LitCovid-sentences  

PMC:7473770 / 49007-50963 JSONTXT 6 Projects

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Id Subject Object Predicate Lexical cue
T408 0-131 Sentence denotes Resolution estimates are challenging for tissue reconstructions due to the absence of sharp edges or features of well defined size.
T409 132-202 Sentence denotes Here, we follow the approach known as Fourier-shell correlation (FSC).
T410 203-366 Sentence denotes Accordingly, an upper bound for the resolution is be obtained in the following way: the CT scan is split into two, and from each half a 3D volume is reconstructed.
T411 367-546 Sentence denotes After registry, that is, mutual alignment of the volumes, the correlation between the two independent reconstructions in Fourier space is plotted as function of spatial frequency.
T412 547-702 Sentence denotes This correlation must not necessarily reflect the pure system resolution, but instead the range of spatial frequencies over which the results are reliable.
T413 703-827 Sentence denotes As such it is not only affected by the system resolution but also by the sample contrast and the noise of the specific scan.
T414 828-1000 Sentence denotes Further, it represents an average over all structures, not taking into account that features with stronger/weaker contrast can correspondingly show higher/lower resolution.
T415 1001-1092 Sentence denotes Here the Fourier operation for FSC was implemented with a Kaiser-Bessel window of 7 pixels.
T416 1093-1238 Sentence denotes For the parallel-beam data, a central volume of 650 × 650 × 650 voxels was correlated, for the cone-beam data a volume of 685 × 680 × 250 voxels.
T417 1239-1373 Sentence denotes These sub-volumes were selected to obtain the average values for the tissue while minimizing contributions from paraffin-filled holes.
T418 1374-1430 Sentence denotes The correlation curves are shown in Appendix 2—figure 1.
T419 1431-1554 Sentence denotes The intersection of the curve with the half-bit threshold yields the resolution estimate, indicated with dashed black line.
T420 1555-1699 Sentence denotes Correspondingly, a half-period resolution of 0.71⁢μ⁢m and 0.39⁢μ⁢m (or better) is obtained for the parallel and cone beam dataset, respectively.
T421 1700-1910 Sentence denotes However, since the splitted dataset resulted in only 721 angles for the reconstruction, i.e. the resolution estimate is severely affected by under-sampling artifacts, and hence can only serve as an upper bound.
T422 1911-1956 Sentence denotes Appendix 2—figure 1 illustrates the analysis.