dose multi-phase CT protocol improves diagnostic accuracy and image quality at markedly reduced radiation. However, due to technical complexities and surplus electronic data provided by the newer low-dose technique, examination time increases, which reduces workflow in acute emergency situations.

Recommendations of the ESSR Arthritis Subcommittee on Ultrasonography in Inflammatory Joint Disease.

This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee on the use of ultrasonography (US) in rheumatic disease, focused on the examination of joints in the adult population. The recommended examination technique and protocols used in a radiologic work-up are discussed. The main US features that can lead to a final diagnosis in the most common rheumatic diseases are addressed. The differential diagnosis that should be considered at image interpretation is presented. The role of US in interventional procedures and clinically important recent developments is also discussed.

Early treatment intensification induces favourable radiographic outcomes according to predicted versus observed radiographic progression in early rheumatoid arthritis: a subanalysis of the randomised FIN-RACo and NEO-RACo trials.

OBJECTIVES: Predicted versus observed radiographic progression in early rheumatoid arthritis (POPeRA) was applied to demonstrate how various treatment modalities affect and potentially minimise radiographic progression over time. METHODS: The POPeRA method utilises the baseline radiographic score and patient-reported symptom duration to predict radiographic outcomes. It was applied at baseline, 2, and 5 years to patients with eRA from the randomised Finnish RA Combination trial (FIN-RACo) (n=144) and New Finnish RA Combination Therapy (NEO-RACo) (n=90) trials. For FIN-RACo, patients were randomised either to a single DMARD (sulfasalazine, with or without prednisolone) or to combination therapy (methotrexate+sulfasalazine+hydroxychloroquine, i.e. triple therapy, with prednisolone). In NEO-RACo, all patients were assigned intensified combination therapy (including 7.5 mg prednisolone/day) plus a randomised 6-month induction of either placebo or anti-TNF treatment (infliximab). RESULTS: In FIN-RACo, combination versus monotherapy resulted in superior outcomes in the change from predicted progression over 2 and 5 years (mean 35.7% reduction vs. -32.9%, a worsening from predicted, p=0.001; 34.2% vs. -17.8%, p=0.003, respectively). In NEO-RACo, combination+anti-TNF induction led to significantly greater reductions from predicted progression than combination+placebo, both at 2 and 5 years of follow-up (98.5% vs. 83.4%, p=0.005; 92.4% vs. 82.5%, p=0.027, respectively). Importantly, anti-TNF add-on led to superior reductions from predicted among RF-positive patients (2 years: 97.4% vs. 80.4%, p=0.009; 5 years: 90.2% vs. 80.1%, p=0.030), but not among RF-negative patients. CONCLUSIONS: These results confirm that conventional combination therapy in eRA has a long-term radiographic benefit versus monotherapy. Through POPeRA, it was made evident that anti-TNF induction therapy for 6 months further increases the long-term radiographic benefit of combination therapy in RF-positive patients.

Recommendations of the ESSR Arthritis Subcommittee for the Use of Magnetic Resonance Imaging in Musculoskeletal Rheumatic Diseases.

This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee regarding the standards of the use of MRI in the diagnosis of musculoskeletal rheumatic diseases. The recommendations discuss (1) the role of MRI in current classification criteria of musculoskeletal rheumatic diseases (including early diagnosis of inflammation, disease follow-up, and identification of disease complications); (2) the impact of MRI on the diagnosis of axial and peripheral spondyloarthritis, rheumatoid arthritis, and juvenile spondyloarthritis; (3) MRI protocols for the axial and peripheral joints; (4) MRI interpretation and reporting for axial and peripheral joints; and finally, (5) methods for assessing MR images including quantitative, semiquantitative, and dynamic contrast-enhanced MRI studies.

Anti-type II collagen immune complex-induced granulocyte reactivity is associated with joint erosions in RA patients with anti-collagen antibodies.

INTRODUCTION: Rheumatoid arthritis (RA) patients with autoantibodies against collagen type II (CII) are characterized by acute RA onset with elevated inflammatory measures and early joint erosions as well as increased production of tumor necrosis factor-α (ΤΝF-α) by peripheral blood mononuclear cells (PBMC) stimulated by anti-CII immune complexes (IC) in vitro. Polymorphonuclear granulocytes (PMN) are abundant in RA synovial fluids, where they might interact directly with anti-CII IC in the articular cartilage, but no studies have investigated PMN responses towards anti-CII IC. The aim was to investigate whether PMN react towards anti-CII IC, and to what extent such reactivity might relate to the clinical acute onset RA phenotype associated with elevated levels of anti-CII. METHODS: PMN and PBMC isolated from healthy donors were stimulated with IC made with a set of 72 baseline patient sera (24 anti-CII positive, 48 anti-CII negative) chosen from a clinically well-characterized RA cohort with two-year radiological follow-up with Larsen scoring. PMN expression of cluster of differentiation (CD)11b, CD66b, CD16 and CD32 was measured by flow cytometry, whereas PMN production of myeloperoxidase (MPO) and interleukin (IL)-17, and PBMC production of ΤΝF-α was measured with enzyme linked immunosorbent assay. RESULTS: PMN expression of CD11b, CD66b and MPO, and PBMC production of ΤΝF-α were upregulated whereas PMN expression of CD16 and CD32 were downregulated by anti-CII IC. CD16, CD66b, and MPO production correlated to serum anti-CII levels (Spearman's ρ = 0.315, 0.675 and 0.253, respectively). CD16 was associated with early joint erosions (P = 0.024, 0.034, 0.046 at baseline, one and two years) and CD66b was associated with changes in joint erosions (P = 0.017 and 0.016, at one and two years compared to baseline, respectively). CD66b was associated with baseline C-reactive protein and PBMC production of ΤΝF-α was associated with baseline erythrocyte sedimentation rate, in accordance with our earlier findings. No clinical associations were observed for MPO or IL-17. CONCLUSION: PMN responses against anti-CII IC are more closely associated with early joint erosions than are PBMC cytokine responses. PMN reactivity against anti-CII IC may contribute to joint destruction in newly diagnosed RA patients with high levels of anti-CII.

Sonoelastography: musculoskeletal applications.

All participants for image samplings provided written informed consent. Conventional B-mode ultrasonography (US) has been widely utilized for musculoskeletal problems as a first-line approach because of the advantages of real-time access and the relatively low cost. The biomechanical properties of soft tissues reflect to some degree the pathophysiology of the musculoskeletal disorder. Sonoelastography is an in situ method that can be used to assess the mechanical properties of soft tissue qualitatively and quantitatively through US imaging techniques. Sonoelastography has demonstrated feasibility in the diagnosis of cancers of the breast and liver, and in some preliminary work, in several musculoskeletal disorders. The main types of sonoelastography are compression elastography, shear-wave elastography, and transient elastography. In this article, the current knowledge of sonoelastographic techniques and their use in musculoskeletal imaging will be reviewed.

The role of heat shock proteins in atherosclerosis.

Atherosclerosis is a chronic, multifactorial disease that starts in youth, manifests clinically later in life, and can lead to myocardial infarction, stroke, claudication, and death. Although inflammatory processes have long been known to be involved in atherogenesis, interest in this subject has grown in the past 30-40 years. Animal experiments and human analyses of early atherosclerotic lesions have shown that the first pathogenic event in atherogenesis is the intimal infiltration of T cells at arterial branching points. These T cells recognize heat shock protein (HSP)60, which is expressed together with adhesion molecules by endothelial cells in response to classic risk factors for atherosclerosis. Although these HSP60-reactive T cells initiate atherosclerosis, antibodies to HSP60 accelerate and perpetuate the disease. All healthy humans develop cellular and humoral immunity against microbial HSP60 by infection or vaccination. Given that prokaryotic (bacterial) and eukaryotic (for instance, human) HSP60 display substantial sequence homology, atherosclerosis might be the price we pay for this protective immunity, if risk factors stress the vascular endothelial cells beyond physiological conditions.

Imaging and interpretation of axial spondylarthritis: the radiologist's perspective--consensus of the Arthritis Subcommittee of the ESSR.

This article reflects the radiologist's perspective on the imaging and interpretation of axial spondylarthritis (SpA). The arthritis subcommittee of the European Society of Skeletal Radiology provides a consensus for the following questions: When and how should we image? How should we analyze the images? How should we interpret the imaging findings? To answer these questions, we address the indications in imaging axial SpA and the different imaging techniques, with a special focus on magnetic resonance imaging protocols. The value of different imaging modalities is discussed. For adequate image analysis, knowledge of the anatomy and the pathologic changes in chronic and acute inflammation of the sacroiliac joints and the spine is mandatory. Differential diagnoses of inflammatory lesions of the sacroiliac joints and the spine are addressed due to their importance in image interpretation.

Treatment options of crural pseudoaneurysms.

BACKGROUND: Pseudoaneurysms (PAs) of crural arteries represent rare complications of vascular interventions or surgery. Management of crural PAs includes different treatment options, conservative treatment as well as open surgery or endovascular procedures. We reviewed our experience. PATIENTS AND METHODS: We retrospectively analysed all patients who were diagnosed with crural PAs since 2003. We evaluated etiology, treatment and outcome. Endpoints were target vessel patency, vascular re-intervention and limb loss. RESULTS: A total of 30 patients were diagnosed with crural PAs. PA was caused by vascular intervention in 27 patients (90 %): open balloon thrombectomy (n = 25), subfascial endoscopic perforator vein surgery (n = 1) and transcutaneous catheter-assisted thrombus aspiration (n = 1). In 3 patients (10 %) it was caused by orthopaedic surgical procedures. Location of crural PAs were peroneal artery (n = 11; 36.7 %), posterior tibial artery (n = 10; 33.3 %), anterior tibial artery (n = 5; 16.7 %), and tibioperoneal trunk (n = 4; 13.3 %). Treatment of crural PAs included open surgery (n = 3; 10 %), endovascular procedures (n = 13; 43.3 %) such as endograft implantation (n = 9) or coil embolisation (n = 4), and conservative management (n = 14; 46.7 %). After a median follow-up period of 7 months (range: 0 - 46 months) 8 of 9 endografts were occluded, in none of these patients a minor or a major amputation was necessary. None of the surgically, endovascularly and conservatively treated patients needed a re-intervention for crural PA. A major amputation was necessary in 4 patients due to progression of peripheral arterial disease; none was a directly consequence of the crural PA. CONCLUSIONS: Crural PAs are mainly caused by vascular intervention, most frequently by catheter thrombectomy. As a consequence, we recommend fluoroscopic-assisted balloon thrombectomy over a guide wire as routine technique. In many cases of crural PAs, conservative management is sufficient. The choice of treatment of crural PAs depends on size, location and associated symptoms. Endovascular treatment using endografts is limited by poor long-term patency.

Clinical imaging assessments of knee osteoarthritis in the elderly: a mini-review.

Knee osteoarthritis (OA) in the elderly is one of the most common degenerative age-related joint diseases leading to typical degradation of articular cartilage with severe pain and limitation of joint motion. Its increasing prevalence due to the demographic development of the society has major implications for individual and public healthcare with the increasing necessity for clinical imaging assessment in a high number of individuals. Although conventional X-ray radiographs are widely considered as gold standard for the assessment of knee OA, in clinical and scientific settings they increasingly bare significant limitations in situations when high resolution and detailed assessment of cartilage is demanded. New imaging modalities are broadening the possibilities in knee OA clinical practice and are offering new insights to help for a better understanding of the disease. X-ray analysis in OA of the knee is associated with many technical limitations and increasingly is replaced by high-quality assessment using magnetic resonance imaging or ultrasonography both in clinical routine and scientific situations. These novel imaging modalities enable an in vivo visualization of the quality of the cartilaginous structure and bone as well as all articular and periarticular tissues. Therefore, the limitations of radiographs in knee OA assessment could be overcome by these techniques. This review article should provide an insight into the most important radiological features of knee OA and their systematic visualization with different imaging approaches that can be used in clinical routine.

Transcatheter embolization for the management of acute active inferior epigastric artery hemorrhages.

PURPOSE: To report a retrospective review of all patients who were admitted to the interventional radiology unit at our hospital for transcatheter arterial embolization (TAE) of an acute active hemorrhage of the inferior epigastric artery. METHODS: From 1996 to 2012, 52 consecutive patients (26 men; mean age 63±15 years) with hemodynamically relevant active abdominal wall hematoma were admitted for TAE of the inferior epigastric artery. Of these, 19 patients had spontaneous hemorrhage due to use of anticoagulants, 18 due to abdominal trauma, and 15 due to an iatrogenic complication. All superselective embolizations were performed using a coaxial catheter technique with a 0.018-inch microcatheter introduced through the diagnostic macrocatheter. Various embolization methods, alone or in combination, were applied, including primarily microcoils and polyvinyl alcohol particles. RESULTS: Primary technical success was achieved in 47/52 (90%) patients; the remainder needed a second embolization session (secondary success 100%). The mean puncture-to-hemostasis time was 65.4±35 minutes. No patient developed a large hematoma or pseudoaneurysm at the puncture site. The 30-day mortality was 19% (n=10) and the total cumulative mortality rate was 23% (n=12). Over a mean 67-month follow-up of 39/40 survivors (1 lost to follow-up), no complications from the embolization procedure, such as abdominal wall ischemia, were observed. There were no differences in outcomes based on etiology of the hemorrhage. CONCLUSION: In selected patients with acute active hemorrhage of the IEA in the anterior abdominal wall, TAE is a fast, safe, minimally invasive, and reliable method with a high technical success rate and no long-term complications.

The pattern of acute injuries in patients from alpine skiing accidents has changed during 2000-2011: analysis of clinical and radiological data at a level I trauma center.

OBJECTIVES: During the last decade, many educational efforts and technological improvements have been made to protect skiing athletes from injuries. Whether these efforts have changed the pattern of acute injuries from skiing casualties has not yet been shown on a medical basis, which this longitudinal study examines. METHODS: All patients transferred to the Department of Radiology of our level I trauma center for acute emergency computed tomography (CT) after alpine skiing accidents from 2000 to 2011 were included. We hypothesized that only patients with clinical suspicion for injuries were admitted for acute CT. RESULTS: Of all acute patients after skiing accidents, 2,252 could be included. From 2000 to 2011, all cerebral injuries and vascular arterial injuries statistically significantly decreased (p < 0.05, respectively). However, extremity fractures, facial fractures, and vertebral fractures increased (p < 0.04, respectively). The number of cerebral hemorrhages, thoracic injuries, and abdominal injuries remained unchanged (p = NS). The mean (SD) number of all initial radiological examinations per victim statistically significantly decreased from 2.3 (0.7) in 2000 to 1.5 (0.6) in 2011, whereas the admissions for acute CT have significantly increased (p < 0.02; respectively). CONCLUSIONS: Acute radiological evaluation in skiing accidents has changed during the last decade. The decrease in overall cerebral injuries might be a function of the increasing use of skiing helmets. A protection of the extremities, trunk, spine, and face, however, needs further improvements and their radiological assessment with CT warrants attention in skiing casualties.

Greater trochanteric pain syndrome.

Pain around the greater trochanter is still a common clinical problem that may be secondary to a variety of either intra-articular or periarticular pathologies. Gluteal tendon pathologies are one of the primary causes of greater trochanteric pain, with attrition of the fasciae latae against the gluteus medius and minimus tendons, and the trochanteric bursa being possible causes. Key sonographic findings of gluteal tendinopathy, bursitis, and differential diagnosis are described in this overview. Clinical diagnosis and treatment of greater trochanteric pain syndrome is still challenging; therefore ultrasound is helpful to localize the origin of pain, determine underlying pathology, and, based on these findings, to guide local aspiration and/or injection in cases of tendinopathy and/or bursitis.

Anti-type II collagen antibodies are associated with early radiographic destruction in rheumatoid arthritis.

INTRODUCTION: We have previously reported that high levels of antibodies specific for native human type II collagen (anti-CII) at the time of RA diagnosis were associated with concurrent but not later signs of inflammation. This was associated with CII/anti-CII immune complex (IC)-induced production of pro-inflammatory cytokines in vitro. In contrast, anti-cyclic citrullinated peptide antibodies (anti-CCP) were associated both with late inflammation and late radiological destruction in the same RA cohort. We therefore hypothesized that anti-CII are also associated with early erosions. METHODS: Two-hundred-and-fifty-six patients from an early RA cohort were included. Baseline levels of anti-CII, anti-CCP and anti-mutated citrullinated vimentin were analyzed with ELISA, and rheumatoid factor levels were determined by nephelometry. Radiographs of hands and feet at baseline, after one and after two years were quantified using the 32-joints Larsen erosion score. RESULTS: Levels of anti-CII were bimodally distributed in the RA cohort, with a small (3.1%, 8/256) group of very high outliers with a median level 87 times higher than the median for the healthy control group. Using a cut-off discriminating the outlier group that was associated with anti-CII IC-induced production of proinflammatory cytokines in vitro, baseline anti-CII antibodies were significantly (p = 0.0486) associated with increased radiographic damage at the time of diagnosis. Anti-CII-positive patient had also significantly increased HAQ score (p = 0.0303), CRP (p = 0.0026) and ESR (p = 0.0396) at the time of diagnosis but not during follow-up. The median age among anti-CII-positive subjects was 12 years higher than among the anti-CII-negative patients. CONCLUSION: In contrary to anti-CCP, anti-CII-positive patients with RA have increased joint destruction and HAQ score at baseline. Anti-CII thus characterizes an early inflammatory/destructive phenotype, in contrast to the late appearance of an inflammatory/destructive phenotype in anti-CCP positive RA patients. The anti-CII phenotype might account for part of the elderly acute onset RA phenotype with rather good prognosis.

The time-averaged inflammatory disease activity estimates the progression of erosions in MRI of the sacroiliac joints in ankylosing spondylitis.

A method to estimate the individual ankylosing spondylitis (AS) patient radiological progression of semi-quantitative magnetic resonance imaging (MRI) changes in the sacroiliac joints has not been described yet, which this study examines. Inflammatory disease activity and MRIs of the sacroiliac joints of 38 patients with recent onset established AS were analyzed at baseline and during follow-up. Sacroiliac MRIs were semi-quantitatively assessed using a modification of the "Spondylarthritis Research Consortium of Canada" (SPARCC) method. In each patient, the annual inflammatory disease activity was estimated by the time-averaged C-reactive protein (CRP; mg/l), calculated as the area under the curve. The mean (SD) CRP decreased from 1.3 (1.8) at baseline to 0.5 (0.6) at follow-up MRI (p < 0.04), which has been performed after a mean (SD) disease course of 2.8 (1.5) years. The mean (SD) annual increase (∆) of SPARCC score from baseline to follow-up MRI was 0.4 (0.4). Baseline individual SPARCC sub-score for bone marrow edema did not statistically significantly correlate with individual ∆SPARCC sub-score for erosions (p = N.S.). The individual AS patient correlation between annual time-averaged inflammatory disease activity and each annual ∆SPARCC sub-scores was only statistically significant for erosions (p < 0.01; r = 0.71). Our results show that bone marrow edema and contrast-medium enhancement at baseline do not relate to the progression of erosions but the calculation of the individual patient annual time-averaged inflammatory disease activity allows to estimate the annual progression of erosions in sacroiliac MRIs of patients with AS.