Challenges of automatic processing of large amount of skin lesion multispectral data

2020

This work will describe the challenges involved in setting up automatic processing for a large differentiated data set. In this study, a multispectral (skin diffuse reflection images using 526nm (green), 663nm (red), and 964nm (infrared) illumination and autofluorescence (AF) image using 405 nm excitation) data set with 756 lesions (3024 images) was processed. Previously, using MATLAB software, finding markers, correctly segmenting images with dark edges and image alignment were the main causes of the problems in automatic data processing. To improve automatic processing and eliminate the use of licensed software, the latter was substituted with the open source Python environment. For more …

Skin cancer screening – better safe than sorry

2020

Skin cancer is the most common type of cancers. In Latvia, on average there are approximately 200 new melanoma and 1300 non-melanoma cancer cases per year. Non-melanoma cancers are: Basal Cell Carcinoma, Squamous Cell Carcinoma and others. It is essential to discover skin cancer at an early stage when it is treatable. For this reason, a reliable, non-invasive and quantitative skin cancer screening method is necessary in order to discover skin cancer as early as possible and to help physicians such as general practitioners and dermatologists assign patients to the best treatment as soon as possible. In this article, the current skin cancer incidence as well as the screening situation in Latv…

Spectral imaging as a tool for the evaluation of skin cancer post-operative scars

2020

Skin cancer is the most common type of cancer in the USA and worldwide.1 An early diagnosis is the key to a successful treatment. Among the skin cancers, the malignant melanoma (MM) accounts for 1% of the cases while it is responsible for the majority of deaths. Basal cell carcinoma (BCC) is the most common form of skin cancer with a very low mortality rate.2 Unfortunately, skin cancer recurrence is a common problem for MM and BCC patients. We propose a post-operative scar screening with non-invasive autofluorescence (AF) imaging to detect an early growth of any residual tissue from the cancer removal procedure. The screening images can serve also as a visual evidence for the post-op patien…

Optical design improvement for noncontact skin cancer diagnostic device

2018

Multispectral diffuse reflectance imaging and autofluorescence photo-bleaching imaging are methods that have been investigated for use in skin disorder diagnostics. In response to the ever-increasing incidence of skin cancer in light skinned populations a new device has been designed incorporating both of these methods. The aim of the study was to create a device that is most efficient in terms of hardware and software parameters for the screening of malignant and benign skin lesions. A set of 525 nm, 630 nm and 980 nm LEDs were used to illuminate the skin area at three wavelengths [1] and a set of 405 nm LEDs were used to induce the skin autofluorescence [2]. For a more homogenous illumina…

A method for skin malformation classification by combining multispectral and skin autofluorescence imaging

2018

As the incidence of skin cancer is still increasing worldwide, there is a high demand for early, non-invasive and inexpensive skin lesion diagnostics. In this article we describe and combine two skin imaging methods: skin autofluorescence (AF) and multispectral criterion p’. To develop this method, we used custom made prototype with 405 nm, 526 nm, 663 nm and 964 nm LED illuminations, perpendicular positioned linear polarizers, 515 nm filter and IDS camera. Our aim is to develop a skin lesion diagnostic device for primary care physicians who do not have experience in dermatology or skin oncology. In this study we included such common benign lesion groups as seborrheic keratosis, hyperkerato…

Autofluorescence Imaging of the Skin Is an Objective Non-Invasive Technique for Diagnosing Pseudoxanthoma Elasticum

2021

Pseudoxanthoma elasticum (PXE) is a rare multisystemic autosomal recessive connective tissue disease. In most cases, skin manifestations of PXE are the first to develop, followed later by severe ocular and cardiovascular complications. In our present study, in addition to dermoscopy, we introduced novel techniques, autofluorescence (AF) and diffuse reflectance (DR) imaging for the assessment of affected skin sites of five PXE patients. PXE-affected skin areas in most skin sites showed a previously observed pattern upon dermoscopic examination. With the novel imaging, PXE-affected skin lesions displayed high AF intensity. During our measurements, significantly higher mean, minimum and maximu…

089 Autofluorescence imaging for non-invasive visualization and quantification of skin lesions of patients with pseudoxanthoma elasticum

2021

Imaging of LED-excited autofluorescence photobleaching rates for skin diagnostics

2019

The aim of this study is to develop a novel non-invasive approach for skin cancer (melanoma, basal cell and squamous cell carcinomas) diagnostics by mapping the AF intensity decrease (photo-bleaching) rates under continuous 405 nm LED excitation. For parametric mapping of skin AF intensity decrease rates a sequence of filtered AF imaging under 405 nm LED excitation for 20 seconds at a power density of ~7 mW/cm2 with a frame rate 0.5 fps was recorded and analyzed by cloud-based prototype device. Several clinical cases and potential future applications of the proposed autofluorescence photobleaching rate imaging technique are discussed.

Visualization of Keratin with Diffuse Reflectance and Autofluorescence Imaging and Nonlinear Optical Microscopy in a Rare Keratinopathic Ichthyosis.

2021

Keratins are one of the main fluorophores of the skin. Keratinization disorders can lead to alterations in the optical properties of the skin. We set out to investigate a rare form of keratinopathic ichthyosis caused by KRT1 mutation with two different optical imaging methods. We used a newly developed light emitting diode (LED) based device to analyze autofluorescence signal at 405 nm excitation and diffuse reflectance at 526 nm in vivo. Mean autofluorescence intensity of the hyperkeratotic palmar skin was markedly higher in comparison to the healthy control (162.35 vs. 51.14). To further assess the skin status, we examined samples from affected skin areas ex vivo by nonlinear optical micr…

Differentiation of seborrheic keratosis from basal cell carcinoma, nevi and melanoma by RGB autofluorescence imaging

2018

A clinical trial on the autofluorescence imaging of skin lesions comprising 16 dermatologically confirmed pigmented nevi, 15 seborrheic keratosis, 2 dysplastic nevi, histologically confirmed 17 basal cell carcinomas and 1 melanoma was performed. The autofluorescence spatial properties of the skin lesions were acquired by smartphone RGB camera under 405 nm LED excitation. The diagnostic criterion is based on the calculation of the mean autofluorescence intensity of the examined lesion in the spectral range of 515 nm–700 nm. The proposed methodology is able to differentiate seborrheic keratosis from basal cell carcinoma, pigmented nevi and melanoma. The sensitivity and specificity of the prop…

Simple and convenient remote photoplethysmography system for monitoring regional anesthesia effectiveness

2017

Simple and inexpensive remote photoplethysmography system for monitoring the effectiveness of regional anesthesia was developed and tested. The system involves surgical lamp as light source, compact video camera and computer with custom developed software. Data from eight patients were processed and the effectiveness of regional anesthesia was calculated. The results showed that the standard surgical lamp can be used as a light source together with camera for remote monitoring of regional anesthesia effectiveness.

Evaluation of skin pathologies by RGB autofluorescence imaging

2017

A clinical trial on autofluorescence imaging of malignant and non-malignant skin pathologies comprising 32 basal cell carcinomas (BCC), 4 malignant melanomas (MM), 1 squamous cell carcinoma (SCC), 89 nevi, 14 dysplastic nevi, 20 hemangiomas, 23 seborrheic keratoses, 4 hyperkeratoses, 3 actinic keratoses, 3 psoriasis, 1 dematitis, 2 dermatofibromas, 5 papillofibromas, 12 lupus erythematosus, 7 purpura, 6 bruises, 5 freckles, 3 fungal infections, 1 burn, 1 tattoo, 1 age spot, 1 vitiligo, 32 postoperative scars, 8 post cream therapy BCCs, 4 post radiation therapy scars, 2 post laser therapy scars, 1 post freezing scar as well as 114 reference images of healthy skin was performed. The sequence …

Remote photoplethysmography system for unsupervised monitoring regional anesthesia effectiveness

2017

Determining the level of regional anesthesia (RA) is vitally important to both an anesthesiologist and surgeon, also knowing the RA level can protect the patient and reduce the time of surgery. Normally to detect the level of RA, usually a simple subjective (sensitivity test) and complicated quantitative methods (thermography, neuromyography, etc.) are used, but there is not yet a standardized method for objective RA detection and evaluation. In this study, the advanced remote photoplethysmography imaging (rPPG) system for unsupervised monitoring of human palm RA is demonstrated. The rPPG system comprises compact video camera with green optical filter, surgical lamp as a light source and a …

Determination of chromophore distribution in skin by spectral imaging

2012

Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.

Autofluorescence imaging for recurrence detection in skin cancer postoperative scars

2020

This clinical study is a first attempt to use autofluorescence for recurrence diagnosis of skin cancer in postoperative scars. The proposed diagnostic parameter is based on a reduction in scar autofluorescence, evaluated in the green spectral channel. The validity of the method has been tested on 110 postoperative scars from 56 patients suspected of non-melanoma skin cancer, with eight patients (13 scars) available for the repeated examination. The recurrence diagnosis within a scar has been made after two subsequent autofluorescence check-ups, representing the temporal difference between the scar autofluorescence amplitudes as a vector. The recognition of recurrence has been discussed to r…

Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera

2015

The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.

Non-invasive LED-based screening solution for skin cancer

2019

Skin cancer is the most common type of malignant tumors in humans. Early diagnosis is the key to successful surgical treatment. In this work we present a non-invasive screening tool for early stage detection of skin cancer and also for the evaluation of post-operative scars.

Quantitative Multispectral Imaging Differentiates Melanoma from Seborrheic Keratosis.

2021

Melanoma is a melanocytic tumor that is responsible for the most skin cancer-related deaths. By contrast, seborrheic keratosis (SK) is a very common benign lesion with a clinical picture that may resemble melanoma. We used a multispectral imaging device to distinguish these two entities, with the use of autofluorescence imaging with 405 nm and diffuse reflectance imaging with 525 and 660 narrow-band LED illumination. We analyzed intensity descriptors of the acquired images. These included ratios of intensity values of different channels, standard deviation and minimum/maximum values of intensity of the lesions. The pattern of the lesions was also assessed with the use of particle analysis. …