ScarGAN: Chained Generative Adversarial Networks to Simulate Pathological Tissue on Cardiovascular MR Scans

Medical images with specific pathologies are scarce, but a large amount of data is usually required for a deep convolutional neural network (DCNN) to achieve good accuracy. We consider the problem of segmenting the left ventricular (LV) myocardium on late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) scans of which only some of the scans have scar tissue. We propose ScarGAN to simulate scar tissue on healthy myocardium using chained generative adversarial networks (GAN). Our novel approach factorizes the simulation process into 3 steps: 1) a mask generator to simulate the shape of the scar tissue; 2) a domain-specific heuristic to produce the initial simulated scar tissue from the simulated shape; 3) a refining generator to add details to the simulated scar tissue. Unlike other approaches that generate samples from scratch, we simulate scar tissue on normal scans resulting in highly realistic samples. We show that experienced radiologists are unable to distinguish between real and simulated scar tissue. Training a U-Net with additional scans with scar tissue simulated by ScarGAN increases the percentage of scar pixels correctly included in LV myocardium prediction from 75.9% to 80.5%.Comment: 12 pages, 5 figures. To appear in MICCAI DLMIA 201

Experimental phase-space-based optical amplification of scar modes

Waves billiard which are chaotic in the geometrical limit are known to support non-generic spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in micro-cavity lasers and vertically-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in their wave analogous phase space representation, we report experimental results of scar modes selection by gain in a doped D-shaped optical fiber

Variation in the impact of stem scar and cuticle on water loss in highbush blueberry fruit argue for the use of water permeance as a selection criterion in breeding

The role of fruit scar on water loss from fresh harvested, fully blue highbush blueberry (Vaccinium corymbosum L.) fruit was studied on three germplasm lines from each of three half-sib families at University of Talca, Chile. The stem scar of half of the harvested fruit was sealed using nail polish and weight loss of sealed and non-sealed fruit determined daily at 20 °C (5 d storage) and bi-weekly at 0 °C (15 d storage). Fruit firmness was determined at the end of the storage period. The stem scar accounted for approximately 40% of the moisture lost at 20 °C, but percentages varied considerably between lines. While the stem scar covered 0.19% to 0.74% of the fruit surface area, its rate of transpiration was 170-times higher than for the cuticle at 20 °C. The larger the fruit scar area, the greater was the absolute rate of water loss, but scar size scar did not affect the rate of weight loss expressed on a per gram fruit basis. Higher levels of water loss were associated with a greater loss in firmness; fruit having a large scar had a greater rate of water loss and were less firm than those having medium or small scars. The water permeance of the fruit cuticle varied two-fold and the apparent permeance of the scar varied three-fold among the 9 lines evaluated when held at 20 °C. Interestingly, one line exhibited a 75% lower rate of water loss from its stem scar than the other lines than would be predicted based on its scar diameter. Storage at 0 °C reduced the rate of water loss by 90% but the cuticle permeance was not affected by temperature. Sealing the stem scar increased fruit firmness retention at 0 °C and 20 °C, but provided less benefit at 0 °C vs. 20 °C. The highly variable nature of water loss through the stem scar and the cuticle in this study suggests that large gains in reductions in water loss are possible for the highbush blueberry once the mechanisms for transpiration are better understood.In Chile, this work was supported by the National Commission for Scientific and Technological ResearchCONICYT (FONDECYT11130539) and the Universidad de Talca (research programs “Adaptation of Agriculture to Climate Change (A2C2)”, “Fondo Proyectos de Investigación” and “Núcleo Científico Multidisciplinario”). In the United States this work was partially supported by the “2015 Fulbright Specialist Program”, Project 6365. In Spain this work was partially supported by “Fundación Carolina” and “Programa de Doctorado en Ciencia y Tecnología Agraria y Alimentaria”, Universitat de Lleida

Selective amplification of scars in a chaotic optical fiber

In this letter we propose an original mechanism to select scar modes through coherent gain amplification in a multimode D-shaped fiber. More precisely, we numerically demonstrate how scar modes can be amplified by positioning a gain region in the vicinity of specific points of a short periodic orbit known to give rise to scar modes

The correlation between histopathological and ultrasound findings regarding Cesarean section scars – A three-year survey study

The cesarean operation represents a major surgery, with a higher risk of postoperative complications and longer postoperative recovery than vaginal delivery. Due to the increasing frequency of cesarean sections, the ultrasound imaging of the uterine scar has become a particularly useful tool in identifying its potential long-term complications. This should be done pre-conceptively and quarterly or whenever necessary during pregnancy. Currently, there are only few histopathological studies on the uterine scar, trying to assess the myometrial repair and certain factors that influence the quality of the scar. The study was performed on a batch of 123 patients with previous C-sections, with multiple ultrasound exams during pregnancy and post-operative pathologic evaluation of the uterine scar in order to assess the possibility of a new prognostic score by correlating these two factors. Our study found solid evidence related to possible correlations between histopathological and ultrasound data on the cesarean section scar, which could lead to a possible predictive algorithm with implications for both prognostic and therapeutic fields

Albrecht Durer and the Lutheran Reformation

This dissertation is a study of Albrecht Dürer\u27s life and work with a theologioa1 interest. This is in no way a complete discussion of the artist\u27s life and works. The selection of works treated in chapter four is not a good cross section of his drawings, woodcuts. copper engravings, etchings, and paintings. They are a careful selection of his works of art showing how he gradually employed true Christian or Biblical teaching in his religious subjects. The author endeavors to show in this paper that Albrecht Dürer made a contribution to the work of Martin Luther and his associates as a preparatory figure to the reform movement and how later the work of Martin Luther influenced the great German artist