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

Fully automatic software for detecting radiographic joint space narrowing progression in rheumatoid arthritis : phantom study and comparison with visual assessment

Purpose We have developed an in-house software equipped with partial image phase-only correlation (PIPOC) which can automatically quantify radiographic joint space narrowing (JSN) progression. The purpose of this study was to evaluate the software in phantom and clinical assessments. Materials and methods In the phantom assessment, the software's performance on radiographic images was compared to the joint space width (JSW) difference using a micrometer as ground truth. A phantom simulating a finger joint was scanned underwater. In the clinical assessment, 15 RA patients were included. The software measured the radiological progression of the finger joints between baseline and the 52nd week. The cases were also evaluated with the Genant-modified Sharp score (GSS), a conventional visual scoring method. We also quantitatively assessed these joints' synovial vascularity (SV) on power Doppler ultrasonography (0, 8, 20 and 52 weeks). Results In the phantom assessment, the PIPOC software could detect changes in JSN with a smallest detectable difference of 0.044 mm at 0.1 mm intervals. In the clinical assessment, the JSW change of the joints with GSS progression detected by the software was significantly greater than those without GSS progression (p = 0.004). The JSW change of joints with positive SV at baseline was significantly higher than those with negative SV (p = 0.024). Conclusion Our in-house software equipped with PIPOC can automatically and quantitatively detect slight radiographic changes of JSW in clinically inactive RA patients

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

Fully automatic software for detecting radiographic joint space narrowing progression in rheumatoid arthritis : phantom study and comparison with visual assessment

Purpose We have developed an in-house software equipped with partial image phase-only correlation (PIPOC) which can automatically quantify radiographic joint space narrowing (JSN) progression. The purpose of this study was to evaluate the software in phantom and clinical assessments. Materials and methods In the phantom assessment, the software's performance on radiographic images was compared to the joint space width (JSW) difference using a micrometer as ground truth. A phantom simulating a finger joint was scanned underwater. In the clinical assessment, 15 RA patients were included. The software measured the radiological progression of the finger joints between baseline and the 52nd week. The cases were also evaluated with the Genant-modified Sharp score (GSS), a conventional visual scoring method. We also quantitatively assessed these joints' synovial vascularity (SV) on power Doppler ultrasonography (0, 8, 20 and 52 weeks). Results In the phantom assessment, the PIPOC software could detect changes in JSN with a smallest detectable difference of 0.044 mm at 0.1 mm intervals. In the clinical assessment, the JSW change of the joints with GSS progression detected by the software was significantly greater than those without GSS progression (p = 0.004). The JSW change of joints with positive SV at baseline was significantly higher than those with negative SV (p = 0.024). Conclusion Our in-house software equipped with PIPOC can automatically and quantitatively detect slight radiographic changes of JSW in clinically inactive RA patients

Geological background of the Kairei and Edmond hydrothermal fields along the Central Indian Ridge : Implications for the distinct chemistry between their vent fluids

Hydrogen-rich hydrothermal areas, such as those in the Indian Ocean, may have had an influence on early evolution of life on Earth and thus have attracted interest because they may be a proxy for ancient ecosystems. The Kairei and Edmond hydrothermal fields in the Indian Ocean are separated by 160 km, but exhibit distinct fluid chemistry: Kairei fluids are hydrogen-rich; Edmond fluids are hydrogen-poor. At this region, the Central Indian Ridge shows an intermediate spreading rate, 48 mm year−1 as full rate, where the hydrothemal fields occur. Kairei field vent fluids show persistently high concentrations of H2. The Kairei field seems to be unique among hydrogen-enriched hydrothermal regions: most similar hydrogen-rich hydrothermal activity occurs along slowly spreading ridge, <40 mm year−1. The geological and tectonic aspects of the Kairei and Edmond hydrothermal fields were studied to try to elucidate geological constraints on hydrogen production. Visual observations of the seafloor near Kairei from a submersible revealed olivine-rich plutonic rocks with olivine gabbro-troctolite-dunite assemblages exposed within 15 km of the vent field, with serpentinized ultramafic mantle rocks on the Oceanic Core Complex (OCC). The OCC area might be a recharge zone of Kairei hydrothermal activity producing H2-rich vent fluids. The chaotic seafloor within 30 km of the Kairei field reflects a magma-starved condition persisting there for 1 Myr. Asymmetric geomagnetic and gravity anomalies near the Kairei field can be used to infer that patchy olivine-rich intrusions are scattered within mantle ultramafics, where infiltrated seawater reacts with magma and ultramafic rocks or olivine-rich rocks. The heterogeneous uppermost lithosphere containing shallow olivine-rich rock facies surrounding the Kairei field provides abundant H2 into the vent fluid through serpentinization. The hydrogen-rich Kairei field is hosted by basalt, with mafic-ultramafic olivine-rich lithology; the ordinary, hydrogen-poor Edmond field is hosted by a normal basaltic lithology. The contrasting geochemical signatures of the two fields reported here can also be found in ancient rocks from a juvenile Earth. This suggests that lithology-controlled generation of hydrogen may have operated for a long time and be relevant to the origin of life on Earth

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 (R-2 = 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