Assessment of hand trabecular bone texture with high resolution direct digital radiograph in rheumatoid arthritis: a case control study

Dexamethasone Palmitate Encapsulated in Palmitic Acid Modified Human Serum Albumin Nanoparticles for the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint condition characterized by symmetric, erosive synovitis leading to cartilage erosion and significant disability. Macrophages, pivotal in disease progression, release pro-inflammatory factors upon activation. We developed a nanoparticle delivery system (DXP-PSA NPs), based on palmitic acid modified human serum albumin (PSA), to deliver dexamethasone palmitate (DXP) directly to sites of inflammation, enhancing treatment effectiveness and minimizing possible side effects. The system actively targets scavenger receptor-A on activated macrophages, achieving selective accumulation at inflamed joints. In vitro effect and preliminary targeting abilities were investigated on LPS-activated RAW264.7 cells. The in vivo efficacy and safety were evaluated and compared side to side with commercially available lipid emulsion Limethason® in an advanced adjuvant-induced arthritis rat model. DXP-PSA NPs offer a novel approach to RA treatment and presents promising prospects for clinical translation.

Distal phalangeal bone erosions observed by HR-pQCT in patients with psoriatic onycholysis

OBJECTIVES

PsA prevalence among skin psoriasis is ∼30%. Nail psoriasis, especially onycholysis, is present in >70% of PsA and the risk of developing PsA is more than doubled in patients with nail involvement. We hypothesized that onycholysis may be associated with early bone erosions of the DIP joint without harbouring PsA symptoms.

METHODS

We compared tendon thickness, assessed by US, and bone erosions, assessed by high-resolution peripheral quantitative CT, of the DIP joint in patients with psoriatic onycholysis without PsA (ONY) with those in patients with cutaneous psoriasis only (PSO). We used patients with PsA as reference (PsA group), and healthy age-matched controls (CTRL). Differences between groups were assessed by analysis of variance tests followed by post hoc analysis using the Scheffe method.

RESULTS

Mean (s.e.m.) age of the 87 participants (61% males) was 45.2 (1.3) years. The mean extensor tendon thickness was significantly larger in ONY than in PSO patients. In the PsA group, 68% of patients exhibited erosions of three different shapes: V-, Omega- and U-shape. Association with erosions was greater in the ONY group than in the PSO group (frequency: 57 vs 14%; P < 0.001; mean number of erosions: 1.10 (0.35) vs 0.03 (0.03); P < 0.001).

CONCLUSION

Onycholysis was associated with significant enthesopathy and bone erosions in our cohort. These data support the pathogenic role of enthesopathy in PsA. Onycholysis may be considered as a surrogate marker of severity in psoriasis.

TRIAL REGISTRATION

ClinicalTrails.gov, https://clinicaltrials.gov, NCT02813720.

Automated selection of bone texture regions on hand radiographs: Data from the Osteoarthritis Initiative

Manual selection of finger trabecular bone texture regions on hand X-ray images is time-consuming, tedious, and observer-dependent. Therefore, we developed an automated method for the region selection. The method selects square trabecular bone regions of interest above and below the second to fifth distal and proximal interphalangeal joints. Two regions are selected per joint (16 regions per hand). The method consists of four integral parts: (1) segmentation of a radiograph into hand and background, (2) identification of finger regions, (3) localization of center points of heads of distal phalanges and the distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints, and (4) placement of the regions of interest under and above the distal and proximal interphalangeal joints. A gold standard was constructed from regions selected by two observers on 40 hand X-ray images taken from Osteoarthritis Initiative cohort. Datasets of 520 images were generated from the 40 images to study the effects of hand and finger positioning. The accuracy in regions selection and the agreement in calculating five directional fractal parameters were evaluated against the gold standard. The accuracy, agreement, and effects of hand and finger positioning were measured using similarity index (0 for no overlap and 1 for entire overlap) and interclass correlation coefficient as appropriate. A high accuracy in selecting regions (similarity index ≥ 0.79) and a good agreement in fractal parameters (interclass correlation coefficient ≥ 0.58) were achieved. Hand and finger positioning did not affect considerably the region selection (similarity index ≥ 0.70). These results indicate that the method developed selects bone regions on hand X-ray images with accuracy sufficient for fractal analyses of bone texture.

Directional fractal signature methods for trabecular bone texture in hand radiographs: data from the Osteoarthritis Initiative

PURPOSE

To develop directional fractal signature methods for the analysis of trabecular bone (TB) texture in hand radiographs. Problems associated with the small size of hand bones and the orientation of fingers were addressed.

METHODS

An augmented variance orientation transform (AVOT) and a quadrant rotating grid (QRG) methods were developed. The methods calculate fractal signatures (FSs) in different directions. Unlike other methods they have the search region adjusted according to the size of bone region of interest (ROI) to be analyzed and they produce FSs defined with respect to any chosen reference direction, i.e., they work for arbitrary orientation of fingers. Five parameters at scales ranging from 2 to 14 pixels (depending on image size and method) were derived from rose plots of Hurst coefficients, i.e., FS in dominating roughness (FSSta), vertical (FSV) and horizontal (FSH) directions, aspect ratio (StrS), and direction signatures (StdS), respectively. The accuracy in measuring surface roughness and isotropy/anisotropy was evaluated using 3600 isotropic and 800 anisotropic fractal surface images of sizes between 20 × 20 and 64 × 64 pixels. The isotropic surfaces had FDs ranging from 2.1 to 2.9 in steps of 0.1, and the anisotropic surfaces had two dominating directions of 30° and 120°. The methods were used to find differences in hand TB textures between 20 matched pairs of subjects with (cases: approximate Kellgren-Lawrence (KL) grade ≥ 2) and without (controls: approximate KL grade <2) radiographic hand osteoarthritis (OA). The OA Initiative public database was used and 20 × 20 pixel bone ROIs were selected on 5th distal and middle phalanges. The performance of the AVOT and QRG methods was compared against a variance orientation transform (VOT) method developed earlier [M. Wolski, P. Podsiadlo, and G. W. Stachowiak, "Directional fractal signature analysis of trabecular bone: evaluation of different methods to detect early osteoarthritis in knee radiographs," Proc. Inst. Mech. Eng., Part H 223, 211-236 (2009)].

RESULTS

The AVOT method correctly quantified the isotropic and anisotropic surfaces for all image sizes and scales. Values of FSSta were significantly different (P < 0.05) between the isotropic surfaces. Using the VOT and QRG methods no differences were found at large scales for the isotropic surfaces that are smaller than 64 × 64 and 48 × 48 pixels, respectively, and at some scales for the anisotropic surfaces with size 48 × 48 pixels. Compared to controls, using the AVOT and QRG methods the authors found that OA TB textures were less rough (P < 0.05) in the dominating and horizontal directions (i.e., lower FSSta and FSH), rougher in the vertical direction (i.e., higher FSV) and less anisotropic (i.e., higher StrS) than controls. No differences were found using the VOT method.

CONCLUSIONS

The AVOT method is well suited for the analysis of bone texture in hand radiographs and it could be potentially useful for early detection and prediction of hand OA.

Quantitative in vivo HR-pQCT imaging of 3D wrist and metacarpophalangeal joint space width in rheumatoid arthritis

In this technique development study, high-resolution peripheral quantitative computed tomography (HR-pQCT) was applied to non-invasively image and quantify 3D joint space morphology of the wrist and metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA). HR-pQCT imaging (82 μm voxel-size) of the dominant hand was performed in patients with diagnosed rheumatoid arthritis (RA, N = 16, age: 52.6 ± 12.8) and healthy controls (CTRL, N = 7, age: 50.1 ± 15.0). An automated computer algorithm was developed to segment wrist and MCP joint spaces. The 3D distance transformation method was applied to spatially map joint space width, and summarized by the mean joint space width (JSW), minimal and maximal JSW (JSW.MIN, JSW.MAX), asymmetry (JSW.AS), and distribution (JSW.SD)-a measure of joint space heterogeneity. In vivo precision was determined for each measure by calculating the smallest detectable difference (SDD) and root mean square coefficient of variation (RMSCV%) of repeat scans. Qualitatively, HR-pQCT images and pseudo-color JSW maps showed global joint space narrowing, as well as regional and focal abnormalities in RA patients. In patients with radiographic JSN at an MCP, JSW.SD was two-fold greater vs. CTRL (p < 0.01), and JSW.MIN was more than two-fold lower (p < 0.001). Similarly, JSW.SD was significantly greater in the wrist of RA patients vs. CTRL (p < 0.05). In vivo precision was highest for JSW (SDD: 100 μm, RMSCV: 2.1%) while the SDD for JSW.MIN and JSW.SD were 370 and 110 μm, respectively. This study suggests that in vivo quantification of 3D joint space morphology from HR-pQCT, could improve early detection of joint damage in rheumatological diseases.

Computational identification and quantification of trabecular microarchitecture classes by 3-D texture analysis-based clustering

High resolution peripheral quantitative computed tomography (HR-pQCT) permits the non-invasive assessment of cortical and trabecular bone density, geometry, and microarchitecture. Although researchers have developed various post-processing algorithms to quantify HR-pQCT image properties, few of these techniques capture image features beyond global structure-based metrics. While 3D-texture analysis is a key approach in computer vision, it has been utilized only infrequently in HR-pQCT research. Motivated by high isotropic spatial resolution and the information density provided by HR-pQCT scans, we have developed and evaluated a post-processing algorithm that quantifies microarchitecture characteristics via texture features in HR-pQCT scans. During a training phase in which clustering was applied to texture features extracted from each voxel of trabecular bone, three distinct clusters, or trabecular microarchitecture classes (TMACs) were identified. These TMACs represent trabecular bone regions with common texture characteristics. The TMACs were then used to automatically segment the voxels of new data into three regions corresponding to the trained cluster features. Regional trabecular bone texture was described by the histogram of relative trabecular bone volume covered by each cluster. We evaluated the intra-scanner and inter-scanner reproducibility by assessing the precision errors (PE), intra class correlation coefficients (ICC) and Dice coefficients (DC) of the method on 14 ultradistal radius samples scanned on two HR-pQCT systems. DC showed good reproducibility in intra-scanner set-up with a mean of 0.870±0.027 (no unit). Even in the inter-scanner set-up the ICC showed high reproducibility, ranging from 0.814 to 0.964. In a preliminary clinical test application, the TMAC histograms appear to be a good indicator, when differentiating between postmenopausal women with (n=18) and without (n=18) prevalent fragility fractures. In conclusion, we could demonstrate that 3D-texture analysis and feature clustering seems to be a promising new HR-pQCT post-processing tool with good reproducibility, even between two different scanners.

Wnt signaling pathway in rheumatoid arthritis, with special emphasis on the different roles in synovial inflammation and bone remodeling

Rheumatoid arthritis (RA) is a chronic symmetrical autoimmune disease of unknown etiology that affects primarily the diarthrodial joints. Characteristic features of RA pathogenesis are synovial inflammation and proliferation accompanied by cartilage erosion and bone loss. Fibroblast-like synoviocytes (FLS) display an important role in the pathogenesis of RA. Several lines of evidence show that the Wnt signaling pathway significantly participates in the RA pathogenesis. The Wnt proteins are glycoproteins that bind to the Fz receptors on the cell surface, which leads to several important biological functions, such as cell differentiation, embryonic development, limb development and joint formation. Accumulated evidence has suggested that this signaling pathway plays a key role in the FLS activation, bone resorption and joint destruction during RA development. Greater knowledge of the role of the Wnt signaling pathway in RA could improve understanding of the RA pathogenesis and the differences in RA clinical presentation and prognosis. In this review, new advances of the Wnt signaling pathway in RA pathogenesis are discussed, with special emphasis on its different roles in synovial inflammation and bone remodeling. Further studies are needed to reveal the important role of the members of the Wnt signaling pathway in the RA pathogenesis and treatment.

Prospective assessment of bone texture parameters at the hand in rheumatoid arthritis

OBJECTIVE

Fractal bone analysis (Hmean) is a texture parameter reflecting bone microarchitecture. The BMA device (D3A™ Medical Systems, Orléans, France) is a high-resolution X-ray device that allows assessment of bone texture analysis. We aimed to measure Hmean in rheumatoid arthritis patients at the second and third metacarpal bones, at baseline and after 1 year of follow-up, and to assess the relationship of Hmean and rheumatoid arthritis disease parameters.

METHODS

Patients with rheumatoid arthritis according to ACR criteria were included. They were assessed over 1 year, in the context of a prospective study conducted in Maastricht. For this substudy, activity of the disease was assessed by erythrocyte sedimentation rate, C-reactive protein and Disease Activity Score 28 performed at each visit. Radiographic bone damage was assessed using hand and feet radiographs at baseline and on a 1-year basis. The bone texture parameters were evaluated on the second and third metacarpal heads of the left hand using BMA device.

RESULTS

One hundred and sixty-five rheumatoid arthritis patients were included in this study. At baseline, Hmean was negatively correlated with age [r=-0.22 (P=0.013)] and erythrocyte sedimentation rate [r=-0.16 (P=0.039)]. No significant correlation was found between Hmean and Disease Activity Score, disease activity Visual Analog Scale, daily corticosteroid dose and C-reactive protein. There was a significant increase in Hmean of second and third metacarpal bones over 1 year (1.6% and 1.3%, P<0.01) except in patients with local second and third metacarpal bones erosion.

CONCLUSION

The bone texture parameter Hmean is influenced by age, inflammation and local erosions in rheumatoid arthritis.

European guidance for the diagnosis and management of osteoporosis in postmenopausal women

Guidance is provided in a European setting on the assessment and treatment of postmenopausal women at risk of fractures due to osteoporosis.

INTRODUCTION

The International Osteoporosis Foundation and European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis published guidance for the diagnosis and management of osteoporosis in 2008. This manuscript updates these in a European setting.

METHODS

Systematic literature reviews.

RESULTS

The following areas are reviewed: the role of bone mineral density measurement for the diagnosis of osteoporosis and assessment of fracture risk, general and pharmacological management of osteoporosis, monitoring of treatment, assessment of fracture risk, case finding strategies, investigation of patients and health economics of treatment.

CONCLUSIONS

A platform is provided on which specific guidelines can be developed for national use.