title: Optimization of Regularization Parameters in Compressed Sensing of Magnetic Resonance Angiography: Can Statistical Image Metrics Mimic Radiologists' Perception?
abstract: In Compressed Sensing (CS) of MRI, optimization of the regularization parameters is not a trivial task. We aimed to establish a method that could determine the optimal weights for regularization parameters in CS of time-of-flight MR angiography (TOF-MRA) by comparing various image metrics with radiologists' visual evaluation. TOF-MRA of a healthy volunteer was scanned using a 3T-MR system. Images were reconstructed by CS from retrospectively under-sampled data by varying the weights for the L1 norm of wavelet coefficients and that of total variation. The reconstructed images were evaluated both quantitatively by statistical image metrics including structural similarity (SSIM), scale invariant feature transform (SIFT) and contrast-to-noise ratio (CNR), and qualitatively by radiologists' scoring. The results of quantitative metrics and qualitative scorings were compared. SSIM and SIFT in conjunction with brain masks and CNR of artery-to-parenchyma correlated very well with radiologists' visual evaluation. By carefully selecting a region to measure, we have shown that statistical image metrics can reflect radiologists' visual evaluation, thus enabling an appropriate optimization of regularization parameters for CS.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Thai
authors.initials: T
authors.lastname: Akasaka
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Okada
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Fushimi
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology; D000066491:Clinical Decision-Making; D044962:Data Compression; D020445:Hospitalists; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D010363:Pattern Recognition, Automated; D010364:Pattern Recognition, Visual; D058996:Quality Improvement; D011856:Radiographic Image Enhancement; D011871:Radiology; D059629:Signal-To-Noise Ratio