Efficient, Unbiased Quality Assurance Of Automated Tissue Analysis Applicable To Daily Pathology Practice

Introduction/ Background Quantification of tissue biomarkers is increasingly demanded for diagnosis and is commonly performed by expert pathologists using microscopy of stained tissue at high magnification. This manual scoring is a reasonably fast, supervised procedure, but it suffers from inter- and intra-observer differences due to a) differences in selection of regions of interest, b) differences in quantity estimation, c) intra-tissue variability of biomarker expression. Computers and whole slide microscopy scanners have made it feasible to perform high-capacity analysis of high resolution images of tissue. Image analysis (IA) enables better reproducibility, but conversely, the unsupervised analysis introduces challenges regarding accuracy. Furthermore, borderline cases will always have to be rigorously inspected by pathologists. Many IA evaluation methods exist, but for pathology, a supervised comparison of experimental segmentation to an appropriately obtained standard criterion is the optimal strategy. The production of standard criterion necessitates evaluation of whole slide images to eliminate any possible region sampling bias while inter- and intra- observer bias can only be minimized by replacing any manual estimates by objective measurements. A logical step is thus to change the task of the pathologist from quantity estimation to verifying the output an automated procedure reports. Still, verification of entire tissue slides is in daily pathology practice too time-consuming. To minimize the workload pathology is turning to stereological methods which aim to efficiently quantify matter unbiasedly and have been proved useful for supervised validation of automated analysis for Ki67 scoring of breast cancer. However, the workload still needs to be reduced to a level comparable to the manual scoring procedure. Aims We aim to enable high accuracy, objective evaluation of automated image analysis with a workload and workflow feasible for daily pathology practice. This regards both production of reference data for image analysis tool calibration and continuous quality control inspection of borderline cases. Methods This study investigates proportionate sampling, a very efficient stereological sampling scheme utilizing weighted sampling of regions of automated image analysis for manual evaluation of automated IA. The sampling of regions to be inspected by a pathologist draws upon the IA to assign probability weights to all regions. This results in a highly efficient, unbiased sampling and quality assurance estimate for the automated image analysis. Results Presented here is proof-of-concept of an efficient, unbiased image analysis evaluation methodology. The task of the pathologist is changed from quantity estimation to instead annotate discrepancies between the output from the IA and the tissue in a few sampled regions. From the annotations an unbiased quality assurance estimate of the IA can be estimated including levels of accuracy obtainable and expected workloads. This confirms that the stereological proportionate sampling enables manual verification of automated whole slide image analysis for unbiased reference dataset creation and quality control inspection in borderline cases. Furthermore, the methodology is easily integrated into both image analysis platforms for production of reference data sets and laboratory information systems for daily pathology practices.

Towards a computer aided diagnosis system dedicated to virtual microscopy based on stereology sampling and diffusion maps

An original strategy is presented, combining stereological sampling methods based on test grids and data reduction methods based on diffusion maps, in order to build a knowledge image database with no bias introduced by a subjective choice of exploration areas. The practical application of the exposed methodology concerns virtual slides of breast tumors

Considerações para o monitoramento do uso do solo com dados MODIS para longos períodos e em escala regional, e sua aplicação na bacia do Alto Taquari, MS/MT.

Este artigo discute uma metodologia para a classificação sistemática do uso e cobertura do solo em escala regional e para períodos extensos de tempo. O cerne desta metodologia está baseado no trabalho descrito em JONATHAN et al. (2005, 2006) e se fundamenta na análise de dados multitemporais provenientes do sensor MODIS (Moderate Resolution Imaging Spectroradiometer), o qual se encontra a bordo dos satélites Terra e Aqua da NASA e apresenta propriedades de alta frequência temporal, extensa cobertura, e baixíssimo custo para aquisição de dados. Neste trabalho, realizou-se uma avaliação dos maiores potenciais e possíveis impedimentos da aplicação desta metodologia para o monitoramento plurianual do uso e cobertura do solo, concluindo-se ser de fato viável monitorar grandes regiões por longos períodos de tempo com baixo custo e altos níveis de automação. Neste sentido, tomou-se como área de estudos a Bacia do Alto Taquari, localizada nos estados de Mato Grosso do Sul e Mato Grosso, de forma a se enfatizar a relevância da aplicação desta abordagem para a detecção e quantificação de fenômenos como o desflorestamento e a dinâmica agrícola, que são por sua vez essenciais para o melhor entendimento dos principais processos de degradação relacionados ao ecossistema do Pantanal

Regional scale land use/land cover classification using temporal series of MODIS data.

This paper describes a methodology for systematic land use/land cover classification on a regional scale, with emphasis on a low cost and highly automatized approach. This methodology is based on multitemporal analyses of surface reflectance data from the Moderate Resolution Imaging Spectroradiometer (MODIS), which is located on board NASA's Terra and Aqua satellites and features high temporal frequency, extensive coverage, and extremely low costs for data acquisition. A sequence of automatized procedures were developed for MODIS data pre-processing, as well as for the training and execution of a supervised classification algorithm, where temporal profiles are fitted to smooth polynomial curves and intelligent curve features are then computed in order to reduce data dimensionality and improve profile interpretability, thus providing a more robust classification approach. A case study was performed in the High Taquari Basin, in the states of Mato Grosso do Sul and Mato Grosso, Brazil, which showed that the method was indeed capable of generalizing well over the entire region of study (over 25,000km2), effectively discriminating between areas of agriculture, pasture, and savannah. The methodology was also seen to be quite successful in identifying areas of deforestation, which is of particular interest for the monitoring of land use and land use change in the region

Preliminary definitions for the sonographic features of synovitis in children

Objectives Musculoskeletal ultrasonography (US) has the potential to be an important tool in the assessment of disease activity in childhood arthritides. To assess pathology, clear definitions for synovitis need to be developed first. The aim of this study was to develop and validate these definitions through an international consensus process. Methods The decision on which US techniques to use, the components to be included in the definitions as well as the final wording were developed by 31 ultrasound experts in a consensus process. A Likert scale of 1-5 with 1 indicating complete disagreement and 5 complete agreement was used. A minimum of 80% of the experts scoring 4 or 5 was required for final approval. The definitions were then validated on 120 standardized US images of the wrist, MCP and tibiotalar joints displaying various degrees of synovitis at various ages. Results B-Mode and Doppler should be used for assessing synovitis in children. A US definition of the various components (i.e. synovial hypertrophy, effusion and Doppler signal within the synovium) was developed. The definition was validated on still images with a median of 89% (range 80-100) of participants scoring it as 4 or 5 on a Likert scale. Conclusions US definitions of synovitis and its elementary components covering the entire pediatric age range were successfully developed through a Delphi process and validated in a web-based still images exercise. These results provide the basis for the standardized US assessment of synovitis in clinical practice and research

The Use of Pedicled Perforator Flaps in Chest Reconstruction: A Systematic Review of Outcomes and Reliability

BACKGROUND: In recent years, pedicled perforator flaps have revolutionized plastic surgery by reducing donor site morbidity and ensuring larger and deeper reconstructions with local pedicled cutaneous flaps. The aim of the study was to make a systematic review of perforator pedicled propeller flaps (PPPFs) in chest reconstruction. METHODS: Pubmed and Cochrane databases were searched from 1989 to October 2016 for articles describing the use of PPPFs in chest reconstruction. The preferred reporting items for systematic reviews and meta analyses statement was used in the selection process. The review was registered on international prospective register of systematic reviews. Furthermore, operative technique, indications and complications were searched. RESULTS: Twenty-four articles were selected (174 patients and 182 flaps). Oncological surgery was the first etiology (34.5%), followed by infections (11.5%), chest keloid scars (6.23%), malformations (4.6%), burns (3.4%), chronic ulcers (2.3%), Verneuil disease (1.8%), and acute wounds (1.8%). The arc of rotation was between 90° and 120° in 24.2%. The mean surface of flaps was 127.45 ± 123.11 cm. Dissection was subfascial in 78.5% of the cases. Complications were found in 9.9% of patients and included mainly wound dehiscence (4.4%) and hematoma/seroma (2.2%). One case of total necrosis (0.5%) and 2 cases of partial necrosis (1.1%) were found. CONCLUSIONS: The possibility of numerous pedicles makes it possible for PPPFs to offset most areas of wall chest defects. Furthermore, this surgical technique is reliable and reproducible, with lower donor site morbidity than that in the case of muscular flaps, which are classically used in this location

Low-Temperature Physics

Contains reports on five research projects

Low Temperature Physics

Contains reports on six research projects