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Descripción
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| we proposed a new scheme for breathing motion compensation in MRI perfusion studies based on non-rigid registration. In order to reduce the influence of the change of intensity, which is induced by the contrast agent as it passes through the both heart ventricles and the myocardium, we used a serial registration scheme where only subsequent images of the series are registered. In addition, we have introduced a new image similarity measure that is based on normalized gradient fields and was improved over the previous proposal in (Haber and Modersitzki, 2005). This measure is of a very local nature, and therefore, well suited to obtain non-rigid registration for images with local contrast change, as it is the case in myocardial perfusion MRI. Our experiments show that using this measure alone yields a good registration only for the images of the series that exhibit a high contrast and, hence, strong gradients in the regions of interest. When the intensity contrast is low, small registration errors may occur and, because of the serial registration scheme, these errors accumulate resulting an increasing misalignment over the series time course. We were able to improve these results by combining the normalized gradient field based cost function with the sum of squared differences, so that the first would take precedence in regions with high contrast and, hence, strong gradients, while the latter ensures a steady registration in areas with low contrast and, therefore, small gradients. | |
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Internacional
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Si |
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DOI
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Edición del Libro
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0 |
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Editorial del Libro
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In-Tech |
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ISBN
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978-953-7619-57-2 |
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Serie
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Título del Libro
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New Developments in Biomedical Engineering |
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Desde página
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235 |
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Hasta página
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247 |