Ultrasound in dermatology: principles and applications

Objective 18-month Comparison of the Tolerability of 2 Dermal Fillers Formulated with Tri-Hyal Technology

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Background:

The first phase of this study showed that ART FILLER Universal filler (AFU; FILORGA Laboratories) and ART FILLER Fine lines (AFFL) were non-inferior to JUVÉDERM Ultra 3 (Allergan) and FIRST LINES PureSense (Teoxane), respectively. The clinical benefits of AFU and AFFL on nasolabial folds and crow’s feet persisted until at least Day 180. This article reports results from an open-label extension phase that assessed the tolerability and efficacy of AFU and AFFL for up to 18 months based on clinical evaluation and ultrasound high-frequency imaging.

Methods:

Eligible subjects were enrolled at D180 and assessed on D270, D360, and D540. The primary outcome measured was local tolerability. Secondary outcomes measured included: proportion of subjects in whom the severity of nasolabial folds and crow’s feet remained at least 1 point below the baseline measurement (Lemperle scale); general safety; Global Aesthetic Improvement Scale scores by subjects and investigators; wrinkle volumes; and skin thickness by high-frequency ultrasound.

Results:

Adverse events were consistent with the product information and the initial study. No serious adverse events were recorded. In exploratory analyses, wrinkle correction with AFU and AFFL is sustained for at least 18 months: 48.4% and 98.3% of subjects respectively still showed at least a 1-point decrease in the mean Lemperle score compared with the baseline. The benefits were sustained irrespective of whether subjects received additional injections. Modifications in wrinkle volume and skin thickness at D540 were statistically significant compared with the baseline.

Conclusion:

AFU and AFFL were well tolerated and, in exploratory analyses, showed a sustained efficacy for at least 18 months.

High-frequency (22-MHz) ultrasound for assessing the depth of basal cell carcinoma invasion

BACKGROUND

High-frequency ultrasound (HFUS) has been studied in the diagnosis and therapeutic management of basal cell carcinoma (BCC). The accuracy of this method for location of deep margins remains unknown. This study evaluates HFUS for localization of deep surgical margins in BCC.

MATERIALS AND METHODS

Ultrasound images of 83 lesions from 67 patients with clinical and dermoscopic diagnosis of BCC were compared with histopathological findings. Pearson's correlation coefficient was used to assess the relationship between thickness as measured by HFUS and histopathology.

RESULTS

A strong correlation between HFUS and histopathological measurements was identified (r = 0.9744, P < .001). HFUS had sensitivity of 96%, specificity of 84%, and accuracy of 91% for measurement of deep tumor margins. Factors affecting tumor measurement on HFUS include marked basophilic degeneration of collagen, presence of peritumoral hypertrophic glands or hair follicles, fibrosis, and dense inflammatory changes related to the tumor itself or to prior procedures.

CONCLUSION

High-frequency ultrasound was effective in localizing deep tumor margins in BCC. Therefore, we believe that this diagnostic imaging method is important when selecting a therapeutic approach, considering Mohs micrographic surgery, and evaluating the surgical site.

High-frequency ultrasound in the 21st century

The beginnings of skin ultrasound date back to about 50 years ago. However, the dynamic progress of skin ultrasound took place in the last twenty years, when the unprecedented development of computer technologies occurred, which resulted in the popularization of and easier access to modern ultrasound equipment. Skin tests can be performed with both classic scanners equipped with broadband transducers with a minimum frequency of 15 MHz, and specially dedicated skin systems with high-frequency scanners, which are equipped with mechanical transducers with a frequency of 20 MHz to up to 100 MHz. Owing to technologically advanced machines, ultrasonography has proved to be useful in many areas. The aim of this study was to present the current knowledge and possibilities of skin imaging using high-frequency ultrasonography. Te paper discusses technical aspects, types of devices available on the market, as well as methods for the analysis of ultrasound skin images and parameters useful in their interpretation. We also present current applications of skin ultrasound, with particular emphasis on dermatology and aesthetic medicine. In the field of dermatology, we discussed imaging of focal lesions as well as an assessment of pathologically changed skin and treatment monitoring. We also focused on the use of high-frequency ultrasonography in aesthetic medicine and cosmetology. The popularity of this method is constantly growing in these fields, and ultrasound is now used in everyday practice to assess the skin, plan and monitor procedures, as well as to treat potential complications. High-frequency ultrasonography is a highly effective method for skin evaluation, although still underappreciated in may fields. Further research is needed to standardize this modality, as well as to implement training for operators, and to popularize this imaging technique.

The Application of Ultra-High-Frequency Ultrasound in Dermatology and Wound Management

The management of lower extremity wounds is frequently performed by means of clinical examination, representing a challenge for the clinician due to the various conditions that can potentially enter differential diagnosis. Several diagnostic techniques are available in the dermatologist’s arsenal as a support to diagnosis confirmation, including dermoscopy and ultrasonography. Recently, a novel ultrasonographic technique involving the use of ultra-high ultrasound frequencies has entered the scene, and appears a promising tool in the diagnostic workup of skin ulcerative lesions. The focus of this review is to discuss the potential role of ultra-high-frequency ultrasonography in the diagnostic workup of wounds in the light of the current applications of the technique.

Photoacoustic Imaging as a Tool for Assessing Hair Follicular Organization

Follicular unit extraction (FUE) and follicular unit transplantation (FUT) account for 99% of hair transplant procedures. In both cases, it is important for clinicians to characterize follicle density for treatment planning and evaluation. The existing gold-standard is photographic examination. However, this approach is insensitive to subdermal hair and cannot identify follicle orientation. Here, we introduce a fast and non-invasive imaging technique to measure follicle density and angles across regions of varying density. We first showed that hair is a significant source of photoacoustic signal. We then selected regions of low, medium, and high follicle density and showed that photoacoustic imaging can measure the density of follicles even when they are not visible by eye. We performed handheld imaging by sweeping the transducer across the imaging area to generate 3D images via maximum intensity projection. Background signal from the dermis was removed using a skin tracing method. Measurement of follicle density using photoacoustic imaging was highly correlated with photographic determination (R² = 0.96). Finally, we measured subdermal follicular angles-a key parameter influencing transection rates in FUE.

Diagnostics of Melanocytic Skin Tumours by a Combination of Ultrasonic, Dermatoscopic and Spectrophotometric Image Parameters

Dermatoscopy, high-frequency ultrasonography (HFUS) and spectrophotometry are promising quantitative imaging techniques for the investigation and diagnostics of cutaneous melanocytic tumors. In this paper, we propose the hybrid technique and automatic prognostic models by combining the quantitative image parameters of ultrasonic B-scan images, dermatoscopic and spectrophotometric images (melanin, blood and collagen) to increase accuracy in the diagnostics of cutaneous melanoma. The extracted sets of various quantitative parameters and features of dermatoscopic, ultrasonic and spectrometric images were used to develop the four different classification models: logistic regression (LR), linear discriminant analysis (LDA), support vector machine (SVM) and Naive Bayes. The results were compared to the combination of only two techniques out of three. The reliable differentiation between melanocytic naevus and melanoma were achieved by the proposed technique. The accuracy of more than 90% was estimated in the case of LR, LDA and SVM by the proposed method.

A Review of Noninvasive Techniques for Skin Cancer Detection in Dermatology

As a result of increasing melanoma incidence and challenges with clinical and histopathologic evaluation of pigmented lesions, noninvasive techniques to assist in the assessment of skin lesions are highly sought after. This review discusses the methods, benefits, and limitations of adhesive patch biopsy, electrical impedance spectroscopy (EIS), multispectral imaging, high-frequency ultrasonography (HFUS), optical coherence tomography (OCT), and reflectance confocal microscopy (RCM) in the detection of skin cancer. Adhesive patch biopsy provides improved sensitivity and specificity for the detection of melanoma without a trade-off of higher sensitivity for lower specificity seen in other diagnostic tools to aid in skin cancer detection, including EIS and multispectral imaging. EIS and multispectral imaging provide objective information based on computer-assisted diagnosis to assist in the decision to biopsy and/or excise an atypical melanocytic lesion. HFUS may be useful for the determination of skin tumor depth and identification of surgical borders, although further studies are necessary to determine its accuracy in the detection of skin cancer. OCT and RCM provide enhanced resolution of skin tissue and have been applied for improved accuracy in skin cancer diagnosis, as well as monitoring the response of nonsurgical treatments of skin cancers and the determination of tumor margins and recurrences. These novel approaches to skin cancer assessment offer opportunities to dermatologists, but are dependent on the individual dermatologist's comfort, knowledge, and desire to invest in training and implementation of noninvasive techniques. These noninvasive modalities may have a role in the complementary assessment of skin cancers, although histopathologic diagnosis remains the gold standard for the evaluation of skin cancer.

Ultrasound Feature-Based Diagnostic Model Focusing on the "Submarine Sign" for Epidermal Cysts among Superficial Soft Tissue Lesions

Objective

To develop a diagnostic model for superficial soft tissue lesions to differentiate epidermal cyst (EC) from other lesions based on ultrasound (US) features.

Materials and Methods

This retrospective study included 205 patients who had undergone US examinations for superficial soft tissue lesions and subsequent surgical excision. The study population was divided into the derivation set (n = 112) and validation set (n = 93) according to the imaging date. The following US features were analyzed to determine those that could discriminate EC from other lesions: more-than-half-depth involvement of the dermal layer, “submarine sign” (focal projection of the hypoechoic portion to the epidermis), posterior acoustic enhancement, posterior wall enhancement, morphology, shape, echogenicity, vascularity, and perilesional fat change. Using multivariable logistic regression, a diagnostic model was constructed and visualized as a nomogram. The performance of the diagnostic model was assessed by calculating the area under the curve (AUC) of the receiver operating characteristic curve and calibration plot in both the derivation and validation sets.

Results

More-than-half-depth involvement of the dermal layer (odds ratio [OR] = 3.35; p = 0.051), “submarine sign” (OR = 12.2; p < 0.001), and morphology (OR = 5.44; p = 0.002) were features that outweighed the others when diagnosing EC. The diagnostic model based on these features showed good discrimination ability in both the derivation set (AUC = 0.888, 95% confidence interval [95% CI] = 0.825–0.950) and validation set (AUC = 0.902, 95% CI = 0.832–0.972).

Conclusion

More-than-half-depth of involvement of the dermal layer, “submarine sign,” and morphology are relatively better US features than the others for diagnosing EC.

Ultrasound-guided poly-l-lactic acid nodule excision: The importance of the injector ultrasonographic experience

The possibilities for facial and body treatments are wide, but when it comes to treatment for the cervical region, the options are more restricted and among them, the use of poly-l-lactic acid (PLLA) stands out. PLLA is used for collagen biostimulation and improvement of skin turgor with good results; however this procedure is not free of complications, and for the treatment of these, a correct diagnosis is essential. As it is esthetic medicine, the guarantee of results requires that complications are not tolerated, and thus, any resource that enriches the diagnostic and therapeutic arsenal is of great value. The objective of this study is to report the diagnosis of a PLLA nodule with the help of high-frequency ultrasound, establishing a clinical, radiological, and histopathological correlation, in a patient submitted to PLLA injection for esthetic improvement of the cervical region. We present a case in a female patient presenting a nodule in the cervical region after the application of PLLA, where we performed the excision guided by high-frequency ultrasound. Mastering the diagnostic technique with high-frequency ultrasound can play a valuable role in indicating early surgical exeresis, also contributing to complete patient care. It allows the application of the product, monitoring, diagnosis of the complication, and treatment to be carried out dynamically and precisely by the injector.

Assessment of non-invasive techniques and herbal-based products on dermatological physiology and intercellular lipid properties

Skin is the largest external organ of the human body. It acts as a barrier to protect the human body from environmental pollution, mechanical stress, and excessive water loss. The defensive function resides primarily on top of the epidermis layer commonly known as stratum corneum (SC). Human SC consists of three major lipids, namely ceramide, free fatty acid, and cholesterol that comprise approximately 50%, 25%, and 25% of the total lipid mass, respectively. The optimal composition of SC lipids is the vital epidermal barrier function of the skin. On the other hand, skin barrier serves to limit passive water loss from the body, reduces chemical absorption from the environment, and prevents microbial infection. In contrast, epidermal lipids are important to maintain the cell structure, growth and differentiation, cohesion and desquamation as well as formation of a permeability barrier. Multiple non-invasive in vivo approaches were implemented on a regular basis to monitor skin physiological and intercellular lipid properties. The measurement of different parameters such as transepidermal water loss (TEWL), hydration level, skin elasticity, collagen intensity, melanin content, sebum, pH, and tape stripping is essential to evaluate the epidermal barrier function. Novel non-invasive techniques such as tape stripping, ultrasound imaging, and laser confocal microscopy offer higher possibility of accurate and detailed characterisation of skin barrier. To date, these techniques have also been widely used to determine the effects of herbal plants in dermatology. Herbal plants have been traditionally used for ages to treat a variety of skin diseases, as reported by the World Health Organisation (WHO). Their availability, lower cost, and minimal or no side effects have created awareness among society, thus increase the demand for natural sources as the remedy to treat various skin diseases. This paper reviews several non-invasive techniques and evaluations of herbal-based product in dermatology.

Photoacoustic Imaging of Tattoo Inks: Phantom and Clinical Evaluation

Photoacoustic imaging (PAI) is a novel hybrid imaging modality that provides excellent optical contrast with the spatial resolution of ultrasound in vivo. The method is widely being investigated in the clinical setting for diagnostic applications in dermatology. In this report, we illustrate the utility of PAI as a non-invasive tool for imaging tattoos. Ten different samples of commercially available tattoo inks were examined for their optoacoustic properties in vitro. In vivo PAI of an intradermal tattoo on the wrist was performed in a healthy human volunteer. Black/gray, green, violet and blue colored pigments provided higher levels of PA signal compared to white, orange, red and yellow pigments in vitro. PAI provided excellent contrast and enabled accurate delineation of the extent of the tattoo in the dermis. Our results reveal the photoacoustic properties of tattoo inks and demonstrate the potential clinical utility of PAI for intradermal imaging of tattoos. PAI may be useful as a clinical adjunct for objective preoperative evaluation of tattoos and potentially to guide/monitor laser-based tattoo removal procedures.

The use of high-frequency ultrasonography in the assessment of selected female reproductive structures: the vulva, vagina and cervix

Introduction

High-frequency ultrasonography enables visualization the layered structure of the skin and shows the epidermis, dermis, subcutaneous tissue and skin appendages: hair follicles, sebaceous glands, sweat glands and blood vessels. The aim of this study was to apply high-frequency ultrasonography to evaluate the structure of the vulva, vagina and cervix, and to describe their anatomy in ultrasound.

Material and method

The examinations were conducted with the use of high-frequency probes: DermaView 48 MHz and Episcan 50 MHz, by three operators experienced in performing classical ultrasound scans (with 30-, 10- and 9-year experience). The study involved 50 women aged 20–80 years who reported for a periodical gynecological check-up and presented no symptoms within the reproductive system.

Results

In this study, the individual layers of the skin in the area of the mons pubis, labia majora (together with hair follicles and sweat glands) and labia minora were successfully visualized in all the patients. The subepidermal low-echogenicity band was seen in the area of the mons pubic and labia majora in 40 cases. This concerned 100% of women who underwent cosmetic skin treatments. In all the patients, HFUS demonstrated the layered structure of the anterior and posterior vaginal walls, the walls of the urinary bladder and rectum, layers of the vaginal portion of the cervix and the external opening of the cervix.

Conclusions

High-frequency ultrasonography offers new quality of vulvar, vaginal and cervical imaging. It can be used for evaluation of the vulva and vagina, and confirms their layered structure. It also enables accurate measurements of the thickness of the vulvar epidermis and dermis as well as the thickness of the vaginal walls.

Skin Imaging Using Ultrasound Imaging, Optical Coherence Tomography, Confocal Microscopy, and Two-Photon Microscopy in Cutaneous Oncology

With the recognition of dermoscopy as a new medical technology and its available fee assessment in Korea comes an increased interest in imaging-based dermatological diagnosis. For the dermatologist, who treats benign tumors and malignant skin cancers, imaging-based evaluations can assist with determining the surgical method and future follow-up plans. The identification of the tumor's location and the existence of blood vessels can guide safe treatment and enable the use of minimal incisions. The recent development of high-resolution microscopy based on laser reflection has enabled observation of the skin at the cellular level. Despite the limitation of a shallow imaging depth, non-invasive light-based histopathologic examinations are being investigated as a rapid and pain-free process that would be appreciated by patients and feature reduced time from consultation to treatment. In the United States, the current procedural terminology billing code was established for reflectance confocal microscopy in 2016 and has been used for the skin cancer diagnosis ever since. In this review, we introduce the basic concepts and images of ultrasound imaging, optical coherence tomography, confocal microscopy, and two-photon microscopy and discuss how they can be utilized in the field of dermatological oncology.

Combined high-frequency and Doppler ultrasound in early diagnosis of atrophoderma of Pasini and Pierini

Atrophoderma of Pasini and Pierini is a skin disorder affecting dermal collagen and is clinically characterized by well-defined plaques of depressed skin. Histopathological changes are subtle, and in most cases, the diagnosis requires a comparative study with healthy skin from the same anatomical site. High frequency ultrasound is a useful imaging method for diagnosis of atrophic skin changes. A case is presented in which ultrasound can support the clinical and the histopathological diagnosis of atrophoderma of Pasini and Pierini.

Differences in itch and pain behaviors accompanying the irritant and allergic contact dermatitis produced by a contact allergen in mice

Supplemental Digital Content is Available in the Text.

Introduction:

Irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD) are inflammatory skin diseases accompanied by itch and pain. Irritant contact dermatitis is caused by chemical irritants eliciting an innate immune response, whereas ACD is induced by haptens additionally activating an adaptive immune response: After initial exposure (sensitization) to the hapten, a subsequent challenge can lead to a delayed-type hypersensitivity reaction. But, the sensory and inflammatory effects of sensitization (ICD) vs challenge of ACD are insufficiently studied. Therefore, we compared itch- and pain-like behaviors and inflammatory reactions evoked in mice during the sensitization (ICD) vs challenge phase (ACD) of application of the hapten, squaric acid dibutylester (SADBE).

Objectives:

Our aim was to compare itch- and pain-like behaviors and inflammatory reactions evoked in mice during the sensitization (ICD) vs challenge phase (ACD) of application of the hapten, squaric acid dibutylester (SADBE).

Methods:

Mice were sensitized on the abdomen with 1% SADBE (ACD) or vehicle treated (ICD, control). Spontaneous and stimulus-evoked itch- and pain-like behaviors were recorded in mice before and after 3 daily challenges of the cheek with 1% SADBE (ACD, ICD). Cutaneous inflammation was evaluated with clinical scoring, ultrasound imaging, skin thickness, histology, and analyses of selected biomarkers for contact dermatitis, IL-1β, TNF-α, CXCL10, and CXCR3.

Results:

Allergic contact dermatitis vs ICD mice exhibited more spontaneous site-directed scratching (itch) and wiping (pain). Allergic contact dermatitis—but not ICD—mice exhibited allodynia and hyperalgesia to mechanical and heat stimuli. Inflammatory mediators IL-1β and TNF-α were upregulated in both groups as well as the chemokine receptor, CXCR3. CXCL10, a CXCR3 ligand, was upregulated only for ACD. Inflammatory responses were more pronounced in ACD than ICD.

Conclusion:

These findings provide new information for differentiating the behavioral and inflammatory reactions to hapten-induced ICD and ACD.

Imaging techniques in the diagnosis and monitoring of psoriasis

Plaque psoriasis is a chronic, immune-mediated disease, which has a multifactorial etiopathogenesis. Practical non-invasive techniques to monitor plaque psoriasis progression and treatment are necessary. Imaging techniques available for psoriasis assessment may vary in terms of resolution, depth of penetration and visual representation. This review summarizes the current developments in the field of psoriasis non-invasive imaging techniques, such as dermoscopy, conventional ultrasound and high frequency ultrasonography (HFUS), videocapillaroscopy (VC), reflectance confocal microscopy (RCM), optical microangiography (OMAG), laser Doppler imaging (LDI), multiphoton tomography (MPT) and optical coherence tomography (OCT). The aim was to collect and analyze data concerning types, indications, advantages and disadvantages of modern imaging techniques for in vivo psoriasis assessment. We focused on two main methods, videodermoscopy and HFUS, which can be included in daily dermatologists' practice and which may assist in establishing diagnosis, as well as monitoring response to topical and/or systemic therapy of psoriasis. Dermoscopy may be useful for a first evaluation and may offer an understanding of the type and distribution of blood vessels, as well as the color of the scale and the background of the lesion. Videodermoscopy allows magnification and offers a detailed evaluation of the vessel type. The utility of HFUS consists mainly in monitoring therapy response. These methods may be comparable with virtual histopathology.

Optical coherence tomography angiography and photoacoustic imaging in dermatology

Optical coherence tomography angiography (OCTA) is a relatively novel functional extension of the widely accepted ophthalmic imaging tool named optical coherence tomography (OCT). Since OCTA's debut in ophthalmology, researchers have also been trying to expand its translational application in dermatology. The ability of OCTA to resolve microvasculature has shown promising results in imaging skin diseases. Meanwhile, photoacoustic imaging (PAI), which uses laser pulse induced ultrasound waves as the signal, has been studied to differentiate human skin layers and to help in skin disease diagnosis. This perspective article gives a short review of OCTA and PAI in the field of photodermatology. After an introduction to the principles of OCTA and PAI, we describe the most updated results of skin disease imaging using these two optical imaging modalities. We also place emphasis on dual modality imaging combining OCTA and photoacoustic tomography (PAT) for dermatological applications. In the end, the challenges and prospects of these two imaging modalities in dermatology are discussed.

Quantifying Dermatology: Method and Device for User-Independent Ultrasound Measurement of Skin Thickness

A device and technique to acquire and construct 3D ultrasound volumes of the skin of the hand and arm were developed. The Repeated Skin Thickness Measurement (RSTM) Device moves a high frequency ultrasound probe linearly in 3 axes in a water tank and images a submerged arm. These images are combined into an ultrasound volume, the skin layer segmented, and the thickness extracted. One particular application is measuring progression of scleroderma, a skin thickening disease. The current ultrasound-based scleroderma diagnostic processes assess skin thickness based on a single ultrasound image taken by a clinician holding the ultrasound probe, resulting in low measurement repeatability. The imagery that results from the instrumentation and analysis presented here can be used to create quantitative maps of skin thickness, to monitor the progression of skin-thickening diseases, and to observe the structures of tendons, ligaments, and the other soft tissue of the hand.

Ultrasound Biomicroscopy and High-Frequency Ultrasound for Evaluating Extramammary Paget Disease With Pathologic Correlation

OBJECTIVES

The purpose of this study was to investigate the performance of ultrasound biomicroscopy (UBM) and high-frequency ultrasound (HFUS) in the assessment of extramammary Paget disease (EMPD) and to correlate the imaging features with pathologic findings.

METHODS

In this retrospective study, we described the imaging features from UBM and HFUS based on 17 pathologically proven EMPD cases. The performance for visualizing layer involvement by UBM and HFUS was compared. Additionally, we checked the consistency between layer involvement of the lesions on UBM images and the pathologic results. Additionally, blood flow and the status of lymph nodes were investigated with HFUS.

RESULTS

Ultrasound biomicroscopy revealed that all 17 lesions (100%) were hypoechoic and grew in a creeping form. The feature of layer involvement was shown in 10 lesions (58.8%) limited to the epidermis and 6 lesions (35.3%) involving the dermis, and the remaining lesion (5.9%) involved the full skin layers. Layer involvement was clearly displayed by UBM for all lesions (100%) but for only 5 lesions (29.4%) by HFUS (P < .001). Additionally, the layer involvement of 15 lesions (88.2%) on UBM was consistent with the pathologic results (κ = 0.746). High-frequency ultrasound revealed profuse blood flow in most lesions (64.7% [11 of 17]), and 1 case showed inguinal lymph node metastasis.

CONCLUSIONS

Combined use of UBM and HFUS can provide key information on EMPD based on ultrasound features. Comparatively, UBM provides clearer morphologic information, whereas HFUS provides information on lymph node metastasis and blood flow.

Skin cancer: findings and role of high-resolution ultrasound

Currently available high-resolution transducers allow a detailed ultrasound (US) assessment of skin tumors. US complements clinical examination, dermoscopy, and biopsy in the initial differential diagnosis, surgical planning, locoregional staging, and follow-up of patients with skin malignancies. It is important for dermatologists, skin surgeons, and US operators to be aware of the US imaging findings and to recognize the clinical scenarios where imaging is indicated in the management of skin cancer. The purpose of this review article is to address the most common indications for US in skin oncology and to provide a comprehensive guide to the gray-scale and color-Doppler findings in cutaneous malignant tumors.

Microvascular imaging of the skin

Despite our understanding that the microvasculature plays a multifaceted role in the development and progression of various conditions, we know little about the extent of this involvement. A need exists for non-invasive, clinically meaningful imaging modalities capable of elucidating microvascular information to aid in our understanding of disease, and to aid in the diagnosis/monitoring of disease for more patient-specific care. In this review article, a number of imaging techniques are summarized that have been utilized to investigate the microvasculature of skin, along with their advantages, disadvantages and future perspectives in preclinical and clinical settings. These techniques include dermoscopy, capillaroscopy, Doppler sonography, laser Doppler flowmetry (LDF) and perfusion imaging, laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), including its Doppler and dynamic variant and the more recently developed OCT angiography (OCTA), photoacoustic imaging, and spatial frequency domain imaging (SFDI). Attention is largely, but not exclusively, placed on optical imaging modalities that use intrinsic optical signals to contrast the microvasculature. We conclude that whilst each imaging modality has been successful in filling a particular niche, there is no one, all-encompassing modality without inherent flaws. Therefore, the future of cutaneous microvascular imaging may lie in utilizing a multi-modal approach that will counter the disadvantages of individual systems to synergistically augment our imaging capabilities.

Current and Future Perspectives on Skin Tissue Engineering: Key Features of Biomedical Research, Translational Assessment, and Clinical Application

The skin is responsible for several important physiological functions and has enormous clinical significance in wound healing. Tissue engineered substitutes may be used in patients suffering from skin injuries to support regeneration of the epidermis, dermis, or both. Skin substitutes are also gaining traction in the cosmetics and pharmaceutical industries as alternatives to animal models for product testing. Recent biomedical advances, ranging from cellular-level therapies such as mesenchymal stem cell or growth factor delivery, to large-scale biofabrication techniques including 3D printing, have enabled the implementation of unique strategies and novel biomaterials to recapitulate the biological, architectural, and functional complexity of native skin. This progress report highlights some of the latest approaches to skin regeneration and biofabrication using tissue engineering techniques. Current challenges in fabricating multilayered skin are addressed, and perspectives on efforts and strategies to meet those limitations are provided. Commercially available skin substitute technologies are also examined, and strategies to recapitulate native physiology, the role of regulatory agencies in supporting translation, as well as current clinical needs, are reviewed. By considering each of these perspectives while moving from bench to bedside, tissue engineering may be leveraged to create improved skin substitutes for both in vitro testing and clinical applications.

Efficient Frequency-Domain Synthetic Aperture Focusing Techniques for Imaging With a High-Frequency Single-Element Focused Transducer

Synthetic aperture focusing techniques (SAFT) make the spatial resolution of the conventional ultrasound imaging from a single-element focused transducer more uniform in the lateral direction. In this work, two new frequency-domain (FD-SAFT) algorithms are proposed, which are based on the synthetic aperture radar's wavenumber algorithm, and 2-D matched filtering technique for the image reconstruction. The first algorithm is the FD-SAFT virtual source (FD-SAFT-VS) that treats the focus of a focused transducer as a virtual source having a finite size and the diffraction effect in the far-field is taken into consideration in the image reconstruction. The second algorithm is the FD-SAFT deconvolution (FD-SAFT-DE) that uses the simulated point spread function of the imaging system as a matched filter kernel in the image reconstruction. The performance of the proposed algorithms was studied using a series of simulations and experiments, and it was compared with the conventional B-mode and time-domain SAFT (TD-SAFT) imaging techniques. The image quality was analyzed in terms of spatial resolution, sidelobe level, signal-to-noise ratio (SNR), contrast resolution, contrast-to-speckle ratio, and ex vivo image quality. The results showed that the FD-SAFT-VS had the smallest spatial resolution and FD-SAFT-DE had the second smallest spatial resolution. In addition, FD-SAFT-DE had generally the largest SNR. The computation run time of FD-SAFT-VS and FD-SAFT-DE, depending on the image size, was lower by 4 to 174 times and 4 to 189 times, respectively, compared to the TD-SAFT-virtual point source.

Ultrasound as a diagnostic and interventional aid at point-of-care in dermatology clinic: a case report

Ultrasound is currently underutilized in dermatology practice. However, ultrasound provides clinicians with precise and unique information on cutaneous and subcutaneous lesions, while minimizing costs and complications related to more common and invasive diagnostic methods. We report a patient who presented with a tender subcutaneous mass that was diagnosed and treated using point-of-care ultrasound-guidance at the dermatology clinic. Ultrasound revealed features consistent with a ganglion cyst, which was subsequently injected with triamcinolone acetonide under ultrasound-guidance with the resolution of symptoms upon follow-up one month later. Our study demonstrates the utility of ultrasound as an effective, time-efficient diagnostic and interventional aid that can modify dermatology practice.

Reflectance confocal microscopy for diagnosing keratinocyte skin cancers in adults

BACKGROUND

Early accurate detection of all skin cancer types is important to guide appropriate management and improve morbidity and survival. Basal cell carcinoma (BCC) is usually a localised skin cancer but with potential to infiltrate and damage surrounding tissue, whereas cutaneous squamous cell carcinoma (cSCC) and melanoma are higher risk skin cancers with the potential to metastasise and ultimately lead to death. When used in conjunction with clinical or dermoscopic suspicion of malignancy, or both, reflectance confocal microscopy (RCM) may help to identify cancers eligible for non-surgical treatment without the need for a diagnostic biopsy, particularly in people with suspected BCC. Any potential benefit must be balanced against the risk of any misdiagnoses.

OBJECTIVES

To determine the diagnostic accuracy of RCM for the detection of BCC, cSCC, or any skin cancer in adults with any suspicious lesion and lesions that are difficult to diagnose (equivocal); and to compare its accuracy with that of usual practice (visual inspection or dermoscopy, or both).

SEARCH METHODS

We undertook a comprehensive search of the following databases from inception to August 2016: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL; CPCI; Zetoc; Science Citation Index; US National Institutes of Health Ongoing Trials Register; NIHR Clinical Research Network Portfolio Database; and the World Health Organization International Clinical Trials Registry Platform. We studied reference lists and published systematic review articles.

SELECTION CRITERIA

Studies of any design that evaluated the accuracy of RCM alone, or RCM in comparison to visual inspection or dermoscopy, or both, in adults with lesions suspicious for skin cancer compared with a reference standard of either histological confirmation or clinical follow-up, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data using a standardised data extraction and quality assessment form (based on QUADAS-2). We contacted authors of included studies where information related to the target condition or diagnostic threshold were missing. We estimated summary sensitivities and specificities using the bivariate hierarchical model. For computation of likely numbers of true-positive, false-positive, false-negative, and true-negative findings in the 'Summary of findings' tables, we applied summary sensitivity and specificity estimates to lower quartile, median and upper quartiles of the prevalence observed in the study groups. We also investigated the impact of observer experience.

MAIN RESULTS

The review included 10 studies reporting on 11 study cohorts. All 11 cohorts reported data for the detection of BCC, including 2037 lesions (464 with BCC); and four cohorts reported data for the detection of cSCC, including 834 lesions (71 with cSCC). Only one study also reported data for the detection of BCC or cSCC using dermoscopy, limiting comparisons between RCM and dermoscopy. Studies were at high or unclear risk of bias across almost all methodological quality domains, and were of high or unclear concern regarding applicability of the evidence. Selective participant recruitment, unclear blinding of the reference test, and exclusions due to image quality or technical difficulties were observed. It was unclear whether studies were representative of populations eligible for testing with RCM, and test interpretation was often undertaken using images, remotely from the participant and the interpreter blinded to clinical information that would normally be available in practice.Meta-analysis found RCM to be more sensitive but less specific for the detection of BCC in studies of participants with equivocal lesions (sensitivity 94%, 95% confidence interval (CI) 79% to 98%; specificity 85%, 95% CI 72% to 92%; 3 studies) compared to studies that included any suspicious lesion (sensitivity 76%, 95% CI 45% to 92%; specificity 95%, 95% CI 66% to 99%; 4 studies), although CIs were wide. At the median prevalence of disease of 12.5% observed in studies including any suspicious lesion, applying these results to a hypothetical population of 1000 lesions results in 30 BCCs missed with 44 false-positive results (lesions misdiagnosed as BCCs). At the median prevalence of disease of 15% observed in studies of equivocal lesions, nine BCCs would be missed with 128 false-positive results in a population of 1000 lesions. Across both sets of studies, up to 15% of these false-positive lesions were observed to be melanomas mistaken for BCCs. There was some suggestion of higher sensitivities in studies with more experienced observers. Summary sensitivity and specificity could not be estimated for the detection of cSCC due to paucity of data.

AUTHORS' CONCLUSIONS

There is insufficient evidence for the use of RCM for the diagnosis of BCC or cSCC in either population group. A possible role for RCM in clinical practice is as a tool to avoid diagnostic biopsies in lesions with a relatively high clinical suspicion of BCC. The potential for, and consequences of, misclassification of other skin cancers such as melanoma as BCCs requires further research. Importantly, data are lacking that compare RCM to standard clinical practice (with or without dermoscopy).

High-frequency ultrasound for diagnosing skin cancer in adults

BACKGROUND

Early, accurate detection of all skin cancer types is essential to guide appropriate management and to improve morbidity and survival. Melanoma and squamous cell carcinoma (SCC) are high-risk skin cancers with the potential to metastasise and ultimately lead to death, whereas basal cell carcinoma (BCC) is usually localised, with potential to infiltrate and damage surrounding tissue. Anxiety around missing early curable cases needs to be balanced against inappropriate referral and unnecessary excision of benign lesions. Ultrasound is a non-invasive imaging technique that relies on the measurement of sound wave reflections from the tissues of the body. At lower frequencies, the deeper structures of the body such as the internal organs can be visualised, while high-frequency ultrasound (HFUS) with transducer frequencies of 20 MHz or more has a much lower depth of tissue penetration but produces a higher resolution image of tissues and structures closer to the skin surface. Used in conjunction with clinical and/or dermoscopic examination of suspected skin cancer, HFUS may offer additional diagnostic information compared to other technologies.

OBJECTIVES

To assess the diagnostic accuracy of HFUS to assist in the diagnosis of a) cutaneous invasive melanoma and atypical intraepidermal melanocytic variants, b) cutaneous squamous cell carcinoma (cSCC), and c) basal cell carcinoma (BCC) in adults.

SEARCH METHODS

We undertook a comprehensive search of the following databases from inception up to August 2016: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL; CPCI; Zetoc; Science Citation Index; US National Institutes of Health Ongoing Trials Register; NIHR Clinical Research Network Portfolio Database; and the World Health Organization International Clinical Trials Registry Platform. We studied reference lists as well as published systematic review articles.

SELECTION CRITERIA

Studies evaluating HFUS (20 MHz or more) in adults with lesions suspicious for melanoma, cSCC or BCC versus a reference standard of histological confirmation or clinical follow-up.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted all data using a standardised data extraction and quality assessment form (based on QUADAS-2). Due to scarcity of data and the poor quality of studies, we did not undertake a meta-analysis for this review. For illustrative purposes, we plot estimates of sensitivity and specificity on coupled forest plots.

MAIN RESULTS

We included six studies, providing 29 datasets: 20 for diagnosis of melanoma (1125 lesions and 242 melanomas) and 9 for diagnosis of BCC (993 lesions and 119 BCCs). We did not identify any data relating to the diagnosis of cSCC.Studies were generally poorly reported, limiting judgements of methodological quality. Half the studies did not set out to establish test accuracy, and all should be considered preliminary evaluations of the potential usefulness of HFUS. There were particularly high concerns for applicability of findings due to selective study populations and data-driven thresholds for test positivity. Studies reporting qualitative assessments of HFUS images excluded up to 22% of lesions (including some melanomas) due to lack of visualisation in the test.Derived sensitivities for qualitative HFUS characteristics were at least 83% (95% CI 75% to 90%) for the detection of melanoma; the combination of three features (lesions appearing hypoechoic, homogenous and well defined) demonstrating 100% sensitivity in two studies (lower limits of the 95% CIs were 94% and 82%), with variable corresponding specificities of 33% (95% CI 20% to 48%) and 73% (95% CI 57% to 85%), respectively. Quantitative measurement of HFUS outputs in two studies enabled decision thresholds to be set to achieve 100% sensitivity; specificities were 93% (95% CI 77% to 99%) and 65% (95% CI 51% to 76%). It was not possible to make summary statements regarding HFUS accuracy for the diagnosis of BCC due to highly variable sensitivities and specificities.

AUTHORS' CONCLUSIONS

Insufficient data are available on the potential value of HFUS in the diagnosis of melanoma or BCC. Given the between-study heterogeneity, unclear to low methodological quality and limited volume of evidence, we cannot draw any implications for practice. The main value of the preliminary studies included may be in providing guidance on the possible components of new diagnostic rules for diagnosis of melanoma or BCC using HFUS that will require future evaluation. A prospective evaluation of HFUS added to visual inspection and dermoscopy alone in a standard healthcare setting, with a clearly defined and representative population of participants, would be required for a full and proper evaluation of accuracy.

Eco-Friendly Highly Sensitive Transducers Based on a New KNN-NTK-FM Lead-Free Piezoelectric Ceramic for High-Frequency Biomedical Ultrasonic Imaging Applications

High-frequency ultrasonic imaging with improved spatial resolution has gained increasing attention in the field of biomedical imaging. Sensitivity of transducers plays a pivotal role in determining ultrasonic image quality. Conventional ultrasonic transducers are mostly made from lead-based piezoelectric materials that may be harmful to the human body and the environment. In this study, a new (K,Na)NbO₃-KTiNbO₅-BaZrO₃-Fe₂O₃-MgO (KNN-NTK-FM) lead-free piezoelectric ceramic was utilized in developing eco-friendly transducers for high-frequency biomedical ultrasonic imaging applications. A needle transducer with a small active aperture size of 0.45 × 0.55 mm² was designed and evaluated. The fabricated transducer exhibits great performance with a high center frequency (52.6 MHz), a good electromechanical coupling (k_eff ∼ 0.45), a large bandwidth (64.4% at -6 dB), and a very low two-way insertion loss (10.1 dB). Such high sensitivity is superior to those transducers based on other lead-free piezoelectric materials and can even be comparable to the lead-based ones. Imaging performance of the KNN-NTK-FM needle transducer was analyzed by imaging a wire phantom and an agar tissue-mimicking phantom. Imaging capabilities of the transducer were further demonstrated by ex vivo imaging studies on a porcine eyeball and a rabbit aorta. The results suggest that the KNN-NTK-FM piezoceramic has many attractive properties over other lead-free piezoelectric materials in developing eco-friendly highly sensitive transducers for high-frequency biomedical ultrasonic imaging applications.

Use of platelet-rich plasma to facilitate wound healing

Platelet-rich plasma (PRP) is widely used nowadays in different fields of medicine, affecting physiological processes including tissue regeneration. The use of PRP in maxillofacial surgical interventions and its efficiency in the improvement of postoperative wound healing were analysed. Patients undergoing plastic and reconstructive surgeries in the maxillofacial region were recruited: 50 patients were enrolled into a control group (received no PPRP injection) and 50 patients were enrolled into a treatment group, where PRP was applied during the surgical procedure. Evaluation of treatment outcomes was carried out by determination of IL-1β, TNFα, and IL-6 cytokines levels in the wound-drain fluid. The stages of wound healing were assessed by cytological analyses and ultrasound within a month period. The use of the PRP has substantially positive effects, contributing to the improvement of the healing process. In the treatment group, fibroblasts, macrophages, and collagen fibres appeared and their quantities increased earlier than when compared with control group patients. The concentration of IL-1β and TNFα in wound fluid on day 1 and day 5 after operation was higher for the treatment group as opposed to the control group, which was linked to the influence of PRP on inflammatory and granulation phases of the healing process. An ultrasound examination showed less oedema and infiltration in the tissues around the wound of the treatment group.

Determination of Normal Skin Elasticity by Using Real-time Shear Wave Elastography

OBJECTIVES

To define the reference ranges of normal skin elasticity measurements associated with shear wave elastography (SWE) in healthy volunteers and analyze the factors that may affect SWE.

METHODS

Mean skin thickness and elastic modulus values from 90 healthy volunteers were evaluated with B-mode ultrasonography and SWE in the right fingers and forearms, anterior chest, and abdominal walls. Reference ranges of normal skin elasticity were calculated by using lower and upper limits at the 2.5th and 97.5th percentiles. To investigate the effects of potential factors (site, sex, age, body mass index, and skin thickness) on skin elasticity measurements, a 1-way analysis of variance, the Student t test, and the Pearson correlation test were performed.

RESULTS

Skin elasticity was significantly different at different sites (P < .05). Mean elastic modulus values were 30.3 kPa for the finger, 14.8 kPa for the forearm, 17.8 kPa for the chest wall, and 9.5 kPa for the abdominal wall, and reference ranges of normal skin elasticity were 12.1 to 48.4kPa for the finger, 3.5 to 26.0 kPa for the forearm, 6.6 to 28.9 kPa for the chest wall, and 3.5 to 15.5 kPa for the abdominal wall. Our study revealed that men had higher skin elasticity measurements than women (P < .05), and they were more elevated in participants aged 20 to 50 years than in the other groups at the finger (P < .05). The body mass index and skin thickness had a negligible impact on skin elasticity measurements (P > .05).

CONCLUSIONS

This study revealed that the site, sex, and age should be taken into account when determining the reference ranges of normal skin elasticity by skin elasticity measurements.

Ultrasonic Patterns of Benign Skin Formations

Objective: to reveal ultrasonic features of of epithelial, dermal and vascular benign skin formations. Materials and methods. An ultrasonic study of 50 acantholytic nevuses, 50 acrochordons and 30 hemangiomas, which have an unambiguous clinical and dermatoscopic pattern and do not require differential diagnosis, was carried out. For the comparative evaluation of ultrasonic thickness and density of skin the ratio of scan indices in the lesion area relative to the indices in the adjacent healthy area of the skin was introduced. Results. On the scans of acantholytic nevus the formations that rose above the skin surface, with a nonuniform thickened, hyperechoic epidermis were visualized, in which hypoechoic round-shaped patches occur. A hypoechoic acoustic shadow was determined under the epidermis. On the scans of acrochordons the formations on a narrow base, which were located above the skin surface were visualized. In the region of formations, a discontinuous contour of epidermis with predominantly hyperechogenic areas was determined. Within the formations, the structure of the dermis is heterogeneous with the alternation of normoechoic and hypoechoic areas. Beneath the formation an epidermis structurally similar to the healthy skin epidermis is determined on the level of skin surface under which hypoechoic zone is visualized, which is an acoustic shadow. On the scans of hemangiomas the formations were visualized that rose above the skin surface, with a distinct lateral delimitation from the surrounding tissues. In the area of formations, the epidermis is non-uniformly thickened than healthy skin, hyperechoic round-shaped areas are visualized. Non-uniformly hypoechoic irregulary-shaped regions were determined in the dermis. Conclusion. All examined formations differ from healthy skin by increasing the thickness of the epidermis and dermis, as well as strengthening the overall acoustic solidity of the epidermis and decreasing the acoustic solidity of the dermis. The introduction of the ratio into practice makes it possible to quantify these changes. Moreover, each formation has a peculiar ultrasonic characteristic, allowing the use of pattern analysis for differential diagnosis between epithelial, dermal and vascular forms of benign skin formations.

Imaging in cutaneous surgery

Skin cancer is the most commonly diagnosed cancer in the USA. Mohs micrographic surgery is a microscopically controlled surgical technique that excises lateral and deep surgical margins while also sparing function and achieving a good cosmetic outcome. Given the increasing incidence in skin cancer worldwide and its associated treatment costs, techniques are being developed to improve the time and cost efficacy of this procedure. The use of noninvasive imaging, both in vivo and ex vivo, has the potential to increase efficiency of diagnosis and surgical management of skin cancers. These devices are useful in delineating lateral and deep tumor margins prior to surgery in vivo as well as to detect residual tumor ex vivo virtually in real time.

High-Frequency Ultrasound in Blistering Skin Diseases: A Useful Method for Differentiating Blister Locations

Bullous pemphigoid and pemphigus vulgaris, which belong to the group of subepidermal and intraepidermal bullae, respectively, are two potentially devastating blistering skin diseases. We used high-frequency ultrasound (US) in 3 cases of these diseases as prototypes to study the value of high-frequency US in discriminating blister locations. Our findings showed that high-frequency US has a strong correlation with histomorphometric findings because of its high resolution, and we hope that it will be helpful for differentiating blister locations.

High-frequency ultrasonography (HFUS) as a useful tool in differentiating between plaque morphea and extragenital lichen sclerosus lesions

INTRODUCTION

Morphea and lichen sclerosus (LS) are chronic inflammatory diseases that may pose a diagnostic challenge for a physician. High-frequency ultrasonography (HFUS) is a versatile diagnostic method utilized in dermatologic practice, allowing monitoring the course of the disease, treatment response and differentiation between certain skin disorders.

AIM

To prove the usefulness of HFUS in differentiating between plaque morphea and extragenital LS lesions.

MATERIAL AND METHODS

We examined 16 patients with plaque morphea and 4 patients with extragenital LS using 20 MHz taberna pro medicumTM (Germany) device.

RESULTS

Investigations revealed hyperechogenic entrance echo in both morphea and LS lesions, whereas a distinct polycyclic surface of the entrance echo was detected exclusively in LS.

CONCLUSIONS

High-frequency ultrasonography is a current diagnostic modality that may prove useful in differentiating between morphea and LS lesions.

Formulation and evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid

Background and aims

The main aims of the present study were to formulate an anti-age cream based on vegetal ingredients and ferulic acid and to evaluate the physical characteristics and the efficacy of the cream.

Methods

The active ingredients were Centella asiatica oil, Spilanthes acmella oil, Zingiber officinale extract and ferulic acid. Formulation 1 (F1) was prepared using glyceryl stearate and Ceteareth-25® as emulsifiers and Formulation 2 (F2) using glyceryl stearate and potassium cetyl phosphate, all other ingredients remaining the same. The physical characterization of the creams was performed and the following parameters were analyzed: viscosity, oil droplet size, polydispersity index; also, texture analysis was performed. The anti-aging effect of the F2 was evaluated by assessing the cutaneous density before and after cream application using DUB-cutis® scanner.

Results

The mean diameter of oil drops was 10.26±4.72 mm (F1) and 22.72±7.93 mm (F2) and the polydispersity index was 35.4% and 45.7%, respectively. The mean values for consistency were 594.7±10.3 g (F1) and 300.5±14.5 g (F2), the average values for adhesion were 15.61±0.8 mJ (F1) and 22.25±4.3 mJ (F2), for firmness were 51.2±0.8 g (F1) and 30.3±4.3 g (F2) and the spreadability had values between 72.63 mm2 (F1) and 73.3 mm2 (F2). In vivo study revealed that the mean values of the cutaneous density increased from 9.21±1.39 % to 12.50±1.44 % after 8 weeks of cream application. The herbal ingredients incorporated in the O/W cream base for the antioxidant activity and anti-wrinkle effect, induced changes of the cutaneous density, an important parameter which quantifies the regeneration process of the skin.

Conclusions

An anti-age cream containing herbal active ingredients and ferulic acid with appropriate physical characteristics was obtained. In vivo study of clinical efficacy revealed a positive effect on skin density, which increased after 8 weeks of cream application.

High frequency ultrasound with color Doppler in dermatology

Ultrasonography is a method of imaging that classically is used in dermatology to study changes in the hypoderma, as nodules and infectious and inflammatory processes. The introduction of high frequency and resolution equipments enabled the observation of superficial structures, allowing differentiation between skin layers and providing details for the analysis of the skin and its appendages. This paper aims to review the basic principles of high frequency ultrasound and its applications in different areas of dermatology.

Detection theory for accurate and non-invasive skin cancer diagnosis using dynamic thermal imaging

Skin cancer is the most common cancer in the United States with over 3.5M annual cases. Presently, visual inspection by a dermatologist has good sensitivity (> 90%) but poor specificity (< 10%), especially for melanoma, which leads to a high number of unnecessary biopsies. Here we use dynamic thermal imaging (DTI) to demonstrate a rapid, accurate and non-invasive imaging system for detection of skin cancer. In DTI, the lesion is cooled down and the thermal recovery is recorded using infrared imaging. The thermal recovery curves of the suspected lesions are then utilized in the context of continuous-time detection theory in order to define an optimal statistical decision rule such that the sensitivity of the algorithm is guaranteed to be at a maximum for every prescribed false-alarm probability. The proposed methodology was tested in a pilot study including 140 human subjects demonstrating a sensitivity in excess of 99% for a prescribed specificity in excess of 99% for detection of skin cancer. To the best of our knowledge, this is the highest reported accuracy for any non-invasive skin cancer diagnosis method.