シガケン ナガハマシ ホウゲン ノ ソザイ タイグウ ケイシキ ニ カンスル キジュツテキ ケンキュウ

The isomerization of n-hexadecane over Pt–WO3 catalysts supported on TiO2–SiO2 synthesized by glycothermal reaction with various Si/Ti molar ratios was examined. The catalyst performance depended on Si/Ti molar ratio and WO3 loading. The characterization of the catalysts by XRD, XAFS, UV-vis and so on revealed that with increasing the WO3 loading, the structure of surface W species changed from monomeric species to polytungstate species, which is considered to significantly affect the isomerization selectivity of the catalysts

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

Objective: To investigate the validity of a computerbased 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 0.05). There was statistically significant difference in JSDI among different joints (Kruskal-Wallis test, p = 0.003). Conclusion: These results suggest that our computerbased 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

Quantitative knee cartilage measurement at MR imaging of patients with anterior cruciate ligament tear

In previous studies, numerous approaches were proposed that assess knee cartilage volume quantitatively using 3D magnetic resonance (MR) imaging. However, the clinical use of these approaches is limited because 3D MR is prone to metal artifacts in postoperative cases. Our purpose in this study was to validate a method for knee cartilage volume quantification using conventional MR imaging in patients who underwent anterior cruciate ligament (ACL) reconstruction surgery. The study included 16 patients who underwent MR imaging before and 1 year after ACL reconstruction surgery. Knee cartilage volumes were measured by our computer- based method with the use of T1-weighted sagittal images. We classified the cartilage into eight regions and made comparisons between preoperative and postoperative cartilage volumes in each region. There was a significant difference between preoperative and postoperative cartilage volumes with regard to medial posterior weight-bearing, medial posterior, lateral posterior weight-bearing, and lateral posterior portions (p = 0.006, 0.023, 0.017 and 0.002, respectively). These results were consistent with the previous studies showing that knee cartilage loss occurs frequently in these portions due to an anterior subluxation of the tibia accompanied by ACL tear. With our method, knee cartilage volumes could be measured quantitatively with conventional MR imaging in patients who underwent ACL reconstruction surgery

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

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 T-1 weighted 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 (r(s)=-0.469, p < 0.05) and RS (r(s)= -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

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

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

Background: 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). Purpose/Hypothesis: To assess the feasibility of our original arterial mask subtraction method (AMSM) with mutual information (MI) for quantification of synovitis in RA. Study Type: Prospective study. Subjects: Ten RA patients (nine women and one man; mean age, 56.8 years; range, 38-67 years). Field Strength/Sequence: 3T/DCE-MRI. Assessment: After optimization of TIC shape analysis to the hand region, a combination of TIC shape analysis and AMSM was applied to synovial quantification. The MI between pre-and postcontrast images was utilized to determine the arterial mask phase objectively, which was compared with human subjective selection. The volume of objectively measured synovitis by software was compared with that of manual outlining by an experienced radiologist. Simple TIC shape analysis and TIC shape analysis combined with AMSM were compared in slices without synovitis according to subjective evaluation. Statistical Tests: Pearson's correlation coefficient, paired t-test and intraclass correlation coefficient (ICC). Results: TIC shape analysis was successfully optimized in the hand region with a correlation coefficient of 0.725 (P< 0.01) with the results of manual assessment regarded as ground truth. Objective selection utilizing MI had substantial agreement (ICC50.734) with subjective selection. Correlation of synovial volumetry in combination with TIC shape analysis and AMSM with manual assessment was excellent (r50.922, P< 0.01). In addition, negative predictive ability in slices without synovitis pixels was significantly increased (P< 0.01). Data Conclusions: The combination of TIC shape analysis and image subtraction reinforced with MI can accurately quantify synovitis of RA in the hand by eliminating arterial pixels. Level of Evidence: 2 Technical Efficacy: Stage