title: Convex optimized diffusion encoding (CODE) gradient waveforms for minimum echo time and bulk motion-compensated diffusion-weighted MRI.
abstract: To evaluate convex optimized diffusion encoding (CODE) gradient waveforms for minimum echo time and bulk motion-compensated diffusion-weighted imaging (DWI).
  
  
  
  Diffusion-encoding gradient waveforms were designed for a range of b-values and spatial resolutions with and without motion compensation using the CODE framework. CODE, first moment (M1) nulled CODE-M1, and first and second moment (M2) nulled CODE-M1M2were used to acquire neuro, liver, and cardiac ADC maps in healthy subjects (n=10) that were compared respectively to monopolar (MONO), BIPOLAR (M1= 0), and motion-compensated (MOCO, M1+ M2= 0) diffusion encoding.
  
  
  
  CODE significantly improved the SNR of neuro ADC maps compared with MONO (19.5 ± 2.5 versus 14.5 ± 1.9). CODE-M1liver ADCs were significantly lower (1.3 ± 0.1 versus 1.8 ± 0.3 × 10-3mm2/s, ie, less motion corrupted) and more spatially uniform (6% versus 55% ROI difference) than MONO and had higher SNR than BIPOLAR (SNR = 14.9 ± 5.3 versus 8.0 ± 3.1). CODE-M1M2cardiac ADCs were significantly lower than MONO (1.9 ± 0.6 versus 3.8 ± 0.3 x10-3mm2/s) throughout the cardiac cycle and had higher SNR than MOCO at systole (9.1 ± 3.9 versus 7.0 ± 2.6) while reporting similar ADCs (1.5 ± 0.2 versus 1.4 ± 0.6 × 10-3mm2/s).
  
  
  
  CODE significantly improved SNR for ADC mapping in the brain, liver and heart, and significantly improved DWI bulk motion robustness in the liver and heart. Magn Reson Med 77:717-729, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Radiological Sciences, University of California, Los Angeles, California, USA.|Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Aliotta
authors.affiliation: Department of Radiological Sciences, University of California, Los Angeles, California, USA.|Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.
authors.forename: Holden H
authors.initials: HH
authors.lastname: Wu
authors.affiliation: Department of Radiological Sciences, University of California, Los Angeles, California, USA.|Biomedical Physics Interdepartmental Program, University of California, Los Angeles, California, USA.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Ennis
mesh_terms: D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio