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The quality of reconstructed 3D images in multidetector-row helical CT: experimental study involving scan parameters.

Shin JH, Lee HK, Choi CG, Suh DC, Lim TH, Kang W - Korean J Radiol (2002 Jan-Mar)

Bottom Line: Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering.The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used.Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT

Objective: To determine which multidetector-row helical CT scanning technique provides the best-quality reconstructed 3D images, and to assess differences in image quality according to the levels of the scanning parameters used.

Materials and methods: Four objects with different surfaces and contours were scanned using multidetector-row helical CT at three detector-row collimations (1.25, 2.50, 5.00 mm), two pitches (3.0, 6.0), and three different degrees of overlap between the reconstructed slices (0%, 25%, 50%). Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering. The 72 images were graded on a scale from 1 (worst) to 5 (best) for each of four rating criteria, giving a mean score for each criterion and an overall mean score. Statistical analysis was used to assess differences in image quality according to scanning parameter levels.

Results: The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used. With regard to detector-row collimation and pitch, all levels of scanning parameters gave rise to significant differences, while in the degree of overlap of reconstructed slices, there were significant differences between overlap of 0% and of 50% in all levels of scanning parameters, and between overlap of 25% and of 50% in overall accuracy and overall mean score. Among the 18 scanning sequences, the highest score (4.94) was achieved with 1.25 mm detector-row collimation, 3.0 pitch, and 50% overlap between reconstructed slices.

Conclusion: Comparison of the quality of reconstructed 3D images obtained using multidetector-row helical CT and various scanning techniques indicated that the 1.25 mm, 3.0, 50% scanning sequence was best. Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased.

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Image quality of the cup according to the level of pitch. Image quality, i.e. definition of the outer margin or smoothness of the curved area, is better at a pitch of 3.0 than at one of 6.0.A. 2.50 mm, 3.0, 50%B. 2.50 mm, 6.0, 50%
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Figure 7: Image quality of the cup according to the level of pitch. Image quality, i.e. definition of the outer margin or smoothness of the curved area, is better at a pitch of 3.0 than at one of 6.0.A. 2.50 mm, 3.0, 50%B. 2.50 mm, 6.0, 50%

Mentions: Using the fitted ANOVA model, we estimated the mean score and 95% confidence intervals of each scanning sequence for each rating criterion and the overall mean score (Figs. 2-5). Among the 18 sequences, that in which detector-row collimation, pitch, and overlap of reconstructed slices were, respectively, 1.25 mm, 3.0, and 50%, showed the highest score for each rating criterion, and highest overall mean score (4.94). Image quality improved as detector-row collimation decreased (Fig. 6); as pitch was reduced from 6.0 to 3.0 (Fig. 7); and as the degree of overlap between reconstructed slices increased (Fig. 8).


The quality of reconstructed 3D images in multidetector-row helical CT: experimental study involving scan parameters.

Shin JH, Lee HK, Choi CG, Suh DC, Lim TH, Kang W - Korean J Radiol (2002 Jan-Mar)

Image quality of the cup according to the level of pitch. Image quality, i.e. definition of the outer margin or smoothness of the curved area, is better at a pitch of 3.0 than at one of 6.0.A. 2.50 mm, 3.0, 50%B. 2.50 mm, 6.0, 50%
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2713987&req=5

Figure 7: Image quality of the cup according to the level of pitch. Image quality, i.e. definition of the outer margin or smoothness of the curved area, is better at a pitch of 3.0 than at one of 6.0.A. 2.50 mm, 3.0, 50%B. 2.50 mm, 6.0, 50%
Mentions: Using the fitted ANOVA model, we estimated the mean score and 95% confidence intervals of each scanning sequence for each rating criterion and the overall mean score (Figs. 2-5). Among the 18 sequences, that in which detector-row collimation, pitch, and overlap of reconstructed slices were, respectively, 1.25 mm, 3.0, and 50%, showed the highest score for each rating criterion, and highest overall mean score (4.94). Image quality improved as detector-row collimation decreased (Fig. 6); as pitch was reduced from 6.0 to 3.0 (Fig. 7); and as the degree of overlap between reconstructed slices increased (Fig. 8).

Bottom Line: Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering.The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used.Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT

Objective: To determine which multidetector-row helical CT scanning technique provides the best-quality reconstructed 3D images, and to assess differences in image quality according to the levels of the scanning parameters used.

Materials and methods: Four objects with different surfaces and contours were scanned using multidetector-row helical CT at three detector-row collimations (1.25, 2.50, 5.00 mm), two pitches (3.0, 6.0), and three different degrees of overlap between the reconstructed slices (0%, 25%, 50%). Reconstructed 3D images of the resulting 72 sets of data were produced using volumetric rendering. The 72 images were graded on a scale from 1 (worst) to 5 (best) for each of four rating criteria, giving a mean score for each criterion and an overall mean score. Statistical analysis was used to assess differences in image quality according to scanning parameter levels.

Results: The mean score for each rating criterion, and the overall mean score, varied significantly according to the scanning parameter levels used. With regard to detector-row collimation and pitch, all levels of scanning parameters gave rise to significant differences, while in the degree of overlap of reconstructed slices, there were significant differences between overlap of 0% and of 50% in all levels of scanning parameters, and between overlap of 25% and of 50% in overall accuracy and overall mean score. Among the 18 scanning sequences, the highest score (4.94) was achieved with 1.25 mm detector-row collimation, 3.0 pitch, and 50% overlap between reconstructed slices.

Conclusion: Comparison of the quality of reconstructed 3D images obtained using multidetector-row helical CT and various scanning techniques indicated that the 1.25 mm, 3.0, 50% scanning sequence was best. Quality improved as detector-row collimation decreased; as pitch was reduced from 6.0 to 3.0; and as overlap between reconstructed slices increased.

Show MeSH