■ 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...

We study samples with full and partial occlusion causing streak artifacts, and propose two modifications of filtered backprojection for artifact removal. Data is obtained by the SPring-8 synchrotron using a monochromatic parallel-beam scan [1]. Thresholding in the sinogram segments the metal, resulting in edges on which we apply 1) a smooth transition, or 2) a Dirichlet boundary condition.

We propose a method, which treats metal artifact reduction in CT by sinogram restoration as a problem of scattered data interpolation. Corrupted sinogram entries are discarded and replaced with artificially generated values. The presented interpolation algorithm is based on the 2D non-equispaced fast Fourier transform (NFFT). Results are compared to two common polynomial interpolation schemes.

PURPOSE To evaluate a method of reducing computed tomography (CT) metal artifacts due to the Fletcher-Suit applicator. METHODS AND MATERIALS We apply a projection-interpolation algorithm to CT images containing artifacts from the brachytherapy applicator. Regions of projection data containing the applicator are interpolated, removing the metal from the projections. A new image is then reconst...

BACKGROUND Artifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images. METHODS Test samples of 44 materials (Metal and Non-Metal) commonl...

BACKGROUND AND PURPOSE Metallic implants induce massive artifacts in CT images which deteriorate image quality and often superimpose structures of interest. The purpose of this study was to apply and evaluate a dedicated MAR method for neuroradiologic intracranial clips and detachable platinum coiling events. We here report the first clinical results for MAR in FDCT. MATERIALS AND METHODS FDC...

X-ray computed tomography (CT) imaging of patients with metallic implants usually suffers from streaking metal artifacts. In this paper, we propose a new projection completion metal artifact reduction (MAR) algorithm by formulating the completion of missing projections as a regularized inverse problem in the wavelet domain. The Douglas-Rachford splitting (DRS) algorithm was used to iteratively ...

Imaging studies are central to the evaluation of persistent or recurrent symptoms after hip arthroplasty. The evaluation starts with radiographs and may be followed by arthrography, aspiration, scintigraphy, sonography, computed tomography, and MR imaging. Common etiologies of a painful or dysfunctional hip arthroplasty are mechanical loosening, polyethylene wear-induced osteolysis, adverse loc...