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Luo H, Zhu A, Wiens CN, Starekova J, Shimakawa A, Reeder SB, Johnson KM, Hernando D. Free-breathing liver fat and R 2 ∗ quantification using motion-corrected averaging based on a nonlocal means algorithm. Magn Reson Med 2020; 85:653-666. [PMID: 32738089 DOI: 10.1002/mrm.28439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To propose a motion-robust chemical shift-encoded (CSE) method with high signal-to-noise (SNR) for accurate quantification of liver proton density fat fraction (PDFF) and R 2 ∗ . METHODS A free-breathing multi-repetition 2D CSE acquisition with motion-corrected averaging using nonlocal means (NLM) was proposed. PDFF and R 2 ∗ quantified with 2D CSE-NLM were compared to two alternative 2D techniques: direct averaging and single acquisition (2D 1ave) in a digital phantom. Further, 2D NLM was compared in patients to 3D techniques (standard breath-hold, free-breathing and navigated), and the alternative 2D techniques. A reader study and quantitative analysis (Bland-Altman, correlation analysis, paired Student's t-test) were performed to evaluate the image quality and assess PDFF and R 2 ∗ measurements in regions of interest. RESULTS In simulations, 2D NLM resulted in lower standard deviations (STDs) of PDFF (2.7%) and R 2 ∗ (8.2 s - 1 ) compared to direct averaging (PDFF: 3.1%, R 2 ∗ : 13.6 s - 1 ) and 2D 1ave (PDFF: 8.7%, R 2 ∗ : 33.2 s - 1 ). In patients, 2D NLM resulted in fewer motion artifacts than 3D free-breathing and 3D navigated, less signal loss than 2D direct averaging, and higher SNR than 2D 1ave. Quantitatively, the STDs of PDFF and R 2 ∗ of 2D NLM were comparable to those of 2D direct averaging (p>0.05). 2D NLM reduced bias, particularly in R 2 ∗ (-5.73 to -0.36 s - 1 ) that arises in direct averaging (-3.96 to 11.22 s - 1 ) in the presence of motion. CONCLUSIONS 2D CSE-NLM enables accurate mapping of PDFF and R 2 ∗ in the liver during free-breathing.
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Affiliation(s)
- Huiwen Luo
- Radiology, University of Wisconsin-Madison, Madison, WI, USA.,Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.,Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA
| | - Ante Zhu
- Radiology, University of Wisconsin-Madison, Madison, WI, USA.,Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Curtis N Wiens
- Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jitka Starekova
- Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ann Shimakawa
- Global MR Applications and Workflow, GE Healthcare, Madison, WI, USA
| | - Scott B Reeder
- Radiology, University of Wisconsin-Madison, Madison, WI, USA.,Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,Medicine, University of Wisconsin-Madison, Madison, WI, USA.,Emergency Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin M Johnson
- Radiology, University of Wisconsin-Madison, Madison, WI, USA.,Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Diego Hernando
- Radiology, University of Wisconsin-Madison, Madison, WI, USA.,Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.,Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI, USA
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