Reproducibility and influence of hand rotation on computer-aided joint space analysis

The relationship between structural analysis of the hand and clinical characteristics in psoriatic arthritis

Up to now, there is only limited information available on a possible relationship between clinical characteristics and the mineralization of metacarpal bones and finger joint space distance (JSD) in patients with psoriatic arthritis (PsA). Computerized digital imaging techniques like digital X-ray radiogrammetry (DXR) and computer-aided joint space analysis (CAJSA) have significantly improved the structural analysis of hand radiographs and facilitate the recognition of radiographic damage. The objective of this study was to evaluate clinical features which potentially influence periarticular mineralization of the metacarpal bones and finger JSD in PsA-patients. 201 patients with PsA underwent computerized measurements of the metacarpal bone mineral density (BMD) with DXR and JSD of all finger joints by CAJSA. DXR-BMD and JSD were compared with clinical features such as age and sex, disease duration, C-reactive protein (CRP) as well as treatment with prednisone and disease-modifying antirheumatic drugs (DMARDs). A longer disease duration and an elevated CRP value were associated with a significant reduction of DXR-BMD, whereas JSD-parameters were not affected by both parameters. DXR-BMD was significantly reduced in the prednisone group (-0.0383 g/cm²), but prednisone showed no impact on finger JSD. Patients under the treatment with bDMARDs presented significant lower DXR-BMD (-0.380 g/cm²), JSD_MCP (-0.0179 cm), and JSD_PIP (-0.0121 cm) values. Metacarpal BMD was influenced by inflammatory activity, prednisone use, and DMARDs. In contrast, finger JSD showed only a change compared to baseline therapy. Therefore, metacarpal BMD as well as finger JSD represent radiographic destruction under different aspects.

Sind röntgenologische Scoring-Methoden als Parameter zur Verlaufsbeurteilung der rheumatoiden Arthritis noch zeitgemäß?

Die radiologische Progression beschreibt das Ausmaß der Gelenkzerstörung im Verlauf einer rheumatoiden Arthritis. Zur Quantifizierung der radiologischen Progression werden Scoring-Methoden (z. B. van der Heijde Modifikation des Sharp-Score) eingesetzt. In verschiedenen Studien zu biologischen- bzw. target-synthetischen Disease Modifying Anti-Rheumatic Drugs gelang nur unzureichend eine Differenzierung der radiologischen Progression. Zudem finden die Scores oft keinen routinemäßigen Einsatz in der klinischen Entscheidungsfindung. Durch die computerbasierte Analyse von Handröntgenaufnahmen ist eine valide Quantifizierung der radiologischen Progression und die zuverlässige Bewertung von Therapieeffekten möglich. Somit stellen die computerbasierten Methoden eine vielversprechende Alternative in der Quantifizierung der radiologischen Progression dar.

Radiographic remission in rheumatoid arthritis quantified by computer-aided joint space analysis (CASJA): a post hoc analysis of the RAPID 1 trial

Background

The reduction of finger joint space width (JSW) in patients with rheumatoid arthritis (RA) is strongly associated with joint destruction. Treatment with certolizumab pegol (CZP), a PEGylated anti-TNF, has been proven to be effective in RA patients. The computer-aided joint space analysis (CAJSA) provides the semiautomated measurement of joint space width at the metacarpal-phalangeal joints (MCP) based on hand radiographs. The aim of this post hoc analysis of the RAPID 1 trial was to quantify MCP joint space distance (JSD-MCP) measured by CAJSA between baseline and week 52 in RA patients treated with certolizumab pegol (CZP) plus methotrexate (MTX) compared with MTX/placebo.

Methods

Three hundred twenty-eight patients were included in the post hoc analysis and received placebo plus MTX, CZP 200 mg plus MTX and CZP 400 mg plus MTX. All patients underwent X-rays of the hand at baseline and week 52 as well as assessment of finger joint space narrowing of the MCP using CAJSA (Version 1.3.6; Sectra; Sweden). The joint space width (JSW) was expressed as mean joint space distance of the MCP joints I to V (JSD-MCP_total).

Results

The MTX group showed a significant reduction of joint space of − 4.8% (JSD-MCP_total), whereas in patients treated with CZP 200 mg/MTX and CZP 400 mg/MTX a non-significant change (JSD-MCP_total + 0.6%) was observed. Over 52 weeks, participants with DAS28 remission (DAS28 ≤ 2.6) exhibited a significant joint space increase of + 3.3% (CZP 200 mg plus MTX) and + 3.9% (CZP pegol 400 mg plus MTX).

Conclusion

CZP plus MTX did not reduce JSD-MCP_total estimated by CAJSA compared with MTX/placebo. Furthermore, clinical remission (DAS28 ≤ 2.6) in patients treated with CZP plus MTX was associated with an increasing JSD, indicating radiographic remission in RA.

Computer-Based Radiographic Quantification of Joint Space Narrowing Progression Using Sequential Hand Radiographs: Validation Study in Rheumatoid Arthritis Patients from Multiple Institutions

We have developed a refined computer-based method to detect joint space narrowing (JSN) progression with the joint space narrowing progression index (JSNPI) by superimposing sequential hand radiographs. The purpose of this study is to assess the validity of a computer-based method using images obtained from multiple institutions in rheumatoid arthritis (RA) patients. Sequential hand radiographs of 42 patients (37 females and 5 males) with RA from two institutions were analyzed by a computer-based method and visual scoring systems as a standard of reference. The JSNPI above the smallest detectable difference (SDD) defined JSN progression on the joint level. The sensitivity and specificity of the computer-based method for JSN progression was calculated using the SDD and a receiver operating characteristic (ROC) curve. Out of 314 metacarpophalangeal joints, 34 joints progressed based on the SDD, while 11 joints widened. Twenty-one joints progressed in the computer-based method, 11 joints in the scoring systems, and 13 joints in both methods. Based on the SDD, we found lower sensitivity and higher specificity with 54.2 and 92.8%, respectively. At the most discriminant cutoff point according to the ROC curve, the sensitivity and specificity was 70.8 and 81.7%, respectively. The proposed computer-based method provides quantitative measurement of JSN progression using sequential hand radiographs and may be a useful tool in follow-up assessment of joint damage in RA patients.

Automatic Quantification of Radiographic Wrist Joint Space Width of Patients With Rheumatoid Arthritis

Objective: Wrist joint space narrowing is a main radiographic outcome of rheumatoid arthritis (RA). Yet, automatic radiographic wrist joint space width (JSW) quantification for RA patients has not been widely investigated. The aim of this paper is to present an automatic method to quantify the JSW of three wrist joints that are least affected by bone overlapping and are frequently involved in RA. These joints are located around the scaphoid bone, viz. the multangular-navicular, capitate-navicular-lunate, and radiocarpal joints. Methods: The joint space around the scaphoid bone is detected by using consecutive searches of separate path segments, where each segment location aids in constraining the subsequent one. For joint margin delineation, first the boundary not affected by X-ray projection is extracted, followed by a backtrace process to obtain the actual joint margin. The accuracy of the quantified JSW is evaluated by comparison with the manually obtained ground truth. Results: Two of the 50 radiographs used for evaluation of the method did not yield a correct path through all three wrist joints. The delineated joint margins of the remaining 48 radiographs were used for JSW quantification. It was found that 90% of the joints had a JSW deviating less than 20% from the mean JSW of manual indications, with the mean JSW error less than 10%. Conclusion: The proposed method is able to automatically quantify the JSW of radiographic wrist joints reliably.

SIGNIFICANCE

The proposed method may aid clinical researchers to study the progression of wrist joint damage in RA studies.Objective: Wrist joint space narrowing is a main radiographic outcome of rheumatoid arthritis (RA). Yet, automatic radiographic wrist joint space width (JSW) quantification for RA patients has not been widely investigated. The aim of this paper is to present an automatic method to quantify the JSW of three wrist joints that are least affected by bone overlapping and are frequently involved in RA. These joints are located around the scaphoid bone, viz. the multangular-navicular, capitate-navicular-lunate, and radiocarpal joints. Methods: The joint space around the scaphoid bone is detected by using consecutive searches of separate path segments, where each segment location aids in constraining the subsequent one. For joint margin delineation, first the boundary not affected by X-ray projection is extracted, followed by a backtrace process to obtain the actual joint margin. The accuracy of the quantified JSW is evaluated by comparison with the manually obtained ground truth. Results: Two of the 50 radiographs used for evaluation of the method did not yield a correct path through all three wrist joints. The delineated joint margins of the remaining 48 radiographs were used for JSW quantification. It was found that 90% of the joints had a JSW deviating less than 20% from the mean JSW of manual indications, with the mean JSW error less than 10%. Conclusion: The proposed method is able to automatically quantify the JSW of radiographic wrist joints reliably.

SIGNIFICANCE

The proposed method may aid clinical researchers to study the progression of wrist joint damage in RA studies.

Fully automated joint space width measurement and digital X-ray radiogrammetry in early RA

Objectives

To study fully automated digital joint space width (JSW) and bone mineral density (BMD) in relation to a conventional radiographic scoring method in early rheumatoid arthritis (eRA).

Methods

Radiographs scored by the modified Sharp van der Heijde score (SHS) in patients with eRA were acquired from the SWEdish FarmacOTherapy study. Fully automated JSW measurements of bilateral metacarpals 2, 3 and 4 were compared with the joint space narrowing (JSN) score in SHS. Multilevel mixed model statistics were applied to calculate the significance of the association between ΔJSW and ΔBMD over 1 year, and the JSW differences between damaged and undamaged joints as evaluated by the JSN.

Results

Based on 576 joints of 96 patients with eRA, a significant reduction from baseline to 1 year was observed in the JSW from 1.69 (±0.19) mm to 1.66 (±0.19) mm (p<0.01), and BMD from 0.583 (±0.068) g/cm² to 0.566 (±0.074) g/cm² (p<0.01). A significant positive association was observed between ΔJSW and ΔBMD over 1 year (p<0.0001). On an individual joint level, JSWs of undamaged (JSN=0) joints were wider than damaged (JSN>0) joints: 1.68 mm (95% CI 1.70 to 1.67) vs 1.54 mm (95% CI 1.63 to 1.46). Similarly the unadjusted multilevel model showed significant differences in JSW between undamaged (1.68 mm (95% CI 1.72 to 1.64)) and damaged joints (1.63 mm (95% CI 1.68 to 1.58)) (p=0.0048). This difference remained significant in the adjusted model: 1.66 mm (95% CI 1.70 to 1.61) vs 1.62 mm (95% CI 1.68 to 1.56) (p=0.042).

Conclusions

To measure the JSW with this fully automated digital tool may be useful as a quick and observer-independent application for evaluating cartilage damage in eRA.

Trial registration number

NCT00764725.

Joint damage in rheumatoid arthritis: assessment of a new scoring method

INTRODUCTION

The aim of this study was to assess a novel approach for the quantification of finger joint space narrowing and joint destruction in patients with rheumatoid arthritis (RA) focusing on the peripheral hand articulations.

METHODS

A total of 280 patients with verified RA underwent computerized semi-automated measurements of joint space distance at the finger articulations based on radiographs. The Z-Score, which can differentiate between joint space alterations caused by RA versus age/gender-related changes, was calculated as a comparative parameter. The severity of joint space narrowing was also quantified by the Sharp Score. Sensitivity and specificity of the Z-Score (based on joint space widths differentiated for each peripheral finger joint) were evaluated to reveal the potential for the occurrence of erosions. Additionally, the potential of the Z-Score regarding the differentiation of therapeutic effects on joint space widths in patients under a therapy of methotrexate versus leflunomide was performed.

RESULTS

The Z-Scores of finger articulations in patients with RA were generally decreased. Metacarpal-phalangeal (MCP) joint articulations showed a continuous significant decline of -1.65±0.30 standard deviations dependent on the Sharp Score. The proximal-interphalangeal joints also revealed a significant reduction of the Z-Score (-0.96±0.31 standard deviations). The sensitivity and specificity of MCP joint space distance for the detection of erosions were 85.4% versus 55.2%. The Sharp Score for joint space narrowing was not able to detect different treatments, whereas an accentuated stabilization of joint space narrowing could be identified for the Z-Score of the MCP joints in patients treated with leflunomide and methotrexate.

CONCLUSION

The Z-Scoring method based on computer-aided analysis of joint space widths was able to reliably quantify severity-dependent joint space narrowing in RA patients. In the future, calculation of a Z-Score based on gender-specific and age-specific reference data shows the potential for a surrogate marker of RA progression that comprehends the early identification of patients with RA, and in particular those with erosive course of the disease, enabling a timely therapeutic strategy for cartilage protection.

The usefulness of computer-aided joint space analysis in the assessment of rheumatoid arthritis

OBJECTIVE

Computer-aided joint space analysis (CAJSA) is a newly developed technique for the measurement of radiogeometrically detectable joint space widths of the metacarpal-phalangeal (JSD-MCP) and proximal-interphalangeal articulations (JSD-PIP). The aim of this study was to verify the sensitivity and specificity of these CAJSA measurements in the assessment of established RA.

METHODS

Four hundred and fifty-eight participants (248 healthy subjects, 210 RA patients) underwent computerized semi-automated measurements of the JSD-MCP and JSD-PIP articulations (CAJSA, Radiogrammetry Kit, Version 1.3.6) based on digitally performed radiographs. The Sharp joint space narrowing score was also performed to determine RA-related joint space narrowing.

RESULTS

The significant severity-dependent reduction for JSD-MCP was -44.0% and for JSD-PIP, -25.94% between Sharp scores 0 and 3. The sensitivity and specificity of JSD-MCP (total) was 88.1% versus 77.8%, respectively (AUC = 0.920; P < 0.001). Furthermore, JSD-PIP (total) revealed a lower sensitivity and specificity with 61.4% and 88.7% (AUC = 0.878; P < 0.001).

CONCLUSION

The CAJSA method presented a reliable assessment of disease-related joint space narrowing in patients suffering from RA with excellent sensitivity and specificity. By providing quantitative data, other scoring methods could be significantly improved, and thereby the accuracy of the diagnosis and a better therapeutic evaluation could be achieved.