Mette Mogensen

Assessment of Optical Coherence Tomography Imaging in the Diagnosis of Non-Melanoma Skin Cancer and Benign Lesions Versus Normal Skin: Observer-Blinded Evaluation by Dermatologists and Pathologists

BACKGROUND Optical coherence tomography (OCT) is an optical imaging technique that may be useful in diagnosis of non‐melanoma skin cancer (NMSC). OBJECTIVES To describe OCT features in NMSC such as actinic keratosis (AK) and basal cell carcinoma (BCC) and in benign lesions and to assess the diagnostic accuracy of OCT in differentiating NMSC from benign lesions and normal skin. METHODS AND MATERIALS OCT and polarization‐sensitive (PS) OCT from 104 patients were studied. Observer‐blinded evaluation of OCT images from 64 BCCs, 1 baso‐squamous carcinoma, 39 AKs, two malignant melanomas, nine benign lesions, and 105 OCT images from perilesional skin was performed; 50 OCT images of NMSC and 50 PS‐OCT images of normal skin were evaluated twice. RESULTS Sensitivity was 79% to 94% and specificity 85% to 96% in differentiating normal skin from lesions. Important features were absence of well‐defined layering in OCT and PS‐OCT images and dark lobules in BCC. Discrimination of AK from BCC had an error rate of 50% to 52%. CONCLUSION OCT features in NMSC are identified, but AK and BCC cannot be differentiated. OCT diagnosis is less accurate than clinical diagnosis, but high accuracy in distinguishing lesions from normal skin, crucial for delineating tumor borders, was obtained.

Morphology and Epidermal Thickness of Normal Skin Imaged by Optical Coherence Tomography

Background: Optical coherence tomography (OCT) is an optical imaging technology with a potential in the non-invasive diagnosis of skin cancer. To identify skin pathologies using OCT, it is of prime importance to establish baseline morphological features of normal skin. Aims: The aim of this study is to describe normal skin morphology using OCT and polarization-sensitive OCT (PS-OCT), which is a way of representing birefringent tissue such as collagen in OCT images. Anatomical locations in 20 healthy volunteers were imaged, and epidermal thickness (ET) was measured and compared to age, gender and skin colour. Methods: OCT imaging is based on infrared light reflection/backscatter from tissue. PS-OCT detects birefringence of tissue. Imaging was performed in 12 skin regions. ET was calculated from the OCT images. Results: Normal skin has a layered structure. Layering is less pronounced in adults. In glabrous skin the stratum corneum is visible. Children had larger ET (p < 0.0001). Age had a negative correlation with ET (p < 0.05). No gender- or skin-type-related differences in ET were found. Conclusion: This study contributes to understanding OCT and PS-OCT images of normal skin and indicates that OCT can be used for both the qualitative and quantitative assessment of skin.

In vivo thickness measurement of basal cell carcinoma and actinic keratosis with optical coherence tomography and 20-MHz ultrasound

Background  Accurate assessment of tumour size is important when planning treatment of nonmelanoma skin cancer (NMSC). Imaging with optical coherence tomography (OCT) has the potential to diagnose and measure depth of NMSC.

OCT imaging of skin cancer and other dermatological diseases

Optical coherence tomography (OCT) provides clinicians and researchers with micrometer-resolution, in vivo, cross-sectional images of human skin up to several millimeter depth. This review of OCT imaging applied within dermatology covers the application of OCT to normal skin, and reports on a large number of applications in the fields of non-melanoma skin cancer, malignant melanomas, psoriasis and dermatitis, infestations, bullous skin diseases, tattoos, nails, haemangiomas, and other skin diseases.

Optical coherence tomography for imaging of skin and skin diseases.

Optical coherence tomography (OCT) is an emerging imaging technology based on light reflection. It provides real-time images with up to 2-mm penetration into the skin and a resolution of approximately 10 microm. It is routinely used in ophthalmology. The normal skin and its appendages have been studied, as have many diseases. The method can provide accurate measures of epidermal and nail changes in normal tissue. Skin cancer and other tumors, as well as inflammatory diseases, have been studied and good agreement found between OCT images and histopathological architecture. OCT also allows noninvasive monitoring of morphologic changes in skin diseases and may have a particular role in the monitoring of medical treatment of nonmelanoma skin cancer. The technology is however still evolving and continued technological development will necessitate an ongoing evaluation of its diagnostic accuracy. Several technical solutions are being pursued to further improve the quality of the images and the data provided, and OCT is being integrated in multimodal imaging devices that would potentially be able to provide a quantum leap to the imaging of skin in vivo.

Machine-learning classification of non-melanoma skin cancers from image features obtained by optical coherence tomography

Background/purpose: A number of publications have suggested that optical coherence tomography (OCT) has the potential for non‐invasive diagnosis of skin cancer. Currently, individual diagnostic features do not appear sufficiently discriminatory. The combined use of several features may however be useful.

Nail thickness measurements using optical coherence tomography and 20-MHz ultrasonography.

Background  Nail diseases are often troubling to the patient and may present a diagnostic challenge to the dermatologist. Biopsies from the nail may be required although often perceived uncomfortable by the patient and potentially scarring. Noninvasive technologies are therefore of particular interest in the study of nails. Optical coherence tomography (OCT) is an optical imaging modality which may provide improved data.

Optical coherence tomography imaging of non-melanoma skin cancer undergoing photodynamic therapy reveals subclinical residual lesions

BACKGROUND Photodynamic therapy with methyl aminolaevulinate (MAL-PDT) is a widely used non-invasive treatment modality for non-melanoma skin cancer (NMSC). The outcome of MAL-PDT is usually primarily evaluated clinically. Optical coherence tomography (OCT) is a non-invasive imaging technology based on interferiometry. OCT has been proven to provide high accuracy in identifying NMSC lesions and performing thickness measurements of thin tumours. OBJECTIVES To describe the OCT morphology in in-vivo NMSC lesions during MAL-PDT treatment and to investigate the use of OCT in evaluating the response of MAL-PDT treated NMSC lesions. METHODS A total of 18 biopsy-proven basal cell carcinomas and actinic keratoses were monitored by OCT during 2 sessions of MAL-PDT treatment. At 3-months follow-up the patients were assessed both by OCT and clinically. If the clinical and OCT evaluation came to different conclusions on recurrence of the lesion, patients were followed more closely at clinical appointments for up to one year after the PDT treatment. RESULTS All lesions displayed at least one OCT characteristic before MAL-PDT treatment. At 3 months follow-up, recurrence was suspected clinically in 5/18 cases, with OCT in 7/18 cases. OCT correctly identified all of the partial responses also found by the clinical examinations. In both cases where recurrence was only found in OCT, this was subsequently confirmed by histology. CONCLUSIONS Our study suggests that OCT identified 29% more recurrences than clinical examination alone. OCT can detect subclinical residual NMSC lesions after MAL-PDT treatment and may therefore be an accurate tool for early detection of residual lesional tissue.

Optical coherence tomography imaging of bullous diseases

Background  Optical coherence tomography (OCT) is a non‐invasive optical imaging technique with a micrometer resolution that may potentially offer real‐time bedside imaging of sufficient detail to allow for morphological discrimination between different types of bullae.

Genome-Wide Association Study in Dachshund: Identification of a Major Locus Affecting Intervertebral Disc Calcification

Intervertebral disc calcification and herniation commonly affects Dachshund where the predisposition is caused by an early onset degenerative process resulting in disc calcification. A continuous spectrum of disc degeneration is seen within and among dog breeds, suggesting a multifactorial etiology. The number of calcified discs at 2 years of age determined by a radiographic evaluation is a good indicator of the severity of disc degeneration and thus serves as a measure for the risk of developing intervertebral disc herniation. The aim of the study was to identify genetic variants associated with intervertebral disc calcification in Dachshund through a genome-wide association (GWA) study. Based on thorough radiographic examinations, 48 cases with ≥ 6 disc calcifications or surgically treated for disc herniation and 46 controls with 0-1 disc calcifications were identified. GWA using the Illumina CanineHD BeadChip identified a locus on chromosome 12 from 36.8 to 38.6 Mb with 36 markers reaching genome-wide significance (P(genome) = 0.00001-0.026). This study suggests that a major locus on chromosome 12 harbors genetic variations affecting the development of intervertebral disc calcification in Dachshund.