Performance of computer-based analysis using temporal subtraction to assess joint space narrowing progression in rheumatoid patients

Subtle radiographic progression at 6 months can be detected using automated quantitative software in rheumatoid arthritis while receiving tocilizumab

OBJECTIVES

We investigated whether our in-house software equipped with partial image phase-only correlation (PIPOC) can detect subtle radiographic joint space narrowing (JSN) progression at 6 months and predict JSN progression in rheumatoid arthritis (RA) patients receiving Tocilizumab.

METHODS

The study included 39 RA patients who were treated with Tocilizumab. Radiological progression of the finger joints was evaluated according to the Genant-modified Sharp score (GSS) at 0, 6, and 12 months.

RESULTS

The success rate of the software for joint space width (JSW) measurement was 96.8% (449/464). The 0-12-month JSW change by the software was significantly greater in joints with the 0-6-month PIPOC (+) group than the 0-6-month PIPOC (-) group (P < 0.001). The 0-12-month JSW change by the software was 0-12 month GSS (+) than with 0-12 month GSS (-) (P = 0.02). Here, '(+)' indicates the JSN progression during the follow-up period. Linear regression tests showed significant correlations between the 0-6 month and the 0-12 month PIPOC in the left second and third metacarpophalangeal joints (R2 = 0.554 and 0.420, respectively).

CONCLUSIONS

Our in-house software equipped with PIPOC could predict subsequent JSN progression with only short-term observations.

Application of ImageJ software for quantification of Hand Joint Space Narrowing in Patients with Rheumatoid Arthritis

BACKGROUND

ImageJ software is used to quantify the joint space width (JSW) of hand and wrist in patients with rheumatoid arthritis (RA) as well as in the healthy control group.

METHOD

Forty-one RA patients and 31 healthy controls are included in this study. All of 72 participants underwent digital radiography of the bilateral hand and wrist, then all the images were opened by ImageJ software to measure the width of wrist and hand joint space (total 2160 joints). Joint space narrowing (JSN) was defined if the width was less than the mean - 2SD of the control group.

RESULT

The mean JSW of all sites of wrist and hand joints of RA patients was significantly reduced as compared to those in the control group (p<0.001). There were 37/41 (90.24%) RA patients who had JSN in at least one joint in hand or wrist. In total, 70.89% of joints on the right and 68.46% of joints on the left wrist and hand had JSN.

CONCLUSION

ImageJ software was simple and convenient , which helps rheumatologists quantify the width of joint space for diagnosis and follow-up in RA patients.

Validation of Fully Automatic Quantitative Software for Finger Joint Space Narrowing Progression for Rheumatoid Arthritis Patients

In rheumatoid arthritis (RA), the radiographic progression of joint space narrowing (JSN) is evaluated using visual assessments. However, those methods are complicated and time-consuming. We developed an automatic system that can detect joint locations and compute the joint space difference index (JSDI), which was defined as the chronological change in JSN between two radiographs. The purpose of this study was to establish the validity of the software that automatically evaluates the temporal change of JSN. This study consisted of 39 patients with RA. All patients were treated with tocilizumab and underwent hand radiography (left and right hand separately) at 0, 6, and 12 months. The JSN was evaluated using mTSS (modified Total Sharp Score) by one musculoskeletal radiologist as well as our automatic system. Software measurement showed that JSDI between 0 and 12 months was significantly higher than that between 0 and 6 months (p < 0.01). While, there was no significant difference in mTSS between 0, 6, and 12 months. The group with higher disease activity at 0 months had significantly higher JSDI between 0 and 6 months than that with lower disease activity (p = 0.02). The automatic software can evaluate JSN progression of RA patients in the finger joint on X-ray.

Fully automatic quantitative software for assessment of minute finger joint space narrowing progression on radiographs: evaluation in rheumatoid arthritis patients with long-term sustained clinical low disease activity

PURPOSE

Rheumatoid arthritis (RA) causes joint space narrowing (JSN) as a form of joint destruction. We developed an automatic system that can detect joint locations and compute the joint space difference index (JSDI), which was defined as the chronological change in JSN between two radiographs. This study aims to evaluate the application of "machine vision" for radiographic image of the finger joints.

MATERIALS AND METHODS

Fifteen RA patients with long-term sustained clinical low disease activity were recruited. All patients underwent hand radiography and power Doppler ultrasonography (PDUS). The JSN was evaluated using the Genant-modified Sharp scoring (GSS) method and the automatic system. Synovial vascularity (SV) was assessed quantitatively using ultrasonography.

RESULTS

There were no significant differences in the JSDI between the joints with JSN and those without JSN on GSS (p = 0.052). The JSDI of the joints with SV was significantly higher than those without SV (p = 0.043). The JSDI of the no therapeutic response group was significantly higher than those of the response group (p < 0.001).

CONCLUSION

Our software can automatically evaluate temporal changes of JSN, which might free rheumatologists / radiologists from the burden of scoring hand radiography.

Detection of Fine Radiographic Progression in Finger Joint Space Narrowing Beyond Human Eyes: Phantom Experiment and Clinical Study with Rheumatoid Arthritis Patients

The visual assessment of joint space narrowing (JSN) on radiographs of rheumatoid arthritis (RA) patients such as the Genant-modified Sharp score (GSS) is widely accepted but limited by its subjectivity and insufficient sensitivity. We developed a software application which can assess JSN quantitatively using a temporal subtraction technique for radiographs, in which the chronological change in JSN between two radiographs was defined as the joint space difference index (JSDI). The aim of this study is to prove the superiority of the software in terms of detecting fine radiographic progression in finger JSN over human observers. A micrometer measurement apparatus that can adjust arbitrary joint space width (JSW) in a phantom joint was developed to define true JSW. We compared the smallest detectable changes in JSW between the JSDI and visual assessment using phantom images. In a clinical study, 222 finger joints without interval score change on GSS in 15 RA patients were examined. We compared the JSDI between joints with and without synovial vascularity (SV) on power Doppler ultrasonography during the follow-up period. True JSW difference was correlated with JSDI for JSW differences ranging from 0.10 to 1.00 mm at increments of 0.10 mm (R² = 0.986 and P < 0.001). Rheumatologists were difficult to detect JSW difference of 0.30 mm or less. The JSDI of finger joints with SV was significantly higher than those without SV (P = 0.030). The software can detect fine differences in JSW that are visually unrecognizable.

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.

Radiographic temporal subtraction analysis can detect finger joint space narrowing progression in rheumatoid arthritis with clinical low disease activity

Background Recent papers suggest that finger joints with positive synovial vascularity (SV) assessed by ultrasonography under clinical low disease activity (CLDA) in rheumatoid arthritis (RA) patients may cause joint space narrowing (JSN) progression. Purpose To investigate the performance of a computer-based method by directly comparing with the conventional scoring method in terms of the detectability of JSN progression in hand radiography of RA patients with CLDA. Material and Methods Fifteen RA patients (13 women, 2 men) with long-term sustained CLDA of >2 years were included. Radiological progression of finger joints was measured or scored using the computer-based method which can detect JSN progression between two radiographic images as the joint space difference index (JSDI), as well as the Genant-modified Sharp score (GSS). We also quantitatively assessed SV of these joints using ultrasonography. Results Out of 270 joints, we targeted 259 finger joints after excluding nine damaged joints (four ankylosis, three complete luxation, and two subluxation) and two improved joints according to the GSS results. The JSDI of finger joints with JSN progression was significantly higher than those without JSN progression ( P = 0.018). The JSDI of finger joints with ultrasonographic SV was significantly higher than those without ultrasonographic SV ( P = 0.004). Progression in JSDI showed stronger associations with ultrasonographic SV than progression in GSS (odds ratio [95% confidence interval]: 7.19 [3.37-15.36] versus 5.84 [2.76-12.33]). Conclusion The computer-based method was comparable to the conventional scoring method regarding the detectability of JSN progression in RA patients with CLDA.

A reliability study using computer-based analysis of finger joint space narrowing in rheumatoid arthritis patients

The joint space difference index (JSDI) is a newly developed radiographic index which can quantitatively assess joint space narrowing progression of rheumatoid arthritis (RA) patients by using an image subtraction method on a computer. The aim of this study was to investigate the reliability of this method by non-experts utilizing RA image evaluation. Four non-experts assessed JSDI for radiographic images of 510 metacarpophalangeal joints from 51 RA patients twice with an interval of more than 2 weeks. Two rheumatologists and one radiologist as well as the four non-experts examined the joints by using the Sharp-van der Heijde Scoring (SHS) method. The radiologist and four non-experts repeated the scoring with an interval of more than 2 weeks. We calculated intra-/inter-observer reliability using the intra-class correlation coefficients (ICC) for JSDI and SHS scoring, respectively. The intra-/inter-observer reliabilities for the computer-based method were almost perfect (inter-observer ICC, 0.966-0.983; intra-observer ICC, 0.954-0.996). Contrary to this, intra-/inter-observer reliability for SHS by experts was moderate to almost perfect (inter-observer ICC, 0.556-0.849; intra-observer ICC, 0.589-0.839). The results suggest that our computer-based method has high reliability to detect finger joint space narrowing progression in RA patients.

Radiographic quantifications of joint space narrowing progression by computer-based approach using temporal subtraction in rheumatoid wrist

OBJECTIVE

To investigate the validity of a computer-based method using temporal subtraction in carpal joints of patients with rheumatoid arthritis (RA), which can detect the difference in joint space between two images with the joint space difference index (JSDI).

METHODS

The study consisted of 43 patients with RA (39 females and 4 males) who underwent radiography at baseline and at 1-year follow-up. The joint space narrowing (JSN) of carpal joints on bilateral hand radiographs was assessed by our computer-based method, using the Sharp/van der Heijde method as the standard of reference. We compared the JSDI of joints with JSN progression in the follow-up period with that of those without JSN progression. In addition, we examined whether there is a significant difference in JSDI in terms of laterality or topology of the joint.

RESULTS

The JSDI of joints with JSN progression was significantly higher than that of those without JSN progression (Mann-Whitney U test, p < 0.001). There was no statistically significant difference in the JSDI between the left and right carpal joints, which was analysed for five different joints altogether and each joint separately (Mann-Whitney U test, p > 0.05). There was statistically significant difference in JSDI among different joints (Kruskal-Wallis test, p = 0.003).

CONCLUSION

These results suggest that our computer-based method may be useful to recognize the JSN progression on radiographs of rheumatoid wrists.

ADVANCES IN KNOWLEDGE

The computer-based temporal subtraction method can detect the JSN progression in the wrist, which is the single most commonly involved site in RA.