Adam V Dvorak1,2, Vanessa Wiggermann1,3,4, Guillaume Gilbert5, Irene M Vavasour1,6, Erin L MacMillan4,5,6, Laura Barlow4, Neale Wiley4, Piotr Kozlowski2,4,6, Alex L MacKay1,4,6, Alexander Rauscher1,3,4, Shannon H Kolind1,2,4,6,7. 1. Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada. 2. International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada. 3. Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada. 4. UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada. 5. MR Clinical Science, Philips Canada, Markham, Ontario, Canada. 6. Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada. 7. Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Abstract
PURPOSE: Myelin water imaging (MWI) provides a valuable biomarker for myelin, but clinical application has been restricted by long acquisition times. Accelerating the standard multi-echo T2 acquisition with gradient echoes (GRASE) or by 2D multi-slice data collection results in image blurring, contrast changes, and other issues. Compressed sensing (CS) can vastly accelerate conventional MRI. In this work, we assessed the use of CS for in vivo human MWI, using a 3D multi spin-echo sequence. METHODS: We implemented multi-echo T2 relaxation imaging with compressed sensing (METRICS) and METRICS with partial Fourier acceleration (METRICS-PF). Scan-rescan data were acquired from 12 healthy controls for assessment of repeatability. MWI data were acquired for METRICS in 9 m:58 s and for METRICS-PF in 7 m:25 s, both with 1.5 × 2 × 3 mm3 voxels, 56 echoes, 7 ms ΔTE, and 240 × 240 × 170 mm3 FOV. METRICS was compared with a novel multi-echo spin-echo gold-standard (MSE-GS) MWI acquisition, acquired for a single additional subject in 2 h:2 m:40 s. RESULTS: METRICS/METRICS-PF myelin water fraction had mean: repeatability coefficient 1.5/1.1, coefficient of variation 6.2/4.5%, and intra-class correlation coefficient 0.79/0.84. Repeatability metrics comparing METRICS with METRICS-PF were similar, and both sequences agreed with reference values from literature. METRICS images and quantitative maps showed excellent qualitative agreement with those of MSE-GS. CONCLUSION: METRICS and METRICS-PF provided highly repeatable MWI data without the inherent disadvantages of GRASE or 2D multi-slice acquisition. CS acceleration allows MWI data to be acquired rapidly with larger FOV, higher estimated SNR, more isotropic voxels and more echoes than with previous techniques. The approach introduced here generalizes to any multi-component T2 mapping application.
PURPOSE: Myelin water imaging (MWI) provides a valuable biomarker for myelin, but clinical application has been restricted by long acquisition times. Accelerating the standard multi-echo T2 acquisition with gradient echoes (GRASE) or by 2D multi-slice data collection results in image blurring, contrast changes, and other issues. Compressed sensing (CS) can vastly accelerate conventional MRI. In this work, we assessed the use of CS for in vivo human MWI, using a 3D multi spin-echo sequence. METHODS: We implemented multi-echo T2 relaxation imaging with compressed sensing (METRICS) and METRICS with partial Fourier acceleration (METRICS-PF). Scan-rescan data were acquired from 12 healthy controls for assessment of repeatability. MWI data were acquired for METRICS in 9 m:58 s and for METRICS-PF in 7 m:25 s, both with 1.5 × 2 × 3 mm3 voxels, 56 echoes, 7 ms ΔTE, and 240 × 240 × 170 mm3 FOV. METRICS was compared with a novel multi-echo spin-echo gold-standard (MSE-GS) MWI acquisition, acquired for a single additional subject in 2 h:2 m:40 s. RESULTS: METRICS/METRICS-PF myelin water fraction had mean: repeatability coefficient 1.5/1.1, coefficient of variation 6.2/4.5%, and intra-class correlation coefficient 0.79/0.84. Repeatability metrics comparing METRICS with METRICS-PF were similar, and both sequences agreed with reference values from literature. METRICS images and quantitative maps showed excellent qualitative agreement with those of MSE-GS. CONCLUSION: METRICS and METRICS-PF provided highly repeatable MWI data without the inherent disadvantages of GRASE or 2D multi-slice acquisition. CS acceleration allows MWI data to be acquired rapidly with larger FOV, higher estimated SNR, more isotropic voxels and more echoes than with previous techniques. The approach introduced here generalizes to any multi-component T2 mapping application.
Authors: Cristina Granziera; Jens Wuerfel; Frederik Barkhof; Massimiliano Calabrese; Nicola De Stefano; Christian Enzinger; Nikos Evangelou; Massimo Filippi; Jeroen J G Geurts; Daniel S Reich; Maria A Rocca; Stefan Ropele; Àlex Rovira; Pascal Sati; Ahmed T Toosy; Hugo Vrenken; Claudia A M Gandini Wheeler-Kingshott; Ludwig Kappos Journal: Brain Date: 2021-06-22 Impact factor: 13.501
Authors: Adam V Dvorak; Emil Ljungberg; Irene M Vavasour; Lisa Eunyoung Lee; Shawna Abel; David K B Li; Anthony Traboulsee; Alex L MacKay; Shannon H Kolind Journal: Sci Rep Date: 2021-01-14 Impact factor: 4.379
Authors: Adam V Dvorak; Taylor Swift-LaPointe; Irene M Vavasour; Lisa Eunyoung Lee; Shawna Abel; Bretta Russell-Schulz; Carina Graf; Anika Wurl; Hanwen Liu; Cornelia Laule; David K B Li; Anthony Traboulsee; Roger Tam; Lara A Boyd; Alex L MacKay; Shannon H Kolind Journal: Sci Rep Date: 2021-01-11 Impact factor: 4.379
Authors: Christoph Birkl; Jonathan Doucette; Michael Fan; Enedino Hernández-Torres; Alexander Rauscher Journal: Magn Reson Med Date: 2020-10-05 Impact factor: 4.668