Ultrasound detection of bone erosions in rheumatoid arthritis: a comparison to routine radiographs of the hands and feet

Purpose To determine if ultrasound (US) of selected joints in the hands and feet can detect more erosions than radiography and establish the presence of erosive disease in patients with rheumatoid arthritis (RA).Methods Eighty joints in ten patients with RA and 40 joints in five healthy control subjects, who were age, gender and ethnicity-matched to the patients with arthritis, were prospectively studied with radiographs and sonography. Conventional radiographs of the hands and feet were obtained. US examinations of the 2nd and 5th metacarpal-phalangeal (MCP) joints of the hands, and the 1st and 5th metatarsal-phalangeal (MTP) joints of the feet were performed. Radiographs and US exams were independently graded for the presence of erosions.Results None of the control subjects had erosions. US detected erosions in 17/80, and radiographs detected erosions in 6/80 joints assessed with both modalities. US detected all erosions seen by radiographs in these selected joints. Erosive disease was present in the radiographs of seven of ten RA patients. US established erosive disease in eight of ten RA patients. US determined erosive disease in two of the three patients without radiographic erosions.Conclusions US of the MTP and MCP joints in RA can detect erosions not seen with radiography and may be complementary to radiography in establishing the presence of erosive disease in early RA.     

Rheumatoid hand joint synovitis: gray-scale and power Doppler US quantifications following anti-tumor necrosis factor-alpha treatment: pilot study

PURPOSE: To evaluate by using B-mode and power Doppler ultrasonography (US) and clinical assessment the response of hand joint synovitis in patients with active rheumatoid arthritis (RA) to treatment with the anti-tumor necrosis factor-alpha agent infliximab. MATERIALS AND METHODS: Wrists, metacarpophalangeal (MCP) joints, and proximal interphalangeal (PIP) joints in 11 patients with active RA were assessed before and 6 weeks after three infliximab infusions. US assessment was performed at a single site in the MCP and PIP joints and at two sites (radiocarpal and intercarpal) in the wrists. Twenty measurements were performed in the wrists; 110 measurements, in the MCP joints; and 103 measurements, in the PIP joints. Two wrists and seven PIP joints were excluded owing to complete joint destruction. US parameters (synovial thickness, number of US-positive joints [ie, with synovial thickness > or = 1 mm], cumulative synovial thickness index, and presence of Doppler signal) and clinical parameters (swollen joint count) were independently assessed and compared with baseline values by using the McNemar chi2 and paired Student t tests. RESULTS: After infliximab treatment, there was a significant decrease in the mean numbers of swollen and US-positive joints and in the cumulative synovial thickness (P <.05). The mean synovial thickness decreased in all joints swollen at baseline and in the MCP and PIP joints not swollen at baseline (P <.01). Change from baseline cumulative synovial thickness correlated significantly with change in disease activity score (r = 0.69, P <.05). The number of positive Doppler US signals decreased significantly (in 13 US-positive joints at baseline, in five after treatment; P <.05). CONCLUSION: US is a feasible imaging modality for measurement of the response of RA small-joint synovitis to therapy.     

Quantification of synovial and erosive changes in rheumatoid arthritis with ultrasound—Revisited

Synovitis is a predictive factor of irreversible changes in the joints, tendons, and ligaments in patients with rheumatoid arthritis (RA). Therefore, the early demonstration of reversible, pre-erosive inflammatory features to diagnose RA, the monitoring of disease activity, and the response to therapy are of great importance. Technical developments in ultrasound now allow the quantification of synovitis and erosions, and enable the assessment and follow-up of disease activity. However, both the subjective and objective quantification techniques are associated with different problems. This review article highlights the advantages and disadvantages of sonographic quantification, and revisits the somewhat controversial positions apparent in the current literature. Familiarity with the imaging findings and the scoring systems used to characterize erosive changes are prerequisites for considerably improving the detection and monitoring of synovitis and erosions. The role of ultrasound in the diagnostic approach to RA, particularly in the quantification of synovial and erosive changes, will be explored and the current literature will be reviewed.     

Contrast enhanced gray-scale sonography in assessment of joint vascularity in rheumatoid arthritis: results from the IACUS study group

The purpose of this study way to assess the value of contrast enhanced gray-scale ultrasound (CEUS) in detection of vascularity in joints of patients with rheumatoid arthritis (RA) in a multicenter study of the International Arthritis Contrast Ultrasound (IACUS) study group. We assessed 113 joints in 113 patients (44 men, 69 women; mean age 51±14 years) with clinical diagnosis of RA. Gray-scale ultrasound (US), power Doppler US (PDUS) and CEUS, using a low mechanical index US technique, was performed. CEUS was done by bolus administration of the contrast agent SonoVue (Bracco, Milan, Italy) with a dosage of 4.8-ml SonoVue flushed with 10 ml saline. Detection of joint vascularity was performed for differentiation of active synovitis from inactive intra-articular thickening (synovitis/effusion). With the use of US and PDUS, active synovitis could be differentiated from inactive intra-articular thickening in 68/113 joints (60.1%), whereas CEUS enabled differentiation in 110/113 (97.3%) joints (p<0.0001). Thickness measurement of active synovitis was significantly improved after contrast administration (p=0.008). In conclusion, CEUS improves the differentiation of active synovitis from inactive intra-articular thickening. Since CEUS has shown an ability to improve assessment of vascularized synovial proliferation in RA affected joints, this technique may have further potential in monitoring therapy.     

Imaging of bone erosion in rheumatoid arthritis

Rheumatoid arthritis (RA) is the most common type of inflammatory arthritis, with a prevalence of 1% in the United States. Recently introduced disease-modifying antirheumatic drugs have been extremely successful in preventing irreversible joint damage, particularly if initiated early. Accordingly, accurate and early diagnosis of RA has become imperative. This shift places increased demands on imaging to identify even the slightest traces of erosive joint damage and predict future structural and functional deterioration. Unfortunately, conventional radiography has been shown to be insensitive for bone erosions, particularly in early stages of the disease. Computed tomography (CT) is rarely used, but its tomographic perspective offers advantages over projectional radiography. Ultrasound (US) detects more erosions than radiography does and also can evaluate synovitis. Scintigraphy also can detect inflammation and bone turnover at sites of active erosion. It lacks spatial resolution but offers greater anatomical coverage, making whole-body assessments possible. Of all imaging modalities, however, magnetic resonance imaging (MRI) shows the greatest sensitivity for detecting and monitoring bone erosions and also can detect and follow pre-erosive features of RA, such as synovitis, bone marrow edema or osteitis, and tendinous and ligamentous abnormalities. In this article, we review the appearance of bone erosions on conventional radiography and alternative imaging modalities including MRI, CT, US, and scintigraphy. We also review alternative acquisition techniques for MRI in RA and discuss the utility of fat suppression and contrast enhancement.     

Quantification of synovitis in the cranio-cervical region: Dynamic contrast enhanced and diffusion weighted magnetic resonance imaging in early rheumatoid arthritis-A feasibility follow up study

Objective

To test the feasibility of dynamic contrast enhanced (DCEI) and diffusion weighted (DWI) magnetic resonance imaging (MRI) for quantifying synovitis of the cranio-cervical (C-C) region in patients with early rheumatoid arthritis (RA) and neck pain at the beginning and at a six month follow up.

Methods

27 patients with duration of RA of less than 24 months and neck pain were studied with standard qualitative MRI evaluation and two quantitative MRI methods (DCEI and DWI) at the level of atlantoaxial joints. Rate of early enhancement (REE), enhancement gradient (Genh) and apparent diffusion coefficient (ADC) were extracted from DCEI and DWI data. MRI was coupled with clinical assessment and radiographic imaging.

Results

Using standard qualitative MRI evaluation, unequivocal active synovitis (grade 2 or 3 contrast enhancement) was proved in 16 (59%) patients at baseline and 14 (54%) at follow up. DCEI and DWI measurements confirmed active synovitis in 25 (93%) patients at baseline and 24 (92%) at follow up. Average REE, Genh and ADC values decreased during follow up, however the difference was not statistically significant (p > 0.05). Both qualitative and quantitative MRI methods confirmed active inflammatory disease in the C-C region following therapy although all clinical criteria showed signs of improvement of the peripheral disease.

Conclusions

The study proved the feasibility of DCEI and DWI MRI for quantifying synovitis of the C-C region in patients with early RA and neck pain. Both techniques can be used as additional method for evaluation of synovitis of the C-C region in RA.     

Utility of combined high-resolution bone SPECT and MRI for the identification of rheumatoid arthritis patients with high-risk for erosive progression

Objectives

To evaluate the utility of sequentially acquired, post hoc fused, magnetic resonance imaging (MRI) and multi-pinhole single photon emission computed tomography (MPH-SPECT) with technetium-99m-labeled disphosphonates (Tc99m-DPD) for the identification of finger joints with later erosive progression in early rheumatoid arthritis (ERA) patients.

Methods

Ten consecutive ERA patients prospectively underwent MPH-SPECT and MRI of metacarpophalangeal (MCP) joints prior to and after 6 months methotrexate therapy. Tc99m-DPD uptake was measured at proximal and distal MCP sites using regional analysis. The course of joint pathologies was scored according to the Rheumatoid Arthritis MRI Score (RAMRIS) criteria.

Results

The frequency of increased Tc99m-DPD uptake, synovitis and bone marrow edemadecreased under MTX therapy; but the number of bone erosions increased. Joints with progressive and new erosions on follow-up had a higher baseline Tc99m-DPD uptake (2.64 ± 1.23 vs. 1.43 ± 0.91) (p = 0.02).

Conclusions

Joints with erosive progression are characterized by an early increased Tc99m-DPD uptake, even in absence of MRI bone pathologies. Tc99m-DPD MPH-SPECT might thus be of additional value to morphological MRI for the identification of RA patients with a high risk for erosive progression.     

Familial early onset sarcoidosis with bone cysts and erosions

Early onset sarcoidosis is a granulomatous disease which is characterized by synovitis, polyarthritis, skin and eye involvement. We report the skeletal features of one patient with a family history and clinical symptoms suggestive of early onset sarcoidosis (EOS) which was confirmed by skin biopsy. Radiographs reveal postarthritic deformities of the MCP joints, contractures, a coarsened trabecular pattern at the PIP joints and small bone cysts resembling osteitis cystoides multiplex. Similar lesions were described in radiographs of the older sister and an uncle of our patient. This is the first report demonstrating bone cysts and erosions which could be a diagnostic feature in this rare disease and may help to differentiate other rheumatoid disorders.     

Prediction of erosion progression using ultrasound in established rheumatoid arthritis: a 2-year follow-up study

Objectives  This study aimed to determine whether a range of single-time-point ultrasound (US) measures of synovial disease and serologic characteristics were able to predict progression of US-defined erosive disease in patients with established rheumatoid arthritis (RA). Materials and methods  Forty patients were studied prospectively. At baseline, subjective US measures of bone damage and synovial disease, including grayscale and power Doppler (PD) scores pre- and post-Sonovue contrast, were obtained from one proximal inter-phalangeal or metacarpo-phalangeal joint per patient. After a minimum of 2 years, the same joints were scanned to obtain a new US erosion score. Results  Follow-up US erosion scores were obtained in 25 joints. Progressive US determined that bone damage occurred in 12/25 joints, including four of eight treated with anti-tumor necrosis factor therapy. Baseline erosion scores were significantly higher in joints that did not show progressive bone damage in the entire cohort (p = 0.05, n = 25) and a subgroup treated with disease-modifying anti-rheumatic drugs (p = 0.015, n = 17). There were no other significant differences in baseline US or serologic scores between joints that developed progressive damage and those that did not. Conclusions  The majority of single-time-point US measures of synovial disease were not able to identify metacarpo-phalangeal or inter-phalangeal joint destined to develop progressive US-determined bone damage in patients with established RA. This may reflect the use of single-time-point measures, insensitivity of the US erosion score, and the long duration of RA disease in this study.     

MRI quantification of rheumatoid arthritis: Current knowledge and future perspectives

The international consensus on treatment of rheumatoid arthritis (RA) involves early initiation of disease modifying anti-rheumatic drugs (DMARDs) for which a reliable identification of early disease is mandatory. Conventional radiography of the joints is considered the standard method for detecting and quantifying joint damage in RA. However, radiographs only show late disease manifestations as joint space narrowing and bone erosions, whereas it cannot detect synovitis and bone marrow oedema, i.e., inflammation in the synovium or the bone, which may be visualized by magnetic resonance imaging (MRI) months to years before erosions develop. Furthermore, MRI allows earlier visualization of bone erosions than radiography. In order to allow early treatment initiation and optimal guidance of the therapeutic strategy, there is a need for methods which are capable of early detection of inflammatory joint changes. In this review, we will discuss available data, advantages, limitations and potential future of MRI in RA.     

MRI of the wrist and finger joints in inflammatory joint diseases at 1-year interval: MRI features to predict bone erosions

The aim of this study was to assess the ability of MRI determined synovial volumes and bone marrow oedema to predict progressions in bone erosions after 1 year in patients with different types of inflammatory joint diseases. Eighty-four patients underwent MRI, laboratory and clinical examination at baseline and 1 year later. Magnetic resonance imaging of the wrist and finger joints was performed in 22 patients with rheumatoid arthritis less than 3 years (group 1) who fulfilled the American College of Rheumatology (ACR) criteria for rheumatoid arthritis, 18 patients with reactive arthritis or psoriatic arthritis (group 2), 22 patients with more than 3 years duration of rheumatoid arthritis, who fulfilled the ACR criteria for rheumatoid arthritis (group 3), and 20 patients with arthralgia (group 4). The volume of the synovial membrane was outlined manually before and after gadodiamide injection on the T1-weighted sequences in the finger joints. Bones with marrow oedema were summed up in the wrist and fingers on short-tau inversion recovery sequences. These MRI features was compared with the number of bone erosions 1 year later. The MR images were scored independently under masked conditions. The synovial volumes in the finger joints assessed on pre-contrast images was highly predictive of bone erosions 1 year later in patients with rheumatoid arthritis (groups 1 and 3). The strongest individual predictor of bone erosions at 1-year follow-up was bone marrow oedema, if present at the wrist at baseline. Bone erosions on baseline MRI were in few cases reversible at follow-up MRI. The total synovial volume in the finger joints, and the presence of bone oedema in the wrist bones, seems to be predictive for the number of bone erosions 1 year later and may be used in screening. The importance of very early bone changes on MRI and the importance of the reversibility of these findings remain to be clarified.     

Semi-quantitative analysis of rheumatoid finger joint synovitis using power Doppler ultrasonography: when to perform follow-up study after treatment consisting mainly of antitumor necrosis factor alpha agent

Purpose

To determine the timing for follow-up study of power Doppler ultrasonography (PDUS) by evaluating the response of finger joint synovitis in patients with rheumatoid arthritis (RA) to treatment including infliximab, an antitumor necrosis factor alpha agent.

Methods and materials

Bilateral second/third metacarpo-phalangeal (MCP) joints and second proximal inter-phalangeal (PIP) joints (total of six joints) in 21 patients (18 women and three men; median age 53 years) with chronic active RA were assessed by PDUS before and after 2 weeks, 6 weeks, 14 weeks, 30 weeks, 38 weeks, 46 weeks, and 54 weeks of infliximab infusion. Pulse Doppler settings were standardized for each patient and optimized for the detection of synovial blood flow by adjustment of color gain, pulse repetition, and flow optimization. Power Doppler signal was graded for each joint [joint grade for power Doppler (JGPD) signals], and the sum of the grades of six joints was defined as the PDUS index [joint index for power Doppler signals (JIPD)] at each visit. PDUS and clinical parameters [28-joint disease activity score (DAS28), health assessment questionnaire, and C-reactive protein (CRP) level] were independently assessed and compared with baseline values. The American College of Rheumatology (ACR) core set responders and non-responders at week 54 were compared for clinical parameters and PDUS index at each visit.

Results

Fourteen patients completed the planned treatment for 1 year, while six patients dropped out for various reasons and one died suddenly. PDUS was performed a total of 146 times on 467 joints. DAS28 was assessed 127 times. Both DAS28 and JIPD had decreased at the follow-up. Comparative analysis between DAS28 and PDUS was available 125 times. The transverse correlation between the PDUS index and DAS28 was not significant throughout the follow-up period. When responders and non-responders were discriminated at week 54, a logistic regression model for the binary endpoint of responder vs non-responder, with PDUS index as explanatory variable at time point 0, and follow-up revealed statistical significance from week 38 and on.

Conclusion

PDUS reflected infliximab’s effect on pannus vascular signals; this effect was observed as early as 2 weeks after treatment had begun. Also, the responders to treatment at 54 weeks tended to have fewer JIPD than non-responders in the follow-up period. PDUS may be performed at week 38 or later to foresee the response to the treatment at week 54.     

Quantification of synovitis in Rheumatoid Arthritis: Do we really need quantitative measurement of contrast-enhanced ultrasound?

Objective

The quantification of synovitis is of great significance for adequate therapy management and follow-up in patients with Rheumatoid Arthritis (RA). The purpose of this study was to validate a semi-quantitative Power Doppler (PD) scoring system by comparing the PD scores to the objective measurement of the synovial inflammation using dynamic contrast-enhanced Pulse-Inversion Harmonic Imaging (PIHI).

Materials and methods

In 27 patients with RA, two radiologists performed semi-quantitative scoring of a PD examination, using a four-point scale from 0 to 3, in the metacarpophalangeal joints, proximal interphalangeal joints, and the wrists. The scores were compared to the area under the time-echo intensity curves obtained by contrast-enhanced PIHI examination. The interobserver agreement for PD scoring was evaluated using the Cohen's kappa test.

Results

Preliminary results showed that the area under the curve of dynamic measurements of PIHI tended to correlate with PD scores. The interobserver agreement for PD scoring was good (κ = 0.768).

Discussion

Based on comparisons with dynamic contrast-enhanced PIHI, semi-quantitative PD scoring might meet the criteria for a reliable, reproducible, and practical scoring system. Although further studies that would include a larger study population are required, our preliminary results show that PIHI may not provide a real benefit for quantification of synovitis in day-to-day practice.     

High-resolution MRI of the wrist and finger joints in patients with rheumatoid arthritis: comparison of 1.5 Tesla and 3.0 Tesla

The goal of this study was to compare magnetic resonance (MR) image quality at different field strengths for evaluating lesions in wrist and finger joints of patients with rheumatoid arthritis (RA) in order to determine whether the higher field strength provides diagnostic gain. The hand mainly affected in 17 RA patients was examined at 1.5 Tesla (T) and 3.0 T with comparable MR imaging (MRI) protocols. MR images were reviewed twice by two experienced radiologists using the Rheumatoid Arthritis MRI Scoring System (RAMRIS) of the OMERACT (Outcome Measures in Rheumatoid Arthritis Clinical Trials) group. Image quality was rated on a five-point scale using Friedmann’s test and Kendall’s W-test for statistical analysis. Image comparison revealed better image quality at higher field strength. Image quality of T1-weighted images was rated 14–22% better at 3.0 T compared with 1.5 T by both readers. Moreover, the rating for the T2-weighted-images acquired at 3.0 T was one point better in the five-point scale used. Inter-reader correlation for image quality, bone erosions/defects, edema and synovitis ranged between 0.6 and 0.9 at 3.0 T and between 0.6 and 0.8 at 1.5 T. Intra-reader correlation for these parameters was high at 0.8–1.0. MRI image quality of RA hands is superior at 3.0 T, while an acceptable image quality is achieved at 1.5 T, which improves the evaluation of extent of bone edema, synovitis and identification of small bone erosions.     

Power Doppler ultrasonography for assessment of rheumatoid synovitis: comparison with dynamic magnetic resonance imaging

PurposeThe aim of this study was to compare the effectiveness of power Doppler ultrasonography (PDUS) with that of dynamic magnetic resonance imaging (MRI) for detecting active synovitis in the hands of rheumatoid arthritis (RA) patients.Materials and MethodsPDUS and dynamic MRI were performed for a total of 220 finger joints with active RA. Each synovial blood flow by PDUS and dynamic MRI was measured and categorized into four grades.ResultsTaking dynamic MRI as a reference, PDUS showed a sensitivity of 94%, a specificity of 95%, and an accuracy of 95%.ConclusionPDUS is useful for detection of active synovitis in the overall-grade RA patients.     

Advanced imaging in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic and progressive inflammatory disorder primarily affecting the synovium. We now recognise that conventional radiographic images show changes of rhuematoid arthritis late after irreversible joint damage has occured. With the advent of powerful disease-modifying drugs there is a need for early demonstration of rheumatoid arthritis and to monitor progress of the disease and response to therapy. Advanced imaging techniques such as ultrasound and MRI have focussed on the demonstration and quanitification of synovitis and erosions and allow early diagnosis of RA. The technology to quantify synovitis and erosions is developing rapidly and now allows change in disease activity to be assessed. However, problems undoubtedly exist in quantification techniques and this review serves to highlight them. Much of the literature on advanced imaging in RA appears in rheumatological journals and may not be familiar to radiologists. This review article aims to increase the awareness of radiologists to this field and to encourage them to participate and contribute to the ongoing development of these modalities. Without this collaboration it is unlikely that these modalities will reach their full potential in the field of rheumatological imaging. This review is in two parts. This first part addresses synovitis imaging. The second part will look at advanced imaging of erosions in RA. Part 1 of this article (Synovitis) can be found at: . In our previous article we described issues surrounding the advanced imaging of synovitis. This article addresses erosions in a similar manner.     

Assessment of disease activity in rheumatoid arthritis with (18)F-FDG PET.

The aim of this study was to assess synovitis by (18)F-FDG PET in an individual joint analysis and in a global analysis of rheumatoid arthritis (RA) disease activity and to compare (18)F-FDG PET parameters with clinical, biologic, and sonographic (US) rheumatoid parameters. METHODS: Three hundred fifty-six joints were assessed in 21 patients with active RA: the knees in all subjects and either wrists as well as metacarpophalangeal and proximal interphalangeal joints in 13 patients, or ankles and the first metatarsophalangeal joints in the remaining 8 patients. PET analysis consisted of a visual identification of (18)F-FDG uptake in the synovium and measurements of standardized uptake values (SUVs). Independent assessors performed the clinical and US examinations. RESULTS: PET positivity was found in 63% of joints, whereas 75%, 79%, and 56% were positive for swelling, tenderness, and US analysis, respectively. Both the rate of PET-positive joints and the SUV increased with the number of positive parameters present (swelling, tenderness, US positivity) and with the synovial thickness. The mean SUV was significantly higher in joints where a power Doppler signal was found. In a global PET analysis, the number of PET-positive joints and the cumulative SUV were significantly correlated with the swollen and tender joint counts, the patient and physician global assessments, the erythrocyte sedimentation rate and C-reactive protein serum levels, the disease activity score and the simplified disease activity index, the number of US-positive joints, and the cumulative synovial thickness. CONCLUSION: (18)F-FDG PET is a unique imaging technique that can assess the metabolic activity of synovitis and measure the disease activity in RA.     

Contrast-enhanced power Doppler ultrasonography of the metacarpophalangeal joints in rheumatoid arthritis

The aim of this study was to examine, with dynamic contrast-enhanced MRI as the reference, if contrast-enhanced power Doppler ultrasonography (CE PDUS) of rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints provides additional information for evaluation of synovial inflammation compared with PDUS. One MCP joint in each of 15 RA patients and 3 healthy control persons were examined with PDUS before and after intravenous bolus Levovist contrast injection. Corresponding rates of early synovial enhancement (RESE), previously shown to be closely related to histopathological synovitis, were calculated from dynamic contrast-enhanced MR images obtained the same day. Prior to ultrasonography, the joint was evaluated clinically. Levovist increased the flow signal in 7 of 9 joints with pre-contrast flow-signal and in 0 of 9 without pre-contrast signal. No healthy controls showed CE PDUS signal. The results of CE PDUS and dynamic MRI were closely related: RESE in joints with CE PDUS signal was significantly higher than in joints without CE PDUS signal (Mann-Whitney test, p<0.001). Among the patients with pre-contrast PDUS signal no statistically significant difference in RESE values was found between joints with and without post-contrast flow-signal increase. No correlation was found between clinical examination and CE PDUS. Based on comparisons with dynamic contrast-enhanced MRI, PDUS appears to be reliable for assessment of synovitis in RA MCP joints. Intravenous contrast injection may provide additional information in selected cases but did not in the present study increase the sensitivity of the method. Electronic Publication     

Advanced imaging in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic and progressive inflammatory disorder primarily affecting the synovium. We now recognise that conventional radiographic images show changes of rheumatoid arthritis long after irreversible joint damage has occured. With the advent of powerful disease-modifying drugs, there is a need for early demonstration of rheumatoid arthritis and a need to monitor progress of the disease and response to therapy. Advanced imaging techniques such as ultrasound and MRI have focussed on the demonstration and quantification of synovitis and erosions and allow early diagnosis of RA. The technology to quantify synovitis and erosions is developing rapidly and now allows change in disease activity to be assessed. However, problems undoubtedly exist in quantification techniques, and this review serves to highlight them. Much of the literature on advanced imaging in RA appears in rheumatological journals and may not be familiar to radiologists. This review article aims to increase the awareness of radiologists about this field and to encourage them to participate and contribute to the ongoing development of these modalities. Without this collaboration, it is unlikely that these modalities will reach their full potential in the field of rheumatological imaging. This review is in two parts. The first part addresses synovitis imaging. The second part will look at advanced imaging of erosions in RA. Part 2 of this article (Erosions) can be found at .     

Ultrasound appearance of knuckle pads

Objective We describe the ultrasound appearance of knuckle pads.Design and patients Retrospective analysis of imaging in a series of five patients initially referred for evaluation of periarticular soft-tissue swelling of the hands involving the dorsum of the PIP and MP joints. Two patients had associated Dupuytren’s contractures. Ultrasound and radiographs of the hands in all patients were reviewed and correlated with clinical history and physical exams.Results Radiographs in four patients demonstrated dorsal soft-tissue thickening. Ultrasound exams showed increased dorsal subcutaneous thickening, with either diffuse or focal hypoechoic areas corresponding to the areas of soft-tissue fullness identified on physical exam. No erosions or synovial proliferation were identified either by radiographs or ultrasound of the underlying joints.Conclusions Knuckle pads can sometimes be difficult to distinguish from synovitis on physical examination. Musculoskeletal ultrasound can quickly identify these superficial lesions and exclude underlying synovial proliferation.