Histologic examination of skin biopsies is currently the gold standard to definitively diagnose malignant skin lesions; however, biopsies are minor, invasive procedures with potential risks. With the advancement of imaging techniques such as laser speckle contrast imaging (LSCI), it is now possible to evaluate neoplastic skin lesions in real-time and noninvasively. LSCI has been widely used to image surface blood flow in tissues, such as skin, retina, and brain. In this preliminary study, we hypothesized that blood flow within microvessels differs between neoplastic and non-neoplastic skin. This study presents a descriptive demonstration of LSCI application in dermatology. LSCI was utilized to assess surface blood flow in potentially neoplastic skin lesions at our institution’s dermatology clinics. Preliminary data demonstrated decreased contrast within speckle contrast images of malignant and premalignant skin lesions, suggesting increased blood flow to these areas of interest. LSCI may show utility as a noninvasive technique to evaluate neoplastic skin lesions prior to biopsy; however, further systematic optimization is required.
The non-selective beta-blocker timolol has shown promising evidence for healing chronic, recalcitrant wounds, improving scar cosmesis, and expediting the completion of secondary intention. The purpose of our pilot study is to use clinical imaging, two-photon excitement fluorescence (TPF) and second harmonic generation (SHG) microscopy to evaluate the temporal and molecular effects of timolol vs. normal saline in Sprague-Dawley rats traumatized by 5-millimeter dermal punch biopsy. Initial findings suggest timolol delays wound contraction, but advanced imaging techniques may reveal novel collagenous or vascular mechanisms by which timolol is affecting acute wound healing.
Dermatoscopes are commonly utilized by medical professionals for the qualitative visual inspection of skin lesions. While automated image processing techniques and varied illumination strategies can aid in structural analysis of lesions, robust quantification of functional information is largely unknown. To address this knowledge gap, we have developed a compact, handheld dermatoscope that enables real-time blood flow measurements of skin using coherent illumination and laser speckle imaging (LSI). A second color camera attached to the dermatoscope helps with the simultaneous real-time observation of the skin lesions and allows the user to acquire and save color images via a custom Graphical User Interface. In-vitro characterization utilizing a blood flow phantom demonstrated that the dermatoscope is capable of quantifying changes in blood flow across a physiologically relevant range even when used in a handheld manner with ambient lighting. We also demonstrated that the dermatoscope can quantify blood flow in skin lesions in human subjects and that significant differences in blood flow are present among lesion types. There was significantly increased blood flow relative to the surrounding skin in cherry angiomas compared to solar lentigos (p<0.05), which was expected based on the vascular and pigment compositions of the two lesion types. Furthermore, we have compared blood flow maps collected from potentially cancerous lesions prior to histological analysis to determine whether blood flow measurements can help in the diagnosis of benign and malignant skin lesions. Information provided by the LSI dermatoscope may help with earlier and more accurate diagnoses of pigmented skin lesions.
Treatment and management of alopecia are highly determined by an accurate diagnosis, which can be challenging due to the lack of methods to properly visualize hair follicles. Current standard diagnosis is based on dermoscopy for non-scarring alopecia and scalp biopsy for scarring types of alopecia. Dermoscopy can be inconclusive, while biopsy is a painful procedure. In this study, we used a clinical tomograph based on multiphoton microscopy (MPM) to non-invasively image the scalp of 5 healthy subjects and of 12 patients affected by non-scarring alopecia (androgenetic and areata) and scarring alopecia (frontal fibrosing). MPM is capable of non-invasive in vivo imaging of follicular structures in human scalp including hair shafts, hair follicles and sebaceous glands via two-photon excited fluorescence (TPEF) from keratin and NADH/FAD and of the papillary dermis surrounding the hair follicles through second harmonic generation (SHG) from collagen and TPEF from elastin fibers. In normal and non-scarring alopecia patients, MPM often identified presence of sebaceous glands associated with hair follicles, while MPM images of scarring alopecia were characterized by miniaturization of hair follicles as well as by presence of macrophages and lymphocytes surrounding hair follicles. A quantitative analysis involving measurement of hair follicle diameter sizes showed they were significantly smaller in scarring comparing to non-scarring alopecia patients and to normal scalp subjects (p < 0.043). This study shows, in a limited number of patients, that MPM imaging can non-invasively identify morphological features that distinguish scarring from non-scarring alopecia.
A smartphone mobile medical application is presented, that provides analysis of the health of skin on the face using a smartphone image and cloud-based image processing techniques. The mobile application employs the use of the camera to capture a front face image of a subject, after which the captured image is spatially calibrated based on fiducial points such as position of the iris of the eye. A facial recognition algorithm is used to identify features of the human face image, to normalize the image, and to define facial regions of interest (ROI) for acne assessment. We identify acne lesions and classify them into two categories: those that are papules and those that are pustules.
Automated facial acne assessment was validated by performing tests on images of 60 digital human models and 10 real human face images. The application was able to identify 92% of acne lesions within five facial ROIs. The classification accuracy for separating papules from pustules was 98%.
Combined with in-app documentation of treatment, lifestyle factors, and automated facial acne assessment, the app can be used in both cosmetic and clinical dermatology. It allows users to quantitatively self-measure acne severity and treatment efficacy on an ongoing basis to help them manage their chronic facial acne.
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