Seronegative spondyloarthropathies: what radiologists should know

Clinical and imaging features of six Han patients with SAPHO syndrome

BACKGROUND

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare autoimmune disease characterized by skin or osteoarticular damage. SAPHO syndrome is often misdiagnosed or missed diagnosis due to lack of overall understanding of the disease by clinicians.

PURPOSE

To analyze the clinical symptoms and imaging features of six Han patients with SAPHO syndrome in order to provide reference for doctors to diagnose SAPHO syndrome.

MATERIAL AND METHODS

This study retrospectively analyzed the clinical data of six Han patients with SAPHO syndrome.

RESULTS

All six Han patients with SAPHO syndrome had severe acne or pustulosis of the hands and feet, and all of them had osteoarticular damage, including five cases involving the sternoclavicular joint. Some patients showed a specific and typical "bull's head" sign on 99mTc-labeled methylene diphosphonate bone imaging. Among the six patients recruited, there was one thoracic vertebra, one cervical vertebra, one sacroiliac joint, and one peripheral joint involvement. Two patients had limited activity due to severe osteoarticular damage.

CONCLUSION

Due to the atypical clinical symptoms of SAPHO syndrome, most patients will experience a tortuous and long diagnostic process, while a correct understanding and timely intervention of SAPHO syndrome are essential to improve the prognosis of patients.

Successful Treatment of SAPHO Syndrome Complicated with Ankylosing Spondylitis by Secukinumab: A Case Report

Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is characterized by a wide range of dermatological and musculoskeletal manifestations, and its outcome has recently been improved greatly by optimizing management. However, the treatment strategies are not standardized and require further refinement. Secukinumab, a fully human monoclonal antibody targeting IL-17A, is approved for the treatment of autoimmune psoriasis, psoriatic arthritis (PsA), and ankylosing spondylitis (AS). Here, a 53-year-old man was diagnosed with AS, and he presented scattered pustulosis in both hands and feet with a 5-year history of recurrent lumbosacral area pain and abnormal pain in the neck and front chest area. Secukinumab improved the patient’s cutaneous lesion and prevented musculoskeletal pain by substituting adalimumab. Although only a few cases have been reported that secukinumab can effectively treat SAPHO syndrome complicated with AS, the efficacy remains controversial. Therefore, we hope to provide a novel valuable therapeutic strategy for SAPHO syndrome management, particularly in patients with skin lesions.

Prevalence and characteristics of diffuse idiopathic skeletal hyperostosis (DISH) in Italy

Purpose

Diffuse idiopathic skeletal hyperostosis (DISH) is a benign condition characterized by ossification of the spine and prominent enthesopathies. Highly heterogeneous epidemiological figures have been reported in the literature, while in Italy the largest study has been conducted in 1992. The aim of our research is to contribute updated information about prevalence of DISH in Italy and to describe the clinical and radiographic characteristics associated with the disorder.

Material and methods

A retrospective review of lumbosacral spine, thoracic spine and pelvis radiographs was performed. Consecutive patients visiting the emergency department of our Institution over 3 years were enrolled. Presence of DISH was evaluated applying the Resnick and Niwayama criteria. Clinical and radiological features were also assessed.

Results

We included 1012 individuals (60.6% women), and DISH was present in 130 cases. The overall prevalence of DISH was 12.8% (95% CI 10.8–15.1), with higher figures in the male sample (16.8%) than in females (10.3%). In binary logistic regression adjusted for age, BMI (OR 1.50, p < 0.001) diabetes (OR 1.85, p = 0.003), hypertension (OR 2.04, p = 0.007) ischiopubic enthesopathy (OR 7.08, p < 0.001), iliac crest enthesopathy (OR 4.63, p < 0.001) and greater trochanter enthesopathy (OR 3.51, p < 0.001), were significantly associated with the condition.

Conclusion

The prevalence of DISH observed in our study is consistent with previous literature, and we confirm that the disorder is more frequently retrieved in men and that it is associated with the presence of metabolic disorders and pelvic enthesopathy. Knowledge about the epidemiology and characteristics of DISH is needed to properly identify the condition.

A Systematic Approach to Diagnosing Arthritis Based on Radiological Imaging

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Radiology plays key roles in diagnosis of arthritis. We herein suggest an algorithmic approach to diagnosing arthritis. First, the number of joint involvements is reviewed. Monoarticular arthritis includes septic arthritis, pigmented villonodular synovitis, and synovial chondromatosis. Second, polyarticular arthritis can be categorized by its characteristics: erosive, productive and mixed. Erosive disease includes rheumatoid arthritis, hemophilia, and amyloidosis while productive disease includes osteoarthritis, and hemochromatosis. Third, mixed diseases are subcategorized by symmetricity. Ankylosing spondylitis and inflammatory bowel disease related arthritis affect joints symmetrically while psoriatic arthritis, reactive arthritis, and crystalline arthropathy are asymmetric. Adjacent soft tissue density, periostitis, and bone density are ancillary findings that can be used as additional differential diagnostic clues. The final step in identifying the type of arthritis is to check whether the location is a site frequently affected by one particular disease over another. This systematic approach would be helpful for radiologist to diagnose arthritis.

Nail and enthesis assessment in patients with psoriatic disease by high frequency ultrasonography: findings from a single-centre cross-sectional study

PURPOSE

To characterize nail and enthesis abnormalities using high frequency ultrasound (HFUS) in patients with psoriasis (PSO), psoriatic arthritis (PSA) with PSO, and PSA sine PSO.

MATERIAL AND METHODS

Patients with PSO, PSA with PSO, and PSA sine PSO were evaluated and compared in a cross-sectional single centre study. Nail and enthesis abnormalities were evaluated by HFUS using high frequency probes (27 MHz). After a descriptive assessment, Brown University Nail Enthesis Scale (BUNES) and Madrid Sonography Enthesitis Index (MASEI) were used to assess nail and enthesis, respectively.

RESULTS

Fifty-nine patients were enrolled (19 PSO, 22 PSA with PSO, 18 PSA sine PSO). In patients with PSO and in those with PSA and PSO, HFUS evaluation identified the following nail alterations characterised by thickened matrix, inhomogeneous echogenicity of the nail bed, and increased blood flow by power Doppler. In 38.9% patients with PSA sine PSO, a subclinical nail involvement was described. No difference was observed comparing BUNES values in three groups. In PSA patients with PSO and in those with PSA sine PSO, HFUS assessment of entheses mainly showed a hypoechoic aspect and thickness of the tendon, focal cortical erosion, and ossification. A subclinical enthesis involvement in 47.4% patients with PSO was observed. No difference was reported comparing MASEI values in three groups.

CONCLUSION

Qualitative and quantitative abnormalities of nail and enthesis were demonstrated by HFUS in patients with PSO, PSA with PSO, and PSA sine PSO, suggesting a practical additional tool to be used in clinical settings. Furthermore, HFUS highlighted a subclinical nail involvement in patients with PSA sine PSO and enthesis subclinical alterations in patients with PSO.

Female with Ankylosing Spondylitis from the 7th–6th century BCE Lori Berd burial (Armenia)

A female skeleton from the Lori Berd archaeological cemetery, located near the city of Stepanavan (Lori Province of Armenia) is described. Palaeopathological analysis revealed a variety pathology (ankylosis of the sacroiliac joints, ankylosis of the vertebrae, syndesmophytes, ankylosed of the costovertebral and costotransverse joint fusions, kyphosis, lordosis, fracture of the anterior inferior iliac spine and traumatic lesions). This paper reports a new case of ankylosing spondylitis in a skeleton and a differential diagnosis performed to determine the etiology of the condition. The vertebral bodies remodel and together with the associated syndesmophytes form a continuous, smooth bone surface that is sometimes referred to as “bamboo spine”. In this skeleton changes in the spine, ribs, the sacrum, acetabulum, head of the femur and greater trochanter, as well as the anterior inferior iliac spine are typical of ankylosing spondylitis in advanced stage. Addtionally, there were signs of a traumatic death with injuries sustained to the scapula and vertebra. Using osteological markers in combination with the reconstruction of the archaeological context, the burial pattern suggests that the pathology the female suffered was likely due to her physical deficiencies.

Fluorodeoxyglucose PET/CT of Arthritis in Rheumatic Diseases: A Pictorial Review

Rheumatic diseases are various painful conditions that affect joints, bones, cartilage, tendons, ligaments, and muscles. Arthritis is a typical condition of rheumatic disease. Although rheumatoid arthritis is a representative rheumatic disease, various diseases other than rheumatoid arthritis can also affect joints, and differential diagnosis of rheumatic diseases is often difficult owing to the similar clinical manifestations. However, accurate diagnosis is crucial for an appropriate treatment strategy. The utility of fluorine 18 fluorodeoxyglucose (FDG) PET/CT has been established, and it is widely used for assessing malignancies. In addition to accumulating in tumor cells, FDG also accumulates in inflammatory tissue, allowing FDG PET/CT to demonstrate arthritis. PET/CT allows evaluation of whole-body articular and extra-articular lesions in one examination, representing a key advantage over US and MRI, which allow assessment of only a few regions because of their limited field of view. Although FDG PET/CT is sensitive for detecting inflammatory lesions, the uptake itself is nonspecific; therefore, knowledge of characteristic uptake patterns is necessary to narrow the differential diagnosis in rheumatic disease. Furthermore, pathognomonic extra-articular findings such as vasculitis, skin lesions, lymphadenopathy, and chondritis play an important role in achieving accurate diagnosis. The authors present the FDG PET/CT appearances of (a) rheumatoid arthritis and allied disorders (polymyalgia rheumatica, remitting seronegative symmetrical synovitis with pitting edema, adult-onset Still disease), (b) spondyloarthritis (ankylosing spondylitis, psoriatic arthritis, reactive arthritis, inflammatory bowel disease arthritis, SAPHO [synovitis, acne, pustulosis, hyperostosis, and osteitis] syndrome, chronic recurrent multifocal osteomyelitis), and (c) miscellaneous systemic disorders with arthropathy (relapsing polychondritis, multicentric reticulohistiocytosis, amyloidosis, sarcoidosis, hemophilia). ^©RSNA, 2020.

Comparative analysis and differentiation between SAPHO syndrome and spondyloarthropathies using whole-spine MRI

AIM

To determine the imaging characteristics of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome and seronegative spondyloarthropathies (SpAs) on whole-spine magnetic resonance imaging (WS-MRI) and evaluate the role of WS-MRI in the diagnosis and differentiation of the two diseases.

MATERIALS AND METHODS

Twenty-eight patients with SAPHO and 44 with SpAs were included. All patients were symptomatic and clinically diagnosed with SAPHO or SpAs, and all underwent WS-MRI for comparison of imaging characteristics.

RESULTS

The mean age of the SAPHO patients was 48.7 ± 12.7 years, while that of the SpA patients was 34.7 ± 12.3 years (p<0.001). WS-MRI showed that the frequency of cervical, thoracic, and lumbar spine involvement was 53.6% versus 52.3%, 75% versus 88.6%, and 60.7% versus 63.6%, respectively (p=0.70, 0.13, and 0.80). The frequency of sacroiliac joint involvement was 7.1% and 100% (p<0.001). Continuous spinal involvement accounted for 50% versus 43.2%, 60.7% versus 84.1%, and 39.3% versus 40.9% in the cervical, thoracic, and lumbar vertebrae, respectively (p=0.03). WS-MRI showed that bone marrow oedema of spinal anterior corner was observed in 50% versus 75% (p=0.03). Vertebral body and posterior attachment involvement accounted for 85.7% versus 93.2% and 14.3% versus 34.1% (p=0.3, 0.06). The frequency of bone erosion in mobile spine was 75% and 36.4%, respectively (p=0.02). The frequency of intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue swelling was 42.9% versus 18.2%, 53.6% versus 22.7%, 85.7% versus 42.2%, and 50% versus 11.4% (p=0.02, 0.00).

CONCLUSIONS

Factors differentiating the two groups at WS-MRI were bone marrow oedema of the spinal anterior corner, bone erosion, and swelling of the intervertebral disc, endplate, anterior thoracic wall, and paraspinal soft-tissue.

The comparison analysis of clinical and radiological features in SAPHO syndrome

OBJECTIVES

The aim was to comparatively assess the clinical and imaging features in patients with SAPHO syndrome.

METHODS

The clinical data, laboratory results, imaging data of forty-six SAPHO patients were reviewed and the SAPHO patients were divided into spinal involvement group and non-spinal involvement group. Fifty patients with ankylosing spondylitis were recruited as control group. The clinical and radiological features of them were analyzed and compared.

RESULTS

Thirty-four of 46 (73.9%) of all the SAPHO patients had spinal involvement. The lesions exhibited as abnormal hyper-intensity signal in vertebral bodies, vertebral body erosion or collapse, bone marrow edema, endplate inflammation, spondyldiscitis, paravertebral ossification, and facet joint involvement. Compared with patients in non-spinal involvement group, the age at disease onset was older (P = 0.033), the disease duration was longer (P = 0.048), and CRP level was elevated (P = 0.047) in patients in spinal involvement group. Compared with patients with ankylosing spondylitis, SAPHO patients were more likely to have cervical vertebra involvement (P = 0.024), endplate inflammation (P = 0.019), and spondyldiscitis (P = 0.001), but less multiple vertebral body and facet joint involvement (P = 0.002). Patients regularly received DMARDS or biologics treatment had symptoms relieved and lesions turned into chronic stage or better than before.

CONCLUSIONS

A total of 73.9% of the SAPHO patients had spinal involvement and the involvement could affect any part of the spine. Cervical vertebral involvement, endplate inflammation, and sponlypodiscitis were more common in SAPHO than in patients with ankylosing spondylitis. In SAPHO patients with spinal involvement, the disease duration was longer and the inflammatory reaction was more intensive. DMARDs and biologics may help to prevent the disease progress.

KEY POINTS

• To the best of our knowledge, this paper is the first one to comparatively study the clinical and radiological features of SAPHO syndrome, especially the characteristics of spinal involvement.

Magnetic resonance imaging of the sacroiliac joints in SpA: with or without intravenous contrast media? A preliminary report

OBJECT

Active sacroiliitis based on magnetic resonance imaging (MRI) without intravenous (I.V.) contrast material injection is considered sufficient for the diagnosis of spondyloarthritis (SpA), according to the Assessment of SpondyloArthritis International Society (ASAS) criteria. This work shows the added value of administering I.V. contrast material when evaluating the response to tumor necrosis factor (TNF) antagonists therapy, on the extension of bone marrow oedema (BMO) and pathological enhancement (osteitis/synovitis) in the sacroiliac joints (SIJs) on MRI.

MATERIALS AND METHODS

Forty-three patients (25 females and 18 males, mean age of 54 ± 16.60 years, range 22-75 years) with a clinical diagnosis of SpA and active sacroiliitis at MRI with I.V. contrast material, were considered for a follow-up MRI after 6 months of TNF antagonists therapy. Disease activity was monitored by a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) questionnaire. Descriptive statistics, Student's t test and Cohen's kappa were used. P < 0.05 was considered statistically significant.

RESULTS

Thirty-eight patients were finally included in the study; 36 of them showed an improvement on clinical assessment after therapy. Score's difference (improvement) after treatment was calculated in the MRI sequences both with and without contrast agent (respectively, mean value and range 3.18, 0-12 with contrast and 1.63, 0-7 without contrast). This improvement was statistically significant in each group (P value of 7.097e-08 with contrast and 6.741e-06 without contrast), and there was a significant difference between the two group too (P-value of 8.598e-07). Cohen's kappa for dichotomous variables showed a better agreement between the post-contrast MRI findings and BASDAI (K = 0.53, agreement = 92.11%, P = 0.0001) than MRI without contrast and BASDAI (K = 0.11, agreement = 57.89%, P = 0.06).

CONCLUSIONS

The evaluation of enhancement is a reliable tool for the assessment of the response to therapy in SIJs involvement in SpA, better than BMO; hence, it should be advised in the MRI of these patients.

MRI findings for unilateral sternoclavicular arthritis: differentiation between infectious arthritis and spondyloarthritis

OBJECTIVES

To analyze and identify magnetic resonance imaging (MRI) and clinical findings for the differentiation between infectious arthritis and spondyloarthritis in patients with unilateral sternoclavicular arthritis.

MATERIALS AND METHODS

We retrospectively collected and evaluated the magnetic resonance (MR) images of 21 patients diagnosed with unilateral sternoclavicular arthritis, including 12 with infection and nine with spondyloarthritis, between 2004 and 2017. Capsular distension, extracapsular fluid collection, periarticular muscle edema, the prevalence and distribution of bone marrow edema, and the prevalence and size of bone erosions were assessed on the MR images. Clinical data were also reviewed.

RESULTS

Capsular distension was more prominent in patients with infectious arthritis than those with spondyloarthritis (p = 0.002); extracapsular fluid collection and periarticular muscle edema were also more common in infectious arthritis than spondyloarthritis (p < 0.001, respectively); moreover, bone erosions were larger in infectious arthritis than spondyloarthritis (p = 0.023). Other findings significantly associated with infectious arthritis included advanced age (p = 0.007), an elevated C-reactive protein (CRP) level (p = 0.001), and erythrocyte sedimentation rate (ESR) (p < 0.001). The prevalence and distribution of bone marrow edema and the prevalence of bone erosions on MRI, the white blood cell count, and sex showed no significant differences between the two groups.

CONCLUSIONS

Capsular distension, extracapsular fluid collection, periarticular muscle edema, and the size of bone erosions on MRI, as well as the age, CRP level, and ESR of patients, could be helpful for differentiating infectious arthritis from spondyloarthritis involving the sternoclavicular joint.

Altered Bone Remodeling in Psoriatic Disease: New Insights and Future Directions

Psoriatic arthritis (PsA) is an inflammatory rheumatic disorder that occurs in patients with psoriasis and predominantly affects musculoskeletal structures, skin, and nails. The etiology of PsA is not well understood but evidence supports an interplay of genetic, immunologic, and environmental factors which promote pathological bone remodeling and joint damage in PsA. Localized and systemic bone loss due to increased activity of osteoclasts is well established in PsA based on animal models and translational studies. In contrast, the mechanisms responsible for pathological bone remodeling in PsA remain enigmatic although new candidate molecules and pathways have been identified. Recent reports have revealed novel findings related to bone erosion and pathologic bone formation in PsA. Many associated risk factors and contributing molecular mechanisms have also been identified. In this review, we discuss new developments in the field, point out unresolved questions regarding the pathogenetic origins of the wide array of bone phenotypes in PsA, and discuss new directions for investigation.

Imaging for Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome

Multifocal osteomyelitis and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome constitute a spectrum of disease that includes inflammatory bone lesions and dermatologic findings. Radiographic features resemble those of the spondyloarthropathies with anterior chest wall involvement. Early radiographic findings are osteodestructive with lytic lesions. Bone scintigraphy of the sternoclavicular region classically yields a 'bull's head' pattern of radionuclide uptake. Magnetic resonance imaging (MRI) can demonstrate corner lesions of vertebral bodies. Ultrasound often reveals peripheral enthesitis. Late radiographic features are usually osteoproliferative. PET/CT can identify chronic lesions. Differential diagnostic considerations include osteomyelitis and malignancy, which often prompt bone biopsy.

IL-23R and IL-17A polymorphisms correlate with susceptibility of ankylosing spondylitis in a Southwest Chinese population

The association between the IL-23R and IL-17A polymorphisms and ankylosing spondylitis (AS) in the Southwest Chinese Population is still unclear. The purpose of this study is to detect the association between IL-23R and IL-17A polymorphisms and AS. A case-control study consisting of 486 AS patients and 480 healthy controls was performed. We used the high-resolution melting methods (HRM) to genotype five selected single nucleotide polymorphisms (SNPs), rs6693831, rs7517847, rs1884444, rs10889677 in the IL-23R gene and rs2275913 in the IL-17A gene. Meanwhile, the laboratory indexes were recorded. In this study, patients with genotype CC (p = 8.574E-8) and allele C (p = 3.206E-31) on SNP rs6693831 (IL-23R) showed decreased risk of AS. The genotype TT (p = 4.551E-6) and allele T (p = 0.02) on SNP rs1884444 (IL-23R) showed significant lower risk of AS. Individuals carrying the allele A of rs2275913 showed higher morbidity of AS (p = 0.04). We first detected that rs6693831 and rs1884444 in IL-23R gene and rs2275913 in IL-17A gene have genetic association with AS.

Computed Tomography and MR Imaging in Spondyloarthritis

This article provides an overview of the computed tomography (CT) and MR imaging appearances suggestive of spondyloarthritis, with a specific emphasis on the MR imaging findings of vertebral and sacroiliac involvement, and presents relevant clinical features that assist early diagnosis. CT is a sensitive imaging modality for the assessment of structural bone changes, but its clinical utility is limited. MR imaging is the modality of choice for early diagnosis, because of its ability to depict inflammation long before structural bone damage occurs, for monitoring of disease activity, and for evaluating therapeutic response.

Whole-spine Computed Tomography Findings in SAPHO Syndrome

OBJECTIVE

We evaluated the whole-spine computed tomography (CT) findings in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome to improve our understanding of this rare disease.

METHODS

Whole-spine CT images obtained in 69 patients with SAPHO were reviewed. For each individual, a total of 25 vertebrae were evaluated for the distribution of affected vertebrae, CT manifestations of vertebral lesions, symmetry and location of distribution of the lesions on vertebrae, involvement pattern, and narrowing of adjacent intervertebral disc space. Paravertebral ligamentous ossifications, apophyseal joint disorders, and costovertebral joint disorders were also evaluated.

RESULTS

All the 69 patients with SAPHO exhibited abnormalities on whole-spine CT. Sixty-four had vertebral lesions, 52 had paravertebral ossifications, and 47 had both. The vertebral lesions were observed in 441 vertebrae, with a predilection for thoracic spine. The lesions exhibited a mixture of cortical erosion, reactive osteosclerosis of surrounding cancellous bone, and syndesmophyte. They may be confined to the vertebral corner (65.1%) or be extensive, involving the endplate (34.9%). Corner lesions could start in any part of the epiphyseal ring. The lesions were asymmetrically distributed. The affected vertebrae were more consecutively involved in a "kissing" appearance (78.2%). Intervertebral disc spaces were usually normal or mildly narrowed. There were 320 foci of paravertebral ossifications observed, with a predilection for the supraspinous ligament. Paravertebral ossifications were delicate and segmental. Ossifications throughout annulus fibrosis and apophyseal joint were not observed.

CONCLUSION

Our investigation of the distributional, morphological features and the involvement pattern of spinal lesions in patients with SAPHO demonstrated distinct CT characteristics.

Selected issues in diagnostic imaging of spondyloarthritides: psoriatic arthritis and juvenile spondyloarthritis

Spondyloarthritides (also known as spondyloarthropathies) are a group of rheumatic diseases that consists of diversified entities, i.e. ankylosing spondylitis, reactive arthritis, psoriatic arthritis, arthritis in the course of Crohn's disease and ulcerative colitis, and juvenile spondyloarthropathies. In the diagnostics of spondyloarthritides, plain radiography has played a crucial role for years due to its undisputed ability to show distinctive bony changes. Yet as those diseases often manifest themselves by soft tissue pathology and bone marrow inflammation, ultrasonography and magnetic resonance imaging are currently a subject of numerous studies in the quest for setting up diagnostic criteria, especially at early stages of inflammatory processes. In our review, we present an up-to-date insight into classifications, etiopathogenesis and imaging of psoriatic arthritis and juvenile spondyloarthritis.

Case 229: Burn-related Global Ankylosis of Interphalangeal Joints with Associated Acroosteolysis

History A 50-year-old woman presented with a 6-month history of polyarthralgia involving the left and right hands, wrists, elbows, ankles, and knees. Her pain was not associated with morning stiffness but did worsen over the course of the day. She denied experiencing fevers, chills, or mouth ulcers. She did not report paresthesias or blue discoloration of her fingers when they were exposed to cold. Her family history was remarkable for an aunt who died of systemic lupus erythematosus and for a brother with arthritis. Her medical history was remarkable for vitamin D deficiency, hypertension, and rehabilitation for burns. At clinical examination, she had mild tenderness to palpation of her joints, without associated erythema, swelling, or crepitus. Healed skin grafts were also noted. Blood chemistry tests revealed a rheumatoid factor of 8.5 IU/mL (normal range, 0-13.9 IU/mL), an erythrocyte sedimentation rate of 2 mm/hr (normal range, 0-40 mm/hr), and a C-reactive protein value of 0.4 mg/L (3.8 nmol/L) (normal range, 0-4.9 mg/L [0-46.7 nmol/L]). Antinuclear antibodies test results were negative. Radiography of the right and left hands was performed.

Spinal fractures in patients with ankylosing spondylitis

The ankylosed spine is prone to fracture even after minor trauma due to its changed biomechanical properties. The two central features of ankylosing spondylitis (AS) that promote the pathological remodeling of the spine are inflammation and new bone formation. AS is also associated with osteoporosis that is attributed to an uncoupling of the bone formation and bone resorption processes. Therefore, bone resorption occurs and promotes weakening of the spine as well as increased risk of vertebral fractures which can be hugely different in terms of clinical relevance. Even in the presence of symptomatic clinical vertebral fractures, the diagnosis can be overruled by attributing the pain to disease activity. Furthermore, given the highly abnormal structure of the spine, vertebral fracture diagnosis can be difficult on the basis of radiography alone. CT can show the fractures in detail. Magnetic resonance imaging is considered the method of choice for the imaging of spinal cord injuries, and a reasonable option for exclusion of occult fractures undetected by CT. Since it is equally important for radiologists and clinicians to have a common knowledge base rather than a compartmentalized view, the aim of this review article was to provide the required clinical knowledge that radiologists need to know and the relevant radiological semiotics that clinicians require in diagnosing clinically significant injury to the ankylosed spine.

Application of Diffusion-Weighted Imaging in the Detection of Active Sacroiliitis and the Comparison of Apparent Diffusion Coefficient and Relative Apparent Diffusion Coefficient Values

Objectives

This study aims to evaluate the role of diffusion-weighted imaging in detection of active sacroiliitis and compare the apparent diffusion coefficient (ADC) and normalized relative ADC (r-ADC) values by using vertebra and iliac wings as reference organs.

Patients and methods

The study included 56 patients (26 males, 30 females; mean age 37.7±10.1 years; range 18 to 66 years) with chronic back pain and without history of sacroiliitis who underwent magnetic resonance imaging. T2-weighted spectral presaturation with inversion recovery, contrast-enhanced T1-weighted spectral presaturation with inversion recovery, and diffusion-weighted (b values: 0 and 600 s/mm2) images were obtained. All images were evaluated by two different radiologists for interobserver variability. All individuals were grouped in either mechanical low back pain (control group) or active sacroilitis (disease group) groups according to the presence or absence of MRI findings of active sacroilitis. ADC values of both surfaces were measured from normal and affected areas of joints. Also, ADC values of L5 vertebra and iliac wings were measured as reference organs to calculate r-ADC values.

Results

Mean ADC and r-ADC values measured from lesions were significantly higher than that of normal appearing bone marrow areas in both patients with mechanical low back pain (n=17) and active sacroiliitis (n=39). Both ADC values and r-ADC values could differentiate active lesions from normal appearing bone marrow areas as well as contrast-enhanced T1-weighted images. According to r-ADC values calculated with the L5 vertebra, unaffected portions of bone marrow areas in patients with sacroiliitis were normalized whereas r-ADC remained higher than normal in affected portions of the bones.

Conclusion

Diffusion-weighted imaging is a fast, sensitive magnetic resonance imaging sequence in detection of active sacroiliitis. It does not require contrast agent and can be safely used as an adjunct to conventional magnetic resonance images. r-ADC is also highly sensitive in detecting active sacroiliitis and may be used as an alternative to standard ADC measurements for the demonstration of inflammation. It helps eliminate individual bone marrow differences by using patients' own normal bone marrow measurements and increases diagnostic accuracy.

Diagnostic imaging of psoriatic arthritis. Part I: etiopathogenesis, classifications and radiographic features

Psoriatic arthritis is one of the spondyloarthritis. It is a disease of clinical heterogenicity, which may affect peripheral joints, as well as axial spine, with presence of inflammatory lesions in soft tissue, in a form of dactylitis and enthesopathy. Plain radiography remains the basic imaging modality for PsA diagnosis, although early inflammatory changes affecting soft tissue and bone marrow cannot be detected with its use, or the image is indistinctive. Typical radiographic features of PsA occur in an advanced disease, mainly within the synovial joints, but also in fibrocartilaginous joints, such as sacroiliac joints, and additionally in entheses of tendons and ligaments. Moll and Wright classified PsA into 5 subtypes: asymmetric oligoarthritis, symmetric polyarthritis, arthritis mutilans, distal interphalangeal arthritis of the hands and feet and spinal column involvement. In this part of the paper we discuss radiographic features of the disease. The next one will address magnetic resonance imaging and ultrasonography.

Presumptive Late-Onset Ankylosing Spondylitis Simulating Osteoblastic Skeletal Metastasis in a Patient With a History of Prostate Carcinoma: A Diagnostic Challenge

OBJECTIVE

The purpose of this report is to present a presumptive case of ankylosing spondylitis with late stage progression that simulated osteoblastic metastasis in a patient with a history of prostate carcinoma.

CLINICAL FEATURES

A 67-year-old white man presented to a chiropractic clinic complaining of severe and worsening acute low back pain and right foot "numbness." Further questioning also revealed a history of prostate carcinoma.

INTERVENTION AND OUTCOME

Imaging examination revealed a sclerotic pedicle and increased uptake of radiopharmaceutical on a nuclear medicine bone scan highly suggestive of osteoblastic skeletal metastasis. Further evaluation, however, revealed that the bone sclerosis was not the result of skeletal metastasis, but more consistent with a seronegative spondyloarthritis such as ankylosing spondylitis.

CONCLUSION

This report describes a presumptive case of ankylosing spondylitis simulating skeletal metastasis in a patient with a past medical history of prostate cancer. This atypical presentation illustrates the inherent uncertainty of diagnosis and how that uncertainty can be challenging in clinical practice. It also reinforces that it is critical for healthcare providers to consider a wide spectrum of differential diagnoses to avoid misdiagnoses and inappropriate interventions.

Gingival pustules and sterile diffuse sclerosing osteomyelitis as a feature of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome

Synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome represents the rare co-occurrence of sterile inflammatory osteoarticular disease in association with a variety of cutaneous manifestations. Oral involvement is uncommon. The etiology of SAPHO is complex and is likely the combined result of infectious, genetic, and immunologic factors. Due to diverse clinical presentations, SAPHO is difficult to diagnose. Here, we describe the case of a 74-year-old man, who had a history of SAPHO syndrome and presented with gingival pustules and sterile diffuse sclerosing osteomyelitis of the mandible. This is the first case report describing neutrophilic mucositis as a feature of SAPHO.