In this paper, a shift-invariant filtered backprojection cone-beam image reconstruction algorithm is derived, based upon Katsevich's general inversion scheme, and validated for the source trajectory of two concentric circles. The source trajectory is complete according to Tuy's data sufficiency condition and is used as the basis for an exact image reconstruction algorithm. The algorithm proceed...

Contemporary reconstruction methods employed for clinical helical cone-beam computed tomography (CT) are analytical (noniterative) but mathematically nonexact, i.e., the reconstructed image contains so called cone-beam artifacts, especially for higher cone angles. Besides cone artifacts, these methods also suffer from windmill artifacts: alternating dark and bright regions creating spiral-like ...

3T MRI of the liver has become widely available and is routinely utilized in the clinical setting, but published scientific data comparing 1.5T with 3T is limited. Theoretically, higher field strength is desirable in body imaging owing to an increase in signal-to-noise ratio, greater spectral separation, the potential for faster scan times and improved tissue contrast on dynamic contrast-enhanc...

An expression for the noise power spectrum of images reconstructed by the discrete filtered backprojection algorithm has been derived. The formulation explicitly includes sampling within the projections, angular sampling, and the two-dimensional sampling implicit in the discrete representation of the image. The effects of interpolation are also considered. Noise power spectra predicted by this ...

OBJECTIVE The aim of this study was to evaluate how different iterative and filtered back projection kernels affect the computed tomography (CT) numbers and low contrast detectability. METHODS Five different scans were performed at 6 different tube potentials on the same Catphan 600 phantom using approximately the same dose level and otherwise identical settings. The scans were reconstructed ...

In this paper we analyze the problem of optimal waveform design for syntheticaperture radar (SAR) imaging through a dispersive medium. We use a scalar model for wave propagation, together with the single-scattering approximation, and we assume that measurements are polluted with thermal noise whose statistics are known. For image formation, we use a filtered backprojection algorithm in which th...

BACKGROUND AND PURPOSE Dose-saving techniques in neck CT cause increased image noise that can be counteracted by iterative reconstruction. Our aim was to evaluate the image quality of advanced modeled iterative reconstruction (ADMIRE) in contrast-enhanced low-tube-voltage neck CT. MATERIALS AND METHODS Sixty-one patients underwent 90-kV(peak) neck CT by using third-generation 192-section dual...