Fig. 2: Illustration of the correction of throughplane distortions. The SEMAC sequence excites multiple slices with no gap in between and resolves the arbitrary distorted excitation slice profiles with the additional z-phase encoding. The correction is done by combining the signals resolved from different slices at each voxel, but many of which only contain background noise. Noise Consideration...

PURPOSE In computed tomography, metallic objects in the scanning field create the so-called metal artifacts in the reconstructed images. Interpolation-based methods for metal artifact reduction (MAR) replace the metal-corrupted projection data with surrogate data obtained from interpolation using the surrounding uncorrupted sinogram information. Prior-based MAR methods further improve interpola...

PURPOSE Metal objects present in x-ray computed tomography (CT) scans are accompanied by physical phenomena that render CT projections inconsistent with the linear assumption made for analytical reconstruction. The inconsistencies create artifacts in reconstructed images. Metal artifact reduction algorithms replace the inconsistent projection data passing through metals with estimates of the tr...

RATIONALE AND OBJECTIVES We propose a novel segmentation-based interpolation method to reduce the metal artifacts caused by surgical aneurysm clips. MATERIALS AND METHODS Our method consists of five steps: coarse image reconstruction, metallic object segmentation, forward-projection, projection interpolation, and final image reconstruction. The major innovations are 2-fold. First, a state-of-...

TAMPERE UNIVERSITY OF TECHNOLOGY International Master’s Degree Programme in Biomedical Engineering US, DEFNE: Metal Artifact Reduction in Sinograms of Dental Computed Tomography Master of Science Thesis, 70 pages, 4 Appendix pages May 2013 Major subject: Biomedical Engineering Examiners: Prof. Ulla Ruotsalainen Prof. Jari Viik M.Sc. Uygar Tuna

Figure 1. Typical out-of-plane artifacts from high-attenuation objects at consecutive heights in the reconstructed volume. Top: needle insertion position is parallel to the X-ray emitter motion lane. Bottom: Needle insertion direction is perpendicular to the X-ray emitter motion lane. Pictures courtesy of Siemens Healthcare Sector. Metal Artifact Reduction of Biopsy Needles in Digital Breast To...

This study proposes a new method for removal of metal artifacts from megavoltage cone beam computed tomography (MVCBCT) and kilovoltage CT (kVCT) images. Both images were combined to obtain prior image, which was forward projected to obtain surrogate data and replace metal trace in the uncorrected kVCT image. The corrected image was then reconstructed through filtered back projection. A similar...

A new method for reducing metal artifacts in X-ray computed tomography (CT) images is presented. It bases on the solution of a convex optimization problem with inequality constraints on the sinogram, and total variation regularization for the reconstructed image. The Chambolle-Pock algorithm is used to numerically solve the discretized version of the optimization problem. As proof of concept we...

Magnetic resonance imaging (MRI) near metallic implants remains an unmet need because of severe artifacts, which mainly stem from large metal-induced field inhomogeneities. This work addresses MRI near metallic implants with an innovative imaging technique called "Slice Encoding for Metal Artifact Correction" (SEMAC). The SEMAC technique corrects metal artifacts via robust encoding of each exci...