SAR Image Edge Detection: Review and Benchmark Experiments

Edges are distinct geometric features crucial to higher level object detection and recognition in remote-sensing processing, which is a key for surveillance and gathering up-to-date geospatial intelligence. Synthetic aperture radar (SAR) is a powerful form of remote-sensing. However, edge detectors designed for optical images tend to have low performance on SAR images due to the presence of the strong speckle noise-causing false-positives (type I errors). Therefore, many researchers have proposed edge detectors that are tailored to deal with the SAR image characteristics specifically. Although these edge detectors might achieve effective results on their own evaluations, the comparisons tend to include a very limited number of (simulated) SAR images. As a result, the generalized performance of the proposed methods is not truly reflected, as real-world patterns are much more complex and diverse. From this emerges another problem, namely, a quantitative benchmark is missing in the field. Hence, it is not currently possible to fairly evaluate any edge detection method for SAR images. Thus, in this paper, we aim to close the aforementioned gaps by providing an extensive experimental evaluation for SAR images on edge detection. To that end, we propose the first benchmark on SAR image edge detection methods established by evaluating various freely available methods, including methods that are considered to be the state of the art

Successful multiple segment coronary angioplasty: Effect of completeness of revascularization in single-vessel multilesions and multivessels

A long-term follow-up study was performed to evaluate the long-term value of performing multiple dilatations according to their procedural (single-vessel multilesion or mutltivessel dilatations) and anatomic types (single-vessel disease with multiple dilatations or multivessel disease dilatations with complete and incomplete revascularization). From 1980 until 1988, 248 patients met the following criteria: (1) at least two lesions dilated (range: 2 to 4) and (2) all attempted lesions successfully dilated. The mean length of follow-up was 33 months. The end points analyzed were death, myocardial infarction, redilatation, and bypass surgery. No differences were found for these events between the single-vessel multilesion group (144 patients) and the multivessel group (104 patients). The 4.5-year probability of event-free survival was 68% and 70%, respectively, for the multilesion group and the multivessel group. In the event-free patients, 57% versus 59% were asymptomatic and 45% versus 46% were not taking antianginal drugs. In the anatomic subgroups, there were less event-free patients in the cohort of incompletely revascularized multivessel disease patients (55% of 55 patients) when compared with the cohort of those who were completely revascularized (84% of 79 patients) or when compared with the single-vessel disease multiple dilatation patients (74% of 107 patients). The 4.5-year event-free survival probability for each group was 44%, 78%, and 74%, respectively. This difference was caused by more infarctions (9% versus 2% versus 4%, respectively) and bypass operations in the multivessel disease, incomplete revascularization group (20% versus 5% versus 10%, respectively). In event-free patients, improvement of angina was similar and was documented in over 85% of patients in each group. Furthermore, the number of asymptomatic patients at follow-up was similar in all groups except that within the incomplete revascularization group, less patients were free of antianginal drugs (21% versus 51% versus 48%). Finally, 48% of the entire cohort performed an exercise test 4.6 months (mean) after dilatation and no difference was found in any of the variables in any group. About 10% of the patients experienced angina and approximately 30% had a positive exercise test for ischemia by ST segment criteria. The functional performance in every group was over 90% of the predicted work load. These results suggest that completeness of revascularization in multivessel disease patients is an important prognostic variable. However, the symptomatic improvement after dilatation is very rewarding in all subsets of patients and argues in favor of the continued use of multiple dilatations as a treatment strategy

Left Main Coronary Angioplasty: Assessment of a “Risk Score” to Predict Acute and Long‐Term Outcome

Due to the recent emergence of adjunctive techniques such as cardiopulmonary bypass support, left main angioplasty may become more routinely applied in the near future. In order to choose the best possible therapy, a precise risk assessment will be desirable. Twenty‐two left main angioplasties were thus re

Long-term follow-up after attempted angioplasty of saphenous vein grafts: the Thoraxcenter experience 1981-1988

Between 1981 and 1988, 107 percutaneous transluminal coronary angioplasty (PTCA) procedures, including repeat PTCA, were performed in 84 patients with previous coronary artery bypass grafting (CABG). Fifty-nine patients underwent a first angioplasty of the vein graft alone, and 25 underwent a first PTCA of the graft and one or more native vessels. Seventeen patients underwent two procedures, four patients three procedures and one patient four procedures. In 84 first angioplasties, 133 lesions were attempted; 40 lesions in native vessels and 93 graft lesions (28 ostial stenoses, 33 shaft stenoses, and 32 stenoses at the distal anastomosis). Three patients died during their hospital stay. Two patients underwent emergency CABG. Seven patients sustained an acute myocardial infarction (AMI), among whom five underwent a PTCA of an occluded vessel. The clinical primary success rate per patient was 82%. After five years, 70% of patients were alive. At a median follow-up of 2.1 years, 41% of patients were alive and event-free (no AMI, no repeat CABG, no repeat PTCA). Symptomatic improvement was maintained in 36% of patients. Angioplasty of grafts may be an alternative to re-operation in selected patients with previous bypass surgery

Model-consistent estimation of the basic reproduction number from the incidence of an emerging infection

We investigate the merit of deriving an estimate of the basic reproduction number \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} early in an outbreak of an (emerging) infection from estimates of the incidence and generation interval only. We compare such estimates of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} with estimates incorporating additional model assumptions, and determine the circumstances under which the different estimates are consistent. We show that one has to be careful when using observed exponential growth rates to derive an estimate of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\mathcal{R}_0$$ \end{document} , and we quantify the discrepancies that arise

The Vega debris disc: A view from Herschel

We present five band imaging of the Vega debris disc obtained using the Herschel Space Observatory. These data span a wavelength range of 70-500 mu m with full-width half-maximum angular resolutions of 5.6-36.9 ''. The disc is well resolved in all bands, with the ring structure visible at 70 and 160 mu m. Radial profiles of the disc surface brightness are produced, and a disc radius of 11 '' (similar to 85AU) is determined. The disc is seen to have a smooth structure thoughout the entire wavelength range, suggesting that the disc is in a steady state, rather than being an ephemeral structure caused by the recent collision of two large planetesimals

Defining inclusion criteria and endpoints for clinical trials: a prospective cross-sectional study in CRB1-associated retinal dystrophies

Purpose: To investigate the retinal structure and function in patients with CRB1-associated retinal dystrophies (RD) and to explore potential clinical endpoints. Methods: In this prospective cross-sectional study, 22 patients with genetically confirmed CRB1-RD (aged 6–74 years), and who had a decimal best-corrected visual acuit

The spectrum of structural and functional abnormalities in female carriers of pathogenic variants in the RPGR gene

PURPOSE. The purpose of this study was to investigate the phenotype and long-term clinical course of female carriers of RPGR mutations. METHODS. This was a retrospective cohort study of 125 heterozygous RPGR mutation carriers from 49 families. RESULTS. Eighty-three heterozygotes were from retinitis pigmentosa (RP) pedigrees, 37 were from cone-/cone-rod dystrophy (COD/CORD) pedigrees, and 5 heterozygotes were from pedigrees with mixed RP/CORD or unknown diagnosis. Mutations were located in exon 1-14 and in ORF15 in 42 of 125 (34%) and 83 of 125 (66%) subjects, respectively. The mean age at the first examination was 34.4 years (range, 2.1 to 86.0 years). The median follow-up time in heterozygotes with longitudinal data (n = 62) was 12.2 years (range, 1.1 to 52.2 years). Retinal pigmentary changes were present in 73 (58%) individuals. Visual symptoms were reported in 51 (40%) cases. Subjects with both symptoms and pigmentary fundus changes were older than the other heterozygotes (P = 0.01) and had thinner foveal outer retinas (P = 0.006). Complete expression of the RP or CORD phenotype was observed in 29 (23%) heterozygotes, although usually in milder forms than in affected male relatives. Best-corrected visual acuity (BCVA) was <20/40 and <20/400 in at least one eye in 45 of 116 (39%) and 11 of 116 (9%) heterozygotes, respectively. Myopia was observed in 74 of 101 (73%) subjects and was associated with lower BCVA (P = 0.006). Increasing age was associated with lower BCVA (P = 0.002) and decreasing visual field size (P = 0.012; I4e isopter). CONCLUSIONS. RPGR mutations lead to a phenotypic spectrum in female carriers, with myopia as a significantly aggravating factor. Complete disease expression is observed in some individuals, who may benefit from future (gene) therapeutic options

Ophthalmology

OBJECTIVE: In the current study we aimed to identify metabolites associated with age-related macular degeneration (AMD) by performing the largest metabolome association analysis in AMD to date. In addition, we aimed to determine the effect of AMD-associated genetic variants on metabolite levels, and aimed to investigate associations between the identified metabolites and activity of the complement system, one of the main AMD-associated disease pathways. DESIGN: Case-control assocation analysis of metabolomics data. SUBJECTS: 2,267 AMD cases and 4,266 controls from five European cohorts. METHODS: Metabolomics was performed using a high-throughput H-NMR metabolomics platform, which allows the quantification of 146 metabolite measurements and 79 derivative values. Metabolome-AMD associations were studied using univariate logistic regression analyses. The effect of 52 AMD-associated genetic variants on the identified metabolites was investigated using linear regression. In addition, associations between the identified metabolites and activity of the complement pathway (defined by the C3d/C3 ratio) were investigated using linear regression. MAIN OUTCOME MEASURES: Metabolites associated with AMD RESULTS: We identified 60 metabolites that were significantly associated with AMD, including increased levels of large and extra-large HDL subclasses and decreased levels of VLDL, amino acids and citrate. Out of 52 AMD-associated genetic variants, seven variants were significantly associated with 34 of the identified metabolites. The strongest associations were identified for genetic variants located in or near genes involved in lipid metabolism (ABCA1, CETP, APOE, LIPC) with metabolites belonging to the large and extra-large HDL subclasses. In addition, 57 out of 60 metabolites were significantly associated with complement activation levels, and these associations were independent of AMD status. Increased large and extra-large HDL levels and decreased VLDL and amino acid levels were associated with increased complement activation. CONCLUSIONS: Lipoprotein levels were associated with AMD-associated genetic variants, while decreased essential amino acids may point to nutritional deficiencies in AMD. We observed strong associations between the vast majority of the AMD-associated metabolites and systemic complement activation levels, independent of AMD status. This may indicate biological interactions between the main AMD disease pathways, and suggests that multiple pathways may need to be targeted simultaneously for successful treatment of AMD