Handheld spatial frequency domain imager for noninvasive Sjögren's syndrome labial salivary gland biopsy

Abstract

A labial salivary gland biopsy (LSGB) plays an essential role in diagnosing Sjögren's syndrome (SS), but its clinical application is limited due to its invasiveness. Here, we present a handheld single snapshot multiple-frequency demodulation-spatial frequency domain imaging (SSMD-SFDI) device for a rapid optical biopsy of labial salivary glands noninvasively. The structural and physiological parameters of lower lip mucosa were obtained from the light reflectance of the layered oral mucosa. The recovered parameters were found to correlate strongly with the progression of SS. In our pilot study on 15 healthy subjects and 183 SS patients, a support vector machine (SVM) classifier using the measured parameters distinguished healthy subjects, LSGB I, II, III, and IV patients in sequence with AUCs of 0.979, 0.898, 0.906, and 0.978, respectively. Critical structural and physiological alterations in the mucosa due to SS were further identified and used to assess its risk using an explainable neural network. The handheld spatial frequency domain imager may serve as a valuable label-free and noninvasive tool for early diagnosing and surveying SS.

Multi-frequency spatial frequency domain imaging: a depth-resolved optical scattering model to isolate scattering contrast in thin layers of skin

“…Optical techniques are already widely utilized in clinical practice, where they are used for determining blood perfusion and blood oxygen saturation, [7][8][9] detecting cancer, 10,11 and optimizing photodynamic therapy, 12,13 among other applications. 14,15 Spatial frequency domain imaging (SFDI) is an optical imaging technique that makes use of structured light illumination to quantitatively measure the absorption (μ a ) and reduced scattering (μ 0 s ) coefficients in tissue and separate their effects by making use of the frequency-specific response of the tissue. 16 The absorption of light contains information about the concentration of molecules that are capable of absorbing photons (e.g., melanin, haemoglobin, etc.…”

“…They satisfy most of the prerequisites that we want from an ideal wound healing assessment method: from the way that light interacts with tissue, it is possible to quantitatively measure concentrations of biological chromophores and indirectly obtain structural information on a microscopic scale, over a large field of view. Optical techniques are already widely utilized in clinical practice, where they are used for determining blood perfusion and blood oxygen saturation, 7 – 9 detecting cancer, 10 , 11 and optimizing photodynamic therapy, 12 , 13 among other applications 14 , 15 …”

“…Optical techniques are already widely utilized in clinical practice, where they are used for determining blood perfusion and blood oxygen saturation, 7 – 9 detecting cancer, 10 , 11 and optimizing photodynamic therapy, 12 , 13 among other applications. 14 , 15 …”