Reduction of motion artifacts in carotid MRI using free-induction decay navigators

• Published in: Journal of magnetic resonance imaging Vol. 40; no. 1; pp. 214 - 220
• Main Authors: Dyverfeldt, Petter, Deshpande, Vibhas S., Kober, Tobias, Krueger, Gunnar, Saloner, David
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.07.2014; Wiley Subscription Services, Inc
• Subjects: Adult; Algorithms; atherosclerosis; Cardiac-Gated Imaging Techniques - methods; Carotid Arteries - anatomy & histology; carotid artery disease; carotid MRI; Female; FID navigator; Humans; Image Enhancement - methods; Image Interpretation, Computer-Assisted - methods; Magnetic Resonance Angiography - methods; Magnetic resonance imaging; Male; Middle Aged; Motion; motion compensation; motion suppression; Pattern Recognition, Automated - methods; Reproducibility of Results; Sensitivity and Specificity; Young Adult; FID navigator; atherosclerosis; carotid MRI; motion suppression; carotid artery disease; motion compensation
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.24389

Purpose To develop a framework for prospective free‐induction decay (FID)‐based navigator gating for suppression of motion artifacts in carotid magnetic resonance imaging (MRI) and to assess its capability in vivo. Materials and Methods An FID‐navigator, comprising a spatially selective low flip‐angle sinc‐pulse followed by an analog‐to‐digital converter (ADC) readout, was added to a conventional turbo spin‐echo (TSE) sequence. Real‐time navigator processing delivered accept/reject‐and‐reacquire decisions to the sequence. In this Institutional Review Board (IRB)‐approved study, seven volunteers were scanned with a 2D T2‐weighted TSE sequence. A reference scan with volunteers instructed to minimize motion as well as nongated and gated scans with volunteers instructed to perform different motion tasks were performed in each subject. Multiple image quality measures were employed to quantify the effect of gating. Results There was no significant difference in lumen‐to‐wall sharpness (2.3 ± 0.3 vs. 2.3 ± 0.4), contrast‐to‐noise ratio (CNR) (9.0 ± 2.0 vs. 8.5 ± 2.0), or image quality score (3.1 ± 0.9 vs. 2.6 ± 1.2) between the reference and gated images. For images acquired during motion, all image quality measures were higher (P < 0.05) in the gated compared to nongated images (sharpness: 2.3 ± 0.4 vs. 1.8 ± 0.5, CNR: 8.5 ± 2.0 vs. 7.2 ± 2.0, score: 2.6 ± 1.2 vs. 1.8 ± 1.0). Conclusion Artifacts caused by the employed motion tasks deteriorated image quality in the nongated scans. These artifacts were alleviated with the proposed FID‐navigator. J. Magn. Reson. Imaging 2014;40:214–220. © 2013 Wiley Periodicals, Inc.