Imaging of the sacroiliac joint involvement in seronegative spondylarthropathies

Involvement of the sacroiliac joints is the first predominant finding of all seronegative spondylarthropathies (SpA) subsets, such as ankylosing spondylitis, psoriatic arthritis, and undifferentiated SpA. Although conventional radiography is indicated in the initial evaluation of sacroiliac joints diseases, it is often insensitive for demonstrating the early changes of sacroiliitis, so other imaging techniques typically are often necessary to clarify the pathology and for establishing the early diagnosis of seronegative SpA. Other imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US), and bone scintigraphy have improved visualization of inflammatory changes at the sacroiliac joints (SIJ). CT scans are indicated for disease processes in which bony destruction or ossification may occur. MRI has been proposed as an imaging method to detect sacroiliitis earlier. MRI can identify both inflammation and structural changes caused by inflammation, while radiographs show only structural changes. MRI may be particularly useful in making a diagnosis of SpA. Musculoskeletal US has an increasing and relevant role in the evaluation of SpA mainly for its ability to assess joint and periarticular soft tissue involvement and in particular for its capacity to detect enthesitis. US assessment in general is safe, noninvasive, and comparably cheap, showing itself as a complimentary tool to clinical evaluation in SpA; nevertheless, it is very user dependent. Bone scintigraphy is at most of limited diagnostic value for the diagnosis of established AS, including the early diagnosis of probable/suspected sacroiliitis. The main aim of this study is to introduce the clinical and radiological aspects of the SIJ involvement in SpA, particularly the contribution of the different imaging techniques.     

脊柱关节病患者骶髂关节细针活检的病理表现及其临床意义

目的了解骶髂关节(SIJ)炎的病理表现,提高强直性脊柱炎(AS)的早期诊断水平。方法对96例脊柱关节病(SpA)患者的SIJ进行CT导引下的细针活检,3例非SpA死亡病例为对照组。记录临床资料进行分析。结果76例SpA的SIJ存在炎症表现,包括骨髓炎、血管翳形成和炎性细胞浸润,软骨下骨板破坏,软骨变性、破坏,滑膜炎,附着点炎等。其中45例0～Ⅰ级CT下SIJ炎均存在骨髓炎、软骨下骨板炎、软骨变性等改变;0级CT下SIJ炎的滑膜无病理改变,而部分Ⅰ级和所有≥Ⅱ级SIJ炎滑膜可见炎症;软骨破坏和骨化发生率以0～Ⅰ级最低,且仅见于软骨下骨板侧,关节面侧未见破坏;骨质硬化也是0～Ⅰ级最少见;附着点炎仅见于部分≥Ⅱ级SIJ炎;炎性细胞浸润程度Ⅳ级最低。45例0～Ⅰ级CT下SIJ炎的SpA经病理检查诊断为AS;其平均病程显著短于≥Ⅱ级者。结论0级CT下SIJ炎时SIJ已可有炎症存在。SIJ炎可能自骨髓开始,继而血管翳形成,软骨下骨板破坏,软骨变性、破坏,最后纤维化、骨化而导致关节融合。滑膜炎和附着点炎不是SIJ炎的最早改变。病理检查有利于AS的早期诊断和鉴别诊断。     

强直性脊柱炎骶髂关节内皮质激素注射疗效观察

目的了解强直性脊柱炎(AS)骶髂关节(SIJ)内皮质激素注射的疗效.方法患者取俯卧位,在CT导引下穿刺SIJ滑膜部,取组织标本后,在CT导引下原路进入SIJ,每侧注入丙酮缩去炎舒松15mg.记录分析病人术前、术后临床资料.结果28例中22例(78.6%)疼痛明显减轻,晨僵、夜间痛、SIJ压痛、"4”征、ESR升高及需使用NSAIDs的例数均较术前明显减少.所有SIJ标本均有炎症表现.结论SIJ关节内注射长效激素,可作为对NSAIDs不耐受或无效的AS和uSpA病人的一种有效的缓解腰背痛手段,同时uSpA病人SIJ病理标本的获得,有助于早期诊断.     

Incidental computed tomography sacroiliitis: clinical significance and inappropriateness of the New York radiological grading criteria for the diagnosis

The clinical implications of computed tomography (CT) detected sacroiliac joint (SIJ) changes compatible with sacroiliitis has been rarely discussed in the literature. The aim of the present study was to describe prevalence and clinical correlations of sacroiliitis, noted incidentally by abdominal CT in patients referred for non-musculoskeletal complaints, utilizing the New York radiological grading criteria for reference. Five hundred ninety-eight CT scans of the abdomen of patients 18–55 years old, performed at a community medical center, were prospectively examined for the presence of imaging changes consistent with sacroiliitis. Patients with the evidence of bilateral sacroiliitis of grade ≥2 were interviewed and underwent a rheumatologic examination. Twenty-two patients (13 females) were enrolled. Only eight patients (six males) had a history and clinical picture compatible with previously undiagnosed axial spondyloarthritis (SpA). Only the presence of erosions/joint space irregularity and/or inhomogeneous osseous sclerosis around SIJs on CT correlated with the clinical diagnosis of axial SpA. Dense homogenous osseous sclerosis was unrelated to axial SpA and was seen almost exclusively in females. The prevalence of incidental CT sacroiliitis is low, while the New York radiological grading criteria for diagnosing sacroiliitis may be inappropriate for CT imaging. CT noted erosions of the SIJ appear to be a reliable diagnostic sign of sacroiliitis, while the significance of the osseous sclerosis, seen on CT adjacent to SIJs requires better understanding.     

骶髂关节病变病理学与影像学诊断的相关性

目的通过了解骶髂关节炎病理特点,并以病理结果为标准,探讨病理表现与放射性核素单光子发射计算机断层成像术(single-photon emission computed tomography,SPECT)、磁共振显像(magnetic resonance imaging,MRI)、计算机断层扫描(computed tomography,CT)、X线等影像学检查的关系。方法对中轴型脊柱关节炎患者进行CT引导下骶髂关节(sacroiliac joint,SIJ)穿刺,所得组织进行病理检查,并同时行SIJ的SPECT、MRI、CT和X线检查,按组织病理结果分为SIJ炎组和无炎性反应组。结果 36例患者获得组织有软骨、软骨下骨板、关节滑膜、骨髓、肌腱或韧带附着点等。获得率以软骨为最高,继以软骨下骨板、关节滑膜、骨髓和韧带附着点,各占92%、83%、75%、72%、22%;其中28例(2836,78%)患者SIJ炎病理变化包括软骨(93%)和软骨下骨板改变(75%)、滑膜炎(64%)、骨髓炎(46%)、附着点炎(32%),8例(22%)未发现有SIJ炎改变。MRI示29例(81%)患者共56个SIJ可见不同程度的异常信号改变,软骨线改变、软骨下骨板改变、骨髓水肿、脂肪沉积、骨质硬化分别为82%、71%、65%、59%、76%;SPECT示29例(81%)共52个SIJ可见骶髂关节感兴趣区的放射性比值有不同程度的升高,23例(64%)CT阳性,19例(53%)X线阳性。以病理结果为标准,SPECT、MRI、CT、X线的阳性预测值分别为89.6%、93.1%、95.6%、94.7%,敏感性分别为92.8%、96.4%、73.3%、64.2%,特异性分别62.5%、75.0%、87.5%、87.5%。4种诊断方法的受试者工作特征曲线下面积分别为0.79、0.84、0.83、0.76。结论病理检查是诊断Sl J炎和活动性炎性反应的主要方法。MRI和SPECT的相互补充,能提高骶髂关节活动性炎症的敏感性和特异性。MRI和SPECT的诊断价值与CT和X线相当,并可通过对炎症的活动度进行量化,有利于随访和疗效的评价,是诊断SIJ炎重要的辅助手段。     

Magnetic resonance imaging in rheumatic disorders of the spine and sacroiliac joints

OBJECTIVE: To review the value of magnetic resonance imaging (MRI) in diagnosis and evaluation of rheumatic diseases of the spine and sacroiliac joints. METHODS: A review of the literature on MRI of the spine and sacroiliac joints in rheumatoid arthritis (RA), ankylosing spondylitis (AS), infectious spondylodiscitis, infection of the sacroiliac joint (SIJ), gout, calcium pyrophosphate deposition disease, nontraumatic vertebral compression fractures, insufficiency fracture of the sacrum, avascular necrosis of the vertebral body, sarcoidosis, and Paget's disease was performed. The reports were obtained from a Medline search. RESULTS: In RA, AS, and crystal deposition disease, synovial tissue, atlantoaxial and subaxial subluxations, crystal deposition, and neurologic compromise can be adequately diagnosed with MRI of the cervical spine. Studies on MRI of SIJs in AS indicate that MRI enables early diagnosis of sacroiliitis. In most cases of infectious spondylodiscitis, avascular necrosis of the vertebral body, nontraumatic vertebral compression fractures, and insufficiency fractures of the sacrum characteristic findings on MRI suggest the correct diagnosis. Moreover, soft tissue abnormalities and neurologic compromise can be visualized. In infection of the SIJ, MRI shows findings suggesting an inflammatory process. In Paget's disease, MRI does not provide additional information as compared with plain radiography (PR) or computed tomography (CT). CONCLUSION: In evaluation of spinal and SIJ abnormalities in many rheumatic diseases, MRI, in addition to PR, can replace conventional tomography, CT, and myelography. Moreover, MRI can visualize soft tissue abnormalities and neurologic compromise without use of intrathecal contrast.     

Baseline sacroiliac joint magnetic resonance imaging abnormalities and male sex predict the development of radiographic sacroiliitis

We evaluated the relationship between the baseline sacroiliac joint (SIJ) magnetic resonance imaging (MRI) findings and the development of radiographic sacroiliitis and tested their prognostic significance in cases of ankylosing spondylitis. Patients who had undergone an SIJ MRI at the rheumatology department were identified. Individuals for whom pelvic X-rays were available after at least 1 year of MRI were included in the analysis. All radiographs and MRI examinations were scored by two independent readers. Medical records of the patients were reviewed to obtain potentially relevant demographic and clinical data. We identified 1,069 SIJ MRIs, and 328 fulfilled our inclusion criteria. Reliability analysis revealed moderate to good inter- and intra-observer agreement. On presentation data, 14 cases were excluded because they had unequivocal radiographic sacroiliitis at baseline. After a mean of 34.8 months of follow-up, 24 patients developed radiographic sacroiliitis. The presence of active sacroiliitis (odds ratio (OR) 15.1) and structural lesions on MRI (OR 8.3), male sex (OR 4.7), fulfillment of Calin’s inflammatory back pain criteria (P?=?0.001), and total MRI activity score (P?<?0.001) were found to be related to the development of radiographic sacroiliitis. By regression modeling, the presence of both active inflammatory and structural damage lesions on MRI and male sex were found to be predictive factors for the development of radiographic sacroiliitis. Our present results suggest that the occurrence of both active inflammatory and structural lesions in SIJs revealed by MRI is a significant risk factor for radiographic sacroiliitis, especially in male patients with early inflammatory back pain.     

Imaging of Sacroiliitis

Inflammation of one or both sacroiliac joints is a characteristic feature of patients with spondyloarthropathies (SpA). Sacroiliitis often leads to inflammatory back pain (IBP). IBP and asymmetric peripheral arthritis of the lower limbs are the main clinical symptoms and criteria for classification and diagnosis of SpA in which sacroiliac joints are uni- or bilaterally affected with an intensity ranging from mild to very severe inflammation resulting in partial or complete ankylosis Sacroiliitis is a very frequent feature of undifferntiated SpA. In ankylosing spondylitis (AS) inflammation in the axial skeleton occurs rarely in the absence of sacroiliitis. Objective evidence of sacroiliitis obtained by imaging procedures, especially x-rays, has always been part of diagnostic and classification criteria for AS. This is in contrast to spinal radiography which, however, has been recently included in a core set of outcome items to be assessed in clinical studies. In early and acute stages of sacroiliitis the diagnosis can be difficult because conventional radiographs - which are known to have considerable intra- and interobserver variability - may be normal. Since IBP is not a specific indicator of sacroiliitis there is need for valuable imaging techniques. Scintigraphy lacks specificity. Computed tomography (CT) is a very good method to demonstrate already established bony changes and magnetic resonance imaging (MRI) has the advantage of combining a good visualisation of the complicated anatomy of the sacroiliac joint with the ability to localise different degrees of inflammation and oedema and prove a possible spread to muscles as it occurs in septic sacroiliitis, an important differential diagnosis. Received: 3 March 1999 / Accepted: 3 March 1999     

Computed tomography in the diagnosis of early ankylosing spondylitis

Computed tomography (CT) was compared with plain radiography and quantitative sacroiliac (SI) scintigraphy in 28 patients with early ankylosing spondylitis (AS) of less than or equal to 10 years duration. Compared with conventional radiography, CT improved delineation of the SI joints and revealed more abnormalities and higher grades of sacroiliitis; this was significant in patients with early AS of less than or equal to 3 years duration. Quantitative sacroiliac scintigraphy showed higher SI joint: sacrum ratios of radioisotope uptake in patients with AS compared with controls. However, its diagnostic usefulness was limited by the frequency of inconsistent results and the lack of specificity. CT examination of the SI joints may be a useful adjunct in the diagnosis of early AS.     

结缔组织生长因子及I型和Ⅲ型胶原在脊柱关节病骶髂关节组织中的表达

目的 了解脊柱关节病(SpA)患者骶髂关节中结缔组织生长因子(CTGF)、I型胶原、Ⅲ型胶原的表达情况,探讨CTGF在spA关节软骨纤维化、骨化、关节强直中的作用.方法 30例spA患者(17例双侧影像学骶髂关节炎≥Ⅱ级,13例影像学骶髂关节炎Ⅰ级)均接受CT引导下骶髂关节穿刺活检术,取得骶髂关节组织.组织标本均行苏木素一伊红(HE)染色确认存在骶髂关节炎后,通过免疫组织化学染色方法,标记CTGF、Ⅰ型胶原及Ⅲ型胶原的表达情况.统计学方法采用单因素方差分析和t检验.结果 30例SpA患者骶髂关节组织中CTGF主要在血管翳炎症细胞及骨髓细胞的胞质中高度表达,阳性细胞数明显多于正常组织对照组[(57.9±42.4)腐倍视野和(2.7±2.5),高倍视野);Ⅰ型胶原及Ⅲ型胶原明显沉积于骨、部分软骨及韧带,平均吸光度均明显高于对照组(分别为0.298±0.080和0.044±0.024;28.254±41.165和0.105±0.054).结论 SpA骶髂关节中存在CTGF的高表达,Ⅰ型胶原及Ⅲ型胶原的沉积增多,提示CTGF参与了SpA骶髂关节局部胶原沉积、软骨纤维化变性过程,可能在SpA关节软骨纤维化、关节强直中起重要的作用.

Abstract：

Objective To investigate the expression of connective tissue growth factor(CTGF),coll agen I and collagen Ⅲ in sacroiliac joint(SIJ)of patients with spondyloarthropathy(SpA).Methods Thirty patients with SpA,including 17 patients with grade Ⅱ saeroiliitis and 13 patients with grade Ⅰ sacroiliitis,were performed on CT guided needie biopsy of SIJ.After sacroiliitis were confirmed by staining with hematoxylin and eosin in sacroiliac joint tissue sample,immunohistochemical assay was performed to determine the expression of CTGF,collagen Ⅰ and collagen Ⅲ in sacroiliac ioint tissue.Univariate Chi-square test was used for data comparison between multiple groups and t-test was used for two group data comparison.Results Contrast to healthy controls,CTGF were found upexpressed on the cytoplasm of inflammatory cells in pannus and bone marrow of sacroiliac tissue samples of patients with SpA,while collagen I and collagen Ⅲ were found up-expressed in bone,cartilage and ligament tissue[(57.9±42.4)/HP vs(2.7±2.5)/HP P<0.05,0.298±0.080 vs 0.044±0.024 and 28.254±41.165 vs 0.105±0.054.P<0.05 respectively].Conclusion CTGF,collagen Ⅰ and collagen Ⅲ are up-expressed in SIJ of SpA patients.CTGF may play an important role in articular cartilage fibrosis and ossification of SpA.     

Magnetic resonance imaging in the detection of sacroiliitis.

The value of magnetic resonance imaging (MRI) in establishing the diagnosis of sacroiliitis was studied in 20 patients with established or suspected disease on conventional radiographs and in 10 healthy subjects. Coronal T1 weighted, axial T2 weighted and proton density MRI images of the sacroiliac joints in addition to plain film radiographs were obtained. All films were graded from 0 to 4 according to the modified New York criteria and independently for changes in joint width, erosions, sclerosis and ankylosis. Using the modified New York criteria, more abnormalities were detected by MRI than by conventional radiography (p = 0.04). This was due to the detection of definite abnormalities (grades 2-4) by MRI in joints that were graded normal or suspicious (grades 0-1) on plain films (p = 0.01). MRI tended to be superior to plain films in visualizing erosions. Only MRI detected abnormalities of articular cartilage (19 patients) and in subchondral bone marrow (7 patients). The latter 2 types represented fatty infiltration and inflammatory change. Intraobserver and interobserver variation were similar for the interpretation of MRI scans and plain film radiographs. These results suggest that MRI detects changes of established sacroilitis. Due to its ability to directly image articular cartilage it may be particularly useful in patients with early disease.     

Clinical sequelae and sacroiliac joint changes by computed tomography after recovery from septic sacroiliitis

Summary Nine cases of septic sacroiliitis were re-examined clinically and by CT after a follow-up period of 1.5–7 years. At the final ckeck-up, six of the patients were asymptomatic, while pain could be provoked by palpation or compression in three cases. The sacroiliac joint CT findings were considered normal in two cases. Joint space narrowing, subchondral sclerosis, cysts, erosions, ankylosis and/or osteophytes were detected in seven cases. We conclude that recovery from septic sacroiliitis is good although destructive and degenerative changes often develop as sequelae of an osteolytic involvement.     

Atlas of MRI findings of sacroiliitis in pediatric sacroiliac joints to accompany the updated preliminary OMERACT pediatric JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system: Part II: Structural damage lesions

Magnetic resonance imaging (MRI) is the imaging modality of choice for identifying sacroiliitis in juvenile idiopathic arthritis (JIA). Besides active lesions of sacroiliitis, of which bone marrow edema (BME) is the key feature, structural damage lesions can also be detected. Structural changes include erosion, sclerosis, fat lesion, backfill and ankylosis, and are more common at later stages. Systematic MRI assessment of inflammation and structural damage may aid in monitoring the course of the disease and evaluating treatment options. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the SIJ in the pediatric population, as well as the different MRI features of structural damage of sacroiliitis. This atlas can serve as a reference for assessing structural lesions of SIJ arthritis according to the updated preliminary JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system proposed by the MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT). The atlas is intended to be read in conjunction with its companion Part 1, Active Lesions.     

Atlas of MRI findings of sacroiliitis in pediatric sacroiliac joints to accompany the updated preliminary OMERACT pediatric JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system: Part I: Active lesions

Magnetic resonance imaging (MRI) is an increasingly important tool for identifying involvement of the sacroiliac joints (SIJ) in juvenile idiopathic arthritis (JIA). The key feature for diagnosing active sacroiliitis is bone marrow edema (BME), but other features of active arthritis such as joint space inflammation, inflammation in an erosion cavity, capsulitis and enthesitis can be seen as well. Structural changes may also be seen. Systematic MRI assessment of inflammation and structural damage may aid in monitoring the disease course, choice of therapeutics and evaluating treatment response. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the SIJ in the pediatric population, as well as the different MRI features of SIJ inflammation. This atlas demonstrates fundamental MRI disease features of active inflammation in a format that can serve as a reference for assessing SIJ arthritis according to the updated preliminary JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system proposed by the MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT). The atlas is intended to be read in conjunction with its companion Part 2, Structural Lesions.     

Comparison of radiography, CT and MR imaging in detection of arthropathies in patients with haemophilia

Summary. To compare magnetic resonance (MR) imaging, computed tomography (CT) and radiography for the detection of arthropathies in patients with haemophilia. Forty‐one symptomatic joints in 14 men with haemophilia, ages 11–24 years (mean age 17.5 ± 3.9 years) were examined with radiography, CT and MR. Images of each joint were acquired on the same day. The precontrast MR examination obtained coronal spin‐echo T1 images and gradient echo with rephasing T2* images, as well as sagittal, axial gradient echo with rephasing T2* images using a low‐field‐strength 0.3‐T MR imager. For the postcontrast MR examination, coronal, sagittal and axial images were acquired using the same precontrast T1 sequence. Thirteen joints were also examined on enhanced MR. The severity of damage was classified using conventional radiographical staging. Severely affected haemophilic arthropathy (HA) patients (stage 5) were excluded. Findings of soft tissue swelling, osteoporosis, epiphyseal overgrowth, joint erosion, cysts, joint space narrowing, bone marrow oedema, joint effusion, haemorrhage, synovial hypertrophy and widened intercondylar notches as well as anterior and posterior cruciate ligaments (for the knee) were used in all imaging comparisons. The joints were classified by radiographical criteria into stage 0 (n = 5), stage 1 (n = 7), stage 2 (n = 6), stage 3 (n = 8) and stage 4 (n = 15). Soft tissue swelling or joint effusion was observed in 33 joints on radiographs, in 34 on both CT and MR; joint erosions were observed in 34 joints on MR, 33 on CT and 20 on radiographs. Joint cysts appeared in 21 joints on MR, 18 on CT and 9 on radiographs. Significant differences in detection of erosion and cysts were found between radiography and CT (P < 0.05) and radiography and MR imaging (P < 0.05), not between CT and MR (P > 0.05). MR was better for detecting foci of both erosion and cysts than CT and radiography, and CT was better than radiography. MR imaging, CT and radiography were equally effective in showing the changes of epiphyseal overgrowth in 26 joints, joint space narrowing in 14 joints and widened intercondylar notches in 20 knee joints. However, only MR imaging detected tears in 17 anterior and 13 posterior cruciate ligaments in the 20 knee joints with widened intercondylar notches. Bone marrow oedema in 14 joints, haemorrhage in 34 joints and synovial hypertrophy in 27 joints were seen on MR images, but not on CT or radiography. MR imaging is superior to CT and conventional radiography for detecting abnormal changes and should be considered the first choice among imaging modalities in evaluating HAs.     

磁共振成像对早期骶髂关节炎的诊断价值研究

目的了解磁共振成像(MRI)在早期骶髂关节炎诊断中的意义。方法对82例炎症性腰背痛或不对称性下肢滑膜炎患者的骶髂关节CT扫描、MRI平扫以及病理检查结果进行分析比较。结果45例病理证实的早期骶髂关节炎中,69%(31/45)MRI显示骶髂关节存在炎症性改变。但17例病理检查骶髂关节无炎症性改变者,也有59%(10/17)MRI表现不同程度骶髂关节炎症性改变。以病理检查结果为依据,MRI对早期骶髂关节炎诊断的敏感性、特异性分别为69%和41%。结论MRI对早期骶髂关节炎的诊断有一定的敏感性,但特异性不高,临床应用要慎重考虑。     

Imaging in spondyloarthropathies

Seronegative spondyloarthropathies comprise a group of inflammatory arthritides, which consists of ankylosing spondylitis, psoriatic arthritis, reactive arthritis (Reiter’s syndrome), enteropathic arthritis, and undifferentiated spondyloarthropathy. All of them share common laboratory, clinical, and imaging findings, with characteristic involvement of the sacroiliac joints, spine, and, to various degrees, peripheral joints. For many years, conventional radiography was the mainstay for definitive diagnosis of sacroiliitis and for follow-up of the anatomic changes in the spine, peripheral joints, and entheses. Conventional radiographs remain the imaging investigation of choice; however, they are unable to detect early inflammatory changes of sacroiliitis, which are important for establishing a diagnosis without delay. Other imaging modalities, such as computed tomography, bone scintigraphy, magnetic resonance imaging, and ultrasonography have improved the capabilities of detecting early disease and became useful adjuncts to plain films. In addition, they also have enabled more accurate detection of pathology at various anatomic sites of the musculoskeletal system predominantly involved in spondyloarthropathies. This article will review and highlight the role of each of these modalities in the assessment of the axial and peripheral skeleton in seronegative spondyloarthropathies.     

Imaging of psoriatic arthritis

Imaging of psoriatic arthritis (PsA) is important for two reasons: the differential diagnosis from other arthritides and the assessment of structural damage that can be inhibited by the new drugs such as the anti-TNFalpha agents. Plain film radiographic findings of peripheral arthritis have been important in elaborating the concept of PsA as a separate disease entity. Characteristic aspects of psoriatic peripheral arthritis help the differentiation from rheumatoid arthritis. High-resolution ultrasonography (US), US combined with power Doppler (PDUS) and magnetic resonance imaging (MRI) can be used to image joint synovitis of PsA. Radiologic features of spondylitis associated with psoriasis are similar to spondylitis associated with reactive arthritis and differ from those of primary ankylosing spondylitis (AS) and the spondylitis associated with inflammatory bowel disease. MRI is very sensitive for the early diagnosis of sacroiliitis. There have been no MRI studies on the spine of patients with PsA. In primary AS bone oedema in the vertebral bodies is an indicator of active disease and can ameliorate during anti-TNFalpha therapy. Historically, plain film radiography have played a pivotal role in defining enthesitis lesions of SpA. However, entheseal bone changes appear late. US and MRI have proved to be a highly sensitive and non invasive tools. Recent US and MRI studies on both finger and toe dactylitis have established that dactylitis is due to flexor tenosynovitis and marked adjacent soft tissue swelling with a variable degree of small joint synovitis. There is no evidence of enthesitis of the insertion of the flexor digitorum tendons and of the attachment of the capsule of the digit joints.     

Imaging in rheumatoid arthritis

The optimal management of rheumatoid arthritis (RA) requires tools that allow early and accurate disease diagnosis, prediction of poor prognosis and responsive monitoring of therapeutic outcomes. Conventional radiography has been widely used in both clinical and research settings to assess RA joint damage due to its feasibility, but it has limitations in early disease detection and difficulty distinguishing between active treatments in modern trials. Imaging modalities such as magnetic resonance imaging (MRI) and ultrasound (US) have the advantage of detecting both joint inflammation and damage and hence they can provide additional and unique information. This can be especially useful in the context of early and/or undifferentiated joint disease when detection of soft tissue and bone marrow abnormalities is desirable. This review focusses on the recent literature concerning modern imaging, and provides clinicians with an insight into the role of imaging in modern RA diagnosis, prognosis and monitoring.