Bedside Differentiation Between Benign and Malignant Pigmented Skin Tumours by Four Diagnostic Imaging Technologies - A Pilot Study

Structural and functional imaging of psoriasis for severity assessment and quantitative monitoring of treatment response using high-resolution optoacoustic imaging

Psoriasis is a chronic inflammatory skin disease, characterized by thick scaly plaques. It imposes a notable disease burden with varying levels of severity affecting the quality of life significantly. Current disease severity assessment relies on semi-objective visual inspection based on the Psoriasis Area and Severity index (PASI) score that might not be sensitive to sub-clinical changes. Histology of psoriasis skin lesions necessitate invasive skin biopsies. This indicates an unmet need for a non-invasive, objective and quantitative approach to assess disease severity serially. Herein, we employ multispectral Raster-Scanning Optoacoustic Mesoscopy (ms-RSOM) derived structural and microvascular functional imaging metrics to examine the lesional and non-lesional skin in psoriasis subjects across different severities and also evaluate the treatment outcome in a subject with topical steroids and biologics, such as adalimumab. ms-RSOM derived structural metrics like epidermal thickness and total blood volume (TBV) and microvascular functional information such as oxygen saturation (sO2) are evaluated by spectrally resolving the endogenous chromophores like melanin, oxy-, and deoxy-hemoglobin. Initial findings reveal an elevated sO2 and TBV with severity in lesional and non-lesional psoriasis skin, thus representing increasing inflammation. An increase in epidermal thickness is also noted with the degree of severity, corresponding to the inflammation and increased abnormal cell growth. As a marker to evaluate the treatment response, we observed a decrease in epidermal thickness, sO2, and TBV in a psoriasis patient post-treatment, which is consistent with the decrease in the PASI score from 4.1 to 1.9. We envision that ms-RSOM has a huge potential to be translated into routine clinical setting for the diagnosis of severity and assessment of treatment monitoring in psoriasis subjects.

Confocal microscopy and optical coherence tomography of inflammatory skin diseases in hairs and pilosebaceous units: A systematic review

Common skin disorders such as acne vulgaris, rosacea and folliculitis are bothersome prevalent inflammatory diseases of hair follicles that can easily be investigated bedside using optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) with micrometre resolution, opening a novel era for high-resolution hair follicle diagnostics and quantitative treatment evaluation. EMBASE, PubMed and Web of Science were searched until 5 January 2023 to identify all studies imaging hair follicle characteristics by RCM and OCT for diagnosis and monitoring of treatment in hair follicle-based skin disorders. This study followed PRISMA guidelines. After inclusion of articles, methodological quality was assessed using the QUADAS-2 critical appraisal checklist. Thirty-nine in vivo studies (33 RCM and 12 OCT studies) were included. The studies focused on acne vulgaris, rosacea, alopecia areata, hidradenitis suppurativa, folliculitis, folliculitis decalvans, lichen planopilaris, discoid lupus erythemasus, frontal fibrosing alopecia and keratosis pilaris. Inter- and perifollicular morphology including number of demodex mites, hyperkeratinization, inflammation and vascular morphology could be assessed by RCM and OCT in all included skin disorders. Methodological study quality was low, and interstudy outcome variability was high. Quality assessment showed high or unclear risk of bias in 36 studies. Both RCM and OCT visualize quantitative features as size, shape, content and abnormalities of hair follicles, and have potential to support clinical diagnosis and evaluate treatment effects. However, larger studies with better methodological quality are needed to implement RCM and OCT directly into clinical practice.

Research progress on the application of optical coherence tomography in the field of oncology

Optical coherence tomography (OCT) is a non-invasive imaging technique which has become the “gold standard” for diagnosis in the field of ophthalmology. However, in contrast to the eye, nontransparent tissues exhibit a high degree of optical scattering and absorption, resulting in a limited OCT imaging depth. And the progress made in the past decade in OCT technology have made it possible to image nontransparent tissues with high spatial resolution at large (up to 2mm) imaging depth. On the one hand, OCT can be used in a rapid, noninvasive way to detect diseased tissues, organs, blood vessels or glands. On the other hand, it can also identify the optical characteristics of suspicious parts in the early stage of the disease, which is of great significance for the early diagnosis of tumor diseases. Furthermore, OCT imaging has been explored for imaging tumor cells and their dynamics, and for the monitoring of tumor responses to treatments. This review summarizes the recent advances in the OCT area, which application in oncological diagnosis and treatment in different types: (1) superficial tumors:OCT could detect microscopic information on the skin’s surface at high resolution and has been demonstrated to help diagnose common skin cancers; (2) gastrointestinal tumors: OCT can be integrated into small probes and catheters to image the structure of the stomach wall, enabling the diagnosis and differentiation of gastrointestinal tumors and inflammation; (3) deep tumors: with the rapid development of OCT imaging technology, it has shown great potential in the diagnosis of deep tumors such in brain tumors, breast cancer, bladder cancer, and lung cancer.