Receiver operating characteristic analysis of ultrasound joint inflammation in relation to structural damage and disease activity in rheumatoid arthritis

Thermography at the Elbow Among Patients with Rheumatoid Arthritis: A Comparison with Ultrasound-Detected Joint Inflammation Findings

INTRODUCTION

There is a lack of data on the use of thermography for elbow joint inflammation assessment among patients with rheumatoid arthritis (RA). Hence, we aimed to compare thermography with ultrasonography (a more established imaging modality for joint inflammation assessment) in the assessment of inflammation in the elbows of patients with RA.

METHODS

Standardised minimum (Tmin), maximum (Tmax) and average (Tavg) temperatures at each elbow (medial, lateral, posterior and anterior aspects) were summed to obtain the thermographic parameters MIN, MAX and AVG, respectively. Ultrasound parameters of elbow joint inflammation included total greyscale (TGS) and total power Doppler (TPD) scores. Pearson's correlation coefficient was utilized for correlation analysis between parameters. The relationship between parameters was characterized using simple linear regression.

RESULTS

Sixty elbows were evaluated from 30 patients with RA in this cross-sectional study. Thermographic parameters (MIN, MAX and AVG) showed significant correlation (P < 0.05) with (1) TPD scores at both elbows (correlation coefficient ranging 0.40 to 0.55) and (2) TGS scores at the right elbow (correlation coefficient ranging 0.39 to 0.42). A statistically significant relationship (P values ranging from 0.002 to 0.033) between parameters was demonstrable as follows: (1) MIN, MAX and AVG versus TPD scores (bilateral elbows) and (2) MIN, MAX and AVG versus TGS scores (right elbow).

CONCLUSION

Thermographic temperatures have been demonstrated to correlate with ultrasound-detected joint inflammation at the elbow in patients with RA. The association is more consistently observed with ultrasound PD joint inflammation than its GS counterpart.

Receiver operating characteristic analysis using a novel combined thermal and ultrasound imaging for assessment of disease activity in rheumatoid arthritis

We aim to determine whether combined thermal and ultrasound (CTUS) imaging can identify rheumatoid arthritis (RA) patients with at least moderate disease activity (DAS28 > 3.2). Temperature differences of maximum (T_max), average (T_avg) and minimum (T_min) temperatures from a control temperature at 22 joints (bilateral hands) were summed up to derive the respective MAX, AVG and MIN per patient. MAX (PD), AVG (PD) and MIN (PD) are CTUS results derived by multiplying MAX, AVG and MIN by a factor of 2 when a patient's total ultrasound power Doppler (PD) joint inflammation score > median score, which otherwise remained unchanged. Receiver operating characteristic (ROC) analysis was used to determine whether CTUS imaging can identify patients with DAS28 > 3.2. In this cross-sectional study, 814 joints were imaged among 37 RA patients (mean disease duration, 31 months). CTUS (but not single modality) imaging parameters were all significantly greater comparing patients with DAS28 > 3.2 versus those with DAS28 ≤ 3.2 (all P < 0.01). Area under the ROC curves (AUCs) using cut-off levels of ≥ 94.5, ≥ 64.6 and ≥ 42.3 in identifying patients with DAS28 > 3.2 were 0.73 , 0.76 and 0.76 for MAX (PD), AVG (PD) and MIN (PD), respectively (with sensitivity ranging from 58 to 61% and specificity all 100%). The use of CTUS in detecting a greater severity of joint inflammation among patients with at least moderate disease activity (DAS28 > 3.2) appears promising and will require further validation in independent RA cohorts.

Clinical Application of Ultra-High-Frequency Ultrasound

Musculoskeletal ultrasound involves the study of many superficial targets, especially in the hands, wrists, and feet. Many of these areas are within the first 3 cm of the skin surface and are ideal targets for ultra-high-frequency ultrasound. The high spatial resolution and the superb image quality achievable allow foreseeing a wider use of this novel technique, which has the potential to bring innovation to diagnostic imaging.

Structural damage in rheumatoid arthritis assessed by musculoskeletal ultrasound: A systematic literature review by the Structural Joint Damage Task Force of the OMERACT Ultrasound Working Group

OBJECTIVES

To identify and synthesize the evidence for the use and measurement properties of musculoskeletal ultrasound in assessing structural joint damage in patients with rheumatoid arthritis (RA).

METHODS

A systematic literature search (SLR) of the PubMed, Embase and Cochrane Library was performed. Original articles were included published in English reporting on ultrasound of bone erosion, cartilage damage and the measurement properties of ultrasound according to the OMERACT filter 2.1.

RESULTS

Of the 1.495 identified articles 149 were included in the final review, most of which reported on cross-sectional studies and used the OMERACT definitions for ultrasonographic pathology. Among these, bone erosions were assessed in 139 (93.3%), cartilage damage in 24 (16.1%), enthesophytes in 8 (5.4%), osteophytes in 15 (10.1%) and malalignment and ankylosis in a single (0.9%) study, respectively. Most studies (126/149, 84.6%) assessed the joints of the hands. The overwhelming majority of studies (127/149, 85.2%) assessed structural joint damage bilaterally. Validity, reliability and responsiveness were assessed in 21 (14.1%), 34 (22.8%) and 17 (11.4%) studies, respectively.

CONCLUSION

While the results of this SLR suggest that ultrasound is a sensitive, reliable and feasible tool to detect damage in RA, they also highlight the need for further research and validation. Findings of this SLR will inform the next steps of the OMERACT Ultrasound Working Group in developing an ultrasound score for assessing structural joint damage in patients with RA.