Assessment of treatment failure in endodontic therapy

There is a paucity of guidelines for the dental profession to assess failure of endodontic therapy. While a successful treatment can be well defined by the absence of apical periodontitis and clinical symptoms after a period of observation, failed treatment has escaped a distinct standing over the years. This article highlights aspects of significance and concludes that research ought to better explore the general health properties of persistent apical periodontitis on root‐filled teeth and finally confirm the extent there is an association between apical periodontitis and adverse systemic health effects. Clearing this condition will determine whether clinicians should take a serious or relaxed attitude to persistent apical periodontitis subsequent to endodontic treatment.     

Quantification of vessel-specific coronary perfusion territories using minimum-cost path assignment and computed tomography angiography: Validation in a swine model

BackgroundAs combined morphological and physiological assessment of coronary artery disease (CAD) is necessary to reliably resolve CAD severity, the objective of this study was to validate an automated minimum-cost path assignment (MCP) technique which enables accurate, vessel-specific assignment of the left (LCA) and right (RCA) coronary perfusion territories using computed tomography (CT) angiography data for both left and right ventricles.MethodsSix swine were used to validate the MCP technique. In each swine, a dynamic acquisition comprised of twenty consecutive volume scans was acquired with a 320-slice CT scanner following peripheral injection of contrast material. From this acquisition the MCP technique was used to automatically assign LCA and RCA perfusion territories for the left and right ventricles, independently. Each animal underwent another dynamic CT acquisition following direct injection of contrast material into the LCA or RCA. Using this acquisition, reference standard LCA and RCA perfusion territories were isolated from the myocardial blush. The accuracy of the MCP technique was evaluated by quantitatively comparing the MCP-derived LCA and RCA perfusion territories to these reference standard territories.ResultsAll MCP perfusion territory masses (Mass_MCP) and all reference standard perfusion territory masses (Mass_RS) in the left ventricle were related by Mass_MCP = 0.99Mass_RS+0.35 g (r = 1.00). Mass_MCP and Mass_RS in the right ventricle were related by Mass_MCP = 0.94Mass_RS+0.39 g (r = 0.96).ConclusionThe MCP technique was validated in a swine animal model and has the potential to be used for accurate, vessel-specific assignment of LCA and RCA perfusion territories in both the left and right ventricular myocardium using CT angiography data.     

PET肿瘤筛查:一项存在争议的检查方法

恶性肿瘤已成为目前危害人类生命健康的最严重疾病之一,早期发现及治疗是改善预后的关键.肿瘤筛查是早期发现肿瘤和癌前病变的重要途径.随着人们对肿瘤筛查手段要求的提高,PET这一高端影像学检查技术已越来越多地应用于肿瘤筛查.虽然大量数据显示PET可在人群中发现一些亚临床的恶性肿瘤,但在当代医疗实践中,PET用于肿瘤筛查依然存在很大的争议.该文旨在分析PET在目前肿瘤筛查方面的应用现状和存在的问题,以及对肿瘤筛查的意义和价值.     

CT在颅脑疾病诊断中的应用

CT是一种方便、迅速、安全、无创的检查方法,它能清楚地显示颅脑不同横断面的解剖关系和具体的脑组织结构.自20世纪70年代中期以来,CT在颅脑疾病诊断中的应用使人们对中枢神经系统疾病有了更深刻的认识.该文从缺血性脑梗死、颅内出血、脑肿瘤、脑外伤等方面介绍了CT在脑部疾病诊断中的应用及优点.     

Neural plasticity in blind cochlear implant users

Abstract

This study, using positron emission tomography, investigates the cortical activation generated by auditory stimulation in two congenitally blind cochlear implant users. In the patient with a relatively short history of deafness, activity increased in both auditory cortices and fell in the visual cortices. The patient with a longer period of deafness had greater activation of the visual cortices than the auditory cortices. A similar pattern of activity was seen when this patient subsequently had a second cochlear implant inserted into the opposite ear. The neural pathways formed after the restoration of auditory input in the congenitally blind can activate either the auditory or visual cortices. We suggest that the visual cortical activation demonstrated is of functional significance. Copyright © 2008 John Wiley & Sons, Ltd.