Objective Assessment of Area and Erythema of Psoriasis Lesion Using Digital Imaging and Colourimetry

Psoriasis is a non-contagious skin disease which typically consists of red plaques covered by silvery-white scales. It affects about 3% of world population. During treatment, dermatologists monitor the extent of psoriasis continuously to ascertain treatment efficacy. Psoriasis Area and Severity Index (PAS!) is the current gold standard method used to assess the extent of psoriasis. In PAS!, there are four parameters to be scored i.e., the surface area affected, erythema (redness), thickness and scaliness of the plaques. Determining PAS! score is a tedious task and thus it is not used in daily clinical practice. In addition, the PAS! parameters are visually determined and may result in intra-observer and inter-observer variations, even by experienced dermatologists. Objective methods in assessing area and erythema of psoriasis lesion have been developed in this thesis. Psoriasis lesion can be recognized by its colour dissimilarity with normal skin. Colour dissimilarity is represented by colour difference in CIELAB colour space, a widely used colour space to measure colour dissimilarity. Each pixel in CIELAB colour space can be represented by its lightness (L'), hue (hob), and chroma (Cab). Colour difference between psoriasis lesion and normal skin is analyzed in hue-chroma plane of CIELAB colour space. Centroids of normal skin and lesion in hue-chroma space are obtained from selected samples. Euclidean distances between all pixels with these two centroids are then calculated. Each pixel is assigned to the class of the nearest centroid. The erythema of psoriasis lesion is affected by degree of severity and skin pigmentation. In order to assess the erythema objectively, patients are grouped according to their skin pigmentation level. The L* value of normal skin which represents skin pigmentation level is utilized to group the patient into the three skin types namely fair, brown and dark skin types. Light difference (t.L*), hue difference (t.hab), and chroma difference (t.C'ab) of CIELAB colour space between reference lesions and the surrounding normal skin are analyzed. It is found that the erythema score of a lesion can be determined by their hue difference (t.hab) value within a particular skin type group. Out of 30 body regions, the proposed method is able to give the same PAS! area score as reference for 28 body regions. The proposed method is able to determine PAS! erythema score of 82 lesions obtained from 22 patients objectively without being influenced by other characteristic of the lesion such as area, pattern, and boundary

(SEMI)-AUTOMATED ANALYSIS OF MELANOCYTIC LESIONS

Melanoma is a very aggressive form of skin cancer whose incidence has constantly grown in the last 50 years. To increase the survival rate, an early diagnosis followed by a prompt excision is crucial and requires an accurate and periodic analysis of the patient's melanocytic lesions. We have developed an hardware and software solution named Mole Mapper to assist the dermatologists during the diagnostic process. The goal is to increase the accuracy of the diagnosis, accelerating the entire process at the same time. This is achieved through an automated analysis of the dermatoscopic images which computes and highlights the proper information to the dermatologist. In this thesis we present the 3 main algorithms that have been implemented into the Mole Mapper: A robust segmentation of the melanocytic lesion, which is the starting point for any other image processing algorithm and which allows the extraction of useful information about the lesion's shape and size. It outperforms the speed and quality of other state-of-the-art methods, with a precision that meets a Senior Dermatologist's standard and an execution time that allows for real-time video processing; A virtual shaving algorithm, which increases the precision and robustness of the other computer vision algorithms and provides the dermatologist with a hair-free image to be used during the evaluation process. It matches the quality of state-of-the-art methods but requires only a fraction of the computational time, allowing for computation on a mobile device in a time-frame compatible with an interactive GUI; A registration algorithm through which to study the evolution of the lesion over time, highlighting any unexpected anomalies and variations. Since a standard approach to this problem has not yet been proposed, we define the scope and constraints of the problem; we analyze the results and issues of standard registration techniques; and finally, we propose an algorithm with a speed compatible with Mole Mapper's constraints and with an accuracy comparable to the registration performed by a human operator

Markov-Gibbs Random Field Approach for Modeling of Skin Surface Textures

Medical imaging has been contributing to dermatology by providing computer-based assistance by 2D digital imaging of skin and processing of images. Skin imaging can be more effective by inclusion of 3D skin features. Furthermore, clinical examination of skin consists of both visual and tactile inspection. The tactile sensation is related to 3D surface profiles and mechanical parameters. The 3D imaging of skin can also be integrated with haptic technology for computer-based tactile inspection. The research objective of this work is to model 3D surface textures of skin. A 3D image acquisition set up capturing skin surface textures at high resolution (~0.1 mm) has been used. An algorithm to extract 2D grayscale texture (height map) from 3D texture has been presented. The extracted 2D textures are then modeled using Markov-Gibbs random field (MGRF) modeling technique. The modeling results for MGRF model depend on input texture characteristics. The homogeneous, spatially invariant texture patterns are modeled successfully. From the observation of skin samples, we classify three key features of3D skin profiles i.e. curvature of underlying limb, wrinkles/line like features and fine textures. The skin samples are distributed in three input sets to see the MGRF model's response to each of these 3D features. First set consists of all three features. Second set is obtained after elimination of curvature and contains both wrinkle/line like features and fine textures. Third set is also obtained after elimination of curvature but consists of fine textures only. MGRF modeling for set I did not result in any visual similarity. Hence the curvature of underlying limbs cannot be modeled successfully and makes an inhomogeneous feature. For set 2 the wrinkle/line like features can be modeled with low/medium visual similarity depending on the spatial invariance. The results for set 3 show that fine textures of skin are almost always modeled successfully with medium/high visual similarity and make a homogeneous feature. We conclude that the MGRF model is able to model fine textures of skin successfully which are on scale of~ 0.1 mm. The surface profiles on this resolution can provide haptic sensation of roughness and friction. Therefore fine textures can be an important clue to different skin conditions perceived through tactile inspection via a haptic device

From scans to models: Registration of 3D human shapes exploiting texture information

New scanning technologies are increasing the importance of 3D mesh data, and of algorithms that can reliably register meshes obtained from multiple scans. Surface registration is important e.g. for building full 3D models from partial scans, identifying and tracking objects in a 3D scene, creating statistical shape models. Human body registration is particularly important for many applications, ranging from biomedicine and robotics to the production of movies and video games; but obtaining accurate and reliable registrations is challenging, given the articulated, non-rigidly deformable structure of the human body. In this thesis, we tackle the problem of 3D human body registration. We start by analyzing the current state of the art, and find that: a) most registration techniques rely only on geometric information, which is ambiguous on flat surface areas; b) there is a lack of adequate datasets and benchmarks in the field. We address both issues. Our contribution is threefold. First, we present a model-based registration technique for human meshes that combines geometry and surface texture information to provide highly accurate mesh-to-mesh correspondences. Our approach estimates scene lighting and surface albedo, and uses the albedo to construct a high-resolution textured 3D body model that is brought into registration with multi-camera image data using a robust matching term. Second, by leveraging our technique, we present FAUST (Fine Alignment Using Scan Texture), a novel dataset collecting 300 high-resolution scans of 10 people in a wide range of poses. FAUST is the first dataset providing both real scans and automatically computed, reliable ground-truth correspondences between them. Third, we explore possible uses of our approach in dermatology. By combining our registration technique with a melanocytic lesion segmentation algorithm, we propose a system that automatically detects new or evolving lesions over almost the entire body surface, thus helping dermatologists identify potential melanomas. We conclude this thesis investigating the benefits of using texture information to establish frame-to-frame correspondences in dynamic monocular sequences captured with consumer depth cameras. We outline a novel approach to reconstruct realistic body shape and appearance models from dynamic human performances, and show preliminary results on challenging sequences captured with a Kinect

The rotterdam study: 2014 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods

The health and care of children with Down Syndrome

Down Syndrome (DS) affects ~10,500 children in the UK. Individuals with DS continue to have poorer health outcomes compared with the general population, and other forms of intellectual disability. By systematically mapping two decades of paediatric DS literature, I found a general decline in the number of publications, since 2014. The majority of publications utilised observational methodologies, with few interventional (5.6%) or qualitative/mixed-method studies (4.3%). Most publications focused on development & cognition, oncology and neurology; relatively few looked at the prevalence of morbidities and health surveillance. Using a large electronic health record dataset I determined the prevalence of morbidities among individuals with DS (N=4,648, age range 0-75 years), and compared with matched controls. The most prevalent morbidities in the DS cohort were hypothyroidism (30.4%), congenital cardiac disease (27.8%), epilepsy (21.9%) and hearing impairment (19.2%). We also found an increased risk of autism (aOR 7.7), chronic kidney disease (aOR 2.3), inflammatory bowel disease (aOR 2.4), non-accidental injury (aOR 1.9), sleep disordered breathing (SDB) (aOR 6.6) and vitamin-D deficiency (aOR 3.1). Finally, I explored current practice with regard to the routine health surveillance of children with DS, in paediatric departments across the UK. Sixty four departments returned a copy of their local health surveillance protocol. Practice was compared across departments, and with three national guidelines. For congenital cardiac disease, hypothyroidism and hearing/visual impairment, practice appeared to be consistent and compliant with national guidelines. However, in other areas (echocardiogram at transition, SBD, vitamin-D deficiency & renal/liver function), practice was patchy and inconsistent. The findings highlight a need for ongoing research in the field of paediatric DS, targeted at areas of greatest need, and those morbidities which are prevalent in the DS cohort. Furthermore, our findings highlight a need a single, evidence based guideline for the health surveillance of children with DS, to promote high quality, consistent care

Review of photoacoustic imaging plus X

Photoacoustic imaging (PAI) is a novel modality in biomedical imaging technology that combines the rich optical contrast with the deep penetration of ultrasound. To date, PAI technology has found applications in various biomedical fields. In this review, we present an overview of the emerging research frontiers on PAI plus other advanced technologies, named as PAI plus X, which includes but not limited to PAI plus treatment, PAI plus new circuits design, PAI plus accurate positioning system, PAI plus fast scanning systems, PAI plus novel ultrasound sensors, PAI plus advanced laser sources, PAI plus deep learning, and PAI plus other imaging modalities. We will discuss each technology's current state, technical advantages, and prospects for application, reported mostly in recent three years. Lastly, we discuss and summarize the challenges and potential future work in PAI plus X area

Facilitators and barriers for implementation of a UK standardized core curriculum for medical schools, a dermatology perspective

There is no standard medical curriculum across UK medical schools. The General Medical Council (GMC) provides generic learning outcomes for medical schools.Specialty curriculum implementation in medical schools is varied and inconsistent. This PhD thesis aimed to explore the facilitators and barriers for implementation of a nationally recommended specialty core-curriculum for UK medical schools, using Dermatology as a specialty perspective. Methodology and methods: A mixed-methods research (MMR) research methodology was used and multiple methods incorporated to address the research question. A scoping review was conducted to identify the available specialty curricula for UK medical schools, and the drivers for their development. A curriculum mapping study at a UK medical school reviewed the local undergraduate (UG) dermatology curriculum against the national British Association of Dermatologists’ (BAD) standards. An online cross-sectional questionnaire survey of UK dermatology UG teaching leads helped to understand the possible facilitators and barriers to specialty- specific implementation across UK medical schools. Finally, semi-structured interviews with Deans of medical education of UK schools were undertaken to gather their perspective on specialty curriculum implementation. Results: The scoping review provided a comprehensive overview of the curricula developed by specialties, in alignment with GMC outcomes. Twenty-six specialties developed a core curriculum to provide specialty specific guidance to medical schools on minimum standards for knowledge and skills required for all graduates. Drivers for development of these included fear for patient safety, burden of disease, medical schools not including it in their curricula and graduates feeling ill prepared to practice confidently and safely. Curriculum mapping enabled visualisation of dermatology and its relationships between other specialties. The cross-sectional survey revealed knowledge gaps amongst UG leads with respect to mapping and blueprinting of core-curricula and the GMC’s proposed implementation of the Medical Licensing Assessment (MLA) in 2024-25 (Medical licensing assessment – GMC, 2020). Perceived barriers to curriculum implementation included National Health Service (NHS) clinical workloads, dermatology not deemed a priority in school curricula, and difficulty influencing changes at medical school level. The Deans of Medical Education recognised the importance of including dermatology in the undergraduate curriculum. The skill set, and enthusiasm of the ‘specialty champions’ was an important factor for engaging medical students. National and local political driven health agendas (e.g. the UK government, the GMC, MLA, and Health education boards) influenced teaching, learning and assessment methods. Cultural attitudes between specialties, NHS Trusts, and Universities, and student feedback determined how well curriculum integration took place. Paucity of adequate clinical staff for teaching, and impact of Covid-19 pandemic were other challenges that influenced curriculum implementation. Perceived facilitators included improved workforce planning with support from inter-professional educators. Transparency in funding to the NHS Trusts towards UG medical teaching and educational governance were considered paramount in ensuring monies followed and reflected the students’ experience. Strategies to develop UG lead roles as medical educators included appropriate recognition in job plans and review of professional development in yearly appraisals. Medical education qualifications and leadership skills were considered valuable for clinicians or academics taking on roles as UG education leads. This research study identifies facilitators and barriers for UG specialty-specific (dermatology) curriculum implementation in UK, which could be generalizable and relevant to other specialty core-curricula. The study supports creation of practical strategies, and provides a basis for national collaborative ways to improve implementation of specialty core-curricula across medical schools