Julia Welzel

Optical coherence tomography in dermatology: a review

Background/aims: Optical coherence tomography (OCT) is a non‐invasive technique for morphological investigation of tissue. Since its development in the late 1980s it is mainly used as a diagnostic tool in ophthalmology. For examination of a highly scattering tissue like the skin, it was necessary to modify the method. Early studies on the value of OCT for skin diagnosis gave promising results.

Optical coherence tomography of the human skin

BACKGROUND Optical coherence tomography (OCT) is a new diagnostic method for tissue characterization. OBJECTIVE We investigated normal and pathologic structures in human skin in several locations to evaluate the potential application of this technique to dermatology. METHODS Based on the principle of low-coherence interferometry, cross-sectional images of the human skin can be obtained in vivo with a high spatial resolution of about 15 microns. Within a penetration depth of 0.5 to 1.5 mm, structures of the stratum corneum, the living epidermis, and the papillary dermis can be distinguished. RESULTS Different layers could be detected that were differentiated by induction of experimental blisters and by comparison with corresponding histologic sections. Furthermore, OCT images of several skin diseases and tumors were obtained. CONCLUSION OCT is a promising new imaging method for visualization of morphologic changes of superficial layers of the human skin. It may be useful for noninvasive diagnosis of bullous skin diseases, skin tumors, and in vivo investigation of pharmacologic effects.

Optical coherence tomography in dermatology

Abstract. Optical coherence tomography (OCT) is a noninvasive diagnostic method that offers a view into the superficial layers of the skin in vivo in real-time. An infrared broadband light source allows the investigation of skin architecture and changes up to a depth of 1 to 2 mm with a resolution between 15 and 3 μm, depending on the system used. Thus OCT enables evaluation of skin lesions, especially nonmelanoma skin cancers and inflammatory diseases, quantification of skin changes, visualization of parasitic infestations, and examination of other indications such as the investigation of nails. OCT provides a quick and useful diagnostic imaging technique for a number of clinical questions and is a valuable addition or complement to other noninvasive imaging tools such as dermoscopy, high-frequency ultrasound, and confocal laser scan microscopy.

Optical coherence tomography in contact dermatitis and psoriasis

Optical coherence tomography (OCT) is a new noninvasive imaging technique. In this study, it was used for the investigation of contact dermatitis and psoriasis. In these common inflammatory skin diseases the value of OCT for quantification and monitoring of the changes in comparison with other bioengineering methods was evaluated. Repeated measurements were performed in healthy volunteers after experimental induction of irritant contact dermatitis and in patients with psoriasis. In the OCT images, the thickness of the epidermis and the signal attenuation coefficient in the upper dermis were evaluated. The changes were compared with measurements of transepidermal water loss, hydration, skin colour and surface roughness, and with high-frequency ultrasound measurements. In irritant dermatitis and psoriasis, thickening of the epidermis was detected and could be monitored over time. The light scattering in the upper dermis was lower than in healthy skin. This was interpreted to be due to the inflammation and oedema, leading to a less-dense arrangement of the collagen fibres. The changes in the OCT images did not significantly correlate with the changes shown by the other methods. OCT is an interesting tool for investigation of inflammatory skin diseases. It is a simple method for determination of epidermal thickness and therefore provides, in addition to other methods, information on the severity of the disease and on treatment effects.

Changes in function and morphology of normal human skin: evaluation using optical coherence tomography.

Background  Optical coherence tomography (OCT) is a noninvasive morphological method for investigating human skin. It allows high‐resolution in vivo imaging of inflammatory skin diseases and tumours. Because it is a newly developed method, systematic studies on standardization and on evaluation of factors influencing the representation of the skin have not yet been performed.

Influence of body water distribution on skin thickness: measurements using high‐frequency ultrasound

Background Although it is known that the skin acts as a water reservoir and participates in the fluid content of the whole body, no method has been established to quantify the fluid shifts in superficial tissue.

The sensitivity and specificity of optical coherence tomography for the assisted diagnosis of nonpigmented basal cell carcinoma: an observational study

The diagnostic criteria for basal cell carcinoma (BCC) using optical coherence tomography (OCT) have been described previously, but the clinical value of these findings remains unknown.

The influence of female sex hormones on skin thickness: evaluation using 20 MHz sonography

Changes in skin thickness and echodensity during the spontaneous menstrual cycle, in women taking hormonal contraceptives and pregnant women were investigated by high‐frequency (20 MHz) ultrasound. Women with a spontaneous ovulatory menstrual cycle (group I), women taking one‐phase contraceptives (group II), women taking three‐phase contraceptives (group III) and pregnant women (group IV) were measured at the following locations: proximal and distal forearm and lower leg on both sides. The skin was investigated during three phases of the menstrual cycle: days 2–4 (phase A), days 12–14 (phase B) and days 20–22 (phase C). Oestradiol and progesterone levels were determined at each phase. The pregnant women were investigated 2 weeks prepartal and 6 weeks after delivery. Group I showed a statistically significant increase in the skin thickness from phase A to phase B, but not from phase B to phase C. Group II showed no significant changes in skin thickness, whereas the skin thickness increased from phase A to phase B in group III. In group IV, the skin was significantly thicker prepartal than after delivery. The measured echodensity showed a negative correlation with skin thickness in group III and in pregnant women. We were able to demonstrate that the status of female sex hormones influences the thickness of the skin. These results can be explained by hormone‐induced water retention in the skin. Sonography at 20 MHz is able to quantify these effects, which should be considered when performing ultrasound measurement in women.

Skin permeability barrier and occlusion: no delay of repair in irritated human skin*

It has been reported that occlusive treatment of irritated skin results in a reduction of barrier repair activities in hairless mice. In contrast, the clinically observed benefit of occlusion in the treatment of hand eczema and other chronic skin diseases with a perturbed barrier function is well–known. While the beneficial effect of occlusion has been proven for the treatment on psoriasis there are no controlled clinical studies of the effect of occlusion on irritated human skin. We have therefore evaluated the effect of various occlusive treatments on repair of the human skin permeability barrier under controlled experimental conditions. Barrier perturbation was induced either by application of sodium lauryl sulfate (SLS) or by repeated tape stripping. This was followed by treatment with different occlusive and semipermeable dressings, partly alter pre‐treatment with petrolatum. Repair of water barrier function was evaluated by daily measurements of transepidermal water loss (TEWL) for 1 week. SLS irritation and tape stripping led to a 6‐fold increase in TEWL as a sign of severe water barrier perturbation, followed by a stepwise decrease over the following days. Occlusion did not significantly delay barrier repair as measured by TEWL. Only in tape‐stripped skin did TEWL stay at high levels during treatment with self‐adhesive dressings. This may be explained by damage of newly formed stratum corneum caused by changing of these membranes. Our results indicate that, in contrast to earlier observations in hairless mouse skin, permeability barrier repair activities are not significantly delayed by occlusive treatment in human skin.

Dynamic Optical Coherence Tomography in Dermatology

Optical coherence tomography (OCT) represents a non-invasive imaging technology, which may be applied to the diagnosis of non-melanoma skin cancer and which has recently been shown to improve the diagnostic accuracy of basal cell carcinoma. Technical developments of OCT continue to expand the applicability of OCT for different neoplastic and inflammatory skin diseases. Of these, dynamic OCT (D-OCT) based on speckle variance OCT is of special interest as it allows the in vivo evaluation of blood vessels and their distribution within specific lesions, providing additional functional information and consequently greater density of data. In an effort to assess the potential of D-OCT for future scientific and clinical studies, we have therefore reviewed the literature and preliminary unpublished data on the visualization of the microvasculature using D-OCT. Information on D-OCT in skin cancers including melanoma, as well as in a variety of other skin diseases, is presented in an atlas. Possible diagnostic features are suggested, although these require additional validation.