In vivo assessment of optical properties of basal cell carcinoma and differentiation of BCC subtypes by high-definition optical coherence tomography

Sclerodermiform Cell Epithelioma of the Palpebromalar Region

This report describes a recurrent sclerodermiform basal cell epithelioma of the malar region next to the inferior eyelid in a 57-year-old woman. Three interventions were necessary to obtain a clear margin of resection. The area of resection was closed with a local cutaneous flap. We report a rare basal cell carcinoma subtype underestimated in its aggressiveness with often inadequate medical and surgical management. This tumor, generally localized in the face, often requires aggressive surgery, and aesthetic results can be poor. The patients require close long-term follow-up even when margins are clear. General practitioners, dermatologists, and surgeons should be aware of sclerodermiform basal cell carcinoma, which is a malignant, aggressive, and recurrent tumor.

Cross-Polarization Optical Coherence Tomography for Clinical Evaluation of Dermal Lesion Degrees in Vulvar Lichen Sclerosus

The aim of the study was to identify different degrees of dermal lesions in vulvar lichen sclerosus (VLS) using cross-polarization optical coherence tomography (CP OCT) based on attenuation coefficient to detect disease early manifestations and to monitor the effectiveness of treatment.

Materials and Methods

The study included 10 patients without pathology and 39 patients with VLS diagnosed histologically. CP OCT was performed in vivo on the inner surface of the labia minora, in the main lesion area. From each scanning point, a 3.4×3.4×1.25-mm3 3D data array was obtained in 26 s. CP OCT examination results were compared with histological examination of specimens stained with Van Gieson's picrofuchsin.Quantitative analysis of OCT images was performed by measuring the attenuation coefficient in co-polarization and cross-polarization. For visual analysis, color-coded charts were developed based on OCT attenuation coefficients.

Results

According to histological examination, all patients with VLS were divided into 4 groups as per dermal lesion degree: initial (8 patients); mild (7 patients); moderate (9 patients); severe (15 patients). Typical features of different degrees were interfibrillary edema up to 250 μm deep for initial degree, thickened collagen bundles without edema up to 350 μm deep for mild degree, dermis homogenization up to 700 μm deep for moderate degree, dermis homogenization and total edema up to 1200 μm deep for severe degree.Pathological processes in dermis during VLS like interfibrillary edema and collagen bundles homogenization were visualized using CP OCT method based on values of attenuation coefficient in co- and cross-polarization channels. However, CP OCT method appeared to be less sensitive to changes of collagen bundles thickness not allowing to distinguish thickened collagen bundles from normal ones with enough statistical significance. The CP OCT method was able to differentiate all degrees of dermal lesions among themselves. OCT attenuation coefficients differed from normal condition with statistical significance for all degrees of lesions, except for mild.

Conclusion

For the first time, quantitative parameters for each degrees of dermis lesion in VLS, including initial degree, were determined by CP OCT method allowing to detect the disease at an early stage and to monitor the applied clinical treatment effectiveness.

Fiber‐based hand‐held RCM‐OCT probe for noninvasive assessment of skin lesions and therapy guidance

Noninvasive assessment of skin lesions, especially of basal cell carcinoma (BCC), has benefited more recently from the use of optical imaging techniques such as optical coherence tomography (OCT) and reflectance confocal microscopy (RCM). While RCM provides submicron scale resolution and thus enables identification of skin morphological changes of the skin, with the downside of limited penetration depth, OCT imaging of the same lesion brings the benefit of better resolving its depth of invasion. OCT and RCM can be used either individually or combined within the same instrument for the noninvasive diagnosis of nonmelanoma skin cancers (NMSCs). Their combined use has shown to provide certain benefits such as better characterization of the lesion's margins, both in depth and laterally, as well as improved sensitivity and specificity, as previously demonstrated by our team. In this paper we report a new "fiber-based" implementation of the second-generation RCM-OCT hand-held probe. The fiber-based implementation of both imaging modalities enabled the construction of a smaller footprint/lower weight hand-held probe. Its preliminary evaluation on the skin of healthy volunteers is reported here, demonstrating improved capabilities for resolving sub-cellular structures and image skin morphology with micron-scale resolution to a higher depth than in the previous implementation, while also enabling the construction of angiography maps showing vascular remodeling.

Manually scanned single fiber optical coherence tomography for skin cancer characterization

Optical coherence tomography (OCT) is a cross-sectional imaging modality based on low coherence light interferometry. Within dermatology, it has found applications for in vivo diagnostic imaging purposes, as well as to guide Mohs micrographic surgery (MMS), due to its ability to visualize skin morphology up to several millimeters in depth. However, standard OCT probes have a large footprint and capture an extended area of the skin, making it difficult to precisely pinpoint clinically relevant location being imaged. Mohs surgeons stand to benefit from a handheld in vivo imaging device that can accurately trace surgical margins. In this study, we demonstrate the use of a single fiber OCT (sfOCT) instrument. Our imaging system features a miniature common path single fiber probe, and a novel speckle decorrelation technique that generates distortion free 2D images from manual scanning.By manually moving the single-fiber probe across the region of interest, the user can perform a lateral OCT scan while visualizing the location of the probe during data acquisition. Using the sfOCT, we have identified normal skin morphology, qualitatively correlated features of basal cell carcinoma and squamous cell carcinoma with histopathology, and quantified the disruption of the dermo-epidermal junction OCT pattern in skin tumors-each demonstrating the potential of utilizing sfOCT to differentiate tumor from normal skin. Using this imaging tool, a Mohs surgeon can enhance determination of surgical margins for the first stage of MMS, potentially decreasing the time and number of stages required for complete tumor removal.

Application of Cellular Resolution Full-Field Optical Coherence Tomography in vivo for the Diagnosis of Skin Tumours and Inflammatory Skin Diseases: A Pilot Study

BACKGROUND

Optical coherence tomography (OCT) has been shown to provide non-invasive diagnosis of common skin neoplasms, especially basal cell carcinoma. OCT produces a cross-sectional view of the tissue, similar to a traditionally sectioned histopathological view, but the resolution of conventional OCT is low and thus limits clinical application.

OBJECTIVES

This study aimed to investigate the application ability of a full-field (FF)OCT system which was newly developed to scan the skin at the cellular level.

METHODS

Patients with skin tumours or inflammatory lesions warranting biopsy were consecutively enrolled. All lesions underwent clinical, dermoscopic, and OCT assessment, followed by routine biopsy. The adjacent normal skin was scanned for comparison. OCT images were interpreted (blinded to the biopsy results) and then compared with the histopathological diagnosis.

RESULTS

A total of 111 patients with 115 lesions completed the protocol, including 80 skin tumours, 28 inflammatory diseases, and 7 other diseases. Of the OCT images, 43.5% were of good quality and show expected features. Identifiable features of actinic keratosis, Bowen's disease, basal cell carcinoma, extramammary Paget's disease, seborrheic keratosis, large cell acanthoma, bullous pemphigoid, interface dermatitis, lichenoid tissue reaction, and psoriasis were demonstrated. Lesions are located deeply, and so some features were out of the field of view, accounting for 40.0% (46/115).

CONCLUSIONS

This study expanded the ability of FFOCT for the clinical diagnosis of various skin conditions. This new optical technique can clearly visualise skin lesions located in the epidermis and upper dermis. It provided an effective way to perform digital skin biopsy in superficial skin diseases.

The potential utility of integrated reflectance confocal microscopy-optical coherence tomography for guiding triage and therapy of basal cell carcinomas

The increasing rate of incidence and prevalence of basal cell carcinomas (BCCs) worldwide, combined with the morbidity associated with conventional surgical treatment has led to the development and use of alternative minimally invasive non-surgical treatments. Biopsy and pathology are used to guide BCC diagnosis and assess margins and subtypes, which then guide the decision and choice of surgical or non-surgical treatment. However, alternatively, a noninvasive optical approach based on combined reflectance confocal microscopy (RCM) and optical coherence tomography (OCT) imaging may be used. Optical imaging may be used to guide diagnosis and margin assessment at the bedside, and potentially facilitate non-surgical management, along with long-term monitoring of treatment response. Noninvasive imaging may also complement minimally invasive treatments and help further reduce morbidity. In this paper, we highlight the current state of an integrated RCM/OCT imaging approach for diagnosis and triage of BCCs, as well as for assessing margins, which therefore may be ultimately used for guiding therapy.

Techniques and Applications in Skin OCT Analysis

The skin is the largest organ of our body. Skin disease abnormalities which occur within the skin layers are difficult to examine visually and often require biopsies to make a confirmation on a suspected condition. Such invasive methods are not well-accepted by children and women due to the possibility of scarring. Optical coherence tomography (OCT) is a non-invasive technique enabling in vivo examination of sub-surface skin tissue without the need for excision of tissue. However, one of the challenges in OCT imaging is the interpretation and analysis of OCT images. In this review, we discuss the various methodologies in skin layer segmentation and how it could potentially improve the management of skin diseases. We also present a review of works which use advanced machine learning techniques to achieve layers segmentation and detection of skin diseases. Lastly, current challenges in analysis and applications are also discussed.

S2k Guidelines for Cutaneous Basal Cell Carcinoma - Part 1: Epidemiology, Genetics and Diagnosis

Basal cell carcinoma is the most common malignant tumor among fair-skinned individuals, and its incidence has been rising steadily in the past decades. In order to maintain the highest quality of patient care possible, the German S2k guidelines were updated following a systematic literature search and with the participation of all professional societies and associations involved in the management of the disease. Part 1 highlights new developments in genetics in particular as well as aspects regarding epidemiology, diagnosis, and histology.

Differentiation of Different Nonmelanoma Skin Cancer Types Using OCT

BACKGROUND

Early detection of various types of nonmelanoma skin cancer has been a challenge in dermatology. Noninvasive examination procedures such as optical coherence tomography (OCT) play an increasingly important role, besides the established gold standard of histological tissue sample analysis. OCT is a noninvasive, cross-sectional, real-time technique that allows conclusions to be drawn with regard to the presence of pathologies.

OBJECTIVE

The objective of this study was to investigate whether it is possible to distinguish between different types of nonmelanoma skin cancer using OCT or not.

METHODS

A study population of a total of 25 cases, comprising 5 cases, each, of 5 tumor entities (i.e., basal cell carcinoma, superficial basal cell carcinoma, actinic keratosis, squamous cell carcinoma, and Bowen disease) was examined. Relevant lesions were scanned both centrally and peripherally in the multislice mode. All OCT images were blinded, randomized, analyzed, and evaluated by 2 clinicians experienced in OCT.

RESULTS

This study demonstrated that it is possible to determine correlations between various types of tumors and recurring tumor characteristics.

CONCLUSION

This study showed that it is possible to distinguish between the different nonmelanoma skin cancers by using OCT, but further prospective studies have to be conducted to validate the sensitivity and specificity of the criteria.

The value of ultrahigh resolution OCT in dermatology - delineating the dermo-epidermal junction, capillaries in the dermal papillae and vellus hairs

Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised of the lower surface of a single cell layer in epidermis (the stratum basale) connected to an even thinner membrane (the basement membrane). The basement membrane is attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system (Vivosight from Michaelson Diagnostics) and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. To our knowledge no detailed delineating of the DEJ in the UHR-OCT image has previously been reported, despite many publications within this field. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20 μm, and in imaging the dermal papillae where, when utilising the UHR-OCT, capillary structures are identified in the hand palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.

Advances in optical coherence tomography in dermatology-a review

Optical coherence tomography (OCT) was introduced as an imaging system, but like ultrasonography, other measures, such as blood perfusion and polarization of light, have enabled the technology to approach clinical utility. This review aims at providing an overview of the advances in clinical research based on the improving technical aspects. OCT provides cross-sectional and en face images down to skin depths of 0.4 to 2.00 mm with optical resolution of 3 to 15  μm. Dynamic optical coherence tomography (D-OCT) enables the visualization of cutaneous microvasculature via detection of rapid changes in the interferometric signal of blood flow. Nonmelanoma skin cancer (NMSC) is the most comprehensively investigated topic, resulting in improved descriptions of morphological features and diagnostic criteria. A refined scoring system for diagnosing NMSC, taking findings from conventional and D-OCT into account, is warranted. OCT diagnosis of melanoma is hampered by the resolution and the optical properties of melanin. D-OCT may be of value in diseases characterized with dynamic changes in the vasculature of the skin and the addition of functional measures is strongly encouraged. In conclusion, OCT in dermatology is still an emerging technology that has great potential for improving further in the future.

Optical mapping of nonmelanoma skin Cancers-A pilot clinical study

BACKGROUND AND OBJECTIVE

Nonmelanoma skin cancer (NMSC) is the most common human cancer. Because these tumors often affect the face, there is a strong need for both accurate removal of these neoplasms to prevent recurrence and maximal tissue preservation to prevent cosmetic or functional deformity. Polarization-enhanced reflectance and fluorescence imaging (PERFI) is a new bedside method that uses fluorescent chromophores to image NMSC. While the feasibility of the technique has been successfully demonstrated in ex vivo studies, this is the first pilot study to extend the use of PERFI to in vivo intraoperative imaging of NMSC.

MATERIALS AND METHODS

Subjects were recruited from a population of patients with biopsy-confirmed NMSC, scheduled for Mohs micrographic surgery. Eight cases were studied. Sterile methylene blue (MB) was diluted in anaesthetic solution and infused into the peritumoral space. Digital photographs of the lesion were taken and Mohs surgery was performed. Then, the surgical bed was re-imaged. Each excision was also imaged ex vivo and processed for routine histopathology. Optical images were processed and compared with histopathology.

RESULTS AND CONCLUSIONS

The injection of MB was well tolerated. We observed a transient blue staining of the treated area, which disappeared completely within 1 week in all of the patients. In all subjects, the contrast agent, MB, was preferentially retained in the tumor. The ex vivo images correlated well with histopathology. In vivo images qualitatively delineated the tumor margins. The results of our pilot trial indicate that PERFI may be useful for accurate and rapid delineation of NMSC during surgery. Lasers Surg. Med. 49:803-809, 2017. © 2017 Wiley Periodicals, Inc.

Master/slave optical coherence tomography imaging of eyelid basal cell carcinoma

Optical coherence tomography (OCT) is fast emerging as an additional non-interventional modality for skin tumor detection and diagnosis. A master/slave flying spot OCT configuration was assembled to detect periocular basal cell carcinomas (BCC). A swept source at 1300 nm and sweeping speed of 50 kHz were used. A three-step process was involved. First, 384 channeled spectra using a mirror were stored for 384 optical path differences at the master stage. Then, the stored channeled spectra (masks) were correlated with the channeled spectrum from the BCC tissue to produce 384 en face OCT images (200×200 pixels) for the optical path difference values used to acquire the masks. Finally, these en face slices were stacked to form a volume to cross-reference BCC tumor margins in the orthogonal plane. Per each eyelid sample, several en face images of 200×200 lateral pixels are produced in the time to scan laterally a complete raster of 1.6 s. Combination of the en face views with the cross-sectioning views allow for better discrimination of BCCs comparable to using cross-sectional imaging alone, as previously reported using the conventional fast-Fourier-transform-based OCT techniques.