A review of image processing methods for fetal head and brain analysis in ultrasound images

Background and objective: Examination of head shape and brain during the fetal period is paramount to evaluate head growth, predict neurodevelopment, and to diagnose fetal abnormalities. Prenatal ultrasound is the most used imaging modality to perform this evaluation. However, manual interpretation of these images is challenging and thus, image processing methods to aid this task have been proposed in the literature. This article aims to present a review of these state-of-the-art methods. Methods: In this work, it is intended to analyze and categorize the different image processing methods to evaluate fetal head and brain in ultrasound imaging. For that, a total of 109 articles published since 2010 were analyzed. Different applications are covered in this review, namely analysis of head shape and inner structures of the brain, standard clinical planes identification, fetal development analysis, and methods for image processing enhancement. Results: For each application, the reviewed techniques are categorized according to their theoretical approach, and the more suitable image processing methods to accurately analyze the head and brain are identified. Furthermore, future research needs are discussed. Finally, topics whose research is lacking in the literature are outlined, along with new fields of applications. Conclusions: A multitude of image processing methods has been proposed for fetal head and brain analysis. Summarily, techniques from different categories showed their potential to improve clinical practice. Nevertheless, further research must be conducted to potentiate the current methods, especially for 3D imaging analysis and acquisition and for abnormality detection. (c) 2022 Elsevier B.V. All rights reserved.FCT - Fundação para a Ciência e a Tecnologia(UIDB/00319/2020)This work was funded by projects “NORTE-01–0145-FEDER- 0 0 0 059 , NORTE-01-0145-FEDER-024300 and “NORTE-01–0145- FEDER-0 0 0 045 , supported by Northern Portugal Regional Opera- tional Programme (Norte2020), under the Portugal 2020 Partner- ship Agreement, through the European Regional Development Fund (FEDER). It was also funded by national funds, through the FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020 and by FCT and FCT/MCTES in the scope of the projects UIDB/05549/2020 and UIDP/05549/2020 . The authors also acknowledge support from FCT and the Euro- pean Social Found, through Programa Operacional Capital Humano (POCH), in the scope of the PhD grant SFRH/BD/136670/2018 and SFRH/BD/136721/2018

Fetal head circumference delineation using convolutional neural networks with registration-based ellipse fitting

Examination of head shape during the fetal period is an important task to evaluate head growth and to diagnose fetal abnormalities. Traditional clinical practice frequently relies on the estimation of head circumference (HC) from 2D ultrasound (US) images by manually fitting an ellipse to the fetal skull. However, this process tends to be prone to observer variability, and therefore, automatic approaches for HC delineation can bring added value for clinical practice. In this paper, an automatic method to accurately delineate the fetal head in US images is proposed. The proposed method is divided into two stages: (i) head delineation through a regression convolutional neural network (CNN) that estimates a gaussian-like map of the head contour; and (ii) robust ellipse fitting using a registration-based approach that combines the random sample consensus (RANSAC) and iterative closest point (ICP) algorithms. The proposed method was applied to the HC18 Challenge dataset, which contains 999 training and 335 testing images. Experiments showed that the proposed strategy achieved a mean average difference of -0.11 ± 2.67 mm and a Dice coefficient of 97.95 ± 1.12% against manual annotation, outperforming other approaches in the literature. The obtained results showed the effectiveness of the proposed method for HC delineation, suggesting its potential to be used in clinical practice for head shape assessment.FCT - Fundação para a Ciência e a Tecnologia(UIDB/00319/2020

The relationship between tourism, CO 2 emissions and economic growth: a case of Mediterranean countries

This study explores the impact of tourism on economic growth considering CO 2 emissions utilizing panel data techniques for a sample of Mediterranean countries. The cointegration tests reveal that there is a positive long-run equilibrium between tourism, CO 2 emissions and economic growth. This positive long-run relationship may suggest that tourism increases the level of CO 2 emissions and has a statistically significant impact on economic growth in Mediterranean countries. Emirmahmutoglu and Kose (2011. Testing for Granger causality in heterogeneous mixed panels. Economic Modelling, 28(3), 870–876.) test results reveal that the tourism-led growth hypothesis, which suggests that tourism contributes to economic growth, is valid for Egypt, Italy, and Spain. Additionally, there exists a bidirectional relationship between tourism and economic growth both in Morocco and Turkey. © 2018, © 2018 Asia Pacific Tourism Association

Course of the sFlt-1/PlGF ratio in fetal growth restriction and correlation with biometric measurements, feto-maternal Doppler parameters and time to delivery

Purpose!#!The study aimed to assess the course of the soluble Fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio in pregnant women with fetal growth restriction (FGR) and to evaluate potential associations between the sFlt-1/PlGF ratio and feto-maternal Doppler parameters, fetal biometric measurements and the time between study inclusion and birth ('time to delivery').!##!Methods!#!This was a retrospective longitudinal single center study including 52 FGR cases. The serum levels of sFlt-1 and PlGF were measured by using the BRAHMS Kryptor Compact PLUS. Fetal biometric and Doppler parameters, as well as the sFlt-1/PlGF ratio, were obtained both upon study inclusion and upon birth.!##!Results!#!Various associations between the levels of the biomarkers in maternal blood upon study inclusion and upon birth and sonographic parameters were observed in FGR cases: umbilical artery (p < 0.01), uterine arteries (p < 0.01), ductus venosus (p < 0.05), cerebroplacental ratio (CPR) (p < 0.01), femur length (p < 0.01) and birth weight (p < 0.01). The higher the sFlt-1/PlGF ratio upon study inclusion, the shorter the 'time to delivery' (p < 0.01). The multivariate regression analysis showed that the greater the daily percentage increase of the angiogenic markers, the shorter the 'time to delivery' (p < 0.01).!##!Conclusion!#!The fetal well-being, as measured by feto-maternal Doppler parameters such as CPR and the severity of the placental dysfunction, as measured by the urgency of birth and birth weight, is reflected by the level of the sFlt-1/PlGF ratio in the maternal serum. A rapid daily increase of the sFlt-1/PlGF ratio is significantly associated with the clinical progression of the disease

Course of the sFlt-1/PlGF ratio in fetal growth restriction and correlation with biometric measurements, feto-maternal Doppler parameters and time to delivery

Purpose The study aimed to assess the course of the soluble Fms-like tyrosine kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio in pregnant women with fetal growth restriction (FGR) and to evaluate potential associations between the sFlt-1/PlGF ratio and feto-maternal Doppler parameters, fetal biometric measurements and the time between study inclusion and birth ("time to delivery"). Methods This was a retrospective longitudinal single center study including 52 FGR cases. The serum levels of sFlt-1 and PlGF were measured by using the BRAHMS Kryptor Compact PLUS. Fetal biometric and Doppler parameters, as well as the sFlt-1/PlGF ratio, were obtained both upon study inclusion and upon birth. Results Various associations between the levels of the biomarkers in maternal blood upon study inclusion and upon birth and sonographic parameters were observed in FGR cases: umbilical artery (p < 0.01), uterine arteries (p < 0.01), ductus venosus (p < 0.05), cerebroplacental ratio (CPR) (p < 0.01), femur length (p < 0.01) and birth weight (p < 0.01). The higher the sFlt-1/PlGF ratio upon study inclusion, the shorter the "time to delivery" (p < 0.01). The multivariate regression analysis showed that the greater the daily percentage increase of the angiogenic markers, the shorter the "time to delivery" (p < 0.01). Conclusion The fetal well-being, as measured by feto-maternal Doppler parameters such as CPR and the severity of the placental dysfunction, as measured by the urgency of birth and birth weight, is reflected by the level of the sFlt-1/PlGF ratio in the maternal serum. A rapid daily increase of the sFlt-1/PlGF ratio is significantly associated with the clinical progression of the disease

Internal and external drivers for quality certification in the service industry: Do they have different impacts on success?

This paper presents the results of a study of hotels that are certified for quality management to identify the reasons for seeking quality certification. The authors analyse whether internal or external drivers for seeking certification have different impacts on benefits and the use of quality tools in the hotel industry. The analysis groups hotels according to the importance of their internal reasons for certification, and uses cluster analysis to identify the significant differences between groups of hotels. The findings for the 32 hotels analysed show that hotels that pursued certification for internal reasons develop better quality tools and have increased levels of benefit