PURPOSE Metal artifact reduction (MAR) produces images with improved quality potentially leading to confident and reliable clinical diagnosis and therapy planning. In this work, the authors evaluate the performance of five MAR techniques for the assessment of computed tomography images of patients with hip prostheses. METHODS Five MAR algorithms were evaluated using simulation and clinical st...

Objective: To assess the effect of metal artifact reduction (MAR) algorithm two cone-beam computed tomography (CBCT) software programs on accuracy peri-implant bone width measurements. Material and Methods: This in vitro study evaluated 35 bovine rib blocks measuring 8 x 11 mm. Titanium implants were inserted placed a wax model mandible. CBCT scans obtained with ProMax 3D Cranex systems without...

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-...

Esther Meyer1,2, Rainer Raupach2, Michael Lell3, Bernhard Schmidt2, and Marc Kachelrieß1,4 1Institute of Medical Physics, Friedrich–Alexander University of Erlangen–Nürnberg (FAU), Erlangen, Germany  2Siemens Healthcare, Forchheim, Germany 3Institute of Diagnostic Radiology, Friedrich–Alexander University of Erlangen–Nürnberg (FAU), Erlangen, Germany 4Medical Physics in Radiology, German Cance...

In computed tomography (CT), metal implants increase the inconsistencies between the measured data and the linear assumption made by the analytical CT reconstruction algorithm. The inconsistencies appear in the form of dark and bright bands and streaks in the reconstructed image, collectively called metal artifacts. The standard method for metal artifact reduction (MAR) replaces the inconsisten...

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...

■ Through-plane distortion: The local field offset leads to curved and frayed slices instead of the expected flat image plane (Fig. 1). Since both in-plane and through-plane distortions shift image pixels away from their real positions, image geometry appears to be distorted. In both cases, regions with severe field changes will lead to signal voids visible as black spots and signal pileups vis...

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...