According to a study published in Arthritis Research & Therapy, poor to fair correlation was found between Fluorescence optical imaging (FOI) enhancement and MRI- and ultrasound (US)-detected synovitis in patients suffering from hand osteoarthritis (OA). FOI was unsuccessful in identifying synovitis in the thumb base.

FOI exhibits improved microcirculation in finger joints as an indication of inflammation. Øystein Maugesten et al. investigated the validity and diagnostic performance of FOI measuring synovitis in persons with hand OA and it was compared with the MRI- and US-detected synovitis.

A total of 221 patients with hand OA underwent FOI and US (gray-scale synovitis and power Doppler activity) of the bilateral hands and contrast-enhanced MRI analysis of the dominant hand. For all modalities, 15 joints in every hand were calculated on semi-quantitative scales (grade 0 to 3). All in all, 4 FOI images were assessed: 1 composite image (Prima Vista Mode (PVM)) and 3 images demonstrating stages of fluorescent dye distribution. Spearman’s correlation coefficients were deliberated between sum scores of FOI, MRI, and US. Using MRI or US as reference, the sensitivity, specificity, and area under the curve (AUC) were estimated for FOI.

FOI synovitis sum scores displayed poor to fair correlations with MRI and GS scores. No FOI image exhibited both good sensitivity and specificity. FOI exhibited similar diagnostic performance with PD activity and GS synovitis as reference.

‘The poor outcomes in this may be attributed to low-grade inflammation with less vascularization,’ concluded the study researchers.