Bone changes assessed with High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) in early inflammatory arthritis: a 12-month cohort study

ABSTRACTObjectivesWe sought to determine the sensitivity of high resolution peripheral quantitative computed tomography (HR-pQCT) to detect change and identify erosions in comparison with conventional radiography (CR) in early inflammatory arthritis patients. We also explored which prognostic factors contribute to bone damage assessed by HR-pQCT in the first year of diagnosis.Methods46 patients with arthritic symptoms less than one year, and a clinical diagnosis of inflammatory arthritis were prospectively imaged at baseline and 12-months. HR-pQCT scans of the 2nd and 3rd MCP joints and CR of the hands and feet were performed. Joint space width (JSW), total bone mineral density (Tt.BMD), erosion presence and volume were assessed with HR-pQCT. Scan-rescan precision was assessed to define an individual-level least significant change (LSC) criterion. Regression analyses explored prognostic factors for bone damage progression.ResultsWe observed no significant group-level changes in JSW, Tt.BMD or erosion volume. 20% or fewer joints demonstrated individual-level changes greater than the LSC criterion for mean JSW, Tt.BMD and erosion volume. HR-pQCT detected more erosions than CR in the 2nd and 3rd MCP. Increased symptom duration at diagnosis was associated (p < 0.10) with lower JSW minimum and higher JSW standard deviation.ConclusionsWe have demonstrated stability in erosion, bone density and JSW over 12-months in most patients receiving treatment for inflammatory arthritis using a LSC criterion, although patients with longer symptom duration prior to treatment initiation had demonstrable negative effects on JSW estimates. HR-pQCT captures bone damage and progression undetectable by CR in the imaged joints.

Hydrodynamics and bed morphological characteristics around a boulder in a gravel stream

This paper presents experimental studies on hydrodynamics and bed morphological characteristics under varying water and sediment discharges over a gravel channel bed with a boulder. Firstly, flow characteristics over a non-eroded bed with a mild slope were investigated. Results show that along the transect line located one diameter away from the boulder centerline, the existence of the boulder has negligible impact on the mean flow characteristics, which are similar to flows over a flat bed. At the boulder centerline, the flow is largely deflected by the boulder and turbulence characteristics in the horizontal plane are largely enhanced in the wake of the boulder. Secondly, water scour experiments were carried out over a steep slope. It could be observed that scour occurred around the boulder and bedloads were deposited downstream, forming a typical pool–riffle sequence. An analysis shows that the length scale (L/D) of geometric features associated with pool depth, riffle height and pool–riffle distance (S/D) are positively related to the boulder-related Froude number (Frb): L/D = 1.18Frb − 0.11 and S/D = 12.5Frb + 0.6; and the erosion volume (Ve) for flat bed and boulder bed is positively and negatively related to the averaged Froude number (Fr): Ve/D3 = 37.1Fr − 21.3 and Ve/D3 = −44.8Fr − 38.6, where D is the boulder diameter.

Assessing the Reliability of a Semiautomated Segmentation Algorithm for Quantifying Erosions in the Metacarpophalangeal Joints of Patients with Rheumatoid Arthritis

Objective.Assess the reliability of early erosions in rheumatoid arthritis (EERA) software for quantifying erosive damage to the metacarpophalangeal joints of patients with rheumatoid arthritis (RA).Methods.One hundred magnetic resonance image sets from 68 patients with early referral RA were evaluated. Reliability was assessed using 95% limits of agreement and intraclass correlation coefficient (ICC) with 95% CI.Results.Limits of agreement linearly depended on erosion volume: 0.44× between readers and 0.19× within readers. Interrater ICC was 0.976 (95% CI 0.965–0.984) and intrarater ICC was 0.996 (95% CI 0.994–0.997).Conclusion.EERA is highly reproducible for quantifying erosions in patients with early RA.

Erosion Experiment of Self-Excited Oscillation Pulsed Jet

In order to improve the erosion effect of jet under submergence condition, experimental studies of erosion generated from the self-excited pulsed jet was carried out by using developed self-excited oscillation nozzle. The erosion volume and depth of pulsed jet were measured and taking mortar block as an erosion part. The results were that the standoff has significant influence on erosion effect. The erosion volume firstly decreases with increases in cavity length and then increases to a peak value. Erosion volume of pulsed jet is significantly higher than that of continuous jet, the erosion depth of two jet has slight difference.