Use of Tomosynthesis for Detection of Bone Erosions of the Foot in Patients With Established Rheumatoid Arthritis: Comparison With Radiography and CT

OBJECTIVE

The purpose of this study was to compare tomosynthesis with radiography for the detection of bone erosions of the foot in patients with established rheumatoid arthritis (RA) using MDCT as a reference standard.

SUBJECTS AND METHODS

Eighteen consecutive patients with established RA were included. Each patient underwent radiography, tomosynthesis, and CT examinations of the feet on the same day. Two radiologists independently determined the number of bone erosions and the Sharp-van der Heijde score with each of the three imaging modalities.

RESULTS

On a total of 216 joints from 18 patients, 216 bone erosions were detected on CT, 215 on tomosynthesis, and 181 with radiography. The mean (± SD) Sharp-van der Heijde score was equivalent for tomosynthesis (18.8 ± 16.8) and CT (19.8 ± 18.5) but was statistically lower for radiography (16.4 ± 18.0) (p = 0.030). The respective overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for tomosynthesis were 80%, 75%, 78%, 76%, and 80%, whereas the respective corresponding values for radiography were 66%, 81%, 74%, 77%, and 71%. The radiation burden of tomosynthesis was almost equivalent to that of radiography.

CONCLUSION

Tomosynthesis has a higher sensitivity than radiography to detect bone erosions of the foot in patients with established RA and imparts an almost equivalent radiation burden.

Mycobacterium kansasii causing chronic monoarticular synovitis in a patient with HIV/AIDS

Mycobacterium kansasii is a nontuberculous mycobacterium that primarily causes pulmonary disease in AIDS patients, however it has also been known, rarely, to result in skeletal infection. When skeletal infection occurs, the time from onset of symptoms to diagnosis is up to 5 years in previously reported cases. We describe a 48-year-old woman with HIV/AIDS who presented with chronic, isolated left knee pain and swelling of over two decades which had recently worsened. Radiographs and magnetic resonance imaging demonstrated marked subarticular erosions, synovial thickening, and bone marrow edema, which had progressed compared with prior imaging done seven years earlier. Synovial biopsy grew Mycobacterium kansasii. Following the presentation of our case, clinical and imaging findings, including the differential diagnosis, of monoarticular arthritis caused by Mycobacterium kansasii are reviewed and discussed.

Sarcoid tenosynovitis, rare presentation of a common disease. Case report and literature review

Sarcoidosis is an idiopathic inflammatory disorder characterized by the presence of non-caseating tissue granulomas most commonly affecting lungs, lymph nodes and skin. Sarcoid skeletal involvement is relatively uncommon and in particular tenosynovitis. We describe an unusual case of sarcoidosis presenting with granulomatous tenosynovitis as the only manifestation of the disease, illustrating the radiological findings on different modalities followed by a review of the literature. Radiologists and clinicians should be aware of tenosynovitis as a manifestation of sarcoidosis as early and therefore appropriate treatment significantly alters patient's outcome and prognosis.

Radiocarpal and Midcarpal Instability in Rheumatoid Patients: A Systematic Review

Background:

This study was aimed at identifying the criteria for the diagnosis of Radiocarpal instability in rheumatoid arthritis RA).

Methods:

The main databases were searched to identify studies describing the pathophysiology of Radiocarpal instability in patients with RA. We focussed on the epidemiology, radiographic parameters, criteria for instability and on treatment options. Results. In the search 108 articles were found, of these 12 studies were included for this review. Instability occurs in at an average of 35.2% of the rheumatoid wrists. The instability was found between 8 and 13 years after onset of rheumatoid arthritis. A strong correlation was found between instability, duration of RA and Larsen score. Several radiographic methods were described to evaluate Radiocarpal instability in RA. Several treatment options for instability in patients with RA are described. All with their own indications and limitations.

Conclusion:

On a standard AP radiograph deformity can be measured using the carpal height and the ulnar translation index of Chamay. This gives an indication for instability. For describing the deterioration of the joints the Larsen score is most used. If there are more radiographs in time the Simmen classification can be used. For real assessment of instability dynamic radiographs are needed.

Level of Evidence:

Level IV.

Detection and measurement of rheumatoid bone and joint lesions of fingers by tomosynthesis: a phantom study for reconstruction filter setting optimization

Rheumatoid arthritis (RA) is a systemic disease that is caused by autoimmunity. RA causes synovial proliferation, which may result in bone erosion and joint space narrowing in the affected joint. Tomosynthesis is a promising modality which may detect early bone lesions such as small bone erosion and slight joint space narrowing. Nevertheless, so far, the optimal reconstruction filter for detection of early bone lesions of fingers on tomosynthesis has not yet been known. Our purpose in this study was to determine an optimal reconstruction filter setting by using a bone phantom. We obtained images of a cylindrical phantom with holes simulating bone erosions (diameters of 0.6, 0.8, 1.0, 1.2, and 1.4 mm) and joint spaces by aligning two phantoms (space widths from 0.5 to 5.0 mm with 0.5 mm intervals), examining six reconstruction filters by using tomosynthesis. We carried out an accuracy test of the bone erosion size and joint space width, done by one radiological technologist, and a test to assess the visibility of bone erosion, done by five radiological technologists. No statistically significant difference was observed in the measured bone erosion size and joint space width among all of the reconstruction filters. In the visibility assessment test, reconstruction filters of Thickness+- and Thickness-- were among the best statistically in all characteristics except the signal-to-noise ratio. The Thickness+- and Thickness-- reconstruction filter may be optimal for evaluation of RA bone lesions of small joints in tomosynthesis.

Carpal pseudoerosions: a plain X-ray interpretation pitfall

OBJECTIVE

To examine in detail images of pseudoerosion of the wrist and hand on plain radiographs.

MATERIAL AND METHODS

The study was conducted with 28 cadaver wrists. During a single imaging session three techniques-plain radiography, tomosynthesis, and computed tomography-were used to visualize the wrist and hand specimens. For each technique, 20 radio-ulno-carpo-metacarpal sites known to present bone erosions in rheumatoid arthritis were analyzed by two radiologists using a standard system to score the cortical bone: normal, pseudoerosion, true erosion, or other pathology. Cohen's concordance analysis was performed to determine inter-observer and intra-observer (for the senior radiologist) agreement by site and by technique. Serial sections of two cadaver specimens were examined to determine the anatomical correlation of the pseudoerosions.

RESULTS

On the plain radiographs, the radiologists scored many images as pseudoerosion (7.3%), particularly in the distal ulnar portion of the capitate, the distal radial portion of the hamate, the proximal ulnar portion of the base of the third metacarpal, the proximal radial portion of the base of the fourth metacarpal, the distal ulnar portion of the hamate, and the proximal portion of the base of the fifth metacarpal. The computed tomography scan revealed that none of these doubtful images corresponded to true erosions. The anatomical correlation study showed that these images could probably be attributed to ligament insertions, thinner lamina, and enhanced cortical bone transparency.

CONCLUSION

Knowledge of the anatomical carpal localizations where pseudoerosions commonly occur is a necessary prerequisite for analysis of plain radiographs performed to diagnose or monitor rheumatoid arthritis.

The specificity of ultrasound-detected bone erosions for rheumatoid arthritis

BACKGROUND

Bone erosion is one of the hallmarks of rheumatoid arthritis (RA), but also seen in other rheumatic diseases. The objective of this study was to determine the specificity of ultrasound (US)-detected bone erosions (including their size) in the classical 'target' joints for RA.

METHODS

Patients fulfilling the diagnostic criteria for RA, psoriatic arthritis, osteoarthritis or gout in addition to healthy volunteers were included. The following areas were examined by US: distal radius and ulna, 2nd, 3rd and 5th metacarpophalangeal (MCP), 2nd and 3rd proximal interphalangeal (PIP) and 1st and 5th metatarsophalangeal (MTP) joints. All joints were scanned in four quadrants using both semiquantitative (0-3) and quantitative (erosion diameter) scoring systems.

RESULTS

310 subjects were recruited. The inter-reader and intrareader agreements were good to excellent. US-detected bone erosions were more frequent but not specific for RA (specificity 32.9% and sensitivity 91.4%). The presence of erosions with semiquantitative score ≥2 in four target joints (2nd, 5rd MCP, 5th MTP joints and distal ulna) was highly specific for RA (specificity 97.9% and sensitivity 41.4%). Size of erosion was found to be associated with RA. Erosions of any size in the 5th MTP joint were both specific and sensitive for RA (specificity 85.4% and sensitivity 68.6%).

CONCLUSIONS

The presence of US-detected erosions is not specific for RA. However, larger erosions in selected joints, especially 2nd and 5rd MCP, 5th MTP joints and distal ulna, were highly specific for and predictive of RA.

High-resolution ultrasound of the extrinsic carpal ligaments

Thanks to its intrinsic high spatial resolution, ultrasound is an ideal imaging modality for examining very thin, superficial structures, and this makes it very helpful in the evaluation of extrinsic carpal ligaments. These structures, which arise from the radius and ulna and insert on the carpal bones, are extremely important for wrist stability. Previous studies have assessed the use of ultrasound to study the extrinsic carpal ligaments in cadavers, healthy asymptomatic subjects, and patients with rheumatoid arthritis. In the present report, we review the normal anatomy, biomechanics, and ultrasound appearance of these ligaments.

Molecular characterization of rheumatoid arthritis with magnetic resonance imaging

Several recent advances in the field of magnetic resonance imaging (MRI) may transform the detection and monitoring of rheumatoid arthritis (RA). These advances depict both anatomic and molecular alterations from RA. Previous techniques could detect specific end products of metabolism in vitro or were limited to providing anatomic information. This review focuses on the novel molecular imaging techniques of hyperpolarized carbon-13 MRI, MRI with iron-labeled probes, and fusion of MRI with positron emission tomography. These new imaging approaches go beyond the anatomic description of RA and lend new information into the status of this disease by giving molecular information.

Assessment of collagen-induced arthritis using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles: correlation with 18F-fluorodeoxyglucose positron emission tomography data

OBJECTIVE

To evaluate the potential and correlation between near-infrared fluorescence (NIRF) imaging using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles (HGC-Cy5.5) and (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET) imaging of collagen-induced arthritis (CIA).

MATERIALS AND METHODS

We used 10 CIA and 3 normal mice. Nine days after the injecting collagen twice, microPET imaging was performed 40 minutes after the intravenous injection of 9.3 MBq (18)F-FDG in 200 µL PBS. One day later, NIRF imaging was performed two hours after the intravenous injection of HGC-cy5.5 (5 mg/kg). We assessed the correlation between these two modalities in the knees and ankles of CIA mice.

RESULTS

The mean standardized uptake values of (18)F-FDG for knees and ankles were 1.68 ± 0.76 and 0.79 ± 0.71, respectively, for CIA mice; and 0.57 ± 0.17 and 0.54 ± 0.20 respectively for control mice. From the NIRF images, the total photon counts per 30 mm(2) for knees and ankles were 2.32 ± 1.54 × 10(5) and 2.75 ± 1.51 × 10(5), respectively, for CIA mice, and 1.22 ± 0.27 × 10(5) and 0.88 ± 0.24 × 10(5), respectively, for control mice. These two modalities showed a moderate correlation for knees (r = 0.604, p = 0.005) and ankles (r = 0.464, p = 0.039). Moreover, both HGC-Cy5.5 (p = 0.002) and (18)F-FDG-PET (p = 0.005) imaging also showed statistically significant differences between CIA and normal mice.

CONCLUSION

NIRF imaging using HGC-Cy5.5 was moderately correlated with (18)F-FDG-PET imaging in the CIA model. As such, HGC-Cy5.5 imaging can be used for the early detection of rheumatoid arthritis.

Septic complications involving hand and wrist in patients with pre-existing rheumatoid arthritis: The role of magnetic resonance imaging and sonography

PURPOSE

Septic arthritis (SA), frequently involving hand and wrist, is common in rheumatoid arthritis (RA) patients due to immunomediated etiology of RA and immunosuppressive drug use. Clinical and laboratory features might not be useful to differentiate between RA relapse and superimposed SA. The role of magnetic resonance imaging (MRI) has been described in several studies. Our aim is to evaluate the role of ultrasonography (US).

MATERIAL AND METHODS

In the last 4 years 31 MRI of hand and wrist has been performed in the suspect of SA complicating RA. A 1.5 T unit (Siemens Symphony, Erlangen, Germany) with standardized protocol, involving the administration of contrast medium, was used. Also US with power Doppler evaluation was performed. A Philips IU22 US scanner was used.

RESULTS

Eleven points (according to Graif's study) were analyzed for every MRI and US. At MRI joint effusion (37.5% of RA relapse vs 100% superimposed SA) and soft tissue edema (25% vs 100%) were indicative of SA. At US joint effusion (31.3% of RA relapse vs 73.3% superimposed SA) and soft tissue edema (12.5% vs 60%) were indicative of SA.

CONCLUSION

Our results suggest that joint effusion and soft tissue edema are markers suggestive for superimposed SA and that MRI is more sensitive in their evaluation. Although US is less sensitive than MRI, the former is important in guiding invasive procedure and evaluating patients that cannot undergo MRI.

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.

High-resolution ultrasound evaluation of extrinsic wrist ligaments in patients affected by rheumatoid arthritis

OBJECTIVES

To evaluate the ultrasound features of the extrinsic wrist ligaments in rheumatoid arthritis (RA) patients in comparison with healthy volunteers.

METHODS

Twenty-one consecutive patients affected by RA (12 men, 9 women; mean age 57 ± 14.6 years) were compared with 21 controls (12, 9; 54 ± 12.1, respectively). Wrists were evaluated using ultrasound on both palmar and dorsal sides along each ligament, using carpal bones as references. The following ligaments were studied: radioscaphocapitate, radiolunotriquetral, palmar ulnolunate, palmar ulnotriquetral, dorsal radiotriquetral, dorsal ulnotriquetral, and radial collateral ligament. Ligament number and thickness were noted. Echotexture was rated as fibrillar, fragmented, or heterogeneous; the surface was rated as smooth or blurred.

RESULTS

The number of palmar ulnolunate and palmar ulnotriquetral ligaments detected by ultrasound in patients was significantly lower than in controls (P = 0.031 and P = 0.037, respectively). All ligaments had significantly more fragmented or heterogeneous echotexture and blurred surface and were significantly thinner in patients than in controls (P < 0.001). No correlation was found between ligament thickness and RA duration or clinical parameters.

CONCLUSIONS

Extrinsic wrist ligaments were less detectable and thinner in patients affected by RA compared with healthy volunteers matched for age and sex. Ligament thinning did not directly correlate with RA duration and clinical parameters.

KEY POINTS

• Ultrasound is increasingly used to evaluate normal anatomy of extrinsic wrist ligaments. • Extrinsic wrist ligaments are thinner in rheumatoid arthritis patients than in controls. • Extrinsic wrist ligaments are less easy to detect in rheumatoid arthritis patients. • Ligament thinning and detectability are not related to clinical parameters.

MR imaging assessment of inflammatory, crystalline-induced, and infectious arthritides

The role of magnetic resonance imaging in evaluating patients with inflammatory arthritides has evolved with the recent introduction of drugs capable of modifying disease activity and natural history. In conditions like rheumatoid arthritis, active synovitis and bone marrow inflammation precede and predict bone and cartilage erosion. These imaging findings identify patients who can be treated early and aggressively to prevent future morbidity. Similarly, in gout and other crystalline disorders, specific diagnosis aided by imaging may lead to earlier medical and surgical management. Infected joints need the most rapid identification to institute immediate therapy and prevent irreversible cartilage destruction.

Osteoimmunology and osteoporosis

The concept of osteoimmunology is based on growing insight into the links between the immune system and bone at the anatomical, vascular, cellular, and molecular levels. In both rheumatoid arthritis (RA) and ankylosing spondylitis (AS), bone is a target of inflammation. Activated immune cells at sites of inflammation produce a wide spectrum of cytokines in favor of increased bone resorption in RA and AS, resulting in bone erosions, osteitis, and peri-inflammatory and systemic bone loss. Peri-inflammatory bone formation is impaired in RA, resulting in non-healing of erosions, and this allows a local vicious circle of inflammation between synovitis, osteitis, and local bone loss. In contrast, peri-inflammatory bone formation is increased in AS, resulting in healing of erosions, ossifying enthesitis, and potential ankylosis of sacroiliac joints and intervertebral connections, and this changes the biomechanical competence of the spine. These changes in bone remodeling and structure contribute to the increased risk of vertebral fractures (in RA and AS) and non-vertebral fractures (in RA), and this risk is related to severity of disease and is independent of and superimposed on background fracture risk. Identifying patients who have RA and AS and are at high fracture risk and considering fracture prevention are, therefore, advocated in guidelines. Local peri-inflammatory bone loss and osteitis occur early and precede and predict erosive bone destruction in RA and AS and syndesmophytes in AS, which can occur despite clinically detectable inflammation (the so-called 'disconnection'). With the availability of new techniques to evaluate peri-inflammatory bone loss, osteitis, and erosions, peri-inflammatory bone changes are an exciting field for further research in the context of osteoimmunology.

Emerging role of ultrasonography in rheumatoid arthritis: optimizing diagnosis, measuring disease activity and identifying prognostic factors

Ultrasonography is a sensitive imaging modality that provides valuable information regarding early inflammatory changes that are not detected by clinical examination or X-rays, such as subclinical synovitis and erosions. This information may improve the management of rheumatoid arthritis by providing a more timely and accurate diagnosis, identifying poor prognostic factors, more accurately monitoring response to therapeutic intervention, improving treatment decisions and more accurately assessing remission. Ultrasonography could play a critical role in minimizing disease activity through strict monitoring and aggressive therapeutic adjustment, which has emerged as an approach to improve long-term outcomes for patients with rheumatoid arthritis.

Detection of vascularity in wrist tenosynovitis: power doppler ultrasound compared with contrast-enhanced grey-scale ultrasound

INTRODUCTION

We sought to assess vascularity in wrist tenosynovitis by using power Doppler ultrasound (PDUS) and to compare detection of intra- and peritendinous vascularity with that of contrast-enhanced grey-scale ultrasound (CEUS).

METHODS

Twenty-six tendons of 24 patients (nine men, 15 women; mean age ± SD, 54.4 ± 11.8 years) with a clinical diagnosis of tenosynovitis were examined with B-mode ultrasonography, PDUS, and CEUS by using a second-generation contrast agent, SonoVue (Bracco Diagnostics, Milan, Italy) and a low-mechanical-index ultrasound technique. Thickness of synovitis, extent of vascularized pannus, intensity of peritendinous vascularisation, and detection of intratendinous vessels was incorporated in a 3-score grading system (grade 0 to 2). Interobserver variability was calculated.

RESULTS

With CEUS, a significantly greater extent of vascularity could be detected than by using PDUS (P < 0.001). In terms of peri- and intratendinous vessels, CEUS was significantly more sensitive in the detection of vascularization compared with PDUS (P < 0.001). No significant correlation between synovial thickening and extent of vascularity could be found (P = 0.089 to 0.097). Interobserver reliability was calculated to be excellent when evaluating the grading score (κ = 0.811 to 1.00).

CONCLUSIONS

CEUS is a promising tool to detect tendon vascularity with higher sensitivity than PDUS by improved detection of intra- and peritendinous vascularity.

Emerging MRI methods in rheumatoid arthritis

New MRI techniques have been developed to assess not only the static anatomy of synovial hyperplasia, bone changes and cartilage degradation in patients with rheumatoid arthritis (RA), but also the activity of the physiological events that cause these changes. This enables an estimation of the rate of change in the synovium, bone and cartilage as a result of disease activity or in response to therapy. Typical MRI signs of RA in the pre-erosive phase include synovitis, bone marrow edema and subchondral cyst formation. Synovitis can be assessed by T2-weighted imaging, dynamic contrast-enhanced MRI or diffusion tensor imaging. Bone marrow edema can be detected on fluid-sensitive sequences such as short-tau inversion recovery or T2-weighted fast-spin echo sequences. Detection of small bone erosions in the early erosive phase using T1-weighted MRI has sensitivity comparable to CT. Numerous MRI techniques have been developed for quantitative assessment of potentially pathologic changes in cartilage composition that occur before frank morphologic changes. In this Review, we summarize the advances and new directions in the field of MRI, with an emphasis on their current state of development and application in RA.

Use of tomosynthesis for erosion evaluation in rheumatoid arthritic hands and wrists

PURPOSE

To compare tomosynthesis with radiography for the detection of hand and wrist bone erosions in patients with rheumatoid arthritis (RA), using multidetector computed tomography (CT) as the reference method.

MATERIALS AND METHODS

The study was approved by the local ethics committee, and written consent was obtained from all patients. From December 2008 to April 2009, 30 consecutive patients with RA were included in this prospective study. They underwent radiography, tomosynthesis, and CT of the most symptomatic hand and wrist on the same day. Two radiologists and one rheumatologist independently read images from the three imaging modalities.

RESULTS

A total of 232 erosions were detected with CT, while 199 and 140 erosions, respectively, were detected with tomosynthesis and radiography. More erosions were revealed with CT than with tomosynthesis and radiography (P < .0001); significantly more erosions were shown with tomosynthesis than with radiography (P < .0001). With CT as the reference method for bone erosions, the overall sensitivity, specificity, and accuracy of tomosynthesis were, respectively, 77.6%, 89.9%, and 83.1%. The corresponding values for radiography were 53.9%, 92%, and 70.9%. The sensitivity of each reader increased by roughly 20% with use of tomosynthesis.

CONCLUSION

The depiction of bone erosions of the hands and wrists is significantly greater with tomosynthesis than with radiography.

MR imaging of early rheumatoid arthritis

Early diagnosis and treatment have been recognized as essential for improving clinical outcomes in patients with early rheumatoid arthritis. However, diagnosis is somewhat difficult in the early stages of the disease because the diagnostic criteria were developed from data obtained in patients with established rheumatoid arthritis and therefore are not readily applicable. Magnetic resonance (MR) imaging is increasingly being used in the assessment of rheumatoid arthritis due to its capacity to help identify the key pathologic features of this disease entity at presentation. MR imaging has demonstrated greater sensitivity for the detection of synovitis and erosions than either clinical examination or conventional radiography and can help establish an early diagnosis of rheumatoid arthritis. It also allows the detection of bone marrow edema, which is thought to be a precursor for the development of erosions in early rheumatoid arthritis as well as a marker of active inflammation. In addition, MR imaging can help differentiate rheumatoid arthritis from some clinical subsets of peripheral spondyloarthropathies by allowing identification of inflammation at the insertions of ligaments and tendons (enthesitis).

Overview of imaging in inflammatory arthritis

Whether magnetic resonance imaging (MRI) or ultrasound (US) are chosen for the purposes of musculoskeletal interrogation depends upon a variety of factors ranging from the anatomy targeted to cost considerations and the time of acquisition. Newer technologies such as higher-strength MRI or 3D-US promise to help overcome some of the disadvantages of each option. Improving technical proficiency is the thrust of efforts to support more widespread application of sonographic assessment in various clinical arenas. Finally, these technologies offer the opportunity to diagnose inflammatory conditions at early stages of their disease progression.

Magnetic resonance spin-labeling perfusion imaging of synovitis in inflammatory arthritis at 3.0 T

OBJECTIVE

The aim of this study was to test the feasibility of arterial spin labeling (ASL) perfusion imaging of synovitis in inflammatory joint diseases on a clinical 3.0 T whole-body scanner.

MATERIALS AND METHODS

Fifteen patients (geometric mean 47 years, range 8-69 years) with different types of inflammatory arthritis of the finger or wrist joints participated in the study. In addition to conventional spin-echo and dynamic contrast-enhanced FLASH3D sequences, a novel spin-labeling technique (FAIR-TrueFISP) for quantitative assessment of tissue perfusion was applied. Perfusion maps were calculated pixel-wise by means of the extended Bloch equations.

RESULTS

Perfusion maps showed good image quality with clear visualization of hyperaemia in synovitis. The computed perfusion maps corresponded best to subtraction images of the dynamic series from 30 to 60 s after contrast-medium injection. The quantitative perfusion values of synovitis showed a good correlation with the disease activity. Perfusion values for inflamed synovium in phase of high activity were up to 230 ml/100 g tissue/min.

CONCLUSION

The proposed modality allows for the assessment of disease activity in arthritis without the application of contrast-medium offering a new tool for therapy monitoring. As the technique provides quantitative information on hyperaemia, it potentially offers new insights in the pathophysiology of arthritic diseases.

Automatic quantification of joint space narrowing and erosions in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic disease that affects and potentially destroys the joints of the appendicular skeleton. The precise and reproducible quantification of the progression of joint space narrowing and the erosive bone destructions caused by RA is crucial during treatment and in imaging biomarkers in clinical trials. Current manual scoring methods exhibit high interreader variability, even after intensive training, and thus, impede the efficient monitoring of the disease. We propose a fully automatic quantitative assessment of the radiographic changes that result from RA, to increase the accuracy, reproducibility, and speed of image interpretation. Initial joint location estimates are obtained by local linear mappings based on texture features. Bone contours are delineated by active shape models comprised of statistical models of bone shape and local texture. These models are refined by snakes which increase the accuracy and allow for a fitting of pathological deviations from the training population. The method then measures joint space widths and detects erosions on the bone contour. Joint space widths are measured with a coefficient of variation of 2%-7% for repeated measurements and erosion detection exhibits an area under the receiver operating characteristic (ROC) curve of 0.89. Model landmarks serve as a reference system along the contour. These landmarks enable the definition of joint regions and more specific follow-up monitoring. The automatic quantification allows for a remote analysis, relevant for multicenter clinical trials, and reduces the workload of clinical experts since parts of the process can be managed by nonexpert personnel.

Value of contrast-enhanced ultrasound in rheumatoid arthritis

The purpose of this review is to describe the spectrum of sonographic findings in rheumatic diseases with respect to the diagnostic potential using US contrast media which prove activity or inactivity in synovial tissue where new treatment regimes target. Synovial activity can be found in non-erosive and erosive forms of primary and secondary osteoarthritis, and in inflammatory forms of joint diseases like rheumatoid arthritis and peripheral manifestations of spondyloarthritis including, ankylosing spondylitis, Reiter's syndrome, psoriatic arthritis and enteropathic arthritis. It can also be present in metabolic and endocrine forms of arthritis, in connective tissue arthropathies like systemic lupus erythematosus or scleroderma and in infectious arthritis. Ultrasound should be used as first-line imaging modality in suspected early cases of RA and other forms of arthritis, whereas contrast-enhanced ultrasound (CEUS) can further enable for sensitive assessment of vascularity which correlates with disease activity.

Metatarsalgias: diagnóstico diferencial por meio da ressonância magnética

Várias lesões podem causar metatarsalgia, cujas manifestações clínicas podem ser inespecíficas. As imagens de ressonância magnética, associadas a outros métodos de imagem e dados clínicos, freqüentemente podem contribuir na detecção dessas lesões e possibilitar que um diagnóstico relativamente preciso seja considerado. Nosso objetivo é descrever e ilustrar, por meio de imagens de ressonância magnética, as principais doenças que causam metatarsalgia.

[Arthroplasty of the rheumatoid hand. Pre- and postoperative imaging with special consideration of biomechanical and pathobiomechanical aspects and its radiological evaluation]

Radiology plays a key role when the indications for arthroplasties of the hand and finger joints are determined and for the postoperative follow-up. On the one hand, the degree of inflammatory changes in all affected compartments is to be evaluated and graded; on the other hand, conventional radiograms allow for a first assessment of possible joint instability and impaired biomechanics. Both aspects influence the choice of the proper surgical therapeutic strategy. Osteolysis, deformity, fracture, prosthesis loosening or failure, heterotopic ossification, and foreign body-associated formation of granulation tissue are complications which can be detected on follow-up radiographs early on.