Raman spectroscopy and diffuse reflectance spectroscopy for diagnosis of human cancer and acanthosis nigricans

Cancer and diabetes are common chronic diseases in today\u27s world causing numerous deaths in adults as well as children. Most common types of cancers in adults include prostate, lung, breast, colorectal and head and neck squamous cell carcinoma, while among children; leukemia, and brain and central nervous system cancers are quite common. In each of these cases, early detection of the cancer or disease dramatically increases the chances of successful treatment. In recent years, there has been much interest in using Raman spectroscopy and diffuse reflectance spectroscopy as analytical optical spectroscopic methods for early diagnosis of diseases. Raman spectroscopy can be used to measure changes in the bio-molecular composition of a tissue specimen, and diffuse reflectance spectroscopy can measure chromophores of the skin. In this research, archived (formalin-fixed paraffin processed) tissues of head and neck squamous cell carcinoma, prostate, and pediatric tumors have been investigated using Raman spectroscopy. We have utilized statistical methods such as principal component analysis (PCA) and discriminant function analysis (DFA) to analyze the spectral output and distinguish between normal and cancerous tissues. The results show cancerous tissues can be successfully distinguished from normal tissues in three cancer types in ex vivo. However, due to loss of biochemical in the tissue processing (paraffinizing and deparaffinizing procedure), the prediction ability of the archived tissues are less compared to frozen tissues as observed in the pediatric tumor investigation. We also investigated the diagnostic capability of diffuse reflectance spectroscopy and colorimetry on a skin disease, acanthosis nigricans in vivo. The aim is to quantify and characterize the skin color change associated with acanthosis nigricans skin disease in insulin-resistant obese individuals. We observe both the instruments can be utilized to detect acanthosis nigricans with more than 87% sensitivity and 94% specificity when combined with advanced chemometric methods

L-Mesitran® in the management of canine otitis externa

Dissertação de Mestrado Integrado em Medicina VeterináriaAt a time when antimicrobial resistance is rising steadily and the involved microorganisms are demonstrating zoonotic potential, honey and its derived products may prove useful in this ongoing battle. Otitis externa in dogs is considered to be one of the most prominent causes for presentation at veterinary practice. Some of the regularly administered agents in otitis treatments are no longer effective, as resistance has increased, perhaps due to the often long-term periods which are necessary for resolution and the accompanying tendency towards chronicity. In order to address the need for efficient alternative treatments, LMesitran ® Soft, a medical grade honey gel was used to treat 15 dogs with otitis externa of bacterial and/or fungal involvement. Success was based on clinical score decrease, cytology and owner input over time and with basis on culture results. 70% of enrolled dogs achieved clinical cure between days 7 to 14 and over 90% on day 21, the maximum established time limit, with a confidence interval of 95%. Furthermore, by day 7, 20% of dogs had obtained both clinical and cytological cures. This study was successfully able to demonstrate that the use of L-Mesitran® was effective in managing otitis externa in dogs, including cases in which highly resistant pathogens were present, such as methicillinresistant Staphylococcus pseudintermedius (MRSP), thus paving the way to future studies.ABSTRACT - L-MESITRAN® NO MANEIO DE OTITE EXTERNA CANINA – UM ESTUDO PILOTO - Numa altura em que nos deparamos com um aumento de bactérias com resistências aos antibióticos e em que os organismos envolvidos apresentam por vezes inclusivamente potencial zoonótico, o recurso ao mel e seus derivados pode ser uma inestimável ferramenta no decurso desta batalha. A otite externa em cães é um estímulo iatrotrópico frequente e das principais causas de idas ao médico veterinário. Alguns dos tratamentos habitualmente utilizados deixaram de ser eficazes à medida que as resistências surgiram, talvez consequência de terapêuticas prolongadas e recorrentes. Neste estudo avaliou-se uma potencial alternativa à terapêutica, recorrendo-se ao L-Mesitran® Soft, uma pomada contendo mel de grau clínico, para tratar 15 cães com otite externa de envolvimento bacteriano e/ou fúngico. A resposta foi considerada positiva de acordo com a diminuição da pontuação clínica, citologia e opinião dos donos, no decorrer do tempo. Estabelecido o limite de 21 dias, 70% dos cães tratados obteve cura clínica entre os dias 7 e 14 e mais de 90% no dia 21, com um intervalo de confiança de 95%. Ainda, até ao dia 7, 20% dos cães havia obtido cura clínica e citológica. Este estudo demonstrou que o L-Mesitran® foi eficaz no maneio dos casos de otite externa, incluindo aqueles em que estavam presentes bactérias com várias resistências aos antibióticos, como é o caso do Staphylococcus pseudintermedius com resistência à meticilina (SPRM), abrindo assim caminho para futuros estudos

Making Radiomics More Reproducible across Scanner and Imaging Protocol Variations: A Review of Harmonization Methods

Radiomics converts medical images into mineable data via a high-throughput extraction of quantitative features used for clinical decision support. However, these radiomic features are susceptible to variation across scanners, acquisition protocols, and reconstruction settings. Various investigations have assessed the reproducibility and validation of radiomic features across these discrepancies. In this narrative review, we combine systematic keyword searches with prior domain knowledge to discuss various harmonization solutions to make the radiomic features more reproducible across various scanners and protocol settings. Different harmonization solutions are discussed and divided into two main categories: image domain and feature domain. The image domain category comprises methods such as the standardization of image acquisition, post-processing of raw sensor-level image data, data augmentation techniques, and style transfer. The feature domain category consists of methods such as the identification of reproducible features and normalization techniques such as statistical normalization, intensity harmonization, ComBat and its derivatives, and normalization using deep learning. We also reflect upon the importance of deep learning solutions for addressing variability across multi-centric radiomic studies especially using generative adversarial networks (GANs), neural style transfer (NST) techniques, or a combination of both. We cover a broader range of methods especially GANs and NST methods in more detail than previous reviews

VIBRATIONAL SPECTROSCOPY FOR THE ASSESSMENT OF VULVAL DISEASE

Vibrational spectroscopic diagnostic techniques have significant potential to improve the care of women with benign, premalignant and malignant vulval diseases by reducing the reliance on traditional biopsy and histopathology. These techniques also have the potential to augment clinicians’ ability to differentiate different types of vulval disease at the time of surgery for neoplastic vulval disease. In addition, vibrational spectroscopic techniques offer the opportunity to assess molecular changes associated with the development of vulval cancer that are not apparent on routine histopathological assessment. The work outlined in this thesis evaluates the role of emerging techniques in vibrational spectroscopy to address this need within three key themes: 1. Developmentofavibrationalspectroscopicdiagnostictechniquetoreducethe reliance on traditional biopsy and histopathological diagnosis. 2. Developmentofavibrationalspectroscopicdiagnostictechniqueforimproving the delineation of disease margins at the time of surgery for pre-malignant and malignant vulval conditions. 3. Evaluation of a vibrational spectroscopic tool for augmenting and automating aspects of vulval histopathology. Raman spectroscopic mapping of 91 fresh frozen vulval tissue sections combined with multivariate spectral analysis was used to demonstrate that malignant vulval disease could be differentiated from non-neoplastic and premalignant vulval disease with a sensitivity of 97% and specificity of 78%. The technique was then tested in experimental conditions closer to in-vivo application, measuring spectra from 91 whole fresh frozen tissue blocks using microscope and probe Raman systems. This demonstrated the technique could differentiate malignant from non-neoplastic and premalignant vulval disease with sensitivities of 84% to 92% and specificities of 84% to 64% respectively. In a separate investigation vulval tissue blocks from 27 women with suspected lichen sclerosus underwent Raman spectroscopic point measurements. Multivariate analysis demonstrated Raman spectroscopy could be used to differentiate lichen sclerosus from other vulval disorders with a similar clinical appearance with a sensitivity of sensitivity of 91% and specificity of 80%. Fourier transform infrared (FTIR) spectroscopic mapping of 93 fixed paraffin embedded tissue sections was used to demonstrate that malignant vulval disease could be differentiated from non-neoplastic and premalignant with vulval disease with an approximate sensitivity of 100% and specificity of 79%. In addition FTIR spectroscopy was used to differentiate molecular changes in vulval intraepithelial neoplasia (VIN) and lichen sclerosus (LS) found in association with vulval squamous cell carcinoma (SCC). Analysis of FTIR spectroscopic tissue maps from 48 patients demonstrated the technique could differentiate LS associated with SCC with a sensitivity of approximately 100% and specificity of 84% and VIN associated with SCC with a sensitivity of approximately 100% and specificity 58%. This thesis demonstrates the considerable potential of vibrational spectroscopy in this clinical setting. The research has made significant progress in each of the three themes outlined above and indicates that further work is warranted to develop the techniques towards routine clinical application

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

The development and validation of the Virtual Tissue Matrix, a software application that facilitates the review of tissue microarrays on line

BACKGROUND: The Tissue Microarray (TMA) facilitates high-throughput analysis of hundreds of tissue specimens simultaneously. However, bottlenecks in the storage and manipulation of the data generated from TMA reviews have become apparent. A number of software applications have been developed to assist in image and data management; however no solution currently facilitates the easy online review, scoring and subsequent storage of images and data associated with TMA experimentation. RESULTS: This paper describes the design, development and validation of the Virtual Tissue Matrix (VTM). Through an intuitive HTML driven user interface, the VTM provides digital/virtual slide based images of each TMA core and a means to record observations on each TMA spot. Data generated from a TMA review is stored in an associated relational database, which facilitates the use of flexible scoring forms. The system allows multiple users to record their interpretation of each TMA spot for any parameters assessed. Images generated for the VTM were captured using a standard background lighting intensity and corrective algorithms were applied to each image to eliminate any background lighting hue inconsistencies or vignetting. Validation of the VTM involved examination of inter-and intra-observer variability between microscope and digital TMA reviews. Six bladder TMAs were immunohistochemically stained for E-Cadherin, β-Catenin and PhosphoMet and were assessed by two reviewers for the amount of core and tumour present, the amount and intensity of membrane, cytoplasmic and nuclear staining. CONCLUSION: Results show that digital VTM images are representative of the original tissue viewed with a microscope. There were equivalent levels of inter-and intra-observer agreement for five out of the eight parameters assessed. Results also suggest that digital reviews may correct potential problems experienced when reviewing TMAs using a microscope, for example, removal of background lighting variance and tint, and potential disorientation of the reviewer, which may have resulted in the discrepancies evident in the remaining three parameters

Towards an epistemology of medical imaging

Tese de doutoramento (co-tutela), História e Filosofia das Ciências (Filosofia), Faculdade de Ciências da Universidade de Lisboa, Università degli Studi di Milano, 201