OCT in the diagnosis of head and neck pre-cancerous and cancerous cutaneous lesions: An immediate ex vivo study

High speed photo-mediated ultrasound therapy integrated with OCTA

Photo-mediated Ultrasound Therapy (PUT), as a new anti-vascular technique, can promote cavitation activity to selectively destruct blood vessels with a significantly lower amount of energy when compared to energy level required by other laser and ultrasound treatment therapies individually. Here, we report the development of a high speed PUT system based on a 50-kHz pulsed laser to achieve faster treatment, decreasing the treatment time by a factor of 20. Furthermore, we integrated it with optical coherence tomography angiography (OCTA) for real time monitoring. The feasibility of the proposed OCTA-guided PUT was validated through in vivo rabbit experiments. The addition of OCTA to PUT allows for quantitative prescreening and real time monitoring of treatment response, thereby enabling implementation of individualized treatment strategies.

In vivo optical coherence tomography-guided photodynamic therapy for skin pre-cancer and cancer

BACKGROUND

The primary aim of this prospective study is to demonstrate the technical feasibility of OCT to map real tumor margins and to monitor skin changes that occurred post- PDT. Moreover, to optimize PDT efficacy based on the relationship between measured OCT features and treatment outcome.

MATERIAL AND METHODS

A series of 12 patients with overall 18 facial skin lesions were investigated by OCT before surface illumination by PDT to determine tumor free margins. Monitoring of the healing process was undertaken at 3, 6 and 12 months post-PDT. Parameters measured by the in vivo OCT during healing phase were the organization of skin layer and the degree skin fibroses for the active center and peripheral transit zone of the treated lesion. Clinical and aesthetics assessment was carried out at 12-month post-PDT.

RESULTS

Distinct microstructural differences between normal skin, pre-cancer, cancer, and the transition zone between the two tissues were observed on OCT images. In the subsequent healing phase, OCT demonstrate marked delineation and organization of skin layer at late stage of healing. Early features showing bizarre non-homogenous disorganized layering (scab) but afterwards, OCT was able to differentiate between different histological layers. One lesion demonstrated clinical healing by fibrosis (scar) without sign of recurrence. Another lesion demonstrated skin erythema. Only one lesion did not response to treatment despite margins clearance. The CR rate was 95% at the end of the study. The cosmetic effect was "excellent" in 89% of the patients.

CONCLUSIONS

This feasibility study lays the groundwork for using OCT as a real-time, noninvasive monitoring device for PDT in patients with skin cancer.

1.7-Micron Optical Coherence Tomography Angiography for Characterization of Skin Lesions-A Feasibility Study

Optical coherence tomography (OCT) is a non-invasive diagnostic method that offers real-time visualization of the layered architecture of the skin in vivo. The 1.7-micron OCT system has been applied in cardiology, gynecology and dermatology, demonstrating an improved penetration depth in contrast to conventional 1.3-micron OCT. To further extend the capability, we developed a 1.7-micron OCT/OCT angiography (OCTA) system that allows for visualization of both morphology and microvasculature in the deeper layers of the skin. Using this imaging system, we imaged human skin with different benign lesions and described the corresponding features of both structure and vasculature. The significantly improved imaging depth and additional functional information suggest that the 1.7-micron OCTA system has great potential to advance both dermatological clinical and research settings for characterization of benign and cancerous skin lesions.

In vivo optical coherence tomography in assessment of suspicious facial lesions: A prospective study

BACKGROUND

Skin cancer continues to be the most common cancer in the Caucasian population. Over the past two decades, researchers around the world started assessing the possibility of diagnosing tissue pathologies by using optical systems. In this study, we aimed to use in vivo optical coherence tomography (OCT) technology to describe the morphologic features of normal and pathologic skin conditions.

MATERIALS AND METHODS

In this study, 72 patients with suspected skin pre-cancer/cancer were recruited. The lesions were subjected to in vivo OCT scanning using compact size probe. The main scanned areas were the centre of the lesion, periphery of the lesion and control reading at least 2cm from the lesion periphery but within the same dermatomal distribution. Following assessment, each lesion was surgically excised. All acquired OCT images were correlated with the corresponding histopathology images to ensure an accurate diagnosis and appropriate co-localisation of abnormal lesion on both OCT image and pathology slide. This was achieved in every resected lesion.

RESULTS

Histopathological analysis revealed that of the 96 macroscopically suspicious scanned lesions 26 were actinic keratosis (AK), 51 were basal cell carcinoma (BCC) and 19 were cutaneous squamous cell carcinoma (SCC). Different layers of healthy skin can be distinguished with clear demarcation between the epidermis and papillary dermis. An increase in epidermal thickness was observed in OCT images in AK that appeared relatively hyperintense. Cutaneous SCC was characterized by hypoechoic signal free spaces within the dermis and damaged of dermal-epidermal junction. BCCs were visualized as hypoechoic structures but showed a mixed echogenicity. Solid nodular BCC appeared as single or multiple areas with no clear arrangement surrounding low-reflectivity lobular structures surrounded. Cystic structures were identifiable by signal-free areas adjacent to healthy skin. Sensitivity and specificity for in vivo OCT in diagnosing these lesions were impressive, based on this small sample size.

CONCLUSIONS

OCT have shown that there are qualitative differences in OCT image features of skin with varying degrees of pathology, and between normal and pathological skin. This study indicates that in vivo OCT shows a good promise as a useful optical diagnostic technique in diagnosing skin pathologies.

Optical coherence tomography-based non-invasive evaluation of premalignant lesions in SKH-1 mice

Non-invasively diagnosis of actinic keratoses (AK) is important for preventing cutaneous squamous cell carcinoma (cSCC). Optical coherence tomography (OCT) can be used to detect the cross-sectional skin micromorphology with sufficient resolution and imaging depth. It has the capability to reveal the changes in skin microstructure during the development of AK. Therefore, OCT can serve as a tool for diagnosing AK. This study explores the feasibility of OCT in evaluating the structural changes in mouse skin at the different stages following exposure to ultraviolet radiation. The performance of OCT is compared with histology, the gold standard in this context. The imaging results demonstrate that a wave-shaped irregular dermo-epidermal junction (DEJ), as well as the continuous thickening of the epidermis, are useful diagnostic parameters for diagnosing AK. Histological examinations confirm these observations. These findings emphasize the need for effective skin protection or medical treatment once changes in the DEJ and epidermis are detected. OCT shows strong potential for non-invasive evaluation of such changes and AK development, and can be used for the prevention of cSCC without the necessity of taking biopsies.

Application of optical coherence tomography to study the structural features of oral mucosa in biopsy tissues of oral dysplasia and carcinomas

OBJECTIVE

This study aims to examine the ability of optical coherence tomography (OCT) to differentiate ex vivo epithelial structure of benign disorders, dysplastic, and oral squamous cell carcinoma (OSCC) in comparison with the structure of normal marginal mucosa of oral biopsies. As a secondary objective, we examined the inter- and intra-observer variations of OCT measurements of two calibrated assessors.

MATERIALS AND METHODS

Oral biopsies (n = 44) were scanned using the swept source OCT (SSOCT) and grouped by pathology diagnosis to benign, dysplasia or carcinoma. Two trained and calibrated assessors scored on the five OCT variables: thickness of keratin layer (KL), epithelial layer (EL), homogeneity of lamina propria (LP), basement membrane integrity (BMI), and the degree of reflection of the epithelial layer (Ep Re). Chi-square tests and Fischer's exact method were used to compare the data.

RESULTS

The OCT images showed breached BM status in all the OSCC samples (100%). Epithelial reflection was noted to be hyper-reflective in all the OSCC and oral dysplasia samples (100%). An increase in KL in 66.67% of the OSCC and 100% of the oral dysplasia samples was found. EL was increased in all the OSCC samples (100%) and 85.72% of the oral dysplasias. Kappa values showed that there was very good agreement (over 0.7) when scoring individual parameters between the two assessors.

CONCLUSION

The study showed that the BM status was a key parameter in the detection of SCC and for differentiating SCC from oral dysplasia or benign disorders.

CLINICAL RELEVANCE

OCT is a non-invasive and non-radioactive adjunct diagnostic tool that can provide immediate results on the structure of oral mucosa. The BM status measured ex vivo was a key parameter in the detection of SCC and for differentiating SCC from oral dysplasia or benign disorders.

Structural validation of facial skin using optical coherence tomography: A descriptive study

BACKGROUND

In this immediate ex vivo study, we aimed to identify the structures of normal and pathological facial skin using optical coherence tomography (OCT) and compared them to the gold standard histopathology.

MATERIAL AND METHODS

A total of 53 patients, with 57 suspicious facial lesions, participated in this study. A set of variables have been highlighted by the pathologist to represent the minimum unique features that could be used to diagnose a skin pathology have been included in a checklist. One pathologist used this checklist while examining the histopathology slides and one clinician while examining the OCT images. The data from both checklists have been reviewed and compared.

RESULTS

Optical coherence tomography's overall accuracy in diagnosing AK was 83%. Best accuracy was achieved in diagnosing BCC and was 97%, while it was 85% for cutaneous SCC. OCT failed to diagnose LM with an accuracy of 33.3% based on the two parameters of the pathology checklist, while it was 81% for malignant melanoma.

CONCLUSION

This study proved the success of OCT in identifying structural changes in normal and pathological facial skin. Further studies to prove its usefulness in vivo are recommended.