Guang-Hong Chen University of Wisconsin–Madison Department of Medical Physics Madison, Wisconsin 53704 and University of Wisconsin–Madison Department of Radiology Madison, Wisconsin 53792 E-mail: [email protected] Abstract. We present a cone-beam image reconstruction algorithm for helical CT scanning with a tilted gantry and N-PI data acquisition. When the gantry is tilted, the effective source t...

BACKGROUND AND PURPOSE Acute intracranial hemorrhage represents a severe and time critical pathology that requires precise and quick diagnosis, mainly by performing a CT scan. The purpose of this study was to compare image quality and intracranial hemorrhage conspicuity in brain CT with sinogram-affirmed iterative reconstruction and filtered back-projection reconstruction techniques at standard...

For all their diagnostic value, computed tomography (CT) examinations have relatively high radiation exposure. Past efforts to decrease patient dose emphasized advances in data acquisition technology because attempts to decrease dose resulted in increased image noise from filtered back projection reconstruction techniques. Iterative reconstruction techniques lead to reduced dose and maintain im...

In computed tomography (CT), there are many situations where reconstruction has to be performed with sparse-view data. In sparse-view CT imaging, strong streak artifacts may appear in conventionally reconstructed images due to limited sampling rate that compromises image quality. Compressed sensing (CS) algorithm has shown potential to accurately recover images from highly undersampled data. In...

Image-guided diffuse optical tomography has the advantage of reducing the total number of optical parameters being reconstructed to the number of distinct tissue types identified by the traditional imaging modality, converting the optical image-reconstruction problem from underdetermined in nature to overdetermined. In such cases, the minimum required measurements might be far less compared to ...

BACKGROUND In integrated PET/MR hybrid imaging the evaluation of PET performance characteristics according to the NEMA standard NU 2-2007 is challenging because of incomplete MR-based attenuation correction (AC) for phantom imaging. In this study, a strategy for CT-based AC of the NEMA image quality (IQ) phantom is assessed. The method is systematically evaluated in NEMA IQ phantom measurements...

The computer algorithm used to reconstruct CT scanner images is very computationally intensive, which forces medical equipment manufacturers to strike a balance among image resolution, image generation time, and system cost when designing a new CT scanner. Cost-effective performance acceleration for image reconstruction would allow manufacturers to generate higher resolution CT images while mai...

Exploiting sparsity in the image gradient magnitude has proved to be an effective means for reducing the sampling rate in the projection view angle in computed tomography (CT). Most of the image reconstruction algorithms, developed for this purpose, solve a nonsmooth convex optimization problem involving the image total variation (TV). The TV seminorm is the ℓ1 norm of the image gradient magnit...

PURPOSE To evaluate dose reduction and image quality of abdominopelvic computed tomography (CT) reconstructed with model-based iterative reconstruction (MBIR) compared to adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHODS In this prospective study, 85 patients underwent referential-, low-, and ultralow-dose unenhanced abdominopelvic CT. Images were reconstructed with ...

This thesis addresses the problem of reconstructing static objects in 2D and 3D transmission computed tomography (CT). After reviewing the classical CT reconstruction theory, we discuss and thoroughly evaluate various novel reconstruction methods, two of which are original. Our first original approach is for 2D CT reconstruction from full-scan fan-beam data, i.e., for 2D imaging in the geometry...