Differentiation between arthrosis (Art) and psoriatic arthritis (PA) using fluorescence optical imaging

Zielsetzung:

Optical imaging is an alternative to MRI in imaging suspected joint involvement in PA and Art. We investigated whether dynamic indocyanin green (ICG) imaging can provide additional information concerning the distinction between both in clinically affected and unaffected joints.

Material und Methodik:

Image-time series of the hands of 9 patients (Art: n = 5, PA: n = 4, mean age 56,2a, 3 male) were examined by an expert clinician and underwent optical imaging (Xiralite X4, Mivenion, Berlin, Germany) after injection of ICG (Pulsion, Munich, Germany). Images were assessed using an in-house software. ROIs were drawn on clinically affected (n = 46) and unaffected (n = 22) joints by an expert reader. Time-intensity curves were analysed with respect to the following parameters: Maximum intensity (max), time to peak (ttp), area under curve (auc) and rate of early enhancement (ree). Results were assessed by Wilcoxon rank sum test. A p < 0.05 was accepted to demonstrate statistical significance.

Ergebnisse:

Median SI were as follows: max 6425 and 6080; auc 1.8 × 10⁵ and 1.6 × 10⁵; ree 71.4 and 51.5 in affected joints in PA and Art respectively. Ttp was 54 s in both. Median SI in unaffected joints in PA and Art were as follows: max 3165 and 2600; auc 9.5 × 10⁴ and 9.9 × 10⁴; ree 40.1 and 34.7 respectively. Ttp was 105 s vs. 102 s. Shapes of time-intensity-curves were more blunt in Art, but Wilcoxon rank sum tests did not demonstrate statistically significant differences between affected joints in PA and Art, nor between unaffected joints in PA and Art, and in a pooled analysis either.

Schlussfolgerungen:

The applied perfusion parameters failed to differentiate between PA and Art. However, there were visually discernible, subtile differences which were not revealed by our current technical analysis.

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