Quantification of tumor burden in multiple myeloma by atlas-based semi-automatic segmentation of WB-DWI

BACKGROUND: Whole-body diffusion weighted imaging (WB-DWI) has proven value to detect multiple myeloma (MM) lesions. However, the large volume of imaging data and the presence of numerous lesions makes the reading process challenging. The aim of the current study was to develop a semi-automatic lesion segmentation algorithm for WB-DWI images in MM patients and to evaluate this smart-algorithm (SA) performance by comparing it to the manual segmentations performed by radiologists. METHODS: An atlas-based segmentation was developed to remove the high-signal intensity normal tissues on WB-DWI and to restrict the lesion area to the skeleton. Then, an outlier threshold-based segmentation was applied to WB-DWI images, and the segmented area's signal intensity was compared to the average signal intensity of a low-fat muscle on T1-weighted images. This method was validated in 22 whole-body DWI images of patients diagnosed with MM. Dice similarity coefficient (DSC), sensitivity and positive predictive value (PPV) were computed to evaluate the SA performance against the gold standard (GS) and to compare with the radiologists. A non-parametric Wilcoxon test was also performed. Apparent diffusion coefficient (ADC) histogram metrics and lesion volume were extracted for the GS segmentation and for the correctly identified lesions by SA and their correlation was assessed. RESULTS: The mean inter-radiologists DSC was 0.323 ± 0.268. The SA vs GS achieved a DSC of 0.274 ± 0.227, sensitivity of 0.764 ± 0.276 and PPV 0.217 ± 0.207. Its distribution was not significantly different from the mean DSC of inter-radiologist segmentation (p = 0.108, Wilcoxon test). ADC and lesion volume intraclass correlation coefficient (ICC) of the GS and of the correctly identified lesions by the SA was 0.996 for the median and 0.894 for the lesion volume (p < 0.001). The duration of the lesion volume segmentation by the SA was, on average, 10.22 ± 0.86 min, per patient. CONCLUSIONS: The SA provides equally reproducible segmentation results when compared to the manual segmentation of radiologists. Thus, the proposed method offers robust and efficient segmentation of MM lesions on WB-DWI. This method may aid accurate assessment of tumor burden and therefore provide insights to treatment response assessment.publishersversionpublishe

Antony and Cleopatra

Analysis done 199

Errors in protein synthesis increase the level of saturated fatty acids and affect the overall lipid profiles of yeast

The occurrence of protein synthesis errors (mistranslation) above the typical mean mistranslation level of 10-4 is mostly deleterious to yeast, zebrafish and mammal cells. Previous yeast studies have shown that mistranslation affects fitness and deregulates genes related to lipid metabolism, but there is no experimental proof that such errors alter yeast lipid profiles. We engineered yeast strains to misincorporate serine at alanine and glycine sites on a global scale and evaluated the putative effects on the lipidome. Lipids from whole cells were extracted and analysed by thin layer chromatography (TLC), liquid chromatography-mass spectrometry(LC-MS) and gas chromatography (GC). Oxidative damage, fatty acid desaturation and membrane fluidity changes were screened to identify putative alterations in lipid profiles in both logarithmic (fermentative) and post-diauxic shift (respiratory) phases. There were alterations in several lipid classes, namely lyso-phosphatidylcholine, phosphatidic acid, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and triglyceride, and in the fatty acid profiles, namely C16:1, C16:0, C18:1 and C18:0. Overall, the relative content of lipid species with saturated FA increased in detriment of those with unsaturated fatty acids. The expression of the OLE1 mRNA was deregulated, but phospholipid fluidity changes were not observed. These data expand current knowledge of mistranslation biology and highlight its putative roles in human diseases.publishe

Cuidados de saúde e território: um debate em torno de uma abordagem integrada

As alterações que, essencialmente no decurso da última década, têm surgido nos domínios económico, político e social, com repercussões no âmbito dos serviços de saúde, justificam um repensar dos processos de formulação de políticas da saúde. De facto, este conjunto de alterações coloca em discussão as noções de equidade e eficiência à luz das dinâmicas territoriais, obrigando ao reajustamento das perspetivas teórico-concetuais predominantes e à revisão de estratégias de intervenção vulgarmente utilizadas neste campo. Neste texto, procura esclarecer-se a relação entre cuidados de saúde e território tendo por base dois fatores: a natureza geográfica de acessibilidade aos cuidados de saúde atendendo, quer à dicotomia urbano/rural, quer às recentes tendências de reorganização de vários sistemas de saúde numa ótica de racionalização de recursos e de centralização de serviços, e as implicações no modo como os serviços de saúde passam a organizar-se territorialmente e se articulam, quer entre si, quer com o modelo de organização dos sistemas urbanos existentes. O objetivo é, justamente, refletir sobre esses desafios que, agudizados perante o atual contexto, se colocam às decisões políticas no âmbito dos cuidados de saúde e, consequentemente, discutir possíveis estratégias de intervenção que se afigurem mais territorialmente integradas