Intra- and inter-examiner reliability of digital images of skin donor areas in burns

SUMMARY OBJECTIVE: The main objective of this study was to evaluate intra- and inter-rater reliability in the analysis of digital images of donor areas for skin in burn patients using the CaPAS plugin in the ImageJ®. METHODS: Donor sites were reviewed by two independent reviewers in duplicate. The capture of images was standardized on the same device and distance (with a millimeter ruler), without a flash. The evaluators were trained to capture the images and use the plugin. RESULTS: We selected 70 images from donor areas, from men and women between 18 and 60 years old. In the analysis of intra-examiner reliability, eight of the nine variables exhibited excellent reliability (0.985-0.998) and one (entropy) exhibited good reliability (0.525). The same was true for the inter-examiner analysis: excellent reliability for eight variables (0.824-0.993) and good reliability for entropy (0.501). CONCLUSIONS: The CaPAS plugin has proven to be a reliable tool for use in research in skin donor areas in burns, as demonstrated by its excellent intra- and inter-examiner reliability values. This is a pioneering study in the quantitative assessment of skin donor areas in burn patients using the CaPAS plugin.

Populational brain models of diffusion tensor imaging for statistical analysis: a complementary information in common space

Abstract Introduction: The search for human brain templates has been progressing in the past decades and in order to understand disease patterns a need for a standard diffusion tensor imaging (DTI) dataset was raised. For this purposes, some DTI templates were developed which assist group analysis studies. In this study, complementary information to the most commonly used DTI template is proposed in order to offer a patient-specific statistical analysis on diffusion-weighted data. Methods 131 normal subjects were used to reconstruct a population-averaged template. After image pre processing, reconstruction and diagonalization, the eigenvalues and eigenvectors were used to reconstruct the quantitative DTI maps, namely fractional anisotropy (FA), mean diffusivity (MD), relative anisotropy (RA), and radial diffusivity (RD). The mean absolute error (MAE) was calculated using a voxel-wise procedure, which informs the global error regarding the mean intensity value for each quantitative map. Results the MAE values presented a low MAE estimate (max(MAE) = 0.112), showing a reasonable error measure between our DTI-USP-131 template and the classical DTI-JHU-81 approach, which also shows a statistical equivalence (p<0.05) with the classical DTI template. Hence, the complementary standard deviation (SD) maps for each quantitative DTI map can be added to the classical DTI-JHU-81 template. Conclusion In this study, variability DTI maps (SD maps) were reconstructed providing the possibility of a voxel-wise statistical analysis in patient-specific approach. Finally, the brain template (DTI-USP-131) described here was made available for research purposes on the web site (http://dx.doi.org/10.17632/br7bhs4h7m.1), being valuable to research and clinical applications.

Enhancing quality in Diffusion Tensor Imaging with anisotropic anomalous diffusion filter

Abstract Introduction: Diffusion tensor imaging (DTI) is an important medical imaging modality that has been useful to the study of microstructural changes in neurological diseases. However, the image noise level is a major practical limitation, in which one simple solution could be the average signal from a sequential acquisition. Nevertheless, this approach is time-consuming and is not often applied in the clinical routine. In this study, we aim to evaluate the anisotropic anomalous diffusion (AAD) filter in order to improve the general image quality of DTI. Methods A group of 20 healthy subjects with DTI data acquired (3T MR scanner) with different numbers of averages (N=1,2,4,6,8, and 16), where they were submitted to 2-D AAD and conventional anisotropic diffusion filters. The Relative Mean Error (RME), Structural Similarity Index (SSIM), Coefficient of Variation (CV) and tractography reconstruction were evaluated on Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC) maps. Results The results point to an improvement of up to 30% of CV, RME, and SSIM for the AAD filter, while up to 14% was found for the conventional AD filter (p<0.05). The tractography revealed a better estimative in fiber counting, where the AAD filter resulted in less FA variability. Furthermore, the AAD filter showed a quality improvement similar to a higher average approach, i.e. achieving an image quality equivalent to what was seen in two additional acquisitions. Conclusions In general, the AAD filter showed robustness in noise attenuation and global image quality improvement even in DTI images with high noise level.

Dimensão fractal na quantificação do grau de rejeição celular miocárdica pós-transplante cardíaco / Fractal dimension in quantifying the degree of myocardial cellular rejection after cardiac transplantation

INTRODUÇÃO: O termo "fractal" é derivado do latim fractus, que significa "irregular" ou "quebrado", considerando a estrutura observada como tendo uma dimensão não-inteira. Há muitos estudos que empregaram a Dimensão Fractal (DF) como uma ferramenta de diagnóstico. Um dos métodos mais comuns para o seu estudo é a "Box-plot counting" (Método de contagem de caixas). OBJETIVO: O objetivo do estudo foi tentar estabelecer a contribuição da DF na quantificação da rejeição celular miocárdica após o transplante cardíaco. MÉTODOS: Imagens microscópicas digitalizadas foram capturadas na resolução 800x600 (aumento de 100x). A DF foi calculada com auxílio do "software ImageJ", com adaptações. A classificação dos graus de rejeição foi de acordo com a "Sociedade Internacional de Transplante Cardíaco e Pulmonar" (ISHLT 2004). O relatório final do grau de rejeição foi confirmado e redefinido após exaustiva revisão das lâminas por um patologista experiente externo. No total, 658 lâminas foram avaliadas, com a seguinte distribuição entre os graus de rejeição (R): 335 (0R), 214 (1R), 70 (2R), 39 (3R). Os dados foram analisados estatisticamente com os testes Kruskal-Wallis e curvas ROC sendo considerados significantes valores de P < 0,05. RESULTADOS: Houve diferença estatística significativa entre os diferentes graus de rejeição com exceção da 3R versus 2R. A mesma tendência foi observada na aplicação da curva ROC. CONCLUSÃO: ADF pode contribuir para a avaliação da rejeição celular do miocárdio. Os valores mais elevados estiveram diretamente associados com graus progressivamente maiores de rejeição. Isso pode ajudar na tomada de decisão em casos duvidosos e naqueles que possam necessitar de intensificação da medicação imunossupressora.

INTRODUCTION: The term "Fractal" is derived from the Latin fractus meaning "irregular" or "broken" considering the observed structure with a non-integer dimension. There are many studies which employed the Fractal Dimension (FD) as a diagnostic tool. One of the most common methods for its study is the "Box Counting Method". OBJECTIVE: The aim of the present study was to try to establish the contribution of FD in the quantification of myocardial cellular rejection after cardiac transplantation. METHODS: Microscopic digital images were captured at 800x600 resolution (magnification 100x). FD was calculated with the aid of "ImageJ software" with adaptations. The classification of the degrees of rejection was in agreement with the "International Society for Heart and Lung Transplantation" (ISHLT 2004). The final report of the degree of rejection was confirmed and redefined after an exhaustive review of the slides by an external experienced pathologist. 658 slides were evaluated with the following distribution among the degrees of rejection (R): 335 (0R); 214 (1R); 70 (2R); 39 (3R). The data were statistically analyzed with Kruskal-Wallis tests and ROC curves being considered significant values of P < 0.05. RESULTS: There was significant statistical difference between the various degrees of rejection with the exception of R3 versus R2. The same trend was observed in applying the ROC curve. CONCLUSION: FD may contribute to the assessment of myocardial cellular rejection. Higher values are directly associated with progressively higher degrees of rejection. This may help in decision making of doubtful cases and those which contemplate the intensification of immunosuppressive medication.

Análise videodensitométrica da placa carotídea vulnerável: correlação histopatológica / Videodensitometric analysis of vulnerable carotid plaque: correlation with histological examination

Objetivos: Estabelecer a correlação entre a avaliação quantitativa, através da caracterização tecidual videodensitométrica, de imagens ultra-sonográficas bidimensionais digitalizadas e a análise histopatológica de placas carotídeas vulneráveis removidas cirurgicamente da artéria carótida, com estenose acima de 70 por cento, foram submetidos à caracterização tecidual ultra-sônica da placa antes do procedimento cirúrgico. Um software de computador (CaPAS - Carotid Plaque Analysis Software) foi especificamente desenvolvido para a análise videodensitométrica das imagens bidimensionais digitalizadas das placas carotídeas através de índice estatísticos de primeira (NMC - nível médio de cinza e DP - desvio padrão) e segunda (Entopia, Energia e Homogeneidade) ordens. Os pacientes foram divididos em 3 grupos de acordo com a sintomatologia: GRUPO I(n igual 6), pacientes com sintomas até 3 meses antecedendo o procedimento cirúrgico, GRUPO II(n igual 9), pacientes com sintomas acima de 3 meses antecedendo o procedimento cirúrgico e GRUPO III(n igual 10), pacientes assintomáticos. Os espécimes cirúrgicos foram analisados histopatologicamente para determinar as percentagens de gordura/necrose, fibrose e cálcio. Resultados: O NMC (primeira ordem) e os parâmetros de segunda ordem (entropia, energia e homogeneidade) diferenciaram os grupos clínicos, mas não se correlacionaram com os achados histopatológicos, mostrando apenas um tendência no NMC (primeira ordem) em refletir tais achados. Conclusão: A análise videodensitométrica de imagens bidimensionais digitalizadas pode ser usada para identificar placas vulneráveis e potencialmente instáveis, porém não se correlaciona com a proporção de componentes estruturais básicos avaliados histologicamente.

Quantitative analysis of segmental left ventricular wall motion using a polar representation of color kinesis images / Avaliação quantitativa da mobilidade segmentar do ventrículo esquerdo utilizando uma representação polar das imagens de "color kinesis"

A "color kinesis (CK) é uma técnica que representa o tempo e a magnitude da mobilidade global e segmentar do ventrículo esquerdo (MSVE) em tempo real. Neste estudo descreve-se um novo método para representar estas imagens na forma "bulls-eye" em mapas polares que provêem uma avaliação integrada e objetiva da MSVE. Foram avaliados indivíduos normais e em pacientes apresentando anormalidades na MSVE no estudo ecocardiográfico bidimensional com o objetivo de verificar a capacidade desta técnica para identificar e quantificar automaticamente a disfunção ventricular. Os dados obtidos demonstram que, embora a representação polar de imagens de CK seja factível em uma elevada proporção de indivíduos e possa proporcionar uma avaliação quantitativa da MSVE mais objetiva e menos dependente do operador, essa ferramenta de processamento de imagens mostrou limitada capacidade para identificação automática de disfunção ventricular quando comparada com a análise de observadores experientes.