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In 2009, the Assessment of SpondyloArthritis international Society (ASAS) published a definition of ‘active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis’. This new definition of an ‘ASAS-positive MRI’ was integral to new classification criteria for axial spondyloarthritis that were published in the same year. The ASAS MRI definition had the considerable advantage of simplicity and the definition gained popularity as guidance for interpreting MRI of the sacroiliac joints in clinical practice. However, classification criteria are not designed for use in clinical practice with the consequence that overreliance on the presence of bone marrow edema, which is the principal determinant of an ‘ASAS-positive MRI’, may result in a tendency to overcall inflammatory sacroiliitis in the clinical setting. This article aims to inform the reader about the rationale behind the ASAS definition of a positive MRI and ASAS classification criteria, their proper use in research and why they should not be used in clinical practice. The article also contains guidance for an updated imaging protocol and interpretation of images including typical imaging findings, differential diagnosis, and common pitfalls.

To evaluate the frequency of sacroiliitis in older subjects.Consecutive MRI examinations of the sacroiliac joints (SIJs) performed for suspected sacroiliitis (2005-2019) in patients ≥ 18 years were retrospectively evaluated for the presence of active/structural lesions and were categorized for the presence/absence of sacroiliitis. Clinical and imaging parameters were compared between subjects with sacroiliitis according to age groups 40 years, 40-55, and 55 years. Clinical parameters including inflammatory back pain (IBP) and other spondyloarthritis (SpA) features were retrieved from the medical records.A total of 431 patients with SIJs MRI were evaluated: median age, 44 [IQR 35-54]; female:male 267(62%):164(38%). Sacroiliitis was diagnosed in 89 (20.6%) subjects-median age, 41 years [IQR 32-54], 52% females- and was equally prevalent among the different age groups: 40 years old, 23.6%; 40-55, 20%; and 55 years old, 17%, p = 0.43, with active/structural lesions equally dispersed. Older patients ( 55) started suffering from back pain at an older age and had a longer delay in diagnosis. Gender distribution, the presence of IBP, and other SpA features were no different in patients 45 and 55 years of age.The frequency of sacroiliitis on SIJs-MRI in subjects 55 years is similar to its frequency in younger subjects and is associated with the same type and magnitude of active and structural MRI lesions. Clinical parameters such as IBP and additional SpA features are similarly prevalent in older and younger subjects suggesting they suffer from the same disease and differing only in age of presentation.

To compare inter-reader agreement and diagnostic confidence in detecting sacroiliitis by the modified New York criteria (mNY) on digital radiography (DR) versus digital pelvic tomosynthesis assisted DR (DR+DPT), and to evaluate changes in the presence of axial spondyloarthritis (axSpA) according to the Assessment of Spondyloarthritis International Society (ASAS) criteria. One hundred and thirty-eight patients who underwent both DR and DPT with suspicious axSpA in our rheumatologic clinic were included from February 2017 to February 2018. Three radiologists independently graded sacroiliitis and confidence level on DR first and then re-graded them on DPT in a paired manner. Agreement, confidence, and diagnostic accuracy were evaluated for readers. Changes in the presence of disease by mNY and ASAS criteria were assessed between DR alone and DR+DPT. On DR alone, 73 patients were assessed with radiographic sacroiliitis, and 85 were classified into axSpA by the ASAS criteria; however, 78 and 85, respectively, were classified on DR+DPT. With the assistance of DPT, 17 and 12 patients changed to the disease positivity according to the mNY and ASAS criteria, respectively; the negative results changed to positive in 11 and six patients, respectively. For all readers, agreement improved with DPT (0.79 to 0.89). DR+DPT achieved higher diagnostic accuracy (AUC, P < 0.05). The combination of DR and DPT achieved a higher diagnostic performance than that of DR alone, with better agreement. On DR+DPT, the diagnoses of 9.0% of patients with suspicious axSpA (12 of 134) were changed to the status of disease by the ASAS criteria.

The purpose of our study was to determine the cost-effectiveness of radiography and MRI-based imaging strategies for the initial diagnosis of sacroiliitis in a hypothetical population with suspected axial spondyloarthritis. A decision analytic model from the health care system perspective for patients with inflammatory back pain suggestive of axial spondyloarthritis was used to evaluate the incremental cost-effectiveness of 3 imaging strategies for the sacroiliac joints over a 3-year horizon: radiography, MRI, and radiography followed by MRI. Comprehensive literature search and expert opinion provided input data on cost, probability, and utility estimates. The primary effectiveness outcome was quality-adjusted life-years (QALYs), with a willingness-to-pay threshold set to $100,000/QALY gained (2018 American dollars). Radiography was the least costly strategy ($46,220). Radiography followed by MRI was the most effective strategy over a 3-year course (2.64 QALYs). Radiography was the most cost-effective strategy. MRI-based and radiography followed by MRI-based strategies were not found to be cost-effective imaging options for this patient population. Radiography remained the most cost-effective strategy over all willingness-to-pay thresholds up to $100,000. Radiography is the most cost-effective imaging strategy for the initial diagnosis of sacroiliitis in patients with inflammatory back pain suspicious for axial spondyloarthritis.

The sacroiliac joint (SIJ) is an amphiarthrosis composed of a posterior syndesmosis and an anterior cartilaginous portion, with limited yet present mobility. Its main function is to transmit the load from the axial skeleton to the lower limbs and vice-versa; it is susceptible to early mechanical and degenerative changes which are much more common than inflammatory sacroiliitis. Magnetic resonance imaging (MRI) has increasingly been used to evaluate these changes, and while subchondral bone marrow edema (BME) is a common finding related to both, care must be taken when applying the ASAS research MRI definition for sacroiliitis without considering lesion BME topography, size and depth, concomitant structural damage and, of course, the clinical picture. In this review, we will discuss the anatomy and biomechanics of the SIJ, the noninflammatory causes of SIJ subchondral BME, and how these concepts combined can be used to increase our diagnostic confidence.

To determine the prevalence of sacroiliitis among patients who have been referred for MR arthrography. A retrospective search identified 130 consecutive MR arthrograms of the hip performed on a 1.5T Siemens Avanto at our institution from August 2013 to August 2014. Four studies were excluded due to the absence of a coronal short tau inversion recovery sequence of the pelvis, leaving 126 studies for analysis. A musculoskeletal radiology fellow and three attending musculoskeletal radiologists reviewed the images for the presence of bone marrow edema affecting the sacroiliac joints. Only cases of bone marrow edema meeting the Assessment of SpondyloArthritis international Society definition were considered positive. The two-tailed Fisher’s exact test was used to compare the prevalence of positive MRI findings among age and gender groups. GraphPad InStat (GraphPad Software) was used for statistical calculations. Patients less than 40 years of age demonstrated a statistically higher prevalence of positive MRI findings of sacroiliitis when compared to patients older than 40 (p = 0.0082). No difference in prevalence was found between genders. Overall prevalence of MRI signal alteration suggestive of sacroiliitis as defined by the Assessment of SpondyloArthritis international Society was 4.8%. Among the six patients with positive findings, two were subsequently diagnosed with spondyloarthritis. Hip pain may be a presenting symptom of spondyloarthritis and attention should be paid to the sacroiliac joints during screening examinations, particularly in patients less than 40 years of age.

To investigate the diagnostic values of T2 mapping and diffusion-weighted imaging (DWI) for active sacroiliitis in ankylosing spondylitis (AS) and to evaluate the correlations of T2 and ADC values with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Spondyloarthritis Research Consortium of Canada (SPARCC) scores. A total of 77 AS patients with sacroiliitis and 45 healthy controls were enrolled. All patients were scanned by standard magnetic resonance imaging longitudinal relaxation time (T1)-weighted imaging (T1WI), fat-saturated T2-weighted imaging (FS-T2WI)] and DWI, and T2 mapping of the sacroiliac joints. According to whether subchondral bone marrow edema was present in the FS-T2WI sequence, the 77 patients were divided into an active group (41 cases) and an inactive group (36 cases). The T2 and apparent diffusion coefficient (ADC) values of the subchondral bone marrow were measured in the active group, the inactive group, and the healthy control group. The average T2 and ADC values were compared among the three groups. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic efficacy of T2 and ADC values for sacroiliitis. The correlations of T2 and ADC values with the BASDAI score and the SPARCC score were analyzed. The T2 and ADC values in the active group were higher than those in the inactive group, while that in the inactive group were significantly higher than those in the healthy control group (p

To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME). A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16–45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated. BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis. Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is ‘positive’ or ‘not positive’ for sacroiliitis associated with spondyloarthritis.

Polymyalgia rheumatica (PMR) is almost an exclusive disease of adults over the age of 50, and only a few cases have been reported. Two 46-year-old females visited our locomotor pain clinic with multiple joint pain with increased acute phase reactants. Rheumatologic markers, and HLA-B27 were checked. Serum protein electrophoresis and serum immunofixation electrophoresis, imaging studies including plane image, sonography, and magnetic resonance image was done. 18F-Fludeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) showed characteristic findings of PMR, without evidences of sacroiliitis. Since PMR can develop in mid 40s, a high index of suspicion is necessary in younger patients presenting the bilateral pain in shoulders, hips, and back, with elevated acute phase reactants. Furthermore, in addition to the previous case reports, FDG-PET/CT is helpful in making early differential diagnosis of PMR in patients under the age of 50. Here we present two cases of PMR onset in the mid-40s emphasizing the importance of diagnostic imaging for early differential diagnosis in PMR.

In the past two decades, MRI has gained a major role in research and clinical management of patients with inflammatory arthritides, particularly in spondyloarthritis (SpA), rheumatoid arthritis (RA), and osteoarthritis (OA). MRI is regarded as the most sensitive imaging modality for detecting early SpA in young patients with inflammatory back pain and normal radiographs of the sacroiliac joints. The recently published Assessment of SpondyloArthritis International Society classification criteria for axial SpA include for the first time a positive MRI demonstrating sacroiliitis as an imaging criterion indicative of SpA together with at least one clinical feature of SpA. Recent data show that systematic assessment of sacroiliitis displayed on MRI has much greater diagnostic utility than previously reported and highlight the diagnostic relevance of structural lesions. In RA, MRI has predictive value for the development of disease in new onset undifferentiated arthritis, and MR pathology at disease onset is a highly significant predictor of radiographic erosions. Consequently MRI has been credited with an important role in the new ACR/EULAR 2010 classification criteria for RA. In OA, bone marrow edema (BME) and synovitis may serve as biomarkers in interventional trials. Treatment interventions targeting BME and synovitis observed on MRI in inflammatory arthritides may have a disease-modifying effect as these lesions are potentially reversible and have been shown to be associated with structural progression. Research should focus on the prognostic significance of MRI lesions in larger cohorts and whether adding MRI to routine care improves clinical and radiographic outcome in patients with inflammatory arthritides.

The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA). A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded. STIR and T1/Gd sequences had 100 % agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5 %) patients, 15 (83 %) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33 %, SP = 85 %) and T1/Gd synovial enhancement (SN = 36 %, SP = 92 %). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55 %, SP = 87 %, LR + =4 .2; T1/Gd: SN = 55 %, SP = 92 %, LR + = 6.9). MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis.

Answer: Septic sacroiliitis with sequestration Septic sacroiliitis is an uncommon entity, accounting for less than 1 % of cases of adult septic arthritis [1]. Infection of the sacroiliac joint typically occurs by hematogenous spread of bacteria and less commonly by direct extension from adjacent soft tissue or bone [2]. Intravenous (IV) drug use is a predisposing risk factor for septic arthritis, particularly of the sacroiliac joint. Staphylococcus aureus is the most common pathogen isolated [1]. CT-guided aspiration of the joint is indicated when blood cultures are negative, which occurs in approximately 75 % of reported cases [2]. Treatment depends on the severity of the infection; however, long-term antibiotics are the mainstay. Abscesses usually require drainage. A more extensive procedure is necessary if an osseous sequestrum is present [3]. A sequestrum represents a focus of necrotic bone secondary to devascularization and resorption of the surrounding bone, as seen in this case (Figs. 3 and 4, Test Yourself: Question). The sequestrum serves as a nidus of infection as it is avascular and is not penetrated by antibiotics. On magnetic resonance (MR) imaging, sequestra appear as low signal intraarticular fragments on all sequences and do not enhance [1]. Additional MR findings of septic sacroiliitis include erosions, abnormal cartilage signal intensity on T1-weighted images, and areas of increased intensity within the joint on T2-weighted images. A highly specific finding is demonstration of bone marrow edema and inflammatory muscle tissue on STIR and T2weighed images [1, 4–6]. Computed tomography (CT) findings include widening of the joint space, erosions, thinning of the periarticular fatty tissue layer, sequestra, and abscess formation [1, 7]. Our patient had a history of IV drug use and had been receiving a course of IV antibiotics for methicillinsensitive Staphylococcus aureus bacteremia and multifocal subcutaneous abscesses. The abscesses improved; however, she complained of persistent fevers, drenching night sweats, low back pain, and difficulty ambulating on her right leg. Initial MR images demonstrate patchy bone marrow edema centered along the sacroiliac joints bilaterally, the right greater than left. Focal curvilinear structures within the right sacroiliac joint are low in signal on all sequences and suspicious for osseous sequestra. A followup nonenhanced pelvic CT demonstrates erosive changes and widening of the right sacroiliac joint. Areas of sclerotic bone in the posterior-inferior portions of the right sacroiliac joint correspond to low signal foci on the MR and are consistent with sequestrum formation. This case demonstrates the importance of recognizing an osseous sequestrum on MR imaging, which is a sign of advanced disease. In our anecdotal experience, postcontrast imaging best demonstrates the osseous sequestra, which appear as low signal, nonenhancing, intraarticular fragments. The patient’s sacroiliac joint infection was refractory to IV antibiotic therapy given the presence of sequestra, which necessitates more aggressive treatment in the form of sequestrectomy. The patient was scheduled for treatment, but subsequently was lost to follow-up. The case presentation can be found at doi: 10.1007/s00256-015-2310-6.

The purpose of the present study was to evaluate the role of diagnostic tools and management options for patients with pyogenic sacroiliitis, including potential complications. This retrospective study included 16 patients with pyogenic sacroiliitis who were admitted to a single orthopaedic centre between 2007 and 2012. The following data were collected: demographics, history, radiography, magnetic resonance images (MRI), biological data, type of pathogenic agent, abscess formation, type of management, and clinical outcome. Our study demonstrated that only one-fifth of the patients with lumbogluteal or hip pain had established diagnoses of suspected pyogenic sacroiliitis upon admission. MRIs confirmed this diagnosis in all cases. MRI examinations revealed joint fluid in the sacroiliac joint and significant oedema of the adjacent bone and soft tissues. In 12 of the 16 cases, erosions of the subchondral bone were encountered. Contrast-enhanced MRI revealed that 9 patients had abscesses. All patients received antibiotic therapy. Antibiotic treatment was only successful in 9 cases. The other 7 patients underwent computed tomography (CT)-guided abscess drainage. Drainage was sufficient for 4 patients, but 3 patients required open surgery. One patient required sacroiliac arthrodesis. The clinical outcomes included minimal disability (n = 10), moderate disability (n = 5), and full disability (n = 1) of the spine. Contrast-enhanced MRI is mandatory for a reliable diagnosis. Abscess formation was observed in approximately half of the MRI-diagnosed sacroiliitis cases and required minimally invasive drainage under CT guidance or frequently open surgery.

Objective. To investigate the diagnostic value of magnetic resonance (MR) imaging in detecting septic sacroiliitis and to determine whether the MR characteristics allow this entity to be differentiated from sacroiliitis in spondylarthropathy (SpA). Patients and design. The imaging findings of 11 patients with septic sacroiliitis were retrospectively analyzed by two experienced radiologists. Radiographic surveys of the pelvis as well as computed tomography (CT) and MR images of the sacroiliac joints were available in all cases. Seven of the patients additionally underwent a follow-up MR examination. The MR imaging protocol comprised combinations of coronal and transverse T1-weighted spin-echo (SE) or fast SE sequences, T2-weighted gradient-echo (GE) sequences and short tau inversion recovery sequence (STIR) sequences as well as dynamic contrast- enhanced T1-weighted acquisitions. Results. Three patients with a short disease history showed anterior and/or posterior subperiosteal infiltrations (”lava cleft phenomenon”), transcapsular infiltrations of juxta-articular muscle layers, which obscured the fasciae, and periarticular bone marrow edema. The eight patients with more advanced stages of sacroiliitis additionally showed abscess formation, sequestration, and erosion. At follow-up MR examination (n=7) under systemic antibiotic treatment, the morphologic characteristics showed progression (n=1), regression (n=4), unchanged findings (n=1), or a mixed response (n=1). Clinical improvement precedes resolution of the MR findings. Conclusions. Anterior and/or posterior subperiosteal infiltrations and transcapsular infiltrations of juxta-articular muscle layers were depicted in all patients. These MR imaging findings are characteristic of septic sacroiliitis and may be used to differentiate this entity from sacroiliitis in SpA.

Objective. To determine the prevalence of radiographic evidence of sacroiliitis in a large population of patients with psoriatic arthritis. Patients and design. Patients were recruited from 15 clinical centers. This was part of a large, multicenter study of patients with an established diagnosis of ankylosing spondylitis, psoriatic arthritis, or reactive arthritis. For this cohort, an established diagnosis of psoriatic arthritis was required, with cutaneous manifestations and involvement of at least three appendicular joints. At entry, patients were not selected for the presence of axial involvement. Radiographs – one anteroposterior view of the pelvis and one oblique view of each sacroiliac joint – were graded using the New York classification scale by a musculoskeletal radiologist masked to the specific diagnosis and clinical symptoms. Re-evaluation of 10% of the films 3 years later quantified intraobserver variability. Results. Two hundred and two patients with psoriatic arthritis were studied. Duration of the disease averaged 12 years; all patients had psoriasis and peripheral arthritis. The prevalence of radiographic evidence of sacroiliitis (grade 2 or higher) was 78%; 71% of these had grade 3 disease. Conclusions. Previously reported prevalence of sacroiliitis in patients with psoriatic arthritis ranges from 30% to 50%. The prevalence of radiographic evidence of sacroiliitis in this large multicenter cohort of patients with appendicular psoriatic arthritis was substantially higher.

Objective. To determine in a prospective study the normal MRI morphology of the sacroiliac joints (SIJs) in relation to age and sex during adolescence. Design and patients. A total of 98 children (63 boys, mean age 12.7±2.8 years; 35 girls, mean age 13.7±2.3 years), ranging in age from 8 to 17 years, with juvenile chronic arthritis (JCA) but without signs of sacroiliitis fulfilled the study prerequisites (no back pain and no pathologic changes of the SIJs on physical examination before MRI in a 1.5-year follow-up). An additional eight HLA-B27-negative boys and eight HLA-B27-negative girls without arthritis served as controls. The MRI protocol comprised a T1-weighted SE sequence, an opposed-phase T2*-weighted GE sequence, and a dynamic contrast-enhanced study in single-section technique. Results. Noncontrast MRI permitted differentiation of “open” from ossified segmental and lateral apophyses of the sacral wings, with a significant difference in age (P

Spondyloarthropathies including ankylosing spondylitis (AS) require early diagnosis to prevent irreversible changes. Sacroiliitis is a common initial manifestation of AS and is frequently diagnosed by magnetic resonance imaging (MRI). The goal of our study was to assess color Doppler ultrasonography as a potential diagnostic tool in suspected sacroiliitis in comparison with MRI representing the gold standard.Fifty-one consecutive patients with AS and sacroiliitis and 30 control subjects underwent contrast-enhanced MRI and high resolution color Doppler and duplex ultrasonography of both sacroiliac joints (SIJ) for the detection of vascularization and blood flow spectral Doppler waveform analysis.MRI demonstrated active disease in 27 and inactive disease in 24 patients. CDUS detected pulsatile monophasic wave spectral waveform flow in 22 patients with the active disease, and triphasic in 7 patients with inactive disease and in 8 control patients. The sensitivity, specificity, positive predictive value and negative predictive value for active sacroiliitis detection with CDUS were 82 % (95 % CI, 68-91 %), 92 % (95 % CI, 85-96 %), 91 % (95 % CI, 84-96 %), and 84 % (95 % CI, 70-92 %), respectively, for pulsatile monophasic wave spectral waveform Doppler sonography. MRI of SIJ was negative in all 30 (60 SIJ) control participants.Our results show that CDUS is a practical and useful tool in the diagnosis of active sacroiliitis.

The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrast enhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrast enhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrast enhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, paEuro dagger < aEuro dagger 0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis.

The diagnosis of juvenile spondyloarthritis (JSA) is rarely entertained in young children who present with back and leg pain. We present a case of a 6-year-old male who presented with a 3-year history of severe back and leg pain and a positive Gower's sign, and was given a presumed diagnosis of muscular dystrophy. Presenting serologic evaluation included a mildly elevated sedimentation rate and C-reactive protein (CRP). Computed tomography of the pelvis demonstrated large erosions affecting both sacro-iliac joints. Despite the unusually young age of this patient, ankylosing spondylitis seemed the most plausible diagnosis. Following rheumatological evaluation and treatment for JSA, he showed significant clinical improvement. His disease, however, has not entirely remitted with signs of enthesitis at the Achilles tendon and knees. We present this case to illustrate that JSA could account for symptoms at an early age and not considering it could lead to multiple medical visits and diagnoses. To our knowledge, based on a search of the World literature, this would appear to be the youngest case of JSA reported with demonstrable severe sacroiliitis.

Pseudoarthrosis and ankylosis of the vertebral spine associated with Takayasu's arteritis is extremely rare. We present a patient with the entity who was HLA-B27 negative and had normal sacroiliac joints. The association between Takayasu's arteritis and ankylosing spondylitis appears real but seemingly rare.

Purpose. To verify the diagnostic value of contrast-enhanced MR imaging compared with conventional radiography in the diagnosis of sacroiliitis in children. Design and patients. Radiography and MR imaging of the sacroiliac joints were performed in 185 children subdivided into the following groups according to the modified European Spondyloarthropathy (SpA) Study Group (ESSG) criteria: group 1, undifferentiated spondyloarthropathy (uSpA) (n=53, 94.5% HLA-B27+); group 2, differentiated SpA (n=45, 93.3% HLA-B27+); group 3, patients with no signs of SpA other than oligoarthritis (n=39, 92.3% HLA-B27+); group 4, HLA-B27+ controls with various other non-SpA diagnoses (n=22); and group 5, HLA-B27– controls with various other non-SpA diagnoses (n=26). Radiographs were evaluated on the basis of the modified New York criteria independently by three experienced radiologists masked to the clinical data. In a second step, the same radiologists independently evaluated the MR images without knowledge of the clinical data and radiographic findings using the recently published criteria developed by our group. These criteria allow differentiation of acute and chronic inflammatory changes. Results. Radiography demonstrated sacroiliitis in 18 patients: 4 of 53 in group 1 (7.5%), 14 of 45 in group 2 (31%), but none in groups 3, 4 and 5. In contrast, MR imaging demonstrated acute and/or chronic sacroiliitis in 44 patients: 18 of 53 in group 1 (34%), 21 of 45 in group 2 (46.7%) and 5 of 39 in group 3 (12.8%), but none in groups 4 and 5. The percentage of sacroiliitis detected by MR imaging was significantly higher than that detected by radiography (P

Objective. To compare magnetic resonance (MR) imaging, computed tomography (CT), and radiography in the detection of sacroiliitis accompanying ankylosing spondylitis (AS). Design and subjects. Nine volunteers and 24 patients were recruited. Radiography, CT, and MR imaging were completed within a 1-week period in 24 patients with AS. In precontrast MR examination, spin-echo T1, fast spin-echo T2, and gradient echo with rephasing T2* images were obtained without fat saturation using a 0.3-T imager for all volunteers and patients. Postcontrast MR examination was performed using the same precontrast SE T1 sequence for patients with AS. Results and conclusions. MR imaging directly showed the normal cartilage in all 16 sacroiliac joints of the 8 volunteers. In the 24 patients with AS, cartilage abnormalities were observed in 42 sacroiliac joints. More diagnoses of sacroiliitis were made using MR and CT imaging than using radiography (P

Objective. To make a detailed evaluation of the clinical and radiological course of five children with chronic recurrent multifocal osteomyelitis (CRMO). Emphasis was laid on the correlation between clinical data and radiological findings. Design and patients. Clinical data, histology (n=11), bone scintigraphy (n=17), and the plain radiographs (n=198) of these patients were reviewed. The mean time of observation was 6.6 years (range 1–14.5 years). Thirty-two lesions seen at the time of primary diagnosis (n=22) or during the course of the disease (n=10) were evaluated. Twenty-seven foci were located in bone; in five cases the sacroiliac joints were involved. Results. Bone scintigrams showed nearly all foci (31/32) and were especially helpful in clinically asymptomatic lesions (14/32) or foci which were radiographically difficult to detect or not seen at all (8/32). Only 14 of 32 foci were locally symptomatic clinically. In all cases with a short interval (≤3 weeks) between the onset of local symptoms and evaluation by plain radiographs (n=5) osteolysis was shown without a sclerotic margin. All bone lesions with a longer duration of local symptoms (n=7) revealed a variable radiographic pattern: osteolysis with sclerotic rim in three, a mixed lytic-sclerotic lesion in three and pure sclerosis in one. In two cases low back pain could be ascribed to sacroiliitis. Conclusion. Only careful correlation between clinical, scintigraphy and radiographic features permits an accurate assessment of disease activity in CRMO. The bone lesions detected radiographically soon after the onset of symptoms resemble those of acute osteomyelitis.

Radiographs were reviewed in a group of nine patients with classical seropositive rheumatoid arthritis who on tissue typing were found to express the class I HLA-B27 allele. Radiographs were analyzed with regard to whether or not they demonstrated radiographic features of (1) classical rheumatoid arthritis, (2) seronegative arthritis, or (3) mixed features of rheumatoid and seronegative arthritis. Five patients (55%) displayed radiographic features consistent with a diagnosis of rheumatoid arthritis, two patients (22%) showed radiographic features of seronegative disorder (periostitis and sacroiliitis), and two patients (22%) showed a mixed picture with evidence of both rheumatoid arthritis and a seronegative disorder. Thus, the HLA-B27 allele contributed to the radiographic features in 44% of patients with rheumatoid arthritis and associated HLA-B27. Thus, the wide range of findings in our population indicates that the radiographic attributes are not specific enough to constitute a unique subpopulation of patients with rheumatoid arthritits.

Computed tomography (CT) was used in a prospective study of the sacroiliac joints in 86 patients with Crohn disease to determine the type and frequency of sacroiliac joint abnormalities present in this population. The CT findings were correlated with review of the clinical history in 64 patients. Computed tomography demonstrated changes of sacroiliitis in 29% of the study group. This high prevalence of sacroiliac joint abnormality was found even in those under 30 years of age. It exceeds the 11–19% previously reported from plain film examination, reflecting the greater sensitivity of CT. In the subgroup of 64 patients studied clinically, 19 (30%) had abnormal sacroiliac joints on CT, but only 2 (3%) reported symptoms related to the sacroiliac joints.

The prevalence of radiological abnormalities of the sacroiliac joints, the manubriosternal joint, and the lumbar spine were assessed, and quantitative sacroiliac scintigraphy was performed in 151 patients with a history of chronic inflammatory back pain and in 31 controls with non-inflammatory back pain. Sacroiliitis was found in 124 patients (82%), manubriosternal lesions in 84 patients (56%), and lesions of the lumbar spine in 58 patients (38%). In 19 patients (13%), manubriosternal lesions provided the sole radiological abnormality and in five patients (3%) no radiological abnormality could be demonstrated at any of these sites. Quantitative sacroiliac scintigraphy showed increased values in 69 of 137 patients examined (50%), but also in 10 out of 12 control patients with disc degeneration (83%) and is, therefore, nonspecific for inflammatory lesions. Radiological examination of the manubriosternal joint is recommended in patients with inflammatory back pain without radiographic evidence of sacroiliitis.

Juxta-articular inflammatory masses, sternomanubrial or sternoclavicular, were noted in two women who were subsequently found to have ankylosing spondylitis. The differential diagnosis of juxta-articular masses should include systemic rheumatic disorders as well as tumor or infection.