Usefulness of High-Frequency Ultrasound in the Classification of Histologic Subtypes of Primary Basal Cell Carcinoma

Preliminary Clinical Experience with a Novel Optical–Ultrasound Imaging Device on Various Skin Lesions

A compact handheld skin ultrasound imaging device has been developed that uses co-registered optical and ultrasound imaging to provide diagnostic information about the full skin depth. The aim of the current work is to present the preliminary clinical results of this device. Using additional photographic, dermoscopic and ultrasonic images as reference, the images from the device were assessed in terms of the detectability of the main skin layer boundaries and characteristic image features. Combined optical-ultrasonic recordings of various types of skin lesions (melanoma, basal cell carcinoma, seborrheic keratosis, dermatofibroma, naevus, dermatitis and psoriasis) were taken with the device (N = 53) and compared with images captured with a reference portable skin ultrasound imager. The investigator and two additional independent experts performed the evaluation. The detectability of skin structures was over 90% for the epidermis, the dermis and the lesions. The morphological and echogenicity information observed for the different skin lesions were found consistent with those of the reference ultrasound device and relevant ultrasound images in the literature. The presented device was able to obtain simultaneous in-vivo optical and ultrasound images of various skin lesions. This has the potential for further investigations, including the preoperative planning of skin cancer treatment.

Quantitative Multispectral Imaging Differentiates Melanoma from Seborrheic Keratosis

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. We found significantly higher intensity values in SKs compared with melanoma, especially with the use of the autofluorescence channel. Moreover, we found a significantly higher number of particles with high fluorescence in SKs. We created a parameter, the SK index, using these values to differentiate melanoma from SK with a sensitivity of 91.9% and specificity of 57.0%. In conclusion, this imaging technique is potentially applicable to distinguish melanoma from SK based on the analysis of various quantitative parameters. For this application, multispectral imaging could be used as a screening tool by general physicians and non-experts in the everyday practice.

Skin Ultrasound as a Diagnostic Approach for Non-melanocytic Benign Skin Tumors

Background. The diagnostic imaging techniques in dermatology, such as skin ultrasound, could improve the diagnosis of non-melanocytic benign tumor lesions, especially those of intradermal and subcutaneous nature. Objective. The general objective of this study was to evaluate the validity and diagnostic safety of high-frequency ultrasound as a diagnostic test for non-melanocytic benign skin tumor detection. The specific objectives were to measure the sensitivity and specificity of ultrasound as a measure of the validity relative to the gold-standard test – diagnostic-therapeutic biopsy. Methods. This study was carried out between January 2017 and June 2019. The patients (n = 641) included in this study comprised of 318 women and 323 men who were between 48 and 74 years. All of them underwent an ultrasound examination of the skin tumor in the dermatology clinic, the removal of the non-melanocytic tumor, and a final histopathological examination. Results. The skin ultrasound has a sensitivity and specificity of 93% and 88%, respectively. Furthermore, the positive and negative predictive values of using skin ultrasound are 84% and 94%, respectively. Conclusion. Skin ultrasound is a diagnostic technique with high sensitivity and specificity in the diagnosis of non-melanocytic skin tumors.