1 / 12

Parallel Imaging

Parallel Imaging. SMASH and SENSE High field advantage Pros and cons … But first, review of last few homework assignments. Bibliography: parallel imaging. Original SMASH and SENSE papers

kinsey
Download Presentation

Parallel Imaging

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Parallel Imaging • SMASH and SENSE • High field advantage • Pros and cons… • But first, review of last few homework assignments Parallel Imaging

  2. Bibliography: parallel imaging • Original SMASH and SENSE papers • Griswold MA, Jakob PM, Chen Q, Goldfarb JW, Manning WJ, Edelman RR, Sodickson DK (1999). Resolution enhancement in single-shot imaging using simultaneous acquisition of spatial harmonics (SMASH). Magn Reson Med. 41(6):1236-45. • Pruessmann KP, Weiger M, Scheidegger MB, Boesiger P (1999). SENSE: sensitivity encoding for fast MRI. Magn Reson Med. 42(5):952-62. • Additional references • Sodickson, DK (2000). Tailored SMASH image reconstructions for robust in vivo parallel MR imaging. Magn Reson Med 44:243-251. • Weiger, M, Boesiger, P, Hilfiker, PR, Weishaupt, D, Pruessmann, KP (2005). Sensitivity encoding as a means of enhancing the SNR efficiency in steady-state MRI. Magn Reson Med 53:177-185. • Griswold MA, Jakob PM, Heidemann RM, Nittka M, Jellus V, Wang J, Kiefer B, Haase A. (2002). Generalized autocalibrating partially parallel acquisitions (GRAPPA). Magn Reson Med. 47(6):1202-1210. • Sodickson, DK, McKenzie, CA (2001). A generalized approach to parallel magnetic resonance imaging. Med Phys 28(8):1629. Parallel Imaging

  3. Parallel Imaging – simplistic overview Coil sensitivity maps Partial k-space data from 2 coils Reconstructed image + = Parallel Imaging

  4. Undersampled k-space = aliased image Full k-space Undersampled k-space Reconstructed image Parallel Imaging

  5. Multiple coils = information to fix aliasing Coils with complementary sensitivities Full k-space Undersampled k-space Parallel Imaging

  6. Parallel Imaging – SENSE ACQUIRE RECONSTRUCT COMBINE Coil sensitivity, partial k-space Images from each coil Images from all coils, using coil sensitivity maps Parallel Imaging

  7. Parallel Imaging – SMASH ACQUIRE RECONSTRUCT COMBINE Coil sensitivity, partial k-space Missing lines of k-space, using coil sensitivity maps Images from all coils Parallel Imaging

  8. SENSE recon: idealized example L1(x,y) Reconstructed  Ln(x,y) = Cn(x,y)*(x,y) + Cn(x,y+NPE/2)*(x,y+NPE/2) Parallel Imaging

  9. Pineapple: fake 2-channel coil, noise (with perfect knowledge of coil sensitivity) Parallel Imaging

  10. Pineapple: fake 2-channel coil, noise (with imperfect knowledge of coil sensitivity) Parallel Imaging

  11. Pineapple: fake 2-channel coil, not ind. Parallel Imaging

  12. Parallel imaging terminology • Methods • iPAT – Siemens name for all of its parallel imaging implementations • SENSE • SMASH • GRAPPA – auto-calibrating SMASH-like technique • Parameters • Reduction factor: integer describing k-space undersampling • g: describes degradation of reconstructed image due to lack of independence between coil sensitivities (limits useful reduction factor) • High field advantage • … of course … Parallel Imaging

More Related