The cause of the artifact in 4-slice helical computed tomography

The causes of the image artifacts in a 4-slice helical computed tomography have been discussed as follows: (1) changeover in pairs of data used in z interpolation, (2) sampling interval in z, and (3) the cone angle. This study analyzes the first two causes of the artifact and describes how the curre...

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Bibliographic Details
Published in:Medical physics (Lancaster) Vol. 31; no. 7; pp. 2033 - 2037
Main Authors: Taguchi, Katsuyuki, Aradate, Hiroshi, Saito, Yasuo, Zmora, Ilan, Han, Kyung S., Silver, Michael D.
Format: Journal Article
Language:English
Published: United States American Association of Physicists in Medicine 01.07.2004
Subjects:
Algorithms
Anatomy, Cross-Sectional - methods
charge exchange
Computed radiography
computed tomography
computerised tomography
helical scan
Image analysis
image artifacts
image reconstruction
image sampling
Imaging, Three-Dimensional - methods
interpolation
Medical image artifacts
medical image processing
Medical image reconstruction
Medical imaging
multi‐slice CT
phantoms
Physicists
Radiographic Image Enhancement - methods
Radiographic Image Interpretation, Computer-Assisted - methods
Reproducibility of Results
Sensitivity and Specificity
Tomography, Spiral Computed - methods
computed tomography
multi-slice CT
helical scan
image artifacts
ISSN:0094-2405, 2473-4209
Online Access:Get full text
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Summary:The causes of the image artifacts in a 4-slice helical computed tomography have been discussed as follows: (1) changeover in pairs of data used in z interpolation, (2) sampling interval in z, and (3) the cone angle. This study analyzes the first two causes of the artifact and describes how the current algorithm [K. Taguchi and H. Aradate, Radiology 205P, 390 (1997); 205P, 618 (1997); Med. Phys. 25, 550–561 (1998); H. Hu, ibid. 26, 5–18 (1999); S. Schaller et al., IEEE Trans. Med. Imaging 19, 822–834 (2000); K. Taguchi, Ph.D. thesis, University of Tsukuba, 2002] solves the problem. An interpolated sinogram for a slice at the edge of a ball phantom shows discontinuity caused by the changeover. If we extend the streak artifact in the reconstructed image, it crosses the focus orbit at the corresponding projection angle. Applying z filtering can reduce such causes by its feathering effect and mixing data obtained by different cone angles; the best results are provided when z filtering is applied to densely sampled helical data.
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ISSN:0094-2405
2473-4209
DOI:10.1118/1.1763005