Skin Lesion Diagnosis

Pre-screening systems for the diagnosis of melanocytic skin lesions depend of the proper segmentation of the image region affected by the lesion. This paper proposes a feature learning scheme that finds relevant features for skin lesion image segmentation. This work introduces a new unsupervised dictionary learning method, namely Unsupervised Information-Theoretic Dictionary Learning (UITDL), and discusses how it can be applied in the segmentation of skin le-sions in macroscopic images. The UITDL approach is adaptive and tends to be robust to outliers in the training data, and consists of two main stages. In the first stage, a textural variation image is used to construct an initial feature dictionary and an initial sparse representation via Non-Negative Matrix Fac-torization (NMF). In the second stage, the feature dictionary is optimized by selecting adaptively the number of dictionary atoms. The greedy approach used for dictionary optimization is quite efficient and flexible enough to be applied to other dictionary learning problems. Furthermore, the proposed method can be easily extended for other image segmentation problems. The experimental results suggest that the proposed approach potentially can provide more accurate skin lesion segmentation results than comparable state-of-the-art methods. The proposed segmentation method could help to improve the performance of pre-screening systems for melanocytic skin lesions, which can affect positively the quality of the early diagnosis provided to skin lesion patients.

This paper shows that adding 3D depth information to RGB colour images improves segmentation of pigmented and non-pigmented skin lesion. A region-based active contour segmentation approach using a statistical model based on the level-set framework is presented. We consider what kinds of properties (e.g., colour, depth, texture) are most discriminative. The experiments show that our proposed method integrating chromatic and geometric information produces segmentation results for pigmented lesions close to dermatologists and more consistent and accurate results for non-pigmented lesions.

This paper gives an example of evolved features that improve image retrieval performance. A content-based image retrieval system for skin lesion images is presented. The aim is to support decision making by retrieving and displaying relevant past cases visually similar to the one under examination. Skin lesions of five common classes, including two non-melanoma cancer types, are used. Colour and texture features are extracted from lesions. Evolutionary algorithms are used to create composite features that optimise a similarity matching function. Experiments on our database of 533 images are performed and results are compared to those obtained using simple features. The use of the evolved composite features improves the precision by about 7%.

This paper presents a seed finding method for region growing segmentation approach using color channel energy in image regions. Instead of using the RGB system separated for each pixel, the proposal uses the energy on each color channel to improve the range of the possible values, then  creates a more specific seed to detail different regions. Region size used to calculate energy was adjusted to verify the proposed method. Images used were real wound photos, taken from patients undergoing treatment at the university hospital. Results showed that energy on regions presents enough information to segment, leading to a high percentage of matching with experts marks.

Keywords: Medical Computing, Image Segmentation, Skin
Lesion Recognition, Region Growing Algorithm Seed.

A tropical forest is a hostile environment for humans. The military physician supporting these immersion activities must cope with varied clinical situations with limited resources to reduce operational unavailability. This article reports a prospective cross-sectional epidemiologic study conducted from January to May 2012, observing the daily activity at sick call during the rainy season at the tropical forest training center (CEFE) advanced jungle commando training, located in French Guyana. The aim was to observe the distribution of traumatic injuries and specific diseases in this tropical environment. In all, 9,221 army staff members participated in the training (mean age: 30.8 years) during the 120-day study period. There were 486 medical visits, for a mean daily incidence of 5.3% (trainees: 83.8%, trainers: 16.5%). Skin lesions were most frequent (39%), principally irritative dermatitis and skin maceration (moisture/dressing associated dermatitis). A third (34%) of these conditions were due to trauma, mainly limb contusions and ligament injuries. Tropical diseases accounted for 3% of the reasons for consultation, with rare problems related to equatorial fauna or flora. The remaining conditions (24%) were not specific to the environment or activity. Operational attrition averaged five days. Removal from the training course was necessary in 13.8% of the cases. In an isolated area with a demanding environment , edical practice in a tropical forest requires health prevention actions and close medical follow-up. The permanent presence of a physician provides both care and expertise and is an important asset for both trainees and trainers.
La forêt équatoriale est un environnement hostile pour l’homme. Le médecin militaire soutenant des activités en immersion doit faire face à des situations cliniques variées avec des moyens limités pour réduire l’indisponibilité opérationnelle. Etude épidémiologique prospective transversale de janvier à mai 2012 observant, en saison des pluies, l’activité quotidienne de consultation médicale du Centre d’entrainement en forêt équatoriale (CEFE), pôle d’excellence dans l’aguerrissement commando en jungle situé en Guyane. Le but était d’observer la répartition des affections traumatiques et les pathologies spécifiques de l’environnement équatorial. Durant 120 jours, 9221 personnels ont été inclus (âge moyen de 30,8 ans ). Pour 486 consultations l’incidence moyenne des consultations était de 5,3% par jour (stagiaires : 83,8%, encadrement : 16,5%). Les lésions cutanées étaient majoritaires (39%), principalement des dermites irritatives et de macération. Un tiers (34%) des affections étaient traumatiques, en majorité des contusions et lésions ligamentaires des membres. Les maladies tropicales représentaient 3% des motifs de consultations avec de rares problèmes liées à la faune ou à la flore équatoriale. Le reste des affections (24%) étaient non spécifiques du milieu ou de l’activité. L’attrition opérationnelle était de 5 jours en moyenne . Un arrêt définitif de l’entrainement a été nécessaire dans 13,8% des cas. En milieu isolé, dans un environnement exigeant, l’exercice médical en forêt équatoriale impose des actions de prévention sanitaire et un suivi médical au plus près. Entre soins et expertise, la présence permanente du médecin est un véritable atout pour les stagiaires et l’encadrement.

An 8-year-old boy went in my private dental practice for a
control of a deciduous tooth. The child is in good general health
and the parents did not report any health problems. The deciduous
element in the right jawbone was extremely compromised and
with sharp edges that was creating small wounds in the patient’s
mouth. It was decided to carry out the avulsion of the element.
A mepivacaine anesthesia with 1: 100,000 adrenalines, in vials
of 1.8 cl was administrated. The local anesthesia was injected on
the alveolar mucosa near the deciduous element. The extraction
was performed with a straight lever within a few minutes. The
post-surgical wound was medicated with cotton rolls and after
15 minutes the patient was discharged. 12 hours later the parents
of the child called back to see the child who had a lesion on the
right cheek, the same where the avulsion was performed. The
patient showed an area of about 4.5 cm of larger diameter, abraded
and brown. The child reported a burning sensation. The alveolar
mucosa in the site of avulsion was in good condition, there were
no lymph node swelling, the post-extraction site was not painful.
The patient was not an allergic subject. A more detailed anamnestic
investigation showed that the child did not feel the right cheek
after anesthesia and had rubbed the back of his hand several
times on the cheek and without knowing it, had caused the skin
lesion. Application of Aloe vera gel 2 times a day for 7 days was
prescribed to reduce burning sensation and to improve the healing.