What dermatologists should know about digital imaging

Diagnostics Using Non-Invasive Technologies in Dermatological Oncology

The growing incidence of skin cancer, with its associated mortality and morbidity, has in recent years led to the developing of new non-invasive technologies, which allow an earlier and more accurate diagnosis. Some of these, such as digital photography, 2D and 3D total-body photography and dermoscopy are now widely used and others, such as reflectance confocal microscopy and optical coherence tomography, are limited to a few academic and referral skin cancer centers because of their cost or the long training period required. Health care professionals involved in the treatment of patients with skin cancer need to know the implications and benefits of new non-invasive technologies for dermatological oncology. In this article we review the characteristics and usability of the main diagnostic imaging methods available today.

Artificial Intelligence in Dermatology Image Analysis: Current Developments and Future Trends

BACKGROUND

Thanks to the rapid development of computer-based systems and deep-learning-based algorithms, artificial intelligence (AI) has long been integrated into the healthcare field. AI is also particularly helpful in image recognition, surgical assistance and basic research. Due to the unique nature of dermatology, AI-aided dermatological diagnosis based on image recognition has become a modern focus and future trend. Key scientific concepts of review: The use of 3D imaging systems allows clinicians to screen and label skin pigmented lesions and distributed disorders, which can provide an objective assessment and image documentation of lesion sites. Dermatoscopes combined with intelligent software help the dermatologist to easily correlate each close-up image with the corresponding marked lesion in the 3D body map. In addition, AI in the field of prosthetics can assist in the rehabilitation of patients and help to restore limb function after amputation in patients with skin tumors.

THE AIM OF THE STUDY

For the benefit of patients, dermatologists have an obligation to explore the opportunities, risks and limitations of AI applications. This study focuses on the application of emerging AI in dermatology to aid clinical diagnosis and treatment, analyzes the current state of the field and summarizes its future trends and prospects so as to help dermatologists realize the impact of new technological innovations on traditional practices so that they can embrace and use AI-based medical approaches more quickly.

High-frequency ultrasound characterization of normal skin. Skin thickness and echographic density of 22 anatomical sites

BACKGROUND/AIMS

Variation in skin thickness relative to anatomical site was little studied in the past. Biopsy cutting and histological processing change tissue geometry. High-frequency ultrasound allows in vivo measurement of skin thickness of multiple sites. The object was to map regional differences in skin thickness.

METHODS

22 different anatomical sites were studied. The Dermascan C (20 MHz) was used. The acoustic density of the dermis and the epidermal entrance echo was analyzed by the in-built image analysis software. 18 healthy volunteers aged 24-41 years were studied.

RESULTS

Extremity skin was thinner than truncal skin, and acoustically dense. Females had thinner and more dense skin in comparison with males. Skin of the palm, sole and the head was thick but weak in density, and the biological variation in the dermis/subcutaneous tissue interphase does not allow highly accurate evaluation in these special sites. There was an overall inverse correlation between skin thickness and acoustic density with thin skin being dense and thick skin being relatively echo-poor.

CONCLUSIONS

Skin thickness and acoustic density reflecting intradermal structure exhibit systematic regional variation with thin and dense skin on extremities in comparison with the trunk and special ultrasound profiles in selected sites such as the face, the palp and sole. Female skin is thinner and more dense in comparison with male skin.

Update on techniques for the quantitation of facial skin characteristics

The purpose of this article is to review the strategies and methods for quantifying treatment outcomes, perhaps defined by the consumer/patient as a "decrease in perceived age." The demand for the rejuvenation of facial skin is expected to increase as the population ages and seeks optimal outcomes from the array of available treatment modalities. This information will be of value to the plastic surgeon in collaborating with patients on evaluation and treatment strategies.

Ultrasound and 3D Skin Imaging: Methods to Evaluate Efficacy of Striae Distensae Treatment

Background. Over time, the striae rubra develop into striae alba that appear white, flat, and depressed. It is very important to determine the optimum striae management. In order to evaluate the effectiveness of these therapies, objective measurement tools are necessary. Objective. The aim of this study is to evaluate if ultrasonography and PRIMOS can be used to obtain an objective assessment of stretch marks type and stage; furthermore, we aim to apply these techniques to evaluate the efficacy of a topical treatment. Methods. 20 volunteers were enrolled with a two-month study. A marketed cosmetic product was used as the active over one body area. The controlateral area with stretch marks was treated with a "placebo" formulation without active, as a control. The instrumental evaluation was carried out at the beginning of the trial (baseline values or t(0)), after 1 month (t(1)), and at the end of the study (t(2)). Results. PRIMOS was able to measure and document striae distensae maturation; furthermore, ultrasound imaging permitted to visualize and diagnose the striae. Statistical analysis of skin roughness demonstrated a statistically significant reduction of Rp value only in a treated group. In fact, the Rp value represented a maximum peak height in the area selected. These results demonstrated that after two months of treatment only the striae rubra can be treated successfully. Conclusions. This work demonstrated that the 22MHz ultrasound can diagnose stretch marks; PRIMOS device can detect and measure striae distensae type and maturation. Furthermore, the high-frequency ultrasound and the 3D image device, described in this work, can be successfully employed in order to evaluate the efficacy of a topical treatment.

Scaled Healing Assessment Index: a novel method for measuring the degree of wound bed preparation

BACKGROUND/PURPOSE

The color of a wound bed reflects its degree of 'cleanness' and serves as an indicator in evaluating the progression of wounds toward healing. We were aiming to develop a standard tool, for use in clinical research studies, which would analyze and provide objective data as to the color distribution of wound surfaces. To this end, we designed the 'Scaled Healing Assessment Index' algorithmic tool to provide a scoring system to determine the average color of wound surfaces.

METHODS

The scale is graded from 1 to 10, with 1 representing the most unclean yellow wound, and 10 representing the optimal red wound. In order to test the accuracy of the software, 102 chronic wounds in 88 patients were examined. Each wound was assessed using a grading from 1 to 10, according to its color, using three separate methods: (1) by three dermatologists [average clinical score (ACS)] in the outpatient clinic; (2) by three other dermatologists with the same wounds presented on a computer screen [average photo score (APS)]; and (3) by the Scaled Healing Assessment Index [software score (SS)]. The results of the three methods were examined statistically using Pearson's correlation.

RESULTS

We found a high correlation between the ACSs and the SSs (0.86), between the APSs and the SSs (0.863), as well as the ACSs with the APSs (0.95).

CONCLUSION

The Scaled Healing Assessment Index algorithm provides objective and reliable data, and can be used in research studies aimed at examining the beneficial effect of products intended for wound healing.

Three-dimensional documentation of wound healing: first results of a new objective method for measurement

BACKGROUND

The objective assessment of wound healing is one essential parameter of quality assurance in a modern chronic wound management program. In the past assessment has been based exclusively on a two-dimensional measurement of the wound surface with planimetry or digital photo documentation in combination with such measurements. An objective method for measuring the volume of chronic wounds has not yet been available.

PATIENTS AND METHODS

In cooperation with the company RSI, we linked digital photography, optical raster by means of digital scanner, and picture processing software (DigiSkin) for an exact three-dimensional image of chronic wounds. The generated point clouds allow the visual, computer-assisted three-dimensional quantification and can document the course of healing of chronic wounds.

RESULTS

In comparison to currently available systems, our new method makes possible the objective measurement of volume changes and wound healing course in chronic wounds.We demonstrate the utility of the system in reference to three patients with chronic venous leg ulcers.

CONCLUSIONS

Using this new, objective three-dimensional wound measurement system,it is possible to reliably quantify changes in wound healing for the first time. Future clinical studies have a new option for the gathering of data which will facilitate evidenced-based conclusions.

Current technologies for the in vivo diagnosis of cutaneous melanomas

The rising incidence of cutaneous malignant melanoma has been observed in the past decades. Currently, there is no cure for metastatic melanoma; only early diagnosis followed by prompt excision of cutaneous lesions ensures a good prognosis. The clinical ABCD rule is created as a framework for differentiating melanomas from benign pigmented skin lesions, and it serves as the basis for current clinical diagnosis. The ABCD rule relies on four simple clinical morphologies of melanoma: 1) Asymmetry, 2) Border irregularity, 3) Color variegation, and 4) Diameter greater than 6 mm. Although it is valuable, it has its limitations. Currently, the diagnostic accuracy for physicians is about 65%. This statistic implies that 1) melanomas with subtle signs are missed as benign lesions, and 2) benign lesions are over diagnosed as melanomas, which lead to unnecessary biopsies.

Instruments and new technologies for the in vivo diagnosis of melanoma

The principal objective of screening individuals at risk for melanoma is detection of cutaneous melanoma during the curable stages of its early evolution. Unaided visual inspection of the skin is often suboptimal at diagnosing melanoma. Improving the diagnostic accuracy for melanoma remains an area of active research. These research efforts have focused on both the detection of early melanoma and the in-depth evaluation of suspicious pigmented lesions for the presence or absence of melanoma. Numerous instruments are under investigation to determine their usefulness in imaging and ascertaining a correct in vivo diagnosis of melanoma. It is anticipated that some of these tools, alone or in combination, will improve our ability to differentiate, in vivo, melanoma from its simulators. Ultimately, these advances may prevent unnecessary biopsies (increased specificity) while increasing the sensitivity for diagnosing melanoma. This article reviews the current instruments and new technologies for the in vivo diagnosis of melanoma. Learning objective At the conclusion of this learning activity, participants should be acquainted with the instruments designed to facilitate the early detection of melanoma. They should also be familiar with the basic technology behind these instruments and should recognize the potential benefits and limitations inherent in each.

Imaging the skin

Since the discovery of X-rays, the use of imaging technology has continued to play an important role in medicine. Technological advancements have led to the development of various imaging modalities, most of which have been used to image organs deep within the human body. More recently, attention has focused on the application of imaging technology for evaluation of the skin. A variety of techniques are currently being used to examine the skin and these include specialized photography, surface microscopy, ultrasound, laser Doppler perfusion imaging, confocal microscopy, and magnetic resonance imaging. These modalities can provide information that can assist in the management of skin problems. Although many of these techniques are still undergoing research, they are showing promise as useful clinical tools in dermatology.

Telemedicine framework and applications in dermatology and ophthalmology

Medicine has to balance between the advantages and costs of new technology. As the significance of technical aids has increased, medicine has become more tightly bound to technology. Telemedicine is one of the fastest developing fields, as its development is connected to the development of telecommunication and information technology. Technology sets the ultimate restrictions to telemedicine. However, most challenges are nontechnical. Fast development makes it difficult to perform generalizable studies on the field, and the lack of practical, applicable standardization hinders telemedical system design. The cost of technology is quickly falling compared with the cost of human labour. Because of these factors the efficient use of telemedicine requires strategic decisions at the level of the organization as well as more research concerning the effects of telemedicine on medical practice. This article describes the telemedical frame of reference by using dermatology and ophthalmology as examples.

Teleophthalmology: rationale, current issues, future directions

Relatively little information exists concerning the delivery of ophthalmic services via telemedicine, yet ophthalmology is particularly amenable to the utilization of such applications. This paper discusses the technological issues pertinent to the research, development, and assessment of teleophthalmology delivery systems and begins to define the parameters that will determine the sustainability of teleophthalmology. A prototype urban teleophthalmology delivery system is presented in the context of improving access to eye care for an underserved inner-city population. Potential enhancements to the prototype telephthalmology system are discussed.

Differentiation between pigmented Spitz naevus and melanoma by digital dermoscopy and stepwise logistic discriminant analysis

Epiluminescence light microscopy (ELM) has proven useful in the diagnosis of pigmented skin lesions (PSLs). However, in some cases this technique does not sufficiently increase the diagnostic accuracy in distinguishing pigmented Spitz naevi (PSNs) from melanoma. With the aim of obviating these problems of qualitative interpretation, methods based on the mathematical analysis of PSLs, such as digital dermoscopy analysis (DDA), have recently been developed. In the present study we used a digital dermoscope (DBDermo-MIPS, Dell'Eva-Burroni) to analyse PSNs and melanomas with similar clinical and dermoscopic features for any correlation between variables and to determine its discriminating power with respect to histological diagnosis. The 100 lesions underwent histological examination by three experienced dermatopathologists and were identified as PSNs (43) or melanomas (57). Thirty-six parameters were identified as possible discriminating variables and were grouped in four categories: geometry, colour, texture, and islands of colour. Statistical analysis was used to identify the variables with the highest discriminating power. Stepwise discriminant analysis selected only four variables: entropy, minimum diameter, red lesion value and peripheral dark (the means of these variables were higher in melanomas than in PSNs). Thus the combined use of digital dermoscopy and stepwise logistic discriminant analysis made it possible to single out the best objective variables for distinguishing PSN and melanoma.

Computer-aided epiluminescence microscopy of pigmented skin lesions: the value of clinical data for the classification process

Early melanoma is often difficult to differentiate from benign pigmented skin lesions (PSLs). Digital epiluminescence microscopy (DELM) and automated image analysis could represent possible aids for inexperienced clinicians. We designed an automated computerized image analysis system that has the potential for use as an additional tool for the differentiation of melanoma from dysplastic naevi and common naevi. The PC-based pilot system was attached to a common DELM system as the image source. Digital images of PSLs were automatically segmented and a panel of 107 morphological parameters were measured. Additionally, seven clinical parameters were evaluated and used as an additional source of information. Neural networks were then trained to distinguish melanoma from benign PSLs. One class of networks was trained solely based on the morphometric features, whereas the second class of networks was trained on the combination of morphometric and clinical features. The automatic segmentation algorithm was correct in 96% of cases. Using three-way receiver operating characteristic (ROC) analysis, for networks trained solely on morphometric features the volume under surface (VUS) was 0.617 (SD 0.036). The performance was significantly better for networks trained on the combination of both morphometric and clinical features (VUS = 0.682, SD 0.035). In a dichotomous model, distinguishing benign lesion (common naevi + dysplastic naevi) from melanoma, the area under the curve (AUC) from two-way ROC analysis was 0.942 (SD 0.018) for networks trained solely on morphometric features and 0.968 (SD 0.012) for those trained on the combination of clinical and morphometric data (P= NS). Automated feature extraction from PSLs and the training of neural networks as classifiers has thus shown satisfactory performance in a large scale experiment. The addition of clinical data significantly increases the diagnostic performance for distinguishing three classes of lesions (i.e. common naevi, dysplastic naevi and melanoma). Such integrated systems hold promise as a decision aid for the diagnosis of PSLs.

Intensive care unit telemedicine: alternate paradigm for providing continuous intensivist care

OBJECTIVE

Intensive care units (ICUs) account for an increasing percentage of hospital admissions and resource consumption. Adverse events are common in ICU patients and contribute to high mortality rates and costs. Although evidence demonstrates reduced complications and mortality when intensivists manage ICU patients, a dramatic national shortage of these specialists precludes most hospitals from implementing an around-the-clock, on-site intensivist care model. Alternate strategies are needed to bring expertise and proactive, continuous care to the critically ill. We evaluated the feasibility of using telemedicine as a means of achieving 24-hr intensivist oversight and improved clinical outcomes.

DESIGN

Observational time series triple cohort study.

SETTING

A ten-bed surgical ICU in an academic-affiliated community hospital.

PATIENTS

All patients whose entire ICU stay occurred within the study periods.

INTERVENTIONS

A 16-wk program of continuous intensivist oversight was instituted in a surgical ICU, where before the intervention, intensivist consultation was available but there were no on-site intensivists. Intensivists provided management during the intervention using remote monitoring methodologies (video conferencing and computer-based data transmission) to obtain clinical information and to communicate with on-site personnel. To assess the benefit of the remote management program, clinical and economic performance during the intervention were compared with two 16-wk periods within the year before the intervention.

MEASUREMENTS AND MAIN RESULTS

ICU and hospital mortality (observed and Acute Physiology and Chronic Health Evaluation III, severity-adjusted), ICU complications, ICU and hospital length-of-stay, and ICU and hospital costs were measured during the 3 study periods. Severity-adjusted ICU mortality decreased during the intervention period by 68% and 46%, compared with baseline periods one and two, respectively. Severity-adjusted hospital mortality decreased by 33% and 30%, and the incidence of ICU complications was decreased by 44% and 50%. ICU length of stay decreased by 34% and 30%, and ICU costs decreased by 33% and 36%, respectively. The cost savings were associated with a lower incidence of complications.

CONCLUSIONS

Technology-enabled remote care can be used to provide continuous ICU patient management and to achieve improved clinical and economic outcomes. This intervention's success suggests that remote care programs may provide a means of improving quality of care and reducing costs when on-site intensivist coverage is not available.

The effect of decreasing digital image resolution on teledermatology diagnosis

OBJECTIVE

To determine the effect of degraded digital image resolution (as viewed on a monitor) on the accuracy and confidence of dermatologic interpretation.

MATERIALS AND METHODS

Eight dermatologists interpreted 180 clinical cases divided into three Logical Competitor Sets (LCS) (pigmented lesions, non-pigmented lesions, and inflammatory dermatoses). Each case was digitized at three different resolutions. The images were randomized and divided into (9) 60-image sessions. The physicians were completely blinded concerning the image resolution. After 60 seconds per image, the viewer recorded a diagnosis and level of confidence. The resultant ROC curves compared the effect of LCS, level of clinical difficulty, and resolution of the digital image. One-way analysis of variance (ANOVA) compared the curves.

RESULTS

The areas beneath the ROC curves did not demonstrate any consistently significant difference between the digital image resolutions for all LCS and levels of difficulty. The only significant effect observed was amongst pigmented lesions (LCS-A) where the ROC curve area was significantly smaller in the easy images at high resolution compared to low and medium resolutions. For all other ROC curve comparisons within LCS-A, at all other levels of difficulty, as well as within the other LCS at all levels of difficulty, none of the differences was significant.

CONCLUSION

A 720 x 500 pixel image can be considered equivalent to a 1490 x 1000 pixel image for most store-and-forward teledermatology consultations.

The uses of digital photography in dermatology

Digital photography is a powerful tool that is transforming the specialty of dermatology by integrating patient and practice management. The fundamentals of digital imaging are discussed, and an approach to the selection of a digital camera and its associated hardware and software is provided. The applications of this technology to patient and practice management are addressed, and the ethical implications of digital tampering are also discussed.

The history of teledermatology in the Department of Defense

The Department of Defense (DoD) healthcare system supports the medical needs of service members while engaged in a variety of missions frequently in isolated, remote, and austere locations. As a result, the DoD has been a leader in the development of telemedicine, including teledermatology as a way to provide "good medicine in bad places." A brief technical history of teledermatology, representative DoD experiences including military unique concerns, and a novel approach to increase the access of DoD teledermatology consultation are presented in this article.

Ultrasound biomicroscopy. High-frequency ultrasound imaging of the eye at microscopic resolution

UBM presents us with a new method of imaging the anterior segment of the eye at high resolution. Its strengths lie in its ability to produce cross-sections of the living eye at microscopic resolution without violating the integrity of the globe. UBM, although lacking the resolution of optical microscopy, gives us images in living eyes without affecting the internal relationships of the structures imaged. There are many other applications of this new imaging method. Examples of other uses include imaging adnexal pathology, assessing corneal changes with refractive surgery, the assessment of trauma, and determination of intraocular lens position.

A telemedicine consultative service for the evaluation of patients with urolithiasis

OBJECTIVES

A 6-month pilot teleconsultative project linking Georgetown University Medical Center (GUMC) in Washington, DC, and City Hospital in Martinsburg, West Virginia, 90 miles away, was designed to assess the effectiveness of telemedicine on the clinical decision-making process for patients with urolithiasis.

METHODS

The telemedicine system designed and tested for this project was based on a PC-based platform. Videoconferencing and review of the patient's imaging studies were performed over an Integrated Service Digital Network (ISDN) with 3 Basic Rate (BRI) ISDN lines providing a 336-kilobytes/s bandwidth through an Inverse Multiplexor (IMUX). Treatment options were recorded for the clinical trial group and a simulated study group by the consulting urologist after the initial telephone consultation, after the telemedicine consultation, and after examination of those patients transferred to GUMC.

RESULTS

A total of 32 telemedicine consultations were performed: 14 in the clinical trial group and 18 in the simulated study group. The recommendation of the consulting urologist at the tertiary center was altered in 12 patients (37.5%) after the telemedicine consultation compared with the recommended treatment after the initial telephone consultation.

CONCLUSIONS

In the evaluation of patients with urolithiasis, this telemedicine application enhanced the clinical decision-making process by allowing for improved quality of care through immediate access and effective transfer of information between the referring urologist, the patient, and the stone center specialist.

The use of a digital imaging system in a dermatologic surgery practice

BACKGROUND

Digital imaging systems are now commercially available, reasonably affordable, and much improved in quality.

OBJECTIVE

To present our 2-year experience with a digital imaging system in Mohs and dermatologic surgery practice and to inform readers of the equipment needed, its cost, uses, advantages, and disadvantages compared with conventional photography.

CONCLUSION

The advantages of a digital imaging system include quality images, easy storage and retrieval, and cost-effectiveness. The disadvantages are few: a substantial initial investment and the training of office personnel in its use and maintenance. Uses include monitoring nevomelanocytic lesions, surgical photo documentation, medical records, and a photographic research database.

Reliability of computer image analysis of pigmented skin lesions of Australian adolescents

BACKGROUND

The diagnosis of melanomas at an early stage is associated with improved survival, so the recognition of changes in pigmented skin lesions over time is important. We have developed a computer imaging system with the aim of assisting clinicians in differentiating early melanomas from benign pigmented skin lesions. The objective of this study was to investigate the system's reliability over time in measuring diagnostic characteristics of pigmented skin lesions, including their color, size, shape, and distinctness of boundary.

METHODS

We captured video images of 5 lesions, all larger than 2 mm in greatest dimension, on each of 66 Australian adolescents on 2 occasions approximately 1 month apart. Features extracted by computer image analysis included area, perimeter, and regularity of outline of the lesions, the mean and standard deviation of reflectance at red, green, and blue wavelengths, and the mean and standard deviation of the gradients of red, green, and blue reflectance at the lesion boundary.

RESULTS

All measurements showed moderate to high reliability (intraclass correlation coefficients 0.66-0.94), except for the standard deviations of the color gradients, whose reliability improved to moderate levels (0.68-0.71) when the mean of 5 lesions was considered. For most outcomes, reasonable within subject reliability was achieved when five lesions per subject were measured.

CONCLUSIONS

These results, in combination with previous work demonstrating the reasonable ability of this computer imaging system to discriminate between malignant melanomas and other pigmented lesions, indicates that the system has the potential to become a useful tool for clinicians in following people with pigmented lesions over time to detect early malignant changes.

Intraobserver agreement in interpretation of digital epiluminescence microscopy

BACKGROUND

Although a major problem with the classification of epiluminescence microscopy (ELM) findings is the lack of standard definitions, reproducibility of the criteria proposed has never been investigated.

OBJECTIVES

Our purposes were (1) to perform a review of four major published classifications to obtain a set of apparently well-defined ELM variables and descriptors and (2) to evaluate the ability of one of us to report consistently ELM findings in melanocytic lesions according to these criteria.

METHODS

Intraobserver agreement (with a set of 44 selected descriptors) between two readings of 150 digital ELM images was evaluated with the kappa (kappa) statistic. Subgroups of descriptors were compared for kappa value distribution.

RESULTS

The median kappa value for the whole series of descriptors was 0.66. Median kappa did not vary significantly among the four classification systems (kappa = 0.61 to 0.67). Agreement was significantly better as to the presence or absence of ELM findings (kappa range, 0.39 to 1.00; median kappa, 0.77) compared with agreement as to their distribution (kappa range, 0.10 to 0.79; median kappa, 0.47; p = 0.0007) and their width, thickness, and size (kappa range, 0.06 to 0.83; median kappa, 0.39; p = 0.0075).

CONCLUSION

Although nothing can be inferred from a single study, descriptors associated with low intraobserver agreement are likely to be inadequately defined.

Image processing in the study of wound healing

All wound care products that are said to be suitable for wound cleaning should preferably be evaluated with an observer-blind, quantitative system, as described above.

Computer screening for early detection of melanoma--is there a future?

Computer image analysis in the study of pigmented lesions is critically examined and discussed in the light of the current published data. The potential for objective analysis by computers as a possible screening aid for the inexperienced clinician is discussed. The future for this technology is exciting if handled with care.

20 MHz sonography, colorimetry and image analysis in the evaluation of psoriasis vulgaris

For objective evaluation of the treatment of psoriasis vulgaris standard techniques are desirable. They should be reproducible, sensitive and non-invasive. In this study non-invasive bioengineering techniques, especially high frequency/high resolution ultrasound for measurement of the healing of psoriasis vulgaris were evaluated. Fifty patients with chronic stationary plaque type psoriasis participated in a prospective study; in each patient two psoriatic plaques were examined by means of sonography, colorimetry and image analysis during treatment until complete resolution had occurred. Skin thickness and density could be quantified by means of high frequency ultrasound. In active psoriatic lesions, an echopoor area underneath the entry echo in the ultrasound image caused by acanthosis and inflammatory infiltrate is typical. Under therapy the thickness of this echopoor area diminishes while its density increases. Intensity of the erythema especially the decrease of erythema through healing could not exactly be quantified with the colorimeter because the 'Lab'-CIE-colour representation system cannot distinguish well enough between the colours red and brown. Image analysis allowed to measure the sizes of the psoriatic plaques and to quantify their resolution under therapy. The measuring of plaque size by the aid of computer based image analysis is possible and useful.

A 40-100 MHz B-scan ultrasound backscatter microscope for skin imaging

There is a growing interest in high resolution, subsurface imaging of cutaneous tissues using higher frequency ultrasound, and several commercial systems have been developed recently which operate at 20 MHz. Some of the possible applications of higher frequency skin imaging include tumour staging, boundary definition, and studies of the response of tumours to therapy, investigations of inflammatory skin conditions such as psoriasis and eczema, and basic studies of skin aging, sun damage and the effects of irritants. Investigation of these areas is quite new, and the role of ultrasound skin imaging is continuing to evolve. Lateral resolution in the 20 MHz imaging systems ranges from 200 to 300 microns, which limits imaging applications to cutaneous structures which are relatively large in size. In this paper, a real-time ultrasound backscatter microscope (UBM) for skin imaging is described which operates in the 40-100 MHz range, providing axial resolution between 17 and 30 microns and lateral resolution between 33 and 94 microns. This improvement in resolution over current skin ultrasound systems should prove useful in determining the margins of small skin lesions, and in obtaining more precise, in vivo skin thickness measurements to characterize nonmalignant skin disease. Example images of normal skin, seborrhoeic keratosis and malignant melanoma illustrate the imaging potential of this system.

Computerized digital image analysis: an aid for melanoma diagnosis--preliminary investigations and brief review

Both digital imaging and epiluminescence microscopy hold promise for improved early detection of cutaneous melanoma. Several centers have been actively working in these areas during the past decade. These experiences and preliminary work based on the image capture of 83 pigmented lesions at our center using a prototype digital imaging system (SKINVIEW) are described. This system is based, in part, on the analysis of lesional morphologic features, such as shape, border, and radii. Histopathologic correlation was matched against these features to assess the efficacy of diagnosis. At our center, these parameters alone were not sufficient to discriminate between benign and malignant lesions, in part, because the melanomas were, in general, early lesions and many of the nevi were sufficiently clinically atypical to require removal for discrimination from melanoma. In addition, technical improvements in the image capturing and processing mechanism are needed. Rapid progress in this area is anticipated.

Three-dimensional imaging for diagnostic ultrasound in dermatology

BACKGROUND

Visual examination and cutaneous biopsies, two major tools in dermatologic diagnosis, do not provide structural information regarding the entire tissue volume.

OBJECTIVE

Our purpose was to develop a high-resolution ultrasound system that quickly, with minimal operator interaction, displays structural data on the entire tissue volume.

METHODS

A prototype ultrasound B-scan system was developed and operated at nominal center frequencies between 35 and 50 MHz, with computer processing of data to produce three-dimensional images. These images displayed as three-dimensional "blocks" can be sectioned to provide multiple images of internal structure (i.e., "acoustic biopsies").

RESULTS

B-scans and associated three-dimensional images were obtained from assorted skin sites in selected patients.

CONCLUSION

This technique provides a valuable diagnostic tool that is now being further evaluated.

Principles and applications of ultrasound backscatter microscopy

The development of ultrasound backscatter microscopy (UBM) is described together with initial clinical and biological applications. UBM is essentially an extension of the powerful B-mode backscatter methods developed for clinical imaging in the 3-10-MHz frequency range. The development of new high sensitivity transducers in the 40-100-MHz range now permits visualization of tissue structures with resolution approaching 20 mum and a maximum penetration of approximately 4 mm. The performance characteristics and trade-offs of these new polymer and ceramic devices are reviewed, and the implementation of high-frequency imaging systems is described. Initial clinical applications of UBM include ophthalmic, skin, and intravascular imaging. Examples of images and progress in these areas are presented. The biological application of UBM is illustrated by studies of drug uptake in living tumor spheroids. Significant increases in backscatter levels resulting from drugs targeting oxic and hypoxic cell populations are demonstrated.

Magnetic resonance imaging evaluation helps to delineate a recurrent skin cancer present under the skin flap

A case of recurrent squamous cell carcinoma under a skin flap as confirmed and delineated by magnetic resonance imaging (MRI) is described. This report illustrates a potentially new indication for MRI in clinical dermatology, namely, to define skin cancer recurrences under skin flaps and grafts and to determine the extent of underlying tissue involvement. The cost-effectiveness of MRI and the use of gadolinium, an MRI contrast agent, in the evaluation of skin tumors are also addressed.

Digital imaging in dermatology

In this article we discuss the recent surge in activity in digital imaging in dermatology. The key role of digital imaging as an adjunct to detection of early malignant melanoma, with application in following patients with the dysplastic nevus syndrome, is explored. Other current and future uses of digital imaging in image archiving, in clinical studies such as hair growth studies, and in telediagnosis are reviewed. We review the varying research activities of image analysis laboratories participating in the dermatology image researching group. Research laboratories included in this group are at Oregon Health Sciences University, Xerox Corporation, University of Arizona, University of Cincinnati, University of Munich, University of Wurzburg, University of Arkansas, Harvard University, Southern Illinois University-Edwardsville, Johns Hopkins University, National Institutes of Health, and University of Missouri at Columbia and Rolla. The role of new imaging devices in dermatology including the "nevoscope" and the dermatoscope is explored. Goals and challenges for the new technology are discussed.