title: Iterative image reconstruction that includes a total variation regularization for radial MRI.
abstract: This paper presents an iterative image reconstruction method for radial encodings in MRI based on a total variation (TV) regularization. The algebraic reconstruction method combined with total variation regularization (ART_TV) is implemented with a regularization parameter specifying the weight of the TV term in the optimization process. We used numerical simulations of a Shepp-Logan phantom, as well as experimental imaging of a phantom that included a rectangular-wave chart, to evaluate the performance of ART_TV, and to compare it with that of the Fourier transform (FT) method. The trade-off between spatial resolution and signal-to-noise ratio (SNR) was investigated for different values of the regularization parameter by experiments on a phantom and a commercially available MRI system. ART_TV was inferior to the FT with respect to the evaluation of the modulation transfer function (MTF), especially at high frequencies; however, it outperformed the FT with regard to the SNR. In accordance with the results of SNR measurement, visual impression suggested that the image quality of ART_TV was better than that of the FT for reconstruction of a noisy image of a kiwi fruit. In conclusion, ART_TV provides radial MRI with improved image quality for low-SNR data; however, the regularization parameter in ART_TV is a critical factor for obtaining improvement over the FT.
authors.affiliation: Department of Radiology, Tokyo Women's Medical University Medical Center East, 2-1-10 Arakawa-ku, Tokyo, Japan, yancy123xyz@gmail.com.
authors.forename: Shinya
authors.initials: S
authors.lastname: Kojima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinohara
authors.forename: Takeyuki
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Masami
authors.initials: M
authors.lastname: Hirata
authors.forename: Eiko
authors.initials: E
authors.lastname: Ueno
mesh_terms: D029042:Actinidia; D000465:Algorithms; D003198:Computer Simulation; D005638:Fruit; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio