document: Favorable noise uniformity properties of Fourier-based interpolation and reconstruction approaches in single-slice helical computed tomography Volumes reconstructed by standard methods from single-slice helical computed tomography -LRB- CT -RRB- data have been shown to have noise levels that are highly nonuniform relative to those in conventional CT. . These noise nonuniformities can affect low-contrast object detectability and have also been identified as the cause of the zebra artifacts that plague maximum intensity projection -LRB- MIP -RRB- images of such volumes . While these spatially variant noise levels have their root in the peculiarities of the helical scan geometry , there is also a strong dependence on the interpolation and reconstruction algorithms employed . In this paper , we seek to develop image reconstruction strategies that eliminate or reduce , at its source , the nonuniformity of noise levels in helical CT relative to that in conventional CT. . We pursue two approaches , independently and in concert . We argue , and verify , that Fourier-based longitudinal interpolation approaches lead to more uniform noise ratios than do the standard 360LI and 180LI approaches . We also demonstrate that a Fourier-based fan-to-parallel rebinning algorithm , used as an alternative to fanbeam filtered backprojection for slice reconstruction , also leads to more uniform noise ratios , even when making use of the 180LI and 360LI interpolation approaches
doc_bio_tags: O B I I O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O
extractive_keyphrases: reconstruction approaches noise uniformity properties conventional ct more uniform noise ratios zebra artifacts
abstractive_keyphrases: fourier-based interpolation single-slice helical computed tomography medical diagnostic imaging fourier-based fan-to-parallel rebinning algorithm low-contrast object detectability maximum intensity projection images helical span geometry