Premium
The cause of the artifact in 4‐slice helical computed tomography
Author(s) -
Taguchi Katsuyuki,
Aradate Hiroshi,
Saito Yasuo,
Zmora Ilan,
Han Kyung S.,
Silver Michael D.
Publication year - 2004
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1763005
Subject(s) - streak , imaging phantom , interpolation (computer graphics) , iterative reconstruction , computed tomography , tomography , mathematics , geometry , nuclear medicine , physics , optics , computer science , artificial intelligence , image (mathematics) , medicine , radiology
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.