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1.
AJNR Am J Neuroradiol ; 40(9): 1567-1574, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31467239

RESUMO

BACKGROUND AND PURPOSE: Fetuses with isolated nonsevere ventriculomegaly (INSVM) are at risk of presenting neurodevelopmental delay. However, the currently used clinical parameters are insufficient to select cases with high risk and determine whether subtle changes in brain development are present and might be a risk factor. The aim of this study was to perform a comprehensive evaluation of cortical development in INSVM by magnetic resonance (MR) imaging and assess its association with neonatal neurobehavior. MATERIALS AND METHODS: Thirty-two INSVM fetuses and 29 healthy controls between 26-28 weeks of gestation were evaluated using MR imaging. We compared sulci and fissure depth, cortical maturation grading of specific areas and sulci and volumes of different brain regions obtained from 3D brain reconstruction of cases and controls. Neonatal outcome was assessed by using the Neonatal Behavioral Assessment Scale at a mean of 4 ± 2 weeks after birth. RESULTS: Fetuses with INSVM showed less profound and underdeveloped sulcation, including the Sylvian fissure (mean depth: controls 16.8 ± 1.9 mm, versus INSVM 16.0 ± 1.6 mm; P = .01), and reduced global cortical grading (mean score: controls 42.9 ± 10.2 mm, versus INSVM: 37.8 ± 9.9 mm; P = .01). Fetuses with isolated nonsevere ventriculomegaly showed a mean global increase of gray matter volume (controls, 276.8 ± 46.0 ×10 mm3, versus INSVM 277.5 ± 49.3 ×10 mm3, P = .01), but decreased mean cortical volume in the frontal lobe (left: controls, 53.2 ± 8.8 ×10 mm3, versus INSVM 52.4 ± 5.4 ×10 mm3; P = < .01). Sulcal depth and brain volumes were significantly associated with the Neonatal Behavioral Assessment Scale severity (P = .005, Nagelkerke R2 = 0.732). CONCLUSIONS: INSVM fetuses showed differences in cortical development, including regions far from the lateral ventricles, that are associated with neonatal neurobehavior. These results suggest the possible use of these parameters to identify cases at higher risk of altered neurodevelopment.


Assuntos
Córtex Cerebral/embriologia , Córtex Cerebral/patologia , Hidrocefalia/complicações , Hidrocefalia/patologia , Doenças do Recém-Nascido/etiologia , Estudos de Casos e Controles , Córtex Cerebral/diagnóstico por imagem , Feminino , Feto , Humanos , Hidrocefalia/diagnóstico por imagem , Recém-Nascido , Imageamento por Ressonância Magnética/métodos , Masculino , Estudos Prospectivos , Fatores de Risco
2.
IEEE Trans Med Imaging ; 35(1): 89-97, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26186773

RESUMO

Although modern ultrasound acquisition systems allow recording of 3D echocardiographic images, tracking anatomical structures from them is still challenging. In addition, since these images are typically created from information obtained across several cardiac cycles, it is not yet possible to acquire high-quality 3D images from patients presenting varying heart rhythms. In this paper, we propose a method to estimate the motion field from multi-plane echocardiographic images of the left ventricle, which are acquired simultaneously during a single cardiac cycle. The method integrates tri-plane B-mode and tissue Doppler images acquired at different rotation angles around the long axis of the left ventricle. It uses a diffeomorphic continuous spatio-temporal transformation model with a spherical data representation for a better interpolation in the circumferential direction. This framework allows exploiting the spatial relation among the acquired planes. In addition, higher temporal resolution of the transformation in the beam direction is achieved by uncoupling the estimation of the different components of the velocity field. The method was validated using a realistic synthetic dataset including healthy and ischemic cases, obtaining errors of 0.14 ± 0.09 mm for displacements, 0.96 ± 1.03% for longitudinal strain and 3.94 ± 4.38% for radial strain estimation. In addition, the method was also demonstrated on a healthy volunteer and two patients with ischemia.


Assuntos
Ecocardiografia Doppler/métodos , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/fisiopatologia , Processamento de Imagem Assistida por Computador/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
3.
IEEE Trans Med Imaging ; 33(11): 2098-106, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24956282

RESUMO

We propose a technique for myocardial motion estimation based on image registration using both B-mode echocardiographic images and tissue Doppler sequences acquired interleaved. The velocity field is modeled continuously using B-splines and the spatiotemporal transform is constrained to be diffeomorphic. Images before scan conversion are used to improve the accuracy of the estimation. The similarity measure includes a model of the speckle pattern distribution of B-mode images. It also penalizes the disagreement between tissue Doppler velocities and the estimated velocity field. Registration accuracy is evaluated and compared to other alternatives using a realistic synthetic dataset, obtaining mean displacement errors of about 1 mm. Finally, the method is demonstrated on data acquired from six volunteers, both at rest and during exercise. Robustness is tested against low image quality and fast heart rates during exercise. Results show that our method provides a robust motion estimate in these situations.


Assuntos
Ecocardiografia Doppler/métodos , Coração/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Adulto , Feminino , Ventrículos do Coração/anatomia & histologia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Masculino , Movimento/fisiologia , Reprodutibilidade dos Testes , Função Ventricular/fisiologia , Adulto Jovem
4.
IEEE Trans Med Imaging ; 32(9): 1632-46, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23674439

RESUMO

This paper evaluates five 3D ultrasound tracking algorithms regarding their ability to quantify abnormal deformation in timing or amplitude. A synthetic database of B-mode image sequences modeling healthy, ischemic and dyssynchrony cases was generated for that purpose. This database is made publicly available to the community. It combines recent advances in electromechanical and ultrasound modeling. For modeling heart mechanics, the Bestel-Clement-Sorine electromechanical model was applied to a realistic geometry. For ultrasound modeling, we applied a fast simulation technique to produce realistic images on a set of scatterers moving according to the electromechanical simulation result. Tracking and strain accuracies were computed and compared for all evaluated algorithms. For tracking, all methods were estimating myocardial displacements with an error below 1 mm on the ischemic sequences. The introduction of a dilated geometry was found to have a significant impact on accuracy. Regarding strain, all methods were able to recover timing differences between segments, as well as low strain values. On all cases, radial strain was found to have a low accuracy in comparison to longitudinal and circumferential components.


Assuntos
Fenômenos Biomecânicos/fisiologia , Ecocardiografia Tridimensional/métodos , Modelos Cardiovasculares , Algoritmos , Simulação por Computador , Coração/anatomia & histologia , Coração/fisiologia , Coração/fisiopatologia , Humanos , Isquemia Miocárdica/diagnóstico por imagem , Isquemia Miocárdica/patologia , Isquemia Miocárdica/fisiopatologia , Miocárdio/patologia , Reprodutibilidade dos Testes
5.
Med Biol Eng Comput ; 51(11): 1209-19, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23359255

RESUMO

The anatomy and motion of the heart and the aorta are essential for patient-specific simulations of cardiac electrophysiology, wall mechanics and hemodynamics. Within the European integrated project euHeart, algorithms have been developed that allow to efficiently generate patient-specific anatomical models from medical images from multiple imaging modalities. These models, for instance, account for myocardial deformation, cardiac wall motion, and patient-specific tissue information like myocardial scar location. Furthermore, integration of algorithms for anatomy extraction and physiological simulations has been brought forward. Physiological simulations are linked closer to anatomical models by encoding tissue properties, like the muscle fibers, into segmentation meshes. Biophysical constraints are also utilized in combination with image analysis to assess tissue properties. Both examples show directions of how physiological simulations could provide new challenges and stimuli for image analysis research in the future.


Assuntos
Aorta/anatomia & histologia , Aorta/fisiologia , Coração/anatomia & histologia , Coração/fisiologia , Modelos Cardiovasculares , Algoritmos , Simulação por Computador , Angiografia Coronária , Técnicas Eletrofisiológicas Cardíacas , Hemodinâmica , Humanos , Imageamento Tridimensional , Angiografia por Ressonância Magnética , Medicina de Precisão
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