Effect of Edge-Preserving Adaptive Image Filter on Low-Contrast Detectability in CT Systems: Application of ROC Analysis
Objective. For the multislice CT (MSCT) systems with a larger number of detector rows, it is essential to employ dose-reduction techniques. As reported in previous studies, edge-preserving adaptive image f...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2008-01-01
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| Series: | International Journal of Biomedical Imaging |
| Online Access: | http://dx.doi.org/10.1155/2008/379486 |
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| Summary: | Objective. For the
multislice CT (MSCT) systems with a larger
number of detector rows, it is essential to
employ dose-reduction techniques. As reported in
previous studies, edge-preserving adaptive image
filters, which selectively eliminate only the
noise elements that are increased when the
radiation dose is reduced without affecting the
sharpness of images, have been developed. In the
present study, we employed receiver operating
characteristic (ROC) analysis to assess the
effects of the quantum denoising system (QDS),
which is an edge-preserving adaptive filter that we
have developed, on low-contrast resolution, and
to evaluate to what degree the radiation dose
can be reduced while maintaining acceptable
low-contrast resolution.
Materials and Methods. The low-contrast phantoms (Catphan 412) were scanned at various tube current settings, and ROC analysis was then performed for the groups of images obtained with/without the use of QDS at each tube current to determine whether or not a target could be identified. The tube current settings for which the area under the ROC curve (Az value) was approximately 0.7 were determined for both groups of images with/without the use of QDS. Then, the radiation dose reduction ratio when QDS was used was calculated by converting the determined tube current to the radiation dose.
Results. The use of the QDS edge-preserving adaptive image filter allowed the radiation dose to be reduced by up to 38%.
Conclusion. The QDS was found to be useful for reducing the radiation dose without affecting the low-contrast resolution in MSCT studies. |
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| ISSN: | 1687-4188 1687-4196 |