European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Position Statement on Dermatologic Ultrasound

Advances in image-based diagnosis of nail disorders

This paper provides a comprehensive overview of image-based techniques, particularly focusing on their applications and advancements in the context of nail disorders. Nowadays, high-resolution digital cameras and dermoscopes enable dermatologists to capture detailed images of nail abnormalities, facilitating early diagnosis and meticulous tracking of disease progression. Onychoscopy is now a routine technique with well-known criteria for the diagnosis, but recent developments allow us to visualize certain diseases better. Imaging modalities like high-frequency ultrasound, magnetic resonance imaging, optical coherence tomography and confocal microscopy are being increasingly adopted for their superior diagnostic capabilities. These techniques are described in their technology, scanning protocols, normal findings, advantages and limitations. Moreover, the integration of technology in patient education has fostered a more informed patient population, capable of actively participating in their disease monitoring and treatment regimens. Proper training, validation, regulation and ethical considerations are, however, essential when integrating technology into healthcare practices. Imaging technologies that present the potential to add critical anatomical information to clinical diagnoses within reasonable costs and are available worldwide are the ones that will probably be used the most.

Update on the role of color Doppler ultrasound in hidradenitis suppurativa: a game-changer

Hidradenitis suppurativa has greatly benefited from the insights of color Doppler ultrasound. Thus, ultrasonography has helped prove the follicular link of this disease and has ruled out the primary involvement of the apocrine glands, which, in the old days, was supposedly the cause of the disease. Importantly, ultrasound can detect subclinical anatomical information in HS that cannot be deducted from the clinical examination. Moreover, high-frequency (≥15 MHz) and ultra-high-frequency (≥50 MHz) ultrasound present a much higher axial spatial resolution compared to magnetic resonance imaging. Ultrasound allows us to detect better subclinical cutaneous anatomical abnormalities and, therefore, arrive earlier and more accurately at diagnosis and staging. Ultrasonographic diagnostic criteria can discriminate HS from other clinical simulators, which is also critical in diagnosing mild and moderate stages and is relevant for the severe stages. This imaging technique supports the severity (mSOS-HS) and activity (US-HSA) scorings more accurately, which can help assess the actual stage of the disease. This is important to decide the type of treatment and to perform a more objective follow-up of the patients. Magnetic resonance imaging has been reported as helpful in diagnosing deep perianal tunnels; however, it presents a lower axial spatial resolution compared with high and ultra-high frequency ultrasound. Nowadays, there is solid evidence of the usefulness of ultrasound in HS, which implies that it is a game-changer and should be recommended as the first-choice imaging technique and a standard of care tool for HS patients.

High-Frequency Ultrasonography in Hair and Nail Disorders-How It May Be Helpful

Ultrasonography is a recognized method of tissue visualization in medicine, which is based on the use of mechanical waves (ultrasound). Its application in dermatology requires the use of higher frequencies, hence the use of high-frequency ultrasonography (HFUS) is recommended. HFUS has gained approval in many areas of dermatology, including imaging of skin appendages [nail unit (NU) and hair follicles]. The analysis of the changing echogenicity of structures under the influence of inflammatory and neoplastic processes is used to assess the extent of the disease, treatment planning as well as in monitoring therapeutic effects. The aim of our work is to present the possibilities of visualizing NUs and scalps with the use of HFUS.

Attention-Guided Learning With Feature Reconstruction for Skin Lesion Diagnosis Using Clinical and Ultrasound Images

Skin lesion is one of the most common diseases, and most categories are highly similar in morphology and appearance. Deep learning models effectively reduce the variability between classes and within classes, and improve diagnostic accuracy. However, the existing multi-modal methods are only limited to the surface information of lesions in skin clinical and dermatoscopic modalities, which hinders the further improvement of skin lesion diagnostic accuracy. This requires us to further study the depth information of lesions in skin ultrasound. In this paper, we propose a novel skin lesion diagnosis network, which combines clinical and ultrasound modalities to fuse the surface and depth information of the lesion to improve diagnostic accuracy. Specifically, we propose an attention-guided learning (AL) module that fuses clinical and ultrasound modalities from both local and global perspectives to enhance feature representation. The AL module consists of two parts, attention-guided local learning (ALL) computes the intra-modality and inter-modality correlations to fuse multi-scale information, which makes the network focus on the local information of each modality, and attention-guided global learning (AGL) fuses global information to further enhance the feature representation. In addition, we propose a feature reconstruction learning (FRL) strategy which encourages the network to extract more discriminative features and corrects the focus of the network to enhance the model's robustness and certainty. We conduct extensive experiments and the results confirm the superiority of our proposed method. Our code is available at: https://github.com/XCL-hub/AGFnet.

Skin ultrasound for rheumatologists: Technical issues and challenges

Introduction

In several rheumatic diseases, the skin is involved and therefore it is an organ of interest which may be investigated by the rheumatologist. Ultrasound imaging has been proposed for assessing multiple skin conditions providing qualitative and quantitative information about different parameters in distinct skin layers. Our aim was to describe with a pictorial essay the main challenges that the ultrasound imaging may encounter when investigating the healthy skin in different body areas.

Subjects and methods

Fourteen healthy subjects were submitted to skin ultrasound. The body areas that were investigated were decided following the 17 modified Rodnan skin score anatomical areas used in systemic sclerosis. Skin ultrasound was performed with a GE Logiq 10 with two probes (20 and 24 MHz). For an optimal quantification of the skin layers, the dermis interfaces either with the epidermis and hypodermis were investigated.

Results

The results of the ultrasound analysis are described and summarized in a pictorial essay which shows that some main factors may significantly influence the quality of the images of the skin layers. Specifically, age, scanning position, probe frequency, and the optimal positioning of some anatomical areas, in particular the hands and digits, emerged as factors that may have a relevance in influencing the quality of the imaging of the skin layers. Moreover, some technical suggestions are proposed to help optimizing and standardizing the performance of skin ultrasound assessment in healthy population.

Conclusion

The pictorial essay we performed shows that the performance of skin ultrasound in healthy subjects still presents several issues that need to be addressed. The definition of the interface in different body areas is the first step which should be standardized before any measurement of the thickness of the skin layers is performed in rheumatic diseases.

Essential Considerations for Radiologists in Diagnosing Hidradenitis Suppurativa

Hidradenitis suppurativa, also referred to as inverse acne, manifests as a persistent inflammatory skin disorder characterized by lesions such as deep nodules, abscesses, sinus tracts, and fibrotic scars. These manifestations predominantly occur in skin folds and intertriginous areas, notably in the axillary, inguinal, perianal, perineal, and inframammary regions. Due to similarities with other conditions in its initial stages, accurate diagnosis of hidradenitis suppurativa is often delayed, sometimes spanning several years. Diagnosis relies on identifying specific morphologic features (such as deep, inflamed, and painful nodules; sinus tracts; and scars), considering the affected sites (skin folds and areas with apocrine glands), and recognizing the chronic nature of the condition (persistent course with periods of exacerbation and remission). There are no definitive biologic or pathologic diagnostic tests, and biopsy of the affected area is not necessary. Treatment varies based on severity and may include topical and systemic antibiotics, hormonal therapy, immunomodulators, and surgery. Due to associated pain, increased site sensitivity, secretion drainage, odor, and scarring, this condition can have a negative psychosocial impact. Imaging studies, including high-frequency US and MRI with subsequent three-dimensional reconstruction, serve as valuable tools for precise staging, monitoring disease activity, and preoperative assessment. Currently, high-frequency US stands as the preferred method, incorporating sonographic classifications, while MRI and thee-dimensional imaging represent an emerging and promising approach. Imaging helps identify the extent of sinus tracts, assess involvement dimensions in advanced disease stages, and monitor proposed treatments. ©RSNA, 2024 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Advanced US of the Skin, Nerves, and Muscles of the Neck: Pearls and Pitfalls with Use of High-Frequency Transducers

High-frequency US provides excellent visualization of superficial structures and lesions, is a preferred diagnostic modality for anatomic characterization of neck abnormalities, and has a central role in clinical decision making. Recent technological advancements have led to the development of transducers that surpass 20 MHz, elevating high-frequency US to a highly valuable diagnostic tool with broader clinical use and enabling greater spatial resolution in the assessment of skin and superficial nerves and muscles. The authors focus on evolving applications of high-frequency US in neck imaging, emphasizing practical insights and strategies in skin and neuromuscular applications. ©RSNA, 2024 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Ultrasound in Skin Cancer: Why, How, and When to Use It?

BACKGROUND

Skin cancer is the most common cancer in human beings. Ultrasound is a powerful and non-invasive imaging technique that has expanded its use in dermatology, including in the skin cancer field. The full range of critical anatomical information provided by ultrasound cannot be deduced from a naked eye examination, palpation, or other imaging techniques such as dermoscopy, confocal microscopy, magnetic resonance imaging, or PET-CT (Positron Emission Tomography-Computed Tomography).

METHODS

This review practically analyzes the main ultrasonographic features of the most common types of skin cancers and the performance of the locoregional staging according to the literature, which is illustrated by state-of-the-art clinical and ultrasonographic correlations.

RESULTS

The most common types of skin cancer show recognizable ultrasonographic patterns.

CONCLUSIONS

Among the current radiological imaging techniques, ultrasound has the highest axial spatial resolution. Compared to other imaging techniques used in dermatology, it shows the great advantage of penetrating the soft tissues thoroughly, which allows us to detect and identify the most common skin types of skin cancer, including both the primary tumor and its locoregional metastases.

Role of high-frequency ultrasound in differentiating benign and malignant skin lesions: potential and limitations

PURPOSE

This study examined the diagnostic value of high-frequency ultrasound (HFUS) features in differentiating between benign and malignant skin lesions.

METHODS

A total of 1,392 patients with 1,422 skin lesions who underwent HFUS examinations were included in an initial dataset (cohort 1) to identify features indicative of malignancy. Qualitative clinical and HFUS characteristics were recorded for all lesions. To determine which HFUS and clinical features were suggestive of malignancy, univariable and multivariable logistic regression analyses were employed. The diagnostic performance of HFUS features combined with clinical information was evaluated. This assessment was validated using internal data (cohort 2) and multicenter external data (cohort 3).

RESULTS

Features significantly associated with malignancy included age above 60 years; lesion location in the head, face, and neck or genital regions; changes in macroscopic appearance; crawling or irregular growth pattern; convex or irregular base; punctate hyperechogenicity; blood flow signals; and feeding arteries. The area under the receiver operating characteristic curve, sensitivity, and specificity of HFUS features combined with clinical information were 0.946, 92.5%, and 86.9% in cohort 1; 0.870, 93.1%, and 80.8% in cohort 2 (610 lesions); and 0.864, 86.2%, and 86.6% in cohort 3 (170 lesions), respectively. However, HFUS is not suitable for evaluating lesions less than 0.1 mm in thickness or lesions exhibiting surface hyperkeratosis.

CONCLUSION

In a clinical setting, the integration of HFUS with clinical information exhibited good diagnostic performance in differentiating malignant and benign skin lesions. However, its utility was limited in evaluating extremely thin lesions and those exhibiting hyperkeratosis.

Role of Color Doppler Ultrasound in Cutaneous Inflammatory Conditions

Inflammatory cutaneous diseases can be challenging to diagnose and manage. Nowadays, the anatomical information provided by ultrasound is critical for detecting subclinical alterations and assessing the severity and activity of these conditions. Many of these entities can be clinically observed in dermatology and other specialties, such as rheumatology, plastic surgery, ophthalmology, and otolaryngology, among others. We review the ultrasonographic patterns of the most common inflammatory cutaneous conditions. In several cases, such as hidradenitis suppurativa, acne, and morphea, there are ultrasonographic staging systems of severity or activity that are pivotal in the management of these diseases. The early ultrasonographic diagnosis of these entities implies a proper management of the patients and, therefore, improve their quality of life. Thus, knowledge of the current use of ultrasound in this field seems essential.

Ultrasound of Skin Cancer: What We Need to Know

Ultrasound is an imaging technique that can provide critical anatomical information about malignant skin tumors that cannot be deducted by clinical examination, dermoscopy, or even biopsy. This data can support detecting and assessing the extent of the primary tumor and its differential diagnosis, surgical planning, and locoregional staging. Moreover, this non-invasive technique can help to follow-up and detect recurrences. This review aims to address the most common indications for ultrasound in skin oncology and provide a comprehensive guide to the grayscale and color-Doppler findings in cutaneous melanoma, squamous cell carcinoma, basal cell carcinoma, and other cutaneous malignant tumors.

Ultrasound Features of Nail Lichen Planus

OBJECTIVES

To describe the ultrasonographic features of nail lichen planus (NLP), which, so far, have not been reported in the literature.

METHODS

A retrospective single-center study of NLP patients' color Doppler ultrasound examinations was performed between March 2014 and January 2023. Inclusion criteria were patients ≥15 years with a confirmed clinical diagnosis of NLP in sequential order. Exclusion criteria included concomitant systemic or local cutaneous or nail diseases and systemic or local nail treatments before the ultrasound examination. The ultrasound protocol included the examination of all fingernails or toenails following the reported protocol for dermatologic ultrasound examinations at high and ultra-high frequencies. Patient demographics and ultrasound features of the nail bed, periungual region, nail plate, and regional vascularity were registered and analyzed statistically.

RESULTS

A total of 36 patients met the criteria. All cases presented thickened and decreased echogenicity of the nail bed. A hypoechoic halo surrounding the origin of the nail plate was present in 78% of cases. Exactly 58% of patients presented decreased echogenicity of the proximal periungual dermis, and 86% showed thickening of the periungual dermis. Hypervascularity of the nail bed was seen in 94% of cases. The mean maximum thickness of vessels, the peak systolic velocity of the arterial vessels, and other blood flow findings are provided.

CONCLUSION

Ultrasonography can support the diagnosis of NLP, which benefits the non-invasive discrimination of nail conditions and can avoid the potential permanent scars derived from nail biopsies. Furthermore, ultrasound may be a powerful tool to monitor this disease's treatment.

Integrating vascularity into the pattern classification of pilomatricomas on ultrasound provides a more competent approach for discriminative evaluation

BACKGROUND

Pilomatricoma has various manifestations on color Doppler ultrasound, and a differential diagnosis is challenging. The objective of this study was to investigate which characteristics of skin lesions on color Doppler ultrasound are effective in distinguishing pilomatricoma from epidermoid cyst and dermatofibrosarcoma protuberans.

MATERIALS AND METHODS

Records of patients with pilomatricomas (n = 63), epidermoid cysts (n = 76), and dermatofibrosarcoma protuberans (n = 19) who underwent color Doppler ultrasound evaluation and surgical excision were reviewed. The anatomical distribution and color Doppler ultrasound characteristics of these lesions were analyzed. The 63 pilomatricomas were categorized into five types based on their color Doppler ultrasound characteristics, and the roles of these five types in the differential diagnosis of the aforementioned diseases were studied.

RESULTS

Pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans exhibited some similar characteristics. Dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity were the major characteristics of pilomatricomas. The pilomatricomas could be categorized into five types, with type II having a diagnostic performance of sensitivity of 65.08%, specificity of 98.95%, area under the receiver operating characteristic curve (AUC) of 0.743, positive predictive value of 97.62%, and negative predictive value of 81.03% for the diagnosis of the aforementioned skin diseases.

CONCLUSION

A combination of dominantly markedly hyperechoic or hyperechoic appearance, posterior acoustic shadowing, and the presence of vascularity exhibits higher diagnostic performance for the differential diagnosis of pilomatricomas, epidermoid cysts, and dermatofibrosarcoma protuberans.

Assessment of the Diagnostic Performance of Clinical Examinations and High-Frequency Ultrasound in Patients With Pigmented Skin Tumors

OBJECTIVES

To investigate whether the integration of high-frequency ultrasound (HFUS) to routine clinical examinations could improve diagnostic performance and management decision for pigmented skin tumors.

METHODS

Three general practitioners trained previously and a dermatologist independently assessed pigmented skin tumors and rendered management decision based on clinical examinations alone or clinical examinations integrating HFUS.

RESULTS

After integrating HFUS, the diagnostic area under the curve (AUC) (0.658-0.693 versus 0.848, all P < .05) and specificity (46.6-58.6% versus 89.7%, all P < .05) for pigmented skin malignancies were improved for general practitioners, meanwhile unnecessary biopsy rate reduced (42.9-53.6% versus 10.7%, P < .001). To the dermatologist, the diagnostic AUC (0.822 versus 0.949, P < .001), sensitivity (81.7% versus 96.7%, P = .012) and specificity (0.828 versus 0.931, P = .031) improved significantly, meanwhile both missed biopsy rate (14.5% versus 4.8%, P = .031) and unnecessary biopsy rate (19.6% versus 7.1%, P = .016) decreased. Additionally, the diagnostic performance of the general practitioner with integrating HFUS could be comparable with the dermatologist based on clinical examinations alone (all P > .05).

CONCLUSIONS

As a complementary tool of clinical examinations, HFUS could help physicians differentiate pigmented skin malignancies and manage decision.

Ultrasound Features of Onychopapilloma at High-Frequency and Ultra-High Frequency

OBJECTIVE

This study aimed to identify the sonographic features of pathologically confirmed onychopapilloma cases.

METHODS

High-frequency up to 24 MHz and ultra-high frequency-ultrasound up to 71 MHz examinations were performed and correlated with their clinical and pathologic presentations.

RESULTS

Twenty-two cases met the criteria. Clinical presentations revealed longitudinal erythronychia in 63.3% of cases. The ultrasound examinations identified a hypoechoic band in the nail bed (86.3%), nail plate abnormalities including upward displacement (68.2%) and thickening (68.1%), focal hyperechoic focal spots on the nail plate (50%) and irregularities of the ventral plate (33.3%). Color Doppler imaging showed no hypervascularity of the nail bed in all studies. These findings correlate with histological characteristics of onychopapilloma, including nail bed acanthosis, papillomatosis, and layered hyperkeratosis. Recurrence occurred in two cases after surgery, with tumors showing proximal extension in the matrix region on ultrasound not evident during clinical examination.

CONCLUSION

High-frequency and ultra-high-frequency can provide anatomical information in onychopapilloma that could enhance understanding and management.

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.

From Histopathology to High-Resolution Ultrasound Imaging of Skin Scars

Nowadays, modern ultrasound machines and high-frequency transducers allow us to accurately assess the superficial soft tissues of the human body. In this sense, sonographic evaluation of the skin and related pathologies is progressively growing in the pertinent literature. To the best of our knowledge, a standardized sonographic protocol focused on the assessment of pathological skin scars is still lacking. As such, the main purpose of the present study was to propose a technical guide to sonographically assess skin scars in the daily practice of clinicians-starting from knowledge on their histopathological features. In order to standardize the ultrasound examination, a superficial-to-deep, layer-by-layer approach has been proposed to optimize its reproducibility and to promote a common language among the different healthcare providers.

High-Frequency Ultrasound Imaging to Distinguish High-Risk and Low-Risk Dermatofibromas

BACKGROUND

Dermatofibroma has various pathological classifications, some of which pose a risk of recurrence and metastasis. Distinguishing these high-risk dermatofibromas based on appearance alone can be challenging. Therefore, high-frequency ultrasound may provide additional internal information on these lesions, helping to identify high-risk and low-risk dermatofibroma early.

METHODS

In this retrospective study, 50 lesions were analyzed to explore the correlation between clinical and high-frequency ultrasound features and dermatofibroma risk level. Based on their pathological features, the lesions were divided into high-risk (n = 17) and low-risk (n = 33) groups. Subsequently, an identification model based on significant high-frequency ultrasound features was developed.

RESULTS

Significant differences were observed in the thickness, shape, internal echogenicity, stratum basal, and Doppler vascular patterns between the high-risk and low-risk groups. The median lesion thickness for the high-risk dermatofibroma group was 4.1 mm (IQR: 3.2-6.1 mm), while it was 3.1 mm (IQR: 1.3-4.2 mm) for the low-risk dermatofibroma group. In the high-risk dermatofibroma group, irregular morphology was predominant (70.6%, 12/17), the most common being dermis-to-subcutaneous soft tissue penetration (64.7%, 11/17), and heterogenous internal echogenicity was observed in the majority of cases (76.5%, 13/17). On the other hand, regular morphology was more prevalent in the low-risk dermatofibroma group (78.8%, 26/33), primarily limited to the dermis layer (78.8%, 26/33), with homogeneous internal echogenicity also being prevalent in the majority of cases (81.8%, 27/33). Regarding the Doppler vascularity pattern, 69.7% (23/33) of low-risk dermatofibromas had no blood flow, while 64.7% (11/17) of high-risk dermatofibromas had blood flow.

CONCLUSION

High-frequency ultrasound is crucial in distinguishing high-risk and low-risk dermatofibromas, making it invaluable for clinical management.

High-frequency ultrasound in anti-aging skin therapy monitoring

Over the last few decades, high-frequency ultrasound has found multiple applications in various diagnostic fields. The fast development of this imaging technique opens up new diagnostic paths in dermatology, allergology, cosmetology, and aesthetic medicine. In this paper, being the first in this area, we discuss the usability of HFUS in anti-aging skin therapy assessment. The fully automated algorithm combining high-quality image selection and entry echo layer segmentation steps followed by the dermal parameters estimation enables qualitative and quantitative evaluation of the effectiveness of anti-aging products. Considering the parameters of subcutaneous layers, the proposed framework provides a reliable tool for TCA-peel therapy assessment; however, it can be successfully applied to other skin-condition-related problems. In this randomized controlled clinical trial, forty-six postmenopausal women were randomly assigned to the experimental and control groups. Women were treated four times at one-week intervals and applied skin cream daily between visits. The three month follow-up study enables measurement of the long-term effect of the therapy. According to the results, the TCA-based therapy increased epidermal (entry echo layer) thickness, indicating that the thinning process has slowed down and the skin's condition has improved. An interesting outcome is the obtained growth in the intensity of the upper dermis in the experimental group, which might suggest a reduced photo-aging effect of TCA-peel and increased water content. The same conclusions connected with the anti-aging effect of TCA-peel can be drawn by observing the parameters describing the contribution of low and medium-intensity pixels in the upper dermis. The decreased share of low-intensity pixels and increased share of medium-intensity pixels in the upper dermis suggest a significant increase in local protein synthesis.

Ultrasound Assessment of Skin Tumors Local Recurrence

Skin cancer may recur at or around the surgical site despite wide excisions. Prompt clinical and sonographic detection of local recurrence is important since subjects with relapsing melanomas or nonmelanoma malignancies can be managed efficaciously, with a relevant impact on morbidity and survival. Ultrasound is being employed with increasing frequency in the assessment of skin tumors, but most of the published articles relate to initial pretherapeutic diagnosis and staging. This review aims to offer an illustrated guide to the sonographic evaluation of locally recurring skin cancer. We introduce the topic, then we provide some sonographic tips for patient follow-up, then we describe the ultrasound findings in case of local recurrence, illustrating the main mimickers, and finally, we mention the role of ultrasound in guiding diagnostic and therapeutic percutaneous procedures.

Keratinized mucosa width assessment at implant sites using high-frequency ultrasonography

BACKGROUND

The aim of this study was to describe the application of high-frequency ultrasonography (HFUS) for assessing keratinized mucosa (KM) width at implant sites.

METHODS

KM width was measured at 28 implant sites exhibiting a peri-implant soft tissue dehiscence at baseline and 12 months after soft tissue augmentation. KM width assessment was performed with a periodontal probe [clinical assessment (clKM)] and with HFUS, based on the echointensity of the keratinized epithelium compared to the adjacent structures. KM width measurements on ultrasound scans were performed linearly (lnKM) and along the soft tissue profile [surface distance (sdKM)].

RESULTS

No statistically significant differences were observed between clKM, lnKM, and sdKM at baseline, while at 12 months, sdKM (5.313 ± 1.188 mm) was significantly higher than clKM (3.98 ± 1.25 mm) and lnKM (4.068 ± 1.197 mm) (P < 0.001 for both comparisons). A linear relationship between mucosal thickness (MT) and the difference between sdKM and lnKM was observed. In 95.2% of cases with MT > 2.51 mm, the discrepancy between sdKM and lnKM was at least 1 mm.

CONCLUSIONS

HFUS is a noninvasive and valuable tool for measure KM width at implant site. Evaluating KM width along the soft tissue profile as a surface distance may improve the accuracy of the assessment.

Ultrasonographic Assessment of Depth Infiltration in Melanoma and Non-melanoma Skin Cancer

The preoperative assessment of infiltration depth in melanoma and non-melanoma skin cancer by means of high-frequency ultrasound (≥18 MhZ) is essential for optimizing the therapeutic approach in our patients. Often, histologically confirmed skin tumors are directly referred to surgical departments for resection, and sonography is increasingly helping us identify those subjects who are no longer candidates for extensive surgical interventions. In cases of deep tumor infiltration, with potential surgical failure e.g. impairment of the quality of life and significant esthetic and functional complications, preoperative sonography can guide the surgeon to withstand from an operation and decide instead in favor of less mutilating radiooncological or medical treatment options. Furthermore, in melanoma patients, the preoperative knowledge of the tumor depth is essential for the determination of the therapeutic approach, the correct safety margins and the need of a sentinelnode biopsy. We herein encourage the use of preoperative sonography in dermatologic surgery whenever possible as it represents an easy, painless, "in vivo" method, which provides clinicians with significant clinical information that can influence the therapy and improve patient compliance.

Clinical, dermoscopic, and ultrasonic monitoring of the response to biologic treatment in patients with moderate-to-severe plaque psoriasis

Background

Assessment of therapeutic response of psoriasis has relied traditionally on clinical observation, and effective non-invasive tools are desirable.

Objectives

To investigate the value of dermoscopy and high-frequency ultrasound (HFUS) in the monitoring of psoriatic lesions treated with biologics.

Methods

Patients with moderate-to-severe plaque psoriasis treated with biologics were evaluated by clinical, dermoscopic, and ultrasonic scores at weeks 0, 4, 8, and 12. Clinical scores, including Psoriasis Area Severity Index (PASI) and target lesion score (TLS), were evaluated at representative lesions. Dermoscopy was performed to assess the red background, vessels, and scales on a 4-point scale as well as the presence of hyperpigmentation, hemorrhagic spots, and linear vessels. HFUS was performed to measure the thicknesses of the superficial hyperechoic band and subepidermal hypoechoic band (SLEB). The correlation between clinical, dermoscopic, and ultrasonic evaluation was also analyzed.

Results

In total, 24 patients were analyzed and achieved 85.3 and 87.5% reduction of PASI and TLS, respectively, after 12 weeks of treatment. The red background, vessels, and scales scores under dermoscopy were reduced by 78.5, 84.1, and 86.5%, respectively. Some patients developed hyperpigmentation and linear vessels after treatment. Hemorrhagic dots slowly subside over the therapeutic course. Ultrasonic scores were significantly improved with an average reduction of 53.9% in superficial hyperechoic band thickness and 89.9% in SLEB thickness. TLS in the clinical variables, scales in dermoscopic variables, and SLEB in ultrasonic variables decreased the most significantly in the early stage of treatment (week 4) with 55.4, 57.7, and 59.1% (P > 0.05), respectively. Most of the variables, including the red background, vessels, scales, and SLEB thickness, were strongly correlated with TLS. High correlations were also found between the SLEB thickness and the red background or vessels scores, and between the superficial hyperechoic band thickness and the scales scores.

Conclusion

Both dermoscopy and HFUS were useful in the therapeutic monitoring of moderate-to-severe plaque psoriasis.

Key Points to Select a Device for Dermatologic Ultrasound

What points to consider when selecting a device for practicing dermatologic ultrasound is an excellent question. After we met the requisites published in the guidelines for practicing dermatologic ultrasound, it is necessary to consider the main objective of the use because it is not the same to be focused mostly on the avoidance of the puncture of important facial vessels such as the case of injectors of cosmetic fillers in comparison to the use of operators that need to deal with the diagnosis and monitoring of a wide range of dermatologic pathologies. Currently, a broad variety of ultrasound devices meets the minimum requirements for practicing these examinations in the market. Thus, small, portable, and high-end devices may present advantages and limitations that must be balanced according to the primary purposes and the budget. Moreover, the shape and footprint of the probes can make difficult or facilitate a dermatologic procedure. Other points to consider are the type of storage and the need for technical service. In summary, there are key points that we need to consider when we select a dermatologic ultrasound device in dermatology or aesthetics.

Key Points to Select a Device for Dermatologic Ultrasound

What points to consider when selecting a device for practicing dermatologic ultrasound is an excellent question. After we met the requisites published in the guidelines for practicing dermatologic ultrasound, it is necessary to consider the main objective of the use because it is not the same to be focused mostly on the avoidance of the puncture of important facial vessels such as the case of injectors of cosmetic fillers in comparison to the use of operators that need to deal with the diagnosis and monitoring of a wide range of dermatologic pathologies. Currently, a broad variety of ultrasound devices meets the minimum requirements for practicing these examinations in the market. Thus, small, portable, and high-end devices may present advantages and limitations that must be balanced according to the primary purposes and the budget. Moreover, the shape and footprint of the probes can make difficult or facilitate a dermatologic procedure. Other points to consider are the type of storage and the need for technical service. In summary, there are key points that we need to consider when we select a dermatologic ultrasound device in dermatology or aesthetics.

Clinical and Sonographic Classification of Neurofibromas in Children with Neurofibromatosis Type 1 - A Cluster Analysis

PURPOSE

 High-frequency ultrasound allows the accurate identification of neurofibromas in neurofibromatosis type 1 (NF1). This study aimed to analyze the ultrasound features of neurofibromas in children with NF1, to establish a classification based on the clinical and sonographic patterns of the different types of neurofibromas, and to evaluate the interobserver correlation coefficient (κ) of this classification.

MATERIALS AND METHODS

 In this prospective, single referral center observational study, clinical and ultrasound findings of neurofibromas in children diagnosed with NF 1 were analyzed. To identify the ultrasound patterns, a cluster analysis allowing the inclusion of both clinical and ultrasound data was designed. The κ coefficient was calculated using 9 external evaluators.

RESULTS

 265 ultrasound scans were performed on a total of 242 neurofibromas from 108 children diagnosed with NF1. Cluster analysis allowed the identification of 9 patterns (Snedecor's F, P < 0.001) classified as "classic" cutaneous neurofibroma, blue-red neurofibroma, pseudoatrophic neurofibroma, nodular subcutaneous neurofibroma, diffuse subcutaneous neurofibroma, congenital cutaneous neurofibroma, congenital plexiform neurofibroma, congenital diffuse and plexiform neurofibroma, and subfascial neurofibroma. The κ coefficient of the interobserver ratings was 0.82.

CONCLUSION

 Patterns identified in the cluster analysis allow neurofibromas to be classified with a very high interobserver correlation.

Dynamic ultrasound evaluation of body fillers and biostimulators in the buttocks of fresh-frozen specimen

BACKGROUND

Ultrasound imaging is a useful tool to study the injection of fillers and biostimulators in the body.

OBJECTIVE

Sonographically evaluate real-time injections of fillers and biostimulators and describe their behavior in the subcutaneous tissue of the buttocks of fresh-frozen specimen.

METHODS

injection of two brands of high-density hyaluronic acid (HA), one brand of calcium hydroxyapatite (CaHA), one brand of hybrid injectable (CaHa + HA), one brand of polycaprolactone (PCL) and three brands of poly-l-lactic acid (PLLA) were performed in the subcutaneous tissue of the gluteal region under ultrasonography visualization on a fresh-frozen specimen. Videos during injection and static images immediately after injection were obtained. The sonographic aspects of the substances and their dispersion and interaction with the surrounding tissues were described.

RESULTS

Real-time ultrasound showed different dispersion patterns of the two brands of HA, CaHA, hybrid injectable (CaHa + HA) and the three brands of PLLA. The sonographic aspects among the brands of PLLA were also different.

CONCLUSIONS

The dynamic ultrasound evaluation of the injection of HA, CaHA, hybrid injectable (CaHa + HA), PCL and PLLA in a fresh-frozen specimen shed some light on their aspects and dispersion pattern in the buttock. If these patterns are confirmed in further studies in vivo, there will be a positive impact on the selection and development of safer and more effective techniques to enhance buttock contour.

From physical to ultrasound examination in lymphedema: a novel dynamic approach

In daily practice, medical history and physical examination are commonly coupled with anthropometric measurements for the diagnosis and management of patients with lymphatic diseases. Herein, considering the current progress of ultrasound imaging in accurately assessing the superficial soft tissues of the human body; it is noteworthy that ultrasound examination has the potential to augment the diagnostic process. In this sense/report, briefly revisiting the most common clinical maneuvers described in the pertinent literature, the authors try to match them with possible (static and dynamic) sonographic assessment techniques to exemplify/propose an 'ultrasound-guided' physical examination for different tissues in the evaluation of lymphedema.

Role of shear wave elastography ultrasound in patients with systemic sclerosis

PURPOSE

A study of shear wave elastography (SWE) for evaluation of skin stiffness in systemic sclerosis (SSc) patients. The purpose of this study was to measure the skin stiffness and thickness in patients with scleroderma using shear wave elastography.

METHODS

Prospective data collections of skin stiffness and thickness using SWE in SSc and control groups.

RESULTS

Skin stiffness and thickness were done in 29 patients with SSc and a 29 control population using SWE on bilateral forearms. The SSc patients had thicker skin and higher stiffnesses than the control group. The mean of skin thickness and stiffness using SWE of SSc are 1.74 mm and 47.32 kPa while normal subjects were 1.5 mm and 19.5 kPa. Mean differences were 0.023 mm (95% CI 0.15-0.3, p < 0.001) and 27.82 kPa (95% CI 22.63-33.01, p < 0.001). The dorsal forearms tend to have a higher SWE than the volar forearms in SSc. No statistically significant differences between gender, age or dominancy of skin stiffness were found. SWE has a good correlation with clinical manual palpation of forearms (mRSS) with Spearman rho's of 0.550 (p = 0.002) and 0.508 (p = 0.005) of dominant and non-dominant forearms.

CONCLUSION

The application of SWE can be used for evaluation of skin involvement in scleroderma patients with good correlations with the mRSS that was used in the current patients. Furthermore, SWE is a safe technique for either diagnosis or follow up.

Updated Role of High-frequency Ultrasound in Assessing Dermatological Manifestations in Autoimmune Skin Diseases

Autoimmune skin diseases are a group of disorders that arise due to the dysregulated immune system attacking self-antigens, causing multiple tissue and organ lesions. With disease progression, the physical and psychological health of patients may be seriously damaged. High-frequency ultrasound is non-invasive, reproducible, and suitable for visualizing the fine structure of external organs. The usage of high-frequency ultrasound has increased in recent years in the auxiliary diagnosis and monitoring of various skin diseases; it serves as a promising tool for dermatological disease assessment. This review summarizes the characteristics of high-frequency ultrasound imaging in common autoimmune skin diseases, including systemic lupus erythematosus, scleroderma, psoriasis, dermatomyositis, and pemphigus/pemphigoid. The objective of this review is to provide new ideas and strategies for dermatologists to diagnose and track the prognosis of autoimmune skin diseases.

Skin sonography in children: a review

Skin lesions are not uncommon in children, and most of them are benign. However, they can be a matter of concern. Although in most cases the diagnosis can be suspected based on clinical history and physical examination, in some cases clinical findings are nonspecific. High-frequency color Doppler US is a noninvasive technique that can play a relevant role in these cases and give important anatomical information for final clinical management. US can be helpful to avoid unnecessary surgery, plan a surgical excision and avoid advanced imaging studies such as MRI and CT, which have a lower resolution for the skin. Different lesions can look similar on US, and clinical correlation is always important. The purpose of this article is to show a variety of skin lesions that occur in children, emphasizing clinical-sonographic correlation, and to familiarize pediatric radiologists with the US technique and sonographic appearance of common skin lesions in children.

Sun Sign in the Ultrasound Diagnosis and Activity Assessment of Morphea

Morphea, a localized form of scleroderma, is a chronic inflammatory autoimmune disease of the skin. Color Doppler Ultrasound has been reported as a reliable tool to assess the activity of the disease. With histologically confirmed cases, this case series describes a new ultrasound sign consisting of a hyperechoic halo surrounding superficial subcutaneous veins of the extremities in transverse view, named the sun sign. This sign can help diagnose morphea in the inflammatory phase and correlate in pathology with perivascular infiltrates surrounding superficial subcutaneous veins.

[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.

Repeated ultrasound-guided percutaneous thermal ablation combined with systemic therapy achieves a stable condition in an end-stage patient with more than 10 liver metastases from breast cancer: The importance of sonazoid assisted contrast-enhanced ultrasound and fusion imaging

The liver is one of the most frequent metastatic sites of breast cancer with a relatively poor prognosis. Systemic chemotherapy is an effective treatment but the efficacy is different between the subtypes of breast cancer. Percutaneous thermal ablation is considered to be a minimally invasive and effective local treatment for breast cancer liver metastases (BCLM). This case report described a patient with BCLM who adopted a strategy of systemic chemotherapy and repeated ultrasound (US) -guided percutaneous thermal ablation procedures. The survival time already reached 8 years till now with the metastases well-controlled and acceptable life quality was achieved.

Ultrasonography in dermatologic surgery: revealing the unseen for improved surgical planning

Ultrasonography (US) is a modern, in vivo imaging method, which is increasingly being used in dermatology as a complementary tool to clinical examination and dermoscopy. At higher frequencies (15 MHz and above), US is an established method for assessing benign and malignant skin lesions, locoregional staging, monitoring the therapeutic efficacy in various inflammatory skin conditions, and patient follow-up. One field, which may increasingly benefit from performant imaging techniques such as US is dermatologic surgery. Preoperative imaging of cutaneous tumors, inflammatory skin conditions (hidradenitis suppurativa, abscesses, etc.), or nail pathology provide dermatologic surgeons with relevant information for an optimal surgical planning, identifying potential complex aspects which might require interdisciplinary approaches, herein sparing unnecessary surgical interventions and increasing patients' compliance. In this review, we discuss the increasing significance of US in the field of dermatologic surgery, as well as the spectrum of cutaneous pathology where sonography can aid in the preoperative setting to provide a more precise, individualized surgical planning for better counseling to our patients and improved surgical results.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part I: Extraarticular Pathologies

The first part of the guidelines and recommendations for musculoskeletal ultrasound, produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), provides information about the use of musculoskeletal ultrasound for assessing extraarticular structures (muscles, tendons, entheses, ligaments, bones, bursae, fasciae, nerves, skin, subcutaneous tissues, and nails) and their pathologies. Clinical applications, practical points, limitations, and artifacts are described and discussed for every structure. After an extensive literature review, the recommendations have been developed according to the Oxford Centre for Evidence-based Medicine and GRADE criteria and the consensus level was established through a Delphi process. The document is intended to guide clinical users in their daily practice.

Preliminary Clinical Experience with a Novel Optical–Ultrasound Imaging Device on Various Skin Lesions

A compact handheld skin ultrasound imaging device has been developed that uses co-registered optical and ultrasound imaging to provide diagnostic information about the full skin depth. The aim of the current work is to present the preliminary clinical results of this device. Using additional photographic, dermoscopic and ultrasonic images as reference, the images from the device were assessed in terms of the detectability of the main skin layer boundaries and characteristic image features. Combined optical-ultrasonic recordings of various types of skin lesions (melanoma, basal cell carcinoma, seborrheic keratosis, dermatofibroma, naevus, dermatitis and psoriasis) were taken with the device (N = 53) and compared with images captured with a reference portable skin ultrasound imager. The investigator and two additional independent experts performed the evaluation. The detectability of skin structures was over 90% for the epidermis, the dermis and the lesions. The morphological and echogenicity information observed for the different skin lesions were found consistent with those of the reference ultrasound device and relevant ultrasound images in the literature. The presented device was able to obtain simultaneous in-vivo optical and ultrasound images of various skin lesions. This has the potential for further investigations, including the preoperative planning of skin cancer treatment.

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.

High-frequency ultrasound in the diagnosis of the spectrum of cutaneous squamous cell carcinoma: Noninvasively distinguishing actinic keratosis, Bowen's Disease, and invasive squamous cell carcinoma

OBJECTIVE

To evaluate high-frequency ultrasound (HFUS) features for diagnosing cutaneous squamous cell carcinoma (cSCC) as a spectrum of progressively advanced malignancies, including precursor actinic keratosis (AK), Bowen's disease (BD), and invasive squamous cell carcinoma (iSCC).

METHOD

In this retrospective study, 160 skin lesions diagnosed histopathologically (54 AK, 54 BD, and 52 iSCC) in 160 patients were included. The HFUS features of AK, BD, and iSCC were analyzed. The obtained data were evaluated using univariate and forward multivariate logistic regression analyses.

RESULTS

The most significant HFUS features in AK were regular surface (odds ratio [OR], 8.42) and irregular basal border (OR, 6.36). The most significant HFUS features in BD were crumpled surface (OR, 19.62) and layer involvement confined to the epidermis (OR, 3.96). The most significant HFUS features in iSCC were concave surface (OR, 27.06), stratum corneum (SC) detachment (OR, 14.41), irregular basal border (OR, 4.01), and convex surface (OR, 3.73). The characteristics of surface features, basal border, and layer involvement could be valuable HFUS clues in the discrimination of AK, BD, and iSCC.

CONCLUSION

High-frequency ultrasound is valuable for the differentiation of AK, BD, and iSCC, which may allow dynamic and noninvasive monitoring in the spectrum of cSCC.

High-frequency ultrasound in the 21st century

The beginnings of skin ultrasound date back to about 50 years ago. However, the dynamic progress of skin ultrasound took place in the last twenty years, when the unprecedented development of computer technologies occurred, which resulted in the popularization of and easier access to modern ultrasound equipment. Skin tests can be performed with both classic scanners equipped with broadband transducers with a minimum frequency of 15 MHz, and specially dedicated skin systems with high-frequency scanners, which are equipped with mechanical transducers with a frequency of 20 MHz to up to 100 MHz. Owing to technologically advanced machines, ultrasonography has proved to be useful in many areas. The aim of this study was to present the current knowledge and possibilities of skin imaging using high-frequency ultrasonography. Te paper discusses technical aspects, types of devices available on the market, as well as methods for the analysis of ultrasound skin images and parameters useful in their interpretation. We also present current applications of skin ultrasound, with particular emphasis on dermatology and aesthetic medicine. In the field of dermatology, we discussed imaging of focal lesions as well as an assessment of pathologically changed skin and treatment monitoring. We also focused on the use of high-frequency ultrasonography in aesthetic medicine and cosmetology. The popularity of this method is constantly growing in these fields, and ultrasound is now used in everyday practice to assess the skin, plan and monitor procedures, as well as to treat potential complications. High-frequency ultrasonography is a highly effective method for skin evaluation, although still underappreciated in may fields. Further research is needed to standardize this modality, as well as to implement training for operators, and to popularize this imaging technique.