Imaging the joints in early rheumatoid arthritis

Segmentation of bones & MCP joint region of the hand from ultrasound images

Rheumatic arthritis (RA) is an autoimmune disease that causes irreversible damage to joints and other physiological structures. The Metacarpophalangeal (MCP) joint is one of the first regions to suffer alterations. These alterations are visible with high frequency ultrasound devices, which are used to quantify inflammatory activity in the MCP due to RA. The accurate segmentation of the bone surface and the identification of the MCP capsule region remains a challenge in ultrasound image processing. In this article we aim to make a contribution to this problem by incorporating prior knowledge of the bone and joint regions anatomy into our segmentation algorithm. The log Gabor filter is used for speckle noise reduction and to extract ridge-like structures from the images, while the phase is left unchanged. After thresholding, scores are generated, based on the intensities and areas of the resulting regions, enabling the selection of the structure that best matches the bone. Finally, segmented joint bones are processed to calculate the initial seeds of joint capsule region. Experimental results demonstrate the accuracy of the proposed segmentation algorithm. The mean pixel error between the automatic segmentation and the reference images were 4.4 pixel. The bone regions not segmented were, on average, 5.4%.

Bone erosions in rheumatoid arthritis: ultrasound findings in the early stage of the disease

OBJECTIVE

The objective of this study was to determine the prevalence and distribution of bone erosions detectable by US in patients with early RA (ERA) in comparison with long-standing RA (LSRA), other erosive diseases and healthy controls.

METHODS

Thirty patients with ERA and 80 patients with LSRA were consecutively recruited. Thirty patients with PsA, 15 with primary OA, 10 with gout and 20 healthy subjects were included as controls. Bone erosions were investigated at the following anatomical sites: the second and fifth metacarpal heads, the ulnar head and the first and fifth metatarsal heads, bilaterally. Dorsal, volar and lateral aspects were explored on longitudinal and transverse views.

RESULTS

At least one US bone erosion was found in 20 (66.7%) of 30 patients with ERA and in 10 (33%) of them it was found on the fifth metatarsal head. Bone erosions were most frequently found on the lateral quadrants of all scanned anatomical sites. If the second and fifth metacarpal heads and the fifth metatarsal head were scanned, an erosive disease could be found in 60% of ERA patients. The first metatarsal head was most frequently involved in the disease control group.

CONCLUSION

This study found a high percentage of ERA patients with US bone erosions, with the fifth metatarsal head and the lateral aspects the most frequently involved site and quadrants. US scanning for bone erosions on a few target joints was found feasible and provided information not obtainable with clinical examination.

Usefulness of ultrasound imaging in detecting psoriatic arthritis of fingers and toes in patients with psoriasis

Background. Given that clinical evaluation may underestimate the joint damage and that early treatment can slow down psoriatic arthritis (PsA) progression, screening psoriasis patients with imaging tools that can depict early PsA changes would entail clear benefits. Objective. To compare the ability of X-ray and ultrasound (US) examination in detecting morphological abnormalities consistent with early PsA in patients with psoriasis, using rheumatological evaluation as the gold standard for diagnosis. Methods. Patients with chronic plaque psoriasis and no previous PsA diagnosis attending our outpatient dermatology clinic and reporting finger/toe joint and/or tendon pain underwent X-ray and US evaluation; they were subsequently referred to a rheumatologist for clinical examination and review of imaging findings. Results. Abnormal US and/or X-ray findings involving at least one finger and/or toe (joints and/or tendons) were seen in 36/52 patients: 11 had one or more X-ray abnormalities, including erosion, joint space narrowing, new bone formation, periarticular soft tissue swelling, and periarticular osteoporosis; 36 had suspicious changes on US. Conclusion. US proved valuable in detecting joint and/or tendon abnormalities in the fingers and toes of patients with suspicious changes. The dermatologist should consider US to obtain an accurate assessment of suspicious findings.

Optical imaging: new tools for arthritis

Conventional radiography, ultrasound, CT, MRI, and nuclear imaging are the current imaging modalities used for clinical evaluation of arthritis which is highly prevalent and a leading cause of disability. Some of these types of imaging are also used for monitoring disease progression and treatment response of arthritis. However, their disadvantages limit their utilities, such as ionizing radiation for radiography, CT, and nuclear imaging; suboptimal tissue contrast resolution for radiography, CT, ultrasound, and nuclear imaging; high cost for CT and MRI and nuclear imaging; and long data-acquisition time with ensuing patient discomfort for MRI. Recently, there have been considerable advances in nonionizing noninvasive optical imaging which has demonstrated promise for early diagnosis, monitoring therapeutic interventions and disease progression of arthritis. Optical based molecular imaging modalities such as fluorescence imaging have shown high sensitivity in detection of optical contrast agents and can aid early diagnosis and ongoing evaluation of chronic inflammatory arthritis. Optical transillumination imaging or diffuse optical tomography may differentiate normal joint clear synovial fluid from turbid and pink medium early in the inflammatory process. Fourier transform infrared spectroscopy has been used to evaluate fluid composition from joints affected by arthritis. Hemodynamic changes such as angiogenesis, hypervascularization, and hypoxia in arthritic articular tissue can potentially be observed by diffuse optical tomography and photoacoustic tomography. Optical measurements could also facilitate quantification of hemodynamic properties such as blood volume and oxygenation levels at early stages of inflammatory arthritis. Optical imaging provides methodologies which should contribute to detection of early changes and monitoring of progression in pathological characteristics of arthritis, with relatively simple instrumentation.

Use of 99mTc-anti-CD3 scintigraphy in the differential diagnosis of rheumatic diseases

OBJECTIVES

The aim of this study was to assess the use of anti-CD3, labelled with technetium-99m scintigraphy, for evaluating the joints of patients with RA, juvenile idiopathic arthritis (JIA), OA and gouty arthritis, and to establish the diagnosis parameters for each disease.

METHODS

We evaluated 2044 joints from 77 patients with rheumatic diseases. The clinical evaluation consisted of laboratory assays; examination for joint inflammation (pain and/or oedema); and for patients with RA, the disease activity score of 28 joints. To evaluate the sensitivity and specificity of 99mTc-anti-CD3 in detecting disease activity, patients received an injection of the radiopharmaceutical compound 99mTc-anti-CD3, and underwent a scintigraphy scan 1 h later. Scanning was repeated 3 h later. As a control, after 2 days, the patient was injected with 99mTc-non-specific human immunoglobulins, and scintigraphy scanning performed at 1 and 3 h after the injection. The intensity of uptake and the pattern of activity were defined, and Spearman's correlation and analysis of variance used for statistical evaluation.

RESULTS

Diagnosis criteria were established for 99mTc-anti-CD3 uptake in different diseases. RA and JIA showed joint uptake with progressive increase in late images. Gouty arthritis showed joint uptake with decrease during the late images. Joint uptake was low or absent in patients with OA, although when present the joint uptake decreased during the examination.

CONCLUSION

99mTc-anti-CD3 scintigraphy is a useful method in the differential diagnosis of rheumatic diseases.

Role of ultrasound in assessment of early rheumatoid arthritis

This report reviews imaging methods used for diagnosis and monitoring of rheumatoid arthritis, with emphasis on the role of ultrasonography. Traditionally, conventional radiography has been useful in detecting and monitoring the extent of joint destruction in rheumatic disease. However, it is particularly difficult to detect pathological joint changes in the early stages. Magnetic resonance imaging is able to detect inflammation of the synovial membrane and erosions but is limited by cost and availability. Ultrasound has recently emerged as a useful and potentially reliable method for assessing the degree of joint inflammation and erosion in patients with early rheumatoid arthritis.

Diagnostic quality and scoring of synovitis, tenosynovitis and erosions in low-field MRI of patients with rheumatoid arthritis: a comparison with conventional MRI

OBJECTIVE

To compare dedicated low-field MRI (lfMRI) with conventional MRI (cMRI) in the detection and scoring of synovitis, tenosynovitis and erosions in patients with rheumatoid arthritis.

PATIENTS AND METHODS

The wrist and finger joints of 17 patients with rheumatoid arthritis (median (range) disease duration 8 years (7-12); Disease Activity Score 3.3 (2.6-4.5)) were examined by 0.2 T lfMRI and 1.5 TcMRI. The protocols comprised coronal spin-echo and three-dimensional gradient-echo sequences before and after contrast medium administration. Synovitis of the metacarpophalangeal and proximal interphalangeal joints 2-5 and the wrist joints was scored according to Outcome Measures in Rheumatology recommendations. Tenosynovitis and erosions were scored using 4-point and 6-point scales, respectively. The results were analysed by calculating kappa values and performing McNemar's test intra-individually on a joint-by-joint basis.

RESULTS

Agreement between the two MRI techniques was good to excellent for synovitis and erosions, and moderate for tenosynovitis. Of the 306 joints evaluated, 245 and 200 joints showed synovitis in lfMRI and cMRI, respectively. Scoring of synovitis of the finger joints yielded kappa values from 0.69 to 0.94. Of the 68 flexor tendons evaluated, tenosynovitis was diagnosed by lfMRI in 24 and by cMRI in 33 instances. Of the 391 bones evaluated, 154 and 139 showed erosions in lfMRI and cMRI, respectively. kappa values for erosion scores were between 0.65 and 1.

CONCLUSION

Dedicated, lfMRI shows high agreement with cMRI in diagnosing and scoring synovitis, tenosynovitis and erosions in rheumatoid arthritis when using standardised scoring systems.

Prospective 7 year follow up imaging study comparing radiography, ultrasonography, and magnetic resonance imaging in rheumatoid arthritis finger joints

OBJECTIVE

To perform a prospective long term follow up study comparing conventional radiography (CR), ultrasonography (US), and magnetic resonance imaging (MRI) in the detection of bone erosions and synovitis in rheumatoid arthritis (RA) finger joints.

METHODS

The metacarpophalangeal and proximal interphalangeal joints II-V (128 joints) of the clinically dominant hand of 16 patients with RA were included. Follow up joint by joint comparisons for erosions and synovitis were made.

RESULTS

At baseline, CR detected erosions in 5/128 (4%) of all joints, US in 12/128 (9%), and MRI in 34/128 (27%). Seven years later, an increase of joints with erosions was found with CR (26%), US (49%) (p<0.001 each), and MRI (32%, NS). In contrast, joint swelling and tenderness assessed by clinical examination were decreased at follow up (p = 0.2, p<0.001). A significant reduction in synovitis with US and MRI (p<0.001 each) was seen. In CR, 12 patients did not have any erosions at baseline, while in 10/12 patients erosions were detected in 25/96 (26%) joints after 7 years. US initially detected erosions in 9 joints, of which two of these joints with erosions were seen by CR at follow up. MRI initially found 34 erosions, of which 14 (41%) were then detected by CR.

CONCLUSION

After 7 years, an increase of bone erosions was detected by all imaging modalities. In contrast, clinical improvement and regression of synovitis were seen only with US and MRI. More than one third of erosions previously detected by MRI were seen by CR 7 years later.

Ultrasound and power Doppler evaluation of the hand and wrist in patients with psoriatic arthritis

PURPOSE

To evaluate the ability of high-resolution and power Doppler sonography in detecting joint and tendon abnormalities in patients with psoriatic arthritis (PsA) of the hands and wrists compared with clinical and radiological findings.

MATERIAL AND METHODS

Thirty-six patients with psoriatic arthritis of the hands and wrists and 10 healthy controls were examined with ultrasound (US). The degree of synovial proliferation, tenosynovitis, presence of joint effusion as well as the vascularity of synovial tissue was estimated. US findings were scored using a newly devised scoring system.

RESULTS

Thirty-two patients had articular synovial proliferation and/or tenosynovitis/ tendinitis or joint effusion in one or more joints according to US. Twenty-two patients had tendon changes; only five had joint effusion. The synovial, Doppler, and total articular-teno scores were all significantly correlated to the number of swollen joints. The scores, however, did not correlate to other clinical or laboratory measurements of disease activity.

CONCLUSION

US proved effective in demonstrating PsA involvement of the hands and wrists and was more sensitive than clinical examination in detecting pathology. Long-term follow-up studies are needed to evaluate whether this can change the traditional approach for assessing involvement of joints and tendons in PsA.

Magnetic resonance imaging of inflammation with a specific selectin-targeted contrast agent

E-selectin-targeted contrast enhancement of blood vessels in inflamed tissues was investigated with a new contrast agent, Gd-DTPA-B(sLe(x))A, which was recently obtained by grafting a synthetic mimetic of sialyl-Lewis(x), an E-selectin ligand, onto Gd-DTPA. The pharmacokinetics, biodistribution, and potential to image inflammation by MRI of this E-selectin-targeted contrast agent were evaluated. The inhibition (by 15-34%) produced by Gd-DTPA-B(sLe(x))A on Sialyl Le(x)-PAA-biotin binding to E-selectin confirmed the specific interaction of the new contrast agent with this adhesion molecule. Gd-DTPA-B(sLe(x))A was tested at a dose of 0.1 mmol/kg b.w. on mice and rats in a fulminant hepatitis model induced by the co-administration of D-galactosamine and E. coli lipopolysaccharide. A significant and prolonged contrast enhancement between blood vessels and liver parenchyma was obtained in pathological conditions, which attests to the specificity of the agent for E-selectin. The prolonged vascular residence (48.9 min in hepatitis vs. 29.8 min in healthy animals), as evidenced by the pharmacokinetic characterization, suggests that Gd-DTPA-B(sLe(x))A interacts with the specific receptors expressed during inflammation. The biodistribution of the compound indicates its retention in inflamed liver by both specific mechanisms and nonspecific accumulation due to the necrotic lesions. The same mechanisms are invoked to account for its retention in the spleen.

Quantitative Analysis of Micro-CT Imaging and Histopathological Signatures of Experimental Arthritis in Rats

Micro-computed tomographic (micro-CT) imaging provides a unique opportunity to capture 3-D architectural information in bone samples. In this study of pathological joint changes in a rat model of adjuvant-induced arthritis (AA), quantitative analysis of bone volume and roughness were performed by micro-CT imaging and compared with histopathology methods and paw swelling measurement. Micro-CT imaging of excised rat hind paws (n = 10) stored in formalin consisted of approximately 600 30-mum slices acquired on a 512 x 512 image matrix with isotropic resolution. Following imaging, the joints were scored from H&E stained sections for cartilage/bone erosion, pannus development, inflammation, and synovial hyperplasia. From micro-CT images, quantitative analysis of absolute bone volumes and bone roughness was performed. Bone erosion in the rat AA model is substantial, leading to a significant decline in tarsal volume (27%). The result of the custom bone roughness measurement indicated a 55% increase in surface roughness. Histological and paw volume analyses also demonstrated severe arthritic disease as compared to controls. Statistical analyses indicate correlations among bone volume, roughness, histology, and paw volume. These data demonstrate that the destructive progression of disease in a rat AA model can be quantified using 3-D micro-CT image analysis, which allows assessment of arthritic disease status and efficacy of experimental therapeutic agents.

Documenting damage progression in a two-year longitudinal study of rheumatoid arthritis patients with established disease (the DAMAGE study cohort): Is there an advantage in the use of magnetic resonance imaging as compared with plain radiography?

OBJECTIVE

In early rheumatoid arthritis (RA), longitudinal studies have demonstrated that magnetic resonance imaging (MRI) is more sensitive than radiography in demonstrating progressive erosive joint damage. The present study evaluated the progression of erosive damage in patients with established RA by using limited field of view MRI and comparing the results with those obtained by radiography.

METHODS

MRI and radiographic studies were available from 47 of 60 patients enrolled in a 2-year RA observational study. MRI of the metacarpophalangeal (MCP) joints was performed at baseline and 2 years later, and a single observer scored all of the MR images with the use of an MRI scoring method developed by the Outcome Measures in Rheumatology Clinical Trials MRI RA study group. MR images from 14 patients were reread by the same observer after 1 week to assess intraobserver reliability. Radiographs were obtained at baseline and at 2 years, and were scored by an observer using the Scott modification of the Larsen score. Radiographs from 14 patients were reread after 1 week to assess the intraobserver reliability. The smallest detectable difference (SDD) was calculated for the MRI scores, the total Larsen scores, and the Larsen scores of the dominant-hand MCP joints (MCPs 2-5) for direct comparison with the MRI results.

RESULTS

The median disease duration was 5.1 years (range 0.5-29 years). Evidence of erosion progression was identified by MRI in 30 patients (64%). The SDD based on the intraobserver scores was calculated as +/-3.25 units. Using this result, 11 patients (23%) showed evidence of erosion progression on MRI that was greater than the SDD. The SDD for progression based on the intraobserver total Larsen radiographic scores was 0.77 units, and the SDD for the Larsen scores of the dominant-hand MCP joints was 1.55 units. On the basis of these results, radiographic progression was noted in 19 patients (40%) by the total Larsen score and 7 patients (15%) by the dominant-hand MCP Larsen score. The most striking finding was that although MRI and radiograph scores identified a similar group of patients as having progression of joint damage, the radiographs of both hands appeared to be more responsive to change, albeit with the caveat that radiographic progression was most marked outside the dominant-hand MCP joints.

CONCLUSION

There was no clear advantage of MRI with a limited field of view as compared with radiographic imaging of both hands in detecting progression of joint damage over 2 years in this group of patients with established RA. The conclusion drawn from this study is not that radiographs are better than MRI or vice versa, but that careful analysis is required to determine the optimal imaging method, or combination of imaging methods, for each study population, depending on the objective and duration of the study.

Rheumatoid arthritis of the shoulder joint: Comparison of conventional radiography, ultrasound, and dynamic contrast-enhanced magnetic resonance imaging

OBJECTIVE

To determine the role of ultrasound and magnetic resonance imaging (MRI) compared with conventional radiography in the detection of chronic and acute inflammatory manifestations of rheumatoid arthritis (RA) of the shoulder joint.

METHODS

Forty-three consecutive patients with known RA prospectively underwent clinical examination, radiography, ultrasound, and MRI of the shoulder joints. Each patient was assigned a clinical/laboratory score consisting of 7 parameters, including measurements of shoulder mobility, the erythrocyte sedimentation rate, and C-reactive protein level. Conventional radiography was standardized and performed in 2 planes. Ultrasound was performed in 10 predefined planes using a 7.5-MHz linear transducer. MRI at 1.5T comprised transverse and oblique coronal T1- and T2*-weighted fast spin-echo, gradient-echo (GRE), and inversion-recovery sequences with a matrix size of up to 512 pixels. A dynamic T1-weighted GRE sequence was acquired with intravenous administration of contrast medium. Erosions were assessed using all 3 imaging techniques on a 4-point scale. Soft-tissue involvement was evaluated according to the presence of synovitis, tenosynovitis, and bursitis on ultrasound and MRI. The results in the study group were compared with those obtained in a control group of 10 patients with shoulder pain.

RESULTS

In the study group, erosions of the humeroscapular joint were detected by conventional radiography in 26 patients, by ultrasound in 30 patients, and by MRI in 39 patients; the differences were statistically significant for the comparisons of conventional radiography with MRI and for ultrasound versus MRI (P < 0.0001). Conventional radiography detected 12 erosions of the scapula and MRI detected 15. Synovitis was demonstrated in 12 patients by ultrasound and in 27 patients by MRI (P = 0.0003). Tenosynovitis was observed in 15 patients by ultrasound and in 28 patients by MRI (P = 0.0064). Bursitis was detected in 13 patients by ultrasound and in 18 patients by MRI. The findings on dynamic contrast-enhanced MRI correlated significantly with the detection of synovitis by ultrasound and erosions by static MRI (P < 0.05).

CONCLUSION

Ultrasound and MRI supplement conventional radiography in assessing the shoulder joint. Although conventional radiography can be used as the sole method of following up known joint destruction in RA, ultrasound and, preferably, MRI are recommended as additional techniques in the initial diagnostic evaluation when radiography yields negative results.

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.

Imaging in rheumatoid arthritis--why MRI and ultrasonography can no longer be ignored

Implementing the modern treatment strategy in rheumatoid arthritis (RA), i.e. early initiation and optimal adjustments of aggressive therapies, requires methods for early diagnosis and sensitive monitoring of the disease process. In rheumatoid arthritis clinical trials and routine management, conventional radiography is the pivotal method for diagnosing and monitoring structural joint damage. However, it is insensitive to bone damage at its earliest stages and totally incapable of capturing the primary feature of rheumatoid disease, the synovitis. In comparison with radiography, magnetic resonance imaging (MRI) offers assessment of bone damage with improved sensitivities to early pathology and to change. In addition, detailed assessment of soft tissue changes, including synovitis and tenosynovitis, is possible and MRI findings are of prognostic value for the long-term radiological outcome. Ultrasonography (US) is less validated than MRI, but available data suggests that US offers comparable information on both inflammatory and destructive changes in RA finger and toe joints. Issues of reliability, standardization and documentation limit its value in clinical trials, This article reviews current knowledge on conventional radiography, computed tomography, MRI and US for assessment of peripheral joints in RA. The rationale is provided for MRI being the new gold standard for assessment of RA joints and US becoming a routine bedside tool for improved joint assessments and injections by rheumatologists. Pursuing the goal of improving patient care and disease outcome, rheumatologists can no longer afford to ignore MRI and US as means to measure disease activity and joint damage in rheumatoid arthritis.

Magnetic resonance imaging: opportunities for rheumatoid arthritis disease assessment and monitoring long-term treatment outcomes

Early diagnosis of rheumatoid arthritis (RA) combined with early initiation of an appropriate treatment regimen is acknowledged as an important factor in improving clinical outcomes in patients with RA. Early diagnosis allows treatment intervention to occur sooner in order to inhibit the progression of structural joint damage as well as providing improved patient quality of life. Unfortunately, early diagnosis has been challenging due to the non-specific signs and symptoms associated with many polyarthropathies and the lack of accurate definitive diagnostic tests that can accurately classify RA at presentation. The emphasis on early diagnosis has fueled the need for powerful, sensitive, non-invasive imaging techniques that not only accurately define RA and give an indication of prognosis, but can also serve as a tool to monitor long-term treatment outcomes. This article reviews the potential uses of magnetic resonance imaging as a tool for the classification, documentation, and clinical monitoring of RA.