Noninvasive Blood Flow Imaging for Real-Time Feedback During Laser Therapy of Port Wine Stain Birthmarks

Huang, Yu-Chih; Tran, Nadia; Nelson, J. Stuart; Choi, Bernard

doi:10.1115/biomed2008-38084

Cited by 15 publications

(27 citation statements)

References 9 publications

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“…Currently, while improving the experimental conditions, we are in the process of designing such a study. Potentially this will reveal useful information, complementary to existing, but relatively complex methods to characterize hemodynamics of PWS such as laser speckle imaging [25], laser Doppler imaging [26] and Doppler optical coherence tomography [27]. In particular the relative phase differences (Fig.…”

Section: Discussionmentioning

confidence: 99%

Remote plethysmographic imaging using ambient light

Verkruysse¹,

Svaasand²,

Nelson³

2008

Opt. Express

1,274

836

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Plethysmographic signals were measured remotely (> 1m) using ambient light and a simple consumer level digital camera in movie mode. Heart and respiration rates could be quantified up to several harmonics. Although the green channel featuring the strongest plethysmographic signal, corresponding to an absorption peak by (oxy-) hemoglobin, the red and blue channels also contained plethysmographic information. The results show that ambient light photo-plethysmography may be useful for medical purposes such as characterization of vascular skin lesions (e.g., port wine stains) and remote sensing of vital signs (e.g., heart and respiration rates) for triage or sports purposes.

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Section: Discussionmentioning

confidence: 99%

Remote plethysmographic imaging using ambient light

Verkruysse¹,

Svaasand²,

Nelson³

2008

Opt. Express

1,274

836

View full text Add to dashboard Cite

show abstract

“…Future work should focus on assessing the flow dynamics of the PWS vasculature following laser irradiation as well as after the combination therapy. Shortly after laser irradiation, perfusion in PWS skin is reduced significantly [42], which may cause local hypoxia and stimulate secretion of angiogenesis-stimulating factors. Perfusion in PWS skin could be monitored with LSI for an extended period of time.…”

Section: Discussionmentioning

confidence: 99%

Long‐term blood vessel removal with combined laser and topical rapamycin antiangiogenic therapy: Implications for effective port wine stain treatment

et al. 2010

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Background and Objectives: Complete blanching of port wine stain (PWS) birthmarks after laser therapy is rarely achieved for most patients. We postulate that the low therapeutic efficacy or treatment failure is caused by regeneration and revascularization of photocoagulated blood vessels due to angiogenesis associated with the skin's normal wound healing response. Rapamycin (RPM), an antiangiogenic agent, has been demonstrated to inhibit growth of pathological blood vessels. Our objectives were to (1) investigate whether topical RPM can inhibit reperfusion of photocoagulated blood vessels in an animal model and (2) determine the effective RPM concentration required to achieve this objective. Study Design/Materials and Methods: For both laseronly and combined laser and RPM treated animals, blood vessels in the dorsal window chambers implanted on golden Syrian hamsters were photocoagulated with laser pulses. Structural and flow dynamics of blood vessels were documented with color digital photography and laser speckle imaging to evaluate photocoagulation and reperfusion. For the combined treatment group, topical RPM was applied to the epidermal side of the window daily for 14 days after laser exposure. Results: In the laser-only group, 23 out of 24 photocoagulated blood vessels reperfused within 5-14 days. In the combined treatment group with different RPM formulae and concentrations, the overall reperfusion rate of 36% was much lower as compared to the laser-only group. We also found that the reperfusion rate was not linearly proportional to the RPM concentration. Conclusions: With topical RPM application, the frequency of vessel reperfusion was considerably reduced, which implies that combined light and topical antiangiogenic therapy might be a promising approach to improve the treatment efficacy of PWS birthmarks. Lasers Surg.

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“…We have used LSI to measure the blood perfusion of PWS skin [12]. A primary design consideration was to collect raw speckle images with subjects positioned as comfortably as possible.…”

Section: Methodsmentioning

confidence: 99%

“…To elucidate the blood flow dynamics during laser surgery, a clinical laser speckle imaging (LSI) instrument has been developed [12], which can provide wide field images to objectively characterize PWS skin perfusion dynamics in real time at specific sites on the lesion. LSI relies on acquisition and analysis of a single image captured at an exposure time that is considerably longer than a characteristic correlation time associated with the fluctuation frequency [13].…”

Section: Introductionmentioning

confidence: 99%

“…Under such conditions, motion of particles, such as red blood cells, induces a blurring of the speckle pattern and hence a loss in speckle contrast [14–16]. A simplified speckle imaging equation has been derived which relates speckle contrast with local blood flow information [12,13]. The advantages of LSI over laser Doppler imaging and Doppler optical coherence tomography include speed, cost, simplicity, and potential ease of integration into current laser systems.…”

Section: Introductionmentioning

confidence: 99%

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Blood flow dynamics after laser therapy of port wine stain birthmarks

et al. 2009

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Background and Objective During laser therapy of port wine stain (PWS) birthmarks, regions of perfusion may persist. We hypothesize that such regions are not readily observable even when laser surgery is performed by highly experienced clinicians. The objective of this study was to use objective feedback to assess the acute vascular response to laser therapy. Study Design/Materials and Methods A clinic-friendly laser speckle imaging (LSI) instrument was developed to provide the clinician with real-time images of blood flow during laser therapy. Images were acquired from patients undergoing laser therapy of PWS birthmarks at Scripps Clinic and the Beckman Laser Institute and Medical Clinic. Blood flow maps were extracted from the acquired imaging data. Histogram-based analysis was applied in grading the degree of heterogeneity present in the blood flow maps after laser therapy. Results Collectively, two types of patient responses were observed in response to laser exposure: (1) an immediate increase in perfusion within minutes after laser therapy; and (2) an overall decrease in blood perfusion ~1 hour after laser therapy, with distinct regions of persistent perfusion apparent in the majority of post-treatment blood-flow images. A comparison of blood flow in PWS and adjacent normal skin demonstrated that PWS blood flow can be greater than, or sometimes equivalent to, that of normal skin. Conclusion In general, a decrease in skin perfusion is observed during pulsed laser therapy of PWS birthmarks. However, a heterogeneous perfusion map was frequently observed. These regions of persistent perfusion may be due to incomplete photocoagulation of the targeted vessels. We hypothesize that immediate retreatment of these regions identified with LSI, will result in enhanced removal of the PWS vasculature.

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Noninvasive Blood Flow Imaging for Real-Time Feedback During Laser Therapy of Port Wine Stain Birthmarks

Cited by 15 publications

References 9 publications

Remote plethysmographic imaging using ambient light

Remote plethysmographic imaging using ambient light

Long‐term blood vessel removal with combined laser and topical rapamycin antiangiogenic therapy: Implications for effective port wine stain treatment

Blood flow dynamics after laser therapy of port wine stain birthmarks

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