- Oral presentation
- Open Access
Multicontrast 3D automated segmentation of cardiovascular images
https://doi.org/10.1186/1532-429X-18-S1-O114
© Bramlet et al. 2016
- Published: 27 January 2016
Keywords
- Image Segmentation
- Multiple Image
- Inversion Time
- Sequence Parameter
- Cardiovascular Image
Background
Our work explores the use of multiple contrasts to perform automated 3D cardiovascular image segmentation, with the goal of facilitating 3D assessment of subject-specific heart models.
The signal intensity of MR images is a function of intrinsic tissue parameters (e.g., spin density ρ, T1, and T2), and chosen sequence parameters (e.g., flip angle, TR, TI). MR images do not directly measure the underlying states of the tissue parameters, but rather provide observations of functions of the underlying states. When sequence parameters are selected properly, the contrast between tissue types is high enough to allow differentation of tissues via image segmentation.
Our work explores image segmentation using multiple image contrasts (i.e., multiple acquisitions using different sequence parameters). With multiple contrasts, the signal intensities from different images can be used to form a multidimensional feature space, increasing the distance between observations of different tissues as compared to a one-dimensional feature space based on a single image contrast.
Methods
Left , signal intensities of air, fat, myocardium, and blood using one contrast only. Right, signal intensities of the same tissues in a multidimensional feature space using both contrasts.
Results
A proof of concept 3D IR-bSSFP scan was collected with different inversion times; all other parameters were the same for both scans using TI = 49 ms and TI = 330 ms. Images were processed using the FMRIB Software Library (FSL). Images were registered with the FLIRT tool, employing mutual information as the similarity metric, then cropped to include only the heart. The cropped, registered images were segmented by inputting both contrasts into the FAST tool. The number of tissues was specified as four, with the intent of differentiating air, fat, blood, and myocardium.
Left , manual segmentation of tissues (for reference). Center, FAST with one image contrast. Right, FAST with two image contrasts. Arrows indicate large areas of error when using only one image contrast.
Conclusions
As more advanced 3D viewing tools become available, the need to automate the segmentation process grows. This simple technique demonstrates a shift in imaging goal from high resolution 2D acquisition to tissue identification and lays the foundation for future sequence design.
Authors’ Affiliations
Copyright
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.