Development of Noninvasive and Quantitative Methodologies for the Assessment of Chronic Ulcers and Scars in Humans

Abstract

Chronic ulcers are a significant and common cause of morbidity and mortality worldwide. They disrupt the epidermis and dermis, resulting in a loss of barrier function. Keloids and hypertrophic scars (benign cutaneous tumors) represent an abnormal healing response. These fibroproliferative disorders are characterized by an overabundance of collagen and accumulation of extracellular matrix due to an imbalance between synthesis and degradation, culminating in excessive scarring. The objectives of this study were to evaluate and compare noninvasive biophysical methods for the measurement of outstanding quantitative parameters of scars and chronic ulcers, and to establish correlations between the parameters measured and the results of conventional subjective clinical evaluations. The development of new technologies, based on ultrasonography and laser Doppler, makes possible new dermatological evaluation methods. Fifteen patients (6 females and 9 males) with 15 chronic ulcers (4 diabetic ulcers, 10 venous ulcers and 1 pressure ulcer) and 30 patients (19 females and 11 males) with 30 scars (25 hypertrophic and 5 keloids) were included in this study. Clinical evaluation was performed by a dermatologist, an aesthetic surgeon and an endocrinologist. Biophysical measurements were used to assess local blood flow by laser Doppler flowmetry (Moor DRT4), thickness and echogenicity by high frequency ultrasonography (20 MHz, Dermascan C) and ulcer linear dimensions by image analysis. Our results show that blood flow within the ulcers and scars was higher than within normal skin. Also, skin thickness of chronic ulcers was decreased when compared to normal skin; the thickness of hypertrophic scars, but not of keloids, was increased in comparison to normal skin, and presented the possibility of measuring wound and scar surfaces with precision. In summary, this pilot study established the feasibility of measuring various biophysical parameters and adapted their potential utility to research on wounds.

Skin Blood Flow in Diabetic Dermopathy

“…Other investigators have documented that blood flow is increased in hypertrophic but not atrophic scars. [22][23][24] These results suggest that diabetic dermopathy lesions are, in fact, scars. Patients typically ascribe their dermopathy lesions to prior trauma.…”

High-Frequency Ultrasound: Obtaining Optimal Images and the Effect of Image Artifacts on Image Quality

“…Recently, high-frequency ultrasound (HFUS) using a 20 megahertz (MHz) probe has been used to provide computer-generated images for both dermatologic diagnostics and research to evaluate lymph nodes, 7 chronic injuries, 8,9 skin lesions, and tumors. 7,[10][11][12] However, the use of 20 MHz HFUS to investigate the development of PrIns is relatively new.…”

“…[13][14][15] The hypoechogenic areas are thought to reflect increasing fluid content associated with inflammation indicating soft tissue edema before visible damage is noted at the skin surface. 8,10,[13][14][15][16][17][18] HFUS was validated as a sensitive method for changes in dermal hydration associated with edema formation by nuclear magnetic resonance imaging. 19 In the acute care setting, HFUS may be used for documentation, detection, and monitoring of soft tissue injury in patients at risk upon hospital or long-term care admission; however, little is known regarding its accuracy or reliability.…”

The Characteristics of Blood Supply and Tissue Hypoxia in Pathological Scars

“…10 Timar-Banu et al used LDF technique and found that, the blood flow in pathological scars was greater than that in normal skin. 18 Qingliang Liu et al used LSCI technique and found that the blood flow in the adjacent skin surrounding keloid tissues was greater than that in nonadjacent skin tissues. 15 Blood flow also changes with the progression of pathological scars.…”

“…15 Blood flow also changes with the progression of pathological scars. Ehrlich's study showed that, at [16][17][18] weeks after wound closure, the blood flow in hypertrophic scars was still three times higher than in normal skin and four times greater than in normal scars. …”