Modern computed tomography systems allow volume imaging of the heart. Up to now, approximately two-dimensional (2D) and 3D algorithms based on filtered backprojection are used for the reconstruction. These algorithms become more sensitive to artifacts when the cone angle of the x-ray beam increases as it is the current trend of computed tomography (CT) technology. In this paper, we investigate the potential of iterative reconstruction based on the algebraic reconstruction technique (ART) for helical cardiac cone-beam CT. Iterative reconstruction has the advantages that it takes the cone angle into account exactly and that it can be combined with retrospective cardiac gating fairly easily. We introduce a modified ART algorithm for cardiac CT reconstruction. We apply it to clinical cardiac data from a 16-slice CT scanner and compare the images to those obtained with a current analytical reconstruction method. In a second part, we investigate the potential of iterative reconstruction for a large area detector with 256 slices. For the clinical cases, iterative reconstruction produces excellent images of diagnostic quality. For the large area detector, iterative reconstruction produces images superior to analytical reconstruction in terms of cone-beam artifacts.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1118/1.1869052 | DOI Listing |
Acta Orthop
January 2025
Emeritus Consultant Orthopaedic Surgeon, Wrightington Hospital; Bristol University, UK.
Background And Purpose: The amount of information publicly available from arthroplasty registries is large but could be used more effectively. This project aims to improve the knowledge concerning existing registries to facilitate access, transparency, harmonization, and reporting.
Methods: Within the International Society of Arthroplasty Registries (ISAR) we aimed at developing, testing, adopting, and making publicly available a short, standardized registry description with items considered relevant for stakeholders using a cross-sectional study survey.
Neuroradiol J
January 2025
Department of Radiology and Radiological Science, Medical University of South Carolina, USA.
We describe a novel application of photon-counting detector CT (PCD-CT) in neurovascular imaging by harnessing the improved spatial resolution, attenuation of electronic noise, and reduction of metal artifacts. The presented case offers the unique challenge of high-quality imaging for the assessment of treated and untreated intracranial saccular aneurysms, in the setting of metal artifacts from embolization coils. Our goal was to explore optimized reconstruction parameters for ultra-high-resolution imaging (UHR) using a dedicated, sharp neurovascular kernel (Hv72) and the highest strength of quantum iterative reconstruction (QIR-4) for detailed characterization of the vasculature.
View Article and Find Full Text PDFJ Comput Assist Tomogr
January 2025
Department of Radiology, the Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University.
Background: With the widespread use of lumbar pedicle screws for internal fixation, the morphology of the screws and the surrounding tissues should be evaluated. The metal artifact reduction (MAR) technique can reduce the artifacts caused by pedicle screws, improve the quality of computed tomography (CT) images after pedicle fixation, and provide more imaging information to the clinic.
Purpose: To explore whether the MAR+ method, a projection-based algorithm for correcting metal artifacts through multiple iterative operations, can reduce metal artifacts and have an impact on the structure of the surrounding metal.
Synchrotron X-ray microtomography (S-µCT) is a highly valuable technique for investigating organ function and pathologies. However, its application is often limited by high radiation doses and the occurrence of ring artifacts. While S-µCT utilizing sparse-view projections can effectively decrease radiation doses, the reconstructed images frequently exhibit severe streaking artifacts, which are exacerbated by ring artifacts, ultimately compromising reconstruction accuracy, image quality, and resolution.
View Article and Find Full Text PDFDue to their advantages of compact geometries and lightweight, diffractive optical elements (DOEs) are attractive in various applications such as sensing, imaging and holographic display. When designing DOEs based on algorithms, a diffraction model is required to trace the diffracted light propagation and to predict the performance. To have more precise diffraction field tracing and optical performance simulation, different diffraction models have been proposed and developed.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!