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

Abstract

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.

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

“…While, there was no significant difference in visual assessment between 0, 6, and 12 months. Moreover, in contrast to earlier systems [15][16][17][18], our approach is fully-automatic and the analysis time is 5~10 seconds per joints, which is very short compared to the previous study.…”

“…In a study by Ichikawa et al [15], software assessed the JSN without margin detection using the joint space difference index (JSDI), which was defined as the chronological change in two radiographs using a temporal subtraction technique. Although the software quantified the JSN progression with high accuracy beyond human eyes even by non-expert of imaging analysis, it tends to be more time-consuming than scoring due to manual operations such as image registration and ROI location [16][17][18][19].…”

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

“…Some computer-based methods to measure JSW from hand radiographs have shown to be useful because they were observer-independent and highly sensitive to change in JSN 22–24,43–48 . The software also had high sensitivity and reliability to detect JSN progression in RA patients 26–29 . However, these studies used the conventional method such as SHS or GSS, which is a visual assessment with ordinal score, as the gold standard.…”

“…However, these studies used the conventional method such as SHS or GSS, which is a visual assessment with ordinal score, as the gold standard. Although in a few “proof of concept” studies, performance of the software was directly compared with the conventional method 21,29 , this is the first study to prove the superiority of software over human observers, exclusively utilizing data which had no interval JSW difference determined by human observers. This highly sensitive method might shorten the period of clinical trials especially when the clinical relevance of such subtle radiographic changes which humans cannot recognize in each patient is established.…”

“…In this software, extraction of distal contours in MCP joints is not required because the position of the metacarpal head relative to the phalanx was assessed when superimposing the images based on the phalanx. Previous studies have already demonstrated the high sensitivity and reliability of the software to detect JSN progression in RA patients 26–29 . However, the superiority over human observers of the software in terms of detecting fine JSW differences has not been clearly demonstrated.…”