Supervised vessel delineation in retinal fundus images with the automatic selection of B-COSFIRE filters

The inspection of retinal fundus images allows medical doctors to diagnose various pathologies. Computer-aided diagnosis systems can be used to assist in this process. As a first step, such systems delineate the vessel tree from the background. We propose a method for the delineation of blood vessels in retinal images that is effective for vessels of different thickness. In the proposed method, we employ a set of B-COSFIRE filters selective for vessels and vesselendings. Such a set is determined in an automatic selection process and can adapt to different applications. We compare the performance of different selection methods based upon machine learning and information theory. The results that we achieve by performing experiments on two public benchmark data sets, namely DRIVE and STARE, demonstrate the effectiveness of the proposed approach

Vessels delineation in retinal images using COSFIRE filters

Retinal image analysis is widely used in the medical community to diagnose several pathologies. The automatic analysis of such images is important to perform more ef-ficient diagnosis. We propose an effective method for the delineation of blood vessels in retinal images using train-able bar-selective COSFIRE filters. The results that we achieve on three publicly available data sets (DRIVE: Se = 0.7655, Sp = 0.9704; STARE: Se = 0.7763, Sp = 0.9695; CHASE DB1: Se = 0.7699, Sp = 0.9476) demonstrate the effectiveness of the proposed approach.peer-reviewe

Count Saverio Marchese (1757-1833) : his picture-gallery and his bequest to the Cathedral Museum

Picture collecting in Malta as elsewhere was the favourite pastime of the Knights, the nobility, wealthy people and a few scholars and art lovers centuries ago. Local and foreign artists commissioned to decorate our churches and palaces were also asked to decorate private houses and furnish them with portraits and other paintings. Inventories of the many art collections in private houses may have been compiled by their respective owners in their own lifetime but they were certainly compiled in the interests of heirs and claimants immediately after their death. An important art collection in the early 19th century was that of Count Saverio Marchese, fourth son of Cavaliere Giuseppe Isidoro and Serafina Marmier. Of all the old collectors Saverio Marchese was one of the earliest, to my knowledge, to have left his collection of paintings, drawings, prints and art books as a legacy to a public institution — the Cathedral Church.peer-reviewe

ClearPath: a new method for fast and simple drainage of a perianastomotic abscess

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Endoscopic treatment of an infected retroperitoneal hematoma following endoscopic ultrasound-guided pseudocyst drainage

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Quality of communication between dentists and dental laboratory technicians in Malta

Abstract: Purpose. The purpose of this study was to assess the quality of communication between the dental clinic and dental laboratory from a dental laboratory technicians’ point of view and to offer means for improving communication between these two workplaces. Methods and Materials. This pilot study was carried out on 38 dental laboratory technicians comprising of 14 dental laboratory technicians from the Dental Laboratory –Dental Department, Mater Dei Hospital along with 24 dental laboratory technicians from private dental laboratories spread across the Maltese Islands. The study used binomial tests as the form for inferential analysis of results with the reference level of significance set up to 5%( = 0:05) whereby a percentage of 75% was viewed as being significantly disparate from p = 50% with 84.6% of statistical power, assuming a 95% level of confidence. The collection of data was taken through the use of a questionnaire issued on a one-time basis. Results. The study reported 65.6% of dental technicians received impressions in a non-disinfected state (p = 0:110). 40.6% of dental technicians found the written dental clinic prescription card instructions as ‘Good’ (p = 0:001**) whilst 46.9% ‘Occasionally’ interact with their dental patients (p = 0:215). 31.3% of dental technicians view themselves as ‘Important-Very important’ (p = 0:302). The majority of dental technicians are comfortable discussing prosthesis design with dentists (87.5%) (p<= 0:001***). Conclusion. Communication between the dental clinic and dental laboratory was found to possess several strengths and weaknesses in the eyes of Maltese dental technicians. There is room for improvement in communication between these two dental workplaces.peer-reviewe

Unsupervised delineation of the vessel tree in retinal fundus images

Retinal imaging has gained particular popularity as it provides an opportunity to diagnose various medical pathologies in a non-invasive way. One of the basic and very important steps in the analysis of such images is the delineation of the vessel tree from the background. Such segmentation facilitates the investigation of the morphological characteristics of the vessel tree and the analysis of any lesions in the background, which are both indicators for various pathologies. We propose a novel method called B-COSFIRE for the delineation of the vessel tree. It is based on the classic COSFIRE approach, which is a trainable nonlinear filtering method. The responses of a B-COSFIRE filter is achieved by combining the responses of difference-of-Gaussians filters whose areas of support are determined in an automatic configuration step. We configure two types of B-COSFIRE filters, one that responds selectively along vessels and another that is selective to vessel endings. The segmentation of the vessel tree is achieved by summing up the response maps of both types of filters followed by thresholding.We demonstrate high effectiveness of the proposed approach by performing experiments on four public data sets, namely DRIVE, STARE, CHASE DB1 and HRF. The delineation approach that we propose also has lower time complexity than existing methods.peer-reviewe

HST observations of the Local Group dwarf galaxy Leo I

We present deep HST F555W (V) and F814W (I) observations of a central field in the Local Group dwarf spheroidal (dSph) galaxy Leo I. The resulting color-magnitude diagram (CMD) reaches I \simeq 26 and reveals the oldest ~10-15 Gyr old turnoffs. Nevertheless, a horizontal branch is not obvious in the CMD. Given the low metallicity of the galaxy, this likely indicates that the first substantial star formation in the galaxy may have been somehow delayed in Leo I in comparison with the other dSph satellites of the Milky Way. The subgiant region is well and uniformly populated from the oldest turnoffs up to the 1 Gyr old turnoff, indicating that star formation has proceeded in a continuous way, with possible variations in intensity but no big gaps between successive bursts, over the galaxy's lifetime. The structure of the red-clump of core He-burning stars is consistent with the large amount of intermediate-age population inferred from the main sequence and the subgiant region. In spite of the lack of gas in Leo I, the CMD clearly shows star formation continuing until 1 Gyr ago and possibly until a few hundred Myrs ago in the central part of the galaxy.Comment: 26 pages with 8 figures (fig 2 not available electronically). To be published in ApJ, April 1 1999 (vol.514, #2

Multiscale blood vessel delineation using B-COSFIRE filters

We propose a delineation algorithm that deals with bar-like structures of different thickness. Detection of linear structures is applicable to several fields ranging from medical images for segmentation of vessels to aerial images for delineation of roads or rivers. The proposed method is suited for any delineation problem and employs a set of B-COSFIRE filters selective for lines and line-endings of different thickness. We determine the most effective filters for the application at hand by Generalized Matrix Learning Vector Quantization (GMLVQ) algorithm. We demonstrate the effectiveness of the proposed method by applying it to the task of vessel segmentation in retinal images. We perform experiments on two benchmark data sets, namely DRIVE and STARE. The experimental results show that the proposed delineation algorithm is highly effective and efficient. It can be considered as a general framework for a delineation task in various applications.peer-reviewe