Removing rician bias in diffusional kurtosis of the prostate using real‐data reconstruction. Issue 6 (18th November 2019)

• Record Type: Journal Article
• Authors: Goodburn, Rosie J.; Barrett, Tristan; Patterson, Ilse; Gallagher, Ferdia A.; Lawrence, Edward M.; Gnanapragasam, Vincent J.; Kastner, Christof; Priest, Andrew N.
• Is Part Of: Magnetic resonance in medicine. Volume 83:Issue 6(2020)
• Page Start: 2243
• Page End: 2252
• Publication Date: 2019-11-18
• Subjects: diffusion weighted MRI -- diffusional kurtosis MRI -- prostate cancer -- quantitative imaging; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.28080
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: To compare prostate diffusional kurtosis imaging (DKI) metrics generated using phase‐corrected real data with those generated using magnitude data with and without noise compensation (NC). Methods: Diffusion‐weighted images were acquired at 3T in 16 prostate cancer patients, measuring 6 b ‐values (0‐1500 s/mm 2 ), each acquired with 6 signal averages along 3 diffusion directions, with noise‐only images acquired to allow NC. In addition to conventional magnitude averaging, phase‐corrected real data were averaged in an attempt to reduce r ician noise‐bias, with a range of phase‐correction low‐pass filter (LPF) sizes (8‐128 pixels) tested. Each method was also tested using simulations. Pixelwise maps of apparent diffusion ( D ) and apparent kurtosis ( K ) were calculated for magnitude data with and without NC and phase‐corrected real data. Average values were compared in tumor, normal transition zone (NTZ), and normal peripheral zone (NPZ). Results: Simulations indicated LPF size can strongly affect K metrics, where 64‐pixel LPFs produced accurate metrics. Relative to metrics estimated from magnitude data without NC, median NC K were lower ( P < 0.0001) by 6/11/8% in tumor/NPZ/NTZ, 64‐LPF real‐data K were lower ( P < 0.0001) by 4/10/7%, respectively. Conclusion: Compared with magnitude data with NC, phase‐corrected real data can produce similar K, although the choice of phase‐correction LPF should be chosen carefully.