Reducing the influence of spatial resolution to improve quantitative accuracy in emission tomography: a comparison of potential strategies
- Publication Type:
- Journal Article
- Nuclear Instrumentation & Methods in Physics Research Section A, 2006, 569 (2), pp. 462 - 466
- Issue Date:
The goal of this paper is to compare strategies for reducing partial volume effects by either minimising the cause (i.e. improving resolution) or correcting the effect. Correction for resolution loss can be achieved either by modelling the resolution for ise in iterative reconstruction or by imposing contraints based on knowledge of the underlying anatomy. Approaches to partial volume correctiuon largely rely on knoweldge of the underlying anatomy, based on well-registered high-resolution anatomical imaging modalities (CT ot MRI). Corrections can be applied bu considering the signal loss that results by smoothing the high-resolution modality to the same resolution as obntained in emission tomography. A physical phantom representing the central brain structures was used to evaluate the quantitative accuracy of the various strategies for either improving resolution or correcting for partial volume effects. Inclusion of resolution in the reconstruction model imporved the measured contrast for the central brain structures but still underestimated the true object contrast (~0.70). Use of information on the boundaries of the structures in conjunction with a smoothing prior using maximum entropy reconstruction achieved some degree of contrast enhancement and improved the noise properties of the resulting images. Partial volume correction based on segmentation of registered anatomical images and knowledge of the reconstructred resolution permitted more accurate quantificationm of the target to background ration for individual brain structures.
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