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CT colonography: size reduction of submerged colorectal polyps due to electronic cleansing and CT-window settings.
OBJECTIVES: To assess whether electronic cleansing (EC) of tagged residue and different computed tomography (CT) windows influence the size of colorectal polyps in CT colonography (CTC). METHODS: A database of 894 colonoscopy-validated CTC datasets of a low-prevalence cohort was retrospectively reviewed to identify patients with polyps ≥6 mm that were entirely submerged in tagged residue. Ten radiologists independently measured the largest diameter of each polyp, two-dimensionally, before and after EC in colon, bone, and soft-tissue-windows, in randomised order. Differences in size and polyp count before and after EC were calculated for size categories ≥6 mm and ≥10 mm. Statistical testing involved 95% confidence interval, intraclass correlation and mixed-model ANOVA. RESULTS: Thirty-seven patients with 48 polyps were included. Mean polyp size before EC was 9.8 mm in colon, 9.9 mm in bone and 8.2 mm in soft-tissue windows. After EC, the mean polyp size decreased significantly to 9.4 mm in colon, 9.1 mm in bone and 7.1 mm in soft-tissue windows. Compared to unsubtracted colon windows, EC, performed in colon, bone and soft-tissue windows, led to a shift of 6 (12,5%), 10 (20.8%) and 25 (52.1%) polyps ≥6 mm into the next smaller size category, thus affecting patient risk stratification. CONCLUSIONS: EC and narrow CT windows significantly reduce the size of polyps submerged in tagged residue. Polyp measurements should be performed in unsubtracted colon windows. KEY POINTS: • EC significantly reduces the size of polyps submerged in tagged residue. • Abdominal CT-window settings significantly underestimate 2D sizes of submerged polyps. • Size reduction in EC is significantly greater in narrow than wide windows. • Underestimation of polyp size due to EC may lead to inadequate treatment. • Polyp measurements should be performed in unsubtracted images using a colon window
Masters of Their Working Hours? Zu Organisation, Intensität und Dauer handwerklicher Arbeit im Spätmittelalter und früher Neuzeit
lnformation on the working hours of medieval and early modern artisans has mainly passed on to us by normative sources. They contain dimensions (6 to 18 hours per day) which are very difficult to be interpreted and to be examined concerning their reality and their comparability to the situation of today. The author tries to get hold of the problem by the use and critical interpretation of additional sources covering broader aspects of work and time: work as a general phenomenon in society and its valuation, the changing attitude of man towards time from the 14th to the 17th century, the opposition of journeymen against long working hours, the attempts of artisans and workers, to be proved from the 14th century onwards, to become ,masters of their working hours', the different trends towards a reduction ofworking hours, information on weekly working time (the medieval five-day week and the Reformation's influence on it) and its comparison with daily working hours, the connection of working hours with productivity and quality, the generally negative attitude towards idleness and the formation of a positive attitude towards leisure time arising only in the 17th and 18th century.lnformation on the working hours of medieval and early modern artisans has mainly passed on to us by normative sources. They contain dimensions (6 to 18 hours per day) which are very difficult to be interpreted and to be examined concerning their reality and their comparability to the situation of today. The author tries to get hold of the problem by the use and critical interpretation of additional sources covering broader aspects of work and time: work as a general phenomenon in society and its valuation, the changing attitude of man towards time from the 14th to the 17th century, the opposition of journeymen against long working hours, the attempts of artisans and workers, to be proved from the 14th century onwards, to become ,masters of their working hours', the different trends towards a reduction ofworking hours, information on weekly working time (the medieval five-day week and the Reformation's influence on it) and its comparison with daily working hours, the connection of working hours with productivity and quality, the generally negative attitude towards idleness and the formation of a positive attitude towards leisure time arising only in the 17th and 18th century