Three-dimensional and thermal surface imaging produces reliable measures of joint shape and temperature: a potential tool for quantifying arthritisReportar como inadecuado

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Arthritis Research and Therapy

, 10:R10

First Online: 23 January 2008Received: 27 March 2007Revised: 20 June 2007Accepted: 23 January 2008


IntroductionThe assessment of joints with active arthritis is a core component of widely used outcome measures. However, substantial variability exists within and across examiners in assessment of these active joint counts. Swelling and temperature changes, two qualities estimated during active joint counts, are amenable to quantification using noncontact digital imaging technologies. We sought to explore the ability of three dimensional 3D and thermal imaging to reliably measure joint shape and temperature.

MethodsA Minolta 910 Vivid non-contact 3D laser scanner and a Meditherm med2000 Pro Infrared camera were used to create digital representations of wrist and metacarpalphalangeal MCP joints. Specialized software generated 3 quantitative measures for each joint region: 1 Volume; 2 Surface Distribution Index SDI, a marker of joint shape representing the standard deviation of vertical distances from points on the skin surface to a fixed reference plane; 3 Heat Distribution Index HDI, representing the standard error of temperatures. Seven wrists and 6 MCP regions from 5 subjects with arthritis were used to develop and validate 3D image acquisition and processing techniques. HDI values from 18 wrist and 9 MCP regions were obtained from 17 patients with active arthritis and compared to data from 10 wrist and MCP regions from 5 controls. Standard deviation SD, coefficient of variation CV, and intraclass correlation coefficients ICC were calculated for each quantitative measure to establish their reliability. CVs for volume and SDI were <1.3% and ICCs were greater than 0.99.

ResultsThermal measures were less reliable than 3D measures. However, significant differences were observed between control and arthritis HDI values. Two case studies of arthritic joints demonstrated quantifiable changes in swelling and temperature corresponding with changes in symptoms and physical exam findings.

Conclusion3D and thermal imaging provide reliable measures of joint volume, shape, and thermal patterns. Further refinement may lead to the use of these technologies to improve the assessment of disease activity in arthritis.

Abbreviations3D= three-dimensional

ACR= American College of Rheumatology

CV= coefficient of variation

HDI= heat distribution index

ICC= intra-class correlation coefficient

JIA= juvenile idiopathic arthritis

MCP= metacarpalphalangeal

MRI= magnetic resonance imaging

RA= rheumatoid arthritis

RF= rheumatoid factor

ROC= receiver operating characteristic

ROI= region of interest

SD= standard deviation

SDI= surface distribution index.

Electronic supplementary materialThe online version of this article doi:10.1186-ar2360 contains supplementary material, which is available to authorized users.

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Autor: Steven J Spalding - C Kent Kwoh - Robert Boudreau - Joseph Enama - Julie Lunich - Daniel Huber - Louis Denes - Raphael H


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