Métodos para quantificação da artéria carótida em imagens de ultrassom modo-B e Doppler.

Abstract

Bland-Altman e o coeficiente de correlação validaram esta metodologia que, complementada pela interface gráfica amigável do aplicativo, pode auxiliar os clínicos em seus estudos de larga escala, baseados nas imagens Doppler ultrassonográficas, com as seguintes vantagens: redução do tempo operacional e de resultados subjetivos e aumento do grau de reprodutibilidade dos resultados. Palavras-chave: Ultrassonografia modo-B. Ultrassonografia Doppler. Quantificação da artéria carótida. Contornos ativos. Modelo matemático da artéria. Gráfico de velocidade do sangue. Fluxo de sangue. Integral de velocidade e tempo. ABSTRACTIn the field of image-based diagnostic medicine, low cost and noninvasive B-mode ultrasound technique have supported the researches which investigates the relation between the carotid intima-media thickness (IMT) and the development of cardiovascular diseases. Other ultrasound technique, that offers a different approach to study these diseases, is based on Doppler effect and has also been extensively used in clinical sites to measure blood velocity and flow in peripheral arteries. In this work, computational methods were implemented and analyzed to extract quantitative data from 2D images of arteries. Tests with B-mode images covered the combination of filtering techniques and active contour algorithms, in order to detect the arterial wall interfaces and to measure IMT and lumen diameter (LD). One mathematical model and seven real images of the common carotid artery were used in this study which, among several filters and algorithms combinations, showed similar quantitative results for DL measurements. However, for IMT, the small thickness of intima-media layer led to undesirable variation results. To measure blood velocity by using Doppler mode, a semi-automatic methodology was implemented in a computational tool to detect the spectrum envelope of the velocity graphic. A comparative analysis between commercial ultrasound systems operated by specialists and this tool included systolic peak velocities and velocity-time integral (VTI) of the common carotid and brachial arteries and of echocardiographic exams.Bland-Altman's analysis and the correlation coefficient validated this methodology which, besides the user friendly graphical interface of the tool, may help the clinicians for their large-scale studies based on Doppler ultrasound images, with the following advantages: to save operational time, to lower subjective results, and to support measurement reproducibility. Keywords: B-mode ultrasound. Doppler ultrasound. Carotid artery quantification. Active contour. Mathematical model of the artery. Blood velocity. Blood flow. Velocitytime integral.

B-mode and Doppler ultrasonography in the assessment of the common carotid arteries of equines and mules and the relation with body mass, age and neck circumference

“…On the other hand, equine females were found to have positive correlations with the longitudinal and transversal diameter and with neck circumference, including neck length. It was possible to ascertain that the body mass of all animals influenced in the longitudinal and transversal diameter of the common carotid arteries, similarly to what had been found by Higa (2009) and Denarie et al (2000) and Zanini (2012) in humans and by Cipone et al (1997) and Aguiar (2015) in equines.…”

Comparação das artérias carótidas comuns de equinos e muares por ultrassonografia modo-B e Doppler espectral e a relação com a massa corpórea

“…Isso contrapõe Cipone et al (1997), em estudo com equinos, em cujos machos os valores de VS foram superiores. O modo-B não se correlacionou significativamente com a massa corpórea nos gêneros de equinos e muares, mas, conforme explicitado por Higa (2009), Denarie et al (2000), Krejza et al (2006) e Zanini (2012) em humanos, a massa corpórea influencia nos diâmetros das artérias carótidas comuns.…”

“…Pesquisas de ultrassonografia modo-B e Doppler espectral nas artérias carótidas comuns já foram relatadas em equinos (Cipone et al, 1997;Schumucker et al, 2000;Aguiar, 2015), entretanto não há estudo com os muares na literatura consultada. As pesquisas envolvendo equinos descrevem a associação desse vaso com a massa corpórea (Cipone et al, 1997), e essa mesma ocorrência é relatada em seres humanos (Higa, 2009;Denarie et al, 2000;Zanini, 2012).…”