Quantified ultrasound elastography in the assessment of cutaneous carcinoma

Review of Non-Invasive Imaging Technologies for Cutaneous Melanoma

Imaging technologies are constantly being developed to improve not only melanoma diagnosis, but also staging, treatment planning, and disease progression. We start with a description of how melanoma is characterized using histology, and then continue by discussing nearly two dozen different technologies, including systems currently used in medical practice and those in development. For each technology, we describe its method of operation, how it is or would be projected to be most commonly used in diagnosing and managing melanoma, and for systems in current use, we identify at least one current manufacturer. We also provide a table including the biomarkers identified by and main limitations associated with each technology and conclude by offering suggestions on specific characteristics that might best enhance a technology's potential for widespread clinical adoption.

Asynchronous, semi-reverberant elastography

Optical coherence elastography measures elasticity-a property correlated with pathologies such as tumors due to fibrosis, atherosclerosis due to heterogeneous plaque composition, and ocular diseases such as keratoconus and glaucoma. Wave-based elastography, including reverberant elastography, leverages the properties of shear waves traveling through tissue primarily to infer shear modulus. These methods have already seen significant development over the past decade. However, existing implementations in OCT require robust synchronization of shear wave excitation with imaging, complicating widespread clinical adoption. We present a method for complete recovery of the harmonic shear wave field in an asynchronous, conventional frame-rate, raster-scanning OCT system by modeling raster-scanning as an amplitude modulation of the displacement field. This technique recovers the entire spatially and temporally coherent complex valued shear wave field from just two B-scans, while reducing the time scale for sensitivity to motion from minutes to tens of milliseconds. To the best of our knowledge, this work represents the first successful demonstration of reverberant elastography on a human subject in vivo with a conventional frame-rate, raster-scanning OCT system, greatly expanding opportunity for widespread translation.

Diagnostic accuracy of high-frequency ultrasound for cutaneous neoplasms: a narrative review of the literature

High-frequency ultrasound has been used to visualize depth and vascularization of cutaneous neoplasms, but little has been synthesized as a review for a robust level of evidence about the diagnostic accuracy of high-frequency ultrasound in dermatology. A narrative review of the PubMed database was performed to establish the correlation between ultrasound findings and histopathologic/dermoscopic findings for cutaneous neoplasms. Articles were divided into the following four categories: melanocytic, keratinocytic/epidermal, appendageal, and soft tissue/neural neoplasms. Review of the literature revealed that ultrasound findings and histopathology findings were strongly correlated regarding the depth of a cutaneous neoplasm. Morphological characteristics were correlated primarily in soft tissue/neural neoplasms. Overall, there is a paucity of literature on the correlation between high-frequency ultrasound and histopathology of cutaneous neoplasms. Further studies are needed to investigate this correlation in various dermatologic conditions.

Practical approach to ultrasound of soft tissue tumors and the added value of MRI: how I do it

This review outlines a practical approach to the everyday assessment of both non-neoplastic and neoplastic soft tissue tumors, focusing on ultrasound examination, though emphasizing the added benefit of magnetic resonance imaging in certain instances. Ultrasound approach and assessment, practical scenarios, reporting, biopsy, and follow-up are covered, as well as the criteria used to distinguish benign from malignant tumors. The potential benefits and current limitations of elastography and contrast-enhanced ultrasound in assessment are also addressed. Examples of commonly encountered soft tissue tumors are shown. Ultrasound can characterize most soft tissue masses based on their ultrasound appearance alone. Following ultrasound examination, three potential scenarios usually exist in clinical practice: (a) confident regarding diagnosis, (b) indeterminate mass with no evidence of malignancy, and (c) indeterminate mass with possibility of malignancy. A diagnostic pathway for each of these scenarios is provided. Magnetic resonance imaging is generally not helpful in further characterizing masses which are indeterminate on ultrasound assessment, though it is helpful in addressing other issues such as exact tumor location and neurovascular bundle involvement that may not be fully resolved on ultrasound examination. In these situations, magnetic resonance imaging examination can be tailored to address those specific questions that have not been adequately addressed on ultrasound examination. In this sense, both examinations are highly complementary. Tips for undertaking magnetic resonance imaging examinations are provided.

High-Frequency Ultrasound in Diagnosis and Treatment of Non-Melanoma Skin Cancer in the Head and Neck Region

Non-melanoma skin cancer is one of the most frequently diagnosed cancers in the human body and unfortunately the incidence continues to increase. NMSC is represented by the basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs), which are the most prevalent forms, and basosquamous cell carcinomas (BSC) together with Merkel cell carcinoma (MCC), which are rare types but with a very aggressive pattern and poor prognosis. The pathological diagnosis is hard to assess without a biopsy, even by the dermoscopy. Moreover, the staging can be problematic because there is no access clinically to the thickness of the tumor and the depth of the invasion. The aim of this study was to evaluate the role of ultrasonography (US), which is a very efficient imaging method, non-irradiating and cheap, in diagnosis and treatment of non-melanoma skin cancer in the head and neck region. Thirty-one patients with highly suspicious malignant lesions of the head and neck skin were evaluated in the Oral and Maxillo-facial Surgery Department and Imaging Department in Cluj Napoca, Romania. All tumors were measured with three transducers: 13 MHz, 20 MHz and 40 MHz. Doppler examination and elastography were also used. The length, width, diameter, thickness, the presence of necrosis, status of regional lymph nodes, the presence of hyperechoic spots, strain ratio and vascularization were all recorded. After that, all patients were treated by surgical resection of the tumor and reconstruction of the defect. Immediately after surgical resection, all tumors were measured again after the same protocol. The resection margins were evaluated by all three types of transducers in order to detect malignant involvement and the results were compared with the histopathological report. We found that the 13 MHz transducers offered a big picture of the tumor but the level of details, in the form of the presence of the hyperechoic spots, is reduced. We recommend this transducer for evaluation of surgical margins or for the large skin tumors. The 20 and 40 MHz transducers are better for viewing the particularities of malignant lesions and for an accurate measurement; however, in the case of large size lesions, assessing all three dimensions of the tumor can be difficult. The intralesional hyperechoic spots are present in case of BCC and they can be used for differential diagnosis of BCC.

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.

High-frequency ultrasound for differentiation between high-risk basal cell carcinoma and cutaneous squamous cell carcinoma

BACKGROUND

The similar visual appearance of high-risk basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) may cause confusion for diagnosis. High-frequency ultrasound (HFUS) may provide additional intralesional information and thus help to distinguish them.

METHOD

In this retrospective study, we analyzed the clinical characteristics, HFUS grayscale, and color Doppler flow imaging (CDFI) features of pathologically confirmed high-risk BCC and cSCC lesions (n = 65 vs n = 68). Subsequently, discrimination models based on the significant HFUS features were established.

RESULTS

Between high-risk BCC and cSCC lesions, the HFUS grayscale features of the lesion size (10.0 mm vs 17.4 mm), thickness (3.1 mm vs 5.9 mm), internal hyperechoic spots (80.0% vs 23.5%), and posterior acoustic shadowing (16.9% vs 66.2%) were statistically different (all p < 0.001). As for the CDFI features, high-risk BCC lesions mainly appeared as pattern II (47.7%), while cSCC lesions mainly appeared as pattern III (66.2%). Based on the above five features, an optimal discrimination model was established with a sensitivity of 91.2%, a specificity of 87.7%, and an accuracy of 89.5%.

CONCLUSION

HFUS features, including size, thickness, internal hyperechoic spots, posterior acoustic shadowing, and Doppler vascularity pattern, are useful for differential diagnosis between high-risk BCC and cSCC.

Differentiation of benign and malignant superficial soft tissue lesions using real-time strain elastography

Background/aim

To evaluate benign and malignant cutaneous-subcutaneous lesions using real-time strain elastography (RTSE) and to compare the findings with histopathologic results.

Materials and methods

Over a period of 10 months, 72 patients (38 with benign and 34 with malignant cutaneous and subcutaneous lesions) were prospectively included in this study. Elasticity patterns and strain ratios were examined for each lesion. Lesions were evaluated in 4 groups as yellow-red (soft; pattern-1), green-yellow (moderate; pattern-2), blue-green (hard; pattern-3) and blue (hardest; pattern-4). The stiffness of the lesions was displayed with strain ratios by comparing of a nearby reference tissue. The recorded images were compared with histopathologic findings.

Results

On sonoelastograms, considering patterns 1-2 as benign and patterns 3-4 as malignant, the sensitivity, specificity, and positive and negative predictive values for the differentiation of malignant from benign lesions were 100%, 68.5%, 74%, and 100%, respectively. Considering a cut-off value of the strain ratio as > 3.05, the sensitivity, specificity, and positive and negative predictive values were 91%, 89%, 88%, and 92%, respectively. The area under the curve (AUC: 0.972) showed the excellent ability of strain elastography to differentiate benign and malignant lesions.

Conclusion

RTSE is an important imaging tool to differentiate benign and malignant superficial soft tissue lesions. Our results suggest that RTSE can be used to predict malignancy since malignant lesions are more confidentially diagnosed than benign superficial soft tissue lesions on elastograms.

Is Computer-Assisted Tissue Image Analysis the Future in Minimally Invasive Surgery? A Review on the Current Status of Its Applications

Purpose: Computer-assisted tissue image analysis (CATIA) enables an optical biopsy of human tissue during minimally invasive surgery and endoscopy. Thus far, it has been implemented in gastrointestinal, endometrial, and dermatologic examinations that use computational analysis and image texture feature systems. We review and evaluate the impact of in vivo optical biopsies performed by tissue image analysis on the surgeon’s diagnostic ability and sampling precision and investigate how operation complications could be minimized. Methods: We performed a literature search in PubMed, IEEE, Xplore, Elsevier, and Google Scholar, which yielded 28 relevant articles. Our literature review summarizes the available data on CATIA of human tissues and explores the possibilities of computer-assisted early disease diagnoses, including cancer. Results: Hysteroscopic image texture analysis of the endometrium successfully distinguished benign from malignant conditions up to 91% of the time. In dermatologic studies, the accuracy of distinguishing nevi melanoma from benign disease fluctuated from 73% to 81%. Skin biopsies of basal cell carcinoma and melanoma exhibited an accuracy of 92.4%, sensitivity of 99.1%, and specificity of 93.3% and distinguished nonmelanoma and normal lesions from benign precancerous lesions with 91.9% and 82.8% accuracy, respectively. Gastrointestinal and endometrial examinations are still at the experimental phase. Conclusions: CATIA is a promising application for distinguishing normal from abnormal tissues during endoscopic procedures and minimally invasive surgeries. However, the efficacy of computer-assisted diagnostics in distinguishing benign from malignant states is still not well documented. Prospective and randomized studies are needed before CATIA is implemented in clinical practice.

Characterization of the Biomechanical Properties of Skin Using Vibrational Optical Coherence Tomography: Do Changes in the Biomechanical Properties of Skin Stroma Reflect Structural Changes in the Extracellular Matrix of Cancerous Lesions?

Early detection of skin cancer is of critical importance since the five-year survival rate for early detected skin malignancies is 99% but drops to 27% for cancer that has spread to distant lymph nodes and other organs. Over 2.5 million benign skin biopsies (55% of the total) are performed each year in the US at an alarming cost of USD ~2.5 B. Therefore there is an unmet need for novel non-invasive diagnostic approaches to better differentiate between cancerous and non-cancerous lesions, especially in cases when there is a legitimate doubt that a biopsy may be required. The purpose of this study is to determine whether the differences in the extracellular matrices among normal skin, actinic keratosis (AK), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) can be assessed non-invasively using vibrational optical coherence tomography (VOCT). VOCT is a new diagnostic technology that uses infrared light and audible sound applied transversely to tissue to measure the resonant frequencies and elastic moduli of cells, dermal collagen, blood vessels and fibrous tissue in skin and lesion stroma without physically touching the skin. Our results indicate that the cellular, vascular and fibrotic resonant frequency peaks are altered in AK, BCC and SCC compared to those peaks observed in normal skin and can serve as physical biomarkers defining the differences between benign and cancerous skin lesions. The resonant frequency is increased from a value of 50 Hz in normal skin to a value of about 80 Hz in pre- and cancerous lesions. A new vascular peak is seen at 130 Hz in cancerous lesions that may reflect the formation of new tumor blood vessels. The peak at 260 Hz is similar to that seen in the skin of a subject with Scleroderma and skin wounds that have healed. The peak at 260 Hz appears to be associated with the deposition of large amounts of stiff fibrous collagen in the stroma surrounding cancerous lesions. Based on the results of this pilot study, VOCT can be used to non-invasively identify physical biomarkers that can help differentiate between benign and cancerous skin lesions. The appearance of new stiff cellular, fragile new vessels, and stiff fibrous material based on resonant frequency peaks and changes in the extracellular matrix can be used as a fingerprint of pre- and cancerous skin lesions.

Strain elastography for the assessment of skin nodules in dogs

BACKGROUND

Strain elastography (SE) is a modern imaging technology that provides an additional way of evaluating the changes in soft tissue elasticity caused by pathophysiological processes. Despite its widespread use in human medicine, only a few studies on the application of SE in veterinary medicine are available.

OBJECTIVES

To evaluate the potential usefulness of SE as an integrative imaging model in the standard ultrasound technique to better discriminate between inflammatory and neoplastic skin nodules in dogs.

ANIMALS

Fifty-one client-owned dogs with clinical evidence of single or multiple skin nodules detected during routine dermatological examination.

METHODS AND MATERIALS

Margins, echogenicity, echo-structure, calcification and vascularisation of 65 skin nodules were assessed with ultrasound, and SE was used to score qualitative (E-score, E-index, E2) and semiquantitative (SR) parameters. A comparison of diagnostic yields with cytological and histological findings as the gold standard was performed.

RESULTS

Mast cell and benign follicular tumours showed the highest E-scores and SRs among neoplastic nodules; statistically significant differences were not detected. Calcific and nonvascularised nodules showed significantly higher E-index values than the others. Overall, a negative correlation was observed between the longitudinal diameter of skin nodules and the qualitative elastic parameters.

CONCLUSIONS AND CLINICAL IMPORTANCE

In this study, SE proved to be useful to identify only a subset of nodules such as mast cells and hair follicular tumours. Although evidence supporting the use of SE in evaluating skin nodules was demonstrated to below, indicators to guide further research were developed.

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

Dermatologic ultrasound is a recent application of ultrasound for the evaluation of healthy skin and appendages and their diseases. Although the scientific literature regarding this application is still not sufficient for evidence-based guidelines, general recommendations issued by scientific societies are necessary. The EFSUMB (European Federation of Societies for Ultrasound in Medicine and Biology) steering committee for dermatologic ultrasound has developed a series of consensus position statements regarding the main fields of dermatologic ultrasound (technical requirement, normal skin and appendages, inflammatory skin diseases, tumoral skin diseases, aesthetic dermatology and practice-training requirements). This document is the foundation for future evidence-based recommendations and guidelines for dermatologic ultrasound practice.

[Histological verification of autofluorescence borders of periorbital skin tumors]

Tumor borders are one of the most significant characteristics of any tumor, including that of the skin.

PURPOSE

To compare histological borders of periorbital skin tumors with their autofluorescence borders built from the analysis of non-induced protoporphyrin IX autofluorescence.

MATERIAL AND METHODS

The study group included 8 patients with skin tumors of the eyelids, periorbital region, eyebrow and zygomatic regions aged 54-88 years. The tumors varied in size from 2 to 8 mm and all displayed signs of basal cell carcinoma (BCC). At admission, all the patients underwent non-induced autofluorescence diagnosis. The images were processed with the «CancerPlot» program. During radio excision, the autofluorescent border of each neoplasm was marked with a surgical incision of about 5 mm long and 2 mm deep.

RESULTS

Upon pathomorphological examination, solid BCC was identified in 7 cases. The remaining case was senile keratosis. All reference incisions were located in healthy tissues not farther than 1 mm from the tumor (or keratosis locus, correspondingly).

CONCLUSION

By the example of facial BCC, an evident correlation was established between histological borders of the tumor and its native (non-induced) protoporphyrin IX autofluorescence.

Quantitative assessment of temporal skin elasticity using shear wave elastography in pediatric cochlear implant users

OBJECTIVE

To evaluate temporal skin thicknesses and stiffness values using shear wave elastography (SWE) in asymptomatic pediatric patients who underwent cochlear implantation.

SUBJECTS AND METHODS

Sixty-four deafened pediatric patients with unilateral cochlear implant (CI) who had no complications were enrolled. The age, sex, weight, height, body mass index (BMI), CI side, duration of CI use and CI device brand of all participants were noted. Temporal skin thickness and stiffness values were measured from implanted and contralateral unimplanted sides using SWE.

RESULTS

The mean skin thickness measurements of implanted and unimplanted sides were 11.87 ± 3.42 and 5.34 ± 1.56 mm, respectively. The mean skin stiffness measurements of implanted and unimplanted sides were 3.08 ± 0.7 and 1.29 ± 0.26 m/s, respectively. There were statistically significant differences in skin thickness and stiffness between implanted and unimplanted sides (P < .001, P < .001). The mean skin thickness and stiffness measurements did not differ among types of CI devices (P = .948, P = .362). Age had positive correlation with implanted (P < .001, P = .019) and unimplanted sides (P < .001, P < .001) skin thickness and stiffness. BMI had positive correlation with implanted (P < .001, P = .023) and unimplanted sides (P < .001, P < .001) skin thickness and stiffness. Duration of CI use had positive correlation with implanted side skin thickness (P < .001) and stiffness (P = .031).

CONCLUSION

Temporal skin thickness and stiffness increase after CI surgery. SWE has the potential to improve diagnostic accuracy, and our results may provide important data for evaluation of clinical entities that affect temporal skin structures.

Use of imaging techniques for melanocytic naevi and basal cell carcinoma in integrative analysis (Review)

Early detection of skin cancer is essential in order to obtain an improved prognosis. Clinicians need more objective and non-invasive examination methods to support their decision whether to biopsy or not tumoral lesions. These may include several imaging techniques such as dermoscopy, videodermoscopy, also known as sequential digital dermoscopy (SDD), computer-aided diagnosis (CAD), total body photography, imaging and high-frequency ultrasonography (HFUS), reflectance confocal microscopy, multiphoton tomography, electrical impedance spectroscopy, Raman spectroscopy, stepwise two-photon-laser spectroscopy and quantitative dynamic infrared. This review summarizes the current developments in the field of melanocytic lesions, such as naevi and basal cell carcinoma (BCC) imaging techniques. The aim was to collect and analyze data concerning types, indications, advantages and disadvantages of modern imaging techniques for in vivo skin tumor diagnosis. Two main methods were focused on, namely videodermoscopy and HFUS, which can be included in daily dermatologists' practice. In skin tumors HFUS allows the assessment of tumoral lesions with depth smaller than 1.5 cm, being described a correlation between ultrasonographic depth and the histologic index.

The accuracy of elastographic strain ratio and ultrasound thickness in the differentiation of thin and thick cutaneous melanoma

Background

Cutaneous melanoma is the most deadly of skin neoplasms. Few studies have investigated the role of elastography characteristics so the ability of elastography in the differentiation of thin and thick cutaneous melanoma is still narrow.

Purpose

To investigate the accuracy of elastography in differentiating thin and thick melanoma, by measuring strain ratio (SR) between the lesion and adjacent dermis and hypodermis.

Material and Methods

We investigated by ultrasound and elastography 52 melanoma lesions in 49 patients. The receiver operating characteristic (ROC) curve method was used to investigate the accuracy of ultrasound and elastographic measurement of SR to surrounding tissue, in the differentiation of thin and thick melanomas. The histopathological measurement of lesions depth called Breslow index was the golden standard test.

Results

Areas under the curve (AUC) showed low accuracy for SR to hypodermis in distinguishing between thin melanomas and others (AUC = 0.739, 95% confidence interval [CI] = 0.508–0.970]) with a cut-off value of 0.950, being the only statistically significant result in matter of elastographic measurements. Highly statistically significant results were obtained for B-mode ultrasound depth measurements of the lesion, with an AUC = 0.970 (95% CI = 0.927–1.0) in discriminating thin melanomas of others and 0.951 (95% CI = 0.869–1.0) in discriminating thick melanomas of other types.

Conclusion

Despite the appearance that SR may correlate with the depth of the lesion, elastography, by measuring the SRs to dermis and hypodermis, does not have enough accuracy in distinguishing thin and thick melanoma.

Increased Marginal Stiffness Differentiates Infiltrative From Noninfiltrative Cutaneous Basal Cell Carcinomas in the Facial Area: A Prospective Study

OBJECTIVES

Basal cell carcinoma (BCC) is the most common dermatologic malignant skin cancer. Infiltrative histologic variants are more aggressive and require wider surgical margins or Mohs surgery, in contrast with noninfiltrative variants, which are commonly treated with standard surgical excision. Elastography has not been used to date to differentiate between the histologic variants of BCC. The purpose of this study was to differentiate infiltrative from noninfiltrative BCCs on elastography.

METHODS

A total of 31 facial BCCs were studied. Preoperatively, color Doppler ultrasound and strain elastographic examinations of the lesions were performed. The size, intralesional vascularization, and presence of hyperechoic dots were considered relevant B-mode and color Doppler variables. Strain ratios of the tumors were obtained with respect to adjacent healthy tissue. Increased marginal stiffness, which was considered hardness in greater than 50% of the tumor margin, was also blindly evaluated. Histologic confirmation and subtyping (infiltrative or noninfiltrative) were performed in all cases.

RESULTS

Infiltrative BCCs did not differ in the size, presence or absence of hyperechoic dots, or vascularization from noninfiltrative BCCs. Strain ratios were similar in both infiltrative and noninfiltrative BCCs (mean ± SD, 1.82 ± 0.879 versus 2.2 ± 1.11). However, infiltrative BCCs had statistically increased marginal stiffness in comparison with noninfiltrative BCCs (88.0% versus 18.8%). Increased marginal stiffness had sensitivity and specificity of 0.89 and 0.82 respectively, with a positive predictive value of 0.67 for infiltrative BCCs and a negative predictive value of 0.95 for noninfiltrative BCCs.

CONCLUSIONS

Histologic variants of BCC have different elastographic patterns. These differences may be of help in preoperative assessments of the BCC subtype and specific surgical planning, avoiding unnecessary skin biopsies.

High-resolution quantitative acoustic microscopy of cutaneous carcinoma and melanoma: Comparison with histology

BACKGROUND

The increased incidence rate of skin cancers during the last decades is alarming. One of the significant difficulties in the histopathology of skin cancers is appearance variability due to the heterogeneity of diseases or tissue preparation and staining process. This study aims to investigate whether the high-resolution acoustic microscopy has the potential for identifying and quantitatively classifying skin cancers.

MATERIAL/METHODS

Unstained standard formalin-fixed skin tissue samples were used for ultrasonic examination. The high-frequency acoustic microscope equipped with the 320 MHz transducer was utilized to visualize skin structure. Fourier transform was performed to calculate the sound speed and attenuation in the tissue.

RESULTS

The acoustic images demonstrate good concordance with the traditional histology images. All histological features in the tumour were easily identifiable on acoustic images. Each skin cancer type has its combination of ultrasonic properties significantly different from the healthy skin.

CONCLUSIONS

High-resolution acoustic imaging strengthened with quantitative analysis shows a potential to work as an auxiliary imaging modality assisting pathologists to lean to the particular decision in doubtful cases. The method can also assist surgeon to ensure the complete resection of a tumour.

Ultrasound as a diagnostic and interventional aid at point-of-care in dermatology clinic: a case report

Ultrasound is currently underutilized in dermatology practice. However, ultrasound provides clinicians with precise and unique information on cutaneous and subcutaneous lesions, while minimizing costs and complications related to more common and invasive diagnostic methods. We report a patient who presented with a tender subcutaneous mass that was diagnosed and treated using point-of-care ultrasound-guidance at the dermatology clinic. Ultrasound revealed features consistent with a ganglion cyst, which was subsequently injected with triamcinolone acetonide under ultrasound-guidance with the resolution of symptoms upon follow-up one month later. Our study demonstrates the utility of ultrasound as an effective, time-efficient diagnostic and interventional aid that can modify dermatology practice.

Elastography reference values of facial skin elasticity

Introduction

With an introduction of new ultrasonographic transducers, skin elastography may find an application in dermatology and aesthetic medicine enabling direct evaluation of various pathological or natural processes.

Aim

To verify which elastographic technique, strain elastography (SE) or shear wave elastography (SWE), is a better candidate for the reference method of facial skin elasticity examination and to determine normal ranges for elastographic parameters in various facial regions.

Material and methods

The study included 71 female volunteers (age: 40–67 years, mean: 52 ±7.5 years). All participants were subjected to SE and SWE of the skin in five anatomical regions: the forehead, suborbital regions, cheeks, nasolabial folds and chin. Reference ranges for elastographic parameters were defined as 95% confidence intervals and ±2 standard deviations and estimated by means of ROC analysis.

Results

Shear wave elastography parameters, but not SE indices, showed strong inverse correlations with the patient age. No significant correlations were found between SE and SWE parameters of the facial skin. In contrast to SWE, no significant correlations were observed between bilateral SE parameters. Based on these findings, SWE was chosen as the reference method to determine age-specific normative values for the elasticity of the facial skin. Reference and cut-off values of SWE parameters were defined for three age groups.

Conclusions

Shear wave elastography is suitable for the determination of elastographic parameters of normal facial skin, and can be used to determine reference ranges thereof. Elasticity of the facial skin decreases considerably with age, and this factor should be considered during determination of reference values for the elastographic parameters.

Ultrasonographic elastography in the evaluation of normal and pathological skin - a review

The aim of this review article is to discuss the role of ultrasonographic elastography, a technique used to quantify tissue stiffness, in the evaluation of normal and pathological skin. A growing body of evidence suggests that elastography may be used for the diagnosis and monitoring of skin pathologies, in particular tumors, and fibrotic and sclerotic processes. Our knowledge about the elastographic parameters of normal skin is sparse, which together with the lack of reference values for cutaneous stiffness constitutes a serious limitation to the use of elastography in some medical disciplines, including aesthetic medicine.

Ultrasound and Infrared-Based Imaging Modalities for Diagnosis and Management of Cutaneous Diseases

Non-invasive bedside imaging tools are becoming more prevalent for assessing cutaneous lesions. Ultrasound used at specific frequencies allows us to assess margins of lesions to minimize the extent of the biopsy that is performed and improve cosmetic outcomes. Vascularity, seen on Doppler ultrasound and contrast-enhanced ultrasound, and stiffness, assessed on tissue elastography, can help differentiate between benign and malignant lesions for clinicians to be more judicious in deciding whether to biopsy. Moreover, research has shown the efficacy in using ultrasound in monitoring flares of hidradenitis suppurativa, a disease affecting apocrine gland-rich areas of the body, for which the current gold standard involves examining and scoring inflammatory lesions with the naked eye. Infrared-based modalities have also been on the uptrend to aid in clinical decision-making regarding suspiciousness of lesions. Reflectance confocal microscopy has lateral resolution that is comparable to histopathology and it has been shown to be an appropriate adjunctive tool to dermoscopy, specifically when evaluating melanomas. Optical coherence tomography has utility in determining lesion thickness because of its depth penetration, and spectrophotometric intracutaneous analysis is becoming more popular as a tool that can be used by general practitioners to know when to refer to dermatology regarding worrisome pigmented lesions. Strides have been made to incorporate electrical impedance spectroscopy alongside dermoscopy in decision-making regarding excision, although the evidence for its use in the clincial setting remains inconclusive. This paper reviews the efficacy and drawbacks of these techniques in the field of dermatology and suggests future directions.

Measurement of shear wave speed dispersion in the placenta by transient elastography: A preliminary ex vivo study

Background

Placental elasticity may be modified in women with placental insufficiency. Shear wave elastography (SWE) can measure this, using acoustic radiation force, but the safety of its use in pregnant women has not yet been demonstrated. Transient elastography (TE) is a safer alternative, but has not yet been applied to the placenta. Moreover, the dispersion of shear wave speed (SWS) as a function of frequency has received relatively little study for placental tissue, although it might improve the accuracy of biomechanical assessment.

Objective

To explore the feasibility and reproducibility of TE for placental analysis, to compare the values of SWS and Young’s modulus (YM) from TE and SWE, and to analyze SWS dispersion as a function of frequency ex vivo in normal placentas.

Materials and methods

Ten normal placentas were analyzed ex vivo by an Aixplorer ultrasound system as shear waves were generated by a vibrating plate and by using an Aixplorer system.

The frequency analysis provided the value of the exponent n from a fractional rheological model applied to the TE method. We calculated intra- and interobserver agreement for SWS and YM with 95% prediction intervals, created Bland-Altman plots with 95% limits of agreement, and estimated the intraclass correlation coefficient (ICC).

Main results

The mean SWS was 1.80 m/s +/- 0.28 (standard deviation) with the TE method at 50 Hz and 1.82 m/s +/-0.13 with SWE (P = 0.912). No differences were observed between the central and peripheral regions of placentas with either TE or SWE. With TE, the intraobserver ICC for SWS was 0.68 (0.50–0.82), and the interobserver ICC for SWS 0.65 (0.37–0.85). The mean parameter n obtained from the fractional rheological model was 1.21 +/- 0.12, with variable values of n for any given SWS.

Conclusions

TE is feasible and reproducible on placentas ex vivo. The frequency analysis of SWS provides additional information about placental elasticity and appears to be able to distinguish differences between placental structures.

Determination of Normal Skin Elasticity by Using Real-time Shear Wave Elastography

OBJECTIVES

To define the reference ranges of normal skin elasticity measurements associated with shear wave elastography (SWE) in healthy volunteers and analyze the factors that may affect SWE.

METHODS

Mean skin thickness and elastic modulus values from 90 healthy volunteers were evaluated with B-mode ultrasonography and SWE in the right fingers and forearms, anterior chest, and abdominal walls. Reference ranges of normal skin elasticity were calculated by using lower and upper limits at the 2.5th and 97.5th percentiles. To investigate the effects of potential factors (site, sex, age, body mass index, and skin thickness) on skin elasticity measurements, a 1-way analysis of variance, the Student t test, and the Pearson correlation test were performed.

RESULTS

Skin elasticity was significantly different at different sites (P < .05). Mean elastic modulus values were 30.3 kPa for the finger, 14.8 kPa for the forearm, 17.8 kPa for the chest wall, and 9.5 kPa for the abdominal wall, and reference ranges of normal skin elasticity were 12.1 to 48.4kPa for the finger, 3.5 to 26.0 kPa for the forearm, 6.6 to 28.9 kPa for the chest wall, and 3.5 to 15.5 kPa for the abdominal wall. Our study revealed that men had higher skin elasticity measurements than women (P < .05), and they were more elevated in participants aged 20 to 50 years than in the other groups at the finger (P < .05). The body mass index and skin thickness had a negligible impact on skin elasticity measurements (P > .05).

CONCLUSIONS

This study revealed that the site, sex, and age should be taken into account when determining the reference ranges of normal skin elasticity by skin elasticity measurements.

The validity and reliability of using ultrasound elastography to measure cutaneous stiffness, a systematic review

BACKGROUND

Ultrasound elastography is an imaging technology which can objectively and non-invasively assess tissue stiffness. It is emerging as a useful marker for disease diagnosis, progression and treatment efficacy.

OBJECTIVE

To examine current, published research evaluating the use of ultrasound elastography for the measurement of cutaneous or subcutaneous stiffness and to determine the level of validity and reliability, recommended methodologies and limitations.

METHODS

MEDLINE, Web of science and Scopus were systematically searched in August 2016 to identify original articles evaluating the use of ultrasound elastography to assess cutaneous stiffness. Relevant studies were then quality evaluated using the Quality Assessment of Diagnostic Accuracy Studies v 2 (QUADAS-2) tool and the Quality Appraisal of Reliability Studies (QAREL).

RESULTS

From a total of 688 articles, 14 met the inclusion criteria for full review. Within the 14 studies, elastography was used to evaluate tumors, systemic sclerosis, lymphedema, abscess, and post-radiation neck fibrosis. Only three robust studies demonstrated good interrater reliability, whereas all validity studies had low sample sizes and demonstrated risks of bias.

CONCLUSION

Robust evidence supporting the use of ultrasound elastography as a diagnostic tool in cutaneous conditions is low, however, initial indicators support further research to establish the utility of ultrasound elastography in dermatology.