High-frequency Ultrasound Measurements Research Articles

In vivo evaluation of topical ascorbic acid application on skin aging by 50MHz ultrasound.

Ascorbic acid (AA) is a powerful antioxidant capable of acting significantly both in the prevention and treatment of the skin aging process. One way to assess the in vivo efficacy of anti-aging treatments is by using the high-frequency ultrasound (HFUS) skin image analysis technique, a non-invasive approach that allows for a new level of evaluating the effectiveness of dermatological and cosmetic products. The aim of the present study was to assess the performance of a topical emulsion of liquid crystalline structures containing AA using the 50MHz HFUS skin image analysis method. Twenty-five healthy female participants between 35 and 60years were included, all of whom randomly applied a placebo formulation and an AA-containing formulation to each forearm, once a day, for 30days. HFUS measurements were performed before using the products (T0), 2h later (T2h), and after 30days of use (T30d). The analyzed parameters included total skin, dermal, and epidermal echogenicity; variation and mean thickness of total skin, the epidermis and dermis; and surface roughness. Statistical analyses were performed using the Friedman test, followed by Dunn's test for comparisons of multiple means (α=0.05). A significant increase in total skin and dermal echogenicity was observed after topical AA application. Our findings suggest that collagen synthesis significantly increased after topical therapy with AA, which was responsible for the increment in dermal echogenicity. This study showed, through the HFUS technique, that the topical use of AA promoted dermal redensification after 30days of application.

Morphologic Features of Cutaneous T-Cell Lymphomas Using Dermoscopy and High Frequency Ultrasound.

The diagnosis of cutaneous T-cell lymphomas (CTCL) is frequently delayed by a median of three years and requires the clinical evaluation of an experienced dermatologist and a confirmatory skin biopsy. Dermoscopy and high-frequency ultrasound (HFUS) represent two non-invasive diagnostic tools. While dermoscopy is inexpensive and widely used for the diagnosis of melanoma and non-melanoma skin cancers, HFUS of skin lymphomas represents a novel diagnostic approach that is not yet implemented in the routine dermatologic practice. The aim of our study was to prospectively assess skin lesions of patients with either CTCL patches or plaques with dermoscopy and HFUS and to compare the findings with atopic dermatitis (AD) and psoriasis. Thirteen patients with an established diagnosis of CTCL, psoriasis, or AD were studied: Dermoscopy features including spermatozoa-like structures and the presence of white scales could assist in differentiating between early-stage CTCL and AD. HFUS measurements of the skin thickness indicated increased epidermal-, thickness in CTCL, and psoriasis compared with AD. Our results support the use of dermoscopy as a useful tool to diagnose CTCL. HFUS could augment the dermatologic assessment, but further studies will be needed to define standardized parameters.

Improved evaluation of backscatter characteristics of soft tissue using high-frequency annular array

Clinical ultrasound is widely used for quantitative diagnosis. To clarify the relationship between anatomical and acoustic properties, high resolution imaging using high-frequency ultrasound (HFU) is required. However, when tissue properties are evaluated using HFU, the depth of field (DOF) is limited. To overcome this problem, an annular array transducer, which has a simple structure and produces high-quality images, is applied to HFU measurement. In previous phantom experiments, we demonstrated that the HFU annular array extends the DOF compared to that of a single-element transducer for quantitative ultrasound (QUS) analysis. Here, we extend that work by applying QUS methods to an ex vivo rat liver. The present study demonstrates that an annular array extends the region and improves the resolution for tissue characterization for an excised healthy rat liver. Amplitude envelope statistics and spectral-based analysis are used as QUS methods.

Abstract 4559: Tumor-derived Galectin-1 promotes tumor growth in an orthotopic C57Bl/6 NB mouse model

Abstract Question We recently introduced the carbohydrate-binding protein Galectin-1 (Gal-1) as a novel tolerogeneic molecule in neuroblastoma (NB). NB-secreted Gal-1 suppressed the maturation of dendritic cells (DC) and inhibited T cell function. Here, we focused on the question whether tumor-derived Gal-1 is the decisive factor to promote tumor growth in our model for NB. Methods C57Bl/6J-derived orthotopic growing NB cells (named NB975A) were used for all culture as well in vivo experiments. Gal-1 knock-down clones (GL) were generated by stable transfection of wt NB975A cells (NBA) with the antisense Gal-1 expression vector (NBA-GL), (kindly provided by Dr. Rabinovich). Blasticidine resistant (5 mikrogram/ml) transfectants were cloned by limited dilution. Protein expression of Gal-1 was determined by Western blot. Orthotopic NB tumors were generated in C57Bl/6J wild type and Gal-1-knock-out (Lgals-/-) female mice by subcapsular tumor cell injection of NBA-GL or wild type NBA (1x106, 0,1 ml PBS) into the left kidney. Primary tumor growth was analyzed by using high frequency ultrasound measurement. Mice were sacrificed 23 days after tumor inoculation and tumor tissue was harvested for further analysis. Results NBA-GL showed 50% reduced protein expression of Gal-1 compared to control wild type NBA cells. In vitro viability and proliferation of the tumor cells was not affected by the transfection. Mice inoculated with NBA-GL cells had significantly smaller primary tumors when compared with control animals that received the NBA cells. Gal-1 sufficient tumor cells injected in Gal-1-deficient host mice grew normally. Conclusion Tumor-derived Gal-1 and not its expression in host is critical for the promotion of tumor growth. Citation Format: Stefan Fest. Tumor-derived Galectin-1 promotes tumor growth in an orthotopic C57Bl/6 NB mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4559.

Abstract 4570: Selective depletion of regulatory T cells suppressed neuroblastoma tumor growth in mice

Abstract Purpose of the study Neuroblastoma (NB) is the most common solid extracranial tumor in childhood. Regulatory T cells (Treg) are known to have immune suppressive capacity and to be involved in tolerance establishment. As they support tumor growth and help some tumors to overcome recognition by the host, they are considered to be an important target. Treg are reportedly increased in blood of NB patients. However, there are no scientific proofs to date that they are involved in neuroblastoma growth. To address this important question we employed Foxp3-DTR mice to selectively deplete Treg upon orthotopic application of syngeneic neuroblastoma cells. Methods Orthotopic NB tumors were generated in mice Foxp3-DTR mice and in C57Bl/6J controls by subcapsular tumor cell injection of NB975A cells into the left kidney. Primary tumor growth was analysed for 23 days by high frequency ultrasound measurement. To deplete Treg, InjectionDepletion of Diphtheria Toxin (DT, 15 ng/g bodyweight) intraperitoneally every 4 days in Foxp3.DTR mice depleted the Treg pool. Control Foxp3.DTR animals received PBS and control C57B/l6 received DT. All mice were sacrificed 23 days after tumor inoculation. Tumor as wells as immune cells harvested from spleen and inguinal lymph nodes were analyzed by Flow Cytometry, Immunofluorescenceimmunohistochemistry and qRT-PCR. Results In control mice bearing tumors, Treg presence was confirmed at the contact zone between the kidney and the growing, inoculated tumor. Mice devoid of Treg (Foxp3-DTR+DT) showed a significantly reduced tumor growth compared to animals with normal Treg frequencies (Foxp3-DTR+PBS). Tumor growth in wild type controls was not affected by the application of DTR. Conclusion Ablation of Treg hindered the growth of NB, strongly suggesting their potential as therapeutic target for this aggressive childhood tumor. Citation Format: Sophie von Lenthe, Christine Weißenborn, Ana Claudia Zenclussen, Stefan Fest, Leonid Metelitsa. Selective depletion of regulatory T cells suppressed neuroblastoma tumor growth in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4570.

Influence of Microstructure on the High-Frequency Ultrasound Measurement of Peak Density

Peak density is an ultrasound measurement, which has been found to vary according to microstructure, and is defined as the number of local extrema within the resulting power spectrum of an ultrasound measurement. However, the physical factors which influence peak density are not fully understood. This work studies the microstructural characteristics which affect peak density through experimental, computationa,l and analytical means for high-frequency ultrasound of 22–41 MHz. Experiments are conducted using gelatin-based phantoms with glass microsphere scatterers with diameters of 5, 9, 34, and 69 μm and number densities of 1, 25, 50, 75, and 100 mm−3. The experiments show the peak density to vary according to the configuration. For example, for phantoms with a number density of 50 mm−3, the peak density has values of 3, 5, 9, and 12 for each sphere diameter. Finite element simulations are developed and analytical methods are discussed to investigate the underlying physics. Simulated results showed similar trends in the response to microstructure as the experiment. When comparing scattering cross section, peak density was found to vary similarly, implying a correlation between the total scattering and the peak density. Peak density and total scattering increased predominately with increased particle size but increased with scatterer number as well. Simulations comparing glass and polystyrene scatterers showed dependence on the material properties. Twenty-four of the 56 test cases showed peak density to be statistically different between the materials. These values behaved analogously to the scattering cross section.

Registration of human skull computed tomography data to an ultrasound treatment space using a sparse high frequency ultrasound hemispherical array.

Transcranial focused ultrasound (FUS) shows great promise for a range of therapeutic applications in the brain. Current clinical investigations rely on the use of magnetic resonance imaging (MRI) to monitor treatments and for the registration of preoperative computed tomography (CT)-data to the MR images at the time of treatment to correct the sound aberrations caused by the skull. For some applications, MRI is not an appropriate choice for therapy monitoring and its cost may limit the accessibility of these treatments. An alternative approach, using high frequency ultrasound measurements to localize the skull surface and register CT data to the ultrasound treatment space, for the purposes of skull-related phase aberration correction and treatment targeting, has been developed. A prototype high frequency, hemispherical sparse array was fabricated. Pulse-echo measurements of the surface of five ex vivo human skulls were made, and the CT datasets of each skull were obtained. The acoustic data were used to rigidly register the CT-derived skull surface to the treatment space. The ultrasound-based registrations of the CT datasets were compared to the gold-standard landmark-based registrations. The results show on an average sub-millimeter (0.9 ± 0.2 mm) displacement and subdegree (0.8° ± 0.4°) rotation registration errors. Numerical simulations predict that registration errors on this scale will result in a mean targeting error of 1.0 ± 0.2 mm and reduction in focal pressure of 1.0% ± 0.6% when targeting a midbrain structure (e.g., hippocampus) using a commercially available low-frequency brain prototype device (InSightec, 230 kHz brain system). If combined with ultrasound-based treatment monitoring techniques, this registration method could allow for the development of a low-cost transcranial FUS treatment platform to make this technology more widely available.

High-Frequency Ultrasound as an Option for Scanning of Prepared Teeth: An in Vitro Study

Because of its ability to non-invasively capture hard structures behind soft tissue, high-frequency ultrasound (HFUS)-assisted microscanning could be a patient-friendly and promising alternative for digitization of prepared teeth. However, intra-oral HFUS microscanners for taking digital impressions of prepared teeth are still not available in the clinical setting. Because working range, scanner size, scanning time, surface reconstruction accuracy and costs are major factors in such a system, our overall objective is to minimize hardware efforts and costs while maintaining the accuracy of the surface-reconstructed tooth model in the range 50 μm. In the work described here, we investigated the accuracy of tooth impression taking using a single-element HFUS microscanner with only three translational degrees of freedom under the restriction that only one occlusal scan is performed per tooth. As in favor of time and scanning efforts the data density is expected to be low, the surface reconstruction process is linked to a model-based surface reconstruction approach using a thin spline robust point matching algorithm to fill data gaps. A priori knowledge for the model is generated based on the original HFUS measurement data. Three artificial teeth and one human molar were prepared and scanned using an extra-oral HFUS laboratory microscanner that was built to test and evaluate different scanning setups. A scanner with three translational degrees of freedom was used to scan the teeth from an occlusal direction. After application of the proposed thin-spline robust point matching algorithm-based reconstruction approach, reconstruction accuracy was assessed by comparing the casts with a control group scanned with an extra-oral laser-scanning system. The mean difference between the reconstructed casts and the optical control group was in the range 14–53 μm. The standard deviation was between 21 and 52 μm. This let us assume that the suggested approach can help to decrease hardware efforts while maintaining the robustness of the 3-D surface reconstruction process for future HFUS-based intra-oral scanners.

High frequency ultrasound measurements on a translucent thin bioglass, based on Si, Ca, Na: Study of the distribution of elastic modulus

In this work, an ultrasonic high frequency focused sensor (100MHz) has been used to study the variation of the elastic modulus of a thin bioglass element, based on Si, Ca, Na. In fact, physical functionalization of materials may play a role in defining the properties of interfaces of the surface depending of the physico-chemical characteristics of the materials used. The study is restricted to the characterization by an ultrasonic method of the elastic modulus profile of the bioglass element during the final phase of processing: before and after thermal treatment. The initial objective is to produce an ultrasonic map of the element under investigation, such as a substrate, prior to further tests involving adhesion of biological cells in order to try to understand the relationship between the distribution of the measured mechanical properties and the adhesion phenomenon.

2P5-2 High Frequency Ultrasound Measurement of Micro Displacement in Human Skin Induced by Arterial Pulsation(Poster Session)

2P5-2 High Frequency Ultrasound Measurement of Micro Displacement in Human Skin Induced by Arterial Pulsation(Poster Session)

High-Frequency Ultrasound Measurements of the Normal Ciliary Body and Iris

To determine the normal ultrasonographic thickness of the iris and ciliary body. This prospective 35-MHz ultrasonographic study included 80 normal eyes of 40 healthy volunteers. The images were obtained at the 12-, 3-, 6-, and 9-o'clock radial meridians, measured at three locations along the radial length of the iris and at the thickest section of the ciliary body. Mixed model was used to estimate eye site-adjusted means and standard errors and to test the statistical difference of adjusted results. Parameters included mean thickness, standard deviation, and range. Mean thicknesses at the iris root, midway along the radial length of the iris, and at the juxtapupillary margin were 0.4 ± 0.1, 0.5 ± 0.1, and 0.6 ± 0.1 mm, respectively. Those of the ciliary body, ciliary processes, and ciliary body + ciliary processes were 0.7 ± 0.1, 0.6 ± 0.1, and 1.3 ± 0.2 mm, respectively. This study provides standard, normative thickness data for the iris and ciliary body in healthy adults using ultrasonographic imaging.

High-frequency ultrasound measurement for assessing post-thrombotic syndrome and monitoring compression therapy in chronic venous disease

High-frequency ultrasound measurement for assessing post-thrombotic syndrome and monitoring compression therapy in chronic venous disease

High frequency ultrasound measurement of digital dermal thickness in systemic sclerosis

BackgroundCurrently, assessment of dermal thickness in systemic sclerosis (SSc) is performed by palpation and assessment using the modified Rodnan skin score (mRSS).ObjectiveTo verify whether high frequency ultrasound (US) may be...

High-frequency ultrasound measurement for assessing post-thrombotic syndrome and monitoring compression therapy in chronic venous disease

The purpose of this study was to validate high-frequency ultrasound (HFU) measurement of dermal thickness for quantification of edema in patients with different severities of chronic venous disease. HFU measurements of dermal thickness were made with a 17-MHz probe (Philips iU22 Ultrasound scanner, Bothell, Wash) or a 20-MHz medium-focus probe (DermaScan-C, Cortex Technology, Denmark), 7.5 cm above the medial malleolus. For validation, 20 patients with venous leg ulcers who were not receiving compression therapy, 20 patients with previous deep vein thrombosis (DVT) and symptoms of post-thrombotic syndrome (PTS) without ulceration, and 31 age-matched healthy controls were measured on a single occasion. To investigate the effect of compression on dermal thickness, the leg ulcer patients from the validation study were treated with compression therapy for 7 weeks and measured after 1, 3, 5, and 7 weeks. The association between dermal thickness and the clinical (C) component of the CEAP classification was examined in a cross-sectional analysis of 157 patients with a confirmed history of DVT >or=3 years ago. Dermal thickness in patients with venous leg ulcers before compression therapy (median, 2.56 mm; interquartile range [IQR], 2.31-2.82 mm) was significantly greater (P = .002) than that in patients with symptoms of PTS without ulceration (median, 2.16 mm; IQR, 1.90-2.36 mm). Dermal thickness in both groups was significantly greater (P < .0001) than the control group (median, 1.34 mm; IQR, 1.29-1.44 mm). Compression therapy caused a steady and significant decrease in dermal thickness during the first 5 weeks until normal control levels were achieved. Dermal thickness increased with increasing CEAP category. In 121 patients with a positive diagnosis of DVT >or=3 years ago from Radiology Department records, a hypothetical test cutoff of 1.985 mm for the prediction of severe PTS noted as C(4b), C(5), and C(6) (lipodermatosclerosis or leg ulceration) had a positive predictive value of 46.9% and a negative predictive value of 90.3%. HFU measurement of dermal thickness enables the monitoring of edema reduction by compression therapy. A prospective study is required to determine the temporal dynamics of dermal thickness changes after DVT and the relationship to the development of PTS. This test has the potential to be beneficial in the follow-up of patients after a DVT and provide clinical evidence for using graduated elastic compression stockings to control edema and prevent the development of more advanced skin changes.

High-frequency ultrasound measurement of dermis and subcutaneous fat in the newborn infant.

Skin thickness and subcutaneous fat thickness of newborn infants may reflect the condition of the infant including prematurity. Skin thickness and subcutaneous fat thickness might be useful parameters to characterize and monitor the nutritional state of the infant. The objective was to introduce ultrasonography for this purpose. A high-frequency (20 MHz) ultrasound A-mode scanner was employed. Skinfold caliper recordings were performed for comparison. Frontal skin and skin of the back were studied in 7 infants with body weight 1095-4750 g (also studied with B-mode scanning). 46 infants weighing 925-4120 g were studied and correlated with skinfold recording. A high degree of correlation between skinfold recordings and ultrasound measurements (A-mode) of subcutaneous fat was found, coefficient of correlation 0.84, p<0.001. High-frequency ultrasound measurement of skin and subcutaneous fat thickness is precise and reliable for in vivo assessment of body fat in newborn infants. Further validation of the technique relative to neonatal skin and nutritional state is, however, needed before the ultrasound technique can be used as routine in neonatalogical monitoring.

High-Frequency Ultrasound Measurement of the Thickness of the Corneal Epithelium

385 From the Department of Ophthalmology and the Margaret M. Dyson Vision Research Institute, Cornell University Medical College, New York, NY. The authors have no proprietary interest in any materials or methods described within this article. Reprint requests should be addressed to D. Jackson Coleman, MD, The Margaret M. Dyson Vision Research Institute, Cornell University Medical College, 1300 York Ave, Room A-855, New York, NY 10021. Received: March 10, 1993 Accepted: July 7, 1993 High-Frequency Ultrasound Measurement of the Thickness of the Corneal Epithelium

High-frequency ultrasound measurement of patch test reactions.

53 patients who produced 34 positive patch test reactions (+/- 15, +10, ++4, +++5) had their reactions read by a high-frequency pulsed ultrasonic (A-scan) dermal depth detector with a resolution of 0.05 mm. The positive reactions were compared with both random and regional controls. The machine could not differentiate between + or +/- reactions from the control readings. However, for 75% of ++ cases and 80% of +++ cases, a significant change was confirmed by the detector. It is concluded that the high-frequency ultrasound method is of little use in confirming or quantifying of positive patch test results.