Power Doppler sonography in the assessment of synovial tissue of the knee joint in rheumatoid arthritis: a preliminary experience

Inflammatory low back pain: high negative predictive value of contrast-enhanced color Doppler ultrasound in the detection of inflamed sacroiliac joints

OBJECTIVE

To determine the value of microbubble contrast agents for color Doppler ultrasound (CDUS) compared with magnetic resonance imaging (MRI) in the detection of active sacroiliitis.

METHODS

An observational case-control study of 103 consecutive patients (206 sacroiliac [SI] joints) with inflammatory low back pain according to the Calin criteria and 30 controls (60 SI joints) without low back pain was conducted at the University Hospital of Innsbruck. All patients and controls underwent unenhanced and contrast-enhanced CDUS and MRI of the SI joints. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of unenhanced and contrast-enhanced CDUS were evaluated.

RESULTS

Forty-three patients (41%) with 70 of 206 SI joints (34%) and none of the controls nor the 60 control SI joints demonstrated active sacroiliitis on MRI. Unenhanced CDUS showed a sensitivity of 17%, a specificity of 96%, a PPV of 65%, and an NPV of 72%; contrast-enhanced CDUS showed a sensitivity of 94%, a specificity of 86%, a PPV of 78%, and an NPV of 97%. Detection of vascularity in the SI joint was increased by contrast administration (P < 0.0001). Clustered receiver operating curve analysis demonstrated that enhanced CDUS (A(z) = 0.89) was significantly better than unenhanced CDUS (A(z) = 0.61) for the diagnosis of active sacroiliitis verified by MRI (P < 0.0001; 2-sided test).

CONCLUSION

Microbubble contrast-enhanced CDUS is a sensitive technique with a high NPV for detection of active sacroiliitis compared with MRI.

Doppler ultrasound findings in healthy wrists and finger joints before and after use of two different contrast agents

OBJECTIVE

To examine the effect of contrast agents on Doppler ultrasound findings in the synovial membrane in the wrist and fingers of healthy volunteers.

MATERIALS AND METHODS

Eleven healthy subjects were included in the study (5 women and 6 men, mean age 38 years, range (20-60)). They had no clinical signs of inflammatory or degenerative joint diseases. A total of 66 joints were examined-6 joints for each subject: wrist and metacarpophalangeal (MCP) joints 1-5-before contrast injection and after Levovist and SonoVue injection with a 30 minute interval.

RESULTS

Colour Doppler activity was detected in 10/55 (18%) MCP joints before contrast injection and in 29/55 (53%) and 28/55 (51%) joints after Levovist (p<0.0001) and SonoVue injection (p = 0.0001), respectively. A significant increase in Doppler activity in the radial (p<0.05) and ulnar (p = 0.01) parts of the wrist joint was detected only after SonoVue injections. With spectral Doppler no difference was found in the resistive index (RI) in the vessels measured before as compared with those only detected after contrast injection.

CONCLUSION

The number of joints with colour Doppler activity in healthy volunteers was increased by the use of contrast agents. No changes in RI were detected. The value of contrast agents remains to be demonstrated in inflammatory diagnostics.

Normal anatomy of the heel entheses: anatomical and ultrasonographic study of their blood supply

The purpose of this study was first to determine the normal blood supply of the heel entheses with cadaver injection, and second, to identify by means of ultrasound (US) this blood supply in healthy volunteers before and after the intravenous injection of a US contrast agent (SonoVue). Twenty cadaver lower limbs were cut into sagittal, coronal, or axial sections after the injection of a red-colored gelatin solution. Ten anatomical samples were selected for histology. Then 10 healthy volunteers were enrolled in a contrast-enhanced ultrasonography study (CUS). Calcaneal tendon and plantar aponeurosis entheses were studied first without any contrast-agent (B-mode, power Doppler). A single dose (2.4 ml) of the contrast agent was then administered for studying each enthesis of the right foot. The operators had to look for blood flow within the entheses and in the adjacent soft tissues. Anastomotic transverse branches were seen macroscopically at the back of the calcaneal tendon, giving some capillaries penetrating the enthesis. None of these vessels could be seen with CUS. In contrast, a high-density vascular network could be detected in Kager's triangle with CUS. No blood vessel could be seen within the plantar aponeurosis enthesis, either macroscopically or microscopically. No evidence of entheseal vascularization was found with any contrast-enhanced imaging technique. Inferior branches of the lateral plantar artery were seen on coronal and sagittal sections of the hindfoot, and could be detected with CUS. These arterioles were running toward the anterior aspect of the calcaneal tuberosity, near the plantar aponeurosis insertion. In conclusion, no vascularization was detected with CUS at the cortical bone insertion of normal heel entheses. However, some vascularization could be seen in the immediate vicinity of heel entheses. The latter feature has to be kept in mind, as it may represent a pitfall for the diagnosis of early inflammatory changes in patients, especially those with seronegative spondylarthropathies.

Imaging in early arthritis

Imaging can play a vital role in the evaluation of patients with early arthritis. Various imaging methods can be utilized to aid with diagnosis, predict prognosis and follow disease progression and treatment response. Previously, conventional radiography was the principal method used to evaluate and follow bone damage in patients with inflammatory arthritis. More recently the use of magnetic resonance imaging and ultrasonography has gained wider acceptance and popularity due to the ability of these multiplanar techniques to image both bone changes and soft tissue abnormalities, including synovitis. This chapter discusses the current imaging modalities used in the evaluation of patients with early arthritis, as well as the use of imaging in establishing the extent of disease, in prognosis and in monitoring disease course. Current data on imaging of patients with early arthritis due to rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis is reviewed.

Doppler sonography in rheumatology

The importance of ultrasonography in rheumatology has increased dramatically within the last few years both with regard to clinical practice and to research. High-resolution colour Doppler ultrasound equipment is, to date, widely available. Colour and power Doppler studies of intra-articular and peritendinous blood flow allow an estimation of the inflammatory activity and aid in distinguishing anatomical structures. Contrast agent increases the ability of ultrasonography to detect even minor perfusion. These findings have a practical clinical impact on the management of inflammatory rheumatic diseases. The resolution of ultrasonography is superior to that of magnetic resonance imaging (MRI) and computed tomography (CT) with regard to superficial anatomical structures. Furthermore, ultrasonography can depict the artery wall in contrast to angiography. In temporal arteritis and Takayasu's arteritis, ultrasonography depicts characteristic, homogenous wall thickening, stenoses and acute occlusions. These pathologies resolve quickly with treatment in the temporal arteries and much more slowly in larger arteries.

Serum vascular markers and vascular imaging in assessment of rheumatoid arthritis disease activity and response to therapy

Vascular pathology, in the form of angiogenesis, is important in the perpetuation of rheumatoid arthritis (RA) and, in the form of endothelial dysfunction, contributes to associated cardiovascular co-morbidity. Emerging evidence suggests that TNFalpha blockade may modify vascular pathology in RA. Serum concentrations of vascular endothelial growth factor (VEGF), a potent endothelial cell-specific growth factor that is up-regulated by pro-inflammatory cytokines and by hypoxia, are elevated in RA and correlate with disease activity. Serum levels of VEGF at first presentation in RA predict radiographic progression of the disease over the subsequent year. Power Doppler ultrasonography is a sensitive method for demonstrating the presence of blood flow in small vessels and the vascular signal correlates with histopathological quantification of the vascular density of synovial tissue. Recent data indicate that high-frequency ultrasound and power Doppler are sensitive tools for evaluation of disease activity and assessment of response to therapy. Power Doppler imaging may also have the potential to predict those patients most at risk of accelerated joint destruction. However, much work has yet to be done to standardize the use of these imaging technologies.

Interobserver reliability of rheumatologists performing musculoskeletal ultrasonography: results from a EULAR "Train the trainers" course

OBJECTIVE

To evaluate the interobserver reliability among 14 experts in musculoskeletal ultrasonography (US) and to determine the overall agreement about the US results compared with magnetic resonance imaging (MRI), which served as the imaging "gold standard".

METHODS

The clinically dominant joint regions (shoulder, knee, ankle/toe, wrist/finger) of four patients with inflammatory rheumatic diseases were ultrasonographically examined by 14 experts. US results were compared with MRI. Overall agreements, sensitivities, specificities, and interobserver reliabilities were assessed.

RESULTS

Taking an agreement in US examination of 10 out of 14 experts into account, the overall kappa for all examined joints was 0.76. Calculations for each joint region showed high kappa values for the knee (1), moderate values for the shoulder (0.76) and hand/finger (0.59), and low agreement for ankle/toe joints (0.28). kappa Values for bone lesions, bursitis, and tendon tears were high (kappa = 1). Relatively good agreement for most US findings, compared with MRI, was found for the shoulder (overall agreement 81%, sensitivity 76%, specificity 89%) and knee joint (overall agreement 88%, sensitivity 91%, specificity 88%). Sensitivities were lower for wrist/finger (overall agreement 73%, sensitivity 66%, specificity 88%) and ankle/toe joints (overall agreement 82%, sensitivity 61%, specificity 92%).

CONCLUSION

Interobserver reliabilities, sensitivities, and specificities in comparison with MRI were moderate to good. Further standardisation of US scanning techniques and definitions of different pathological US lesions are necessary to increase the interobserver agreement in musculoskeletal US.

Rheumatoid and psoriatic knee synovitis: clinical, grey scale, and power Doppler ultrasound assessment of the response to etanercept

OBJECTIVE

To determine the effect of tumour necrosis factor alpha (TNFalpha) blockade with etanercept in refractory knee joint synovitis (KJS) in rheumatoid and psoriatic arthritis, by local and systemic disease activity assessment and combined grey scale and power Doppler ultrasonographic monitoring.

METHODS

27 knees affected by rheumatoid KJS (n = 12) and psoriatic KJS (n = 8) were assessed before receiving treatment and at 3 and 12 months' follow up. Time dependent clinical changes in disease activity were monitored by C reactive protein, erythrocyte sedimentation rate (ESR), global health status (GHS), and Ritchie (RAI) and knee joint articular (KJAI) indices; synovial changes were monitored by ultrasonographic and power Doppler indices for grey scale synovial thickening and for distinct intrasynovial vessel power Doppler flow configurations (fluid/synovium interface (F/SI-PD) and pannus/cartilage interface (P/CI-PD)). Interobserver and intraobserver variability of grey scale and power Doppler ultrasonographic was evaluated. Response to treatment was assessed by analysis of variance for repeated measures on clinical and ultrasonographic variables.

RESULTS

Rapid (3 months) reduction in F/SI-PD flow (p<0.001), parallel to reductions of C reactive protein (p<0.05), ESR (p<0.001), KJAI (p<0.002), RAI, and GHS (p<0.001), was sustained at 12 months when it was accompanied by reduction in both synovial thickening and P/CI-PD flow (p<0.001). No differences (ANOVA) were noted at baseline or at 12 months in clinical and ultrasonographic variables between either the rheumatoid or the psoriatic KJS groups.

CONCLUSION

Grey scale and power Doppler ultrasonography are reliable measures of long term change in rheumatoid and psoriatic KJS disease activity in response to anti-TNFalpha treatment with etanercept.

Performance characteristics of ultrasound of the knee in a general radiological setting

Ultrasound of the musculoskeletal system is an attractive imaging modality due to the lack of ionising radiation, cost and ease of availability. A role has been established in the shoulder and pediatric hip but not in the knee. Ultrasound studies of the knee performed at six general radiological practices without established musculoskeletal expertise were compared with clinical examination in 56 patients. Final diagnoses were established by arthroscopy and/or MRI. The sensitivity and specificity for detection of superficial lesions in the knee were 88 and 41% for clinical examination and 32 and 59% for ultrasound. For deep lesions sensitivity and specificity were 61 and 64% for clinical examination and 13 and 100% for ultrasound. Ultrasound studies of the knee in a general radiological practice do not offer significant information above clinical examination.

Comparison of ultrasonographic assessment of synovitis and joint vascularity with radiographic evaluation in a randomized, placebo-controlled study of infliximab therapy in early rheumatoid arthritis

OBJECTIVE

To investigate sensitive ultrasonographic imaging methods for detection of synovial thickness and vascularity to discriminate between patients with early rheumatoid arthritis (RA) receiving infliximab + methotrexate (MTX) versus placebo + MTX over 18 weeks, and to compare the relationship between synovial thickening and vascularity at baseline and radiologic damage to joints of the hands and feet at 54 weeks.

METHODS

Patients with early RA (duration <3 years) receiving stable dosages of MTX were randomly assigned to receive blinded infusions of 5 mg/kg infliximab (n = 12) or placebo (n = 12) at weeks 0, 2, 6, and then every 8 weeks until week 46. At baseline and week 18, clinical assessments were performed, and metacarpophalangeal joints were assessed by high-frequency ultrasonography and power Doppler ultrasonography measurements. Radiographs of the hands and feet taken at baseline and at 54 weeks were evaluated using the van der Heijde modification of the Sharp method (vdH-Sharp score).

RESULTS

Using changes in the total vdH-Sharp score over 54 weeks and changes in synovial thickening and joint vascularity at 18 weeks, we were able to distinguish those patients receiving infusions of infliximab + MTX from those receiving placebo + MTX. Sonographic measurements of synovial thickening and vascularity at baseline in the placebo + MTX group demonstrated clear relationships with the magnitude of radiologic joint damage at week 54. Infliximab + MTX treatment abolished these relationships.

CONCLUSION

The delay or reversal of inflammatory and joint-destructive mechanisms in patients with early RA was already apparent following 18 weeks of treatment with infliximab + MTX and was reflected in radiologic changes at 54 weeks.

Musculoskeletal ultrasound--a state of the art review in rheumatology. Part 1: Current controversies and issues in the development of musculoskeletal ultrasound in rheumatology

As we begin the 21st century, musculoskeletal ultrasound (MSUS) is routinely used by an increasing number of rheumatologists throughout Europe and there is a growing interest in the application of MSUS in rheumatological practice in the UK. MSUS allows high-resolution, real-time imaging of articular and periarticular structures and has the advantages of being non-radioactive, inexpensive, portable, highly acceptable to patients and repeatable. There are a number of critical issues that need to be addressed in order to develop the role of MSUS within rheumatology. These include issues of equipment costs, training and certification and the relationship of rheumatologists and radiologists in advancing the field of MSUS. Rheumatologists must demonstrate the relevance of MSUS in their clinical practice through high-quality research. Emerging technologies such as power Doppler and 3D imaging will further improve imaging capabilities and the range of clinical applications of MSUS systems. This paper reviews how MSUS in rheumatology has evolved and the controversies and issues that rheumatologists must now address in developing MSUS as an indispensable, everyday clinical tool.

Ultrasonography in rheumatoid arthritis: a very promising method still needing more validation

PURPOSE OF REVIEW

Through recent technological advances, ultrasonography allows high-resolution visualization of inflammatory and destructive changes in the small superficial joints of hands and feet, and ultrasonography is increasingly used by rheumatologists for assessment of rheumatoid arthritis patients. It is, therefore, highly relevant to consider the validity of ultrasonographic measures of rheumatoid joint inflammation and damage.

RECENT FINDINGS

Organized by type of validity, data on ultrasonography in rheumatoid arthritis are reviewed. Encouraging reports of high agreement of ultrasonographic findings between observers, with MRI and, in knee and hip joints, histopathologic assessments were recently published. New quantitative and semiquantitative evaluation methods have been suggested, and the first systematic follow-up studies suggest an ability of ultrasonography to monitor joint inflammation and damage. However, a number of essential issues are still largely unexplored, including interscanner variability, sensitivity to change, prognostic value, and value in the diagnosis of rheumatoid arthritis. Suggested areas of priority in research and development of ultrasonography in rheumatoid arthritis are outlined.

SUMMARY

Ultrasonography is a very promising method in the assessment of rheumatoid arthritis joints, but still needs more validation before it can take up its expected role on a scientific basis as an important tool for diagnosis, monitoring, and prognostication of patients with rheumatoid arthritis and suspected rheumatoid arthritis.

Sonographic study of calcaneal entheses in erosive osteoarthritis, nodal osteoarthritis, rheumatoid arthritis and psoriatic arthritis

OBJECTIVE

To establish by ultrasonography (US) the frequency of calcaneal entheses involvement in erosive osteoarthritis (EOA), nodal osteoarthritis (NOA), RA and PsA, and to compare these results in order to aid clinicians in the differential diagnosis among these diseases. A comparison between US results and radiography was also made.

METHODS

The heels of 56 consecutive outpatients with EOA, 209 with NOA, 158 with RA and 125 with PsA were studied by US and radiography. A control group of 50 subjects was examined by US.

RESULTS

US showed no significant difference in inferior calcaneal enthesophytosis among the four diseases. The frequency of posterioinferior enthesophytosis was lower in RA (34%) in comparison with the other diseases (57% in EOA, 47% in NOA, 49% in PsA). Achilles enthesitis was found in 8% of PsA and in 2% of RA. Retrocalcaneal bursitis was found in 18% of RA and in 6% of PsA. Posterior erosions were present in 12% of RA and 5% of PsA. Inferior erosions were present in 6% of RA and in 1% of PsA. Plantar fasciitis was found in 26% of RA, in 37% of PsA, and in 15% of NOA and 12% of EOA. Subcalcaneal panniculitis was observed in 10% of RA and in 1% of PsA. In the control group, only posterioinferior and inferior enthesophytosis (22% and 18% respectively) were found. Kappa statistics show excellent agreement between US and radiography in detecting posterioinferior (kappa = 0.89) and inferior enthesophytosis (kappa = 0.83), and entheseal erosions (kappa = 0.86).

CONCLUSIONS

The calcaneal lesions that could be found in EOA are similar to those observed in NOA. The frequency of calcaneal enthesophytosis is similar in EOA, NOA, and PsA, but inflammatory lesions of calcaneal entheses and of the adjacent bursae are more frequent in RA and in PsA. In terms of heel involvement, EOA seems to be similar to NOA. US shows an excellent concordance with radiography in detecting entheseal cortical bone abnormalities.

New developments in imaging in rheumatoid arthritis

Despite the advances made in medical imaging over the past 3 decades and the central role that magnetic resonance imaging and other sophisticated technologies now play in routine clinical practice, patients with rheumatoid arthritis have benefited relatively little from these advances thus far. Over the past few years, however, evidence has accumulated to show that magnetic resonance imaging and ultrasonography can identify joint damage in patients with rheumatoid arthritis earlier and more sensitively than other techniques can, and that these techniques can directly visualize and monitor changes in synovium and bone that precede actual bone erosion. Much of this development is being driven by the pharmaceutical and biotechnology industries as they search for novel therapies to combat this disease. Accordingly, the imaging tools that ultimately will be used to direct patients to specific therapies and then to monitor treatment effectiveness and safety are currently being refined and validated in rigorous multicenter and multinational clinical trials aimed at gaining regulatory approval of these new therapies. As these therapies become available for clinical use, we can anticipate increased demand for expertise and experience in evaluating disease progression and treatment response, and to the emergence of magnetic resonance imaging systems specifically adapted for this application. The following discussion reviews the current status of this development, and notable advances that have been reported in the literature in the past year.

The value of sensitive imaging modalities in rheumatoid arthritis

X-ray evaluation of rheumatoid joints is relatively inexpensive, is widely available and has standardised methods for interpretation. It also has limitations, including the inability to reliably determine structural change in less than 6-12 months, the need for experienced readers to interpret images and the limited acceptance of this technique in routine clinical practice. High-frequency ultrasound, with or without power Doppler, and magnetic resonance imaging of rheumatoid joints permit an increasingly refined analysis of anatomic detail. However, further research using these sensitive imaging technologies is required to delineate pathophysiological correlates of imaging abnormalities and to standardise methods for assessment.

In vivo imaging approaches in animal models of rheumatoid arthritis

The interaction of activated leukocytes with the rheumatoid synovial environment is a key process in arthritis. Understanding this process will play an important role in designing effective treatments. In vivo imaging approaches combined with molecular genetics in animal models provide important tools to address these issues. The present review will focus on approaches to in vivo imaging, with particular attention to approaches that are proving useful for, or have promise for, research on animal models of rheumatoid arthritis. These approaches will probably shed light on the specific local mechanisms involved in chronic inflammation and provide real time monitoring approaches to follow cellular and molecular events related to disease development.