Shota Ichikawa

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.

Cartilage quantification using contrast-enhanced MRI in the wrist of rheumatoid arthritis: cartilage loss is associated with bone marrow edema

OBJECTIVE To quantify wrist cartilage using contrast MRI and compare with the extent of adjacent synovitis and bone marrow edema (BME) in patients with rheumatoid arthritis (RA). METHODS 18 patients with RA underwent post-contrast fat-suppressed T1weighted coronal imaging. Cartilage area at the centre of the scaphoid-capitate and radius-scaphoid joints was measured by in-house developed software. We defined cartilage as the pixels with signal intensity between two thresholds (lower: 0.4, 0.5 and 0.6 times the muscle signal, upper: 0.9, 1.0, 1.1, 1.2 and 1.3 times the muscle signal). We investigated the association of cartilage loss with synovitis and BME score derived from RA MRI scoring system. RESULTS Cartilage area was correlated with BME score when thresholds were adequately set with lower threshold at 0.6 times the muscle signal and upper threshold at 1.2 times the muscle signal for both SC (rs=-0.469, p < 0.05) and RS (rs=-0.486, p < 0.05) joints, while it showed no significant correlation with synovitis score at any thresholds. CONCLUSION Our software can accurately quantify cartilage in the wrist and BME associated with cartilage loss in patients with RA. Advances in knowledge: Our software can quantify cartilage using conventional MR images of the wrist. BME is associated with cartilage loss in RA patients.

Quantification of hand synovitis in rheumatoid arthritis: Arterial mask subtraction reinforced with mutual information can improve accuracy of pixel-by-pixel time-intensity curve shape analysis in dynamic MRI: Quantification of Hand Synovitis

Synovitis, which is a hallmark of rheumatoid arthritis (RA), needs to be precisely quantified to determine the treatment plan. Time–intensity curve (TIC) shape analysis is an objective assessment method for characterizing the pixels as artery, inflamed synovium, or other tissues using dynamic contrast‐enhanced MRI (DCE‐MRI).

Long-term inhibition of radiographic joint damage by tofacitinib monotherapy in rheumatoid arthritis patients with rapid radiographic progression about eight cases

Abstract Eight rheumatoid arthritis patients with rapid radiographic progression [(RRP) baseline: mean yearly ΔmTSS (mTSS: modified total Sharp score) 16.5, mean yearly Δ joint erosion score 5.4, mean yearly Δjoint space narrowing score 11.1] and inadequate response to non-biological disease-modifying antirheumatic drugs, who had completed a 3-month randomised study A39211040 (the 1040) were retrospectively investigated for the radiographic outcomes after tofacitinib (TOF) monotherapy. The patients used TOF 5 mg twice daily (BID) followed by TOF 10 mg BID over a 48-month long-term extension A39211041 (the 1041) study. Radiographic outcomes in hands and feet measured by mTSS in seven patients improved after 12 months and were sustained for 48 months. However, RRP was still observed in one patient, although yearly progression of mTSS improved. Radiographic outcomes in middle and large joints measured by Larsen score did not deteriorate in six patients during 48 months. Herpes zoster infections occurred 9, 30 and 39 months after 10 mg BID TOF prescription. No severe adverse events were observed during the study.

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.