In vivo monitoring of rashes caused by systemic lupus erythematosus disease using snapshot spectral imaging

Monitoring the activity of systemic lupus erythematosus (SLE) is important to patient management. Blood biochemical indexes are commonly assessed but are both time demanding and traumatizing. In this study, a noninvasive and real-time spatial-spectral data tool was used to monitor SLE patients through rash spectral data. To build the relationship between the rash spectrum changes and changes in the patients' status, a snapshot hyperspectral Fourier transform imaging spectrometer was built to monitor the rash reflectance changes of hospitalized SLE patients. A simple rash activity index (RAI) which was normally distributed with the doctor's visual rating of rash severity was calculated from hyperspectral images. The sensitivity of the change in RAI is higher than complement 3/4 levels. RAI and anti-dsDNA antibodies both decreased as the patients recovered. Anti-dsDNA and complement 3/4 were important indicators of SLE activity suggesting that the RAI directly correlated with patient status. The snapshot spectrometer therefore provides an auxiliary method to monitor SLE disease.