Ultrasonic mapping of midpalatal suture - An ex-vivo study

OBJECTIVE

Rapid maxillary expansion is a common orthodontic procedure to correct maxillary constriction. Assessing the midpalatal suture (MPS) expansion plays a crucial role in treatment planning to determine its effectiveness. The objectives of this preliminary investigation are to demonstrate a proof of concept that the palatal bone underlying the rugae can be clearly imaged by ultrasound (US) and the reconstructed axial view of the US image accurately maps the MPS patency.

METHODS

An ex-vivo US scanning was conducted on the upper jawbones of two piglet's carcasses before and after the creation of bone defects, which simulated the suture opening. The planar images were processed to enhance bone intensity distribution before being orderly stacked to fuse into a volume. Graph-cut segmentation was applied to delineate the palatal bone to generate a bone volume. The accuracy of the reconstructed bone volume and the suture opening was validated by the micro-computed tomography (µCT) data used as the ground truth and compared with cone beam computed tomography (CBCT) data as the clinical standard. Also included in the comparison is the rugae thickness. Correlation and Bland-Altman plots were used to test the agreement between the two methods: US versus µCT/CBCT.

RESULTS

The reconstruction of the US palatal bone volumes was accurate based on surface topography comparison with a mean error of 0.19 mm for pre-defect and 0.15 mm and 0.09 mm for post-defect models of the two samples, respectively when compared with µCT volumes. A strong correlation (R2 ≥ 0.99) in measuring MPS expansion was found between US and µCT/CBCT with MADs of less than 0.05 mm, 0.11 mm and 0.23 mm for US, µCT and CBCT, respectively.

CONCLUSIONS

It was possible to axially image the MPS opening and rugae thickness accurately using high-frequency ultrasound.

CLINICAL SIGNIFICANCE

This study introduces an ionizing radiation-free, low-cost, and portable technique to accurately image a difficult part of oral cavity anatomy. The advantages of conceivable visualization could promise a successful clinical examination of MPS to support the predictable treatment outcome of maxillary transverse deficiency.

Ultrasound features of high-risk basal cell carcinoma: a systematic review

Basal Cell Carcinoma (BCC) is the most prevalent skin cancer and continues to witness a surge in incidence rates. The categorization of BCC subtypes into low or high risk, guided by recurrence and invasiveness metrics, underscores the need for precise differentiation. While the punch biopsy remains the gold standard for diagnosis, its invasiveness prompts a need for non-invasive alternatives. Ultrasound (US) has emerged as a noteworthy candidate, gaining momentum in its potential to offer a less intrusive diagnostic approach. We conducted a systematic review regarding features of the high-risk subtypes of BCC on US. A thorough literature search of PubMed Medline, Embase, and CINAHL databases was conducted according to PRISMA guidelines and a total of nine studies meeting our inclusion criteria were included in this review. Evidence is still nascent but US features such as lesional shape, depth, hyperechoic spots, and color doppler may be helpful in differentiating high-risk BCC subtypes. However, further prospective studies with standardized interventions and outcome measures are required.

High-frequency ultrasonography for subungual glomus tumor evaluation - imaging findings

OBJECTIVE

This article aimed to describe the common imaging features of subungual glomus tumors.

METHODS

The study involved data collected between January 2019 and December 2022. Twenty-three patients with a total of 31 glomus tumors underwent high-frequency ultrasound examinations with a 24-MHz probe. Two experienced radiologists independently evaluated the images, and only data from the more experienced radiologist were used for subsequent analyses.

RESULTS

The average size of the tumors was 4.6 mm, and most of them appeared homogeneously hypoechogenic (90.3%). Bone remodeling of the distal phalanx was observed in 87.1% of cases, with an average axial circumference loss of 0.8 mm, indicating the slow and expansive growth of glomus tumors. Intense vascularization was found in 54.8% of cases on Doppler images, and the stalk sign, reflecting the vascular origin of the tumor, was present in 64.5% of cases. The most common clinical feature was pain, reported in 84.6% of cases, with a mean pain scale score of 7.0, indicating a negative impact on patients' lives despite being benign tumors.

CONCLUSION

The study concludes that ultrasound evaluation is highly useful for diagnosing glomus tumors, especially when multiple findings, such as bone remodeling, hypervascularization, and the stalk sign, are present. This method allows for accurate diagnosis, observation of periungual structures, and proper surgical planning, ultimately reducing recurrence rates.

Application of High-Frequency Ultrasound to Evaluate Forehead Filling Materials

BACKGROUND

In recent years, soft tissue materials have been applied as forehead fillers. Some filling materials need to be removed or refilled in a timely manner in certain situations; therefore, it is important to develop a method to identify the location and type of filling materials. This study summarizes the imaging findings of different filling materials under high-frequency ultrasound, providing a reference for clinical treatment.

METHODS

We screened facial ultrasound images performed at the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences from April 2015 to July 2023 and classified and summarized the types of frontal filling materials and their imaging results.

RESULTS

This study included ultrasound imaging results from 114 patients, including 39 with hyaluronic acid (HA) filling, 45 with polyacrylamide hydrogel (PAG) filling, 14 who received autologous fat transplantation, 2 who received prosthesis implantation, 2 who received both HA and PAG filling, and 12 who received silicone oil filling. HA mainly manifests as an anechoic zone on ultrasonography, with images divisible into four types. PAG primarily presents as fine punctate echoes, divisible into five types. Fat transplantation presents as a low-echo area with uneven density, divisible into five types. Finally, the silicone oil-filling material appears as a cloud-like high echo on the forehead, visible throughout the entire skin layer, and unclear imaging in deep tissues.

CONCLUSION

High-frequency ultrasound is a safe and reliable method to evaluate the type and position of forehead filling materials, which can be easily applied in clinical practice.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

High-frequency ultrasound imaging findings in the diagnosis of segmental schwannomatosis of the ulnar nerve: case report and literature review

Schwannomatosis is characterized by the development of multiple schwannomas without evidence of vestibular tumors. Segmental schwannomatosis is defined as being limited to one limb or five or fewer contiguous segments of the spine. We report a case of a 20-year-old male with the painful masses of the left upper extremity with associated numbness and paresthesia in the ulnar nerve distribution. The high-frequency ultrasound showed that the ulnar nerve fascicles were enlarged and expanded with beadlike growth. The patient underwent surgery twice and all the tumors were pathologically confirmed to be schwannomas. Together, the medical history, imaging, and pathology findings indicated the diagnosis of segmental schwannomatosis. By the imaging diagnostic tools, MRI is the most commonly used in assistance with diagnosis of segmental schwannomatosis while high-frequency ultrasonography is rare. In this paper, we discuss the value of high-frequency ultrasonography in the diagnosis of this rare disease. This case report provides a deeper understanding of segmental schwannomatosis and may help improve the accuracy of preoperative diagnosis.

The Ultrasound Evolution of Lateral Thoracic Perforator Flaps Design and Harvest for Partial and Total Breast Reconstruction

BACKGROUND

The lateral thoracic area is a known source for perforator flaps for partial breast reconstruction. In this paper, we report our experience in designing and harvesting lateral thoracic perforator flaps for partial and total breast reconstruction with the introduction of the "propuller" concept.

PATIENTS AND METHODS

Between September 2013 and August 2021, 95 flaps were performed for immediate, partial and total breast reconstruction. On a total of 95 flaps, 30 (19 thoracodorsal artery perforator(TDAP) flaps, 10 lateral intercostal artery perforator(LICAP) flaps and 1 lateral thoracic artery perforator(LTAP) flap) were harvested in the traditional fashion (control group) and 65 (57 LICAP, 2 LTAP and 6 TDAP flaps) according to the propeller concept (study group). All cases were preoperatively planned with Color-Coded Duplex Ultrasound.

RESULTS

No flap losses were experienced in both groups. The mean operative time was 156 minutes (range 118-234) for the control group and 75 minutes (range 53-125) for the study group (p < 0.0001). A significantly higher number of LICAP flaps were chosen in the study group compared to control group. None of the patients had donor site complications. Patients' and Surgeons' satisfaction was high to very high.

CONCLUSION

The ultrasound preoperative planning led to the development of an easier and safer method of local perforator flap harvesting, that we named as propuller design. Its novelty lies in that perforator intraoperative selection and fully skeletonization are not needed and a more efficient flap movement (propeller plus advancement) which transfers more tissue into the new breast can be achieved safely, faster and easier.

The use of a fluorine mass balance to demonstrate the mineralization of PFAS by high frequency and high power ultrasound

High-frequency ultrasound (sonolysis) has been shown as a practical approach for mineralizing PFAS in highly concentrated PFAS waste. However, a fluorine mass balance approach showing complete mineralization for ultrasound treatment has not been elucidated. The impact of ultrasonic power density (W/L) and the presence of co-occurring PFAS on the degradation of individual PFAS are not well understood. In this research, the performance of a 10L sonochemical reactor was assessed for treating synthetic high-concentration PFAS waste with carboxylic and sulfonic perfluoroalkyl surfactants ranging in chain length from four to eight carbons at three different initial concentrations: 6, 55, 183 μM. The mass balance for fluorine was performed using three analytical techniques: triple quadrupole liquid chromatography-mass spectrometry, a fluoride ion selective electrode, and 19F nuclear magnetic resonance. The test results showed near complete mineralization of PFAS in the waste without the formation of intermediate fluorinated by-products. The PFAS mineralization efficiency of the sonolysis treatment at two different power densities for similar initial concentrations were almost identical; the G value at 145 W/L was 9.7*10-3 g/kWh, whereas the G value at 90 W/L was 9.3*10-3 g/kWh. The results of this study highlight the implications for the scalability of the sonolytic process to treat high-concentration PFAS waste.

Diagnostic value of high-frequency ultrasound in omohyoid muscle syndrome

PURPOSE

To investigate the diagnostic value of high-frequency ultrasound in omohyoid muscle syndrome.

MATERIAL AND METHODS

A retrospective analysis of 11 patients diagnosed with omohyoid muscle syndrome was carried out, and the characteristics of high-frequency ultrasound images were summarized.

RESULTS

Ultrasonography of the omohyoid muscle showed a narrow band of hypoechoic muscle bundle. The ultrasonographic manifestation of omohyoid muscle syndrome showed a thickening of the omohyoid muscle on the affected side. The omohyoid muscle on the affected side bulged forward during swallowing and lifted the overlying sternocleidomastoid muscle. The difference between the thickness of the omohyoid muscle intermediate tendon on the affected side and the healthy side at rest was statistically significant (t = 58.23, P < 0.001). The difference between the thickness of the affected omohyoid muscle intermediate tendon at rest and during swallowing was statistically significant (t = 14.57, P < 0.001). There was no statistically significant difference between the thickness of the omohyoid muscle intermediate tendon on the healthy side at rest and during swallowing (t = 0.56, P > 0.05).

CONCLUSION

High-frequency ultrasound is the preferred imaging method in the diagnosis of omohyoid muscle syndrome.

Imaging features for the evaluation of skin and nail infections

Clinical manifestations of dermatological and musculoskeletal conditions can sometimes overlap, leading to confusion in diagnosis. Patients with nail and skin infections may undergo imaging examinations with suspicions of muscle, tendon, or joint injuries. Dermatological infections often involve soft tissues and musculoskeletal structures, and their etiology can range from fungi, bacteria, viruses, to protozoa. Relying solely on physical examination may not be sufficient for accurate diagnosis and treatment planning, necessitating the use of complementary imaging exams. The objective of this paper is to present and discuss imaging findings of the main infectious conditions affecting the nail apparatus and skin. The paper also highlights the importance of imaging in clarifying diagnostic uncertainties and guiding appropriate treatment for dermatological conditions.

Diagnostic Efficacy of High-frequency Ultrasound (HFU) in Early Diagnosis of Congenital Hip Dysplasia

BACKGROUND

Hip dysplasia is one of the most prevalent disorders in children and one of the three primary congenital orthopedic deformities. Although there are numerous existing methods (e.g., CT, MRI and arthrography) for early identification of hip dysplasia, their diagnostic criteria differ widely. It is critical to establish a safe, accurate, and reliable way for early diagnosis and treatment of hip dysplasia.

OBJECTIVE

This study aimed to analyze the diagnostic efficacy of high-frequency ultrasound (HFU) for congenital developmental hip dysplasia and hip dislocation and to provide a reference for the early diagnosis of congenital hip dysplasia in the future.

METHODS

A total of 104 infants and children suspected of having congenital hip dislocation or developmental hip dysplasia admitted to our hospital from April 2019 to August 2022 were enrolled as study subjects. All the infants and children were subjected to HFU and X-ray examination in our hospital. The diagnostic efficacy of HFU for congenital hip dysplasia was observed using X-ray as the gold standard.

RESULTS

HFU confirmed 79 cases of congenital hip dysplasia, while X-ray confirmed 71 cases. The sensitivity and specificity of HFU were 77.42% and 83.33%, respectively, in the diagnosis of congenital developmental hip dysplasia, 76.47% and 96.55% in the diagnosis of congenital hip dislocation, and 77.22% and 60% in the diagnosis of congenital hip abnormality, which is very close to the gold standard. According to statistics on infants and children, the majority of patients were girls, and the left joint was more likely to be affected.

CONCLUSION

HFU has excellent diagnostic efficiency for congenital developmental hip dysplasia and hip dislocation, which can be considered an early assessment method for congenital hip dysplasia in the future.

Superficial Bifurcated Microflow Phantom for High-Frequency Ultrasound Applications

OBJECTIVE

To evaluate and optimize high-frequency ultrasound (HFUS) imaging techniques that visualize the morphology of microscale vasculatures, many studies have used flow phantoms with straight channels. However, the previous phantoms lack the complexity of microvessels to simulate a realistic vascular environment in a shallow depth. This study was aimed at devising a new protocol for fabrication of a microflow phantom with bifurcated geometry at a superficial region.

METHODS

The proposed protocol involved the following features: (i) a bifurcated flow tract model 300 µm in diameter was debossed on the surface of a tissue slab made of polyvinyl alcohol cryogel, and (ii) a wall-less lumen was created via bonding tissue slabs to put a lid on the debossed flow tract. The structure of the created microflow phantom was evaluated using 2-D and 3-D power Doppler imaging with a 30 MHz HFUS modality.

RESULTS

Ultrasound imaging revealed that the desired flow tract with bifurcation was successfully created in the phantom at a depth of 2-5 mm from the ultrasound probe. The diameters of the flow tract measured in the axial direction were 307 ± 3.7 µm in the parent branch and 232 ± 18.2 and 256 ± 23.3 µm in the two daughter branches, respectively.

CONCLUSION

The experiments revealed that the proposed protocol for creating a microscale intricate flow tract with desired dimensions and depth is valid. This new phantom will facilitate further improvement in the ultrasound technologies for the precise visualization of superficial complex vasculatures such as those in skin layers.

Screening for early rheumatoid arthritis using high-frequency ultrasound, serum RANKL, and OPG detection

OBJECTIVE

To conduct a comparative study of high-frequency ultrasound and magnetic resonance imaging (MRI) combined with serum RANKL and OPG detection, and assess the efficacy of high-frequency ultrasound with RANKL and OPG detection in screening early rheumatoid arthritis (RA).

METHOD

High-frequency ultrasound and MRI were performed on both carpal joints of 60 patients with early RA, and the frequencies of synovitis, joint effusion, tenosynovitis, and bone erosion detected by high-frequency ultrasound and MRI were observed. The serum levels of receptor activator for nuclear factor-κB ligand (RANKL) and osteoclastogenesis inhibitory factor (OPG) were also detected. The serum levels of RANKL and OPG were also detected in 80 normal healthy examinees. The data were recorded and statistically analyzed.

RESULTS

The detection rates of carpal synovitis, joint effusion, tenosynovitis, and bone erosion in RA patients by high-frequency ultrasound were 81.66%, 69.16%, 63.33%, and 1.66%, respectively, while the detection rates by MRI were 80.00%, 71.66%, 65.00%, and 15.00%, respectively. There was no significant difference between high-frequency ultrasound and MRI in the detection rates of carpal synovitis, joint effusion, and tenosynovitis in RA patients (P > 0.05), while the detection rate of bone erosion by high-frequency ultrasound was significantly lower than that by MRI. The serum levels of RANKL and OPG in RA patients were 231.47 and 68.71, respectively, while the serum levels of RANKL and OPG in normal healthy examinees were 123.51 and 385.05, respectively. The serum RANKL levels of RA patients were significantly higher than those of healthy examinees, while the serum OPG levels of RA patients were significantly lower than those of healthy examinees, which were statistically significant (P < 0.01). The AUC values of the ROC curves obtained by high-frequency ultrasound and MRI combined with serum RANKL and OPG detection in Synovitis modeling were 0.955 and 0.954, respectively. The AUC values of the ROC curves obtained from the joint fusion modeling using high-frequency ultrasound and MRI combined with serum RANKL and OPG detection were 0.949 and 0.950, respectively. The AUC values of the ROC curves obtained from modeling Tenosynovitis using high-frequency ultrasound and MRI combined with serum RANKL and OPG detection were 0.941 and 0.949, respectively. The AUC values of ROC curves obtained by combining high-frequency ultrasound and MRI with serum RANKL and OPG detection in Bone erosion modeling were 0.908 and 0.923, respectively.

CONCLUSION

High-frequency ultrasound combined with serum RANKL and OPG detection has comparable effects to MRI on screening early RA, providing a safe, simple, and cost-effective screening method for the early detection of RA patients. Key Points • High-frequency ultrasound and MRI can effectively detect early lesions of the wrist joints in RA patients. • Ultrasound diagnosis has the advantages of being quick, inexpensive, and repeatable, making it the preferred choice of imaging examination for RA patients at an early stage.

Diagnosis of diabetes mellitus using high frequency ultrasound and convolutional neural network

The incidence of diabetes mellitus has been increasing, prompting the search for non-invasive diagnostic methods. Although current methods exist, these have certain limitations, such as low reliability and accuracy, difficulty in individual patient adjustment, and discomfort during use. This paper presents a novel approach for diagnosing diabetes using high-frequency ultrasound (HFU) and a convolutional neural network (CNN). This method is based on the observation that glucose in red blood cells (RBCs) forms glycated hemoglobin (HbA1c) and accumulates on its surface. The study incubated RBCs with different glucose concentrations, collected acoustic reflection signals from them using a custom-designed 90-MHz transducer, and analyzed the signals using a CNN. The CNN was applied to the frequency spectra and spectrograms of the signal to identify correlations between changes in RBC properties owing to glucose concentration and signal features. The results confirmed the efficacy of the CNN-based approach with a classification accuracy of 0.98. This non-invasive diagnostic technology using HFU and CNN holds promise for in vivo diagnosis without the need for blood collection.

Ultrasound imaging of onychopapilloma: Evaluation of 43 cases

INTRODUCTION

Onychopapilloma is a benign tumor presenting as an isolated benign warty distal matrix and bed lesion in association with longitudinal erythronychia for which no underlying cause can be identified. Diagnosis might be challenging due to other, more severe, causes of erythronychia.

OBJECTIVES

This study aimed to investigate the clinical and sonographic features of onychopapilloma using high-frequency ultrasound.

METHODS

Between February 2022 and May 2023, a cross-sectional study was conducted, involving 39 patients displaying clinical features suggestive of onychopapilloma. These patients were selected at random and underwent examination using high-frequency ultrasound. High-frequency ultrasound assessments of the nail unit were carried out using 33 MHz and 24 MHz high-frequency linear transducers. An experienced radiologist performed the ultrasound scans while participants assumed an orthostatic seated position. Subsequently, the collected ultrasound images were independently evaluated by two radiologists specializing in nail injuries, ensuring a blinded assessment. This evaluation aimed to provide comprehensive insights into the imaging characteristics of onychopapilloma.

RESULTS

High-frequency ultrasound revealed oval or linear hyperechoic masses located in the middle of the nail plate, without vascularity or posterior acoustic shadowing. Nail plate irregularity, thickening, and nail bed indentation were observed in some cases. These findings demonstrate that high-frequency ultrasound can aid in the diagnosis and surgical planning of onychopapilloma, providing detailed visualization of the lesion and surrounding structures.

CONCLUSIONS

This imaging method could represent a potential tool to differentiate onychopapilloma from other nail conditions, especially malignant neoplasms. However, further research is needed to validate these findings and assess long-term outcomes.

A deep learning fusion network trained with clinical and high-frequency ultrasound images in the multi-classification of skin diseases in comparison with dermatologists: a prospective and multicenter study

Background

Clinical appearance and high-frequency ultrasound (HFUS) are indispensable for diagnosing skin diseases by providing internal and external information. However, their complex combination brings challenges for primary care physicians and dermatologists. Thus, we developed a deep multimodal fusion network (DMFN) model combining analysis of clinical close-up and HFUS images for binary and multiclass classification in skin diseases.

Methods

Between Jan 10, 2017, and Dec 31, 2020, the DMFN model was trained and validated using 1269 close-ups and 11,852 HFUS images from 1351 skin lesions. The monomodal convolutional neural network (CNN) model was trained and validated with the same close-up images for comparison. Subsequently, we did a prospective and multicenter study in China. Both CNN models were tested prospectively on 422 cases from 4 hospitals and compared with the results from human raters (general practitioners, general dermatologists, and dermatologists specialized in HFUS). The performance of binary classification (benign vs. malignant) and multiclass classification (the specific diagnoses of 17 types of skin diseases) measured by the area under the receiver operating characteristic curve (AUC) were evaluated. This study is registered with www.chictr.org.cn (ChiCTR2300074765).

Findings

The performance of the DMFN model (AUC, 0.876) was superior to that of the monomodal CNN model (AUC, 0.697) in the binary classification (P = 0.0063), which was also better than that of the general practitioner (AUC, 0.651, P = 0.0025) and general dermatologists (AUC, 0.838; P = 0.0038). By integrating close-up and HFUS images, the DMFN model attained an almost identical performance in comparison to dermatologists (AUC, 0.876 vs. AUC, 0.891; P = 0.0080). For the multiclass classification, the DMFN model (AUC, 0.707) exhibited superior prediction performance compared with general dermatologists (AUC, 0.514; P = 0.0043) and dermatologists specialized in HFUS (AUC, 0.640; P = 0.0083), respectively. Compared to dermatologists specialized in HFUS, the DMFN model showed better or comparable performance in diagnosing 9 of the 17 skin diseases.

Interpretation

The DMFN model combining analysis of clinical close-up and HFUS images exhibited satisfactory performance in the binary and multiclass classification compared with the dermatologists. It may be a valuable tool for general dermatologists and primary care providers.

Funding

This work was supported in part by the National Natural Science Foundation of China and the Clinical research project of Shanghai Skin Disease Hospital.

In Vivo Adaptive Bayesian Regularized Lagrangian Carotid Strain Imaging for Murine Carotid Arteries and Its Associations With Histological Findings

OBJECTIVES

Non-invasive methods for monitoring arterial health and identifying early injury to optimize treatment for patients are desirable. The objective of this study was to demonstrate the use of an adaptive Bayesian regularized Lagrangian carotid strain imaging (ABR-LCSI) algorithm for monitoring of atherogenesis in a murine model and examine associations between the ultrasound strain measures and histology.

METHODS

Ultrasound radiofrequency (RF) data were acquired from both the right and left common carotid artery (CCA) of 10 (5 male and 5 female) ApoE tm1Unc/J mice at 6, 16 and 24 wk. Lagrangian accumulated axial, lateral and shear strain images and three strain indices-maximum accumulated strain index (MASI), peak mean strain of full region of interest (ROI) index (PMSRI) and strain at peak axial displacement index (SPADI)-were estimated using the ABR-LCSI algorithm. Mice were euthanized (n = 2 at 6 and 16 wk, n = 6 at 24 wk) for histology examination.

RESULTS

Sex-specific differences in strain indices of mice at 6, 16 and 24 wk were observed. For male mice, axial PMSRI and SPADI changed significantly from 6 to 24 wk (mean axial PMSRI at 6 wk = 14.10 ± 5.33% and that at 24 wk = -3.03 ± 5.61%, p < 0.001). For female mice, lateral MASI increased significantly from 6 to 24 wk (mean lateral MASI at 6 wk = 10.26 ± 3.13% and that at 24 wk = 16.42 ± 7.15%, p = 0.048). Both cohorts exhibited strong associations with ex vivo histological findings (male mice: correlation between number of elastin fibers and axial PMSRI: rs = 0.83, p = 0.01; female mice: correlation between shear MASI and plaque score: rs = 0.77, p = 0.009).

CONCLUSION

The results indicate that ABR-LCSI can be used to measure arterial wall strain in a murine model and that changes in strain are associated with changes in arterial wall structure and plaque formation.

High-frequency quantitative ultrasound for the assessment of the acoustic properties of engineered tissues in vitro

Acoustic properties of biomaterials and engineered tissues reflect their structure and cellularity. High-frequency ultrasound (US) can non-invasively characterize and monitor these properties with sub-millimetre resolution. We present an approach to estimate the speed of sound, acoustic impedance, and acoustic attenuation of cell-laden hydrogels that accounts for frequency-dependent effects of attenuation in coupling media, hydrogel thickness, and interfacial transmission/reflection coefficients of US waves, all of which can bias attenuation estimates. Cell-seeded fibrin hydrogel disks were raster-scanned using a 40 MHz US transducer. Thickness, speed of sound, acoustic impedance, and acoustic attenuation coefficients were determined from the difference in the time-of-flight and ratios of the magnitudes of US signals, interfacial transmission/reflection coefficients, and acoustic properties of the coupling media. With this approach, hydrogel thickness was accurately measured by US, with agreement to confocal microscopy (r² = 0.97). Accurate thickness measurement enabled acoustic property measurements that were independent of hydrogel thickness, despite up to 60% reduction in thickness due to cell-mediated contraction. Notably, acoustic attenuation coefficients increased with increasing cell concentration (p < 0.001), reflecting hydrogel cellularity independent of contracted hydrogel thickness. This approach enables accurate measurement of the intrinsic acoustic properties of biomaterials and engineered tissues to provide new insights into their structure and cellularity. STATEMENT OF SIGNIFICANCE: High-frequency ultrasound can measure the acoustic properties of engineered tissues non-invasively and non-destructively with µm-scale resolution. Acoustic properties, including acoustic attenuation, are related to intrinsic material properties, such as scatterer density. We developed an analytical approach to estimate the acoustic properties of cell-laden hydrogels that accounts for the frequency-dependent effects of attenuation in coupling media, the reflection/transmission of ultrasound waves at the coupling interfaces, and the dependency of measurements on hydrogel thickness. Despite up to 60% reduction in hydrogel thickness due to cell-mediated contraction, our approach enabled measurements of acoustic properties that were substantially independent of thickness. Acoustic attenuation increased significantly with increasing cell concentration (p < 0.001), demonstrating the ability of acoustic attenuation to reflect intrinsic physical properties of engineered tissues.

High-frequency ultrasound assessment of vulvar lichen sclerosus treated with photodynamic therapy

BACKGROUND

Patients with vulvar lichen sclerosus (VLS) are faced with a decreased quality of life and an increased risk of vulvar malignancy. 5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) can serve as an alternative for refractory VLS patients. However, high-frequency ultrasound (HFUS) has never been introduced in the ALA-PDT outcome assessment for VLS patients.

METHODS

A prospective study was conducted. Refractory VLS patients received two treatment courses of ALA-PDT (3 times of remedies at 2-week intervals for each course), and underwent clinical, HFUS and histopathological assessment. Statistical analysis comparing parameters at baseline and after ALA-PDT was performed.

RESULTS

Thirty-one VLS patients were included. Both subjective symptoms (itch and burning pain) and objective severity (lesion size and hypopigmentation) were relieved significantly after ALA-PDT treatment. Hypoechoic dermal band (HDB) thickness revealed by HFUS decreased progressively with successive ALA-PDT treatment, and the reduction value had a positive correlation with the reduction of inflammatory infiltration depth in histopathology. Collagen homogenization depth decrease was also noticed. Besides, adverse effects were recorded, mainly as mild and transient post-treatment edema and pain.

CONCLUSIONS

ALA-PDT is an effective and safe therapeutic option for refractory VLS patients. HFUS can act as a complement to the non-invasive treatment monitoring for its objectivity, quantifiability and precision in the distinct vertical perspective.

Diagnostic efficacy of high-frequency ultrasound and X-ray contrast enema in colonic strictures after necrotizing enterocolitis: a retrospective study

OBJECTIVE

To compare the efficacy of high-frequency ultrasound and X-ray contrast enema in the diagnosis of colonic strictures after necrotizing enterocolitis.

METHODS

This study included pediatric patients who developed progressive abdominal distension or constipation after conservative treatment for necrotizing enterocolitis at our hospital between June 2012 and April 2020. All patients had high-frequency ultrasounds and X-ray contrast enema, and we used surgery, pathology, and telephone return visits as the reference standard. Patients with colonic strictures were confirmed by surgery and pathology. A patient was considered without colonic stricture if no stricture was reported or did not have related symptoms during telephone return visits. The areas under the Receiver operating characteristic (ROC) curves were used as evaluation indexes to compare the differential efficacy of high-frequency ultrasound and X-ray contrast enema.

RESULTS

A total of 81 patients have been included in this study. Among them, 49 patients were diagnosed with colonic strictures after necrotizing enterocolitis. The AUCs for high-frequency ultrasound and X-ray contrast enema were 0.990 vs 0.938, respectively (p > 0.05).

CONCLUSION

The diagnostic efficacy of high-frequency ultrasound was similar to that of X-ray contrast enema, furthermore this study also demonstrates the benefits of using high-frequency ultrasound to identify colonic strictures after necrotizing enterocolitis.

High-Frequency Ultrasound Imaging Findings of Different Mental Injectable Soft Tissue Fillers

BACKGROUND

In recent years, the use of mental injectable soft tissue fillers is popular. However, some fillers are difficult to distinguish from pathological tissue, and some non-absorbable fillers need to be removed in time. Therefore, identification of different fillers is important. In this study, we summarized the ultrasonic manifestations of different mental injectable soft tissue fillers to provide references for clinical practice.

METHODS

We screened the mental ultrasound images from November 2014 to November 2021 in the Plastic Surgery Hospital of Chinese Academy of Medical Sciences, identified different filling injection materials, and summarized and classified the ultrasonic characteristics of each filling material.

RESULTS

A total of 244 cases were included, involving 62 cases of hyaluronic acid, 126 cases of polyacrylamide hydrogel, 19 cases of growth factor, 16 cases of calcium hydroxyapatite, 15 cases of silicone oil and 6 cases of fat. The ultrasonic manifestation of hyaluronic acid was anechoic area, which could be divided into six types according to the distribution characteristics. The ultrasonography of polyacrylamide hydrogel showed fine punctate echo, which could be divided into nine types. The ultrasonographic appearance of growth factor was similar to the echo of the surrounding tissue, and the boundary was not clear. Calcium hydroxyapatite was characterized by uneven hyperechoic area, which was spread in the tissue space, with unclear boundary with surrounding tissues. Sonographic patterns of silicone oil were hyperechoic and cloudy on high-frequency ultrasound. The deep tissue and periosteum layer were not clear. Transplanted fat showed isoechoic area or uneven low-echo area, with clear boundary and peripheral adipose tissue acoustic enhancement.

CONCLUSIONS

High-frequency ultrasound is safe and reliable for identification and typing of chin filling injection materials, which can be applied in clinical practice.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Rare malignant melanotic nerve sheath tumors of the upper limb nerves: utility of high-frequency ultrasonography in preoperative imaging

Melanotic nerve sheath tumor (MNST) is a rare variant of schwannoma. Here, we report an unusual case of multiple MNST lesions located in the upper limb nerves. The patient presented with a mass on the left wrist in 2016 and another mass on the left thumb in 2017. In both instances, magnetic resonance imaging scans confirmed multiple giant-cell tumors of the tendon sheath. Persistent pain in the left upper limb and numbness in the ring finger and little finger recurred in 2021. High-frequency ultrasound (HFUS) showed that the left brachial plexus nerves (C5-8) were widened compared with those on the contralateral side; the neuroma formed at the lateral cord, and the median nerve was markedly thickened. The surgical findings were consistent with the ultrasound results. Pathology confirmed that the tumors were malignant MNSTs. HFUS is important for preoperative diagnosis and lesion localization, even identifying some lesions that are unrecognized on magnetic resonance imaging; thus, HFUS is crucial for improving surgical strategy and decision-making.

Management of cutaneous melanoma: radiologists challenging and risk assessment

Melanoma patient remains a challenging for the radiologist, due to the difficulty related to the management of a patient more often in an advanced stage of the disease. It is necessary to determine a stratification of risk, optimizing the means, with diagnostic tools that should be optimized in relation to the type of patient, and improving knowledge. Staging and risk assessment procedures are determined by disease presentation at diagnosis. Melanoma staging is a critical tool to assist clinical decision-making and prognostic assessment. It is used for clinical trial design, eligibility, stratification, and analysis. The current standard for regional lymph nodes staging is represented by the sentinel lymph node excision biopsy procedure. For staging of distant metastases, PET-CT has the highest sensitivity and diagnostic odds ratio. Similar trend is observed during melanoma surveillance. The advent of immunotherapy, which has improved patient outcome, however, has determined new issues for radiologists, partly due to atypical response patterns, partly due to adverse reactions that must be identified as soon as possible for the correct management of the patient. The main objectives of the new ir-criteria are to standardize the assessment between different trials. However, these ir-criteria do not take into account all cases of atypical response patterns, as hyperprogression or dissociated responses. None of these criteria has actually been uniformly adopted in routine. The immune-related adverse events (irAEs) can involve various organs from head to toe. It is crucial for radiologists to know the imaging appearances of this condition, to exclude recurrent or progressive disease and for pneumonitis, since it could be potentially life-threatening toxicity, resulting in pneumonitis-related deaths in early phase trials, to allow a proper patient management.

[Conventional ultrasound diagnostics in dermatology]

The imaging of changes to the skin, the subcutis and especially the regional lymph nodes by high-resolution ultrasound is an integral part of routine dermatological diagnostics. This is mainly done with electronic scanners operating at frequencies between 7.5 and 20 MHz (conventional ultrasound diagnostics). In addition, there are very high-frequency ultrasound systems (frequencies up to 100 MHz) that are used for special scientific questions. Ultrasound diagnostics has a number of advantages over other cross-sectional imaging techniques but is more dependent than these on the individual experience of the examiner. Structured training and continuing education are therefore essential for ultrasound diagnostics, also in dermatology. The following overview describes the most important indications for conventional sonography in dermatology in addition to the physical, technical and administrative principles.

A high frequency endoscopic ultrasound imaging method combining chirp coded excitation and compressed sensing

Insufficient imaging penetration and large data acquisition are two of the major challenges of high-frequency ultrasound imaging. Based on the good autocorrelation properties of chirp signal and the feasibility of using compressed sensing theory to reconstruct high-quality ultrasound images with low sampling requirements, this paper proposed a chirp coded excitation combined with compressed sensing (CCE-CS) technique for high-frequency endoscopic ultrasound (HFEUS) imaging. The feasibility of the method was verified by a brief theoretical analysis, and the relevant parameters were selected and analyzed according to the actual engineering situation. Simulated phantoms and in-vitro tissue experiments were used to evaluate the performance of the CCE-CS. Simulation results demonstrate that CCE-CS is capable of reducing the impact of reconstruction errors and improving imaging quality through comparison with conventional methods. The reduction of reconstruction data had less impact on penetration depth, resolution and general contrast general contrast-to-noise ratio (gCNR), and the reconstructed image was closer to the original image with a maximum improvement of 37% in peak signal-to-noise ratio (PSNR). Moreover, comparisons were conducted on the digestive tract of swine, and the results show that CCE-CS is also feasible in the in-vitro environment. These results demonstrated that CCE-CS method has good potential for application to improve the imaging quality of HFEUS while reducing the sampling rate.

Performance of Ultrasound for Identifying Morphological Characteristics and Thickness of Cutaneous Basal Cell Carcinoma: A Systematic Review

Advances in ultrasound technology and non-surgical treatments of basal cell carcinomas (BCCs) have raised the need to study the performance of high-frequency ultrasound (HFUS) in BCCs. We aimed to assess the performance of HFUS in the evaluation of BCCs to formulate recommendations for its uses and conducted a systematic review of the literature to do so. A search of Central, Medline, Embase, CINHAL, and Web of Science was performed using key/MESH terms "ultrasonography" and "basal cell carcinoma" (January 2005-December 2020). We included primary studies reporting biopsy-confirmed BCCs for which the target intervention was ultrasound assessment at 15 MHz or higher frequency. Thirty articles were included, studying a total of 1,203 biopsy-confirmed BCCs. HFUS provides accurate depth measurements, especially for BCCs >1 mm. The definition of lateral margins in vivo needs further studies; however, ex vivo margin assessment seems convincing. There is a diagnostic role for HFUS in identifying higher recurrence risk BCC subtypes, which can help in risk stratification. Performance of HFUS is significant in BCC management. Pre-surgical scans may support case selection for Mohs. HFUS can improve safety when used to plan brachytherapy treatments, help with case selection and adjunct treatment choice pre-photodynamic therapy. Finally, HFUS can help follow lesions after intervention, particularly non-surgical management, and support the decision to observe or re-intervene. HFUS can enhance clinical practice by providing useful information that cannot be deducted from the clinical examination. It would be recommended to evaluate the extent, mainly depth, and detect the aggressiveness of the BCCs.

Collapse pressure measurement of single hollow glass microsphere using single-beam acoustic tweezer

Microbubbles are widely used in medical ultrasound imaging and drug delivery. Many studies have attempted to quantify the collapse pressure of microbubbles using methods that vary depending on the type and population of bubbles and the frequency band of the ultrasound. However, accurate measurement of collapse pressure is difficult as a result of non-acoustic pressure factors generated by physical and chemical reactions such as dissolution, cavitation, and interaction between bubbles. In this study, we developed a method for accurately measuring collapse pressure using only ultrasound pulse acoustic pressure. Under the proposed method, the collapse pressure of a single hollow glass microsphere (HGM) is measured using a high-frequency (20-40 MHz) single-beam acoustic tweezer (SBAT), thereby eliminating the influence of additional factors. Based on these measurements, the collapse pressure is derived as a function of the HGM size using the microspheres' true density. We also developed a method for estimating high-frequency acoustic pressure, whose measurement using current hydrophone equipment is complicated by limitations in the size of the active aperture. By recording the transmit voltage at the moment of collapse and referencing it against the corresponding pressure, it is possible to estimate the acoustic pressure at the given transmit condition. These results of this study suggest a method for quantifying high-frequency acoustic pressure, provide a potential reference for the characterization of bubble collapse pressure, and demonstrate the potential use of acoustic tweezers as a tool for measuring the elastic properties of particles/cells.

Automated segmentation of epidermis in high-frequency ultrasound of pathological skin using a cascade of DeepLab v3+ networks and fuzzy connectedness

This study proposes a novel, fully automated framework for epidermal layer segmentation in different skin diseases based on 75 MHz high-frequency ultrasound (HFUS) image data. A robust epidermis segmentation is a vital first step to detect changes in thickness, shape, and intensity and therefore support diagnosis and treatment monitoring in inflammatory and neoplastic skin lesions. Our framework links deep learning and fuzzy connectedness for image analysis. It consists of a cascade of two DeepLab v3+ models with a ResNet-50 backbone and a fuzzy connectedness analysis module for fine segmentation. Both deep models are pre-trained on the ImageNet dataset and subjected to transfer learning using our HFUS database of 580 images with atopic dermatitis, psoriasis and non-melanocytic skin tumors. The first deep model is used to detect the appropriate region of interest, while the second stands for the main segmentation procedure. We use the softmax layer of the latter twofold to prepare the input data for fuzzy connectedness analysis: as a reservoir of seed points and a direct contribution to the input image. In the experiments, we analyze different configurations of the framework, including region of interest detection, deep model backbones and training loss functions, or fuzzy connectedness analysis with parameter settings. We also use the Dice index and epidermis thickness to compare our results to state-of-the-art approaches. The Dice index of 0.919 yielded by our model over the entire dataset (and exceeding 0.93 in inflammatory diseases) proves its superiority over the other methods.

Feasibility of endoscopic ultrasonography using a 60-MHz ultrasound miniature probe in the upper gastrointestinal tract

PURPOSE

The use of higher frequencies in ultrasound allows for a more detailed image. This study aimed to investigate the feasibility of delineating the gastrointestinal wall using a 60-MHz miniature ultrasound probe.

METHODS

A phantom study was performed using a multipurpose ultrasonic phantom model, and the depth of imaging was evaluated using 60-MHz and 20-MHz miniature probes and 7.5-MHz conventional convex-type endoscopic ultrasonography. A total of 25 visualized areas from a total of 16 specimens from 16 patients were enrolled. The structures of the layers of the esophagus, stomach, and duodenum were evaluated using a 60-MHz probe and a pathological specimen created from endoscopically or surgically resected specimens.

RESULTS

The 60-MHz probe was able to render to a depth of 2 mm and visualize the esophagus, stomach, and duodenum in five layers, respectively, within the depiction range. The depiction ranges of the 20-MHz probe and 7.5-MHz conventional endoscopic ultrasonography were 5 mm and 60 mm, respectively. The 60-MHz probe visualized the muscularis mucosae as the fourth layer in the esophagus, the fourth layer in the stomach, and the second layer in the duodenum. Muscularis mucosae were delineated in almost all cases, except in two cases where the layered structure disappeared.

CONCLUSION

The 60-MHz probe provided good visualization of the muscularis mucosae and structure of the layers down to the submucosa, which improves the ability to diagnose the depth of early cancer invasion of the upper gastrointestinal tract, leading to more appropriate treatments.

Mechanism of low-frequency and high-frequency ultrasound-induced inactivation of soy trypsin inhibitors

In this study, the effect of ultrasonic frequency and power on the inactivation of soy trypsin inhibitors (TIs) was investigated to explore the ultrasound-induced inactivation mechanism. It was observed that 20 kHz and 355 kHz ultrasound have better inactivation efficiency than 1056 kHz. First-order rate constants for the inactivation process were obtained, which increased with increasing ultrasonic power at both 20 kHz and 355 kHz. For 20 kHz ultrasound, the formation of TI aggregates resulting from the physical effects of acoustic cavitation decreased the interactions between the active sites of TIs and trypsin, thus reducing the TI activity. For 355 kHz ultrasound, most of the methionine in the TIs was oxidised within 5 mins, resulting in a faster reduction of TI activity. Subsequent aggregation of TIs resulted in further TI inactivation. SDS-PAGE showed that neither disulphide bonds nor CC coupling were involved in the formation of aggregates.

Diagnosis of Carpal Tunnel Syndrome using Shear Wave Elastography and High-frequency Ultrasound Imaging

OBJECTIVES

The performance of ultrasound features from shear wave elastography (SWE) and high-frequency ultrasound imaging was evaluated independently and in combination to diagnose carpal tunnel syndrome (CTS).

MATERIALS AND METHODS

Twenty-five subjects were imaged in a sitting position with an arm extended and palm facing up. SWE of the medial nerve (MN) was acquired at the wrist level (site 1) and proximal to the pronator quadratus muscle (site 2). Cross-sectional area (CSA) and vascularity of the MN were assessed at the wrist using a 24 MHz probe. Color and power Doppler imaging (CDI and PDI), monochrome and color-coded Superb Microvascular Imaging (SMI) were performed for vascularity assessments. The diagnosis and severity of CTS was determined by clinical and electrodiagnostic tests. Diagnostic performance of the ultrasound features was assessed by t-tests, ANOVAs, and ROC analysis.

RESULTS

The study included 20 control hands and 27 hands with CTS. All ultrasound features except for the stiffness ratio were significantly different between the CTS and control wrists (p<0.04). The stiffness of MN at site 1 showed a higher accuracy than at site 2. The combination of CSA and MN stiffness from site 2 showed an overall accuracy of 95% with a specificity and sensitivity of 100% and 93%, respectively. The CSA, MN stiffness from site 2, and CDI combination improved the accuracy to 96% with specificity and sensitivity of 100% and 93%, respectively. However, no ultrasound features (independently or in combination) differentiated all stages of CTS severity.

CONCLUSIONS

SWE with high-frequency ultrasound imaging showed potential for the diagnosis of CTS.

Regional variation of corneal stromal deformation measured by high-frequency ultrasound elastography

The cornea's mechanical response to intraocular pressure elevations may alter in ectatic diseases such as keratoconus. Regional variations of mechanical deformation in normal and keratoconus eyes during intraocular pressure elevation have not been well-characterized. We applied a high-frequency ultrasound elastography technique to characterize the regional deformation of normal and keratoconus human corneas through the full thickness of corneal stroma. A cross-section centered at the corneal apex in 11 normal and 2 keratoconus human donor eyes was imaged with high-frequency ultrasound during whole globe inflation from 5 to 30 mmHg. An ultrasound speckle tracking algorithm was used to compute local tissue displacements. Radial, tangential, and shear strains were mapped across the imaged cross-section. Strains in the central (1 mm surrounding apex) and paracentral (1 to 4 mm from apex) regions were analyzed in both normal and keratoconus eyes. Additional regional analysis was performed in the eye with severe keratoconus presenting significant thinning and scarring. Our results showed that in normal corneas, the central region had significantly smaller tangential stretch than the paracentral region, and that within the central region, the magnitudes of radial and shear strains were significantly larger than that of tangential strain. The eye with mild keratoconus had similar shear strain but substantially larger radial strains than normal corneas, while the eye with severe keratoconus had similar overall strains as in normal eyes but marked regional heterogeneity and large strains in the cone region. These findings suggested regional variation of mechanical responses to intraocular pressure elevation in both normal and keratoconus corneas, and keratoconus appeared to be associated with mechanical weakening in the cone region, especially in resisting radial compression. Comprehensive characterization of radial, tangential, and shear strains through corneal stroma may provide new insights to understand the biomechanical alterations in keratoconus.

Value of High-Frequency Ultrasound for Differentiating Invasive Basal Cell Carcinoma from Non-invasive Types

The purpose of the study was to evaluate the value of high-frequency ultrasound (HFUS) for differentiating invasive basal cell carcinomas (BCCs) from non-invasive BCCs. We established a prediction model based on ultrasound features and validated it further. One hundred patients in the pilot cohort and another 43 in the validation cohort were evaluated. All patients underwent HFUS examinations by the same radiologist, and then were divided on the basis of pathology into invasive and non-invasive types. With respect to growth pattern, 60.5% of invasive BCCs had an irregular pattern, whereas 89.5% of non-invasive BCCs had a nodular or crawling pattern (p < 0.001). As for the layers involved, the more invasive BCCs broke through the dermis compared with non-invasive BCCs (23.3% vs. 1.8%) (p < 0.001). With respect to intralesional hyperechoic spot distribution, invasive and non-invasive BCCs tended to be clustered and absent/scattered-like, respectively (55.8% vs. 91.2%) (p < 0.001). On the basis of the aforementioned features, a prediction model was established with accuracies of 84.0% and 76.7%, respectively, in the pilot and validation cohorts. HFUS holds promise for the differentiation of the invasiveness of BCCs and is helpful in its clinical management.

The diagnostic value of high-frequency ultrasound combined with color Doppler ultrasound versus surgical pathology in gallbladder polyps

OBJECTIVE

This study aimed to analyze the value of high-frequency ultrasound combined with color Doppler ultrasound in the diagnosis of gallbladder polyps.

METHODS

A retrospective analysis was performed on 108 patients with gallbladder polyps, all of whom were examined by high-frequency ultrasound and color Doppler ultrasound with surgical or pathological findings as the gold standard.

RESULTS

Taking surgical pathology findings as the gold standard, the diagnostic accuracy, sensitivity and specificity of high-frequency ultrasound for gallbladder polyps were 63.89%, 63.27%, and 70.00%, respectively. The diagnostic accuracy, sensitivity and specificity of color Doppler ultrasound were 74.07%, 73.47%, and 80.00%, respectively. The diagnostic accuracy, sensitivity and specificity of high-frequency ultrasound combined with color Doppler ultrasound were 91.67%, 90.82%, and 100.00%, respectively. The proportion of mulberry-like or papillary projections was 56.18% in 89 benign lesions diagnosed by high-frequency ultrasound combined with color Doppler ultrasound, the proportion of hyperechoic lesion was 47.19%, and the proportion of single lesion was 59.55%. The incidence rate of blood flow signal was 26.97% in 89 benign lesions, including 10 cases of punctiform blood flow signal, 9 cases of band-like blood flow signal and 5 cases of multiple stones in the lumen of the gallbladder.

CONCLUSION

High-frequency ultrasound combined with color Doppler ultrasound has high accuracy in the diagnosis of gallbladder polyps, and can yield better diagnostic results than either method, which can be used as an optional method for the diagnosis of gallbladder polyps.

Intraoperative surgical strategy changes in patients with chronic and end-stage renal disease undergoing coronary artery bypass grafting

OBJECTIVES

Factors such as more diffuse atherosclerosis, plaque instability and accelerated vascular calcification in patients with chronic and end-stage renal disease (ESRD) can potentially present intraoperative challenges in coronary artery bypass grafting (CABG) procedures. We evaluated whether patients with chronic and ESRD experienced more surgical strategy changes and/or graft revisions than patients with normal renal function when undergoing CABG procedures according to a protocol for intraoperative high-frequency ultrasound and transit-time flow measurement (TTFM).

METHODS

Outcomes of CABG for patients with chronic and ESRD and patients with normal renal function enrolled in the multicentre prospective REQUEST (REgistry for QUality assESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery) study were compared retrospectively. The primary end point was frequency of intraoperative surgical strategy changes. The secondary end point was post-protamine TTFM parameters.

RESULTS

There were 95 patients with chronic and ESRD and 921 patients with normal renal function. Patients with chronic and ESRD undergoing CABG according to a protocol for intraoperative high-frequency ultrasound and TTFM had a higher rate of strategy changes overall [33.7% vs 24.3%; odds ratio (OR) = 1.58; 95% confidence interval (CI) = 1.01-2.48; P = 0.047] and greater revisions per graft (7.0% vs 3.4%; odds ratio = 2.14; 95% CI = 1.17-3.71; P = 0.008) compared to patients with normal renal function. Final post-protamine graft TTFM parameters were comparable between cohorts.

CONCLUSIONS

Patients with chronic and ESRD undergoing CABG procedures with high-frequency ultrasound and TTFM experience more surgical strategy changes than patients with normal renal function while achieving comparable graft flow.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02385344.

Intraoperative transit-time flow measurement and high-frequency ultrasound in coronary artery bypass grafting: impact in off versus on-pump, arterial versus venous grafting and cardiac territory grafted

OBJECTIVES

Despite society guideline recommendations, intraoperative high-frequency ultrasound (HFUS) and transit-time flow measurement (TTFM) use in coronary artery bypass grafting (CABG) has not been widely adopted worldwide. This retrospective review of the REQUEST (REgistry for QUality assESsmenT with Ultrasound Imaging and TTFM in Cardiac Bypass Surgery) study assesses the impact of protocolled high-frequency ultrasound/TTFM use in specific technical circumstances of CABG.

METHODS

Three REQUEST study sub-analyses were examined: (i) For off-pump (OPCAB) versus on-pump (ONCAB) procedures: strategy changes from preoperative plans for the aorta, conduits, coronary targets and graft revisions; and for all REQUEST patients, revision rates in: (ii) arterial versus venous grafts; and (iii) grafts to different cardiac territories.

RESULTS

Four hundred and two (39.6%) of 1016 patients undergoing elective isolated CABG for multivessel disease underwent OPCAB procedures. Compared to ONCAB, OPCAB patients experienced more strategy changes regarding the aorta [14.7% vs 3.4%; odds ratios (OR) = 4.03; confidence interval (CI) = 2.32-7.20], less regarding conduits (0.2% vs 2.8%; OR = 0.09; CI = 0.01-0.56), with no differences in coronary target changes or graft revisions (4.1% vs 3.5%; OR = 1.19; CI = 0.78-1.81). In all REQUEST patients, revisions were more common for arterial versus venous grafts (4.7% vs 2.4%; OR = 2.05; CI = 1.29-3.37), and inferior versus anterior (5.1% vs 2.9%; OR = 1.77; CI = 1.08-2.89) and lateral (5.1% vs 2.8%; OR = 1.83; CI = 1.04-3.27) territory grafts.

CONCLUSIONS

High-frequency ultrasound/TTFM use differentially impacts strategy changes and graft revision rates in different technical circumstances of CABG. Notably, patients undergoing OPCAB experienced 4 times more changes related to the ascending aorta than ONCAB patients. These findings may indicate where intraoperative assessment is most usefully applied.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT02385344.

Cold Atmospheric Plasma (CAP) for the Treatment of Actinic Keratosis and Skin Field Cancerization: Clinical and High-Frequency Ultrasound Evaluation

INTRODUCTION

Cold atmospheric plasma (CAP) has been clinically demonstrated to be an effective treatment for actinic keratosis (AK) in a number of case series. In this study, we evaluated the efficacy of CAP in the treatment of multiple AKs and assessed morphological changes induced on the skin field of cancerization both clinically and by high-frequency ultrasound (HFUS).

METHODS

Patients with multiple grade I-II AKs of the scalp and/or face who were resistant or intolerant to conventional field-directed treatments were enrolled. CAP treatments were performed using a microwave-driven argon plasma jet. At baseline and 3 months after the last CAP session, performance indexes were determined using three-dimensional digital pictures and HFUS investigations were performed on a representative Olsen grade II AK and a small spot of clinically unaffected skin within the test area.

RESULTS

Twelve patients were enrolled in the study. All clinical variables showed a statistically significant reduction after CAP. HFUS evaluation revealed that the total, epidermal and dermal thicknesses of the target AKs had not changed with treatment. CAP therapy significantly increased dermal density in both the target AK and the surrounding photodamaged skin and signficantly decreased the thickness of the subepidermal low-echogenic band in the perilesional skin, which is an ultrasound sign of photodamage.

CONCLUSIONS

Cold atmospheric plasma was found to be an effective treatment for patients with multiple AKs. CAP was not followed by skin atrophy. HFUS examiniation showed the CAP improved features of chronic photodamage of the dermis of the skin underlying and surrounding the AK spots.

Diagnostic Value of Dynamic High-frequency Ultrasound for the Slipping Rib and Twelfth Rib Syndrome: A Case Series with Review

BACKGROUND

High-frequency ultrasound (HFUS) is a mobile, radiation-free imaging tool for the diagnosis of musculoskeletal disorders. We aim to demonstrate the diagnostic value of dynamic HFUS for undiagnosed lower chest, upper abdomen, and loin pain with this case series.

CASE SERIES

A cricketer presented with long-standing left-sided dull ache lower chest and upper abdominal pain, aggravated on exertion and leaning forward. His previous laboratory and previous imaging tests were unrevealing. Dynamic HFUS of his left ribs during hooking maneuver demonstrated slipping of the eighth rib over the seventh rib associated with clicking. He also reported tenderness over this region. He was diagnosed with slipping rib syndrome (SRS), and was treated with the eighth nerve block under the HFUS guidance. The second and third cases presented with chronic undiagnosed waxing and waning loin pain despite extensive laboratory and radiological workup. Both patients demonstrated twelfth rib HFUS probe tenderness in a sitting position with a specific movement that reproduced the pain during the dynamic HFUS study. The diagnosis of twelfth rib syndrome (TRS) was confirmed and treated successfully with a local intercostal nerve block.

REVIEW OF THE LITERATURE

HFUS is the most underutilized imaging tool for the diagnosis of unexplained upper abdominal and lower chest pain syndromes. We identified only a few such reported cases managed with the help of HFUS.

CONCLUSION

The dynamic HFUS is a valuable imaging modality for the undiagnosed lower chest, upper abdominal, or loin pain.

Ultra high-frequency ultrasound with seventy-MHz transducer in hair disorders: Development of a novel noninvasive diagnostic methodology

BACKGROUND

Ultra high-frequency ultrasound (uHFUS) is a recently developed diagnostic technology. Despite its potential usefulness, no study has assessed its advantage in diagnosis and evaluation of hair disorders in comparison with other diagnostic methods.

OBJECTIVES

To assess the practicability of uHFUS in diagnosing hair disorders and propose a diagnostic methodology.

METHODS

Ultrasonographic images of scalp and forehead from patients with hair disorders (n = 103) and healthy controls (n = 40) were obtained by uHFUS and analyzed by both descriptive and numerical parameters. Furthermore, the data were compared with trichoscopic and histopathological findings.

RESULTS

The pattern of inflammation and fibrosis, hair cycle abnormality, and the findings in subcutis were detected by uHFUS. Significant differences were noted in the numerical parameters associated with the number of hair shafts and follicles, hair diameters and their diversity, and dermal echogenicity in both cicatricial and non-cicatricial hair disorders. Findings in uHFUS were associated with those observed in trichoscopy and scalp biopsy but uHFUS was able to detect pathological findings associated with hair cycle, inflammation, fibrosis, and subcutaneous abnormalities, which are hardly assessable by trichoscopy.

CONCLUSION

The findings of this study highlighted usefulness of uHFUS in diagnosing hair disorders, while overcoming the weaknesses and limitations of other diagnostic tools.

High-frequency ultrasound in clinical dermatology: a review

Background

Ultrasound was first introduced in clinical dermatology in 1979. Since that time, ultrasound technology has continued to develop along with its popularity and utility.

Main text summary

Today, high-frequency ultrasound (HFUS), or ultrasound using a frequency of at least 10 megahertz (MHz), allows for high-resolution imaging of the skin from the stratum corneum to the deep fascia. This non-invasive and easy-to-interpret tool allows physicians to assess skin findings in real-time, enabling enhanced diagnostic, management, and surgical capabilities. In this review, we discuss how HFUS fits into the landscape of skin imaging. We provide a brief history of its introduction to dermatology, explain key principles of ultrasonography, and review its use in characterizing normal skin, common neoplasms of the skin, dermatologic diseases and cosmetic dermatology.

Conclusion

As frequency advancements in ultrasonography continue, the broad applications of this imaging modality will continue to grow. HFUS is a fast, safe and readily available tool that can aid in diagnosing, monitoring and treating dermatologic conditions by providing more objective assessment measures.

Quantitative characterization of the colorectal cancer in a rabbit model using high-frequency endoscopic ultrasound

PURPOSE

Colonoscopy accompanied with biopsy works as the routine endoscopic strategy for the diagnosis of colorectal cancer (CRC) in clinic; however, the colonoscopy is limited to the tissue surface. During the last decades, enabling technologies are emerging to complement with the colonoscopy for better administration of CRC. The conventional low-frequency (<12 MHz) endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) has been widely used to assess the lesion penetration. With the high-frequency ultrasound transducer (>20 MHz), EUS allows more precise visualization of the colorectal abnormalities. In order to achieve the accurate detection or in situ characterization of the colorectal lesions, the EUS diagnosis needs more patho-physiological related information in the micro-structural or molecular level. Quantitative ultrasound (QUS) technique, which could extract the micro-structural information from the ultrasound radio-frequency (RF) signal, is promising for the non-invasive tissue characterization. To date, the knowledge of the high-frequency endoscopic QUS for the CRC characterization has not been fully determined.

METHODS

In this work, to our best knowledge, it is the first application of the QUS technique based on a customized high-frequency EUS system (30.5 MHz center frequency) to characterize the colorectal malignancies in a VX2 rabbit CRC model. To eliminate the response from the ultrasound electronic system and transducer, the ultrasound signals from colon tissue were calibrated. And, the resulting quasi-liner ultrasound spectra were fit by the linear regression test. As a result, three spectral parameters, including the slope (k), intercept (I) and Midband Fit (M), were obtained from the best-fit line. The three spectral parameters were compared between the malignant tissue regions and adjacent normal tissue regions of the colon tissue specimen ex vivo. The independent t-test was conducted between the three parameters from the normal and malignant group. The statistical method of Fisher Linear Discriminant (FLD) was used to explore the linear combinations of the three parameters, so as to provide more tissue micro-structural features than the single parameter alone. The three FLD values were derived from three different combinations among k, I and M. The threshold was selected from the statistical analysis to optimize the differentiation criteria between the malignant and the normal tissues. The color-coded images were used to display the local FLD values and combined with the EUS B-mode image.

RESULTS AND CONCLUSIONS

The mean Midband Fit (M) and intercept (I) showed significant differences between the malignant and normal tissue regions. The statistical analysis showed that there were significant differences in all the mean FLD values of the spectral parameter combinations (kI, kM and IM) (t test, P < 0.05). And, the combined image result from the B-mode image and color-coded image could visually correlate with the histology result. In conclusion, the high-frequency endoscopic QUS technique was potential to be used as a complementary method to distinguish the colorectal malignancies by leveraging its morphological and micro-structural ultrasound information.

Combination of high-frequency ultrasound and virtual touch tissue imaging and quantification improve the diagnostic efficiency for mild carpal tunnel syndrome

Background

Carpal tunnel syndrome (CTS) is the most common entrapment symptom in the peripheral nerves. High-frequency ultrasound (HFUS) is widely used in the diagnosis of CTS. Virtual Touch Tissue Imaging and Quantification (VTIQ), which provides more information about the hardness of organization, is used to diagnose CTS. However, the data of diagnostic value of them in various degrees of CTS are limited. Whether the combination of HFUS and VTIQ can improve the diagnostic efficiency also remains unknown. The study aimed to explore the diagnostic value of HFUS and VTIQ in various degrees of CTS and whether combination of HFUS and VTIQ could improve the diagnostic efficiency of CTS.

Methods

A collection and analysis of 133 CTS patients and 35 volunteers from January 2016 to January 2019 were performed. We compared the clinical characteristics, cross-sectional area (CSA) value and shear wave velocity SWV_mean value of CTS group with volunteer group.

Results

The CSA value and SWV_mean value of CTS cohort were significantly higher than volunteer group (10.79 ± 2.88 vs. 8.06 ± 1.39, p < 0.001, 4.36 ± 0.95 vs. 3.38 ± 1.09, p < 0.001, respectively). The area under the curve (AUC) of receiver operating characteristic (ROC) curve of CSA value and SWV_mean value were 0.794 and 0.757, respectively. Hierarchical analysis of CSA value and SWV_mean value showed that the AUC in the moderate and severe CTS group were higher than in mild CTS group. Furthermore, the CSA value combined with SWV_mean value used to diagnose mild CTS was 0.758, which was higher than that of single CSA value or single SWV_mean value.

Conclusions

Both HFUS and VTIQ technology were feasible to evaluate CTS. HFUS was suitable for use in diagnosis of moderate and severe CTS. For mild CTS, combination of HFUS and VTIQ was relevant to improve the diagnostic efficiency of CTS.

A retrospective study to identify the optimal parameters for pulsed dye laser in the treatment of hypertrophic burn scars in Chinese children with Fitzpatrick skin types III and IV

For over several decades, 595-nm pulsed dye laser (PDL) has been used effectively, reducing erythema and improving the pliability and texture of burn scars. Children usually tolerate PDL treatment as it is non-invasive and causes only mild pain compared to other laser treatments. However, currently, there are limited data on scar management in children who underwent PDL treatment, especially for Fitzpatrick skin types III and IV. The objective of the study was to identify the optimal parameters for the PDL treatment that induce inhibitory effects on scar tissue in children with Fitzpatrick skin types III and IV. Besides, the study assessed the usefulness of high-frequency ultrasound (20 MHz) and laser Doppler flowmetry in assessing these lesions. A total of 165 (79 males and 86 females) children with hypertrophic scars treated by PDL were assessed by the Vancouver scar scale (VSS), high-frequency ultrasound (20 MHz), and laser Doppler flowmetry. The parameters used for the 595-nm PDL treatment were pulse duration of 0.45 ms, fluence between 5 and 9 J/cm², a spot size of 7 mm, and treatment intervals from 3 to 8 weeks. There were no significant differences between pretreatment and post-treatment in terms of the distribution of sex, type of skin color, and low and high fluences. While the mean scores of all scar parameters based on VSS, except thickness and pliability between pre and post-treatment, showed significant differences in ≤3-year-old children vs. to >3-year-old children, except for the subscore, a significant improvement was observed when PDL was initiated within 4 to 6 months of the scar age. In Chinese children with Fitzpatrick skin types III and IV, early intervention, appropriate treatment intervals, and low fluence of PDL were optimal parameters in treating hypertrophic burn scars. The combined high-frequency ultrasound and laser Doppler flowmetry assessment of scars helped assess these lesions and compare the efficacy of different treatment modalities.

Photoacoustic and high-frequency ultrasound imaging of systemic sclerosis patients

Introduction

Systemic sclerosis starts with an early phase characterized by Raynaud’s phenomenon, puffy fingers/hands, autoantibodies, and a scleroderma nailfold microscopic pattern. Alterations in the nailfold microscopic pattern are not evident in all early SSc patients. Photoacoustics (PA) and high-frequency ultrasound (HFUS) could fulfill this need. The former can measure oxygen saturation while the latter can measure skin thickening. We hypothesize that photoacoustics and high-frequency ultrasound can distinguish (early) SSc patients from individuals with primary Raynaud’s phenomenon (PRP) by measuring oxygenation of the fingertip and skin thickening.

Methods

We compared measurements of oxygenation and skin thickness of the third finger between (early) SSc patients and PRP individuals and healthy controls. The spearman rank correlation was used to analyze an association between capillary density and oxygen saturation of the fingers.

Results

Thirty-one adult subjects participated in this study: twelve patients with SSc, 5 patients with early SSc, 5 volunteers with PR, and 9 healthy controls.

We found a significant difference in oxygen saturation between (early) SSc patients (80.8% ± 8.1 and 77.9% ± 10.5) and individuals with PRP (93.9% ± 1.1).

Measurements of skin thickening showed a significant difference in (early) SSc patients compared to individuals with PRP (0.48 ± 0.06 mm and 0.51 ± 0.16 mm vs. 0.27 ± 0.01 mm). There was no significant difference between healthy and PRP individuals in oxygenation or skin thickening.

Conclusion

Photoacoustic and high-frequency ultrasound could help to distinguish between (early) SSc, PRP, and healthy individuals in both oxygenation and skin thickening.

[Thickness of A1 Pulley Measured by High-frequency Ultrasound and Its Influence Factors in Healthy Volunteers]

OBJECTIVE

To investigate A1 pulley thickness of flexor tendon in healthy volunteers and to analyze its influence factors.

METHODS

The study included 90 healthy volunteers and the A1 pulley thickness at bilateral fingers was measured using high frequency ultrasound. The following parameters were recorded for each participant: age, gender, weight, height, body mass index (BMI).

RESULTS

High-frequency ultrasound can clearly show A1 pulley. There was no significant difference in A1 pulley thickness between the bilateral fingers ( P>0.05). A1 pulley thickness was significantly different in different fingers ( P<0.05). Further comparison showed that A1 pulley thickness could be divided into two subsets: thumb and little finger ((0.196±0.051) mm), index, middle and ring fingers ((0.230±0.055) mm). A1 pulley thickness was positively correlated with age ( r=0.468, P<0.001). The normal reference ranges for thumb and little finger were 0.09-0.23 mm, 0.12-0.30 mm and 0.12-0.32 mm, respectively. The normal reference ranges for index, middle and ring fingers were 0.11-0.27 mm, 0.15-0.35 mm and 0.17-0.35 mm in volunteers aged 3-19 yr., 20-49 yr., and ≥50 yr., respectively. Gender and BMI had negligible impact on A1 pulley thickness ( P>0.05).

CONCLUSION

High-frequency ultrasound can clearly show and measure A1 pulley. Site and age should be taken into account when determining the reference range of normal A1 pulley thickness. High-frequency ultrasound can be a quantitative evaluation method for A1 pulley lesions.

HFUS Imaging of the Cochlea: A Feasibility Study for Anatomical Identification by Registration with MicroCT

Cochlear implantation consists in electrically stimulating the auditory nerve by inserting an electrode array inside the cochlea, a bony structure of the inner ear. In the absence of any visual feedback, the insertion results in many cases of damages of the internal structures. This paper presents a feasibility study on intraoperative imaging and identification of cochlear structures with high-frequency ultrasound (HFUS). 6 ex-vivo guinea pig cochleae were subjected to both US and microcomputed tomography (µCT) we respectively referred as intraoperative and preoperative modalities. For each sample, registration based on simulating US from the scanner was performed to allow a precise matching between the visible structures. According to two otologists, the procedure led to a target registration error of 0.32 mm ± 0.05. Thanks to referring to a better preoperative anatomical representation, we were able to intraoperatively identify the modiolus, both scalae vestibuli and tympani and deduce the location of the basilar membrane, all of which is of great interest for cochlear implantation. Our main objective is to extend this procedure to the human case and thus provide a new tool for inner ear surgery.

Essential oils microemulsions prepared with high-frequency ultrasound: physical properties and antimicrobial activity

Essential oils (EOs) have demonstrated antimicrobial activity against bacteria due to the effects of their major components. The direct application of EOs may present a rapid volatilization of its components and can decrease their effectiveness. Encapsulation by means of emulsification can provide protection to lipid compounds on a microscale. The aim of this study was to characterize microemulsions of cinnamon essential oil (CEO), oregano essential oil (OEO), and rosemary essential oil (REO) prepared by high-frequency ultrasound and evaluate their antimicrobial activities against Escherichia coli and Listeria monocytogenes. The microemulsions (oil-in-water, O/W) of EOs were prepared using high-frequency ultrasound, applying a wave amplitude of 84 µm for 15 min (REO and CEO) or 30 min (OEO). The antimicrobial activity was determined by inoculating 10⁸ CFU/mL of bacteria. Nonsurvival of the bacteria was confirmed by plate count in tryptic soy agar, determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The microemulsions exhibited droplet size diameters of 1.98 to 5.46 µm, showing high encapsulation efficiencies (79.91-81.97%) and low separation rates (2.50-6.67%). The MIC and MBC for the microemulsions for both bacteria were 20-75% less than values obtained for the non-encapsulated EOs. This study demonstrates that high-frequency ultrasound is a suitable technique for obtaining stable microemulsions to deliver natural antimicrobials that can be applied to control bacteria of high relevance in food safety.

Left atrial maze procedure using diathermy and high-frequency ultrasound as an adjunct to mitral valve replacement in mitral valve disease with atrial fibrillation: a comparative study

Purpose

Mitral valve disease is often complicated with atrial fibrillation (AF). Conventional treatment for AF has now been replaced by various energy sources. Our purpose was to evaluate a cost-effective and efficient energy source for performing the Maze procedure. We evaluated and compared diathermy and high-frequency ultrasound as energy source to create maze lines, in terms of outcome.

Methods

Forty patients with mitral valve disease requiring mitral valve replacement and in atrial fibrillation were included in the study. Twenty patients underwent the Maze procedure using diathermy and 20 using high-frequency ultrasound (Harmonic scalpel probe). All Maze lines were made endocardially from within the cavum of the left atrium isolating the pulmonary veins. All patients were assessed by standard 12 lead electrocardiogram (ECG) in the postoperative period as well as in each follow up visit. Left atrial appendage was ligated in those having left atrium (LA) clot.

Results

Sinus rhythm was restored in 95% of patients in the immediate postop period in diathermy group as compared to 90% in the high-frequency ultrasound group. At 3 months, 90% were in sinus rhythm in the diathermy group and 85% in the high frequency ultrasound (HFU) group. Statistically significant differences between groups were observed in the following variables: cardiopulmonary bypass (CPB) time (p = 0.011), cross clamp time (p = 0.019), maze time (p = 0.00), and in hospital stay (p = 0.05).

Conclusion

Both energy sources were safe, time sparing, effective, and simple; however, the diathermy took less time to perform maze than the HUF and the total CPB time and cross clamp time was less in the diathermy group.

[Research value of 50 MHz high-frequency ultrasound on sonography of normal facial skin in adult]

Objective: To observe the differences in normal facial skin thickness and echo density by different ages and sites of healthy adults of the same sex using 50 MHz high-frequency ultrasound. Methods: From January to June 2019, 200 healthy adult volunteers with normal facial skin who were from Sichuan, Yunnan, Guizhou, and Chongqing and met the inclusion criteria were recruited by the Affiliated Hospital of Southwest Medical University with simple random sampling method, and then were included in this cross-sectional investigation study. Then 50 MHz high-frequency ultrasound was used to obtain skin ultrasonogram of volunteers' forehead, canthus, eyelid, and cheek. According to the ages, 100 female volunteers were divided into 20-29 years old (30 females), 30-39 years old (25 females), 40-49 years old (20 females), and 50-70 years old (25 females) groups; 100 male volunteers were divided into 20-29 years old (30 males), 30-39 years old (25 males), 40-49 years old (20 males), and 50-70 years old (25 males) groups. The thickness of full-skin, the upper dermal echo density, and the lower dermal echo density of the female and male volunteers'forehead, canthus, eyelid, and cheek were recorded respectively. Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, least significant difference test, and Bonferroni correction. Results: (1) The thickness of full-thickness skin in forehead, canthus, eyelid, and cheek of female and male volunteers in 20-29 years old group were (1.86±0.26), (1.36±0.11), (1.24±0.25), and (1.90±0.21) mm, (2.45±0.37), (1.64±0.19), (1.44±0.16), and (2.53±0.26) mm, respectively, in 30-39 years old group were (1.98±0.24), (1.43±0.13), (1.15±0.15), and (2.12±0.13) mm, (2.34±0.27), (1.63±0.27), (1.50±0.38), and (2.43±0.40) mm, respectively, in 40-49 years old group were (1.90±0.21), (1.43±0.18), (1.24±0.27), and (1.98±0.12) mm, (2.14±0.24), (1.54±0.25), (1.28±0.14), and (2.39±0.36) mm, respectively, in 50-70 years old group were (1.64±0.25), (1.36±0.19), (1.16±0.12), and (1.89±0.29) mm, (2.28±0.27), (1.73±0.25), (1.58±0.18), and (2.38±0.32) mm, respectively. There were no statistically significant differences between female volunteers in the 4 groups and male volunteers in the 4 groups in thickness of full-thickness skin in canthus, eyelid, and cheek (F=0.677, 0.666, 0.136, 0.697, 0.294, 0.888, P>0.05). The thickness of full-thickness skin in forehead and cheek of the female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05), and was significantly higher than that of canthus and eyelid (P<0.05). The thickness of full-thickness skin in canthus and eyelid of female volunteers in 20-29 years old, 40-49 years old, and 50-70 years old group was similar (P>0.05), while thickness of full-thickness skin in canthus and eyelid of male volunteers in the 4 groups was similar (P>0.05). (2) The upper dermal echo density of forehead, canthus, eyelid, and cheek of female volunteers in 50-70 years old group was significantly lower than that in 20-29 years old and 30-39 years old groups (P<0.05). The upper dermal echo density of forehead, canthus, eyelid, and cheek of male volunteers in 50-70 years old group was significantly lower than that in 20-29 years old group (P<0.05). The upper dermal echo density of forehead, canthus, eyelid, and cheek of female and male volunteers in 20-29 years old and 30-39 years old groups was similar (P>0.05). The upper dermal echo density of forehead and cheek of female volunteers in 20-29 years old, 40-49 years old, and 50-70 years old groups was significantly lower than that of canthus and eyelid (P<0.05). The echo density of upper dermis of cheek of male volunteers in the 4 groups was significantly lower than that of canthus and eyelid (P<0.05). The upper dermal echo density of canthus and eyelid of female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05), the upper dermal echo density of forehead and cheek was similar (P>0.05). (3) The lower dermal echo density of forehead, canthus, eyelid, and cheek of female volunteers in 50-70 years old group was significantly higher than that in 20-29 years old and 30-39 years old groups (P<0.05). The lower dermal echo density of forehead, canthus, eyelid, and cheek of male volunteers in 50-70 years old group was significantly higher than that in 20-29 years old group (P<0.05). The echo density of the lower dermis of forehead, eyelid, and cheek of female and male volunteers in 20-29 years old, 30-39 years old, and 40-49 years old groups was similar (P>0.05). The lower dermal echo density of forehead and cheek of female volunteers in the 4 groups was significantly lower than that of canthus and eyelid (P<0.05). The lower dermal echo density of forehead and cheek of male volunteers in 30-39 years old, 40-49 years old, and 50-70 years old groups was significantly lower than that of canthus and eyelid (P<0.05). The lower dermal echo density between canthus and eyelid and between forehead and check of female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05). Conclusions: The 50 MHz high-frequency ultrasonography shows that the thickness of full-thickness skin of canthus, eyelid, and cheek is similar in all age groups of female and male adult volunteers with normal facial skin. In the same age group, the thickness of full-thickness skin of forehead and cheek of male and female volunteers is significantly higher than that of canthus and eyelid. The upper dermal echo density of forehead, canthus, eyelid, and cheek of female and male volunteers shows a decreasing trend with age, while the lower dermal echo density shows an increasing trend with age. In addition, the echo density of upper and lower dermis of canthus and eyelid was significantly higher than that of cheek in all the four age groups.

Imaging digital arteries in systemic sclerosis by tomographic 3-dimensional ultrasound

Objective methods are needed to quantify digital artery disease in systemic sclerosis (SSc) for clinical trials of vascular therapies. Our primary aim was to examine feasibility of a novel tomographic three-dimensional-(3-D) ultrasound (tUS) with high-frequency ultrasound (HFUS) or ultra-high-frequency ultrasound (UHFUS) to assess the digital arteries in patients with SSc compared to healthy controls. A secondary objective was to compare the total wall volume (TWV) as a measure of intimal/medial thickness. Eighteen patients with a confirmed diagnosis of SSc were studied by tUS HFUS (17.5 MHz, n = 10) or tUS UHFUS (48 and 70 MHz, n = 8) with equal numbers of healthy controls of similar age and gender. The majority of patients had limited cutaneous SSc and were representative of a spectrum of digital vasculopathy, with over half (n = 6 HFUS and n = 5 UHFUS) having previous digital ulceration. Over half were receiving oral vasodilatory therapy. TWV was measured in both digital arteries of the middle finger bilaterally. At least, two digital arteries could be identified at 17.5 MHz in all patients and healthy controls. Whereas, at least two digital arteries could be identified in relatively fewer patients compared to healthy controls using 48 MHz (n = 6 and 10) and especially 70 MHz (n = 4 and 10) UHFUS. The median difference in TWV between patients and healthy controls was -6.49 mm³ using 17.5 MHz, 1.9 mm³ at 48 MHz, and -0.4 mm³ at 70 MHz. tUS using UHFUS is a feasible method to measure TWV of digital arteries in SSc. Transducer frequency plays an important factor in successful digital artery measurement, with 48 MHz being the optimal frequency.