Tomohiro Noda1, Keitaro Sofue2, Ryuji Shimada1, Yuichiro Somiya1, Shintaro Horii1, Yoshiko Ueno2, Naoki Yoshida1, Yu Ueda3, Akiko Kusaka1, and Takamichi Murakami2
1Center of Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan, 2Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 3Philips Japan MR Clinical Science, Tokyo, Japan
1Center of Radiology and Radiation Oncology, Kobe University Hospital, Kobe, Japan, 2Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan, 3Philips Japan MR Clinical Science, Tokyo, Japan
Our phantom study suggests that soft gating factor of 1.4 or higher achieved good image contrast and quality in free-breathing hepatobiliary phase MRI using radial k-space sampling with KWIC reconstruction.
Figure 1: Schematic drawings of respiratory cycle (a) and soft gating method in radial k-space sampling with KWIC reconstruction (b). In the KWIC reconstruction, central k-space data are obtained from only the current temporal phase. Soft gating factor (SGF) means emphasis degree of the obtaining data in the expiratory state. For example, the SGF of 2.0 refers filling central k-space from a half of the data within the expiratory state during respiratory cycle.
Figure 4: Box plots show the results of CR. Each CR was compared with reference standard images. The CR was significantly affected in the imaging set with SGF of 1.025 on the motion distance of 10 mm. In the motion distance of 20 and 30 mm, CRs in the imaging set with SGF of 1.025 and 1.2 were significantly lower than that with the reference standard images.