An Objective Scatter Index Based on Double-Pass Retinal Images of a Point Source to Classify Cataracts

PURPOSE: To propose a new objective scatter index (OSI) based in the analysis of double-pass images of a point source to rank and classify cataract patients. This classification scheme is compared with a current subjective system. METHODS: We selected a population including a group of normal young eyes as control and patients diagnosed with cataract (grades NO2, NO3 and NO4) according to the Lens Opacities Classification System (LOCS III). For each eye, we recorded double-pass retinal images of a point source. In each patient, we determined an objective scatter index (OSI) as the ratio of the intensity at an eccentric location in the image and the central part. This index provides information on the relevant forward scatter affecting vision. Since the double-pass retinal images are affected by both ocular aberrations and intraocular scattering, an analysis was performed to show the ranges of contributions of aberrations to the OSI. RESULTS: We used the OSI values to classify each eye according to the degree of scatter. The young normal eyes of the control group had OSI values below 1, while the OSI for subjects in LOCS grade II were around 1 to 2. The use of the objective index showed some of the weakness of subjective classification schemes. In particular, several subjects initially classified independently as grade NO2 or NO3 had similar OSI values, and in some cases even higher than subjects classified as grade NO4. A new classification scheme based in OSI is proposed. CONCLUSIONS: We introduced an objective index based in the analysis of double-pass retinal images to classify cataract patients. The method is robust and fully based in objective measurements; i.e., not depending on subjective decisions. This procedure could be used in combination with standard current methods to improve cataract patient surgery scheduling

Usefulness of bronchoalveolar lavage in suspect COVID-19 repeatedly negative swab test and interstitial lung disease

The diagnosis of coronavirus disease 2019 (COVID-19) relies on nasopharyngeal swab, which shows a 20–30% risk of false negativity [1]. Bronchoalveolar lavage (BAL) is reported to be useful in patients with pulmonary interstitial infiltrates on high-resolution computed tomography (HRCT). We investigated the usefulness of BAL in symptomatic patients with positive HRCT and a repeatedly negative swab test (‘grey zone’)

Computer-aided assessment of diagnostic images for epidemiological research

<p>Abstract</p> <p>Background</p> <p>Diagnostic images are often assessed for clinical outcomes using subjective methods, which are limited by the skill of the reviewer. Computer-aided diagnosis (CAD) algorithms that assist reviewers in their decisions concerning outcomes have been developed to increase sensitivity and specificity in the clinical setting. However, these systems have not been well utilized in research settings to improve the measurement of clinical endpoints. Reductions in bias through their use could have important implications for etiologic research.</p> <p>Methods</p> <p>Using the example of cortical cataract detection, we developed an algorithm for assisting a reviewer in evaluating digital images for the presence and severity of lesions. Available image processing and statistical methods that were easily implementable were used as the basis for the CAD algorithm. The performance of the system was compared to the subjective assessment of five reviewers using 60 simulated images. Cortical cataract severity scores from 0 to 16 were assigned to the images by the reviewers and the CAD system, with each image assessed twice to obtain a measure of variability. Image characteristics that affected reviewer bias were also assessed by systematically varying the appearance of the simulated images.</p> <p>Results</p> <p>The algorithm yielded severity scores with smaller bias on images where cataract severity was mild to moderate (approximately ≤ 6/16^<it>ths</it>). On high severity images, the bias of the CAD system exceeded that of the reviewers. The variability of the CAD system was zero on repeated images but ranged from 0.48 to 1.22 for the reviewers. The direction and magnitude of the bias exhibited by the reviewers was a function of the number of cataract opacities, the shape and the contrast of the lesions in the simulated images.</p> <p>Conclusion</p> <p>CAD systems are feasible to implement with available software and can be valuable when medical images contain exposure or outcome information for etiologic research. Our results indicate that such systems have the potential to decrease bias and discriminate very small changes in disease severity. Simulated images are a tool that can be used to assess performance of a CAD system when a gold standard is not available.</p

Transfer of chemicals to a secondary container, from the introduction of new labelling regulation to COVID-19 lockdown: a retrospective analysis of exposure calls to the Poison Control Centre of Rome, Italy, 2017–2020

The transfer of a chemical product from its original container to an unlabelled secondary container by consumers is a potential health hazard that may result in unintentional exposures and intoxications. The aim of this study was to describe the pattern of prevalence of exposures to transferred products in Italy from year 2017, when the new European labelling regulation for chemicals became fully operative, to 2020, year of the coronavirus 19 disease first outbreak. Calls to the Poison Control Centre (PCC) of Policlinico Umberto I Hospital - Sapienza University of Rome were analysed retrospectively for characteristics, clinical presentation and circumstances related to the event. We registered 198 cases of interest. There was a reduction in cases from 2017 (4.9%) to 2019 (2.2%), followed by an increased prevalence in 2020 (4.2%) mainly due to the months “post-lockdown.” The transferred product was very frequently diluted, and an empty drinking bottle was usually used as secondary container. Exposures were mostly of minor severity, and no deaths occurred. The study highlights the importance of PCCs data in the evaluation of the hazard communication to users through labels and advises for public campaigns to promote safe behaviours during future lockdowns to prevent exposures at a later period

Detection of leukotrienes B4, C4, and of their isomers in arterial, mixed venous blood and bronchoalveolar lavage fluid from ARDS patients.

Seven patients with the adult respiratory distress syndrome (ARDS) were studied. As a control group we used 6 surgical patients who underwent minor surgical operation (inguinal hernia). For both groups the same sample collection and analysis was used. The presence of leuktorienes (LTs) B4 and C4 and of their isomers 11-trans LTC4 and delta 6-trans-12-epi LTB4 was determined in arterial, mixed venous blood and in bronchoalveolar lavage (BAL) fluid. The samples, analysed by reverse phase high performance liquid chromatography (RP-HPLC), showed a similar chromatographic picture among ARDS patients, while the control group showed no detectable amounts of LTs in BAL or blood. The distribution of these arachidonic acid metabolites in mixed venous blood, arterial blood and BAL seems to suggest pulmonary metabolism and/or inactivation. It is suggested that these mediators act as humoral factors in pathogenesis of the ARDS