A current therapeutic challenge of vascular lesions is that they do not always respond effectively to laser treatment. Information on targeted vessels could potentially be used to guide laser treatments. Optical coherence tomography (OCT) is a useful tool for the non-invasive imaging of tissues, including skin hemangiomas and port wine birthmarks. Dynamic OCT is able to rapidly characterize cutaneous blood vessels. The primary goal of this study was to demonstrate the ability of bedside OCT to image (i) overall vessel pattern; (ii) individual vessel morphology, diameter and depth; and (iii) total vessel density as a function of depth in infantile hemangiomas and port wine birthmarks (PWB). This IRB approved, observational clinical trial was performed among healthy volunteers ages 3 months-73 years old. All patients presented for laser treatment of either infantile hemangiomas or PWB with skin types ranging from Fitzpatrick I-V. OCT imaging of 49 hemangioma and PWB scans were performed pre- and post-treatment. The diameter and depth of the blood vessels making up the vascular lesions were measured. In addition, normal skin was scanned for comparison. Five datasets for infantile hemangiomas and five for PWB that were without motion artifacts were analyzed. Scanned lesions exhibited variable and highly heterogeneous blood vessel patterns with vessel diameters ranging from 20 to 160 μm, suggesting that the laser treatment with single pulse durations may not be optimal. The largest blood vessel diameter observed (160 μm) may not be adequately treated by commonly used pulsed dye laser pulse durations. OCT allowed rapid, non-invasive characterization of the diameter and depth of blood vessels in individual vascular lesions. Imaged lesions consisted of a heterogeneous population of vessel sizes, morphologies, and depth. Future studies could utilize this information to assist development of individualized treatment protocols in an effort to improve vascular birthmark removal. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

BACKGROUND AND OBJECTIVE: Long-term benefits can be predicted by the incorporation of more intelligent systems in lasers and other devices. Such systems can produce more reliable zones of thermal injury when used in association with non-invasive monitoring and precise laser energy delivery. The more classical endpoint of tumor destruction with radiofrequency or long-pulsed (LP) 1064 nm laser is the non-specific appearance of tissue graying and tissue contraction. Herein we discuss combining non-invasive LP 1064 nm Nd:YAG treatment with the assistance of optical coherence tomography (OCT) and the forward-looking infrared (FLIR) thermal camera while testing literature-based formulae for thermal destruction.

Study design/materials and methods

The skin on the forearm and back of two consenting volunteers was marked and anesthetized with lidocaine with epinephrine. The parameters of a scanner-equipped LP 1064 nm Nd:YAG laser were adjusted to achieve an epidermal/superficial dermal heating of between 50°C and 60°C over a specified time course. Experimental single treatments examined various adjusted parameters including, fluence, pulse overlap, pulse duration, scan size, and pulse rate. A FLIR camera was used to record skin temperature. Outcome measures included skin temperature, post-treatment appearance, and OCT assessment of skin and vascular damage. The clinical response of each treatment was followed daily for 4 weeks.

Results

Optimal protocols initially raised the skin temperature to between 55°C and 60°C, which was carefully maintained using subsequent laser passes over a 60-second time course. Immediately post laser, clinical responses included erythema, edema, and blistering. Immediate OCT revealed increased vascularity with intact, dilated blood vessels. Prolonged exposure above 60°C resulted in sub-epidermal blistering and an absence of blood flow in the treatment area with prolonged healing.

Conclusion

The LP 1064 nm laser can be used to achieve heat-related tissue injury, though the narrow parameters necessary for the desired endpoint require the assistance of IR thermal regulation to avoid unacceptable outcomes. The use of the laser scanner ensures precise energy delivery over a defined treatment area. Future studies might explore this as a selective hyperthermic method for the treatment of non-melanoma skin cancer. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Background

Port wine birthmarks (PWBs) are congenital capillary malformations. Vessel characteristics, such as diameter and depth, may impact presentation and outcomes. They can be imaged using dynamic optical coherence tomography, a high-resolution, noninvasive imaging method.

Purpose

We conducted a cross-sectional observational study to measure in vivo vascular characteristics as a function of PWB color.

Methods

Patients undergoing treatment for PWB were recruited from 3 sites. PWBs were classified by color. Dynamic optical coherence tomography images with calculations were obtained.

Results

One hundred eight patients were enrolled. Mean age correlated with PWB color, with birthmarks being lighter in younger patients and darker in older patients (P < .01). Mean superficial plexus depth was significantly shallower in purple PWBs than in pink PWBs. Color was not associated with significant differences in mean superficial vessel density or diameter. Among pink PWBs, each 10-year increase in age was associated with a 10.6-μm increase in superficial plexus depth. Among purple PWBs, each 10-year increase in age was associated with a 16.2-μm reduction in superficial plexus depth. In lesions without prior treatment, vessel density was 12.7% lower in purple PWBs than in pink PWBs.

Conclusion

Superficial vessels of purple PWBs were significantly closer to the epidermis than those of pink PWBs, which might impact optimal laser parameters.

Heating has been known to cure cancer for over 2000 years1, and recent studies have confirmed this in the treatment of basal cell carcinomas (BCC)2. The application of uncontrolled heating often results in unacceptable scarring. Our ability to control the delivery of heat using a forward looking infrared (FLIR) camera and a modulated long pulsed (LP) Nd:YAG 1064nm laser have resulted in better outcomes in comparison to traditional destruction techniques3. Use of optical coherence tomography (OCT) enhances our ability to define the tumor margins prior to treatment. The combination of FLIR and OCT allows very precise treatment of BCCs with at least comparable outcomes to conventional LP Nd:YAG treatments.