Depth Of Blood Vessels Research Articles

Method for measuring blood flow and depth of blood vessel based on laser speckle contrast imaging using 3D convolutional neural network: A preliminary study

Laser speckle contrast imaging (LSCI) is a technology that can acquire real-time two-dimensional perfusion images non-invasively. However, measuring perfusion velocity under a tissue is difficult due to its optical properties. Dynamic scattered light occurs by perfusion is diffused by the surrounding tissue and it depends on the depth of tissue. We aimed to develop a three-dimensional convolutional neural network (3D-CNN) model based on laser speckle contrast images to measure the flow velocity and the depth of tissue using a flow phantom. The training data was selected as a region containing both static speckles and dynamic speckles, and the model was trained on the laser speckle contrast image data. The trained model showed a measurement accuracy of more than 90 % for velocity and 99 % for depth measurement. This study has the potential of a deep-learning model based on LSCI to analyze the blood flow and depth of blood vessels in bio-applications.

Superficial Intramuscular Gluteal Lipograft by Doppler Ultrasound: A Report of 24 Patients.

Gluteal fat grafting is a common procedure in liposculpture. This study proposes a Doppler ultrasound-guided intramuscular and subcutaneous gluteal lipotransfer technique that allows for visualization of the location of the gluteal vessels, avoiding approaching them during lipotransfer by having the cannula localized during fat infiltration. This new technique was applied to 24 women after obtaining informed consent and providing them with a clear explanation of potential risks and complications. Doppler ultrasound was used to locate the site and depth of blood vessels, and for quadrant scanning of vessels and superficial intramuscular visualization of the cannula's location. Intramuscular lipotransfer was performed with a volume of 400 mL per gluteus (or less), and 12 patients underwent magnetic resonance imaging before and 3 months after surgery. This technique allowed for visualizing the location of the gluteal vessels, and infiltration could be easily performed in patients. In the 24 glutei reviewed postsurgery, from 12 patients who underwent pre- and postsurgery magnetic resonance imaging, intramuscular fat was found; however, there was no migration outside the gluteus maximus muscle. No local or systemic complications were observed. The results of our report show that fat filtration did not migrate outside the gluteus maximus muscle. This finding seeks to promote new research to create theoretical/practical precedents for the intervention of plastic surgeons and, from there, promote the standardization of a new and safe technique.

An inversion approach for non-invasive detection of subcutaneous structure and temperature based on 1D residual neural network

Laser skin dermatology has attracted increasing attention with awareness of the aesthetic sense. Real-time detection of subcutaneous vessel temperature and structure during laser treatment is essential for efficacy and safety of surgery. By using 1D residual neural network to improve the accuracy of feature extraction, an inverse method model with outstanding reconstruction performance and noise insensitivity was proposed to estimate vascular parameters including temperature, depth and diameter of blood vessel. The network established an end-to-end mapping of the time-dependent skin surface temperature after short-pulse laser irradiation to the temperature gradient along the skin depth, allowing vascular parameters to be extracted directly from the observed data measured by the infrared camera. The model trained by data containing noise of multiple intensities could identify and attenuate noise in the original data, which is beneficial to suppress the broadening effect of a significant broadening of reconstructed temperature peaks induced by noise and significantly improve the reconstruction accuracy of less than 5%. In comparison with traditional iterative methods, the new model shows technical superiority in its unparalleled accuracy and low computational cost as well as great potential for real-time monitoring of subcutaneous vascular features.

Rapid and non-invasive detection of high-thickness glucose solution concentrations using quantum cascade laser-based transmission infrared spectroscopy

Most existing spectroscopic methods measure the concentration of blood glucose using attenuated total reflection. However, the short penetration depth (in the range of 2–15 μm) is a severe limitation. In practice, this approach is difficult to use because the depth of blood vessels in the skin exceeds 0.2 mm. As a solution, this work introduces a transmission spectroscopic method to measure the concentration of glucose. A fast infrared spectroscopic glucose concentration measurement method using a mid-infrared wavelength-swept pulsed quantum cascade laser (QCL) is adopted. This method employs a transmission optics system that does not require complicated adjustments or maintenance, together with an asynchronous signal method developed to shorten the measurement time. The combination of the high power of the QCL with the proposed algorithm enables measurements of glucose solution samples with an optical path length of 0.2 mm, which is sufficient for obtaining absorbance spectra and calculating the concentration of glucose in these samples. A linear regression of the average absorbance of the different glucose concentrations yields R2 values as high as 0.999. Moreover, using the asynchronous signal–based method reduces the single measurement time to 20 ms, and a 30 × integration required only 0.6 s. The proposed transmission method not only enables detection on the skin but also exhibits potential for measuring tear film on the eyeball in the tangential direction. This has potential applications in the diagnosis and management of diabetes.

Ultrasonography-Guided Cannula Method for PMMA Injection in Aesthetic Gluteal Augmentation: A Technical Note

Purpose: Revolumization with deep injections has become increasingly common, even in high-risk areas for intravascular infusion or nerve injury. This study aimed to assess the usefulness of the ultrasonography-guided cannula method for preventing side effects during the injection of polymethylmethacrylate (PMMA) fillers. Real-time ultrasonography was used to monitor the injection of PMMA as a filler in the gluteus for aesthetic purposes. This way, adjacent anatomical structures such as arteries, veins, and nerves could be seen during the whole procedure. Materials and Methods: This study describes the technique used for ultrasound-guided injections of PMMA in the gluteal region of two patients. Patients 1 and 2 were injected with 300 mL and 220 mL of the filler, respectively. Injections were administered intramuscularly and subcutaneously into sites that had been marked before the procedure. While one professional performed the injections, another guided them with real-time ultrasound imaging, using the same equipment for both patients. The location and depth of blood vessels and nerves were determined before the procedure, and the insertion of the cannula was accompanied by ultrasound imaging. Results: The PMMA filler, as well as the cannula, blood vessels, and nerves, was visualized using ultrasound. Some differences were observed between the cases. In the first patient, a small amount of PMMA from a previous procedure could be found (hyperechoic images), while the second one had had no filler injection before. Conclusion: Based on these cases, ultrasonography can be seen as a complementary tool to monitor tissue filler injections, especially in the gluteal region, thus, avoiding possible vascular and nervous injuries. Real-time ultrasound makes the procedure safer, protecting regional structures from lesions. The ultrasonography-guided method succeeded in localizing the cannula, blood vessels, and the sciatic nerve, allowing for safe injection of PPMA filler into a deep gluteal region.

Combined Monte Carlo and k-Wave Simulations for Reconstruction of Blood Oxygen Saturation in Optoacoustics: A Pilot Study

Optoacoustic (OA) imaging of biological tissues is a modern technique allowing for three-dimensional blood oxygen saturation mapping based on OA spectroscopy data. Since biological tissues are optically inhomogeneous and the spatial distribution of optical parameters within a biological tissue is a priori unknown, Monte Carlo simulation technique is traditionally used to estimate the distribution of probing illumination within tissues in quantitative OA reconstruction. Currently, machine learning techniques are actively employed for reconstructing 3D distribution of blood oxygen saturation or estimating optical properties of biological tissues based on training datasets. In this paper, systemic calculations of synthetic OA images of a medium with embedded vessel-like structures were performed to create a training dataset for machine learning employing combined application of the Monte Carlo technique for direct solution of optical problem and difference-space pseudo-spectral approach implemented through k-Wave Toolbox calculations for the acoustical part. The calculations were performed for probing wavelengths of 532 nm, 658 nm and 1064 nm, which are commonly employed in spectral OA imaging. Simulated OA data for different orientation, diameter and embedding depth of blood vessels allows analyzing the effect of these parameters on the formation of OA image and the reconstruction of blood oxygen saturation. The ratio of OA signals corresponding to probing wavelengths of 658 nm and 1064 nm was employed for simple reconstruction of blood oxygen saturation in silico for different vessel geometries with the precision of < 3–15% for the most of blood vessels diameters and embedding depths and the range of blood oxygen saturation values ≥ 0.8. The obtained set of synthetic OA data has high potential as a training set for employment in machine learning techniques aiming at mapping blood oxygenation based on spectral OA data.

THE COMPLEX STUDY OF GINGIVAL MICROVESSELS IN YOUNG PEOPLE

Morphological and functional features of tissue blood flow are genetically determined, the identification of individual characteristics of microcirculation in the oral mucosa in the gum area can help determine the specifics of periodontal tissue damage in various patients. The aim of the study was to study tissue blood flow and microvessels in different areas of the oral mucosa in young people. In 40 healthy young people, biomicroscopy and laser Doppler flowmetry were used to record blood microcirculation indicators in various parts of the gums in the upper and lower jaws. On cadaveric material, the depth of blood vessels in different parts of the gum was studied. As a result of the study, it was found that the density of microvessels and the intensity of blood flow decrease with distance from the transitional fold to the edge of the gum. In the same areas of the mucous membrane in the upper and lower jaws, the microcirculation indicators do not differ. The most common (in 35 out of 40 subjects) in the vessels of the oral mucosa was the mesoemic type of blood microcirculation, in which the tissue blood flow was of medium intensity and the mechanisms of its regulation were balanced. In other cases, very low (hypoemic type) or high (hyperemic type) indicators of tissue blood flow with weak activity of vasomotor mechanisms of regulation of the state of microvessels of the oral mucosa were recorded. Thus, the use of a set of methods for studying the microvasculature of the oral mucosa in the gingival region allows us to quantitatively characterize the state of microvessels, as well as the intensity of tissue blood flow in different parts of the gingiva of the upper and lower jaws in young people. The richest microvascular network is observed in the region of the transitional gingival fold. As the distance from the transitional fold to the marginal part of the gums, the density of capillaries and the intensity of blood flow in them decrease, the gingival mucosa near the neck of the tooth has the lowest microcirculation rates.

Numerical Modeling of The Dysplastic Vessel Heating in PWS by Yellow 578 nm Copper Vapor Laser Radiation for Different Skin Phototypes.

Introduction: Many clinical studies and protocols have been written about laser treatment for fair skin phototypes. However, for dark-skinned phototypes, information is limited, and the risk of burns is higher, especially if the same settings are recommended for fair skin. Competitive epidermal melanin absorption decreases the light energy reaching dysplastic vessels in a port-wine stain (PWS), preventing the vessel from achieving the temperature of the desired clinical result. Therefore, the choice of safe laser settings for different skin phototypes can be realized using numerical modeling of PWS vessel heating. This study aimed to demonstrate the algorithm for choosing both effective and safe photodestruction of dilated dermal vessels in PWS with the copper vapor laser (CVL) at 578 nm for different skin phototypes. Methods: We used the multilayered skin model with different melanin content for detecting the safe laser parameters for PWS treatment. The calculation of the selective heating of the vascular component with CVL radiation at yellow 578-nm wavelengths for different skin phototypes was performed via Matlab mathematical programming system and its application Femlab for solving partial differential equations using the Finite element method. Results: We determined the location, depth, and size of blood vessels that could be selectively heated to coagulation temperature for different skin prototypes. CVL fluence values need to be reduced almost two times for skin phototype IV than for skin phototype II to provide safe CVL treatment. The maximum depth of the location of the vessels, which can be selectively heated to coagulation temperature, also decreased for dark skin phototypes. Histological and histochemical findings validated the results of our calculations. Conclusion: To our knowledge, the use of numerical simulation to optimize has not yet been considered. According to our calculations, CVL could selectively heat the dilated vessel, which occurred in purple and proliferative-type PWS for dark skin at the reduced fluence range and depth.

Thermomechanical Modeling of Laser Ablation Therapy of Tumors: Sensitivity Analysis and Optimization of Influential Variables.

In cancer treatment, laser ablation is a promising technique used to induce localized thermal damage. Different variables influence the temperature distribution in the tissue and the resulting therapy efficacy; thus, the optimal therapy settings are required for obtaining the desired clinical outcome. In this work, thermomechanical modeling of contactless laser ablation was implemented to analyze the sensitivity of independent variables on the optimal treatment conditions. The Finite Element Method was utilized to solve the governing equations, i.e., the bioheat, mechanical deformation, and the Navier-Stokes equations. Validation of the model was performed by comparing experimental and simulated temperatures, which indicated high accuracy for estimating temperature. In particular, the results showed that the model can estimate temperature with a good correlation factor (R = 0.98) and low Mean Absolute Error (3.9 °C). A sensitivity analysis based on laser irradiation time, power, beam distribution, and the blood vessel depth on temperature distribution and fraction of necrotic tissue was performed. An optimization process was performed based on the most significant variables, i.e., laser irradiation time and power. This resulted in an indication of the optimal therapy settings for achieving maximum procedure efficiency i.e., the required fraction of necrotic tissue within the target volume, constituted by tumor and safety margins around it.

Wavelength optimization for the laser treatment of port wine stains

Based on the well-known principle of selective photothermolysis, laser has been a promising way for the treatment of port wine stains (PWSs). The laser wavelengths used for PWS's clinical treatment include but are not limited to pulsed dye laser (PDL) in 585-600nm, long-pulse 755-nm alexandrite, and 1064-nm Nd:YAG lasers. The objective of this study was to investigate the optimal wavelength for PWS's laser treatment. A two-scale mathematic model was constructed to simultaneously quantify macroscale laser energy attenuation in two-layered bulk skin and microscale local energy absorption on target blood vessels within Krogh unit. The effects of morphological parameters, including epidermal melanin content, epidermal thickness, dermal blood content, blood vessel depth, and diameter on laser energy deposition within target blood vessels, were investigated from the visible to near-infrared bands (500-1100nm). The energy deposition ratio of target blood vessel to epidermal surface was proposed to determine the optimal laser wavelength for PWS with different skin morphological parameters. The bioheat transfer modeling and animal experiment are also conducted to prove our wavelength optimization. The optimal wavelengths for lightly pigmented skin with small and shallow target blood vessels are 580-610nm in the visible band. This wavelength coincides with commercially used PDL. The optimal wavelength shifts to 940nm as the epidermal pigmentation increases or the size and blood vessel depth increases. The optimal wavelength changes to 1005nm as the epidermal pigmentation or the size and burying depth of target blood vessel further increases. Nine hundred forty nanometers can be selected as a general wavelength in PWS treatment to meet the need in most widely morphological structure. Lasers with wavelengths in the 580-610, 940, and 1005nm regions are effective for treating PWS because of their high optical selectivity in blood over the epidermis.

Optical coherence tomography quantifying photo aging: skin microvasculature depth, epidermal thickness and UV exposure.

Photo aging predominantly occurs in the face, neck and hands due to UVA and UVB irradiation. It is associated with skin cancer and histological studies indicate thinning of the epidermis and elastosis occurs. Dynamic Optical coherence tomography (D-OCT) is a non-invasive imaging tool able to visualize the epidermis and upper dermis and its blood vessels as well as to evaluate epidermal thickness (ET) and blood flow. To investigate ET and blood vessel depth using D-OCT in human subjects correlated to UV exposure. We evaluated data from 249 healthy adults, that had D-OCT-scans conducted at four different regions (forehead, neck, arm and hand) and correlated ET and blood vessel depth with occupational UV exposure (total standard erythema dose, Total SED), season and demographic data. Regional differences in ET and blood vessel depth were found (p values < 0.001). Multiple linear regressions showed a seasonal effect on both ET (- 0.113 to - 0.288µm/day, p values < 0.001) and blood vessel depth (0.168-0.347µm/day, p values < 0.001-0.007) during August-December. Significant age-related decrease of ET was seen in forehead, arm and hand (0.207-0.328µm/year, p values = 0.002-0.18) and blood vessel depth in forehead (0.064-0.553µm/year, p values = 0.01-0.61). Males had thicker epidermis (3.92-10.93µm, p values = 0.002-0.15). Changing seasons are a major predictor of both ET and blood vessel depth, showing strongest effect in non-exposed areas, suggesting a systemic effect, possibly due to seasonal vitamin D fluctuation. Sex, age and occupational UV exposure affect ET. This study demonstrated the feasibility of D-OCT to evaluate epidermal thickness and blood vessel depth.

A detailed comparison between the endoscopic images using blue laser imaging and three-dimensional reconstructed pathological images of colonic lesions.

Blue laser/light imaging (BLI) is an image-enhanced endoscopy (IEE) technique that can provide an accurate diagnosis by closely observing the surface structure of various colonic lesions. However, complete correspondence between endoscopic images and pathological images has not been demonstrated. The aim of this study was to accurately compare endoscopic images and the pathological images using a three-dimensionally (3D) reconstructed pathological model. Continuous thin layer sections were prepared from colonic tissue specimens and immunohistochemically stained for CD34 and CAM5.2. Three-dimensional reconstructed images were created by superimposing immunohistochemically stained pathological images. The endoscopic image with magnifying BLI was compared with the top view of the 3D reconstructed image to identify any one-to-one correspondence between the endoscopic images and histopathological images using the gland orifices and microvessels as a guide.Using 3D reconstructed pathological images, we were able to identify the location on the endoscope image in cases of colonic adenocarcinoma, adenoma and normal mucosa. As a result, the horizontal plane of the endoscopic image and the vertical plane of the 2D pathological specimen were able to be compared, and we successfully determined the visible blood vessel depth and performed a detailed evaluation on magnifying BLI. Examples are as follows: (1) The median vasculature depth from the mucosal surface that could be recognized as vasculature on magnifying BLI was 29.4 μm. The median depth of unrecognizable vessels on magnifying BLI was 218.8 μm, which was significantly deeper than recognizable vessels. (2) Some brownish structures were suggested to potentially be not only dense vessels, vessel expansions, corrupted vessels but also bleeding or extravasation of erythrocytes. Overall, we demonstrated a new approach to matching endoscopic images and pathological findings using a 3D-reconstructed pathological model immunohistochemically stained for CD34 and CAM5.2. This approach may increase the overall understanding of endoscopic images and positively contribute to making more accurate endoscopic diagnoses.

93 Optical Coherence Tomography: A New Imaging Technique for Burn Injuries

Abstract Introduction Accurate assessment of burn depth and healing time remains elusive. As a result, some patients may wait weeks, through painful wound care only to have surgery. Others may have early surgery on wounds that may have healed with a good outcome. Expert opinion remains the most common method of wound evaluation. We sought to evaluate if Optical Coherence Tomography (OCT) with Microangiography (OMAG) can predict burn wound healing. Methods We prospectively enrolled a cohort of 17 burned subjects whose attending physician initially evaluated the depth of the wound as indeterminate. Burn wounds were scanned on enrollment and weekly, until healed or grafted, using a clinical prototype swept source OCT with OMAG capability. Wounds were also assessed by the attending physician for depth of injury and healing time. Wounds were photographed at the time of each scan. OCT and OMAG scans were then used to quantitatively determine blood vessel depth and density within the wound. Univariate regression with clustering and panel effects evaluated the association with healing time. Photographs and scans of each wound from all time points were evaluated by 5 blinded assessors (four surgeons and an OCT engineer) for time to wound healing. Kappa was used to measure the interrater reliability between evaluators. Results The mean patient age was 46 years with a mean burn size of 10% body surface area. Fourteen patients ultimately healed their wounds. Three patients underwent excision and grafting. There was no significant association between vessel depth or density and healing time (Table). Similarly, vessel depth was not predictive of the need for surgery. However, vessel density £ 0.255 perfectly predicted the need for surgery. There was no agreement between evaluators regarding predicted healing looking at OCT and OMAG scans (Kappa 0.003). There was moderate agreement between evaluators predicting healing from photos (Kappa 0.047). Conclusions This preliminary data demonstrates that quantitative OCT/OMAG data shows promise in predicting which patients undergo surgical therapy. Variation of healing estimates from provider image assessment support the best use of this tool as a quantitative measure. Larger studies are needed to explore these findings and the role of this technology. Applicability of Research to Practice OCT/OMAG is a quantitative tool that shows promise in predicting which patients undergo surgical therapy.

Endocytoscopy with NBI has the potential to correctly diagnose diminutive colorectal polyps that are difficult to diagnose using conventional NBI.

Background and study aims Real-time diagnosis of colorectal polyps is needed to prevent unnecessary resection of benign polyps. The vessels in hyperplastic polyps sometimes mimic the characteristic meshed capillary network of neoplastic lesions on non-magnified narrow-band imaging (NBI). Endocytoscopy in conjunction with NBI (EC-NBI) enables more detailed vessel observation. The current study evaluated whether EC-NBI can accurately diagnose small colorectal lesions with visible vessels on non-magnified NBI. Patients and methods This retrospective study was conducted from January to December 2016. During colonoscopy, lesion images were obtained using NBI and EC-NBI. On EC-NBI, lesions were classified as having “clear,” “unclear,” or “invisible” blood vessel margins. All specimens were resected and pathologically examined, and the association between vessel margin findings and pathological diagnosis was assessed. The lesion surface to vessel depth was measured in clear, unclear, and invisible lesions. Results Among 114 adenomas, 108 were clear, while six were unclear. Among 36 hyperplastic polyps, eight were clear, while 28 were unclear. A micro-network (MN) pattern was seen in 106 of 114 adenomas, and four of 36 hyperplastic polyps. The sensitivity, specificity, correct diagnostic rate, and positive and negative predictive values of clear blood vessel margins or a MN pattern as an adenoma index were 98.2 %, 69.4 %, 91.3 %, 91.1 %, and 92.6 %, respectively. EC-NBI correctly diagnosed 69.4 % (25/36) of hyperplastic polyps. The lesion surface–blood vessel distance was greater in unclear versus clear lesions ( P < 0.001), and invisible versus unclear lesions ( P < 0.001). Conclusions EC-NBI may effectively differentiate hyperplastic polyps with visible vessels from adenomas. Blood vessel depth affects visibility.

Investigating the influence of blood-vessel depth and sensor location on the light-tissue interactions using a Monte Carlo model

A three-dimensional Monte Carlo model of light tissue interactions with a slab of fat tissue having a cylindrical blood vessel is presented. The model has been explored at an optical wavelength of 660 nm and simulations have been carried out to investigate the influence of – 1) vessel depths and b) sensor location on the associated light-tissue interactions. Such investigation will be immensely useful to design a wearable sensing technology and predicting the sensor outcomes.

Minimally invasive treatment for osteonecrosis of the femoral head in ARCO stage Ⅱ and Ⅲ with bioceramic system

To perfect the theory system of minimally invasive treatment for osteonecrosis of the femoral head (ONFH) with β tricalcium phosphate (β-TCP) bioceramic system and evaluate the effectiveness. Eighteen New Zealand white rabbits aged 7-8 months were used to establish an animal model to verify the vascularization of porous β-TCP bioceramic rods. Micro-CT based three-dimensional reconstruction and fluorescence imaging were used to display the new blood vessels at 4, 8, and 12 weeks after operation. The inserting depth, number and diameter of vessels in the encapsulated area were analyzed. Nine pig femoral specimens were randomly divided into 3 groups ( n=3): group A was normal femur; group B had cavity (core decompression channel+spherical bone defect in femoral head); in group C, mixed bioceramic granules were implanted to fill the defect in femoral head, and porous β-TCP bioceramic rod was implanted into decompression channel. The stiffness and yield load of specimens were analyzed by biomechanical test. A multicenter retrospective study was conducted to analyze 200 patients (232 hips) with femoral head necrosis treated with bioceramic system in 7 hospitals in China between January 2012 and July 2018. There were 145 males and 55 females, with an average age of 42 years (range, 17-76 years). According to the Association Research Circulation Osseous (ARCO) stage, 150 hips were in stage Ⅱ and 82 hips in stage Ⅲ. Postoperative imaging assessment was carried out regularly, and hip function was evaluated by Harris score. The effectiveness of ARCO stage Ⅱ and Ⅲ was also compared. Animal experiments showed that blood vessels could grow into the encapsulated area and penetrate it at 12 weeks. The inserting depth, number and diameter of blood vessels in the encapsulated area gradually increased, and there was significant difference between different time points ( P<0.05). Biomechanical tests showed that the stiffness and yield load of specimens in groups B and C were significantly lower than those in group A, while the yield load in group B were significantly lower than that in group C ( P<0.05). The stiffness in group C was restored to 41.52%±3.96% in group A, and the yield load was restored to 46.14%±7.85%. Clinical study showed that 200 patients were followed up 6-73 months, with an average of 22.7 months. At last follow-up, 12 patients (16 hips) underwent total hip arthroplasty, and the hip survival rate was 93.10%. According to the imaging evaluation, 184 hips (79.31%) were stable and 48 (20.69%) were worse. Harris score (79.3±17.3) was significantly higher than that before operation (57.3±12.0) ( t=18.600, P=0.000). The excellent rate of hip function was 64.22% (149/232). The survival rate of hip joint, imaging score and Harris score of patients in ARCO stage Ⅱ were better than those in ARCO stage Ⅲ ( P<0.05). β-TCP bioceramic system can guide the abundant blood supply of greater trochanter and femoral neck to the femoral head to promote repair; it can partly restore the mechanical properties of the femoral head and neck in the early stage, providing a new minimally invasive hip-preserving method for patients with ONFH, especially for those in early stage.

Characterization of Laser-Resistant Port Wine Stain Blood Vessels Using In Vivo Reflectance Confocal Microscopy.

Port wine stain (PWS) is a congenital vascular malformation of the human skin. Laser is the treatment of choice for PWS. Laser-resistant PWS is one crucial factor accounting for inadequate treatment outcome, which needs to be fully characterized. This study aims to quantitatively characterize the morphology of laser-resistant PWS blood vessels in the upper papillary dermis using in vivo reflectance confocal microscopy (RCM). A total of 42 PWS subjects receiving laser treatment from August 2016 through July 2018 were enrolled into this study. Thirty-three subjects had facial PWS; nine had extremity PWS. All subject's PWS received multiplex 585/1,064 nm laser treatment. RCM images were taken before and after treatment. The density, diameter, blood flow, and depth of PWS blood vessels were analyzed. We found 44.4% PWS on the extremities (four out of nine subjects) were laser-resistant, which was significantly higher (P < 0.001) when compared with those PWS on the face (15.2%, 5 out of 33 subjects). The laser-resistant facial PWS blood vessels had significantly higher blood flow (1.35 ± 0.26 U vs. 0.89 ± 0.22 U, P < 0.001), larger blood vessel diameters (109.60 ± 18.24 µm vs. 84.36 ± 24.04 µm, P = 0.033) and were located deeper in the skin (106.01 ± 13.87 µm vs. 87.82 ± 12.57 µm, P < 0.001) in the skin when compared with laser-responsive PWS on the face. The average PWS blood vessel density (17.01 ± 4.63/mm2 vs. 16.61 ± 4.44/mm2 , P = 0.857) was not correlated to the laser resistance. Laser-resistant PWS blood vessels had significantly higher blood flow, larger diameters, and were located deeper in the skin. RCM can be a valuable tool for a prognostic evaluation on laser-resistant lesions before treatment, thereby providing guidance for tailored laser treatment protocols, which may improve the therapeutic outcome. The limitations for this study include relative small sample size and acquisitions of different blood vessels before and after 2 months of treatment. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Optical coherence tomography correlates multiple measures of tissue damage following acute burn injury.

The visual assessment of burned skin is inherently subjective, and whilst a number of imaging modalities have identified quantifiable parameters to characterize vascular and structural changes following burn damage, none have become common place in the assessment protocol. Here, we use optical coherence tomography (OCT)-based angiography (OCTA) to introduce novel correlations between vessel depth, i.e., the depth of functional blood vessels beneath the tissue surface, edema depth, i.e., the depth of interstitial fluid buildup beneath the tissue surface, and tissue injury depth, i.e., the depth of collagen denaturation beneath the tissue surface, following burn injury. A clinical prototype OCT system was used to collect OCT images from various sites of burned skin in patients. Optical microangiography (OMAG) algorithm was used to derive OCTA information from the acquired OCT images, from which the presence of blood vessels and edema were detected. The optical attenuation mapping of structural OCT information was used to detect tissue injury depth. The depths of vessel, edema and tissue injury were measured using a semi-automatic segmentation algorithm. Correlation analysis was performed using a Pearson correlation coefficient using one-tailed analysis with significance being established by a P value ≤0.05. Four burn patients were recruited and scanned at multiple sites using the prototype system within 3-6 days of injury. Approximate measurements include a vessel depth range of 320-1,360 µm, an edema depth range of 0-400 µm, and a tissue injury depth range of 130-420 µm. Correlations were subsequently observed between vessel depth and edema depth (r=0.8521, P=0.0001), and vessel depth and tissue injury depth (r=0.6296, P=0.0106). OCT is feasible to provide the critical information of vessel depth, edema depth, and tissue injury depth of skin burns, which may represent viable assessment criteria for the characterization of cutaneous burns in future.

Relations of Blood Vessel Depth and Vascular Area Based on a History of Failed Blood Draws Among Female College Students

Relations of Blood Vessel Depth and Vascular Area Based on a History of Failed Blood Draws Among Female College Students

Photothermal treatment of port-wine stains using erythrocyte-derived particles doped with indocyanine green: a theoretical study.

.Pulsed dye laser irradiation in the wavelength range of 585 to 600 nm is currently the gold standard for treatment of port-wine stains (PWSs). However, this treatment method is often ineffective for deeply seated blood vessels and in individuals with moderate to heavy pigmentation. Use of optical particles doped with the FDA-approved near-infrared (NIR) absorber, indocyanine green (ICG), can potentially provide an effective method to overcome these limitations. Herein, we theoretically investigate the effectiveness of particles derived from erythrocytes, which contain ICG, in mediating photothermal destruction of PWS blood vessels. We refer to these particles as NIR erythrocyte-derived transducers (NETs). Our theoretical model consists of a Monte Carlo algorithm to estimate the volumetric energy deposition, a finite elements approach to solve the heat diffusion equation, and a damage integral based on an Arrhenius relationship to quantify tissue damage. The model geometries include simulated PWS blood vessels as well as actual human PWS blood vessels plexus obtained by the optical coherence tomography. Our simulation results indicate that blood vessels containing micron- or nano-sized NETs and irradiated at 755 nm have higher levels of photothermal damage as compared to blood vessels without NETs irradiated at 585 nm. Blood vessels containing micron-sized NETs also showed higher photothermal damage than blood vessels containing nano-sized NETs. The theoretical model presented can be used in guiding the fabrication of NETs with patient-specific optical properties to allow for personalized treatment based on the depth and size of blood vessels as well as the pigmentation of the individual’s skin.