The aims of this study were to observe the pattern of transient motion after gadoxetic acid administration including incidence, onset, and duration, and to evaluate the clinical feasibility of free-breathing gadoxetic acid–enhanced liver magnetic resonance imaging using golden-angle radial sparse parallel (GRASP) imaging with respiratory gating.
In this institutional review board–approved prospective study, 59 patients who provided informed consents were analyzed. Free-breathing dynamic T1-weighted images (T1WIs) were obtained using GRASP at 3 T after a standard dose of gadoxetic acid (0.025 mmol/kg) administration at a rate of 1 mL/s, and development of transient motion was monitored, which is defined as a distinctive respiratory frequency alteration of the self-gating MR signals. Early arterial, late arterial, and portal venous phases retrospectively reconstructed with and without respiratory gating and with different temporal resolutions (nongated 13.3-second, gated 13.3-second, gated 6-second T1WI) were evaluated for image quality and motion artifacts. Diagnostic performance in detecting focal liver lesions was compared among the 3 data sets.
Transient motion (mean duration, 21.5 ± 13.0 seconds) was observed in 40.0% (23/59) of patients, 73.9% (17/23) of which developed within 15 seconds after gadoxetic acid administration. On late arterial phase, motion artifacts were significantly reduced on gated 13.3-second and 6-second T1WI (3.64 ± 0.34, 3.61 ± 0.36, respectively), compared with nongated 13.3-second T1WI (3.12 ± 0.51, P < 0.0001). Overall, image quality was the highest on gated 13.3-second T1WI (3.76 ± 0.39) followed by gated 6-second and nongated 13.3-second T1WI (3.39 ± 0.55, 2.57 ± 0.57, P < 0.0001). Only gated 6-second T1WI showed significantly higher detection performance than nongated 13.3-second T1WI (figure of merit, 0.69 [0.63–0.76]) vs 0.60 [0.56–0.65], P = 0.004).
Transient motion developed in 40% (23/59) of patients shortly after gadoxetic acid administration, and gated free-breathing T1WI using GRASP was able to consistently provide acceptable arterial phase imaging in patients who exhibited transient motion.
From the *Department of Radiology, Seoul National University Hospital; †College of Medicine, Seoul National University; ‡Institute of Radiation Medicine, Seoul National University Medical Research Center; §Department of Radiology, Konkuk University School of Medicine, Seoul; ∥Department of Radiology, National Cancer Center Korea, Goyang, Republic of Korea; ¶Siemens Healthcare Gmbh, Erlangen, Germany; #Center for Advanced Imaging Innovation and Research (CAI2R); **Bernard and Irene Schwartz Center for Biomedical Imaging; ††Department of Radiology, New York University School of Medicine, New York, NY; and ‡‡Siemens Healthcare Korea, Seoul, Republic of Korea.
Received for publication May 25, 2017; and accepted for publication, after revision, July 12, 2017.
Correspondence to: Jeong Min Lee, MD, Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea. E-mail: JMSH@SNU.AC.KR; firstname.lastname@example.org.
Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.investigativeradiology.com).