Evaluation of a novel photo optical imaging (Lightscan) with musculoskeletal ultrasound and clinical examination in the assessment of inflammatory activity in PIP joints in patients with rheumatoid arthritis and osteoarthritis

Doctoral thesis German OPEN
Amitai, Isabella (2016)
  • Publisher: Freie Universität Berlin Universitätsbibliothek, Garystr. 39, 14195 Berlin
  • Subject: 610 Medizin und Gesundheit | 610 Medical sciences; Medicine | musculoskeletal ultrasound | osteoarthritis | photo optical imaging | rheumatoid arthritis | Lightscan
    • ddc: ddc:610
    mesheuropmc: musculoskeletal diseases

Objectives: Lightscan is a novel rapid, low cost and non-invasive imaging technology to assess inflammatory activity in proximal interphalangeal (PIP) joints, which can easily be performed. The results are calculated automatically. This is the first comparative study of photo optical imaging (POI), ‘Lightscan’, with musculoskeletal ultrasonography (US), clinical examination (CE) and DAS28 (only RA) in patients with rheumatoid arthritis (RA), osteoarthritis (OA) and in healthy subjects. Methods: N=696 PIP joints of both hands were examined in n=87 subjects (70 women average age 49±19 years, range 22-86). The total cohort included 38 patients with RA, 21 patients with OA and 28 healthy subjects. For the CE, all PIP joints were examined for swollen or tenderness joints. Each PIP joint was considered separately for synovitis in GSUS and PDUS. Also a semi-quantitative sum-score for the 8 PIP joints in palmar and dorsal view was calculated (range 0-24) as well as a sum-score including all results for palmar and dorsal view (range 0-48) in order to create an US mean sum-score for further comparison to the POI results. The POI examination follows a standardised procedure: The PIP joints were placed and transilluminated one after the other. Examination of one PIP joint takes one minute at most. PIP joints were transilluminated by laser diodes with three different wavelengths (670, 820, and 904 nm). A CCD camera was recording the scattered-light in a 2-dimensional light pattern. A mean sum-score was developed for POI. Results: POI correlated significantly with GSUS (r=0.473, p<0.01) and PDUS (r=0.486, p<0.01). POI did not correlate with DAS28. With US as reference, POI had a sensitivity of 74% and a specificity of 93%. In the ROC-analysis, the Lightscan showed a higher sensitivity and specificity (AUC=0.879) for the distinction of healthy subjects versus patients (OA, RA) than US in greyscale (GSUS; AUC=0.797) and power Doppler (PDUS; AUC=0.67). The agreement rates between POI and GSUS were up to 79%, between POI and PDUS up to 92%, and between POI and CE up to 66%. Conclusion: The Lightscan is a new technology offering sensitive imaging detection of inflammatory changes in subjects with RA and OA. POI was more sensitive than CE and correlated significantly to GSUS and PDUS, while presenting a higher sensitivity and specificity for the detection of healthy subjects versus patients (RA; OA), based on the ROC-analysis. However, further investigations are needed.
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