Burn Depth Assessment Research Articles

A comparison of non-invasive imaging modalities: Infrared thermography, spectrophotometric intracutaneous analysis and laser Doppler imaging for the assessment of adult burns

BackgroundCurrently, the only evidence-based adjunct to clinical evaluation of burn depth is laser Doppler imaging (LDI), although preliminary studies of alternative imaging modalities with instant image acquisition are promising. This is a study to investigate the accuracy of infrared thermography (IRT) and spectrophotometric intracutaneous analysis (SIA) for burn depth assessment, and compare this to the current gold standard: LDI. We include a comparison of the three modalities in terms of cost, reliability and usability. MethodsWe recruited 20 patients with burns presenting to the Chelsea and Westminster Adult Burns Service. Between 48h and 5 days afterburn we recorded imaging using moorLDI2-BI-VR (LDI), FLIR E60 (IRT) and Scanoskin™ (SIA). Subsequent clinical management and outcome was as normal, and not affected by the extra images taken. Results24 burn regions were grouped according to burn wound healing: group A healed within 14 days, group B within 14–21 days, and group C took more than 21 days or underwent grafting. Both LDI and IRT accurately determined healing potential in groups A and C, but failed to distinguish between groups B and C (p>0.05). Scanoskin™ interpretation of SIA was 100% consistent with clinical outcome. ConclusionFLIR E60 and Scanoskin™ both present advantages to moorLDI2-BI-VR in terms of cost, ease-of-use and acceptability to patients. IRT is unlikely to challenge LDI as the gold standard as it is subject to the systematic bias of evaporative cooling. At present, the LDI colour-coded palette is the easiest method for image interpretation, whereas Scanoskin™ monochrome colour-palettes are more difficult to interpret. However the additional analyses of pigment available using SIA may help more accurately indicate the depth of burn compared with perfusion alone. We suggest development of Scanoskin™ software to include a simplified colour-palette similar to LDI and additional work to further investigate the potential of SIA as an alternative to the current gold standard.

Utility of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) to non-invasively diagnose burn depth in a porcine model

Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter (μ′s) and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time.

Region-based approach for the spectral clustering Nyström approximation with an application to burn depth assessment

Image segmentation methods based on spectral graph theory, although capable of overcoming some of the drawbacks of the so-called "central"-grouping methods, are computationally expensive and quickly become infeasible to solve as the size of the image grows. As a counter measure, the Nystrom approximation allows to extrapolate the complete grouping solution for these methods using only a proportionally smaller set of samples instead of the whole pixels that compose the image. In this correspondence, we further explore the Nystrom approximation by taking the concept of "regions", pixels of the image previously grouped by a central method, to both reduce the computational resources required and provide a finer segmentation of the image by combining the strengths of both methods. We apply the proposed approach to the segmentation of images of burns where we attempt to extract regions that would roughly correspond to the different degrees of the lesion.

Termal Deri Yanıklarında Yanık Derinliğinin Değerlendirilmesi

Yanık derinliği, yanık yarasındaki sağlıklı ve nekrotik doku arasında gözlenen anatomik sınırın genişliği olarak tanımlanır. Yanık derinliğinin erken ve doğru bir şekilde belirlenmesi yanıklı hastaların tedavisi ve prognozu için çok önemlidir. Termal yanıklarda asıl önemli problem, yüzeysel ve derin dermal yanıklar arasındaki farklılığı ortaya koymaktır. Yanığın derinliği, etiyolojik ajanın ısı derecesi ve temas süresiyle ilişkili olarak dokulara transfer olan enerjiyle alakalıdır. Yüzeysel dermal yanıklar genellikle minimal skarlı reepitelizasyonla iyileşirken, daha derin yanıklar hipertrofik veya kontraktil skar dokusu ile iyileşebilmektedir. Derin dermal ve tam katman yanıkların tedavisi için genellikle greft uygulaması ve cerrahi eksizyon gereklidir. Buna ek olarak zamanında müdahale edilmezse, birçok yüzeysel yanık yarası daha derin yaralara dönüşebilir. Bu nedenle yanık derinliğinin çabuk ve doğru değerlendirilmesi yanıkların tedavisi için öncelikli bir durumdur. Yanık derinliğinin değerlendirilmesinde klinik veriler en yaygın kullanılan metot olmasına rağmen son teknolojik ilerlemelerle birlikte farklı değerlendirme metotları hem araştırılmaya hem de kullanılmaya başlanmıştır. Klinik değerlendirmeler dışında kullanılan diğer yöntemler; biyopsi ve histolojik değerlendirme, termografi, vital boyamalar, indosiyanin yeşil video anjiyografi ve lazer-Doppler gibi perfüzyon ölçme teknikleri ile geçerliliği henüz tam olarak kanıtlanmayan optik değerlendirme, nükleer görüntüleme ve tomografik yöntemlerden oluşmaktadır. Bu çalışmanın amacı, yanık derinliğinin değerlendirilmesinde geçmişten günümüze kullanılan yöntemler hakkında bilgiler vererek en uygun yöntem(in)lerin belirlenmesine ışık tutmaktır.

Examination of the Early Diagnostic Applicability of Active Dynamic Thermography for Burn Wound Depth Assessment and Concept Analysis.

Despite advances in perfusion imaging, burn wound imaging technology continues to lag behind that of other fields. Quantification of blood flow is able to predict time for healing, but clear assessment of burn depth is still questionable. Active dynamic thermography (ADT) is a noncontact imaging modality capable of distinguishing tissue of different thermal conductivities. Utilizing the abnormal heat transfer properties of the burn zones, we examined whether ADT was useful in the determination of burn depth in a model of early burn wound evaluation. Duroc pigs (castrated male; n = 3) were anesthetized, and two burns were created with an aluminum billet at 3 and 12 seconds. These contact times resulted in superficial partial and deep partial thickness burn wounds, respectively. ADT and laser Doppler imaging (LDI) imaging were performed every 30 minutes postburn for a total of five imaging sessions ending 150 minutes postburn. For ADT, imaging excitation was performed for 42-120 seconds with dual quartz-infrared lamps, and subsequent infrared image capture was performed for 300 seconds. MATLAB-assisted image analysis was performed to determine burn zone region of interest thermal relaxation and characteristic patterns. LDI was performed with a moorLDI system, and biopsies were captured for histology following the 150-minute imaging session. Both ADT and LDI imaging modalities are able to detect different physical properties at 30, 60, 90 120, and 150 minutes postburn with statistical significance (P < 0.05). Resultant ADT cooling curves characterize greater differences with greater stimulation and a potentially more identifiable differential cooling characteristic. Histological analysis confirmed burn depth. This preliminary work confirms that ADT can measure burn depth and is deserving of further research either as a stand-alone imaging technology or in combination with a device to assess perfusion.

Utilization of laser Doppler flowmetry and tissue spectrophotometry for burn depth assessment using a miniature swine model.

Currently, the diagnosis of burn depth is primarily based on a visual assessment and can be dependent on the surgeons' experience. The goal of this study was to determine the ability of laser Doppler flowmeter combined with a tissue spectrophotometer to discriminate burn depth in a miniature swine burn model. Burn injuries of varying depth, including superficial-partial, deep-partial, and full thickness, were created in seven Göttingen minipigs using an aluminium bar (100 °C), which was applied to the abdominal skin for periods of 1, 3, 6, 12, 30, and 60 seconds with gravity alone. The depth of injury was evaluated histologically using hematoxylin and eosin staining. All burns were assessed 3 hours after injury using a device that combines a laser light and a white light to determine blood flow, hemoglobin oxygenation, and relative amount of hemoglobin. The blood flow (41 vs. 124 arbitrary units [AU]) and relative amount of hemoglobin (32 vs. 52 AU) were significantly lower in full thickness compared with superficial-partial thickness burns. However, no significant differences in hemoglobin oxygenation were observed between these depths of burns (61 vs. 60%). These results show the ability of laser Doppler flowmeter and tissue spectrophotometer in combination to discriminate between various depths of injury in the minipig model, suggesting that this device may offer a valuable tool for burn depth assessment influencing burn management.

Objective Burn Assessment Using Laser Doppler Imaging and Indocyanine Green Videoangiography to Evaluate the Effect of Hyperbaric Oxygen Treatment: A Case Report

Introduction: Several relatively new technologies have served as valuable adjuncts to clinical judgment in burn wound depth assessment. Among these technologies, laser Doppler imaging and indocyanine green videoangiography have improved accuracy of burn depth assessment. However, an objective way to monitor improvement and changes in blood flow after hyperbaric oxygen treatment is not well documented. Methods: We present a case of a 43 year-old African American female patient whose burns we evaluated with laser Doppler imaging and indocyanine green videoangiography prior to and after hyperbaric oxygen therapy (HBOT). Results: These imaging modalities documented an improvement in perfusion of the burned tissues in our patient. Conclusions: Though we need more comparative data in the form of prospective studies with large cohorts to make concrete recommendations, we suggest with our case report that laser Doppler imaging and indocyanine green videoangiography can be used to monitor improvement and document blood flow after HBOT.

Noncontact imaging of burn depth and extent in a porcine model using spatial frequency domain imaging.

The standard of care for clinical assessment of burn severity and extent lacks a quantitative measurement. In this work, spatial frequency domain imaging (SFDI) was used to measure 48 thermal burns of graded severity (superficial partial, deep partial, and full thickness) in a porcine model. Functional (total hemoglobin and tissue oxygen saturation) and structural parameters (tissue scattering) derived from the SFDI measurements were monitored over 72 h for each burn type and compared to gold standard histological measurements of burn depth. Tissue oxygen saturation (stO₂) and total hemoglobin (ctHbT) differentiated superficial partial thickness burns from more severe burn types after 2 and 72 h, respectively (p < 0.01), but were unable to differentiate deep partial from full thickness wounds in the first 72 h. Tissue scattering parameters separated superficial burns from all burn types immediately after injury (p < 0.01), and separated all three burn types from each other after 24 h (p < 0.01). Tissue scattering parameters also showed a strong negative correlation to histological burn depth as measured by vimentin immunostain (r² > 0.89). These results show promise for the use of SFDI-derived tissue scattering as a correlation to burn depth and the potential to assess burn depth via a combination of SFDI functional and structural parameters.

Real-time photoacoustic imaging system for burn diagnosis.

We have developed a real-time (8 to 30 fps) photoacoustic (PA) imaging system with a linear-array transducer for burn depth assessment. In this system, PA signals originating from blood in the noninjured tissue layer located under the injured tissue layer are detected and imaged. A compact home-made high-repetition-rate (500 Hz) 532-nm fiber laser was incorporated as a light source. We used an alternating arrangement for the fibers and sensor elements in the probe, which improved the signal-to-noise ratio, reducing the required laser energy power for PA excitation. This arrangement also enabled a hand-held light-weight probe design. A phantom study showed that thin light absorbers embedded in the tissue-mimicking scattering medium at depths >3 mm can be imaged with high contrast. The maximum error for depth measurement was 140 μm. Diagnostic experiments were performed for rat burn models, including superficial dermal burn, deep dermal burn, and deep burn models. Injury depths (zones of stasis) indicated by PA imaging were compared with those estimated by histological analysis, showing discrepancies 200 μm. The system was also used to monitor the healing process of a deep dermal burn. The results demonstrate the potential usefulness of the present system for clinical burn diagnosis.

Deep tissue imaging using spectroscopic analysis of multiply scattered light

Scattering limits the penetration depth of most optical imaging techniques. Efforts to overcome this limitation often require complex optical or computational schemes. We have developed a new method of assessing tissue properties based on spectroscopic analysis of multiply scattered light. The technique, multispectral multiple-scattering low-coherence interferometry (ms2/LCI), uses coherence and spatial gating to produce images of tissue optical properties up to 9 mm deep, with millimeter-scale resolution. The capabilities of ms2/LCI are demonstrated using tissue phantoms composed of chicken breast. Discrimination of diseased and healthy tissues is shown through imaging and analysis of burns in ex vivo human skin samples. Our technique may provide a powerful way to assess burn depth and progression in sensitive, burned tissues where physical contact is undesirable.

A systematic review of the evolution of laser Doppler techniques in burn depth assessment.

Aims. The introduction of laser Doppler (LD) techniques to assess burn depth has revolutionized the treatment of burns of indeterminate depth. This paper will systematically review studies related to these two techniques and trace their evolution. At the same time we hope to highlight current controversies and areas where further research is necessary with regard to LD imaging (LDI) techniques. Methods. A systematic search for relevant literature was carried out on PubMed, Medline, EMBASE, and Google Scholar. Key search terms included the following: “Laser Doppler imaging,” “laser Doppler flow,” and “burn depth.” Results. A total of 53 studies were identified. Twenty-six studies which met the inclusion/exclusion criteria were included in the review. Conclusions. The numerous advantages of LDI over those of LD flowmetry have resulted in the former technique superseding the latter one. Despite the presence of alternative burn depth assessment techniques, LDI remains the most favoured. Various newer LDI machines with increasingly sophisticated methods of assessing burn depth have been introduced throughout the years. However, factors such as cost effectiveness, scanning of topographically inconsistent areas of the body, and skewing of results due to tattoos, peripheral vascular disease, and anaemia continue to be sighted as obstacles to LDI which require further research.

Active dynamic infrared thermal imaging in burn depth evaluation.

The aim of this study was to find the relationship between active dynamic thermography (ADT) with cold excitation and burn depth. This new modality of evaluation of burns seems to be an attractive proposal for quantitative classification, allowing proper choice of burn wound treatment: conservative or surgical, especially compared with static thermography. The work was an in vivo experiment on domestic pigs, and a small number of patients were also diagnosed as part of the study. Statistical analysis showed a high correlation between the ADT synthetic parameter--thermal time constant, τ--and the classification of burn wounds that were predicted to heal within 3 weeks and so were treated conservatively and those that were predicted to not heal within 3 weeks and so were surgically treated. The results of the study show an accuracy of 60.7% for clinical evaluation, 69.6% for static thermography, 83.0% for ADT, and 84.0% for histopathologic assessment. The authors have concluded that the ADT method with cold excitation is suitable for the qualitative and quantitative assessment of burn depth.

Photographic assessment of burn size and depth: reliability and validity

The aim of this study was to examine the reliability and validity of using photographs of burns to assess both burn size and depth. Fifty randomly selected photographs taken on day 0-1 post burn were assessed by seven burn experts and eight referring physicians. Inter-rater reliability in both groups (experts vs. referrers) was calculated. The validity of burn size assessment was calculated using live assessment as the gold standard, and of burn depth using clinical assessment in combination with laser Doppler imaging as the gold standard. The validity of the photographically-assessed indication for surgery was calculated using laser Doppler imaging and actual treatment as the gold standard. Finally, agreement in referral indication was calculated. Using photographs, burn size could be assessed reliably and validly by experts (ICCs of 0.83 and 0.87), but not by referrers (ICCs of 0.68 and 0.78). Photographic assessment of burn depth was neither reliable nor valid, with ICCs respectively of 0.38 and 0.28 for experts and 0.24 and 0.13 for referrers. The indication for surgery could also not be assessed validly. Agreement between assessors regarding referral indication was low. Burn size, but not burn depth, can be assessed reliably and validly by experts using photographs of the burn wound. We recommend exploring other forms of telemedicine, like live interactive video, to investigate whether this leads to an improved burn depth assessment where clinical assessment is not possible. There were no external sources of funding for this study. The authors have no conflicts of interest to declare with regard to the manuscript or its content.

The Assessment of Burn Depth by Laser Speckle Flowgraphy in Rats

The Assessment of Burn Depth by Laser Speckle Flowgraphy in Rats

Toward Targeted Early Burn Care

During the year 2011, a survey was performed to describe current practices throughout Europe regarding three critical issues of acute burn care, namely fluid resuscitation, nutrition, and burn wound excision strategy. Thirty-eight questionnaires returned by burn centres from 17 different European countries were analyzed. The survey shows that Parkland remains the most commonly used formula to determine fluid needs in adults. All respondent centers use urine output to guide fluid resuscitation. While early excision of deep burns is the rule among centers, burn depth assessment by laser Doppler imaging is used in only a few centers. Indirect calorimetry and Toronto formula to estimate energy requirements do not have unanimous backing from respondents. Current literature encourages clinicians to move forward targeted and individualized therapies using a bundle of basic and advanced hemodynamic parameters, indirect calorimetry, and laser Doppler imaging. The results of this study suggest that such an approach is not common yet, and reinforce the subsequent need for large clinical trials that would evaluate the impact of such guided therapies to provide recommendations with a significant level of evidence.

A comparative study of 1% silver sulphadiazine (Flammazine®) versus an enzyme alginogel (Flaminal®) in the treatment of partial thickness burns

IntroductionIn the conservative treatment of burns, rapid wound healing is desirable to obtain good a esthetic and functional results. The aim of this study was to compare the efficacy of 1% Silversulfadiazine (SSD/Flammazine®) and an enzyme alginogel (Flaminal® or Flaminal® Forte) on the healing of superficial and intermediate partial thickness burns. MethodsIn this retrospective cohort study comparable burn wounds treated with Flaminal® or with 1% SSD were included. Outcome parameters included: length of hospital stay, bacterial burden and time to wound closure. Significance was tested using SPSS package. Results44 wounds in the Flaminal® group, and 39 wounds in the 1% SSD group were included. Wounds treated with Flaminal® showed a significantly higher bacterial load (p=0.024) and contained significantly more bacterial species (p=0.010) but showed a significantly shorter healing time of 17 vs. 24 days (p<0.0001). ConclusionA significantly shorter healing time was demonstrated in partial thickness burn wounds treated with Flaminal® versus 1% SSD, which may lead to a shorter length of hospital stay and better scar quality. The possibility of accurate burn depth assessment and the results in this study corroborate the change in treatment protocol made in the year 2000 when we switched from 1% SSD to Flaminal®.

Cost-effectiveness of laser Doppler imaging in burn care in the Netherlands

BackgroundEarly accurate assessment of burn depth is important to determine the optimal treatment of burns. The method most used to determine burn depth is clinical assessment, which is the least expensive, but not the most accurate.Laser Doppler imaging (LDI) is a technique with which a more accurate (>95%) estimate of burn depth can be made by measuring the dermal perfusion. The actual effect on therapeutic decisions, clinical outcomes and the costs of the introduction of this device, however, are unknown. Before we decide to implement LDI in Dutch burn care, a study on the effectiveness and cost-effectiveness of LDI is necessary.Methods/designA multicenter randomised controlled trial will be conducted in the Dutch burn centres: Beverwijk, Groningen and Rotterdam. All patients treated as outpatient or admitted to a burn centre within 5 days post burn, with burns of indeterminate depth (burns not obviously superficial or full thickness) and a total body surface area burned of ≤ 20% are eligible. A total of 200 patients will be included. Burn depth will be diagnosed by both clinical assessment and laser Doppler imaging between 2–5 days post burn in all patients. Subsequently, patients are randomly divided in two groups: ‘new diagnostic strategy’ versus ‘current diagnostic strategy’. The results of the LDI-scan will only be provided to the treating clinician in the ‘new diagnostic strategy’ group. The main endpoint is the effect of LDI on wound healing time.In addition we measure: a) the effect of LDI on other patient outcomes (quality of life, scar quality), b) the effect of LDI on diagnostic and therapeutic decisions, and c) the effect of LDI on total (medical and non-medical) costs and cost-effectiveness.DiscussionThis trial will contribute to our current knowledge on the use of LDI in burn care and will provide evidence on its cost-effectiveness.Trial registrationNCT01489540

Acute Burn Care

After studying this article and accompanying Supplemental Digital Content, the participant should be able to: 1. Explain current burn-prevention strategies and criteria for referral to a burn center. 2. Summarize the current advances made in the critical care of acute burn patients. 3. Outline the recent developments in burn depth assessment and burn wound dressing technology. 4. Describe the common psychosocial aspects of postburn rehabilitation. Burn patients require interdisciplinary care in which the plastic surgeon plays a prominent role. Appropriate referral, assessment, treatment, and posttreatment supports are essential to achieving favorable outcomes following burn injury. The authors reviewed the current literature on epidemiology, prevention, referral criteria, critical care, wound assessment, wound dressings, and psychosocial aspects of burn injury. Recent advances in burn care are highlighted and have been made possible through ongoing collaborative epidemiologic, clinical, and basic biomedical research. A systematic interdisciplinary approach to the evaluation and treatment of acute burn injuries is pivotal to providing patients with the greatest chance of functional recovery. Plastic surgeons treating burn patients must remain current in a wide variety of areas, ranging from critical care to psychosocial rehabilitation.

Erythropoietin in the prevention of experimental burn progression

Damage control is essential in first aid of burn lesions. The aim of the present study was to investigate whether systemic erythropoietin (EPO) administration could prevent secondary burn progression in an experimental model. The burn comb model creates four rectangular burn surfaces intercalated by three unburned zones prone to progression. Twenty-one Wistar rats were randomized to a control group or to receive intraperitoneal EPO (500 units per kg) once a day for 5 days starting 45 min (EPO45min) or 6 h (EPO6h) after burn injury. Histological analyses assessing burn depth, inflammation and neoangiogenesis, planimetric evaluation of burn progression, and laser Doppler flowmetry to assess perfusion were performed after 1, 4 and 7 days. Final scarring time and contracture rate were assessed once a week. Burn progression was decreased significantly with EPO45min but not EPO6h; progression of burn depth stopped in the intermediate dermis (mean(s.e.m.) burn depth score 3·3(0·6) for EPO45min versus 4·7(0·3) and 5·0(0·0) for EPO6h and control respectively on day 7; P = 0·026) and the surface extension was significantly reduced (45(8), 65(4) and 78(4) respectively on day 7; P = 0·017). This was paralleled by faster re-establishment of perfusion with EPO45min (114(5) per cent on day 4 versus 85(6) and 91(3) per cent for EPO6h and control respectively; P = 0·096). The reduction in progression resulted in a decreased healing time (7·3(0·7) weeks for EPO45min versus 11·5(1·0) and 10·8(0·5) weeks for EPO6h and control; P = 0·020) and contracture rate (P = 0·024). Early EPO prevented burn progression, mainly by improved vascular perfusion.

A pilot evaluation study of high resolution digital thermal imaging in the assessment of burn depth

Thermal imaging is a tool that can be used to determine burn depth. We have revisited the use of this technology in the assessment of burns and aim to establish if high resolution, real-time technology can be practically used in conjunction with clinical examination to determine burn depth. 11 patients with burns affecting upper and lower limbs and the anterior and posterior trunk were included in this study. Digital and thermal images were recorded at between 42h and 5days post burn. When compared to skin temperature, full thickness burns were significantly cooler (p<0.001), as were deep partial thickness burns (p<0.05). Superficial partial thickness burns were not significantly different in temperature than non-burnt skin (p>0.05). Typically, full thickness burns were 2.3°C cooler than non-burnt skin; deep partial thickness burns were 1.2°C cooler than non-burnt skin; whilst superficial burns were only 0.1°C cooler. Thermal imaging can correctly determine difference in burn depth. The thermal camera produces images of high resolution and is quick and easy to use.