Katsuyuki Taguchi PhD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: Longitudinal de-convolution has been developed for better z resolution for helical CT at the expense of increased image noise and enhanced artifact (overshoot error near bone edges or helical artifact). This paper discusses an adaptive approach to improve the z resolution without such side effects. Methods and Materials: We change the strength of z-sharpening as a function of two things: (1) clinical application such as soft tissue imaging, bone imaging, or lung imaging; and (2) the local z-(longitudinal) gradient. For example, if the imaging task is contrast-enhanced blood vessels in a soft tissue background, then we apply the z-sharpening filter when the z-gradient is medium strong (low gradients represents pure soft tissue; high gradients indicate bone edges). On the other hand, if the task is bone imaging, the filter is applied to when z-gradients are high. The algorithm was evaluated with head, lung, and abdomen images obtained with 16-slice helical CT (Aquilion 16, Toshiba, Japan). Results: The z resolution of the targeted anatomical structure (e.g., cerebral blood vessels, bones, or pulmonary vessels, etc.) has been significantly improved without the side effect: Image noise stays the same; the overshoot near bone is minimized; and helical artifact is not enhanced. When the z resolution is measured by a phantom whose contrast is equivalent to the targeted structure, the full width at the half maximum of the section sensitivity profile improves by 17-24 %, depending on clinical applications. Conclusion: The proposed adaptive filtering substantially improves the z resolution of the clinical images without the side effect. (KT and MK are employees of Toshiba Corp., Japan; IAH and MDS from Bio-Imaging Research, Lincolnshire, IL.) (K.T., M.K. are employees of Toshiba Medical Systems, Inc. I.A.H., M.D.S. received grants from Toshiba Medical Systems, Inc.) Questions about this event email: ktaguchi@aol.com

Taguchi PhD, K, An Adaptive Filtering for Improving z-Resolution.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3101878.html