M. Backhaus

Guidelines for musculoskeletal ultrasound in rheumatology

Within the past decade, musculoskeletal ultrasound (US) has become an established imaging technique for the diagnosis and follow up of patients with rheumatic diseases.1-5 This has been made possible through technological improvements, resulting in faster computers and higher frequency transducers. US is most commonly used in the assessment of soft tissue disease or detection of fluid collection and can also be used to visualise other structures, such as cartilage and bone surfaces.6 7 Owing to the better axial and lateral resolution of US, even minute bone surface abnormalities may be depicted. Thus destructive and/or reparative/hypertrophic changes on the bone surface may be seen before they are apparent on plain x rays or even magnetic resonance imaging.8 However, US wave frequencies cannot penetrate into bone, therefore imaging of intra-articular disease is usually not possible. The “real time” capability of US allows dynamic assessment of joint and tendon movements, which can often aid the detection of structural abnormalities. Advantages of US include its non-invasiveness, portability, relative inexpensiveness, lack of ionising radiation, and its ability to be repeated as often as necessary, making it particularly useful for the monitoring of treatment. US can also be used for guidance of aspiration, biopsy, and injection treatment.9 Most musculoskeletal work is performed using “grey scale”, which means images are produced in a black and white format; each white dot in the image represents a reflected sound wave. Sound waves travel in a similar way to light waves and therefore the denser a material is—for example, bone cortex, the more reflective it is and the whiter it appears on the screen. Water is the least reflective body material and therefore appears as black as the sound waves travel straight through it. Newer US techniques, which are currently being evaluated, include colour and power …

Arthritis of the finger joints: A comprehensive approach comparing conventional radiography, scintigraphy, ultrasound, and contrast-enhanced magnetic resonance imaging

OBJECTIVE A prospective study was performed comparing conventional radiography, 3-phase bone scintigraphy, ultrasound, and magnetic resonance imaging (MRI) with precontrast and dynamic postcontrast examinations in 60 patients with various forms of arthritis including rheumatoid arthritis (RA), spondyl-arthropathy, and arthritis associated with connective tissue disease. METHODS A total of 840 finger joints were examined clinically and by all 4 imaging methods. Experienced investigators blinded to the clinical findings and diagnoses analyzed all methods independently of each other. The patients were divided into 2 groups. Group 1 included 32 patients (448 finger joints) without radiologic signs of destructive arthritis (Larsen grades 0-1) of the evaluated hand and wrist and group 2 included 28 patients (392 finger joints) with radiographs revealing erosions (Larsen grade 2) of the evaluated hand and/or wrist. RESULTS Clinical evaluation, scintigraphy, MRI, and ultrasound were each more sensitive than conventional radiography in detecting inflammatory soft tissue lesions as well as destructive joint processes in arthritis patients in group 1. All differences were statistically significant. We found ultrasound to be even more sensitive than MRI in the detection of synovitis. MRI detected erosions in 92 finger joints (20%; 26 patients) in group 1 that had not been detected by conventional radiography. CONCLUSION Our data indicate that MRI and ultrasound are valuable diagnostic methods in patients with arthritis who have normal findings on radiologic evaluation.

Quantitative analyses of sacroiliac biopsies in spondyloarthropathies: T cells and macrophages predominate in early and active sacroiliitis- cellularity correlates with the degree of enhancement detected by magnetic resonance imaging.

OBJECTIVE Sacroiliitis is a hallmark of the spondyloarthropathies (SpA). The degree of inflammation can be quantified by magnetic resonance imaging (MRI). The aim of this study was to further elucidate the pathogenesis of SpA by quantitative cellular analysis of immunostained sacroiliac biopsy specimens and to compare these findings with the degree of enhancement in the sacroiliac joints (SJ) as detected by dynamic MRI. METHODS The degree of acute sacroiliitis detected by MRI after intravenous administration of gadolinium-DTPA was quantitatively assessed by calculating the enhancement observed in the SJ and chronic changes were graded as described in 32 patients with ankylosing spondylitis (n=18), undifferentiated SpA (n=12) and psoriatic arthritis (n=2). Back pain was graded on a visual analogue scale (VAS, 0–10) and disease duration (DD) was assessed. Shortly after MRI, SJ of patients with VAS > 5 were biopsied guided by computed tomography. Immunohistological examination was performed using the APAAP technique; only whole sections > 3 mm were counted. RESULTS By MRI, chronic changes ⩽ grade II were detected in nine patients (group I, DD 2.5 (SD 2.9) years) and > II in 13 patients (group II, DD 7.3 (SD 4.8) years), while enhancement < 70% was found in eight (group A, DD 5.6 (SD 3.3) years) and > 70% in 12 patients (group B, DD 4.7 (SD 5.8) years). The relative percentage of cartilage (78–93%), bone (7–18%) and proliferating connective tissue (1–4%) was comparable between the groups (range). There were more inflammatory cells in group I compared with group II (mean (SD) 26.7(20.1) versus 5.3 (5.2), p=0.04) and group A compared with B (21.8 (17.3) versus 6.0 (5.6), p=0.05) cells/10 mm2), T cells (10.9 (8.5)) being slightly more frequent than macrophages (9.6 (16.8/10 mm2)). Clusters of proliferating fibroblasts were seen in three and new vessel formation in seven cases. CONCLUSION This study shows that T cells and macrophages are the most frequent cells in early and active sacroiliitis in SpA. The correlation of cellularity and MRI enhancement provides further evidence for the role of dynamic MRI to detect early sacroiliitis.

Evaluation of a novel 7‐joint ultrasound score in daily rheumatologic practice: A pilot project

OBJECTIVE To introduce a new standardized ultrasound score based on 7 joints of the clinically dominant hand and foot (German US7 score) implemented in daily rheumatologic practice. METHODS The ultrasound score included the following joints of the clinically dominant hand and foot: wrist, second and third metacarpophalangeal and proximal interphalangeal, and second and fifth metatarsophalangeal joints. Synovitis and synovial/tenosynovial vascularity were scored semiquantitatively (grade 0-3) by gray-scale (GS) and power Doppler (PD) ultrasound. Tenosynovitis and erosions were scored for presence. The scoring range was 0-27 for GS synovitis, 0-39 for PD synovitis, 0-7 for GS tenosynovitis, 0-21 for PD tenosynovitis, and 0-14 for erosions. Patients with arthritis were examined at baseline and after the start or change of disease-modifying antirheumatic drug (DMARD) and/or tumor necrosis factor alpha (TNFalpha) inhibitor therapy 3 and 6 months later. C-reactive protein level, erythrocyte sedimentation rate, rheumatoid factor, anti-cyclic citrullinated peptide, Disease Activity Score in 28 joints (DAS28), and radiographs of the hands and feet were performed. RESULTS One hundred twenty patients (76% women) with rheumatoid arthritis (91%) and psoriatic arthritis (9%) were enrolled. In 52 cases (43%), erosions were seen in radiography at baseline. Patients received DMARDs (41%), DMARDs plus TNFalpha inhibitors (41%), or TNFalpha inhibitor monotherapy (18%). At baseline, the mean DAS28 was 5.0 and the synovitis scores were 8.1 in GS ultrasound and 3.3 in PD ultrasound. After 6 months of therapy, the DAS28 significantly decreased to 3.6 (Delta = 1.4), and the GS and PD ultrasound scores significantly decreased to 5.5 (-32%) and 2.0 (-39%), respectively. CONCLUSION The German US7 score is a viable tool for examining patients with arthritis in daily rheumatologic practice because it significantly reflects therapeutic response.

Prospective two year follow up study comparing novel and conventional imaging procedures in patients with arthritic finger joints

Objective: To carry out a prospective two year follow up study comparing conventional radiography, three-phase bone scintigraphy, ultrasonography (US), and three dimensional (3D) magnetic resonance imaging (MRI) with precontrast and dynamic postcontrast examination in detecting early arthritis. The aim of the follow up study was to monitor the course of erosions during treatment with disease modifying antirheumatic drugs by different modalities and to determine whether the radiographically occult changes like erosive bone lesions of the finger joints detected by MRI and US in the initial study would show up on conventional radiographs two years later. Additionally, to study the course of soft tissue lesions depicted in the initial study in comparison with the clinical findings. Methods: The metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints (14 joints) of the clinically more severely affected hand (soft tissue swelling and joint tenderness) as determined in the initial study of 49 patients with various forms of arthritis were examined twice. The patients had initially been divided into two groups. The follow up group I included 28 subjects (392 joints) without radiographic signs of destructive arthritis (Larsen grades 0–1) of the investigated hand and wrist, and group II (control group) included 21 patients (294 joints) with radiographs showing erosions (Larsen grade 2) of the investigated hand or wrist, or both, at the initial examination. Results: (1) Radiography at the two year follow up detected only two erosions (two patients) in group I and 10 (nine patients) additional erosions in group II. Initial MRI had already detected both erosions in group I and seven (seven patients) of the 10 erosions in group II. Initial US had depicted one erosion in group I and four of the 10 erosions in group II. (2) In contrast with conventional radiography, 3D MRI and US demonstrated an increase in erosions in comparison with the initial investigation. (3) The abnormal findings detected by scintigraphy were decreased at the two year follow up. (4) Both groups showed a marked clinical improvement of synovitis and tenosynovitis, as also shown by MRI and US. (5) There was a striking discrepancy between the decrease in the soft tissue lesions as demonstrated by clinical findings, MRI, and US, and the significant increase in erosive bone lesions, which were primarily evident at MRI and US. Conclusions: Despite clinical improvement and a regression of inflammatory soft tissue lesions, erosive bone lesions were increased at the two year follow up, which were more pronounced with 3D MRI and less pronounced with US. The results of our study suggest that owing to the inadequate depiction of erosions and soft tissue lesions, conventional radiography alone has limitations in the intermediate term follow up of treatment. US has a high sensitivity for depicting inflammatory soft tissue lesions, but dynamic 3D MRI is more sensitive in differentiating minute erosions.

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

Objective: To evaluate the interobserver reliability among 14 experts in musculoskeletal ultrasonography (US) and to determine the overall agreement about the US results compared with magnetic resonance imaging (MRI), which served as the imaging “gold standard”. Methods: The clinically dominant joint regions (shoulder, knee, ankle/toe, wrist/finger) of four patients with inflammatory rheumatic diseases were ultrasonographically examined by 14 experts. US results were compared with MRI. Overall agreements, sensitivities, specificities, and interobserver reliabilities were assessed. Results: Taking an agreement in US examination of 10 out of 14 experts into account, the overall κ for all examined joints was 0.76. Calculations for each joint region showed high κ values for the knee (1), moderate values for the shoulder (0.76) and hand/finger (0.59), and low agreement for ankle/toe joints (0.28). κ Values for bone lesions, bursitis, and tendon tears were high (κ = 1). Relatively good agreement for most US findings, compared with MRI, was found for the shoulder (overall agreement 81%, sensitivity 76%, specificity 89%) and knee joint (overall agreement 88%, sensitivity 91%, specificity 88%). Sensitivities were lower for wrist/finger (overall agreement 73%, sensitivity 66%, specificity 88%) and ankle/toe joints (overall agreement 82%, sensitivity 61%, specificity 92%). Conclusion: Interobserver reliabilities, sensitivities, and specificities in comparison with MRI were moderate to good. Further standardisation of US scanning techniques and definitions of different pathological US lesions are necessary to increase the interobserver agreement in musculoskeletal US.

EULAR report on the use of ultrasonography in painful knee osteoarthritis. Part 1: Prevalence of inflammation in osteoarthritis

Objectives: To assess the prevalence of inflammation in subjects with chronic painful knee osteoarthritis (OA), as determined by the presence of synovitis or joint effusion at ultrasonography (US); and to evaluate the correlation between synovitis, effusion, and clinical parameters. Methods: A cross sectional, multicentre, European study was conducted under the umbrella of EULAR-ESCISIT. Subjects had primary chronic knee OA (ACR criteria) with pain during physical activity ⩾30 mm for at least 48 hours. Clinical parameters were collected by a rheumatologist and an US examination of the painful knee was performed by a radiologist or rheumatologist within 72 hours of the clinical examination. Ultrasonographic synovitis was defined as synovial thickness ⩾4 mm and diffuse or nodular appearance, and a joint effusion was defined as effusion depth ⩾4 mm. Results: 600 patients with painful knee OA were analysed. At US 16 (2.7%) had synovitis alone, 85 (14.2%) had both synovitis and effusion, 177 (29.5%) had joint effusion alone, and 322 (53.7%) had no inflammation according to the definitions employed. Multivariate analysis showed that inflammation seen by US correlated statistically with advanced radiographic disease (Kellgren-Lawrence grade ⩾3; odds ratio (OR) = 2.20 and 1.91 for synovitis and joint effusion, respectively), and with clinical signs and symptoms suggestive of an inflammatory “flare”, such as joint effusion on clinical examination (OR = 1.97 and 2.70 for synovitis and joint effusion, respectively) or sudden aggravation of knee pain (OR = 1.77 for joint effusion). Conclusion: US can detect synovial inflammation and effusion in painful knee OA, which correlate significantly with knee synovitis, effusion, and clinical parameters suggestive of an inflammatory “flare”.

Interobserver reliability in musculoskeletal ultrasonography: results from a “Teach the Teachers” rheumatologist course

Objective: To assess the interobserver reliability of the main periarticular and intra-articular ultrasonographic pathologies and to establish the principal disagreements on scanning technique and diagnostic criteria between a group of experts in musculoskeletal ultrasonography. Methods: The shoulder, wrist/hand, ankle/foot, or knee of 24 patients with rheumatic diseases were evaluated by 23 musculoskeletal ultrasound experts from different European countries randomly assigned to six groups. The participants did not reach consensus on scanning method or diagnostic criteria before the investigation. They were unaware of the patients’ clinical and imaging data. The experts from each group undertook a blinded ultrasound examination of the four anatomical regions. The ultrasound investigation included the presence/absence of joint effusion/synovitis, bony cortex abnormalities, tenosynovitis, tendon lesions, bursitis, and power Doppler signal. Afterwards they compared the ultrasound findings and re-examined the patients together while discussing their results. Results: Overall agreements were 91% for joint effusion/synovitis and tendon lesions, 87% for cortical abnormalities, 84% for tenosynovitis, 83.5% for bursitis, and 83% for power Doppler signal; κ values were good for the wrist/hand and knee (0.61 and 0.60) and fair for the shoulder and ankle/foot (0.50 and 0.54). The principal differences in scanning method and diagnostic criteria between experts were related to dynamic examination, definition of tendon lesions, and pathological v physiological fluid within joints, tendon sheaths, and bursae. Conclusions: Musculoskeletal ultrasound has a moderate to good interobserver reliability. Further consensus on standardisation of scanning technique and diagnostic criteria is necessary to improve musculoskeletal ultrasonography reproducibility.

Evaluation of several ultrasonography scoring systems for synovitis and comparison to clinical examination: results from a prospective multicentre study of rheumatoid arthritis

Objectives To evaluate different global ultrasonographic (US) synovitis scoring systems as potential outcome measures of rheumatoid arthritis (RA) according to the Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) filter. Methods To study selected global scoring systems, for the clinical, B mode and power Doppler techniques, the following joints were evaluated: 28 joints (28-joint Disease Activity Score (DAS28)), 20 joints (metacarpophalangeals (MCPs) + metatarsophalangeals (MTPs)) and 38 joints (28 joints + MTPs) using either a binary (yes/no) or a 0–3 grade. The study was a prospective, 4-month duration follow-up of 76 patients with RA requiring anti-tumour necrosis factor (TNF) therapy (complete follow-up data: 66 patients). Intraobserver reliability was evaluated using the intraclass correlation coefficient (ICC), construct validity was evaluated using the Cronbach α test and external validity was evaluated using level of correlation between scoring system and C reactive protein (CRP). Sensitivity to change was evaluated using the standardised response mean. Discriminating capacity was evaluated using the standardised mean differences in patients considered by the doctor as significantly improved or not at the end of the study. Results Different clinimetric properties of various US scoring systems were at least as good as the clinical scores with, for example, intraobserver reliability ranging from 0.61 to 0.97 versus from 0.53 to 0.82, construct validity ranging from 0.76 to 0.89 versus from 0.76 to 0.88, correlation with CRP ranging from 0.28 to 0.34 versus from 0.28 to 0.35 and sensitivity to change ranging from 0.60 to 1.21 versus from 0.96 to 1.36 for US versus clinical scoring systems, respectively. Conclusion This study suggests that US evaluation of synovitis is an outcome measure at least as relevant as physical examination. Further studies are required in order to achieve optimal US scoring systems for monitoring patients with RA in clinical trials and in clinical practice.

Sagittal laser optical tomography for imaging of rheumatoid finger joints.

We present a novel optical tomographic imaging system that was designed to determine two-dimensional spatial distribution of optical properties in a sagittal plane through finger joints. The system incorporates a single laser diode and a single silicon photodetector into a scanning device that records spatially resolved light intensities as they are transmitted through a finger. These data are input to a model-based iterative image reconstruction (MOBIIR) scheme, which uses the equation of radiative transfer (ERT) as a forward model for light propagation through tissue. We have used this system to obtain tomographic images of six proximal interphalangeal finger joints from two patients with rheumatoid arthritis. The optical images were compared to clinical symptoms and ultrasound images.